WorldWideScience

Sample records for blackouts

  1. Blackouts and natural risks

    Science.gov (United States)

    Danihelka, P.; Paldusová, E.; Dobeš, P.

    2009-04-01

    "Blackout" has become the common definition for the situation when electricity supply and demand are not balanced and security of supply fails. These failures have many impacts besides the lights going out, but this term is used commonly. Blackouts have drastic impacts for the society on whole and its citizens and some of them can influence big areas and last for long period, so the consequences are catastrophic. Even if at the European scale, the large extend blackouts are supposed to be exceptional, real frequency is relatively high, approximately once per two years. According to statistics, blackouts are often caused by natural causes, especially lightning. An example of lightning caused blackout is New York blackout 1977, leading to the stand-by of nuclear power plant Indian Point and with overall cost more than 300 mil. USD. There is a clear a distinction between those blackouts caused by nature and those that were caused by other faults. Usually, the nature-caused disturbances as Canada 1988, Sweden 2005 and France 1999, stay inside one country. However, their duration can extend to several weeks, and thus the costs of the interruptions and social impacts are high. Blackouts of only technologic and/or anthropogenic origin are frequently shorter, but may concern more end-users, when cascading from one country to another. Lightning is not the only natural event causing blackouts. Eighteen various case studies of blackout caused by natural events different then lightning were studied and following natural phenomenon found as a root causes: 1x forest fire, 1x snow calamity, 1x ice storm, 1x landslide, 1x high temperature, 1x geomagnetic storm, 2x earthquake, 2x inundation, 2x contact of line with trees, 6x storm (wind, hurricane…). We can conclude, that natural event are frequent cause of blackout of medium or large extend and this phenomena should be studied more in details. This contribution was supported by Ministry of Environment of the Czech Republic.

  2. Alcohol-Induced Blackout

    Directory of Open Access Journals (Sweden)

    Dai Jin Kim

    2009-11-01

    Full Text Available For a long time, alcohol was thought to exert a general depressant effect on the central nervous system (CNS. However, currently the consensus is that specific regions of the brain are selectively vulnerable to the acute effects of alcohol. An alcohol-induced blackout is the classic example; the subject is temporarily unable to form new long-term memories while relatively maintaining other skills such as talking or even driving. A recent study showed that alcohol can cause retrograde memory impairment, that is, blackouts due to retrieval impairments as well as those due to deficits in encoding. Alcoholic blackouts may be complete (en bloc or partial (fragmentary depending on severity of memory impairment. In fragmentary blackouts, cueing often aids recall. Memory impairment during acute intoxication involves dysfunction of episodic memory, a type of memory encoded with spatial and social context. Recent studies have shown that there are multiple memory systems supported by discrete brain regions, and the acute effects of alcohol on learning and memory may result from alteration of the hippocampus and related structures on a cellular level. A rapid increase in blood alcohol concentration (BAC is most consistently associated with the likelihood of a blackout. However, not all subjects experience blackouts, implying that genetic factors play a role in determining CNS vulnerability to the effects of alcohol. This factor may predispose an individual to alcoholism, as altered memory function during intoxication may affect an individual‟s alcohol expectancy; one may perceive positive aspects of intoxication while unintentionally ignoring the negative aspects. Extensive research on memory and learning as well as findings related to the acute effects of alcohol on the brain may elucidate the mechanisms and impact associated with the alcohol- induced blackout.

  3. Modelling, controlling, predicting blackouts

    CERN Document Server

    Wang, Chengwei; Baptista, Murilo S

    2016-01-01

    The electric power system is one of the cornerstones of modern society. One of its most serious malfunctions is the blackout, a catastrophic event that may disrupt a substantial portion of the system, playing havoc to human life and causing great economic losses. Thus, understanding the mechanisms leading to blackouts and creating a reliable and resilient power grid has been a major issue, attracting the attention of scientists, engineers and stakeholders. In this paper, we study the blackout problem in power grids by considering a practical phase-oscillator model. This model allows one to simultaneously consider different types of power sources (e.g., traditional AC power plants and renewable power sources connected by DC/AC inverters) and different types of loads (e.g., consumers connected to distribution networks and consumers directly connected to power plants). We propose two new control strategies based on our model, one for traditional power grids, and another one for smart grids. The control strategie...

  4. Modeling radio communication blackout and blackout mitigation in hypersonic vehicles

    CERN Document Server

    Kundrapu, Madhusudhan; Beckwith, Kristian; Stoltz, Peter; Shashurin, Alexey; Keidar, Michael

    2014-01-01

    A procedure for the modeling and analysis of radio communication blackout of hypersonic vehicles is presented. A weakly ionized plasma generated around the surface of a hypersonic reentry vehicle traveling at Mach 23 was simulated using full Navier-Stokes equations in multi-species single fluid form. A seven species air chemistry model is used to compute the individual species densities in air including ionization - plasma densities are compared with experiment. The electromagnetic wave's interaction with the plasma layer is modeled using multi-fluid equations for fluid transport and full Maxwell's equations for the electromagnetic fields. The multi-fluid solver is verified for a whistler wave propagating through a slab. First principles radio communication blackout over a hypersonic vehicle is demonstrated along with a simple blackout mitigation scheme using a magnetic window.

  5. 77 FR 16175 - Station Blackout

    Science.gov (United States)

    2012-03-20

    ... turbine trip and unavailability of the onsite emergency ac power system). Station blackout does not... plant achieves safe shutdown by relying on components that are not ac powered, such as turbine- or..., or seismic activity and that preexisting licensing requirements specified sufficient...

  6. Computer chaos and the blackout

    CERN Multimedia

    Malik, Rex

    1971-01-01

    A recent electricity dispute resulted in power black-outs with unfortunate consequences for organizations relying on computers. Article discusses the implications of similar events in Britain in the future when computers are even more widely in use (1 1/2 pages).

  7. Blackouts, risk, and fat-tailed distributions

    CERN Document Server

    Weron, R; Simonsen, Ingve; Weron, Rafal

    2005-01-01

    We analyze a 19-year time series of North American electric power transmission system blackouts. Contrary to previously reported results we find a fatter than exponential decay in the distribution of inter-occurrence times and evidence of seasonal dependence in the number of events. Our findings question the use of self-organized criticality, and in particular the sandpile model, as a paradigm of blackout dynamics in power transmission systems. Hopefully, though, they will provide guidelines to more accurate models for evaluation of blackout risk.

  8. Navigation strategy with the spacecraft communications blackout for Mars entry

    Science.gov (United States)

    Wang, Xichen; Xia, Yuanqing

    2015-02-01

    Future Mars missions require precision entry navigation capability, especially in the presence of communications blackout. On the mission of Mars Science Laboratory (MSL), there was a 70-s communications blackout period during atmospheric entry phase. In allusion to the spacecraft communications blackout encountered, this paper predicts an upper-bound for any possible blackout period firstly, improves the default integrated navigation measurements based on IMU and surface radiometric beacons, and proposes innovative attitude observation model based on IMU and range observation model based on orbiters finally. To verify the accuracy and effectiveness of the proposed observation models in the presence of communications blackout, unscented Kalman filter is utilized to demonstrate the navigation performance. The results show that navigation errors based on improved observation models proposed in this paper degrade an order of magnitude compared with the default observation models even if the communications blackout takes place, which satisfies the requirements of future Mars landing missions.

  9. Reactor coolant pump shaft seal stability during station blackout

    Energy Technology Data Exchange (ETDEWEB)

    Rhodes, D B; Hill, R C; Wensel, R G

    1987-05-01

    Results are presented from an investigation into the behavior of Reactor Coolant Pump shaft seals during a potential station blackout (loss of all ac power) at a nuclear power plant. The investigation assumes loss of cooling to the seals and focuses on the effect of high temperature on polymer seals located in the shaft seal assemblies, and the identification of parameters having the most influence on overall hydraulic seal performance. Predicted seal failure thresholds are presented for a range of station blackout conditions and shaft seal geometries.

  10. Reactor coolant pump shaft seal behavior during blackout conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mings, W.J.

    1985-01-01

    The United States Nuclear Regulatory Commission has classified the problem of reactor coolant pump seal failures as an unresolved safety issue. This decision was made in large part due to experimental results obtained from a research program developed to study shaft seal performance during station blackout and reported in this paper. Testing and analysis indicated a potential for pump seal failure under postulated blackout conditions leading to a loss of primary coolant with a concomitant danger of core uncovery. The work to date has not answered all the concerns regarding shaft seal failure but it has helped scope the problem and focus future research needed to completely resolve this issue.

  11. Natural hazard impact on the technosphere: "blackouts

    Science.gov (United States)

    Petrova, E. G.

    2012-04-01

    In recent years, natural-technological accidents (NTA) and disasters are increasing in their number and severity all over the world. The term "natural-technological accident (disaster)" applies for an accident (disaster) in the technosphere triggered by any natural process or phenomenon. Their growth is caused, on the one hand, by observed increasing in the frequency and intensity of some natural hazards and hazardous events due to climate change and, on the other hand, by a growing complication of the modern technosphere exposed to natural impacts and advancement of economic activities into the area at natural risk. The most large-scaled natural-technological disaster happened on March 11, 2011 in Japan, as a result of a massive earthquake and tsunami that caused a number of serious technological accidents, including accidents at "Fukushima-1" nuclear power plant, etc. Severe social, ecological and economic consequences of large-scaled NTA make investigation of these events especially important. The most frequent among NTA occurring in Russia are breakdowns in electric power supply systems that lead to so-called "blackouts" (accidental power outages). They are mainly caused by strong winds, snowstorms, deposition of ice, sleet, and snow, rainfalls, floods, and hailstones. Among other triggers earthquakes, hard frost, fierce heat, thunderstorms, landslides, snow avalanches, and debris flows should be mentioned. The great part of transmission facilities in Russia falls on overhead lines that are especially vulnerable to natural impacts. In general, natural triggers are responsible for more than 70 percent of all accidents in power supply systems. They occur more often in Far East, in the Southern and North-Western federal districts, and in some regions of the Central Russia, which are prone to hurricanes, cyclones, snowstorms, and heavy rainfalls accompanying by hailstones, icing, and sleet. A distinctive feature of these events is their synergistic nature, as power

  12. Reactor coolant pump shaft seal behavior during station blackout

    Energy Technology Data Exchange (ETDEWEB)

    Kittmer, C.A.; Wensel, R.G.; Rhodes, D.B.; Metcalfe, R.; Cotnam, B.M.; Gentili, H.; Mings, W.J.

    1985-04-01

    A testing program designed to provide fundamental information pertaining to the behavior of reactor coolant pump (RCP) shaft seals during a postulated nuclear power plant station blackout has been completed. One seal assembly, utilizing both hydrodynamic and hydrostatic types of seals, was modeled and tested. Extrusion tests were conducted to determine if seal materials could withstand predicted temperatures and pressures. A taper-face seal model was tested for seal stability under conditions when leaking water flashes to steam across the seal face. Test information was then used as the basis for a station blackout analysis. Test results indicate a potential problem with an elastomer material used for O-rings by a pump vendor; that vendor is considering a change in material specification. Test results also indicate a need for further research on the generic issue of RCP seal integrity and its possible consideration for designation as an unresolved safety issue.

  13. 29 CFR 2520.101-3 - Notice of blackout periods under individual account plans.

    Science.gov (United States)

    2010-07-01

    ... beneficiaries pursuant to paragraph (b) of this section. (d) Definitions. For purposes of this section— (1... three consecutive business days. (ii) Exclusions. The term “blackout period” does not include a... otherwise available under the plan, is called a “blackout period.” Whether or not you are...

  14. Station blackout with reactor coolant pump seal leakage

    Energy Technology Data Exchange (ETDEWEB)

    Evinay, A. (Southern California Edison, Irvine, CA (United States))

    1993-01-01

    The U.S. Nuclear Regulatory Commission (NRC) amended its regulations in 10CFR50 with the addition of a new section, 50.63, [open quotes]Loss of All Alternating Current Power.[close quotes] The objective of these requirements is to ensure that all nuclear plants have the capability to withstand a station blackout (SBO) and maintain adequate reactor core cooling and containment integrity for a specified period of time. The NRC also issued Regulatory Guide (RG) 1.155, [open quotes]Station Blackout,[close quotes] to provide guidance for meeting the requirements of 10CFR50.63. Concurrent with RG-1.155, the Nuclear Utility Management and Resources Council (NUMARC) has developed NUMARC 87-00 to address SBO-coping duration and capabilities at light water reactors. Licensees are required to submit a topical report based on NUMARC 87-00 guidelines, to demonstrate compliance with the SBO rule. One of the key compliance criteria is the ability of the plant to maintain adequate reactor coolant system (RCS) inventory to ensure core cooling for the required coping duration, assuming a leak rate of 25 gal/min per reactor coolant pump (RCP) seal in addition to technical specification (TS) leak rate.

  15. Observing power blackouts from space - A disaster related study

    Science.gov (United States)

    Aubrecht, C.; Elvidge, C. D.; Ziskin, D.; Baugh, K. E.; Tuttle, B.; Erwin, E.; Kerle, N.

    2009-04-01

    In case of emergency disaster managers worldwide require immediate information on affected areas and estimations of the number of affected people. Natural disasters such as earthquakes, hurricanes, tornados, wind and ice storms often involve failures in the electrical power generation system and grid. Near real time identification of power blackouts gives a first impression of the area affected by the event (Elvidge et al. 2007), which can subsequently be linked to population estimations. Power blackouts disrupt societal activities and compound the difficulties associated with search and rescue, clean up, and the provision of food and other supplies following a disastrous event. Locations and spatial extents of power blackouts are key considerations in planning and execution of the primary disaster missions of emergency management organizations. To date only one satellite data source has been used successfully for the detection of power blackouts. Operated by NOAA's National Geophysical Data Center (NGDC) the U.S. Air Force Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) offers a unique capability to observe lights present at the Earth's surface at night. Including a pair of visible and thermal spectral bands and originally designed to detect moonlit clouds, this sensor enables mapping of lights from cities and towns, gas flares and offshore platforms, fires, and heavily lit fishing boats. The low light imaging of the OLS is accomplished using a photomultiplier tube (PMT) which intensifies the visible band signal at night. With 14 orbits collected per day and a 3.000 km swath width, each OLS is capable of collecting a complete set of images of the Earth every 24 hours. NGDC runs the long-term archive for OLS data with the digital version extending back to 1992. OLS data is received by NGDC in near real time (1-2 hours from acquisition) and subscription based services for the near real time data are provided for users all over the

  16. Extended station blackout analyses of an APR1400 with MARS-KS

    Directory of Open Access Journals (Sweden)

    Kim Woongbae

    2016-01-01

    Full Text Available The Fukushima Daiichi nuclear power plant accident shows that natural disasters such as earthquakes and the subsequent tsunamis can cause station blackout for several days. The electric energy required for essential systems during a station blackout is provided from emergency backup batteries installed at the nuclear power plant. In South Korea, in the event of an extended station blackout, the life of these emergency backup batteries has recently been extended from 8 hours to 24 hours at Shin-Kori 5, 6, and APR1400 for design certification. For a battery life of 24 hours, available safety means system, equipment and procedures are studied and analyzed in their ability to cope with an extended station blackout. A sensitivity study of reactor coolant pump seal leakage is performed to verify how different seal leakages could affect the system. For simulating extended station blackout scenarios, the best estimate MARS-KS computer code was used. In this paper, an APR1400 RELAP5 input deck was developed for station blackout scenario to analyze operation strategy by manually depressurizing the reactor coolant system through the steam generator's secondary side. Additionally, a sensitivity study on reactor coolant pump seal leakage was carried out.

  17. Impact assessment of the 1977 New York City blackout. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Corwin, J. L.; Miles, W. T.

    1978-07-01

    This study was commissioned by the Division of Electric Energy Systems (EES), Department of Energy (DOE) shortly after the July 13, 1977 New York City Blackout. The objectives were two-fold: to assess the availability and collect, where practical, data pertaining to a wide variety of impacts occurring as a result of the blackout; and to broadly define a framework to assess the value of electric power reliability from consideration of the blackout and its effects on individuals, businesses, and institutions. The impacts were complex and included both economic and social costs. In order to systematically classify the most significant of these impacts and provide guidance for data collection, impact classification schemes were developed. Major economic impact categories examined are business; government; utilities (Consolidated Edison); insurance industry; public health services; and other public services. Impacts were classified as either direct or indirect depending upon whether the impact was due to a cessation of electricity or a response to that cessation. The principal economic costs of the blackout are shown. Social impacts, i.e., the changes in social activities and adaptations to these changes were particularly significant in New York due to its unique demographic and geographic characteristics. The looting and arson that accompanied the blackout set aside the NYC experience from other similar power failures. (MCW)

  18. The August 14,2003 blackout and its importance to China

    Institute of Scientific and Technical Information of China (English)

    P. Jeffrey Palermo

    2004-01-01

    Combining news reports and comments from American circles and according to the Interim Report presented by the August 14 blackout task force,the process and reasons of the blackout were summed up. It was pointed out that due to some new problems caused by American power deregulation such as the weak coordination and control for long distance power transfers, the possibility of blackouts has been increased. The rapid economic development in eastern China sets high requirement for the development of power system.Therefore the current power system in China should be re-evaluated and re-analyzed regularly while the "breakpoints" within the transmission system should be considered in planning and designing to ensure islands operation in time of emergency.

  19. Learning from the blackouts. Transmission system security in competitive electricity markets

    Energy Technology Data Exchange (ETDEWEB)

    none

    2005-07-01

    Electricity market reform has fundamentally changed the environment for maintaining reliable and secure power supplies. Growing inter-regional trade has placed new demands on transmission systems, creating a more integrated and dynamic network environment with new real-time challenges for reliable and secure transmission system operation. Despite these fundamental changes, system operating rules and practices remain largely unchanged. The major blackouts of 2003 and 2004 raised searching questions about the appropriateness of these arrangements. Management of system security needs to be transformed to maintain reliable electricity services in this more dynamic operating environment. These challenges raise fundamental issues for policymakers. This publication presents case studies drawn from recent large-scale blackouts in Europe, North America, and Australia. It concludes that a comprehensive, integrated policy response is required to avoid preventable large-scale blackouts in the future.

  20. 47 CFR 76.120 - Network non-duplication protection, syndicated exclusivity and sports blackout rules for...

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Network non-duplication protection, syndicated... CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout § 76.120 Network non-duplication protection, syndicated exclusivity and sports blackout rules...

  1. Behavior of primary coolant pump shaft seals during station blackout conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hill, R.C.; Rhodes, D.B.

    1986-09-12

    An assessment is made of the ability of typical Reactor Coolant Pump (RCP) Shaft Seals to withstand the conditions predicted for a station blackout (loss of all alternating current power) at a nuclear power station. Several factors are identified that are key to seal stability including inlet fluid conditions, pressure downstream of the seal, and geometrical details of the seal rings. Limits for stable seal operation are determined for various combinations of these factors, and the conclusion is drawn that some RPC seals would be near the threshold of instability during a station blackout. If the threshold were exceeded, significant leakage of coolant from the primary coolant system could be expected.

  2. Parameters important to reactor coolant pump seal stability during station blackout

    Energy Technology Data Exchange (ETDEWEB)

    Hill, R.C.; Rhodes, D.B.

    1986-10-24

    An assessment is made of the ability of typical Reactor Coolant Pump (RCP) Shaft Seals to withstand the conditions predicted for a station blackout (loss of all alternating current power) at a nuclear power station. Several factors are identified that are key to seal stability including inlet fluid conditions, pressure downstream of the seal, and geometrical details of the seal rings. Limits for stable seal operation are determined for various combinations of these factors, and the conclusion is drawn that some RPC seals would be near or over the threshold of instability during a station blackout. If the threshold were exceeded, significant leakage of coolant from the primary coolant system could be expected.

  3. Control and prediction for blackouts caused by frequency collapse in smart grids

    Science.gov (United States)

    Wang, Chengwei; Grebogi, Celso; Baptista, Murilo S.

    2016-09-01

    The electric power system is one of the cornerstones of modern society. One of its most serious malfunctions is the blackout, a catastrophic event that may disrupt a substantial portion of the system, playing havoc to human life and causing great economic losses. Thus, understanding the mechanisms leading to blackouts and creating a reliable and resilient power grid has been a major issue, attracting the attention of scientists, engineers, and stakeholders. In this paper, we study the blackout problem in power grids by considering a practical phase-oscillator model. This model allows one to simultaneously consider different types of power sources (e.g., traditional AC power plants and renewable power sources connected by DC/AC inverters) and different types of loads (e.g., consumers connected to distribution networks and consumers directly connected to power plants). We propose two new control strategies based on our model, one for traditional power grids and another one for smart grids. The control strategies show the efficient function of the fast-response energy storage systems in preventing and predicting blackouts in smart grids. This work provides innovative ideas which help us to build up a robuster and more economic smart power system.

  4. Station Blackout Initiated Event Chronology in LWR/HWR NPP

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Yong; Ahn, Kwang Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    Since the crisis at Fukushima nuclear power plants, a severe accident progression has been recognized as a very important area for an accident management and emergency planning. The purpose of this study is to investigate the comparative characteristics of a severe accident progression among the typical pressurized water reactor (PWR), boiling water reactor (BWR) and pressurized heavy water reactor (PHWR). The OPR 1000-like (ABB-CE type PWR), Peach Bottom-like (BWR/4 RCS with a MARK I Containment), and Wolsong1-like (CANDU6 type) plants are selected as reference plants of typical 1000 MWe PWR, 1140MWe BWR, and 600 MWe PHWR, respectively. The design parameters of these plants are quite different. Some of the major different design features of CANDU6 plant from other light water reactors, in terms of a severe accident, are that the plant adopts a duel primary heat transport system and has an additional amount of cooling water in the calandria vessel (calandria tank, CT) and calandria vault (CV). Another feature is that the CT is always submerged in water because the CV is flooded during normal operation. The containment (reactor building, R/B) failure pressure of the CANDU6 plant is considerably lower than that of the typical PWR or BWR4/MARK-I. The containment vessel free volume of MARK-I is much smaller than that of the PWR or CANDU6 plant. Since there is no steam generator (SG) or passive cooling system, the amount of cooling water inventory in BWR4 is relatively less than other plants. Meanwhile the minimum available time of battery power against station blackout (SBO) accident is different among plant types: six hours for BWR4 and four hours for 1000MWe PWR. Therefore, plant responses against the severe core damage scenarios like Fukushima accident are expected to be much different. By identifying plant response signatures, the appropriate correction actions can be developed as part of severe accident management. A SBO scenario, where all off-site power is lost

  5. On power system blackout modeling and analysis based on self-organized criticality

    Institute of Scientific and Technical Information of China (English)

    MEI ShengWei; XUE AnCheng; ZHANG XueMin

    2008-01-01

    This paper makes a comprehensive survey on power system blackout modeling and analysis based on SOC (self-organized criticality). Firstly, a generalized SOC theory from the viewpoint of cybernetics is introduced. Then the evolution model of power system and its relative mathematical description, which serves as a concrete example of the proposed generalized SOC, are given. Secondly, five blackout models capturing various critical properties of power systems in different time-scales are listed. Finally, this paper analyzes SOC in power systems, such as, the revelation of criticalities of proposed models in both micro-scale and macro-scale which can be used to assess the security of power system, and cascading failures process.

  6. On power system blackout modeling and analysis based on self-organized criticality

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper makes a comprehensive survey on power system blackout modeling and analysis based on SOC (self-organized criticality). Firstly,a generalized SOC theory from the viewpoint of cybernetics is introduced. Then the evolution model of power system and its relative mathematical description,which serves as a concrete example of the proposed generalized SOC,are given. Secondly,five blackout models capturing various critical properties of power systems in different time-scales are listed. Finally,this paper analyzes SOC in power systems,such as,the revelation of criticalities of proposed models in both micro-scale and macro-scale which can be used to assess the security of power system,and cas-cading failures process.

  7. Advanced validation of CFD-FDTD combined method using highly applicable solver for reentry blackout prediction

    OpenAIRE

    Takahashi, Yusuke

    2015-01-01

    An analysis model of plasma flow and electromagnetic waves around a reentry vehicle for radio frequency blackout prediction during aerodynamic heating was developed in this study. The model was validated based on experimental results from the radio attenuation measurement program. The plasma flow properties, such as electron number density, in the shock layer and wake region were obtained using a newly developed unstructured grid solver that incorporated real gas effect models ...

  8. The rotation modulation inertial navigation system for blackout area during hypersonic reentry

    Science.gov (United States)

    Li, Jin; Zhao, Jianhui; Sha, Xiaoqiang; Li, Fan

    2016-10-01

    Navigation of Hypersonic vehicles in the radio frequency (RF) blackout area during atmospheric reentry is challenging as the vehicles can only use the inertial navigation system (INS) as autonomous navigation method in this area. In this paper, strapdown inertial navigation system (SINS) based on the Fiber Optic Gyroscope (FOG) is used for navigation in blackout area. However, without external navigation measurement, the errors of SINS caused by the FOG drift and accelerometer bias would cumulate with time and degrade navigation accuracy. To solve this problem, single axis rotation modulation along with the azimuth axis of the body frame is adopted. The Generic Hypersonic Vehicle (GHV) model designed by NASA Langley Research Center is used to build the reentry fight model which can generate navigation information for simulation. Through derivation the error equations of FOG SINS in the North-East-Down (NED) navigation frame, the principle of error compensation by rotation modulation can be well understood. The simulation results show that rotation modulation can effectively decrease the impact of inertial sensor drift and improve the navigation accuracy in blackout area.

  9. Investigation of plasma–surface interaction effects on pulsed electrostatic manipulation for reentry blackout alleviation

    Science.gov (United States)

    Krishnamoorthy, S.; Close, S.

    2017-03-01

    The reentry blackout phenomenon affects most spacecraft entering a dense planetary atmosphere from space, due to the presence of a plasma layer that surrounds the spacecraft. This plasma layer is created by ionization of ambient air due to shock and frictional heating, and in some cases is further enhanced due to contamination by ablation products. This layer causes a strong attenuation of incoming and outgoing electromagnetic waves including those used for command and control, communication and telemetry over a period referred to as the ‘blackout period’. The blackout period may last up to several minutes and is a major contributor to the landing error ellipse at best, and a serious safety hazard in the worst case, especially in the context of human spaceflight. In this work, we present a possible method for alleviation of reentry blackout using electronegative DC pulses applied from insulated electrodes on the reentry vehicle’s surface. We study the reentry plasma’s interaction with a DC pulse using a particle-in-cell (PIC) model. Detailed models of plasma–insulator interaction are included in our simulations. The absorption and scattering of ions and electrons at the plasma–dielectric interface are taken into account. Secondary emission from the insulating surface is also considered, and its implications on various design issues is studied. Furthermore, we explore the effect of changing the applied voltage and the impact of surface physics on the creation and stabilization of communication windows. The primary aim of this analysis is to examine the possibility of restoring L- and S-band communication from the spacecraft to a ground station. Our results provide insight into the effect of key design variables on the response of the plasma to the applied voltage pulse. Simulations show the creation of pockets where electron density in the plasma layer is reduced three orders of magnitude or more in the vicinity of the electrodes. These pockets extend to

  10. High-Tech, Low-Tech, No-Tech: Communications Strategies During Blackouts

    Science.gov (United States)

    2013-12-01

    hotel guests slept on the street when their electronic key cards stopped working.58 Power was not restored to parts of the affected areas for four days...first-hand when his hotel had no back- up power. His conclusion: “A two-way communications system independent of 89 Mark E. Beatty et al., “Blackout...more than three million chickens . A month after Katrina hit, 19,000 households remained without electric power.100 Alabama did not suffer a direct

  11. Real-time stability in power systems techniques for early detection of the risk of blackout

    CERN Document Server

    Savulescu, Savu

    2014-01-01

    This pioneering volume has been updated and enriched to reflect the state-of-the-art in blackout prediction and prevention. It documents and explains background and algorithmic aspects of the most successful steady-state, transient and voltage stability solutions available today in real-time. It also describes new, cutting-edge stability applications of synchrophasor technology, and captures industry acceptance of metrics and visualization tools that quantify and monitor the distance to instability. Expert contributors review a broad spectrum of additionally available techniques, such as traje

  12. Analysis of hot leg natural circulation under station blackout severe accident

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Under severe accidents, natural circulation flows are important to influence the accident progression and result in a pressurized water reactor (PWR). In a station blackout accident with no recovery of steam generator (SG) auxiliary feedwater (TMLB' severe accident scenario), the hot leg countercurrent natural circulation flow is analyzed by using a severe-accident code, to better understand its potential impacts on the creep-rupture timing among the surge line, the hot leg, and SG tubes. The results show that the natural circulation may delay the failure time of the hot leg.The recirculation ratio and the hot mixing factor are also calculated and discussed.

  13. Investigation of station blackout scenario in VVER440/v230 with RELAP5 computer code

    Energy Technology Data Exchange (ETDEWEB)

    Gencheva, Rositsa Veselinova, E-mail: roseh@mail.bg; Stefanova, Antoaneta Emilova, E-mail: antoanet@inrne.bas.bg; Groudev, Pavlin Petkov, E-mail: pavlinpg@inrne.bas.bg

    2015-12-15

    Highlights: • We have modeled SBO in VVER440. • RELAP5/MOD3 computer code has been used. • Base case calculation has been done. • Fail case calculation has been done. • Operator and alternative operator actions have been investigated. - Abstract: During the development of symptom-based emergency operating procedures (SB-EOPs) for VVER440/v230 units at Kozloduy Nuclear Power Plant (NPP) a number of analyses have been performed using the RELAP5/MOD3 (Carlson et al., 1990). Some of them investigate the response of VVER440/v230 during the station blackout (SBO). The main purpose of the analyses presented in this paper is to identify the behavior of important VVER440 parameters in case of total station blackout. The RELAP5/MOD3 has been used to simulate the SBO in VVER440 NPP model (Fletcher and Schultz, 1995). This model was developed at the Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences (INRNE-BAS), Sofia, for analyses of operational occurrences, abnormal events and design based scenarios. The model provides a significant analytical capability for specialists working in the field of NPP safety.

  14. Silencing Boko Haram: Mobile Phone Blackout and Counterinsurgency in Nigeria’s Northeast region

    Directory of Open Access Journals (Sweden)

    Jacob Udo-Udo Jacob

    2015-03-01

    Full Text Available In the summer of 2013, the Nigerian military, as part of its counterinsurgency operations against Boko Haram insurgents, shut down GSM mobile telephony in three northeast states – Adamawa, Borno and Yobe. This article explores the rationale, impact and citizens’ opinion of the mobile phone blackout. It draws on focus group discussions with local opinion leaders and in-depth personal interviews with military and security insiders, as well as data of Boko Haram incidences before, during and after the blackout from military sources and conflict databases. It argues that, although the mobile phone shutdown was ‘successful’ from a military- tactical point of view, it angered citizens and engendered negative opinions toward the state and new emergency policies. While citizens developed various coping and circumventing strategies, Boko Haram evolved from an open network model of insurgency to a closed centralized system, shifting the center of its operations to the Sambisa Forest. This fundamentally changed the dynamics of the conflict. The shutdown demonstrated, among others, that while ICTs serve various desirable purposes for developing states, they will be jettisoned when their use challenges the state’s legitimacy and raison d'être, but not without consequences.

  15. Analysis of Radio Frequency Blackout for a Blunt-Body Capsule in Atmospheric Reentry Missions

    Directory of Open Access Journals (Sweden)

    Yusuke Takahashi

    2016-01-01

    Full Text Available A numerical analysis of electromagnetic waves around the atmospheric reentry demonstrator (ARD of the European Space Agency (ESA in an atmospheric reentry mission was conducted. During the ARD mission, which involves a 70% scaled-down configuration capsule of the Apollo command module, radio frequency blackout and strong plasma attenuation of radio waves in communications with data relay satellites and air planes were observed. The electromagnetic interference was caused by highly dense plasma derived from a strong shock wave generated in front of the capsule because of orbital speed during reentry. In this study, the physical properties of the plasma flow in the shock layer and wake region of the ESA ARD were obtained using a computational fluid dynamics technique. Then, electromagnetic waves were expressed using a frequency-dependent finite-difference time-domain method using the plasma properties. The analysis model was validated based on experimental flight data. A comparison of the measured and predicted results showed good agreement. The distribution of charged particles around the ESA ARD and the complicated behavior of electromagnetic waves, with attenuation and reflection, are clarified in detail. It is suggested that the analysis model could be an effective tool for investigating radio frequency blackout and plasma attenuation in radio wave communication.

  16. Operative and technological management of super-large united power grids: lessons of major world's blackouts

    Science.gov (United States)

    Brinkis, K.; Kreslins, V.; Mutule, A.

    2014-02-01

    Power system (PS) blackouts still persist worldwide, evidencing that the existing protective structures need to be improved. The discussed requirements and criteria to be met for joint synchronous operation of large and super-large united PSs should be based on close co-ordination of operative and technological management of all PSs involved in order to ensure secure and stable electricity supply and minimise or avoid the threat of a total PS blackout. The authors analyse the July 2012 India blackout - the largest power outage in history, which affected over 620 million people, i.e. half of India's population and spread across its 22 states. The analysis is of a general character, being applicable also to similar blackouts that have occurred in Europe and worldwide since 2003. The authors summarise and develop the main principles and methods of operative and technological management aimed at preventing total blackouts in large and super-large PSs. Neskatoties uz sasniegumiem elektroenerģētikas jomā un energosistēmu nepārtrauktu modernizāciju, pasaulē regulāri notiek sabrukumu avārijas. Rakstā apskatīti lielu un superlielu energosistēmu apvienību savstarpējas sinhronas darbības nodrošinājuma prasības un kritēriji, kas pamatojas uz operatīvās un tehnoloģiskās vadības ciešu koordināciju starp energosistēmām. Savstarpējas sinhronas darbības nodrošinājuma prasībām un kritērijiem ir izšķiroša nozīme, lai panāktu elektroapgādes drošumu un stabilitāti katrā energosistēmā, kas darbojas apvienotas energosistēmas sastāvā. Šo prasību un kritēriju ievērošana sekmē totālo avāriju izcelšanās iespēju samazināšanu un to novēršanu. Indijas 2012.gada totālo avāriju un citu analogo avāriju Eiropā un Amerikā analīze un izvērtējums laika posmā no 2003.gada, deva iespēju apkopot un izstrādāt lielu un superlielu energosistēmu operatīvās un tehnoloģiskās vadības principus un metodoloģiju, lai novērstu vai

  17. An electromagnetic method for removing the communication blackout with a space vehicle upon re-entry into the atmosphere

    Science.gov (United States)

    Cheng, Jianjun; Jin, Ke; Kou, Yong; Hu, Ruifeng; Zheng, Xiaojing

    2017-03-01

    When a hypersonic vehicle travels in the Earth and Mars atmosphere, the surface of the vehicle is surrounded by a plasma layer, which is an envelope of ionized air, created from the compression and heat of the atmosphere by the shock wave. The vehicles will lose contact with ground stations known as the reentry communication blackout. Based on the magnetohydrodynamic framework and electromagnetic wave propagation theory, an analytical model is proposed to describe the effect of the effectiveness of electromagnetic mitigation scheme on removing the reentry communication blackout. C and Global Positioning System (GPS) bands, two commonly used radio bands for communication, are taken as the cases to discuss the effectiveness of the electromagnetic field mitigation scheme. The results show that the electron density near the antenna of vehicles can be reduced by the electromagnetic field, and the required external magnetic field strength is far below the one in the magnetic window method. The directions of the external electric field and magnetic field have a significant impact on the effectiveness of the mitigation scheme. Furthermore, the effect of electron collisions on the required applied electromagnetic field is discussed, and the result indicates that electron collisions are a key factor to analyze the electromagnetic mitigation scheme. Finally, the feasible regions of the applied electromagnetic field for eliminating blackout are given. These investigations could have a significant benefit on the design and optimization of electromagnetic mitigation scheme for the blackout problem.

  18. Proposed SPAR Modeling Method for Quantifying Time Dependent Station Blackout Cut Sets

    Energy Technology Data Exchange (ETDEWEB)

    John A. Schroeder

    2010-06-01

    Abstract: The U.S. Nuclear Regulatory Commission’s (USNRC’s) Standardized Plant Analysis Risk (SPAR) models and industry risk models take similar approaches to analyzing the risk associated with loss of offsite power and station blackout (LOOP/SBO) events at nuclear reactor plants. In both SPAR models and industry models, core damage risk resulting from a LOOP/SBO event is analyzed using a combination of event trees and fault trees that produce cut sets that are, in turn, quantified to obtain a numerical estimate of the resulting core damage risk. A proposed SPAR method for quantifying the time-dependent cut sets is sometimes referred to as a convolution method. The SPAR method reflects assumptions about the timing of emergency diesel failures, the timing of subsequent attempts at emergency diesel repair, and the timing of core damage that may be different than those often used in industry models. This paper describes the proposed SPAR method.

  19. Muerte por sumersión debida a shallow water blackout

    Directory of Open Access Journals (Sweden)

    J.L. Palomo Rando

    2014-09-01

    Full Text Available El llamado shallow water blackout, o síncope de las aguas superficiales, es un accidente que pueden sufrir los buceadores y llevarles a la muerte por sumersión. La natación sumergido (buceando precedida de hiperventilación crea una situación en la que el sujeto puede sufrir hipoxia antes de que la concentración en sangre arterial de dióxido de carbono alcance el nivel que le obligue a salir a la superficie a respirar. En esta situación, el sujeto inconsciente puede respirar bajo el agua y morir por sumersión.

  20. Global blackout following the K/T Chicxulub impact: Results of impact and atmospheric modeling

    Science.gov (United States)

    Pope, K. O.; Ocampo, A. C.; Baines, K. H.; Ivanov, B. A.

    1993-01-01

    Several recent studies have suggested that shock decomposition of anhydrite (CaSO4) target rocks during the K/T Chicxulub impact would have ejected tremendous amounts of sulfur gas into the stratosphere. One of the many potential biospheric effects of this sulfur gas is the generation of a sulfuric acid (H2SO4) aerosol layer capable of causing darkness and severe disruption of photosynthesis for periods of years. In this paper we report the preliminary results of our modeling of shock pressures within the anhydrites and of light attenuation by the H2SO4 aerosol cloud. These models indicate that earlier studies over-estimated the amount of sulfur gas produced, but that more than enough was produced to extend global blackout conditions 4-6 times longer than the approximately 3 month predictions for silicate dust alone.

  1. Demonstration of fully coupled simplified extended station black-out accident simulation with RELAP-7

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haihua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Hongbin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zou, Ling [Idaho National Lab. (INL), Idaho Falls, ID (United States); Anders, David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Martineau, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-10-01

    The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The RELAP-7 code develop-ment effort started in October of 2011 and by the end of the second development year, a number of physical components with simplified two phase flow capability have been de-veloped to support the simplified boiling water reactor (BWR) extended station blackout (SBO) analyses. The demonstration case includes the major components for the primary system of a BWR, as well as the safety system components for the safety relief valve (SRV), the reactor core isolation cooling (RCIC) system, and the wet well. Three scenar-ios for the SBO simulations have been considered. Since RELAP-7 is not a severe acci-dent analysis code, the simulation stops when fuel clad temperature reaches damage point. Scenario I represents an extreme station blackout accident without any external cooling and cooling water injection. The system pressure is controlled by automatically releasing steam through SRVs. Scenario II includes the RCIC system but without SRV. The RCIC system is fully coupled with the reactor primary system and all the major components are dynamically simulated. The third scenario includes both the RCIC system and the SRV to provide a more realistic simulation. This paper will describe the major models and dis-cuss the results for the three scenarios. The RELAP-7 simulations for the three simplified SBO scenarios show the importance of dynamically simulating the SRVs, the RCIC sys-tem, and the wet well system to the reactor safety during extended SBO accidents.

  2. Severe accident analysis of a station blackout accident using MAAP-CANDU for the Point Lepreau station refurbishment project level 2 PSA

    Energy Technology Data Exchange (ETDEWEB)

    Brown, M.J.; Petoukhov, S.M. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2012-07-01

    A Level 2 Probabilistic Safety Assessment was performed for the Point Lepreau Generating Station, using the MAAP-CANDU code to simulate the progression of severe core damage accidents and fission product releases. Five representative severe accidents were selected: Station Blackout, Small Loss-of-Coolant, Stagnation Feeder Break, Steam Generator Tube Rupture, and Shutdown State. Analysis results for the reference station blackout accident are discussed in this paper. (author)

  3. Performance Evaluation of Target Detection with a Near-Space Vehicle-Borne Radar in Blackout Condition.

    Science.gov (United States)

    Li, Yanpeng; Li, Xiang; Wang, Hongqiang; Deng, Bin; Qin, Yuliang

    2016-01-06

    Radar is a very important sensor in surveillance applications. Near-space vehicle-borne radar (NSVBR) is a novel installation of a radar system, which offers many benefits, like being highly suited to the remote sensing of extremely large areas, having a rapidly deployable capability and having low vulnerability to electronic countermeasures. Unfortunately, a target detection challenge arises because of complicated scenarios, such as nuclear blackout, rain attenuation, etc. In these cases, extra care is needed to evaluate the detection performance in blackout situations, since this a classical problem along with the application of an NSVBR. However, the existing evaluation measures are the probability of detection and the receiver operating curve (ROC), which cannot offer detailed information in such a complicated application. This work focuses on such requirements. We first investigate the effect of blackout on an electromagnetic wave. Performance evaluation indexes are then built: three evaluation indexes on the detection capability and two evaluation indexes on the robustness of the detection process. Simulation results show that the proposed measure will offer information on the detailed performance of detection. These measures are therefore very useful in detecting the target of interest in a remote sensing system and are helpful for both the NSVBR designers and users.

  4. Performance Evaluation of Target Detection with a Near-Space Vehicle-Borne Radar in Blackout Condition

    Directory of Open Access Journals (Sweden)

    Yanpeng Li

    2016-01-01

    Full Text Available Radar is a very important sensor in surveillance applications. Near-space vehicle-borne radar (NSVBR is a novel installation of a radar system, which offers many benefits, like being highly suited to the remote sensing of extremely large areas, having a rapidly deployable capability and having low vulnerability to electronic countermeasures. Unfortunately, a target detection challenge arises because of complicated scenarios, such as nuclear blackout, rain attenuation, etc. In these cases, extra care is needed to evaluate the detection performance in blackout situations, since this a classical problem along with the application of an NSVBR. However, the existing evaluation measures are the probability of detection and the receiver operating curve (ROC, which cannot offer detailed information in such a complicated application. This work focuses on such requirements. We first investigate the effect of blackout on an electromagnetic wave. Performance evaluation indexes are then built: three evaluation indexes on the detection capability and two evaluation indexes on the robustness of the detection process. Simulation results show that the proposed measure will offer information on the detailed performance of detection. These measures are therefore very useful in detecting the target of interest in a remote sensing system and are helpful for both the NSVBR designers and users.

  5. SOARCA Peach Bottom Atomic Power Station Long-Term Station Blackout Uncertainty Analysis: Knowledge Advancement.

    Energy Technology Data Exchange (ETDEWEB)

    Gauntt, Randall O.; Mattie, Patrick D.; Bixler, Nathan E.; Ross, Kyle W.; Cardoni, Jeffrey N; Kalinich, Donald A.; Osborn, Douglas.; Sallaberry, Cedric Jean-Marie; Ghosh, S. Tina

    2014-02-01

    This paper describes the knowledge advancements from the uncertainty analysis for the State-of- the-Art Reactor Consequence Analyses (SOARCA) unmitigated long-term station blackout accident scenario at the Peach Bottom Atomic Power Station. This work assessed key MELCOR and MELCOR Accident Consequence Code System, Version 2 (MACCS2) modeling uncertainties in an integrated fashion to quantify the relative importance of each uncertain input on potential accident progression, radiological releases, and off-site consequences. This quantitative uncertainty analysis provides measures of the effects on consequences, of each of the selected uncertain parameters both individually and in interaction with other parameters. The results measure the model response (e.g., variance in the output) to uncertainty in the selected input. Investigation into the important uncertain parameters in turn yields insights into important phenomena for accident progression and off-site consequences. This uncertainty analysis confirmed the known importance of some parameters, such as failure rate of the Safety Relief Valve in accident progression modeling and the dry deposition velocity in off-site consequence modeling. The analysis also revealed some new insights, such as dependent effect of cesium chemical form for different accident progressions. (auth)

  6. SCDAP/RELAP5 analysis of station blackout with pump seal LOCA in Surry plant

    Energy Technology Data Exchange (ETDEWEB)

    Hidaka, Akihide; Soda, Kunihisa; Sugimoto, Jun [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1995-06-01

    During a station blackout of PWR, the pump seal will fail due to loss of the seal cooling. This particular transient-LOCA sequence designated as S3-TMLB` analyzed by SNL with MELPROG/TRAC for Surry plant showed that the depressurization due to the pump seal LOCA would result in early accumulator injection and subsequent core cooling which lead to the delay of reactor pressure vessel (RPV) meltthrough. The present analysis was performed with SCDAP/RELAP5 to evaluate this scenario shown in the MELPROG/TRAC analyses. Additionally, the calculated results were compared with the similar experimental studies of JAERI`s ROSA-IV program. The present analyses showed that: (1) During S3-TMLB`, the loop seal clearing would occur and cause a slight delay of accident progression. (2) It is unlikely that the accumulator injection, which leads to the delay of RPV meltthrough by approximately 60 min, is initiated automatically during S3-TMLB`. Accordingly, an intentional depressurization using PORVs is recommended for the mitigation of the accident consequences. (3) The present SCDAP/RELAP5 analyses did not show significant delay of accident progression. It was found that non-realistic lower heat generation and higher core cooling models used in the MELPROG/TRAC analysis are attributed to this discrepancy. (author).

  7. Analysis of Safety Margins in an Initial Stage during the KALIMER Station Blackout

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Won Pyo; Jeong, Hae Yong; Lee, Yong Bum

    2008-01-15

    The main effort in the present study contributes to investigating the safety margins by analyzing the KALIMER station blackout accident. Natural circulation becomes the main heat transfer mechanism. The flow depends mostly on pump's halving time, friction factor for the wire-wrapped rod bundles in the core, and heat transfer coefficient. Therefore, physical models concerned with heat transfer in both pipe internals (IHX/DHX tube sides) and tube bundles (core, IHX/DHX shell sides), including the core wire-wrapped rod bundles, are also to be assessed in the study. In results, the heat transfer coefficient currently featured in SSC-K for an IHX rod bundle has been found acceptable. The heat transfer coefficient used for the core rod bundle, however, has not shown suitability and thus an alternative one has been proposed. Meanwhile, the friction factor model in SSC-K has not shown a prominent discrepancy in prediction trend but it has not been backed by an enough theoretical basis so that it has been replaced by the Cheng and Todreas model. An assessment matrix has been made to analyze systematically the effects of those parameters affecting on the conservatism of the safety analysis, and the matrix is constituted with the average value and the upper/lower limits in the correlation's applicable ranges. The preliminary calculation has shown negligible effect on the fuel temperature, while the pump halving time and the friction factor for the wire-wrapped rod bundle in the core have affected on the analysis results.

  8. Comparing Simulation Results with Traditional PRA Model on a Boiling Water Reactor Station Blackout Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Zhegang Ma; Diego Mandelli; Curtis Smith

    2011-07-01

    A previous study used RELAP and RAVEN to conduct a boiling water reactor station black-out (SBO) case study in a simulation based environment to show the capabilities of the risk-informed safety margin characterization methodology. This report compares the RELAP/RAVEN simulation results with traditional PRA model results. The RELAP/RAVEN simulation run results were reviewed for their input parameters and output results. The input parameters for each simulation run include various timing information such as diesel generator or offsite power recovery time, Safety Relief Valve stuck open time, High Pressure Core Injection or Reactor Core Isolation Cooling fail to run time, extended core cooling operation time, depressurization delay time, and firewater injection time. The output results include the maximum fuel clad temperature, the outcome, and the simulation end time. A traditional SBO PRA model in this report contains four event trees that are linked together with the transferring feature in SAPHIRE software. Unlike the usual Level 1 PRA quantification process in which only core damage sequences are quantified, this report quantifies all SBO sequences, whether they are core damage sequences or success (i.e., non core damage) sequences, in order to provide a full comparison with the simulation results. Three different approaches were used to solve event tree top events and quantify the SBO sequences: “W” process flag, default process flag without proper adjustment, and default process flag with adjustment to account for the success branch probabilities. Without post-processing, the first two approaches yield incorrect results with a total conditional probability greater than 1.0. The last approach accounts for the success branch probabilities and provides correct conditional sequence probabilities that are to be used for comparison. To better compare the results from the PRA model and the simulation runs, a simplified SBO event tree was developed with only four

  9. Light Water Reactor Sustainability Program: Analysis of Pressurized Water Reactor Station Blackout Caused by External Flooding Using the RISMC Toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Curtis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mandelli, Diego [Idaho National Lab. (INL), Idaho Falls, ID (United States); Prescott, Steven [Idaho National Lab. (INL), Idaho Falls, ID (United States); Alfonsi, Andrea [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rabiti, Cristian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cogliati, Joshua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kinoshita, Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-08-01

    The existing fleet of nuclear power plants is in the process of extending its lifetime and increasing the power generated from these plants via power uprates. In order to evaluate the impact of these factors on the safety of the plant, the Risk Informed Safety Margin Characterization (RISMC) project aims to provide insight to decision makers through a series of simulations of the plant dynamics for different initial conditions (e.g., probabilistic analysis and uncertainty quantification). This report focuses, in particular, on the application of a RISMC detailed demonstration case study for an emergent issue using the RAVEN and RELAP-7 tools. This case study looks at the impact of a couple of challenges to a hypothetical pressurized water reactor, including: (1) a power uprate, (2) a potential loss of off-site power followed by the possible loss of all diesel generators (i.e., a station black-out event), (3) and earthquake induces station-blackout, and (4) a potential earthquake induced tsunami flood. The analysis is performed by using a set of codes: a thermal-hydraulic code (RELAP-7), a flooding simulation tool (NEUTRINO) and a stochastic analysis tool (RAVEN) – these are currently under development at the Idaho National Laboratory.

  10. Light Water Reactor Sustainability Program: Analysis of Pressurized Water Reactor Station Blackout caused by external flooding using the RISMC toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Mandelli, Diego; Smith, Curtis; Prescott, Steven; Alfonsi, Andrea; Rabiti, Cristian; Cogliati, Joshua; Kinoshita, Robert

    2014-08-01

    The existing fleet of nuclear power plants is in the process of extending its lifetime and increasing the power generated from these plants via power uprates. In order to evaluate the impacts of these two factors on the safety of the plant, the Risk Informed Safety Margin Characterization project aims to provide insights to decision makers through a series of simulations of the plant dynamics for different initial conditions (e.g., probabilistic analysis and uncertainty quantification). This paper focuses on the impacts of power uprate on the safety margin of a boiling water reactor for a flooding induced station black-out event. Analysis is performed by using a combination of thermal-hydraulic codes and a stochastic analysis tool currently under development at the Idaho National Laboratory, i.e. RAVEN. We employed both classical statistical tools, i.e. Monte-Carlo, and more advanced machine learning based algorithms to perform uncertainty quantification in order to quantify changes in system performance and limitations as a consequence of power uprate. Results obtained give a detailed investigation of the issues associated with a plant power uprate including the effects of station black-out accident scenarios. We were able to quantify how the timing of specific events was impacted by a higher nominal reactor core power. Such safety insights can provide useful information to the decision makers to perform risk informed margins management.

  11. Branch-and-Bound algorithm applied to uncertainty quantification of a Boiling Water Reactor Station Blackout

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Joseph, E-mail: joseph.nielsen@inl.gov [Idaho National Laboratory, 1955 N. Fremont Avenue, P.O. Box 1625, Idaho Falls, ID 83402 (United States); University of Idaho, Department of Mechanical Engineering and Nuclear Engineering Program, 1776 Science Center Drive, Idaho Falls, ID 83402-1575 (United States); Tokuhiro, Akira [University of Idaho, Department of Mechanical Engineering and Nuclear Engineering Program, 1776 Science Center Drive, Idaho Falls, ID 83402-1575 (United States); Hiromoto, Robert [University of Idaho, Department of Computer Science, 1776 Science Center Drive, Idaho Falls, ID 83402-1575 (United States); Tu, Lei [University of Idaho, Department of Mechanical Engineering and Nuclear Engineering Program, 1776 Science Center Drive, Idaho Falls, ID 83402-1575 (United States)

    2015-12-15

    state. Dynamic PRA (DPRA) methods provide a more rigorous analysis of complex dynamic systems. Unfortunately DPRA methods introduce issues associated with combinatorial explosion of states. This paper presents a methodology to address combinatorial explosion using a Branch-and-Bound algorithm applied to Dynamic Event Trees (DET), which utilize LENDIT (L – Length, E – Energy, N – Number, D – Distribution, I – Information, and T – Time) as well as a set theory to describe system, state, resource, and response (S2R2) sets to create bounding functions for the DET. The optimization of the DET in identifying high probability failure branches is extended to create a Phenomenological Identification and Ranking Table (PIRT) methodology to evaluate modeling parameters important to safety of those failure branches that have a high probability of failure. The PIRT can then be used as a tool to identify and evaluate the need for experimental validation of models that have the potential to reduce risk. In order to demonstrate this methodology, a Boiling Water Reactor (BWR) Station Blackout (SBO) case study is presented.

  12. GSO based optimization of steady state load shedding in power systems to mitigate blackout during generation contingencies

    Directory of Open Access Journals (Sweden)

    R. Mageshvaran

    2015-03-01

    Full Text Available Load shedding is considered as a last alternative to avoid the cascaded tripping and blackout in power systems during generation contingencies. It is essential to optimize the amount of load to be shed in order to prevent excessive load shedding. To minimize load shedding, this paper proposes the implementation of nature inspired optimization algorithm known as glowworm swarm optimization (GSO algorithm. The optimal solution of steady state load shedding is carried out by squaring the difference between the connected and supplied power (active and reactive. The proposed algorithm is tested on IEEE 14, 30, 57, 118 and Northern Regional Power Grid (NRPG-(India 246 bus test systems. The viability of the proposed method in terms of solution quality and convergence properties is compared with the conventional methods, namely, projected augmented Lagrangian method (PALM, gradient technique based on Kuhn–Tucker theorem (GTBKTT and second order gradient technique (SOGT.

  13. Analysis of a Station Black-Out transient in SMR by using the TRACE and RELAP5 code

    Science.gov (United States)

    De Rosa, F.; Lombardo, C.; Mascari, F.; Polidori, M.; Chiovaro, P.; D'Amico, S.; Moscato, I.; Vella, G.

    2014-11-01

    The present paper deals with the investigation of the evolution and consequences of a Station Black-Out (SBO) initiating event transient in the SPES3 facility [1]. This facility is an integral simulator of a small modular reactor being built at the SIET laboratories, in the framework of the R&D program on nuclear fission funded by the Italian Ministry of Economic Development and led by ENEA. The SBO transient will be simulated by using the RELAP5 and TRACE nodalizations of the SPES3 facility. Moreover, the analysis will contribute to study the differences on the code predictions considering the different modelling approach with one and/or three-dimensional components and to compare the capability of these codes to describe the SPES3 facility behaviour.

  14. Emergent transformation games: exploring social innovation agency and activation through the case of the Belgian electricity blackout threat

    Directory of Open Access Journals (Sweden)

    Bonno Pel

    2016-06-01

    Full Text Available The persistence of current societal problems has given rise to a quest for transformative social innovations. As social innovation actors seek to become change makers, it has been suggested that they need to play into impactful macrodevelopments or "game-changers". Here, we aim to deepen the understanding of the social innovation agency in these transformation games. We analyze assumptions about the game metaphor, invoking insights from actor-network theory. The very emergence of transformation games is identified as a crucial but easily overlooked issue. As explored through the recent electricity blackout threat in Belgium, some current transformation games are populated with largely passive players. This illustrative case demonstrates that socially innovative agency cannot be presupposed. In some transformation games, the crucial game-changing effect is to start the game by activating the players.

  15. Can the complex networks help us in the resolution of the problem of power outages (blackouts) in Brazil?

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Paulo Alexandre de; Souza, Thaianne Lopes de [Universidade Federal de Goias (UFG), Catalao, GO (Brazil)

    2011-07-01

    Full text. What the Brazilian soccer championship, Hollywood actors, the network of the Internet, the spread of viruses and electric distribution network have in common? Until less than two decade ago, the answer would be 'nothing' or 'almost nothing'. However, the answer today to this same question is 'all' or 'almost all'. The answer to these questions and more can be found through a sub-area of statistical physics | called science of complex networks that has been used to approach and study the most diverse natural and non-natural systems, such as systems/social networks, information, technological or biological. In this work we study the distribution network of electric power in Brazil (DEEB), from a perspective of complex networks, where we associate stations and/or substations with a network of vertices and the links between the vertices we associate with the transmission lines. We are doing too a comparative study with the best-known models of complex networks, such as Erdoes-Renyi, Configuration Model and Barabasi-Albert, and then we compare with results obtained in real electrical distribution networks. Based on this information, we do a comparative analysis using the following variables: connectivity distribution, diameter, clustering coefficient, which are frequently used in studies of complex networks. We emphasize that the main objective of this study is to analyze the robustness of the network DEEB, and then propose alternatives for network connectivity, which may contribute to the increase of robustness in maintenance projects and/or expansion of the network, in other words our goal is to make the network to proof the blackouts or improve the endurance the network against the blackouts. For this purpose, we use information from the structural properties of networks, computer modeling and simulation. (author)

  16. Development and qualification of a thermal-hydraulic nodalization for modeling station blackout accident in PSB-VVER test facility

    Energy Technology Data Exchange (ETDEWEB)

    Saghafi, Mahdi [Department of Energy Engineering, Sharif University of Technology, Azadi Avenue, Tehran (Iran, Islamic Republic of); Ghofrani, Mohammad Bagher, E-mail: ghofrani@sharif.edu [Department of Energy Engineering, Sharif University of Technology, Azadi Avenue, Tehran (Iran, Islamic Republic of); D’Auria, Francesco [San Piero a Grado Nuclear Research Group (GRNSPG), University of Pisa, Via Livornese 1291, San Piero a Grado, Pisa (Italy)

    2016-07-15

    Highlights: • A thermal-hydraulic nodalization for PSB-VVER test facility has been developed. • Station blackout accident is modeled with the developed nodalization in MELCOR code. • The developed nodalization is qualified at both steady state and transient levels. • MELCOR predictions are qualitatively and quantitatively in acceptable range. • Fast Fourier Transform Base Method is used to quantify accuracy of code predictions. - Abstract: This paper deals with the development of a qualified thermal-hydraulic nodalization for modeling Station Black-Out (SBO) accident in PSB-VVER Integral Test Facility (ITF). This study has been performed in the framework of a research project, aiming to develop an appropriate accident management support tool for Bushehr nuclear power plant. In this regard, a nodalization has been developed for thermal-hydraulic modeling of the PSB-VVER ITF by MELCOR integrated code. The nodalization is qualitatively and quantitatively qualified at both steady-state and transient levels. The accuracy of the MELCOR predictions is quantified in the transient level using the Fast Fourier Transform Base Method (FFTBM). FFTBM provides an integral representation for quantification of the code accuracy in the frequency domain. It was observed that MELCOR predictions are qualitatively and quantitatively in the acceptable range. In addition, the influence of different nodalizations on MELCOR predictions was evaluated and quantified using FFTBM by developing 8 sensitivity cases with different numbers of control volumes and heat structures in the core region and steam generator U-tubes. The most appropriate case, which provided results with minimum deviations from the experimental data, was then considered as the qualified nodalization for analysis of SBO accident in the PSB-VVER ITF. This qualified nodalization can be used for modeling of VVER-1000 nuclear power plants when performing SBO accident analysis by MELCOR code.

  17. Real-Time Smart Grids Control for Preventing Cascading Failures and Blackout using Neural Networks: Experimental Approach for N-1-1 Contingency

    Science.gov (United States)

    Zarrabian, Sina; Belkacemi, Rabie; Babalola, Adeniyi A.

    2016-12-01

    In this paper, a novel intelligent control is proposed based on Artificial Neural Networks (ANN) to mitigate cascading failure (CF) and prevent blackout in smart grid systems after N-1-1 contingency condition in real-time. The fundamental contribution of this research is to deploy the machine learning concept for preventing blackout at early stages of its occurrence and to make smart grids more resilient, reliable, and robust. The proposed method provides the best action selection strategy for adaptive adjustment of generators' output power through frequency control. This method is able to relieve congestion of transmission lines and prevent consecutive transmission line outage after N-1-1 contingency condition. The proposed ANN-based control approach is tested on an experimental 100 kW test system developed by the authors to test intelligent systems. Additionally, the proposed approach is validated on the large-scale IEEE 118-bus power system by simulation studies. Experimental results show that the ANN approach is very promising and provides accurate and robust control by preventing blackout. The technique is compared to a heuristic multi-agent system (MAS) approach based on communication interchanges. The ANN approach showed more accurate and robust response than the MAS algorithm.

  18. 印度大停电与继电保护的三大功能%India blackout and three functions of protective relay

    Institute of Scientific and Technical Information of China (English)

    董新洲; 曹润彬; 王宾; 施慎行; Dominik Bak

    2013-01-01

    On July 30 and 31, 2012, India experienced two electric power blackouts. These two blackouts were both triggered by tripping of zone-3 distance relay of the same transmission line due to overload, and caused unreasonable action of other relays which resulted in cascading trip and led to widespread power blackouts. India's blackouts have exposed the vulnerability of the existing power system, especially the defects of protective relay in case of overload and power swing. Based on the analysis of relay actions in the blackouts, this paper proposes three functions of protective relay to meet the security demand of modern power grid, which are system protection function for security of power system, preventive protection function and the function of rapid removal of fault equipment.%  简介了印度电网在2012年7月30日和7月31日发生的两起大停电事故。两起事故均起源于同一回输电线路距离保护 III 段因过负荷保护动作跳闸,并导致其他设备继电保护的不合理动作而引发连锁跳闸,造成大面积停电。印度大停电事故暴露了现有电力系统的脆弱性,尤其是继电保护在过负荷和系统振荡情况下的动作缺陷。基于对停电事故中继电保护行为的分析,提出了满足现代电网需求的继电保护三大功能:面向系统安全的系统保护功能、预防性保护功能和快速切除故障设备功能。

  19. An Analysis of Station Blackout Sequences Using MELCOR1.8.5 Code for the Severe Accident Analysis DB

    Energy Technology Data Exchange (ETDEWEB)

    Song, Y. M.; Ahn, K. I. [KAERI, Daejeon (Korea, Republic of)

    2010-12-15

    The Korea Atomic Energy Research Institute (KAERI) has been constructing severe accident analysis database (DB) under a National Nuclear R and D Program. Especially, MAAP (commercial code being widely used for industries) DB for many scenarios including station blackout (SBO) has been completed up to now. This report shows the analysis results for SBO scenarios using MELCOR code. These results will be used for the degree of completion after being compared with MAAP results. The developing strategy of MELCOR code is the same with that of MAAP DB. For the generation of data set, the Korean standard nuclear power plant (KSNP) has been selected as a reference plant and the eight SBO scenarios are chosen to be analyzed based on the PSA results (these eight scenarios accounted for 99 percent of occurrence frequency of total 197 SBO scenarios). Both thermal hydraulics (T/H) and source term analysis have been performed using MELCOR version 1.8.5 for the chosen scenarios. But only major T/H variables treated in the MAAP report are listed among the generated data set, which shows the characteristics of each scenario. These SBO results together with those of the other initiating events (to be analyzed in the future) will be used as inputs for DB construction and special value will be found in the comparing and complimentary process with MAAP DB

  20. Long-Term Station Blackout Accident Analyses of a PWR with RELAP5/MOD3.3

    Directory of Open Access Journals (Sweden)

    Andrej Prošek

    2013-01-01

    Full Text Available Stress tests performed in Europe after accident at Fukushima Daiichi also required evaluation of the consequences of loss of safety functions due to station blackout (SBO. Long-term SBO in a pressurized water reactor (PWR leads to severe accident sequences, assuming that existing plant means (systems, equipment, and procedures are used for accident mitigation. Therefore the main objective was to study the accident management strategies for SBO scenarios (with different reactor coolant pumps (RCPs leaks assumed to delay the time before core uncovers and significantly heats up. The most important strategies assumed were primary side depressurization and additional makeup water to reactor coolant system (RCS. For simulations of long term SBO scenarios, including early stages of severe accident sequences, the best estimate RELAP5/MOD3.3 and the verified input model of Krško two-loop PWR were used. The results suggest that for the expected magnitude of RCPs seal leak, the core uncovery during the first seven days could be prevented by using the turbine-driven auxiliary feedwater pump and manually depressurizing the RCS through the secondary side. For larger RCPs seal leaks, in general this is not the case. Nevertheless, the core uncovery can be significantly delayed by increasing RCS depressurization.

  1. Analysis of the FeCrAl Accident Tolerant Fuel Concept Benefits during BWR Station Blackout Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Robb, Kevin R [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    Iron-chromium-aluminum (FeCrAl) alloys are being considered for fuel concepts with enhanced accident tolerance. FeCrAl alloys have very slow oxidation kinetics and good strength at high temperatures. FeCrAl could be used for fuel cladding in light water reactors and/or as channel box material in boiling water reactors (BWRs). To estimate the potential safety gains afforded by the FeCrAl concept, the MELCOR code was used to analyze a range of postulated station blackout severe accident scenarios in a BWR/4 reactor employing FeCrAl. The simulations utilize the most recently known thermophysical properties and oxidation kinetics for FeCrAl. Overall, when compared to the traditional Zircaloy-based cladding and channel box, the FeCrAl concept provides a few extra hours of time for operators to take mitigating actions and/or for evacuations to take place. A coolable core geometry is retained longer, enhancing the ability to stabilize an accident. Finally, due to the slower oxidation kinetics, substantially less hydrogen is generated, and the generation is delayed in time. This decreases the amount of non-condensable gases in containment and the potential for deflagrations to inhibit the accident response.

  2. Developing Fully Coupled Dynamical Reactor Core Isolation System Models in RELAP-7 for Extended Station Black-Out Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Haihua Zhao; Ling Zou; Hongbin Zhang; David Andrs; Richard Martineau

    2014-04-01

    The reactor core isolation cooling (RCIC) system in a boiling water reactor (BWR) provides makeup water to the reactor vessel for core cooling when the main steam lines are isolated and the normal supply of water to the reactor vessel is lost. It was one of the very few safety systems still available during the Fukushima Daiichi accidents after the tsunamis hit the plants and the system successfully delayed the core meltdown for a few days for unit 2 & 3. Therefore, detailed models for RCIC system components are indispensable to understand extended station black-out accidents (SBO) for BWRs. As part of the effort to develop the new generation reactor system safety analysis code RELAP-7, major components to simulate the RCIC system have been developed. This paper describes the models for those components such as turbine, pump, and wet well. Selected individual component test simulations and a simplified SBO simulation up to but before core damage is presented. The successful implementation of the simplified RCIC and wet well models paves the way to further improve the models for safety analysis by including more detailed physical processes in the near future.

  3. Analysis of Long-Term Station Blackout without automatic depressurization at Peach Bottom using MELCOR (Version 1.8)

    Energy Technology Data Exchange (ETDEWEB)

    Madni, I.K. [Brookhaven National Lab., Upton, NY (United States)

    1994-05-01

    This report documents the results from MELCOR calculations of the Long-Term Station Blackout Accident Sequence, with failure to depressurize the reactor vessel, at the Peach Bottom (BWR Mark I) plant, and presents comparisons with Source Term Code Package calculations of the same sequence. STCP has calculated the transient out to 13.5, hours after core uncovery. Most of the MELCOR calculations presented have been carried out to between 15 and 16.7 hours after core uncovery. The results include the release of source terms to the environment. The results of several sensitivity calculations with MELCOR are also presented, which explore the impact of varying user-input modeling and timestep control parameters on the accident progression and release of source terms to the environment. Most of the calculations documented here were performed in FY1990 using MELCOR Version 1.8BC. However, the appendices also document the results of more recent calculations performed in FY1991 using MELCOR versions 1.8CZ and 1.8DNX.

  4. SOARCA Peach Bottom Atomic Power Station Long-Term Station Blackout Uncertainty Analysis: Convergence of the Uncertainty Results

    Energy Technology Data Exchange (ETDEWEB)

    Bixler, Nathan E.; Osborn, Douglas.; Sallaberry, Cedric Jean-Marie; Eckert-Gallup, Aubrey Celia; Mattie, Patrick D.; Ghosh, S. Tina

    2014-02-01

    This paper describes the convergence of MELCOR Accident Consequence Code System, Version 2 (MACCS2) probabilistic results of offsite consequences for the uncertainty analysis of the State-of-the-Art Reactor Consequence Analyses (SOARCA) unmitigated long-term station blackout scenario at the Peach Bottom Atomic Power Station. The consequence metrics evaluated are individual latent-cancer fatality (LCF) risk and individual early fatality risk. Consequence results are presented as conditional risk (i.e., assuming the accident occurs, risk per event) to individuals of the public as a result of the accident. In order to verify convergence for this uncertainty analysis, as recommended by the Nuclear Regulatory Commission’s Advisory Committee on Reactor Safeguards, a ‘high’ source term from the original population of Monte Carlo runs has been selected to be used for: (1) a study of the distribution of consequence results stemming solely from epistemic uncertainty in the MACCS2 parameters (i.e., separating the effect from the source term uncertainty), and (2) a comparison between Simple Random Sampling (SRS) and Latin Hypercube Sampling (LHS) in order to validate the original results obtained with LHS. Three replicates (each using a different random seed) of size 1,000 each using LHS and another set of three replicates of size 1,000 using SRS are analyzed. The results show that the LCF risk results are well converged with either LHS or SRS sampling. The early fatality risk results are less well converged at radial distances beyond 2 miles, and this is expected due to the sparse data (predominance of “zero” results).

  5. The 4 november 2006 blackout: an outage of 'technical' democracy?; Le delestage du 4 novembre 2006: une panne de la democratie technique?

    Energy Technology Data Exchange (ETDEWEB)

    Leteurtrois, J.P

    2007-08-15

    With its power plants and exportation of electricity to neighboring lands, France imagined that it was sheltered from blackouts. But in the autumn of 2006, five million French households were deprived of electricity due to an error by a German operator. What to think of this? The internationalization of the electricity market, though useful to consumers, should not mean deregulation or the relinquishment of rules and regulations to power companies. Supervision of the grid must be reinforced on behalf of all European users of electricity. (author)

  6. OPTIMUM STEADY STATE LOAD SHEDDING USING SHUFFLED FROG LEAPING ALGORITHM TO AVERT BLACKOUT IN POWER SYSTEMS DURING OVERLOAD AND GENERATION CONTINGENCIES

    Directory of Open Access Journals (Sweden)

    R. MAGESHVARAN

    2015-10-01

    Full Text Available During generation and overload contingencies in a power system, the system voltage and frequency will decline due to the deficiency of real and reactive powers. Consequently cascaded failures may occur which will lead to complete blackout of certain parts of the power system. Load shedding is considered as the ultimate step of emergency control action that is necessary to prevent a blackout in the power system. This paper proposes a memetic meta-heuristic algorithm known as shuffled frog leaping algorithm (SFLA to find a solution for the steady state load shedding problem presented here. The optimum steady state load shedding problem uses squares of the difference between the connected active and the reactive load and the supplied active and reactive power. The supplied active and reactive powers are treated as dependent variables modeled as functions of bus voltages only. The proposed algorithm is tested on IEEE 14 and 30 bus test systems. The viability of the proposed method is established by comparison with the other conventional methods presented earlier in terms of solution quality and convergence properties.

  7. Thermal-hydraulic analysis of NSSS and containment response during extended station blackout for Maanshan PWR plant

    Energy Technology Data Exchange (ETDEWEB)

    Yuann, Yng-Ruey, E-mail: ryyuann@iner.gov.tw; Hsu, Keng-Hsien, E-mail: hardlycampus@iner.gov.tw; Lin, Chin-Tsu, E-mail: jtling@iner.gov.tw

    2015-07-15

    Highlights: • Calculate NSSS and containment transient response during extended SBO of 24 h. • RELAP5-3D and GOTHIC models are developed for Maanshan PWR plant. • Reactor coolant pump seal leakage is specifically modeled for each loop. • Analyses are performed with and without secondary-side depressurization, respectively. • Considering different total available time for turbine driven auxiliary feedwater system. - Abstract: A thermal-hydraulic analysis has been performed with respect to the response of the nuclear steam supply system (NSSS) and the containment during an extended station blackout (SBO) duration of 24 h in Maanshan PWR plant. Maanshan plant is a Westinghouse three-loop PWR design with rated core thermal power of 2822 MWt. The analyses in the NSSS and the containment are based on the RELAP5-3D and GOTHIC models, respectively. Important design features of the plant in response to SBO are considered in the respective models, e.g., the steam generator PORVs, turbine driven auxiliary feedwater system (TDAFWS), accumulators, reactor coolant pump (RCP) seal design, various heat structures in the containment, etc. In the analysis it is assumed that the shaft seal in each RCP failed due to loss of seal cooling and the RCS fluid flows to the containment directly. Some parameters calculated from the RELPA5-3D model are input to the containment GOTHIC model, including the RCS average temperature and the RCP seal leakage flow and enthalpy. The RCS average temperature is used to drive the sensible heat transfer to the containment. It is found that the severity of the event depends mainly on whether the secondary side is depressurized or not. If the secondary side is depressurized in time (within 1 h after SBO) and the TDAFWS is available greater than 19 h, then the reactor core will be covered with water throughout the SBO duration, which ensures the integrity of the reactor core. On the contrary, if the secondary side is not depressurized, then the RCS

  8. Lightning rod ionizing natural ionca - Ionic electrode active trimetallictriac of grounding - Definitive and total solution against 'blackouts' and electrical faults generated by atmospheric charges (lightning)

    Energy Technology Data Exchange (ETDEWEB)

    Cabareda, Luis

    2010-09-15

    The Natural Ionizing System of Electrical Protection conformed by: Lightning Rod Ionizing Natural Ionca and Ionic Electrode Active Trimetallic Triac of Grounding offers Total Protection, Maximum Security and Zero Risk to Clinics, Hospitals, Integral Diagnostic Center, avoiding ''the burning'' of Electronics Cards; Refineries, Tanks and Stations of Fuel Provision; Electrical Substations, Towers and Transmission Lines with transformer protection, motors, elevators, A/C, mechanicals stairs, portable and cooling equipment, electrical plants, others. This New High Technology is the solution to the paradigm of Benjamin Franklin and it's the mechanism to end the 'Blackouts' that produces so many damages and losses throughout the world.

  9. Business interruption impacts of a terrorist attack on the electric power system of Los Angeles: customer resilience to a total blackout.

    Science.gov (United States)

    Rose, Adam; Oladosu, Gbadebo; Liao, Shu-Yi

    2007-06-01

    Regional economies are highly dependent on electricity, thus making their power supply systems attractive terrorist targets. We estimate the largest category of economic losses from electricity outages-business interruption-in the context of a total blackout of electricity in Los Angeles. We advance the state of the art in the estimation of the two factors that strongly influence the losses: indirect effects and resilience. The results indicate that indirect effects in the context of general equilibrium analysis are moderate in size. The stronger factor, and one that pushes in the opposite direction, is resilience. Our analysis indicates that electricity customers have the ability to mute the potential shock to their business operations by as much as 86%. Moreover, market resilience lowers the losses, in part through the dampening of general equilibrium effects.

  10. Effect of Coolant Inventories and Parallel Loop Interconnections on the Natural Circulation in Various Heat Transport Systems of a Nuclear Power Plant during Station Blackout

    Directory of Open Access Journals (Sweden)

    Avinash J. Gaikwad

    2008-01-01

    Full Text Available Provision of passive means to reactor core decay heat removal enhances the nuclear power plant (NPP safety and availability. In the earlier Indian pressurised heavy water reactors (IPHWRs, like the 220 MWe and the 540 MWe, crash cooldown from the steam generators (SGs is resorted to mitigate consequences of station blackout (SBO. In the 700 MWe PHWR currently being designed an additional passive decay heat removal (PDHR system is also incorporated to condense the steam generated in the boilers during a SBO. The sustainability of natural circulation in the various heat transport systems (i.e., primary heat transport (PHT, SGs, and PDHRs under station blackout depends on the corresponding system's coolant inventories and the coolant circuit configurations (i.e., parallel paths and interconnections. On the primary side, the interconnection between the two primary loops plays an important role to sustain the natural circulation heat removal. On the secondary side, the steam lines interconnections and the initial inventory in the SGs prior to cooldown, that is, hooking up of the PDHRs are very important. This paper attempts to open up discussions on the concept and the core issues associated with passive systems which can provide continued heat sink during such accident scenarios. The discussions would include the criteria for design, and performance of such concepts already implemented and proposes schemes to be implemented in the proposed 700 MWe IPHWR. The designer feedbacks generated, and critical examination of performance analysis results for the added passive system to the existing generation II & III reactors will help ascertaining that these safety systems/inventories in fact perform in sustaining decay heat removal and augmenting safety.

  11. Analysis of process of ship blackout accident based on surge tube failure%全船断电叠加波动管失效事故分析

    Institute of Scientific and Technical Information of China (English)

    王伟; 陈力生; 张帆; 刘海鹏; 晏峰

    2014-01-01

    利用 MELCOR 程序建立了船用堆计算模型,通过模拟船用堆全船断电事故进程,分析了全船断电事故的热工水力及堆芯失效过程。建立了稳压器波动管蠕变失效模型,实现了 MELCOR 程序对稳压器波动管蠕变失效问题的计算分析。对波动管破口尺寸进行了敏感性分析,结果表明:破口尺寸越大,事故进程越快。全船断电事故舱底的熔穿及稳压器波动管的失效,给船用堆的抗沉性及船内人员健康带来潜在的危害。%A computation model of the marine reactor is established by use of the MELCOR program . The simulation of the process of blackout accident resulting from the marine reactor helps analyze the cause of the thermodynamic and reactor core failure leading to the ship electricity cutoff .Therefore , the creep failure model of pressurizer surge tube is established to make a computation and analysis of the problem of creep failure in the pressurizer surge tube .The sensibility analysis of the breaking size of the surge tube proves that the bigger the breaking ,the faster the accident progresses .It will bring potential hazards to the sinking resistant capability of the marine reactor and to the health of the ship ′s crew because of the melt penetration of the cabin bottom and the failure of pressurizer surge tube in the ship blackout accident .

  12. CPR1000全厂断电事故瞬态特性分析%Transient Analyses of Station Blackout Accident for CPR1000

    Institute of Scientific and Technical Information of China (English)

    张亚培; 田文喜; 秋穗正; 苏光辉

    2011-01-01

    The primary loop of CPR1000 nuclear power plant was modeled using RELAP5/MOD3. 4 code, and the transient thermal hydraulic characteristics were analyzed under the condition of station blackout accident (SBO). The calculation results by RELAP5 code were compared with those of THEMIS code, and the results by RELAP5 code were consistent with those of THEMIS code. The results show that the RELAP5 model can accurately simulate the transient thermal hydraulic characteristics of CPR1000 under the condition of SBO.%用RELAP5/MOD3.4程序对CPR1000压水堆一回路系统进行整体建模,分析全厂断电事故下一回路主要参数的瞬态热工水力特性,并将RELAP5模型计算结果与THEMIS程序的计算结果进行对比,二者符合得较好.计算结果表明:该模型可较准确地模拟CPR1000在事故下的热工水力特性.

  13. An uncertainty analysis of the hydrogen source term for a station blackout accident in Sequoyah using MELCOR 1.8.5

    Energy Technology Data Exchange (ETDEWEB)

    Gauntt, Randall O.; Bixler, Nathan E.; Wagner, Kenneth Charles.

    2014-03-01

    A methodology for using the MELCOR code with the Latin Hypercube Sampling method was developed to estimate uncertainty in various predicted quantities such as hydrogen generation or release of fission products under severe accident conditions. In this case, the emphasis was on estimating the range of hydrogen sources in station blackout conditions in the Sequoyah Ice Condenser plant, taking into account uncertainties in the modeled physics known to affect hydrogen generation. The method uses user-specified likelihood distributions for uncertain model parameters, which may include uncertainties of a stochastic nature, to produce a collection of code calculations, or realizations, characterizing the range of possible outcomes. Forty MELCOR code realizations of Sequoyah were conducted that included 10 uncertain parameters, producing a range of in-vessel hydrogen quantities. The range of total hydrogen produced was approximately 583kg 131kg. Sensitivity analyses revealed expected trends with respected to the parameters of greatest importance, however, considerable scatter in results when plotted against any of the uncertain parameters was observed, with no parameter manifesting dominant effects on hydrogen generation. It is concluded that, with respect to the physics parameters investigated, in order to further reduce predicted hydrogen uncertainty, it would be necessary to reduce all physics parameter uncertainties similarly, bearing in mind that some parameters are inherently uncertain within a range. It is suspected that some residual uncertainty associated with modeling complex, coupled and synergistic phenomena, is an inherent aspect of complex systems and cannot be reduced to point value estimates. The probabilistic analyses such as the one demonstrated in this work are important to properly characterize response of complex systems such as severe accident progression in nuclear power plants.

  14. Blackout Accdent Analyses of AC 600 Nuclear Power Plant%AC600核电厂新电事故分析

    Institute of Scientific and Technical Information of China (English)

    阎义洲; 臧希年

    2002-01-01

    In the advanced pressurized water reactor nuclear power plant design, the passive residual heat removal system is adopted. This system is composed of the secondary side of steam generator, air cooler and air loop which consists of the air cooling tower and atmosphere environment. Wall-air heat exchanging correlation equation is added to the RELAP5 Code. The modified code is used to simulate the AC600 PWR nuclear power plant transient behavior with Passive Residual Heat Removal System (PRHR) in micro-circulation start-up mode after the blackout accident occurs.The calculation results show that the higher the chimney or the larger the air cooler heat transfer area, the more the heat removal capacity of PRHR system. The computational results are consistent with the theoretical analyses.%我国改进型压水堆核电站设计中采用了非能动余热排出系统,它由蒸汽发生器及空气冷却器构成的汽水回路和空气回路组成.本文在RELAP5程序中补充了空气壁面换热结构关系式,分析改进型压水堆核电站(AC600)全厂断电事故后的瞬态行为.结果表明:烟囱高度增加、换热面积增加均使系统的排热能力增强;计算结果与理论分析结果相一致.

  15. Source Term Analysis on Blackout Accident of Marine Reactor%船用堆全船断电事故源项分析

    Institute of Scientific and Technical Information of China (English)

    王伟; 陈力生; 张帆; 蔡琦

    2014-01-01

    Based on the integration program of MELCOR for severe accident analysis , the computational model of a typical marine reactor was established .The creep failure of pressurizer surge tube in the accident of blackout was verified ,and the behavior of the source term before and after the break of surge tube was analyzed .The results show that atmospheric environment and crew would suffer the radioactive harm .The smaller the surge tube break ,the slower the accident process .However ,the external radiation of the crew is slightly increased and the internal radiation is unchanged .The research results can provide a basis on further dose analysis of the source term and the emergency action inside and outside the ship .%本文以一体化严重事故分析程序M ELCOR为研究工具,建立了某型船用堆的计算模型。计算验证了全船断电事故稳压器波动管的蠕变失效,对波动管破损前后的源项行为进行了分析研究。结果表明:波动管失效直接导致对大气环境和船内人员的放射性危害。波动管破损尺寸的减小,导致失效后事故进程减慢,然而对船内人员的外照射危害略有提高,内照射危害相同。本文研究结果可为进一步的源项剂量分析及船内外应急提供依据。

  16. Comparison of MELCOR modeling techniques and effects of vessel water injection on a low-pressure, short-term, station blackout at the Grand Gulf Nuclear Station

    Energy Technology Data Exchange (ETDEWEB)

    Carbajo, J.J.

    1995-06-01

    A fully qualified, best-estimate MELCOR deck has been prepared for the Grand Gulf Nuclear Station and has been run using MELCOR 1.8.3 (1.8 PN) for a low-pressure, short-term, station blackout severe accident. The same severe accident sequence has been run with the same MELCOR version for the same plant using the deck prepared during the NUREG-1150 study. A third run was also completed with the best-estimate deck but without the Lower Plenum Debris Bed (BH) Package to model the lower plenum. The results from the three runs have been compared, and substantial differences have been found. The timing of important events is shorter, and the calculated source terms are in most cases larger for the NUREG-1150 deck results. However, some of the source terms calculated by the NUREG-1150 deck are not conservative when compared to the best-estimate deck results. These results identified some deficiencies in the NUREG-1150 model of the Grand Gulf Nuclear Station. Injection recovery sequences have also been simulated by injecting water into the vessel after core relocation started. This marks the first use of the new BH Package of MELCOR to investigate the effects of water addition to a lower plenum debris bed. The calculated results indicate that vessel failure can be prevented by injecting water at a sufficiently early stage. No pressure spikes in the vessel were predicted during the water injection. The MELCOR code has proven to be a useful tool for severe accident management strategies.

  17. 巴西"2·4"大停电事故及对电网安全稳定运行的启示%Blackout in Brazil Power Grid on February 4, 2011 and Inspirations for Stable Operation of Power Grid

    Institute of Scientific and Technical Information of China (English)

    林伟芳; 汤涌; 孙华东; 郭强; 赵红光; 曾兵

    2011-01-01

    On February 4, 2011, a wide spread electrical blackout occurred in Northeast Brazil power grid. The accident spread 8 states, and about 40 million people were involved. The pre-fault situation, cause, spread and restoration of the blackout are described. The lessons and experiences of the blackout are analyzed and summarized. Some recommendations for ensuring the security and stability of China's power grid and preventing the occurrence of blackout in China are presented.%2011年2月4日,巴西发生了大规模的停电事故.事故覆盖东北部8个州,影响人数约4 000万.文中介绍了事故前巴西电网的运行情况以及事故的起因、发展和恢复过程,分析总结了事故的经验和教训.结合中国电网,提出了保障电网安全稳定运行、防止大停电事故发生的建议.

  18. 从巴西电网"2·4"大停电事故看继电保护技术应用原则%Analyzing Principle of Protection Through the Blackout in Brazil Power Grid on February 4, 2011

    Institute of Scientific and Technical Information of China (English)

    刘宇; 舒治淮; 程逍; 张胜祥

    2011-01-01

    简单介绍了2011年2月4日巴西东北部地区发生的大停电事故.事故由Luiz Gonzaga变电站内保护装置元件故障导致开关失灵保护误动引起.对照本次事故,分析了巴西电网采用的失灵保护逻辑方案的不足,并对中国电网的开关失灵保护标准化方案作了详细的分析.分析结果表明,中国电网开关失灵保护标准化方案能可靠避免该类型事故的发生.%On February 4, 2011, a blackout occurred in Northeast of Brazil. The process of blackout is introduced and analyzed. An error of an electronic component in the relay equipment aroused the false action of the breaker failure protection in the substation Luiz Gonzaga and resulted in the blackout finally. With reference to the blackout incident in Brazil, the deficiency of the breaker failure logic adopted in Brazil power grid is analyzed, and the standard breaker failure logic developed by State Grid Corporation of China is also analyzed. The analysis results reveal that the standard logic can avoid the occurring of similar incidents.

  19. Alternative cooling water flow path for RHR heat exchanger and its effect on containment response during extended station blackout for Chinshan BWR-4 plant

    Energy Technology Data Exchange (ETDEWEB)

    Yuann, Yng-Ruey, E-mail: ryyuann@iner.gov.tw

    2016-04-15

    Highlights: • Motivating alternative RHR heat exchanger tube-side flow path and determining required capacity. • Calculate NSSS and containment response during 24-h SBO for Chinshan BWR-4 plant. • RETRAN and GOTHIC models are developed for NSSS and containment, respectively. • Safety relief valve blowdown flow and energy to drywell are generated by RETRAN. • Analyses are performed with and without reactor depressurization, respectively. - Abstract: The extended Station Blackout (SBO) of 24 h has been analyzed with respect to the containment response, in particular the suppression pool temperature response, for the Chinshan BWR-4 plant of MARK-I containment. The Chinshan plant, owned by Taiwan Power Company, has twin units with rated core thermal power of 1840 MW each. The analysis is aimed at determining the required alternative cooling water flow capacity for the residual heat removal (RHR) heat exchanger when its tube-side sea water cooling flow path is blocked, due to some reason such as earthquake or tsunami, and is switched to the alternative raw water source. Energy will be dissipated to the suppression pool through safety relief valves (SRVs) of the main steam lines during SBO. The RETRAN model is used to calculate the Nuclear Steam Supply System (NSSS) response and generate the SRV blowdown conditions, including SRV pressure, enthalpy, and mass flow rate. These conditions are then used as the time-dependent boundary conditions for the GOTHIC code to calculate the containment pressure and temperature response. The shaft seals of the two recirculation pumps are conservatively assumed to fail due to loss of seal cooling and a total leakage flow rate of 36 gpm to the drywell is included in the GOTHIC model. Based on the given SRV blowdown conditions, the GOTHIC containment calculation is performed several times, through the adjustment of the heat transfer rate of the RHR heat exchanger, until the criterion that the maximum suppression pool temperature

  20. Analysis on the importance of emergency drills of large area blackout in power grid%浅析电网大面积停电应急演练的重要性

    Institute of Scientific and Technical Information of China (English)

    孙建新

    2016-01-01

    The power grid for a long time,a wide range of power can be caused by road traffic congestion, railway outage,commercial organizations and the functions of the government sector paralysis serious consequences,the power supply enterprise management personnel should pay attention to strengthen the large area blackout emergency drills.This paper analyzes the importance of emergency drills,including assessment of emergency status,enhance the awareness of emergency response and enhance the ability of emergency response.%电网长时间、大范围停电可引起公路交通拥堵、铁路停运、商业机构及政府职能部门瘫痪等严重后果,供电企业调控管理人员应重视强化大面积停电应急演练工作。本文分析了应急演练的重要性,包括评估应急状态、增强应急意识及提升应急能力。

  1. A Multi-Objective Optimization Method for Post-Blackout Unit Restoration%电力系统大停电后机组恢复的多目标优化方法

    Institute of Scientific and Technical Information of China (English)

    朱冬雪; 顾雪平; 钟慧荣

    2013-01-01

    大停电后的机组恢复策略多为单目标优化,忽略了大量影响机组启动顺序的因素,为此提出了机组恢复的多目标优化策略.以机组启动后提供的发电量尽可能大、已恢复的电源点尽量在网架层面铺开、有利于后续厂站层机组和重要负荷的恢复为优化目标,建立机组恢复的多目标优化模型.先将恢复过程划分为一系列顺序执行的恢复时步,再将每一时步的优化问题转化成多目标“0/1背包”问题;结合最短路径法为机组恢复方案搜索恢复路径,采用快速非支配排序遗传算法进行求解;最后对每时步的Pareto最优方案排序,确定最优解.算例结果验证了该方法的有效性.%Most post-blackout unit restoration strategies are based on single-objective optimization and factors influencing the starting sequence of units are neglected.A multi-objective optimization strategy for post-blackout unit restoration is proposed and a multi-objective optimization model for unit restoration,in which following items are taken as optimization objectives:the generating capacity of restored units should be as much as possible,the restored units should be distributed in the network frame level as possible and the restored units are favorable to the restoration of important loads and follow-up units to be restored in power plant level,is built.Firstly,the restoration process is divided into a series of restoration steps to be executed sequentially; secondly,the optimization of each restoration step is turned into multi-objective 0/1 knapsack problem and combining with the shortest path method the restoration paths for unit restoration scheme are searched,and then the restoration paths are solved by.fast and elitist non-dominated sorting genetic algorithm and classic Dijkstra algorithm is employed to select restoration paths; finally,the Pareto optimal solutions are sorted to determine the optimal solution.The effectiveness of the proposed

  2. Lessons from September 8, 2011 Southwest America Blackout for Prevention and Control of Cascading Outages%美国“9·8”大停电对连锁故障防控技术的启示

    Institute of Scientific and Technical Information of China (English)

    方勇杰

    2012-01-01

    Based on the 2011 Southwest America blackout inquiry report, this paper presents a description of the event evolution and an analysis of technical causes leading to the cascade development from the point of view of prevention and control of cascading outages, including ineffectiveness of security analysis and preventive control, inadequacy of real-time situational awareness, unreasonabilitp of protection relay settings, inappropriateness of control system design and lack of coordination between protection and control. It concludes that several fundamental measures need to be strengthened, including a complete, thorough and timely understanding of system dynamic characteristics, coordination of protection and control actions, and improvement of simulation analysis.%叙述了2011年9月8日在美国西南地区电网发生的大停电事故演化过程,从连锁故障防控的视角分析了事故发展的技术原因,包括安全分析和预防控制技术欠缺、实时状态觉知能力不足、保护定值整定不合理、控制方案设置不当和保护与控制动作不协调。凝练了连锁故障防控技术需要加强的基础性工作,指出必须全面、深入、及时地掌握系统动态特性,协调保护控制动作,提高仿真分析精度。

  3. Accident Process and Consequence Research for LOCA Combining with Blackout Accident of Ship Reactor%船用堆破口叠加全船断电事故进程及后果研究

    Institute of Scientific and Technical Information of China (English)

    张帆; 陈航; 张彦招; 晏峰

    2015-01-01

    Using MELCOR code ,the combination of LOCA and blackout accident of ship reactor was modeled and calculated , and the accident process and source term release were researched . The results show that the accident leads to lower head of pressure vessel and bilge creep‐rupture finally without emergency power .The release fraction of inert gases and iodine are above 80% ,the main form of iodine is CsI with great deposit and less airborne fraction .The accident process is decided by the equiva‐lent diameter of break size .The production of H2 is decided by core temperature and water remaining in the core ,but has nothing to do with equivalent diameter of break size .T he probability of H2 detonation is unlikely to occur .T he results can provide tech‐nical support for emergency maintenance and emergency decision‐making .%采用M ELCOR程序,对船用堆破口叠加全船断电事故进行建模计算,并对事故进程和源项释放进行了研究。计算结果表明:若应急电源无法投入,最终将导致压力容器下封头失效和舱底失效;所研究事故的惰性气体、碘释放量均在80%以上,且释放的I主要以CsI形式存在,滞留量大,气载量小。事故进展快慢取决于破口当量尺寸,但氢气的产量与堆芯温度、堆芯残余水量相关,与破口当量尺寸无直接关系,堆舱内发生氢爆可能性不大。本文计算结果可为应急抢修和应急决策提供技术支持。

  4. AP1000核电厂应对全厂断电事故的稳压器防满溢对策研究%AP1000 Plant Pressurizer Overfilling Prevention Study Against Station Blackout Accident

    Institute of Scientific and Technical Information of China (English)

    刘展; 王喆; 张国胜; 秦慧敏

    2014-01-01

    If loss of main feed-water occurs in a station blackout accident for AP1000 plant ,the pressurizer will overfill and the coolant will be discharged through pressurizer safety valves .It results in a loss of coolant accident ,RCS inventory will decrease ,and the risk of reactor core uncovering increases .Because of the coolant discharging , the atmosphere radiation level in the containment may be raised , w hile the possibility of radioactive release to the environment increases .In order to prevent pressurizer overfill-ing ,an effective strategy to avoid and mitigate pressurizer overfilling was provided .The results show that increasing heat transfer areas of PRHRS heat exchanger can prevent pressurizer overfilling ;reasonable decreasing of IRWST back pressure can enhance mar-gins of pressurizer overfilling , and mitigate pressurizer overfilling phenomena ;increasing pressurizer volumes can also avoid pressurizer overfilling . T he conclusions have reference value in helping design and safety analysis of AP 1000 plant .%A P1000核电厂若在全厂断电事故下丧失正常给水,会引起稳压器满溢,将通过稳压器安全阀排放液体冷却剂,引起反应堆冷却剂水装量流失,增大反应堆堆芯裸露的风险。与此同时,安全壳内的放射性水平因稳压器满溢可能会增大,增大向环境排放大量放射物质的可能。为防止稳压器满溢,本工作进行了解决或缓解稳压器满溢的对策研究。结果表明,增大非能动余热排出系统(PRHRS )热交换器的传热面积,可防止稳压器满溢;合理降低安全壳内置换料水箱(IRWST )的背压,可增大达到稳压器满溢的裕度,有效地缓解稳压器满溢;增大稳压器的自由容积,可防止稳压器满溢。此结论对A P1000核电厂的设计和事故分析有一定的参考作用。

  5. Summary and revelation of "2009· 11· 10" and "2011 · 2· 4" blackouts in Brazil Power System%巴西“2009-11-10”和“2011-2-4”大停电事故及启示

    Institute of Scientific and Technical Information of China (English)

    邹江峰; 章显亮

    2011-01-01

    Based on the survey report of ONS (National Power System Operator) in Brazil, "2009·11·10" Wand "2011·2·4"blackout are described. The pre-fault condition, fault causes, spread and restoration process are analyzed. According to the summary of lessons and experience learned from these blackouts, recommendations are presented to improve security operation of power system in China.%查阅了巴西电网运行部门对巴西“2009·11·10”和“2011·2·4”大停电事故调查报告,简要描述了这2次停电的事故过程,重点回顾了具有典型特征的“2009·11·10”巴西大停电的事故经过,通过对事故的发生、发展和恢复过程的描述及事故原因的分析,借鉴国外停电事故的经验教训,结合我国电网的实际情况,总结了对我国电网安全运行的启示.

  6. 78 FR 44035 - Station Blackout Mitigation Strategies

    Science.gov (United States)

    2013-07-23

    ... rulemaking (PRM), both submitted by the Natural Resources Defense Council that are being addressed within this rulemaking. Those are PRM-50-100 (notice of consideration published in the Proposed Rules section of this issue of the Federal Register (NRC-2011-0189)) and PRM- 50-101 (77 FR 16483; March 21,...

  7. Foreign Technology,to Alleviate the Blackout

    Institute of Scientific and Technical Information of China (English)

    JEFFFLORY

    2004-01-01

    Torrid domestic economic growth is feeding a mammoth appetite for energy. As a partial remedy, the Chinese government has swung decisively in favor of nuclear power. While this comes as great news to the world's major nuclear energy companies, it remains to be seen who is going to be let in on the action and who will be left out.

  8. 78 FR 21275 - Station Blackout Mitigation Strategies

    Science.gov (United States)

    2013-04-10

    ... provides a discussion of rule language concepts that the NRC staff is considering for this potential... 2011 Fukushima Dai-ichi Nuclear Power Plant accident in Japan. DATES: Submit comments by May 28, 2013... discussion of rule language concepts that the NRC staff is considering for this potential...

  9. 蒸汽发生器传热管破损叠加全船断电事故放射性分析%Radioactive Analysis on Accident of SG-tube Rupture Coupled with Whole Ship Blackout

    Institute of Scientific and Technical Information of China (English)

    王伟; 陈力生; 张帆; 刘海鹏

    2015-01-01

    Based on MELCOR which is the severe accident analysis integration program , the accident of SG‐tube rupture coupled with whole ship blackout was researched . Considering the release of radioactive material to other cabins in the case of SG‐tube rupture ,the release ,migration ,retention and distribution characteristics of the noble gas and CsI were analyzed . The result shows that steam pipe of the secondary loop would be overpressure failure and hydrogen combustion would result in overpressure failure of the adjacent ones of reactor cabin . At the end of the computation , about 99.61% of Xe and 49.96% of CsI in total cumulative amount were released from the reactor core .In cabin Ⅰ and Ⅱ ,the distribution fraction of Xe was 38% and 18% ,and it was 22.2% and 2.7% for CsI respectively .CsI was mainly resided in the bottom pool of the reactor cabin ,and a small amount of the CsI was leaked to the cabinⅡ .The anal‐ysis results will provide help for further analysis on the source dose and for emergency inside and outside the ship .%以严重事故分析程序M ELCOR为计算工具,研究了某型船用堆发生蒸汽发生器传热管破损叠加全船断电事故,针对传热管破损所导致的放射性物质向其他舱室的泄漏,着重分析了惰性气体和CsI的释放、迁移、滞留特点及其在舱室内的分布。计算结果表明:二回路蒸汽管道会发生超压失效,氢燃导致堆舱邻舱的超压失效。至计算结束,约占累积总量99.61%的Xe和49.96%的CsI从堆芯释放出来。舱室Ⅰ和Ⅱ内Xe的分布份额分别为38%和18%,CsI的分布份额分别为22.2%和2.7%,CsI主要存在于舱底水池中,且泄漏至舱室Ⅱ的份额微少。本文分析结果可为进一步的源项剂量分析及船内外应急提供依据。

  10. Batteries'Usability Study in Station Blackout (SBO) for QinShan Nuclear Power Phase II Extension Project%秦山二期扩建核电厂全厂断电(SBO)事故下蓄电池可用性研究

    Institute of Scientific and Technical Information of China (English)

    游洲; 韩勇; 刘文静; 李朋

    2015-01-01

    Station Blackout (SBO) indicates the all AC power supply lost on the emergency and non-emergency bus in the nuclear power plant. In SBO period, batteries' usability is vital for the nuclear power plant to deal with this fault. This paper introduces the way to use batteries, the calculation and analysis of the power supply time in SBO accident. Some suggestions are given for how to deal with SBO.%全厂断电(SBO)是指核电厂完全丧失应急以及非应急母线上的交流电源。全厂断电后,核电厂蓄电池组的可用性成为整个核电厂应对该事故的关键。对秦山二期扩建工程的蓄电池组在SBO事故下的投用方式进行了介绍,对其带载时间进行了计算和分析,就应对SBO事故提出了建议。

  11. Station Blackout Severe Accident Analysis of Spent Fuel Pool of 600 MWe NPP by Using MELCOR Code%用 MELCOR 程序分析600 MWe 核电厂乏燃料水池失去厂内外电源严重事故

    Institute of Scientific and Technical Information of China (English)

    张应超; 季松涛; 魏严凇; 史晓磊; 许倩

    2016-01-01

    Using MELCOR code ,the spent fuel pool (SFP) of 600 MWe nuclear power plant (NPP) was modeled ,and the station blackout severe accidents were calculated when the SFP was under normal condition ,refuelling condition and the reactor accident condition .The calculation results show that fuel assemblies will melt down and hydro‐gen will generate ,due to zirconium‐water reaction ,after the half height of fuel assem‐blies is uncovered .The influence of injection or spray on SFP accidents was analysed , and the results show that SFP accidents will be terminated and the water level of SFP will return up before fuel cladding damage if water is injected or sprayed into the SFP with the boiling evaporation mass rate .%利用MELCOR程序建立了600 MWe核电厂乏燃料水池计算模型,分别计算了在正常储存、正常换料和反应堆事故工况下,乏燃料水池失去厂内外电源严重事故序列。计算结果表明,燃料组件大约裸露一半后,锆水反应导致燃料熔化并产生大量氢气。分析了喷淋和注水对乏燃料水池事故的影响,分析结果表明,在燃料包壳失效前,以沸腾蒸发速率注水或喷淋能中止事故发展,并能使乏燃料水池水位缓慢回升。

  12. Source Term Analysis in Severe Accident Induced by Large Break Loss of Coolant Accident Coincident With Ship Blackout for Ship Reactor%船用堆大破口失水叠加全船断电严重事故源项分析

    Institute of Scientific and Technical Information of China (English)

    张彦招; 张帆; 赵新文; 郑映峰

    2013-01-01

    以某船用压水堆为研究对象,采用M ELCOR程序建立事故分析模型,研究大破口失水事故叠加全船断电严重事故下放射性裂变产物的行为,着重分析了惰性气体和CsI的释放、迁移、滞留特点及在堆舱内的分布。结果表明,83.12%惰性气体从堆芯释放出来,并主要存在于堆舱的气空间;83.08%的CsI从堆芯释放出来,其中,72.66%滞留在堆坑熔融物与一回路内,27.34%释放到堆舱内,并主要溶解于舱底水池中。本文分析结果可为舱室剂量评估、核应急管理提供依据。%Using MELCOR code ,the accident analysis model was established for a ship reactor .The behaviors of radioactive fission products were analyzed in the case of severe accident induced by large break loss of coolant accident coincident with ship blackout . The research mainly focused on the behaviors of release ,transport ,retention and the final distribution of inert gas and CsI . T he results show that 83.12% of inert gas releases from the core , and the most of inert gas exists in the containment . About 83.08% of CsI release from the core ,72.66% of w hich is detained in the debris and the primary system ,and 27.34% releases into the containment . The results can give a reference for the evaluation of cabin dose and nuclear emergency management .

  13. 47 CFR 76.111 - Cable sports blackout.

    Science.gov (United States)

    2010-10-01

    ... zone of a television broadcast station licensed to a community in which a sports event is taking place... station licensed to the community in which the sports event is taking place, the applicable specified zone shall be that of the television station licensed to the community with which the sports event or team...

  14. 47 CFR 76.127 - Satellite sports blackout.

    Science.gov (United States)

    2010-10-01

    ... rights to a sports event, or its agent, no satellite carrier shall retransmit to subscribers within the...” carrying the live television broadcast of a sports event if the event is not available live on a television... television station licensed to the community in which the sports event is taking place, the...

  15. Extended Station Blackout Coping Capabilities of APR1400

    Directory of Open Access Journals (Sweden)

    Sang-Won Lee

    2014-01-01

    Full Text Available The Fukushima Dai-ichi nuclear power plant accident shows that an extreme natural disaster can prevent the proper restoration of electric power for several days, so-called extended SBO. In Korea, the government and industry performed comprehensive special safety inspections on all domestic nuclear power plants against beyond design bases external events. One of the safety improvement action items related to the extended SBO is installation of external water injection provision and equipment to RCS and SG. In this paper, the extended SBO coping capability of APR1400 is examined using MAAP4 to assess the effectiveness of the external water injection strategy. Results show that an external injection into SG is applicable to mitigate an extended SBO scenario. However, an external injection into RCS is only effective when RCS depressurization capacity is sufficiently provided in case of high pressure scenarios. Based on the above results, the technical basis of external injection strategy will be reflected on development of revised severe accident management guideline.

  16. A Distributed Generation-Based Local Self-Recovery Scheme for Distribution Network at Post-Blackout Early Stage of Power Grid Restoration%大停电后初期基于分布式电源的配电网局部自我恢复方案

    Institute of Scientific and Technical Information of China (English)

    谢夏慧; 汪沨; 卢鸣凯; 陈春; 陈奇朋; 曹一家; 董旭柱

    2013-01-01

      分布式电源(distributed generation,DG)具有启动速度快、结构简单、反应灵活等特点,在配电网黑启动中发挥着重要作用。分析了在电网大面积停电情况下基于DG的配电网局部自我恢复方案。因DG的发电功率不能满足配电网中所有负荷的供电,首先在主网分区恢复方案下,根据DG的性能和重要负荷的分布对配电网进行划分;然后讨论了分区后DG启动顺序及恢复路径的优化,以保证能够在尽可能短的时间内恢复尽可能多的重要负荷。该方法以最小路径权值和最大重要负荷恢复量为目标,满足负荷的恢复量不超过DG发电量等约束条件,采用改进粒子群算法进行求解。算例结果验证了该方法的有效性。%  In view of its advantages in fast start-up, simple structure and flexible response, distributed generation (DG) plays an important role in the black start of distribution network. A DG-based local self-recovery scheme for distribution network at post-blackout early stage of power grid restoration is analyzed. Since the DG cannot meet the demand of supplying all loads in distribution network, firstly under the partition recovery scheme of main grid the distribution network is partitioned according to the performance of DG and the distribution of essential loads; secondly the starting sequence of DG after the partitioning and the optimization of the restoration path are discussed to ensure that the power supply for as many as possible loads can be recovered within as short time period as possible. In the proposed model, in which the weight of minimum path and restoration of power supply for maximum essential loads are taken as objectives and the recovered power supply for loads not exceeding the generating capacity of DG is taken as one of constraints, is solved by the modified particle swarm optimization (MPSO). Simulation results of IEEE 33-bus system show that the proposed method is

  17. Anatomy of power system blackouts and preventive strategies by rational supervision and control of protection systems

    Energy Technology Data Exchange (ETDEWEB)

    Phadke, A.G. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States); Horowitz, S.H.; Thorp, J.S.

    1995-01-01

    This report establishes the concept of hidden failures in relays and associated devices used for the protection of electric power systems. A hidden failure is a defect such as a component failure, inappropriate setting or incorrect external connection that remains undetected until some other system event causes the hidden failure to initiate a cascading outage. Associated with the study of hidden failures, this report examines the impact such defects might have by defining regions of vulnerability. A region of vulnerability is the area of the system in which a hidden failure will be activated. To determine such areas we have established criteria associated with load flows and steady-state stability, such as lack of convergence, and employed a technique known as importance sampling in which the simulation is done with the probabilities altered so that the rare event happens more frequently. Our purpose is to provide a framework for further research into relay vulnerability, possibly using adaptive techniques to eliminate hidden defects. We believe control strategies can be developed to prevent cascading normal operations from developing into severe outages by extending the present criteria using steady-state stability and load flow studies into the area of transient stability, and further research into importance sampling would provide significant benefits in evaluating corrective actions.

  18. Structure of a scheme of emergency control to avoid blackout due to interconnection lines loss

    Energy Technology Data Exchange (ETDEWEB)

    Luz, L.T. da; Werberich, L.C.; Herve, H.M. [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul (CEEE), Porto Alegre, RS (Brazil)

    1994-12-31

    This work presents the structure of Gravatai Emergency Control Scheme (ECS) with short about its development and operation. This ECS was made to avoid two kinds of problems for the systems of Companhia Estadual de Energia Eletrica (CEEE). The first one is the voltage collapse that happens after the opening of one of the 525 kv LTs of the interconnection with the Brazilian Interconnected System (BIS). The second one is the CEEE isolating after the 525 kV network loss. We show the ECS existence reason and we describe its functional structure, the substations, the circuits and the amount of load shedding involved by the system. Finally, we present the project of a control structure based on microcomputer which is being developed for this ECS. (author) 3 refs., 11 figs.

  19. Pearl Harbor and America's Homefront Children: First Fears, Blackouts, Air Raid Drills, and Nightmares.

    Science.gov (United States)

    Tuttle, William M., Jr.

    In conducting research about U.S. homefront children during the Second World War, a professor of history wrote to the 100 largest-circulation newspapers in the United States as well as 75 African-American, Hispanic American, and Jewish-American newspapers and magazines seeking letters from people who experienced the War as children. More than…

  20. Tests of Shaft Seal Systems of Circulation Pumps during Station Blackout

    Energy Technology Data Exchange (ETDEWEB)

    Beisiegel, A.; Foppe, F.; Wich, M.

    2014-07-01

    AREVA GmbH operates a unique Thermal-hydraulic plat form in Germany, France and USA. It is recognised as a test body according to ISO 17025. The Deutsche Akkreditierungsstelle GmbH (DAkkS - German Society for Accreditation) has also certified the Thermal-hydraulic platform as an independent inspection body Type C according to ISO 17020. A part of this platform is the Component Laboratory located in Karlstein, Germany which is in operation since more than 50 years. The testing activities cover a wide range as: Critical Heat Flux Tests, Valve Testing and Environmental Qualification for safety related components. Since 2011 the Component Qualification Karlstein extended their testing scope for different types of Shaft Seal Systems. (Author)

  1. Blackout control : proposal of a preventive methodology and its implementation in the Portuguese grid

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, M.M.; Perro, L.L.; Rodrigues, A.C.R. [Rede Electrica Nacional (Portugal)

    2007-07-01

    This paper presented simulation results of the behaviour of the Portuguese electric power transmission grid after the non simultaneous tripping of existing and future natural gas combined-cycle power plants for different load profiles. Of the 62 identified main causes of worldwide major power disturbances, 24 were found to be due to natural events such as fires and storms; 20 were due to failure of primary equipment such as circuit breakers; and, 18 were due to incorrect behaviour of protection systems. A disturbance was classified as a major disturbance if the event had a severity greater then 1 system minute, or if the loss of generation was greater than 10 per cent of peak demand. Seven of these major disturbances have been reported by the Portuguese transmission grid. The tripping of big power plants in Portugal was caused by the loss of multiple grid elements during normal operation of the system. Identifying the main causes of major disturbances offers the possibility of establishing a methodology to prevent major disturbances by simulating the behaviour of the power system under an appropriate set of severe contingencies. This paper described the methodology used to choose the more severe contingencies that should be simulated in the Portuguese transmission grid to help prevent major disturbances. 4 refs., 3 tabs., 5 figs.

  2. Terminal Blackout: Critical Electric Infrastructure Vulnerabilities and Civil-Military Resiliency

    Science.gov (United States)

    2013-10-01

    DANGER Threats to the electric grid (cyber, solar, non-nuclear electromagnetic pulse [NNEMP] and high-altitude nuclear electromagnetic pulse [ HEMP ...issue of massive and cascading loss of the electric grid, emphatically reiterating the dire warnings of the EMP Commission report, in which HEMP ...intentional attack), or on the strength, nature, and direction of an earth-bound CME, smaller electronics—such as those used in transportation and health

  3. A Flooding Induced Station Blackout Analysis for a Pressurized Water Reactor Using the RISMC Toolkit

    Directory of Open Access Journals (Sweden)

    Diego Mandelli

    2015-01-01

    Full Text Available In this paper we evaluate the impact of a power uprate on a pressurized water reactor (PWR for a tsunami-induced flooding test case. This analysis is performed using the RISMC toolkit: the RELAP-7 and RAVEN codes. RELAP-7 is the new generation of system analysis codes that is responsible for simulating the thermal-hydraulic dynamics of PWR and boiling water reactor systems. RAVEN has two capabilities: to act as a controller of the RELAP-7 simulation (e.g., component/system activation and to perform statistical analyses. In our case, the simulation of the flooding is performed by using an advanced smooth particle hydrodynamics code called NEUTRINO. The obtained results allow the user to investigate and quantify the impact of timing and sequencing of events on system safety. In addition, the impact of power uprate is determined in terms of both core damage probability and safety margins.

  4. Optimal blackouts: empirical results on reducing the social cost of electricity outages through efficient regional rationing

    NARCIS (Netherlands)

    de Nooij, M.; Lieshout, R.; Koopmans, C.

    2009-01-01

    The demand and supply of electricity must always balance. If supply falls short of demand, then price increases or voluntary demand reductions might help to maintain the balance in the system. Should these prove insufficient, then rationing is necessary. Rationing means interrupting the electricity

  5. 17 CFR 245.102 - Exceptions to definition of blackout period.

    Science.gov (United States)

    2010-04-01

    ... corporate merger, acquisition, divestiture or similar transaction involving the plan or plan sponsor, the... able to participate in the same class of equity securities after the merger, acquisition,...

  6. 17 CFR 245.101 - Prohibition of insider trading during pension fund blackout periods.

    Science.gov (United States)

    2010-04-01

    ... equity securities in connection with a merger, acquisition, divestiture or similar transaction occurring... from section 306(a)(1) of the Sarbanes-Oxley Act of 2002: (1) Any acquisition of equity securities... acquisition is made pursuant to a plan providing for the regular reinvestment of dividends or interest and...

  7. Modeling of a Flooding Induced Station Blackout for a Pressurized Water Reactor Using the RISMC Toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Mandelli, Diego; Prescott, Steven R; Smith, Curtis L; Alfonsi, Andrea; Rabiti, Cristian; Cogliati, Joshua J; Kinoshita, Robert A

    2011-07-01

    In the Risk Informed Safety Margin Characterization (RISMC) approach we want to understand not just the frequency of an event like core damage, but how close we are (or are not) to key safety-related events and how might we increase our safety margins. The RISMC Pathway uses the probabilistic margin approach to quantify impacts to reliability and safety by coupling both probabilistic (via stochastic simulation) and mechanistic (via physics models) approaches. This coupling takes place through the interchange of physical parameters and operational or accident scenarios. In this paper we apply the RISMC approach to evaluate the impact of a power uprate on a pressurized water reactor (PWR) for a tsunami-induced flooding test case. This analysis is performed using the RISMC toolkit: RELAP-7 and RAVEN codes. RELAP-7 is the new generation of system analysis codes that is responsible for simulating the thermal-hydraulic dynamics of PWR and boiling water reactor systems. RAVEN has two capabilities: to act as a controller of the RELAP-7 simulation (e.g., system activation) and to perform statistical analyses (e.g., run multiple RELAP-7 simulations where sequencing/timing of events have been changed according to a set of stochastic distributions). By using the RISMC toolkit, we can evaluate how power uprate affects the system recovery measures needed to avoid core damage after the PWR lost all available AC power by a tsunami induced flooding. The simulation of the actual flooding is performed by using a smooth particle hydrodynamics code: NEUTRINO.

  8. Depressurization analyses of PWR station blackout with MELCOR 1.8.4

    OpenAIRE

    A.R.Antariksawan; 日高 昭秀; 森山 清史; 橋本 和一郎

    2001-01-01

    PWRの全電源喪失事故(TMLB')では、高圧溶融物放出とそれに続く格納容器直接加熱により格納容器の健全性が脅かされることから、その防止・緩和対策として、一次系強制減圧が推奨されている。また、TMLB'では、一次冷却系ポンプのシール部が冷却不十分のために途中で破損する(ポンプシールLOCA; S3-TMLB')可能性がある。本報では、MELCOR 1.8.4コードを用いて行ったIndian Point 3号炉のTMLB'及びS3-TMLB'とその一次系減圧に関する解析結果について記述する。S3-TMLB'では、ポンプシールの破損タイミングによって事故進展が変化する。TMLB'中に加圧器逃がし弁を開放して減圧した場合の炉心損傷進展は、減圧しない時のそれとほぼ同じとなるが、安全弁も併せて開放すると、事故進展が約6000秒遅れた。...

  9. Steady state load shedding to mitigate blackout in power systems using an improved harmony search algorithm

    Directory of Open Access Journals (Sweden)

    R. Mageshvaran

    2015-09-01

    The proposed algorithm is tested on IEEE 14, 30 and 118 bus test systems. The viability of the proposed method in terms of solution quality and convergence properties is compared with the other conventional methods reported earlier.

  10. Operative and technological management of super-large united power grids: lessons of major world’s blackouts

    Directory of Open Access Journals (Sweden)

    Brinkis K.

    2014-02-01

    Full Text Available Neskatoties uz sasniegumiem elektroenerģētikas jomā un energosistēmu nepārtrauktu modernizāciju, pasaulē regulāri notiek sabrukumu avārijas. Rakstā apskatīti lielu un superlielu energosistēmu apvienību savstarpējas sinhronas darbības nodrošinājuma prasības un kritēriji, kas pamatojas uz operatīvās un tehnoloģiskās vadības ciešu koordināciju starp energosistēmām. Savstarpējas sinhronas darbības nodrošinājuma prasībām un kritērijiem ir izšķiroša nozīme, lai panāktu elektroapgādes drošumu un stabilitāti katrā energosistēmā, kas darbojas apvienotas energosistēmas sastāvā. Šo prasību un kritēriju ievērošana sekmē totālo avāriju izcelšanās iespēju samazināšanu un to novēršanu. Indijas 2012.gada totālo avāriju un citu analogo avāriju Eiropā un Amerikā analīze un izvērtējums laika posmā no 2003.gada, deva iespēju apkopot un izstrādāt lielu un superlielu energosistēmu operatīvās un tehnoloģiskās vadības principus un metodoloģiju, lai novērstu vai ierobežotu totālo avāriju izcelsmes iemeslus.

  11. Foul WX Underground: The Dynamics of Resistance and the Analog Logic of Communication during a Digital Blackout

    Science.gov (United States)

    2009-05-21

    information. 24 Franz Kafka , The Trial (New York: Knopf, 1957). 18 Analysis of the interaction...Press, 1984. Johnson, Steven. Emergence: The Connected Lives of Ants, Brains, Cities, and Software. New York: Scribner, 2001. Kafka , Franz . The...trial and error all too often end up with results more along the lines of Franz Kafka‘s protagonist in The Trial: overwhelmed, under-informed, running

  12. Comparison Study on Thermal-Hydraulic Analysis Depending on Liquid Relief Valve Response for an Station Blackout in CANDU-6

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. M.; Kho, D. W. [KHNP-CRI, Daejeon (Korea, Republic of); Choi, S. H.; Moon, B. J.; Kim, S. R. [Nuclear Engineering Service and Solution Co., Daejeon (Korea, Republic of)

    2014-10-15

    The purpose of this analysis is to compare the results of thermal-hydraulic analysis depending on liquid relief valve response during a station black out (SBO) events in CANDU-6. The primary heat transport system (PHTS) behavior following the postulated SBO is analyzed using CATHENA code. In the paper, analysis was performed to evaluate the effect on coolant system where LRVs are assumed to be opened or opened according to normal open characteristics in the condition of SBO. The result showed that the primary pressure boundary is extended from LRV to DCT and the effects on primary system behavior were neglectable.

  13. 用于GIS抽真空设备的停电报警器%Blackout Alarm Used for GIS Vacuum Equipment

    Institute of Scientific and Technical Information of China (English)

    宋杨; 丁月明; 尹德强; 杨杰; 杜善慧

    2012-01-01

    全封闭组合绝缘GIS设备安装后需要对气室抽真空、氮气和SF6气体,抽真空设备配有涡轮油增压泵,以提高抽真空的功率和真空度.如果发生停电或者设备故障,真空泵就会停机,由于气室的压强接近于真空状态,值班人员如果未能及时关闭抽真空阀门,会发生气室将真空泵的油倒吸进气室内的严重后果.值班人员需要看守多台抽真空设备,同时长时间的值班会使值班人员麻痹大意,不能可靠保证抽真空工作的安全.研制了一种可靠的抽真空设备停电报警装置,采用无源设计,停电后无需额外提供电源,同时安装使用方便.抽真空设备停机后发出声音报警,通过技术手段防止事故的发生,并且能够减轻值班人员的负担,有非常高的实用价值.%The gas chamber needs vacuum, nitrogen and SF6 gas after GIS equipment installation of closed combination insulation, vacuum equipment equips turbine oil booster pump to increase the power and vacuum degree of vacuum. If a power outage or equipment failure, the vacuum pump will be shut down, due to the pressure of the gas chamber close to the vacuum state, the duty officer failed to close the vacuum valve will happen down the gas chamber vacuum pump oil sucked into the serious consequences of the gas chamber. Duty personnel need to guard multiple vacuum equipment, at the same time, personnel will be careless when being on duty for a long time, can not reliably guarantee pumped vacuum work safety. Developed a reliable, vacuum equipment outage alarm device, the use of passive design, it does not additional power supply after power failure, at the same time, installation is easy to use. It will sound alarm after vacuum equipment downtime, through technical means to prevent the occurrence of the accident, and to alleviate the burden of the duty officer, which has very high practical value.

  14. Análisis de la respuesta estructural del edificio de contención de un reactor nuclear PWR frente a una secuencia de Station Blackout

    OpenAIRE

    2013-01-01

    Después del Accidente que sucedió el 11 de marzo de 2011 en la central nuclear de Daichii-Fukushima, han sido muchos los debates reabiertos acerca de la seguridad que ofrecen los reactores nucleares en operación. Debido a las incertidumbres que este accidente ha suscitado, surge ésta tesina, en la que se pretende conocer y comprender técnicamente que sucedería si un accidente similar al de Fukushima ocurriese en uno de los reactores de nuestro país. Con el principal objetivo de encontrar res...

  15. Analysis of Blackout Accident and Mitigation Measure for Small Reactors%小型堆断电严重事故缓解措施分析

    Institute of Scientific and Technical Information of China (English)

    陈航; 张帆; 晏峰; 王坤

    2015-01-01

    以典型的小型堆为研究对象,用MELCOR程序对满功率运行的小型堆全部电源丧失严重事故序列进行计算,分析比较几种缓解措施对事故缓解的作用.结果表明:在发生全部电源丧失后,反应堆热阱丧失,并会发生高压熔堆事故,导致安全壳的完整性受到破坏.若应急电源及时恢复,安全注入系统投入,再循环取海水冷却能有效缓解事故进程.

  16. Analysis of Station Blackout Accident for Subcritical Energy Reactor%次临界能源堆全厂断电事故研究

    Institute of Scientific and Technical Information of China (English)

    张大彬; 解衡; 周志伟

    2015-01-01

    针对次临界能源堆包层燃料结构,修改了MELCOR程序堆芯导热模型,建立次临界能源包层及其冷却回路的严重事故分析模型.在验证了建模方法合理性的基础上,用MELCOR程序开展全厂断电事故导致的严重事故响应特性研究.计算结果表明:包层燃料区功率密度越高,裸露时间越早,燃料熔化越快;内包层上部燃料区域首先出现熔化,外包层熔化时间稍晚,且熔化都发生在所在区域裸露2h以后;锆水反应对事故进程影响明显,部分燃料区域锆水反应释热成为燃料温度持续升高甚至熔化的主要热源.

  17. Preliminary Assessment of the Possible BWR Core/Vessel Damage States for Fukushima Daiichi Station Blackout Scenarios Using RELAP/SCDAPSIM

    Directory of Open Access Journals (Sweden)

    C. M. Allison

    2012-01-01

    Full Text Available Immediately after the accident at Fukushima Daiichi, Innovative Systems Software and other members of the international SCDAP Development and Training Program started an assessment of the possible core/vessel damage states of the Fukushima Daiichi Units 1–3. The assessment included a brief review of relevant severe accident experiments and a series of detailed calculations using RELAP/SCDAPSIM. The calculations used a detailed RELAP/SCDAPSIM model of the Laguna Verde BWR vessel and related reactor cooling systems. The Laguna Verde models were provided by the Comision Nacional de Seguridad Nuclear y Salvaguardias, the Mexican nuclear regulatory authority. The initial assessment was originally presented to the International Atomic Energy Agency on March 21 to support their emergency response team and later to our Japanese members to support their Fukushima Daiichi specific analysis and model development.

  18. Failure analysis on China power grid based on power law

    Institute of Scientific and Technical Information of China (English)

    Xiaofeng WENG; Yiguang HONG; Ancheng XUE; Shengwei MEI

    2006-01-01

    This paper is concerned with the mechanism of blackouts in China power system from the viewpoint of self-organized criticality. By using two estimation algorithms of scaled window variance (SWV) and rescaled rangestatistics (R/S), this paper studies the blackout data in China power system during 1988-1997. The result of analysis shows that the blackout data of 1994-1997 coincides well with the autocorrelation. Furthermore, it is found that the function of blackout probability vs. blackout size exhibits power law distribution.

  19. 巴西"11·10"大停电事故分析及启示%Analysis and Lessons of the Blackout in Brazil Power Grid on November 10, 2009

    Institute of Scientific and Technical Information of China (English)

    林伟芳; 孙华东; 汤涌; 卜广全; 印永华

    2010-01-01

    2009年11月10日,巴西发生了大规模停电事故.结合巴西国家电力系统运行局的官方调查报告,详细介绍事故前巴西电网的运行情况、事故的起因、发展和恢复过程,分析总结事故的教训和经验,并结合中国电网实际,提出保障中国电网安全稳定运行、防止大停电事故发生的建议.

  20. 韶关电网一次停电事故分析及其技术改造优化方案研究%An analysis of blackout of Shaoguan power grid and research on technical reconstruction optimization scheme

    Institute of Scientific and Technical Information of China (English)

    柳玉波; 甄卫国; 余涛

    2011-01-01

    The optimal configuration of busbar automatic transfer switch (BATS) plays an important role in improving the reliability of power supply in a regional power grid.Taking the outage of Mojiang in Shaoguan power grid as an example, the operating characteristics of the power grid before and after the outage and the cause of the accident are analyzed by using BPA transient stability analysis program.The optimization scheme for improving the reliability of power supply in power grid is analyzed.Action logic and control strategy for BATS of the Mojiang station are designed.The dynamic simulation results show that the proposed scheme is feasible, which can make the power grid recover rapidly under the same fault in different operation modes, and make voltage and frequency recover to the acceptable operating range.The proposed scheme can effectively improve the reliability of power supply.%变电站备自投装置的优化配置对于一个地区电网的供电可靠性的提高作用显著.以韶关电网墨江片一起停电事故为例,应用BPA暂态稳定分析程序,分析了事故前后电网的运行特点及失电原因,研究了提高变电站供电可靠性的优化方案,针对该站的特殊情况设计备自投装置的动作逻辑和控制策略.动态仿真分析结果显示,所提方案使电网在同样事故条件,在不同运行方式下均能有效快速恢复片区供电,电压及频率恢复稳定至正常运行范围内,提高了电网的供电可靠性,方案可行.

  1. Clinical Study of Cardiac Sudden Blackouts Cardioversion Caused by Acute Myocardial Infarction%急性心肌梗死致心脏骤停电复律临床研究

    Institute of Scientific and Technical Information of China (English)

    张敏

    2014-01-01

    Objective To study the basic hospital caused by cardiac ar est, acute myocardial infarction (SCA) first aid measures. Methods The clinical data were retrospectively analyzed by recovery in the heart and lung of acute myocardial infarction in 19 cases of cardiac ar est caused by the. Results 19 cases with immediate defibril ation restoration of sinus rhythm, 17cases were cured, 1 cases improved, the total ef ective rate was 89%.Conclusion Immediate electric defibril ation in treatment of acute myocardial infarction and sudden cardiac ar est caused is the most crucial step.%目的研究因心脏骤停引起的急性心肌梗死的的急救措施。方法通过对19例急性心肌梗死引起的心脏骤停进行心肺复苏的临床资料回顾性分析。结果19例立即除颤,17例窦性心律恢复,总有效率达89%。结论立即实施电除颤在急性心肌梗死后心脏骤停的抢救中是最关键的一步。

  2. Calculation of Fission Product Behaviour in a Station Blackout Accident of Daya Bay Nuclear Power Plant%大亚湾核电厂全厂"断电"事故裂变产物行为计算

    Institute of Scientific and Technical Information of China (English)

    郎明刚; 高祖瑛; 周志伟; 奚树人

    2002-01-01

    使用 MELCOR 程序模拟大亚湾核电厂假想全厂断电事故早期进程,计算出安全壳内源项的最大存量,同KORIGEN 程序结合推导出安全壳内主要裂变产物的活性,为核电厂PSA 分析提供保守性数据.

  3. 秦山Ⅰ期核电厂全厂断电事故源项研究%Study on Source Terms in Station Blackout Accident of Qinshan-Ⅰ Nuclear Power Plant

    Institute of Scientific and Technical Information of China (English)

    樊申; 张应超; 季松涛

    2006-01-01

    利用MELCOR程序分析秦山Ⅰ期核电厂全厂断电事故进程中放射性裂变产物的行为,研究不同性质的裂变产物各自的释放、迁移和最终分布状况.同时计算了向环境释放的源项.这些数据可用于事故的厂外后果评价.

  4. Analysis of Natural Circulation and Creep Damage under Station Blackout Severe Accidents%全厂断电严重事故自然循环和蠕变失效分析

    Institute of Scientific and Technical Information of China (English)

    向清安; 邓纯锐; 陈宝文; 冯进军

    2014-01-01

    使用MELCOR 2.1程序建立ACP1000自然循环模型,选取全厂断电叠加辅助给水丧失严重事故(TMLB'),分析主冷却剂管道热段和蒸汽发生器(SG)传热管自然循环现象,采用蠕变失效模型评价主冷却剂系统(RCS)部件失效时间.结果表明,压力容器(RPV)出口接管比有裂纹的SG最热传热管先失效.

  5. Analysis of Off-Site Consequence in Case of Station Blackout Accident for Qinshan Nuclear Power Plant%秦山核电厂全厂断电事故厂外后果分析

    Institute of Scientific and Technical Information of China (English)

    樊申; 谢建伦; 张应超

    2006-01-01

    采用MELCOR和MACCS程序对秦山核电厂全厂断电事故的源项和厂外后果进行计算.该事故将引起厂外群体受到较大剂量的放射性照射,但辐照剂量不足以引发早期确定性健康效应.对可能采取的应急防护行动进行评估,确定最佳防护措施为:安全壳泄漏阶段实施隐蔽;若安全壳超压失效无法避免,应急计划区内应立即实施撤离.

  6. Test Study on Safety Features of Station Blackout Accident for Nuclear Main Pump%断电事故对核主泵安全特性影响的试验研究

    Institute of Scientific and Technical Information of China (English)

    刘夏杰; 刘军生; 王德忠; 杨哲; 张继革

    2009-01-01

    介绍了国内外反应堆冷却剂泵在发生各种事故情况下的理论及试验研究情况,针对核主泵断电惰转过程中的瞬态水力特性进行了试验研究,对试验结果进行了讨论.介绍了用于断电试验的试验设备及试验方法,着重分析了惰转过程中流量、转速、振动参数,并用四次多项式拟合的方法模拟惰转过程的流量、转速随时间的变化.试验结果表明:在断电瞬间,泵的流量和转速迅速下降,试验结果符合安全标准规定;轴承座位移振动在断电瞬间突然加强,在断电后一段时间转轴振动才发生变化.试验和分析结果有助于认识核主泵发生全厂断电事故时的水力特性,为核主泵的安全评价提供基础依据.

  7. Blackout Start Test of North China Power Network Using Pumped storage Power Units in Ming Tombs%华北电网利用十三陵水电机组进行黑启动试验研究

    Institute of Scientific and Technical Information of China (English)

    雷为民; 刘永奇; 王海忠; 费维刚

    2001-01-01

    在电网全部停电恶劣情况下快速恢复供电对华北电网尤显重要.介绍结合华北电网尤其是北京电网特点,在计算分析、周密安排、各有关单位编制详细执行方案基础上,进行实际系统黑启动试验时有关调度方面所进行的工作.试验的成功说明北京十三陵蓄能电厂经过91 km长的220 kV临时经多站组合线路可顺利启动北京石景山热电厂200 MW火电机组.

  8. Cascading Failure Risk Variation with Generator Dispatch and System Load Level

    CERN Document Server

    Rezaei, Pooya

    2013-01-01

    Industry reliability rules increasingly require utilities to study and mitigate cascading failure risk in their system. Motivated by this, this paper describes how cascading failure risk, in terms of expected blackout size, varies with power system load level and pre-contingency dispatch. We used Monte Carlo sampling of random branch outages to model contingencies, and a model of cascading failure to estimate blackout sizes. The risk associated with different blackout sizes is separately estimated in order to separate small, medium, and large blackout risk. Results from N-1 secure models of the IEEE RTS case and a 2383 bus case indicate that blackout risk does not always increase with load level, particularly for large blackout risk. The results also show that risk is highly dependent on the method used for generator dispatch. Minimum cost methods of dispatch can result in larger long distance power transfers, which can increase cascading failure risk.

  9. Prospects of Studies on Application of Complex System Theory in Power Systems

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Over the last decade, power systems in the world have suffered a number of blackouts caused by cascading failures. Such incidents resulted in major economic losses and social impacts, induced great concerns on the grid security and prompted people to understand and analyze the mechanism of the power system's cascading failures and blackouts. Conventional analysis on power systems constructs a detailed model of every component of the system, and focuses on dynamic behaviors of individual components. Therefore, it is difficult to uncover the global dynamic characteristic while deeply studying the cascading failures and the mechanism of large blackouts. The complex system theory can provide global perspectives of cascading blackouts.

  10. Development of Early Warning Methods for Electric Power Systems

    DEFF Research Database (Denmark)

    Jóhannsson, Hjörtur

    This thesis concerns the development of methods that can provide, in realtime, an early warning for an emerging blackout in electric power systems. The blackout in E-Denmark and S-Sweden on September 23, 2003 is the main motivation for the method development. The blackout was caused by occurrence...... methods, that could, in such situations, give an early warning for the emerging blackout. After investigation of data and plots taken from the time of the blackout, it was decided to focus the development on assessment of aperiodic small signal stability. In order to assess the system generators aperiodic...... small signal stability, expressions for stability boundaries were algebraically derived in the injection impedance plane. A method for detecting aperiodic small signal stability was established, which was based on one of the derived boundaries. The method carries out an element-wise assessment...

  11. Analysis of a Power System Blackout Incident Caused by Busbar Automatic Transfer Switch (BATS)Device Operation Failure%一起备自投装置拒动引起的电网大面积停电事件分析

    Institute of Scientific and Technical Information of China (English)

    孙广通

    2015-01-01

    A power outage incident occurred in Zengcheng,Guangzhou was introduced,and its cau-ses and development process was analyzed in detail.Some countermeasures and suggestions were put forward aiming at this incident,both to prevent such ones from happening again,and to provide valu-able references for power grids with similar operation mode at high risk.%介绍了发生在广州增城地区的一起大面积停电事件,并对这起事件的原因和发展过程进行了分析,针对此次事件提出了相应的对策和建议,对有类似运行方式的高风险电网具有一定预警作用和参考价值。

  12. Plaadid / Tui Hirv

    Index Scriptorium Estoniae

    Hirv, Tui, 1984-

    2007-01-01

    Uutest heliplaatidest Andrea Bocelli "Vivere. The Best Of", Britney Spears "Blackout", John Fogerty "Revival", Bat For Lashes "Fur And Gold", Jimmy Eat World "Chase This Light", Duran Duran "Red Carpet Massacre"

  13. Development of a thermal prediction model and flight data evaluation and comparison for the EOB experiment of the HELIOS solar probe

    Science.gov (United States)

    Kramp, K.; Ley, W.; Schmidt, H. P.

    1975-01-01

    A thermal model for the EOB experiment has been developed, adopted to test data, and used to predict flight temperatures. These predictions are compared to flight data covering the period from launch until the first black-out.

  14. Dispersed Trading and the Prevention of Market Failure

    DEFF Research Database (Denmark)

    Porter, David C.; Tanggaard, Carsten; G. Weaver, Daniel

    With augmented demands on power grids resulting in longer and larger blackouts combined with heightened concerns of terrorist attacks, trading institutions and policy makers have widened their search for systems that avoid market failure during these disturbing events. We provide insight into thi......With augmented demands on power grids resulting in longer and larger blackouts combined with heightened concerns of terrorist attacks, trading institutions and policy makers have widened their search for systems that avoid market failure during these disturbing events. We provide insight...... into this issue by examining trading behavior at the Copenhagen Stock Exchange during a major blackout. We find that although market quality declined, markets remained functional and some price discovery occurred during the blackout period suggesting that the NOREX structure of interlinked trading systems...... combined with widely dispersed trading locations may be a viable means of protection against market failure during massive power disruptions or terrorist attacks....

  15. Dispersed trading and the prevention of market failure

    DEFF Research Database (Denmark)

    Porter, David C.; Tanggaard, Carsten; Weaver, Daniel G.

    2008-01-01

    With augmented demands on power grids resulting in longer and larger blackouts combined with heightened concerns of terrorist attacks, trading institutions and policy makers have widened their search for systems that avoid market failure during these disturbing events. We provide insight into thi......With augmented demands on power grids resulting in longer and larger blackouts combined with heightened concerns of terrorist attacks, trading institutions and policy makers have widened their search for systems that avoid market failure during these disturbing events. We provide insight...... into this issue by examining trading behaviour at the Copenhagen Stock Exchange during a major blackout. We find that although market quality declined, markets remained functional and some price discovery occurred during the blackout period suggesting that the NOREX structure of interlinked trading systems...... combined with widely dispersed trading locations may be a viable means of protection against market failure during massive power disruptions or terrorist attacks....

  16. Integration of wind power for optimal power system black-start restoration

    OpenAIRE

    ZONKOLY, AMANY EL

    2015-01-01

    Integration of wind farms into power systems may increase the risk of power system blackouts due to the uncertain nature of their output power. In the meantime, wind turbines have relatively short starting time when compared to non-black-start (NBS) generating units. For this reason, wind farms need to participate in power system restoration after blackouts. The decision of restoring a wind farm depends on its output power and the characteristics of the power system. The power system restorat...

  17. Vegetation Height Estimation Near Power transmission poles Via satellite Stereo Images using 3D Depth Estimation Algorithms

    OpenAIRE

    Qayyum, A; A. S. Malik; Saad, M. N. M.; Iqbal, M.; F. Abdullah; W. Rahseed; T. A. R. B. T. Abdullah; A. Q. Ramli

    2015-01-01

    Monitoring vegetation encroachment under overhead high voltage power line is a challenging problem for electricity distribution companies. Absence of proper monitoring could result in damage to the power lines and consequently cause blackout. This will affect electric power supply to industries, businesses, and daily life. Therefore, to avoid the blackouts, it is mandatory to monitor the vegetation/trees near power transmission lines. Unfortunately, the existing approaches are more t...

  18. ASCERTAINMENT OF ELECTRIC-SUPPLY SCHEMES RELIABILITY FOR THE ATOMIC POWER PLANT AUXILIARIES

    Directory of Open Access Journals (Sweden)

    A. L. Starzhinskij

    2015-01-01

    Full Text Available The paper completes ascertainment of electrical-supply scheme reliability for the auxiliaries of a nuclear power plant. Thereat the author considers the system behavior during the block normal operation, carrying out current maintenance, and capital repairs in combination with initiating events. The initiating events for reactors include complete blackout, i.e. the loss of outside power supply (normal and reserve; emergency switching one of the working turbogenerators; momentary dumping the normal rating to the level of auxiliaries with seating the cutout valve of one turbo-generator. The combination of any initiating event with the repairing mode in case of one of the system elements failure should not lead to blackout occurrence of more than one system of the reliable power supply. This requirement rests content with the help of the reliable power supply system self-dependence (electrical and functional and the emergency power-supply operational autonomy (diesel generator and accumulator batteries.The reliability indicators of the power supply system for the nuclear power plant auxiliaries are the conditional probabilities of conjoined blackout of one, two, and three sections of the reliable power supply conditional upon an initiating event emerging and the blackout of one, two, and three reliable power-supply sections under the normal operational mode. Furthermore, they also are the blackout periodicity of one and conjointly two, three, and four sections of normal operation under the block normal operational mode. It is established that the blackout of one bus section of normal operation and one section of reliable power-supply system of the auxiliaries that does not lead to complete blackout of the plant auxiliaries may occur once in three years. The probability of simultaneous power failure of two or three normal-operation sections and of two reliable power-supply sections during the power plant service life is unlikely.

  19. Analysis of Chain of Events in Major Historic Power Outages

    Directory of Open Access Journals (Sweden)

    HUANG, T.

    2014-08-01

    Full Text Available Contemporary power systems are facing increasing intricate conditions that have never been considered when initially designing the infrastructure, such as malicious threats, accommodating smart grids, etc. As a consequence, blackouts albeit seldom but stubbornly keep appearing from time to time the world around, and demonstrate their devastating capability to create vast damage on both power systems and the society at large. Patterns of the blackout starting from the first triggering events to the system final status have emerged. A framework of a coding system was proposed in this paper in order to capture the common feature in the system evolution during the development of cascades. Cascades in a blackout can be tracked by a chain of events with the help of the codes. It is facile to adopt the framework to build up a knowledge base of blackouts. By applying the proposed framework to 31 selected historic blackouts, most frequent events, effects and origins are identified; the findings can provide useful information for grid designers and security experts for ranking the most imminent issues in their study.

  20. Estimating Cascading Failure Risk with Random Chemistry

    CERN Document Server

    Rezaei, Pooya; Eppstein, Margaret J

    2014-01-01

    The potential for cascading failure in power systems adds substantially to overall reliability risk. Monte Carlo sampling can be used with a power system model to estimate this impact, but doing so is computationally expensive. This paper presents a new approach to estimating the risk of large cascading blackouts triggered by multiple contingencies. The method uses a search algorithm (Random Chemistry) to identify blackout-causing contingencies, and then combines the results with outage probabilities to estimate overall risk. Comparing this approach with Monte Carlo sampling for two test cases (the IEEE RTS-96 and a 2383 bus model of the Polish grid) suggests that the new approach is at least two orders of magnitude faster than Monte Carlo, without introducing measurable bias. Moreover, the approach enables one to compute the contribution of individual component-failure probabilities to overall blackout risk, allowing one to quickly identify low-cost strategies for reducing risk. By computing the sensitivity ...

  1. Severe accident source term characteristics for selected Peach Bottom sequences predicted by the MELCOR Code

    Energy Technology Data Exchange (ETDEWEB)

    Carbajo, J.J. [Oak Ridge National Lab., TN (United States)

    1993-09-01

    The purpose of this report is to compare in-containment source terms developed for NUREG-1159, which used the Source Term Code Package (STCP), with those generated by MELCOR to identify significant differences. For this comparison, two short-term depressurized station blackout sequences (with a dry cavity and with a flooded cavity) and a Loss-of-Coolant Accident (LOCA) concurrent with complete loss of the Emergency Core Cooling System (ECCS) were analyzed for the Peach Bottom Atomic Power Station (a BWR-4 with a Mark I containment). The results indicate that for the sequences analyzed, the two codes predict similar total in-containment release fractions for each of the element groups. However, the MELCOR/CORBH Package predicts significantly longer times for vessel failure and reduced energy of the released material for the station blackout sequences (when compared to the STCP results). MELCOR also calculated smaller releases into the environment than STCP for the station blackout sequences.

  2. Handbook of electrical power system dynamics modeling, stability, and control

    CERN Document Server

    Eremia, Mircea

    2013-01-01

    Complete guidance for understanding electrical power system dynamics and blackouts This handbook offers a comprehensive and up-to-date treatment of power system dynamics. Addressing the full range of topics, from the fundamentals to the latest technologies in modeling, stability, and control, Handbook of Electrical Power System Dynamics provides engineers with hands-on guidance for understanding the phenomena leading to blackouts so they can design the most appropriate solutions for a cost-effective and reliable operation. Focusing on system dynamics, the book details

  3. MATCASC: A tool to analyse cascading line outages in power grids

    CERN Document Server

    Koç, Yakup; Araujo, Nuno A M; Warnier, Martijn

    2013-01-01

    Blackouts in power grids typically result from cascading failures. The key importance of the electric power grid to society encourages further research into sustaining power system reliability and developing new methods to manage the risks of cascading blackouts. Adequate software tools are required to better analyze, understand, and assess the consequences of the cascading failures. This paper presents MATCASC, an open source MATLAB based tool to analyse cascading failures in power grids. Cascading effects due to line overload outages are considered. The applicability of the MATCASC tool is demonstrated by assessing the robustness of IEEE test systems and real-world power grids with respect to cascading failures.

  4. Saving electricity in a hurry. Dealing with temporary shortfalls in electricity supplies

    Energy Technology Data Exchange (ETDEWEB)

    none

    2005-07-01

    Blackouts are normally the result of imbalances in electricity supply and demand. A brief blackout is mostly an inconvenience. But persistent shortfalls ? those lasting days, weeks, or months ? can cause economic disruption and danger to human life in our technology-rich societies. Saving Electricity in a Hurry describes some of the recent power shortfalls, from Norway to New Zealand, from Tokyo to Arizona and the policies these regions used to quickly reduce their power consumption. How did the whole country of Sweden cut its power consumption by 4% in only three days? How did California save 14% in only a few months? While the temporary shortfalls in electricity supplies described in this book are relatively rare events, they disproportionately shape future energy policies. Saving Electricity in a Hurry shows that countries can quickly reduce electricity consumption without harming the economy as much as blackouts or unplanned curtailments. The strategies are diverse, unique and often surprisingly cheap. They include mass media campaigns ? where a good joke can save a Megawatt ? improvements in equipment efficiency and quickly adjusting electricity prices. This book explains how California replaced a million traffic signals with energy-saving models, how millions of Tokyo residents raised their thermostat settings, and how New Zealanders took shorter showers, all quickly enough to help avoid imminent blackouts. Finally, it connects these policies to the traditional goal of ?saving electricity slowly?.

  5. A True Lifeline

    Institute of Scientific and Technical Information of China (English)

    LAN XINZHEN

    2010-01-01

    @@ Chenzhou,a medium-sized city in Hunan Province,knows what it's like to be cut off from the rest of the world.The city suffered a 15-day blackout during a snowstorm in 2008 in south China when power supply was disrupted and many trains were delayed.

  6. 77 FR 16483 - Petition for Rulemaking Submitted by the Natural Resources Defense Council, Inc.

    Science.gov (United States)

    2012-03-21

    ...; ] NUCLEAR REGULATORY COMMISSION 10 CFR Part 50 Petition for Rulemaking Submitted by the Natural Resources... Natural Resources Defense Council, Inc. (NRDC or the petitioner), in the rulemaking process. The... establish station blackout (SBO) mitigation strategies and resources. The NRC determined that the...

  7. 76 FR 58165 - Petitions for Rulemaking Submitted by the Natural Resources Defense Council, Inc.

    Science.gov (United States)

    2011-09-20

    ..., PRM-50-102; NRC-2011-0189] Petitions for Rulemaking Submitted by the Natural Resources Defense Council... rulemaking (PRM), dated July 26, 2011, from the Natural Resources Defense Council, Inc. (NRDC or the... station blackout mitigation strategies and resources; and more realistic, hands-on training and...

  8. The Mini Dark Room from Holywell High

    Science.gov (United States)

    Lane, Frank

    2011-01-01

    The mini dark room from Holywell High School costs nothing to make and has a construction time of 10 min. In spite of progress, or perhaps because of it, light experiments often have to be performed without blackout. Put this idea into practice and each pupil can have a dark room--and best of all, it's free. In this article, the author describes…

  9. Adaptive Tuning of Frequency Thresholds Using Voltage Drop Data in Decentralized Load Shedding

    DEFF Research Database (Denmark)

    Hoseinzadeh, Bakhtyar; Faria Da Silva, Filipe Miguel; Bak, Claus Leth

    2015-01-01

    Load shedding (LS) is the last firewall and the most expensive control action against power system blackout. In the conventional under frequency LS (UFLS) schemes, the load drop locations are already determined independently of the event location. Furthermore, the frequency thresholds of LS relays...

  10. Electronic Warfare (EW) Historical Perspectives and Its Relationship to Information Operations (IO) - Considerations for Turkey

    Science.gov (United States)

    2006-09-01

    the video to preloaded maps onboard, enabling the missile to cruise over the terrain using reference points. For the first time, chips and computers...intended, was blown toward the land some 90 miles away and draped over electric power lines, shorting the transformers and causing blackouts in

  11. Designing Offshore Super Grid for the Combined Operation of Offshore Wind Farms and Hydro Storage

    DEFF Research Database (Denmark)

    Grimaldi, Armando; Chen, Zhe; Chen, Peiyuan

    2009-01-01

    The European commission decided in 2008 to reduce the dependency of imported primary energy sources and to promote the use of renewable energy. In particular, many offshore wind farms are planned in the North Sea between 2020 and 2030. Furthermore, the recent blackouts in Europe have shown that i...

  12. Optimalisering Ventilationjet systeem

    NARCIS (Netherlands)

    Weel, van P.A.

    2015-01-01

    The Ventilationjet system is used to dehumidify a greenhouse with a fully closed blackout screen during the night. Gerbera producer Zuijderwijk and Witzier in the Netherlands uses this equipment but was not satisified with the duhumidification capacity since the RH was rising to unwanted levels. Tha

  13. Detection of vulnerable relays and sensitive controllers under cascading events based on performance indices

    DEFF Research Database (Denmark)

    Liu, Zhou; Chen, Zhe; Hu, Yanting

    2014-01-01

    The unexpected relay operations have been regarded as one of main reasons to propagate and induce the cascaded blackouts. It is significant to timely detect vulnerable relays to be blocked, and locate sensitive controllers to regulate the emergency states. In this paper, a multi agent system (MAS...

  14. Resource Efficient Scheduling, Optimization and Control.

    NARCIS (Netherlands)

    van den Akker, Marjan; Derksen, Christian; Kowalczyk, Ryszard; Mönch, Lars; Valogianni, Konstantina; van Heck, Erik; Zhang, Minjie

    2014-01-01

    This report documents the program and the outcomes of Dagstuhl Seminar 14181 "Multi-agent systems and their role in future energy grids". A number of recent events (e.g. Fukushima, Japan, and the largest blackout in history, India) have once again increased global attention on climate change and res

  15. ONLINE MONITORING STEADY STATE STABILITY LIMIT PADA SISTEM INTERKONEKSI SULSELRABAR

    OpenAIRE

    2015-01-01

    Pada beberapa dekade terakhir, fenomena black-out (pemadaman total)akibat voltage collapse mengalami peningkatan.Hal ini disebabkan oleh peningkatan konsumen pemakai listrik yang tidak sebanding dengan peningkatan pembangkit dan pengembangan jaringan transmisi. Berdasarkan kenyataan dilapangan, ketidakstabilan steady state sangat berhubungan dengan rendahnya ketersediaan daya aktif/reaktif, level tegangan yang rendah, dan besarnya perubahan tegangan untuk perubahan beban atau daya pembangkit....

  16. Coordinated Agent-Based Control for On-line Voltage Instability Prevention

    NARCIS (Netherlands)

    Baalbergen, J.F.

    2013-01-01

    Service interruptions have a significant impact on society and therefore the main objective of power system planning and operation is to ensure that they do not happen. Because voltage instability is one of the dynamic phenomena that may result in a system-wide blackout, this type of stability probl

  17. Construction of a low cost wind energy generator; Construcao de um gerador de energia eolica de baixo custo

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Jonathan Penha de; Almeida, Silvio Carlos Anibal de [Universidade Federal do Rio de Janeiro (DEM/EP/UFRJ), RJ (Brazil). Escola Politecnica. Dept. de Engenharia Mecanica], Emails: jonathan_penha@poli.ufrj.br, silvioa@gmail.com

    2010-07-01

    This project presents a low cost wind electric power generator constituted of cheap and easy access materials. The necessary materials are presented for it construction and the expected efficiency, having as reference the city of Fernando de Noronha, Brazil. The elaboration of the generator was initially developed as alternative energy source during blackout.

  18. Maternal Nutrition and Four-Alternative Choice

    Science.gov (United States)

    Davison, Michael; Krageloh, Christian U.; Fraser, Mhoyra; Breier, Bernhard H.

    2007-01-01

    Two groups of 10 male rats were trained to nose poke for food pellets at four alternatives that provided differing rates of pellet delivery on aperiodic schedules. After a fixed number of pellets had been delivered, 5, 10 or 20 in different conditions of the experiment, a 10-s blackout occurred, and the locations of the differing rates of pellet…

  19. Structural vulnerability assessment of electric power grids

    NARCIS (Netherlands)

    Koç, Y.; Warnier, M.; Kooij, R.E.; Brazier, F.

    2014-01-01

    Cascading failures are the typical reasons of blackouts in power grids. The grid topology plays an important role in determining the dynamics of cascading failures in power grids. Measures for vulnerability analysis are crucial to assure a higher level of robustness of power grids. Metrics from Comp

  20. The Effects of Time Outs to S-Approaches on Transposition and Peak Shift.

    Science.gov (United States)

    Wildemann, Donald G.; Holland, James G.

    Relational responding and peak shift were found to be related. In two experiments, pigeons were trained to make a successive discrimination by either the blackout method of errorless learning or training with extinction. In experiment 1, pigeons trained with extinction learned a circle-sized discrimination more quickly than pigeons trained with…

  1. Context-independent centrality measures underestimate the vulnerability of power grids

    NARCIS (Netherlands)

    Verma, T.; Ellens, W.; Kooij, R.E.

    2015-01-01

    Power grids vulnerability is a key issue in society. A component failure may trigger cascades of failures across the grid and lead to a large blackout. Within complex network analysis, structural vulnerabilities of power grids have been studied mostly using purely topological approaches, which assum

  2. The Impact of the Topology on Cascading Failures in a Power Grid Model

    NARCIS (Netherlands)

    Koç, Y.; Warnier, M.; Van Mieghem, P.; Kooij, R.E.; Brazier, F.M.T.

    2014-01-01

    Cascading failures are one of the main reasons for large scale blackouts in power transmission grids. Secure electrical power supply requires, together with careful operation, a robust design of the electrical power grid topology. Currently, the impact of the topology on grid robustness is mainly as

  3. Priority One: Environment. The Energy Challenge.

    Science.gov (United States)

    Augis, Lynne; And Others

    This unit is one of a series in environmental education for grades 1-12. The unit is designed to be used with secondary school students and includes the following sections: (1) Preface; (2) Foods, Fuels, and You; (3) Blackout in the City; (4) Conservation and Efficiency; (5) Our Present Sources; (6) The Oil Crisis; (7) The Nculear Controversy; (8)…

  4. 47 CFR 76.123 - Satellite syndicated program exclusivity.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Satellite syndicated program exclusivity. 76... Exclusivity and Sports Blackout § 76.123 Satellite syndicated program exclusivity. (a) Upon receiving notification pursuant to paragraph (d) of this section, a satellite carrier shall not deliver, to...

  5. 47 CFR 76.93 - Parties entitled to network non-duplication protection.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Parties entitled to network non-duplication... RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout § 76.93 Parties entitled to network non-duplication...

  6. 47 CFR 76.95 - Exceptions.

    Science.gov (United States)

    2010-10-01

    ... CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout...-duplication protection against it. (b) Network non-duplication protection need not be extended to a higher... otherwise be required to provide non-duplication protection following the scheduled time of completion....

  7. 47 CFR 76.92 - Cable network non-duplication; extent of protection.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Cable network non-duplication; extent of... RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout § 76.92 Cable network non-duplication; extent of protection....

  8. 47 CFR 76.94 - Notification.

    Science.gov (United States)

    2010-10-01

    ... CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout § 76.94 Notification. (a) In order to exercise non-duplication rights pursuant to § 76.92, television stations shall notify each cable television system operator of the non-duplication sought in...

  9. 47 CFR 76.122 - Satellite network non-duplication.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Satellite network non-duplication. 76.122... MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout § 76.122 Satellite network non-duplication. (a) Upon receiving notification pursuant...

  10. Californian labs feel the heat of the energy crisis

    CERN Multimedia

    Dalton, R B

    2001-01-01

    Laboratories operating for the DOE have been told their power may be shut off for up to two hours at a time. Warmer weather has increased the use of air conditioning and the blackouts are expected to become more frequent over the summer (1/2 page).

  11. 78 FR 18817 - Revisions to Reliability Standard for Transmission Vegetation Management

    Science.gov (United States)

    2013-03-28

    ... many blackouts has been vegetation-related outages. In fact, one of the initiating causes of the 2003... Commission providing the results of the testing.\\8\\ \\5\\ See U.S.-Canada Power System Outage Task Force, Final... prevent outages caused by vegetation intrusion. Likewise, AEP, BPA, Idaho Power, ITC Companies,...

  12. Temporal Causal Diagrams for Diagnosing Failures in Cyber Physical Systems

    Science.gov (United States)

    2014-10-02

    lead to impending fault cascades, which can be avoided (Zhang, Ilic, & Tonguz, 2011; Tholomier, Richards, & Apostolov, 2007). Recent blackouts and hurri ...710-717. doi: 10.1109/61.853009 Console, L., & Torasso, P. (1991). On the co-operation be- tween abductive and temporal reasoning in medical di

  13. 49 CFR 583.6 - Procedure for determining U.S./Canadian parts content.

    Science.gov (United States)

    2010-10-01

    ..., gasoline, oil, blackout, phosphate rinse, windshield washer fluid, fasteners, tire assembly fluid, rivets.... (1) For items of equipment received at the final assembly point, the value is the price paid by the... the final assembly point (but not as part of final assembly), the value is the fair market price...

  14. Stuart Brisley etendused inimliku ja kunstipärase piiril / Andri Ksenofontov

    Index Scriptorium Estoniae

    Ksenofontov, Andri, 1962-

    2009-01-01

    Stuart Brisley näitus "Crossings" ("Ületamised") Tallinna Linnagaleriis 19- sept. - 4. oktoobrini. Heli- ja valgusinstallatsioonist "Touching Black Ice" Titanicu hukkumisest 1912. a. 15. aprillil. Videoinstallatsioonist "Blackout" Estonia hukkumisest 1994. a. 28. septembril. Näitusega kaasnevast kataloogist. Stuart Brisley loomingust

  15. A topological investigation of phase transitions of cascading failures in power grids

    NARCIS (Netherlands)

    Koç, Y.; Warnier, M.; Mieghem, P. van; Kooij, R.E.; Brazier, F.M.T.

    2014-01-01

    Cascading failures are one of the main reasons for blackouts in electric power transmission grids. The economic cost of such failures is in the order of tens of billion dollars annually. The loading level of power system is a key aspect to determine the amount of the damage caused by cascading failu

  16. Eesti elektrisüsteemi juhtimiskeskus kasutab ülimoodsat tehnikat / Raigo Neudorf

    Index Scriptorium Estoniae

    Neudorf, Raigo

    2007-01-01

    Eesti Energia kontserni kuuluva OÜ Põhivõrk juhtimiskeskust Tallinnas Kadaka teel tutvustab elektrisüsteemi juhtimise osakonna juhataja Valeri Peterson. Vt. samas: Blackout välistatud; Häkkerite hammas keskusele peale ei hakka; Küsimusele Põhivõrgu IT-eelarve kohta vastab OÜ Põhivõrk kommunikatsioonijuht Kätlin Kruus

  17. Decentralized planning of energy demand for the management of robustness and discomfort

    NARCIS (Netherlands)

    Pournaras, E.; Vasirani, M.; Kooij, R.E.; Aberer, K.

    2014-01-01

    The robustness of smart grids is challenged by unpredictable power peaks or temporal demand oscillations that can cause blackouts and increase supply costs. Planning of demand can mitigate these effects and increase robustness. However, the impact on consumers in regards to the discomfort they exper

  18. "Musta Peetri" stuudio Nafta näitab uusi lühifilme / Andres Laasik

    Index Scriptorium Estoniae

    Laasik, Andres, 1960-2016

    2010-01-01

    Filmistuudio Nafta lühifilmide kava 1. oktoobrist 2010 Tallinna kinos Artis. Kavasse kuuluvad uued linateosed Heleri Saariku "Näkilugu" ja Margus Paju "Blackout" ning Priit Pääsukese "Must Peeter" (2008), Peeter Sauteri novelli "Must notsu" ekraniseering

  19. Kinos voolab naftat / Tiit Tuumalu

    Index Scriptorium Estoniae

    Tuumalu, Tiit, 1971-

    2010-01-01

    Filmistuudio Nafta lühifilmide kava 1. oktoobrist 2010 Tallinna kinos Artis. Kavasse kuuluvad uued linateosed: Heleri Saariku "Näkilugu" ja Margus Paju "Blackout" ning Priit Pääsukese "Must Peeter" (2008), Peeter Sauteri novelli "Must notsu" ekraniseering

  20. A robustness metric for cascading failures by targeted attacks in power networks

    NARCIS (Netherlands)

    Koc, Y.; Warnier, M.; Kooij, R.E.; Brazier, F.M.T.

    2013-01-01

    Cascading failures are the main reason blackouts occur in power networks. The economic cost of such failures is in the order of tens of billion dollars annually. In a power network, the cascading failure phenomenon is related to both topological properties (number and types of buses, density of tran

  1. Energy systems security

    CERN Document Server

    Voeller, John G

    2014-01-01

    Energy Systems Security features articles from the Wiley Handbook of Science and Technology for Homeland Security covering topics related to electricity transmission grids and their protection, risk assessment of energy systems, analysis of interdependent energy networks. Methods to manage electricity transmission disturbances so as to avoid blackouts are discussed, and self-healing energy system and a nano-enabled power source are presented.

  2. Non-iterative Voltage Stability

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, Yuri V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Vyakaranam, Bharat [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hou, Zhangshuan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wu, Di [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Meng, Da [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Shaobu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elbert, Stephen T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Miller, Laurie E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huang, Zhenyu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-09-30

    This report demonstrates promising capabilities and performance characteristics of the proposed method using several power systems models. The new method will help to develop a new generation of highly efficient tools suitable for real-time parallel implementation. The ultimate benefit obtained will be early detection of system instability and prevention of system blackouts in real time.

  3. Brazil Lightning Bolts Set Shocking World Record

    Institute of Scientific and Technical Information of China (English)

    卞小翩

    2002-01-01

    巴西是世界上最大的地处热带地区的国家,因此,它就成了世界“雷电之国”。让我们吃惊的是,10%of all lightning-rylated deaths in the world竟然发生在巴西!文章出现一个名词词组 power blackouts,而擅长使用词汇connotation的英语也常常“活用”此词。 He had had a blackout after the accident./事故发生后,他晕过去一阵子。

  4. Automatic Synchronization as the Element of a Power System's Anti-Collapse Complex

    Science.gov (United States)

    Barkāns, J.; Žalostība, D.

    2008-01-01

    In the work, a new universal technical solution is proposed for blackout prevention in a power system, which combines the means for its optimal short-term sectioning and automatic self-restoration to normal conditions. The key element of self-restoration is automatic synchronization. The authors show that for this purpose it is possible to use automatic re-closing with a device for synchronism-check. The results of computations, with simplified formulas and a relevant mathematical model employed, indicate the area of application for this approach. The proposed solution has been created based on many-year experience in the liquidation of emergencies and on the potentialities of equipment, taking into account new features of blackout development that have come into being recently.

  5. A Distributed Autonomous Approach for Bulk Power System Restoration by Means of Multi-Agent System

    Science.gov (United States)

    Nagata, Takeshi; Tahara, Yoshiki; Kunisa, Daisuke; Fujita, Hideki

    In recent years, the electric utility industry worldwide has been facing pressure to be deregulated. Along with it, risk of blackout in large area will also increase. Actually, it is still vivid in our memory that the northeastern US and southern Canada suffered the worst blackout in history. Consequently, a method to find the optimal solution rapidly is needed all the more. In this paper, we propose a new multi-agent method for a bulk power system restoration. In order to demonstrate the capability of the proposed multi-agent system, it has been applied to a model bulk power system, which consists of three local areas including twelve generating units and twelve loads, and three remote areas with twelve loads. A large number of simulations are carried out on this model network with changing conditions. The simulation results show that the proposed multi-agent approach is effective and promising.

  6. System Simulation and Implementation of SIPS in Taiwan

    Directory of Open Access Journals (Sweden)

    Chao-Rong Chen

    2014-01-01

    Full Text Available This study describes the system simulation and implementation of the system integrity protection schemes (SIPS in an independent, intensive, and island-type power system. It also elucidates a smart grid plan to provide grid security in this power grid. The proposed SIPS can prevent blackouts that could otherwise result from the transient instability of N-3 contingencies and has been fully implemented and operated. The entire SIPS installation comprises two stages. The first-stage SIPS takes generator tripping system simulation and the second-stage SIPS involves generator tripping, load rejection, and bus-tie switching countermeasures. The proposed SIPS can prevent isolated power system blackout from extreme contingencies system and provide a valuable system simulation experience for similar independent power grids.

  7. Power outages, power externalities, and baby booms.

    Science.gov (United States)

    Burlando, Alfredo

    2014-08-01

    Determining whether power outages have significant fertility effects is an important policy question in developing countries, where blackouts are common and modern forms of family planning are scarce. Using birth records from Zanzibar, this study shows that a month-long blackout in 2008 caused a significant increase in the number of births 8 to 10 months later. The increase was similar across villages that had electricity, regardless of the level of electrification; villages with no electricity connections saw no changes in birth numbers. The large fertility increase in communities with very low levels of electricity suggests that the outage affected the fertility of households not connected to the grid through some spillover effect. Whether the baby boom is likely to translate to a permanent increase in the population remains unclear, but this article highlights an important hidden consequence of power instability in developing countries. It also suggests that electricity imposes significant externality effects on rural populations that have little exposure to it.

  8. Curing critical links in oscillator networks as power grid models

    CERN Document Server

    Rohden, Martin; Timme, Marc; Meyer-Ortmanns, Hildegard

    2015-01-01

    Modern societies crucially depend on the robust supply with electric energy. Blackouts of power grids can thus have far reaching consequences. During a blackout, often the failure of a single infrastructure, such as a critical transmission line, results in several subsequent failures that spread across large parts of the network. Preventing such large-scale outages is thus key for assuring a reliable power supply. Here we present a non-local curing strategy for oscillatory power grid networks based on the global collective redistribution of loads. We first identify critical links and compute residual capacities on alternative paths on the remaining network from the original flows. For each critical link, we upgrade lines that constitute bottlenecks on such paths. We demonstrate the viability of this strategy for random ensembles of network topologies as well as topologies derived from real transmission grids and compare the nonlocal strategy against local back-ups of critical links. These strategies are indep...

  9. Hybrid Model for Cascading Outage in a Power System: A Numerical Study

    Science.gov (United States)

    Susuki, Yoshihiko; Takatsuji, Yu; Hikihara, Takashi

    Analysis of cascading outages in power systems is important for understanding why large blackouts emerge and how to prevent them. Cascading outages are complex dynamics of power systems, and one cause of them is the interaction between swing dynamics of synchronous machines and protection operation of relays and circuit breakers. This paper uses hybrid dynamical systems as a mathematical model for cascading outages caused by the interaction. Hybrid dynamical systems can combine families of flows describing swing dynamics with switching rules that are based on protection operation. This paper refers to data on a cascading outage in the September 2003 blackout in Italy and shows a hybrid dynamical system by which propagation of outages reproduced is consistent with the data. This result suggests that hybrid dynamical systems can provide an effective model for the analysis of cascading outages in power systems.

  10. Understanding the cascading failures in Indian power grids with complex networks theory

    Science.gov (United States)

    Zhang, Guidong; Li, Zhong; Zhang, Bo; Halang, Wolfgang A.

    2013-08-01

    Two huge blackouts, occurred separately on 30 and 31 July 2012 in India, spread over half the country when three of its five regional grids collapsed, leaving hundreds of millions of people without government-supplied electricity and ringing once again alarm bells with security problems in electric power grid systems. The first investigation reveals that the outage of the second (backup) 400 kV Bina-Gwalior-Agra line on 29 July 2012 led to the cascading failure through the grid, which can be simulated and explained from the perspective of the complex networks theory. In this paper, a new model of a power grid involving the active and reactive power loads is proposed and then used to analyze the cascading behavior of power grids, which is also used to explain the reason of the blackout happening in India. Furthermore, some strategic advices are given for improving the stability and security of power grids, especially Indian power grids.

  11. Development of stabilizing control systems for preventing expansion of loss of synchronism; Denryoku keito anteika system no gijutsu doko

    Energy Technology Data Exchange (ETDEWEB)

    Sato, M.; Hirokawa, T.; Tsukui, R. [Toshiba Corp., Tokyo (Japan)

    1995-11-01

    The size and complexity of electric power systems has been increasing as a result of the construction of new generators, subsections, and lines to meet the steady growth in load demand. Electricity is an essential form of energy that supports society, and utilities are required to ensure high-quality electricity supplies without interruption. However, faults such as lightning may cause loss of synchronism among generators, leading to a blackout. In order to prevent such an expansion of loss of synchronism, many systems based on the latest technologies have been developed and applied. This paper outlines various types of disturbances that occur in electric power systems, and describes approaches and systems for preventing blackouts. In addition, a description is given of new functions that will be required in the near future in order to maintain the stability of electric power networks. 1 fig., 4 tabs.

  12. Power Transmission System Vulnerability Assessment Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    E. Karimi

    2012-11-01

    Full Text Available Recent blackouts in power systems have shown the necessity of vulnerability assessment. Among all factors, transmission system components have a more important role. Power system vulnerability assessment could capture cascading outages which result in large blackouts and is an effective tool for power system engineers for defining power system bottlenecks and weak points. In this paper a new method based on fault chains concept is developed which uses new measures. Genetic algorithm with an effective structure is used for finding vulnerable branches in a practical power transmission system. Analytic hierarchy process is a technique used to determine the weighting factors in fitness function of genetic algorithm. Finally, the numerical results for Isfahan Regional Electric Company are presented which verifies the effectiveness and precision of the proposed method according to the practical expriments.

  13. A matching approach to communicate through the plasma sheath surrounding a hypersonic vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Xiaotian; Jiang, Binhao, E-mail: jiangbh@hit.edu.cn [Harbin Institute of Technology, 92 West Dazhi Street, Nan Gang District, Harbin (China)

    2015-06-21

    In order to overcome the communication blackout problem suffered by hypersonic vehicles, a matching approach has been proposed for the first time in this paper. It utilizes a double-positive (DPS) material layer surrounding a hypersonic vehicle antenna to match with the plasma sheath enclosing the vehicle. Analytical analysis and numerical results indicate a resonance between the matched layer and the plasma sheath will be formed to mitigate the blackout problem in some conditions. The calculated results present a perfect radiated performance of the antenna, when the match is exactly built between these two layers. The effects of the parameters of the plasma sheath have been researched by numerical methods. Based on these results, the proposed approach is easier to realize and more flexible to the varying radiated conditions in hypersonic flight comparing with other methods.

  14. MELCOR DB Construction for the Severe Accident Analysis DB

    Energy Technology Data Exchange (ETDEWEB)

    Song, Y. M.; Ahn, K. I. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    The Korea Atomic Energy Research Institute (KAERI) has been constructing a severe accident analysis database (DB) under a National Nuclear R and D Program. In particular, an MAAP (commercial code being widely used in industries for integrated severe accident analysis) DB for many scenarios including a station blackout (SBO) has been completed. This paper shows the MELCOR DB construction process with examples of SBO scenarios, and the results will be used for a comparison with the MAAP DB

  15. Differential evolutionary algorithm for distribution capacitor allocation considering varying load conditions

    OpenAIRE

    Karimi, Mohammad

    2011-01-01

    Many loads in power systems are inductive loads then consume reactive power, this fact lead to drop voltage and in worst case blackout and collapse voltage. Best option in distribution networks for avoid of this problem is installation of capacitor bank. In capacitor installation, finding optimal location and size of capacitor have special importance. In this paper, Differential Evolutionary (DE) algorithm is proposed for optimal placement and sizing of capacitor. Our objective funct...

  16. Understanding Social Media and Mass Mobilization in the Operational Environment

    Science.gov (United States)

    2015-05-21

    numbers of disaffected youth armed with smart phones and extended social media networks .39 US decision- makers may ask the US military to respond to... network experiences an overall failure that may not be recoverable. An example used by the Santa Fe Institute is the electrical blackout in 2003 in...understand potential threats using characteristics of self-organization, anticipate using emergent properties, and exploit the properties of networks inherent

  17. A Comparison of High-Latitude Ionosphere Propagation Predictions from AMBCOM with Measured Data

    Science.gov (United States)

    1991-03-01

    radar . The point-to-point mode performs raytracing from a transmitter to a receiver and was used for this thesis. RIAYTRA co,-,putes grokil times... RADAR C and AMBCOM....... 9 3. Thc Naval Postgraduate School Studies ......................... 9 II. THE AMBIENT COMMUNICATIONS MO0DEL (AMBCOM...the transpolar path such as the a communications blackout on 12 November 1986. [Ref. 11] 2. Hi2h-Latitude HF Predictions From RADAR C and AMBCOM

  18. Operator’s Manual for UH-60A Helicopter, UH-60L Helicopter, EH-60A Helicopter

    Science.gov (United States)

    2007-11-02

    chief seating, troop seating, litter installation and cargo. Restraint of cargo is by tiedown rings installed in the floor. Two stowage compartments, at... rack mounts and seats. Blackout curtains may be used to eliminate any light intrusion into the cockpit during night operations, or any glare on the...24 CH EC K L IST ST OW AG E DA TA & MA P CHECK LIST DATA & MAP STOWAGE 1. UPPER CONSOLE 2. PILOT’S COCKPIT UTILITY LIGHT 3. FREE−AIR TEMPERATURE

  19. Continuation Power Flow Method based Assessment of Static Voltage Stability considering the Power System Contingencies

    OpenAIRE

    Khan Aafreen; Tiwari Prasad Shankarshan

    2014-01-01

    Power system security is recognized as one of the major problems in many power systems throughout the world. Power system insecurity such as transmission lines being overloaded causes transmission elements cascade outages, which may lead to complete blackout. In accordance with these reasons, the prediction and recognition of voltage instability in power system has particular importance and it makes the network security stronger. This work, by considering the power system continge...

  20. Wide Area Measurement Applications for Improvement of Power System Protection

    OpenAIRE

    Tania, Mutmainna

    2013-01-01

    The increasing demand for electricity over the last few decades has not been followed by adequate growth in electric infrastructure. As a result, the reliability and safety of the electric grids are facing tremendously growing pressure. Large blackouts in the recent past indicate that sustaining system reliability and integrity turns out to be more and more difficult due to reduced transmission capacity margins and increased stress on the system. Due to the heavy loading conditions that occur...

  1. Hybrid Model for Cascading Outage in a Power System: A Numerical Study

    OpenAIRE

    Susuki, Yoshihiko; Takatsuji, Yu; Hikihara, Takashi

    2009-01-01

    Analysis of cascading outages in power systems is important for understanding why large blackouts emerge and how to prevent them. Cascading outages are complex dynamics of power systems, and one cause of them is the interaction between swing dynamics of synchronous machines and protection operation of relays and circuit breakers. This paper uses hybrid dynamical systems as a mathematical model for cascading outages caused by the interaction. Hybrid dynamical systems can combine families of fl...

  2. Lassoing Line Outages in the Smart Power Grid

    OpenAIRE

    Zhu, Hao; Giannakis, Georgios B.

    2011-01-01

    Fast and accurate unveiling of power line outages is of paramount importance not only for preventing faults that may lead to blackouts, but also for routine monitoring and control tasks of the smart grid, including state estimation and optimal power flow. Existing approaches are either challenged by the \\emph{combinatorial complexity} issues involved, and are thus limited to identifying single- and double-line outages; or, they invoke less pragmatic assumptions such as \\emph{conditionally ind...

  3. Adolescent Alcohol Exposure Persistently Impacts Adult Neurobiology and Behavior

    OpenAIRE

    Crews, Fulton T.; Vetreno, Ryan P.; Broadwater, Margaret A.; Robinson, Donita L.

    2016-01-01

    Adolescence is a developmental period when physical and cognitive abilities are optimized, when social skills are consolidated, and when sexuality, adolescent behaviors, and frontal cortical functions mature to adult levels. Adolescents also have unique responses to alcohol compared with adults, being less sensitive to ethanol sedative–motor responses that most likely contribute to binge drinking and blackouts. Population studies find that an early age of drinking onset correlates with increa...

  4. More regulation is necessary; Mere regulering er noedvendig

    Energy Technology Data Exchange (ETDEWEB)

    Trong, Maj Dang

    2004-07-01

    The EU Commission has submitted a proposal to increase the power supply security in the member countries. This proposal includes a package of initiatives intended to speed up investment in the power transmission connections between the EU countries. But increased transmission capacity alone cannot guarantee the supply and prevent serious blackouts like those occurring in 2003. The Commission also presents a controversial proposal to instruct the member countries to reduce energy consumption by 1 per cent per year.

  5. Reducing the Vulnerability of Electric Power Grids to Terrorist Attacks

    Energy Technology Data Exchange (ETDEWEB)

    Ross Baldick; Thekla Boutsika; Jin Hur; Manho Joung; Yin Wu; Minqi Zhong

    2009-01-31

    This report describes the development of a cascading outage analyzer that, given an initial disturbance on an electric power system, checks for thermal overloads, under-frequency and over-frequency conditions, and under-voltage conditions that would result in removal of elements from the system. The analyzer simulates the successive tripping of elements due to protective actions until a post-event steady state or a system blackout is reached.

  6. Power Outage - 16 October

    CERN Multimedia

    2014-01-01

    At 19:03 last night, a fire in an 18kV circuit breaker in building 212 led to a blackout on the Meyrin site. The CERN fire brigade rapidly brought the fire under control and power was restored by 22:25. Many CERN systems were affected and have been brought back in to service overnight, this work will continue through the day.

  7. Demand Response Spinning Reserve Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Eto, Joseph H.; Nelson-Hoffman, Janine; Torres, Carlos; Hirth,Scott; Yinger, Bob; Kueck, John; Kirby, Brendan; Bernier, Clark; Wright,Roger; Barat, A.; Watson, David S.

    2007-05-01

    The Demand Response Spinning Reserve project is a pioneeringdemonstration of how existing utility load-management assets can providean important electricity system reliability resource known as spinningreserve. Using aggregated demand-side resources to provide spinningreserve will give grid operators at the California Independent SystemOperator (CAISO) and Southern California Edison (SCE) a powerful, newtool to improve system reliability, prevent rolling blackouts, and lowersystem operating costs.

  8. Radiation Characteristics of Antennas Embedded in a Layer with Two-Temperature Electron Population

    Science.gov (United States)

    2013-10-01

    concepts are questionable under non -ideal conditions encountered in practice. Hence the issue of communication blackout is as ``topical" as it was...assumption that the electrons have Maxwellian distribution. Furthermore, there are other ways (see for example, [37], [38]), besides that using a...velocity of the EAW will be accelerated by the EAW. As commonly done, particle velocities are modeled as a Maxwellian distribution function. Thus there

  9. Solar storms; Tormentas solares

    Energy Technology Data Exchange (ETDEWEB)

    Collaboration: Pereira Cuesta, S.; Pereira Pagan, B.

    2016-08-01

    Solar storms begin with an explosion, or solar flare, on the surface of the sun. The X-rays and extreme ultraviolet radiation from the flare reach the Earths orbit minutes later-travelling at light speed. The ionization of upper layers of our atmosphere could cause radio blackouts and satellite navigation errors (GPS). Soon after, a wave of energetic particles, electrons and protons accelerated by the explosion crosses the orbit of the Earth, and can cause real and significant damage. (Author)

  10. Digitalized distribution system for the power supply. Internet of the energy; Digitalisiertes Verteilungsnetz fuer die Stromversorgung. Internet der Energie

    Energy Technology Data Exchange (ETDEWEB)

    Reifenhaeuser, Bernd; Ebbes, Alexander [GIP AG, Mainz (Germany)

    2013-05-13

    Current power distribution systems are highly connected with each other, redundantly designed with respect to the security of supply and require a central planning. Due to the close interlocking, disturbances may spread quickly and lead to a large-scale blackout. In order to counteract failures in the face of an increasing share of renewable energy, energy has to be hold out - an inefficient and expensive reserve. A decentralized, digital power distribution system may handle the task much better.

  11. Contribution of Water Saving to a Stable Power Supply in Vietnam

    Directory of Open Access Journals (Sweden)

    Takayuki Otani

    2015-06-01

    Full Text Available In Vietnam, the rapid expansion of cities is exceeding the supply capacity for water and electricity, and restrictions on water supply and blackouts occur on a daily basis. In this study, the authors examined whether water-saving equipment could solve these problems. This paper focused on toilet bowls that consumed a large amount of water, and on showers for which heat consumption was high. In Vietnam, the main heat source for showers is the electric water heater, typically having a power consumption of 2500–4500 W. Although the current diffusion rate of such water heaters is just 13%, their use will spread widely in the future. These heaters have already placed a peak load on electricity consumption in winter when a large amount of energy is consumed for heating water, and they will become a significant factor in blackout risks as their use becomes commonplace nationwide. It is clear that the introduction of water-saving showers will allow not only a more efficient use of water resources, but will also mitigate against the risk of blackouts.

  12. A FMM-FFT accelerated hybrid volume surface integral equation solver for electromagnetic analysis of re-entry space vehicles

    KAUST Repository

    Yücel, Abdulkadir C.

    2014-07-01

    Space vehicles that re-enter the atmosphere often experience communication blackout. The blackout occurs when the vehicle becomes engulfed in plasma produced by interactions between the vehicle surface and the atmosphere. The plasma often is concentrated in a relatively thin shell around the vehicle, with higher densities near its nose than rear. A less structured, sometimes turbulent plasma wake often trails the vehicle. The plasma shell severely affects the performance of side-mounted antennas as it alters their characteristics (frequency response, gain patterns, axial ratio, and impedance) away from nominal, free-space values, sometimes entirely shielding the antenna from the outside world. The plasma plume/turbulent wake similarly affect the performance of antennas mounted at the back of the vehicle. The electromagnetic characteristics of the thin plasma shell and plume/turbulent wake heavily depend on the type of re-entry trajectory, the vehicle\\'s speed, angles of attack, and chemical composition, as well as environmental conditions. To analyze the antennas\\' performance during blackout and to design robust communication antennas, efficient and accurate simulation tools for charactering the antennas\\' performance along the trajectory are called for.

  13. Application of Advanced Wide Area Early Warning Systems with Adaptive Protection

    Energy Technology Data Exchange (ETDEWEB)

    Blumstein, Carl [Univ. of California, Berkeley, CA (United States); Cibulka, Lloyd [Univ. of California, Berkeley, CA (United States); Thorp, James [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Centeno, Virgilio [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); King, Roger [Mississippi State Univ., Mississippi State, MS (United States); Reeves, Kari [Mississippi State Univ., Mississippi State, MS (United States); Ashrafi, Frank [Southern California Edison Co., Rosemead, CA (United States); Madani, Vahid [Pacific Gas & Electric Co., San Francisco, CA (United States)

    2014-09-30

    Recent blackouts of power systems in North America and throughout the world have shown how critical a reliable power system is to modern societies, and the enormous economic and societal damage a blackout can cause. It has been noted that unanticipated operation of protection systems can contribute to cascading phenomena and, ultimately, blackouts. This project developed and field-tested two methods of Adaptive Protection systems utilizing synchrophasor data. One method detects conditions of system stress that can lead to unintended relay operation, and initiates a supervisory signal to modify relay response in real time to avoid false trips. The second method detects the possibility of false trips of impedance relays as stable system swings “encroach” on the relays’ impedance zones, and produces an early warning so that relay engineers can re-evaluate relay settings. In addition, real-time synchrophasor data produced by this project was used to develop advanced visualization techniques for display of synchrophasor data to utility operators and engineers.

  14. Improving the Transmission System Reliability for the 154kV Radial Network Operation

    Energy Technology Data Exchange (ETDEWEB)

    Choo, Jin Boo; Yoo, Myeong Ho; Yoon, Young Beum; Kim, Tae Won [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Lee, Gi Won; Chung, Beom Jin; Jung, Jung Won; Park, Kyu Hyun; Lee, Myung Hee; Kim, Hyun Jong; Kim, Chae Hee [KEYIN CO., (Korea, Republic of)

    1996-12-31

    Analyzing that 154kV radial network current ed operated, we developed Automatic Power Reconfiguration System(APRS) which restore blackout area. It consists of special data acquisition system(DAU) and central monitoring system for reason of protecting currently operating power system. In addition, it communicates using optical communication network for high speed data transmission and accuracy. An Accuracy of operation and stability of the developed system is tested using Real Time Digital Simulator in 3-bus equivalent model system. In An Outage case, our developed system can restore a blackout area in three second. An ability of the restoration of a blackout was verified by simulations. For the field test, the developed system was set up at SINCHON S/S, SESOMUN S/S, SINDANG S/S and MAJANG S/S governed by Seoul Power Transmission Center. If the system reliability is proved for a one year test in real power system, application of the system will be extended to the other substations.

  15. 基于层次分析法和熵权法的电网风险评估%Risk Assessment of Power Networks Based on AHP and Entropy Weight Method

    Institute of Scientific and Technical Information of China (English)

    刘宇彬; 刘建华

    2013-01-01

    Some indicators of large-scale electric power networks have significant impact on the large-scale black-outs and chain collapse of a power system. In order to find the lines that will have a huge impact on the whole net-work after a fault switching-off, and prevent large-scale blackouts, this paper proposes and establishes an objective and rational safety evaluation system for distribution networks, in which the analytic hierarchy process ( AHP) and entropy weight method are used to conduct an objectively and subjectively risk assessment of a distribution network, quantify vulnerable lines from a quantitative point of view, and provide information for decision making to prevent cascading trips and large-scale blackouts. The proposed method is verified in IEEE39 node system.%大规模电力网络中,某些指标对电力系统大规模停电和连锁崩溃的发生有着重要的影响。为了寻找因故障开断后将会对全网造成巨大影响的线路,从而达到预防大规模停电的效果,建立了一套客观合理的配电网安全性评估体系,并运用层次分析法和熵权法相综合的主客观并重的评价方法对配电网进行风险评估,从定量的角度量化出较为脆弱的线路,为预防连锁跳闸和大规模停电提供决策信息。在IEEE39节点系统上对此方法予以验证。

  16. Severe accident analysis of a small LOCA accident using MAAP-CANDU support level 2 PSA for the Point Lepreau station refurbishment project

    Energy Technology Data Exchange (ETDEWEB)

    Petoukhov, S.M.; Brown, M.J.; Mathew, P.M. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2012-07-01

    A Level 2 Probabilistic Safety Assessment was performed for the Point Lepreau Generating Station. The MAAP4-CANDU code was used to calculate the progression of postulated severe core damage accidents and fission product releases. Five representative severe core damage accidents were selected: Station Blackout, Small Loss-of-Coolant Accident, Stagnation Feeder Break, Steam Generator Tube Rupture, and Shutdown State Accident. Analysis results for only the reference Small LOCA Accident scenario (which is a very low probability event) are discussed in this paper. (author)

  17. Chokepoints global private regulation on the Internet

    CERN Document Server

    Tusikov, Natasha

    2016-01-01

    In January 2012, millions participated in the now-infamous "Internet blackout" against the Stop Online Piracy Act, protesting the power it would have given intellectual property holders over the Internet. However, while SOPA's withdrawal was heralded as a victory for an open Internet, a small group of corporations, tacitly backed by the US and other governments, have implemented much of SOPA via a series of secret, handshake agreements. Drawing on extensive interviews, Natasha Tusikov details the emergence of a global regime in which large Internet firms act as regulators for powerful intellec

  18. Early results of microwave transmission experiments through an overly dense rectangular plasma sheet with microparticle injection

    Science.gov (United States)

    Gillman, Eric D.; Amatucci, W. E.

    2014-06-01

    These experiments utilize a linear hollow cathode to create a dense, rectangular plasma sheet to simulate the plasma layer surrounding vehicles traveling at hypersonic velocities within the Earth's atmosphere. Injection of fine dielectric microparticles significantly reduces the electron density and therefore lowers the electron plasma frequency by binding a significant portion of the bulk free electrons to the relatively massive microparticles. Measurements show that microwave transmission through this previously overly dense, impenetrable plasma layer increases with the injection of alumina microparticles approximately 60 μm in diameter. This method of electron depletion is a potential means of mitigating the radio communications blackout experienced by hypersonic vehicles.

  19. Development of a Sequential Restoration Strategy Based on the Enhanced Dijkstra Algorithm for Korean Power Systems

    OpenAIRE

    Bokyung Goo; Solyoung Jung; Jin Hur

    2016-01-01

    When a blackout occurs, it is important to reduce the time for power system restoration to minimize damage. For fast restoration, it is important to reduce taking time for the selection of generators, transmission lines and transformers. In addition, it is essential that a determination of a generator start-up sequence (GSS) be made to restore the power system. In this paper, we propose the optimal selection of black start units through the generator start-up sequence (GSS) to minimize the re...

  20. 区域互联电网故障解列方法综述%Comments and Overviews on the Islanding Methods of Large Interconnected Power Grid

    Institute of Scientific and Technical Information of China (English)

    胥威汀; 戴松灵; 张全明; 杜新伟; 任志超

    2015-01-01

    Grid islanding is the last defense of the security and stability of power grid. It can inhibit the spreading of serious disturbance in power system, such as oscillatory and instability between asynchronous generator groups, and create self-balancing environment for every isolated island. The successful grid islanding control can save many power loads, and avoid large-scale blackout, such as the blackout of USA and Canada in 2003, the Brazil blackout in 2009 and the India blackout in 2012. So the grid islanding control would contribute to reduce the losses of national economy, and maintain the social stability and safety. On the contrary, an unsuccessful grid islanding control would suffer the power system and the society. In the paper, the development of the grid islanding control had been overviewed from the aspects of engineering application and theoretical research. The theoretical research of grid islanding control and its problems were summarized, including the splitting surface definition methods and splitting timing judgment methods. Suggestions for these issues were proposed in the paper.%解列控制是电力系统安全稳定控制的最后一道防线,其作用在于阻断严重扰动在电网中的恶性蔓延,如异步机群振荡失稳,并为解开后的孤网创造一个自平衡的运行环境.成功的解列能够挽救大量的电力负荷,避免发生如2003年美加大停电、2009年巴西大停电和2012年印度大停电等类似的大范围事故,减轻国民经济损失,维持社会稳定安全;而不成功的解列则会导致系统遭受更大的冲击.该文从工程应用和理论研究两个层面对电网解列现状进行了综述,总结出当前解列控制及其理论研究中尚存的问题,包括解列面界定方法、解列时机判断等问题,并针对这些问题提出相应建议.

  1. The natural gas for electric energy production and other industrial inputs by using cogeneration; O gas natural na producao de energia eletrica e outros insumos industriais atraves da cogeracao

    Energy Technology Data Exchange (ETDEWEB)

    Mariotoni, Carlos Alberto [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil]. E-mail: cam@fec.unicamp.br

    2002-07-01

    This paper discusses the benefits of using natural gas in the cogeneration plants for electric power generation, and others inputs used in the different industrial sectors. Afterwards the end of the state monopoly on electrical energy generation, the cogeneration systems have been stimulated. The construction of the Brazil-Bolivia gas pipeline gives the real possibility of utilization of natural gas as an effective energy alternative what can help to minimize the industrial energy blackout, mainly in the pipeline neighbourhood. This work also presents both the economic and technical advantages of using natural gas at existing industrial plants in the region of Jundiai city at the State of Sao Paulo. (author)

  2. Wind Power Impact to Transient and Voltage Stability of the Power System in Eastern Denmark

    DEFF Research Database (Denmark)

    Rasmussen, Joana; Jørgensen, Preben; Palsson, Magni Thor

    2005-01-01

    Voltage stability, transient stability and reactive power compensation are extremely important issues for largescale integration of wind power in areas distant from the main transmission system in Eastern Denmark. This paper describes the application of a dynamic wind farm model in simulation...... studies for assessments of a large wind power penetration. The simulation results reveal problems with voltage stability due to the characteristic of wind turbine generation as well as the inability of the power system to meet the reactive power demand. Furthermore, the established model is applied...... to analyse challenges in system protection as means to reduce the risk of widespread blackouts....

  3. Multiagent System-Based Wide-Area Protection and Control Scheme against Cascading Events

    DEFF Research Database (Denmark)

    Liu, Zhou; Chen, Zhe; Sun, Haishun

    2015-01-01

    In this paper, a multi agent system (MAS) based wide area protection and control scheme is proposed to deal with the long term voltage instability induced cascading trips. Based on sensitivity analysis between the relay operation margin and power system state variables, an optimal emergency contr...... strategy. A hybrid simulation platform based on LabVIEW and real time digital simulator (RTDS) is set up to simulate a blackout case in the power system of Eastern Denmark and to demonstrate the effectiveness of the proposed MAS based protection strategy....

  4. Multi-Agent System Based Special Protection and Emergency Control Scheme against Cascading Events in Power System

    DEFF Research Database (Denmark)

    Liu, Zhou

    the proposed protection strategy in this thesis, a real time simulation platform based on Real Time Digital Simulator (RTDS) and LabVIEW is built. In this platform, the cases of cascaded blackouts are simulated on the test system simplified from the East Denmark power system. For the MAS based control system......, the distributed power system agents are set up in RTDS, while the agents in higher level are designed by LabVIEW toolkits. The case studies and simulation results demonstrate the effectiveness of real time application of the proposed MAS based special protection and emergency control scheme against the cascaded...

  5. One year of Italian press review in the energy domain; Une annee de revue de presse italienne dans le domaine de l'energie

    Energy Technology Data Exchange (ETDEWEB)

    Augier, L.; Perna, N.; Carles, R.

    2004-03-01

    In terms of energy, 2003 has been an important and key year for Italy with a highlight: the black-out of September 28, 2003 which has paralyzed part of Italy. This event has led to think about the necessity for Italy to diversify its energy sources. This requires a reinforcement of energy efficiency, a rational use of energy, a policy of construction of new facilities, the use of biomass fuels and the promotion of renewable energy sources. This report groups together the overall brief news written by the scientific service of the French Embassy in Italy about this topic and spread to the readers of electronic bulletins. (J.S.)

  6. Review of Network Topologies and Protection Principles in Marine and Offshore Applications

    DEFF Research Database (Denmark)

    Ciontea, Catalin-Iosif; Bak, Claus Leth; Blaabjerg, Frede;

    2015-01-01

    , collision with the cliff, reef or other ships and electrical shocks to humans. In order to cope with the unwanted effects of a fault, several protection strategies are applied, but complexity of the marine and offshore applications is continuously increasing, so protection needs to overcome more and more......An electric fault that is not cleared is harmful in land applications, but in marine and offshore sector it can have catastrophic consequences. If the protection system fails to operate properly, the following situation may occur: blackouts, fire, loss of propulsion, delays in transportation...

  7. Combating False Reports for Secure Networked Control in Smart Grid via Trustiness Evaluation

    CERN Document Server

    Li, Husheng; Djouadi, Seddik M

    2010-01-01

    Smart grid, equipped with modern communication infrastructures, is subject to possible cyber attacks. Particularly, false report attacks which replace the sensor reports with fraud ones may cause the instability of the whole power grid or even result in a large area blackout. In this paper, a trustiness system is introduced to the controller, who computes the trustiness of different sensors by comparing its prediction, obtained from Kalman filtering, on the system state with the reports from sensor. The trustiness mechanism is discussed and analyzed for the Linear Quadratic Regulation (LQR) controller. Numerical simulations show that the trustiness system can effectively combat the cyber attacks to smart grid.

  8. The X-33 Extended Flight Test Range

    Science.gov (United States)

    Mackall, Dale A.; Sakahara, Robert; Kremer, Steven E.

    1998-01-01

    Development of an extended test range, with range instrumentation providing continuous vehicle communications, is required to flight-test the X-33, a scaled version of a reusable launch vehicle. The extended test range provides vehicle communications coverage from California to landing at Montana or Utah. This paper provides an overview of the approaches used to meet X-33 program requirements, including using multiple ground stations, and methods to reduce problems caused by reentry plasma radio frequency blackout. The advances used to develop the extended test range show other hypersonic and access-to-space programs can benefit from the development of the extended test range.

  9. A study of core melting phenomena in reactor severe accident of PWR

    Energy Technology Data Exchange (ETDEWEB)

    Jeun, Gyoo Dong; Park, Shane; Kim, Jong Sun; Kim, Sung Joong [Hanyang Univ., Seoul (Korea, Republic of); Kim, Jin Man [Korea Maritime Univ., Busan (Korea, Republic of)

    2001-03-15

    In the 4th year, SCDAP/RELAP5 best estimate input data obtained from the TMI-2 accident analysis were applied to the analysis of domestic nuclear power plant. Ulchin nuclear power plant unit 3, 4 were selected as reference plant and steam generator tube rupture, station blackout SCDAP/RELAP5 calculation were performed to verify the adequacy of the best estimate input parameters and the adequacy of related models. Also, System 80+ EVSE simulation was executed to study steam explosion phenomena in the reactor cavity and EVSE load test was performed on the simplified reactor cavity geometry using TRACER-II code.

  10. The scenario-based approach adopted in the ELECTRA project for deriving innovate control room functionality

    DEFF Research Database (Denmark)

    Marinelli, Mattia; Heussen, Kai; Prostejovsky, Alexander

    2017-01-01

    . The paper intends to outline the methodology adopted, which is based on the cognitive work analysis framework, to provide an overview of the most interesting scenarios and to summarize the requirements analysis results. In order to derive required control room functionality, a set of relevant control room...... scenarios have been identified based on the Web-of-Cells control concept. We considered scenarios that challenge traditional control schemes, scenarios that caused major failures (i.e., blackouts) and scenarios that can be expected to appear in the future. For each scenario, information concerning network...

  11. Fusion

    CERN Document Server

    Mahaffey, James A

    2012-01-01

    As energy problems of the world grow, work toward fusion power continues at a greater pace than ever before. The topic of fusion is one that is often met with the most recognition and interest in the nuclear power arena. Written in clear and jargon-free prose, Fusion explores the big bang of creation to the blackout death of worn-out stars. A brief history of fusion research, beginning with the first tentative theories in the early 20th century, is also discussed, as well as the race for fusion power. This brand-new, full-color resource examines the various programs currently being funded or p

  12. Battery Electric Vehicles can reduce greenhouse has emissions and make renewable energy cheaper in India

    Energy Technology Data Exchange (ETDEWEB)

    Gopal, Anand R [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Witt, Maggie [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sheppard, Colin [Humboldt State Univ., Arcata, CA (United States); Harris, Andrew [Humboldt State Univ., Arcata, CA (United States)

    2015-07-01

    India's National Mission on Electric Mobility (NMEM) sets a countrywide goal of deploying 6 to 7 million hybrid and electric vehicles (EVs) by 2020. There are widespread concerns, both within and outside the government, that the Indian grid is not equipped to accommodate additional power demand from battery electric vehicles (BEVs). Such concerns are justified on the grounds of India's notorious power sector problems pertaining to grid instability and chronic blackouts. Studies have claimed that deploying BEVs in India will only

  13. CFD Analysis of the Anti-Surge Effects by Water Hammering

    Science.gov (United States)

    Kim, Tae-oh; Jeong, Hyo-min; Chung, Han-shik; Lee, Sin-il; Lee, Kwang-sung

    2015-09-01

    Water hammering occurs due to the surge effect that comes from operating the pump, sudden stop during the operating due to a blackout and rapid open and close of the valve. By the water hammering of the pipeline and the pump, the valve are damaged. In this paper, transient analysis is conducted by CFD (Computational Fluid Dynamics). The purpose of this paper is to provide the research data about the change of the pressure and flow in the pipe that caused by the water hammering.

  14. Interactive transport of multi-view videos for 3DTV applications

    Institute of Scientific and Technical Information of China (English)

    KURUTEPE Engin; CIVANLAR M. Reha; TEKALP A. Murat

    2006-01-01

    The authors propose a novel method for transporting multi-view videos that aims to keep the bandwidth requirements on both end-users and servers as low as possible. The method is based on application layer multicast, where each end point receives only a selected number of views required for rendering video from its current viewpoint at any given time. The set of selected videos changes in real time as the user's viewpoint changes because of head or eye movements. Techniques for reducing the black-outs during fast viewpoint changes were investigated. The performance of the approach was studied through network experiments.

  15. Control and Protection Cooperation Strategy for Voltage Instability

    DEFF Research Database (Denmark)

    Liu, Zhou; Chen, Zhe; Sun, Haishun;

    2012-01-01

    Most cascaded blackouts are caused by unexpected backup relay operations due to low voltage or overload state caused by post fault load restoration dynamics. If such state can be sensed and adjusted appropriately prior to those relay actions, system stability might be sustained. This paper proposed...... a control and protection cooperation strategy to prevent post fault voltage instability. The multi-agent technology is applied for the strategy implementation; the criteria based on wide area measured apparent impedances are defined to choose the control strategy, such as tap changer adjusting or load...

  16. FAULT RESTORATION OF DISTRIBUTION NETWORK BASED ON GENETIC ALGORITHM%基于遗传算法的地区电网停电恢复

    Institute of Scientific and Technical Information of China (English)

    盛四清; 梁志瑞; 张文勤; 杨以涵

    2001-01-01

    Genetic algorithm (GA) is applied to the fault restoration in distribution network in this paper. The network reconfiguration of a blackout area is carried out with GA, which means that each blackout area is divided into several sub-areas provided electricity through different power sources. As a result, the restoration scheme is formed ultimately. Through tested on practical power network, not only can optimal solution be obtained, but also several sub-optimal solutions, which can provide operators with more reference information.%提出将遗传算法应用于地区电网停电恢复,由遗传算法对停电区域进行网络重构,将其划分成若干个子区域,分别由不同的供电路径供电,由此形成恢复方案。通过对实际电网的测试分析表明,将遗传算法应用于地区电网停电恢复,不仅能得到最优解,而且能得到若干次优解,可为运行人员提供更多的参考信息。

  17. Nuclear Power Plant

    Directory of Open Access Journals (Sweden)

    Analia Bonelli

    2012-01-01

    Full Text Available A description of the results for a Station Black-Out analysis for Atucha 2 Nuclear Power Plant is presented here. Calculations were performed with MELCOR 1.8.6 YV3165 Code. Atucha 2 is a pressurized heavy water reactor, cooled and moderated with heavy water, by two separate systems, presently under final construction in Argentina. The initiating event is loss of power, accompanied by the failure of four out of four diesel generators. All remaining plant safety systems are supposed to be available. It is assumed that during the Station Black-Out sequence the first pressurizer safety valve fails stuck open after 3 cycles of water release, respectively, 17 cycles in total. During the transient, the water in the fuel channels evaporates first while the moderator tank is still partially full. The moderator tank inventory acts as a temporary heat sink for the decay heat, which is evacuated through conduction and radiation heat transfer, delaying core degradation. This feature, together with the large volume of the steel filler pieces in the lower plenum and a high primary system volume to thermal power ratio, derives in a very slow transient in which RPV failure time is four to five times larger than that of other German PWRs.

  18. Contingency Analysis of Cascading Line Outage Events

    Energy Technology Data Exchange (ETDEWEB)

    Thomas L Baldwin; Magdy S Tawfik; Miles McQueen

    2011-03-01

    As the US power systems continue to increase in size and complexity, including the growth of smart grids, larger blackouts due to cascading outages become more likely. Grid congestion is often associated with a cascading collapse leading to a major blackout. Such a collapse is characterized by a self-sustaining sequence of line outages followed by a topology breakup of the network. This paper addresses the implementation and testing of a process for N-k contingency analysis and sequential cascading outage simulation in order to identify potential cascading modes. A modeling approach described in this paper offers a unique capability to identify initiating events that may lead to cascading outages. It predicts the development of cascading events by identifying and visualizing potential cascading tiers. The proposed approach was implemented using a 328-bus simplified SERC power system network. The results of the study indicate that initiating events and possible cascading chains may be identified, ranked and visualized. This approach may be used to improve the reliability of a transmission grid and reduce its vulnerability to cascading outages.

  19. A study of cascading failures in real and synthetic power grid topologies using DC power flows

    CERN Document Server

    Spiewak, Russell; Forman, Yakir; Soltan, Saleh; Zussman, Gil

    2016-01-01

    Using the linearized DC power flow model, we study cascading failures and their spatial and temporal properties in the US Western Interconnect (USWI) power grid. We also introduce the preferential Degree And Distance Attachment (DADA) model, with similar degree distributions, resistances, and currents to the USWI. We investigate the behavior of both grids resulting from the failure of a single line. We find that the DADA model and the USWI model react very similarly to that failure, and that their blackout characteristics resemble each other. In many cases, the failure of a single line can cause cascading failures, which impact the entire grid. We characterize the resilience of the grid by three parameters, the most important of which is tolerance ${\\alpha}$, which is the ratio of the maximal load a line can carry to its initial load. We characterize a blackout by its yield, which we define as the ratio of the final to the initial consumed currents. We find that if ${\\alpha}\\leq2$, the probability of a large ...

  20. 基于“站-线-变-户”电网模型的预约停电管理模型设计%Appointment power outage management business model design based on “Station - line - change - households” grid model

    Institute of Scientific and Technical Information of China (English)

    于涛

    2014-01-01

    Based oninformation integration camp with "Station - line - change - households" grid model, appointment blackout that allow customers to participate in the development of power cut scheme will be performed in the power supply enterprise customer information and interaction platform.Establish an appointment outage management model, namely screening appointment blackout customers,select the best service channels to communicate with customers,pooled analysis of customer feedback across channels,and develop optimal algorithm to formulate an optimal power cut scheme.%本文基于营配信息集成“站-线-变-户”电网模型,让客户参与停电计划的制定,在供电企业客服信息与互动平台实行预约停电。建立预约停电管理模型,即筛选预约停电客户群,选择最佳服务渠道与客户进行沟通,汇集分析各渠道客户的意见,通过算法处理制定最优的停电计划。

  1. 应对连锁故障的广域协同预控制系统研究%Research on Wide Area Cooperative Precontrol System for Cascading Failure

    Institute of Scientific and Technical Information of China (English)

    许婧; 白晓民; 黄镔

    2013-01-01

    Major blackouts caused by cascading failure experienced an observable process of equipment outages. Blackout could be avoided if reasonable control measures were taken during that period. Started from the experience of electric power construction in China for many years and used multi-Agent system theory for reference, a wide area cooperative precontrol system framework based on off-line analysis of cross-section power transfer limit is presented in this paper, which is feasible for engineering practice. Case study shows that the wide area cooperative precontrol system can prevent grid instability triggered by cascading failure occurring in local area.%由连锁故障导致的大停电多数经历了一个明显的故障发生发展的过程,在此期间如采取合理控制措施,有可能避免大停电的发生.从我国多年电力建设的经验出发,借鉴多智能体系统理论,提出了具有工程实践意义的,基于“离线断面功率传输极限分析”的广域协同预控制系统框架.算例结果表明,该系统对局部区域连锁故障可能导致的全网失稳起到预防的作用.

  2. An analysis on the severe accident progression with operator recovery actions

    Energy Technology Data Exchange (ETDEWEB)

    Vo, T.H. [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejon 305-353 (Korea, Republic of); Korea University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Song, J.H., E-mail: dosa@kaeri.re.kr [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejon 305-353 (Korea, Republic of); Korea University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Kim, T.W.; Kim, D.H. [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejon 305-353 (Korea, Republic of)

    2014-12-15

    Highlights: • Severe accident progression for the station blackout and SBLOCA accident. • Analyses on APR1400 using MELCOR. • Operator recovery actions for decay heat removal and inventory make up. • Determine the time allowed for the operator to prevent reactor vessel failure. • Insight for the operator recovery actions for the severe accident management. - Abstract: Analyses on the severe accident progressions for the station blackout (SBO) accident and small break LOCA (SBLOCA) initiated severe accident were performed for APR1400 by using MELCOR computer code. Operator recovery actions for decay heat removal and inventory make up using a depressurization system and safety injection pump were simulated in parallel with a simulation of the severe accident progression. Sensitivity studies on the operator actions were performed to investigate the changes in the timing of the reactor vessel failure and to determine the time allowed for the operator to prevent reactor vessel failure. Sensitivity analyses on the effect of major modeling parameters were performed additionally to quantify the uncertainties in timing. It is found that the operator has about 2 h for the recovery actions after the indication of core damage by the signal of core exit thermocouple (CET) for the SBLOCA initiated severe accident, while the operator has to take immediate actions after the indication of core damage by CET for the SBO accident.

  3. Vegetation Height Estimation Near Power transmission poles Via satellite Stereo Images using 3D Depth Estimation Algorithms

    Science.gov (United States)

    Qayyum, A.; Malik, A. S.; Saad, M. N. M.; Iqbal, M.; Abdullah, F.; Rahseed, W.; Abdullah, T. A. R. B. T.; Ramli, A. Q.

    2015-04-01

    Monitoring vegetation encroachment under overhead high voltage power line is a challenging problem for electricity distribution companies. Absence of proper monitoring could result in damage to the power lines and consequently cause blackout. This will affect electric power supply to industries, businesses, and daily life. Therefore, to avoid the blackouts, it is mandatory to monitor the vegetation/trees near power transmission lines. Unfortunately, the existing approaches are more time consuming and expensive. In this paper, we have proposed a novel approach to monitor the vegetation/trees near or under the power transmission poles using satellite stereo images, which were acquired using Pleiades satellites. The 3D depth of vegetation has been measured near power transmission lines using stereo algorithms. The area of interest scanned by Pleiades satellite sensors is 100 square kilometer. Our dataset covers power transmission poles in a state called Sabah in East Malaysia, encompassing a total of 52 poles in the area of 100 km. We have compared the results of Pleiades satellite stereo images using dynamic programming and Graph-Cut algorithms, consequently comparing satellites' imaging sensors and Depth-estimation Algorithms. Our results show that Graph-Cut Algorithm performs better than dynamic programming (DP) in terms of accuracy and speed.

  4. The Reliability Value of Storage in a Volatile Environment

    CERN Document Server

    ParandehGheibi, Ali; Ozdaglar, Asuman; Dahleh, Munther A

    2011-01-01

    This paper examines the value of storage in securing reliability of a system with uncertain supply and demand, and supply friction. The storage is frictionless as a supply source, but once used, it cannot be filled up instantaneously. The focus application is a power supply network in which the base supply and demand are assumed to match perfectly, while deviations from the base are modeled as random shocks with stochastic arrivals. Due to friction, the random surge shocks cannot be tracked by the main supply sources. Storage, when available, can be used to compensate, fully or partially, for the surge in demand or loss of supply. The problem of optimal utilization of storage with the objective of maximizing system reliability is formulated as minimization of the expected discounted cost of blackouts over an infinite horizon. It is shown that when the stage cost is linear in the size of the blackout, the optimal policy is myopic in the sense that all shocks are compensated by storage up to the available level...

  5. Vehicle routing for the last mile of power system restoration

    Energy Technology Data Exchange (ETDEWEB)

    Bent, Russell W [Los Alamos National Laboratory; Coffrin, Carleton [Los Alamos National Laboratory; Van Hentenryck, Pascal [BROWN UNIV.

    2010-11-23

    This paper studied a novel problem in power system restoration: the Power Restoration Vehicle Routing Problem (PRVRP). The goal of PRVRPs is to decide how coordinate repair crews effectively in order to recover from blackouts as fast as possible after a disaster has occurred. PRVRPs are complex problems that combine vehicle routing and power restoration scheduling problems. The paper proposed a multi-stage optimization algorithm based on the idea of constraint injection that meets the aggressive runtime constraints necessary for disaster recovery. The algorithms were validated on benchmarks produced by the Los Alamos National Laboratory, using the infrastructure of the United States. The disaster scenarios were generated by state-of-the-art hurricane simulation tools similar to those used by the National Hurricane Center. Experimental results show that the constraint-injection algorithms can reduce the blackouts by 50% or more over field practices. Moreover, the results show that the constraint-injection algorithm using large neighborhood search over a blackbox simulator provide competitive quality and scales better than using a MIP solver on the subproblems.

  6. Schemes for protecting electric power systems; Esquemas de protecao de sistemas de energia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Paulo Cesar de

    2002-07-01

    The objective of this dissertation is to accomplish an introduction to the studies and the applications of the System Protection Schemes (SPS) used to maintain the electric power systems safety. A small group of definitions and concepts from the 'protection, reliability and power systems performance analysis' areas is presented with the objective of distinguishing SPS from the conventional system component protections. It also helps in understanding the functions of the SPS with more clarity. The SPS are used to maintain the integrity of the system when it is submitted to phenomena that provoke instability or cascade circuit outages. The classification and the description of these phenomena, as well as the SPS application are shown in this dissertation. The general structure of the SPS, the ways of classifying them and the different actions used by SPS to control the disturbances are the objectives of the analysis of this work. In order to exemplify, a vision is given of how the SPS are located in the Brazilian interconnected system (BIS) and also in the rest of the world. Some SPS used in Brazil deserved special attention. The analyses of the main blackouts that occurred in Brazil and in North America are presented, in a summarized term, in appendix I. Considerable knowledge is obtained from these analyses, leading to implementation measures that minimize the risk of interruptions in the energy supply. A comparison is also made of the degree of severity of the great blackouts that happened in Brazil and, for the two largest, an estimate of their respective interruption costs is made. In appendix II, an attempt was also made to establish the basic requirements for the SPS implementation using micro processing technology. Based on the experience lived during the studies developed by the group that analyzed the safety of the Bis after the blackout on March 11/1999, criteria and procedures to analyze the safety of the system and to accomplish studies of SPS

  7. Margin and sensitivity methods for security analysis of electric power systems

    Science.gov (United States)

    Greene, Scott L.

    Reliable operation of large scale electric power networks requires that system voltages and currents stay within design limits. Operation beyond those limits can lead to equipment failures and blackouts. Security margins measure the amount by which system loads or power transfers can change before a security violation, such as an overloaded transmission line, is encountered. This thesis shows how to efficiently compute security margins defined by limiting events and instabilities, and the sensitivity of those margins with respect to assumptions, system parameters, operating policy, and transactions. Security margins to voltage collapse blackouts, oscillatory instability, generator limits, voltage constraints and line overloads are considered. The usefulness of computing the sensitivities of these margins with respect to interarea transfers, loading parameters, generator dispatch, transmission line parameters, and VAR support is established for networks as large as 1500 buses. The sensitivity formulas presented apply to a range of power system models. Conventional sensitivity formulas such as line distribution factors, outage distribution factors, participation factors and penalty factors are shown to be special cases of the general sensitivity formulas derived in this thesis. The sensitivity formulas readily accommodate sparse matrix techniques. Margin sensitivity methods are shown to work effectively for avoiding voltage collapse blackouts caused by either saddle node bifurcation of equilibria or immediate instability due to generator reactive power limits. Extremely fast contingency analysis for voltage collapse can be implemented with margin sensitivity based rankings. Interarea transfer can be limited by voltage limits, line limits, or voltage stability. The sensitivity formulas presented in this thesis apply to security margins defined by any limit criteria. A method to compute transfer margins by directly locating intermediate events reduces the total number

  8. 低压故障停电报警系统%Low Pressure Fault Outage Alarm System

    Institute of Scientific and Technical Information of China (English)

    熊俊锋; 丁月明

    2013-01-01

      供电可靠性要求越来越高,对低压配电线路的供电情况一直缺乏监测,不能随时掌握台变的运行情况,如果台变发生跳闸事故,只能通过用户打电话通知电力部门,经常出现停电后不能得到即时地处理,给用户带来工作、生活的不便,长时间的停电也会带来很大的经济损失。分析发生故障停电后报修不及时的原因和对策,研制了一套低压停电故障报警监测系统,在台变跳闸停电后能够通知电力抢修部门,使故障停电报修的时间尽可能的缩短,有效的减少了故障停电时间,提高了供电可靠性,同时有效地提高了供电企业的优质服务水平。%There is higher demand for supply reliability. There is not enough monitoring of the supply of low-voltage distribution lines, and so we can not keep up operation of bench transformer. If the bench transformer occurs tripping accident, we can notify the power sector only through user's call. If the blackouts are often and can not be immediately treated, it will bring inconveniences to the work and living of the user, and also will bring great economic losses. This paper analyzed the causes and countermeasures for not timely repair to failure blackout, developed a set of low-voltage power failure alarm monitoring system which can send the tripping blackout to electrical repair department, reduce the repair time and effectively reduce the fault outage time, improve the reliability of power supply, at the same time improve the level of quality service of power supply enterprise.

  9. Anticipating Interruptions. Security and risk in a liberalized electricity infrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Silvast, A.

    2013-11-01

    During the past ten years, a number of social scientists have emphasized the importance of material infrastructures like electricity supply as a research topic for the social sciences. The developing of such new perspectives concerning infrastructures also includes uncertainties and risks. This research analyzes the management of uncertainties in the Finnish electricity infrastructure by posing the following research question: how are electricity interruptions, or blackouts, anticipated in Finland and how are these interruptions managed as risks? The main research methodology of the work is multi-sited field work. The empirical materials include interviews with experts and lay people (33 interviews); participant observation in two electricity control rooms; an electricity consumer survey (115 respondents); and also a number of infrastructure and security policy documents and observations from electricity security seminars. The materials were primarily gathered between 2004 and 2008. Social science research often links risks with major current social changes or socio-cultural risk perceptions. In recent international social science discussions, however, a new research topic has emerged - those styles of reasoning and techniques of governance that are deployed to manage risk as a practical matter. My study explores these themes empirically by focusing on the specific habitual practices of risk management in the Finnish electricity infrastructure. The work develops various also semi-ethnographic inquiries into infrastructure risk techniques like monitor screening of real-time risks in electricity control rooms; the management of risks in a liberalized electricity market; the emergence of Finnish reasoning about blackouts from a specific historical background; and the ways in which electricity consumers respond to blackouts in their homes. In addition, the work reflects upon the position of a risk researcher in those situations when the research subjects do not define

  10. Transmission Properties of Radar Wave through Reentry Plasma Sheath

    Institute of Scientific and Technical Information of China (English)

    GAO Zheng-ping; MA Zhao-guo; LIU Jing; LI Zhong-ping; ZHANG Da-hai

    2007-01-01

    In this paper, by taking into account the coupling of the ionization of ablation gas and atmosphere, an electrons density distribution model is built. Using this model, the transmission properties of different polarization radar wave through sheath are evaluated on the basis of the transmission matrix theory. Then, we discuss the effects of the electrons density, the added magnetic field, and the radar wave frequency on the transmission properties. As a result of this investigation,greater transmission power could be gained in order to efficiently shorten communication blackout,by reducing the electrons density or choosing proper added magnetic field and the frequency of the radar wave according to the different polarization form of the radar wave.

  11. Risk energy transition. Ways out of the impasse; Risiko Energiewende. Wege aus der Sackgasse

    Energy Technology Data Exchange (ETDEWEB)

    Kleinknecht, Konrad [Muenchen Univ., Garching (Germany). Fakultaet fuer Physik

    2015-07-01

    The exit of the use of nuclear energy in Germany, it was decided in the summer of 2011 in a rush. Now it is becoming obvious that there is no realistic plan for the conversion of energy supply in the envisaged deadline of ten years. For the conversion of our entire power supply and therefore our economy the period is too short. It lacks a robust empirical reason that have to deal with the issues of security of supply, the affordability, the impact on economic development and social justice. Thus, this treansition threatens to fail at their contradictions. Konrad Kleinknecht tries in his book, to name the problems and to find answers. For him, arise the following questions: What are our opportunity to replace with wind and solar power to replace a part of the power supply? What power sources provide secured capacity? Can we dispense with coal-fired plants? Do we need new power lines? How power may be stored? How real is the risk of blackouts in windless nights? Will the power prices continue to rise? Can be avoided the major risks of the energy transition with a fundamental reform of the Renewable Energies Act (EEG)? The power supply must serve the common good and benefit the industrial site Germany. A blackout would be a disaster for the whole country, it must be avoided at all events. How can we manage this, the author present in his evocative book. [German] Der Ausstieg aus der Nutzung der Kernenergie in Deutschland wurde im Sommer 2011 im Eiltempo beschlossen. Jetzt zeigt sich, dass es keinen realistischen Plan fuer den Umbau der Energieversorgung in der vorgesehenen Frist von zehn Jahren gibt. Fuer die Umstellung unserer gesamten Stromversorgung und damit unserer Wirtschaft ist der Zeitraum zu kurz. Es fehlt eine belastbare empirische Begruendung, die Fragen der Versorgungssicherheit, der Finanzierbarkeit, der Auswirkungen auf die wirtschaftliche Entwicklung und die soziale Gerechtigkeit behandeln muesste. Somit droht diese Wende an ihren Widerspruechen zu

  12. Contributing and consequential correlates of illicit substance use among students

    Directory of Open Access Journals (Sweden)

    Rehana Khalil

    2015-12-01

    Conclusions: It was found that majority of the respondents' friends were involved in drug use and less commonly their cousins and family members. Most of them started drug consumption at age between 15-19 years and were mainly doing it for recreational purposes; other reasons were social pressure or educational stress. The consequential correlates identified includes, behavioural attributes distorted relationship with family and friends, poor performance in education, and delinquent activities like imprisonment and other unlawful pursuits. Other attributes were medical including physical manifestation of substance abuse like blackouts, hepatitis B and C, increased heart rate, convulsions and lung infections. The psychological manifestations listed depression and anxiety, and impaired memory. [Int J Res Med Sci 2015; 3(12.000: 3446-3451

  13. On engineering implementation of the digital power system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The narrow definition of the digital power system (DPS) is proposed. The architec- ture, features and key contents of the DPS are presented, which include intelligent dispatching system, hybrid automatic control system and data sharing platform. The successful construction of the DPS can greatly improve the performances of power system operating and dispatching, which mainly reflect a fundamental in- crease of the ability of avoiding catastrophes resulting from blackouts of power supply, a significant improvement of economic efficiency of power system opera- tion, and an improvement of decision efficiency of power system developing. The DPS describes a vision of the development of power system and the way to achieve this vision. At the same time, the paper also proposes the principles of the design and implementation of the DPS.

  14. On engineering implementation of the digital power system

    Institute of Scientific and Technical Information of China (English)

    HE GuangYu; SUN YingYu; CHANG NaiChao; MEI ShengWei

    2008-01-01

    The narrow definition of the digital power system (DPS) is proposed. The architec-ture, features and key contents of the DPS are presented, which include intelligent dispatching system, hybrid automatic control system and data sharing platform. The successful construction of the DPS can greatly improve the performances of power system operating and dispatching, which mainly reflect s fundamental in-crease of the ability of avoiding catastrophes resulting from blackouts of power supply, a significant improvement of economic efficiency of power system opera-tion, and an improvement of decision efficiency of power system developing. The DPS describes a vision of the development of power system end the way to achieve this vision. At the same time, the paper also proposes the principles of the design and implementation of the DPS.

  15. The electricity; market, investments and security of supply; La electricidad: Mercado, inversiones y garantia de suministro

    Energy Technology Data Exchange (ETDEWEB)

    Fabra, N.

    2007-07-01

    In this paper we discuss some of the special features of electricity that should be taken into account when assessing investment incentives, giving special emphasis to the role played by firms strategic behaviour. Furthermore, we assess the potential for some regulatory instruments to induce firms to undertake the efficient investments in the marketplace. In particular, some of the questions that this paper discusses are the following: Is the market alone the best mechanism to induce the right investment levels? How does the public good nature of security of supply interact with the provision of generation capacity? Are there regulatory measures to improve investment choices, reducing both the risk of blackouts as well as inefficient over investment?. (Author). 12 refs.

  16. Updated Peach Bottom Model for MELCOR 1.8.6: Description and Comparisons

    Energy Technology Data Exchange (ETDEWEB)

    Robb, Kevin R [ORNL

    2014-09-01

    A MELCOR 1.8.5 model of the Peach Bottom Unit 2 or 3 has been updated for MELCOR 1.8.6. Primarily, this update involved modification of the lower head modeling. Three additional updates were also performed. First, a finer nodalization of the containment wet well was employed. Second, the pressure differential used by the logic controlling the safety relief valve actuation was modified. Finally, an additional stochastic failure mechanism for the safety relief valves was added. Simulation results from models with and without the modifications were compared. All the analysis was performed by comparing key figures of merit from simulations of a long-term station blackout scenario. This report describes the model changes and the results of the comparisons.

  17. The equal load-sharing model of cascade failures in power grids

    CERN Document Server

    Scala, Antonio

    2015-01-01

    Electric power-systems are one of the most important critical infrastructures. In recent years, they have been exposed to extreme stress due to the increasing demand, the introduction of distributed renewable energy sources, and the development of extensive interconnections. We investigate the phenomenon of abrupt breakdown of an electric power-system under two scenarios: load growth (mimicking the ever-increasing customer demand) and power fluctuations (mimicking the effects of renewable sources). Our results indicate that increasing the system size causes breakdowns to become more abrupt; in fact, mapping the system to a solvable statistical-physics model indicates the occurrence of a first order transition in the large size limit. Such an enhancement for the systemic risk failures (black-outs) with increasing network size is an effect that should be considered in the current projects aiming to integrate national power-grids into "super-grids".

  18. The equal load-sharing model of cascade failures in power grids

    Science.gov (United States)

    Scala, Antonio; De Sanctis Lucentini, Pier Giorgio

    2016-11-01

    Electric power-systems are one of the most important critical infrastructures. In recent years, they have been exposed to extreme stress due to the increasing power demand, the introduction of distributed renewable energy sources, and the development of extensive interconnections. We investigate the phenomenon of abrupt breakdown of an electric power-system under two scenarios: load growth (mimicking the ever-increasing customer demand) and power fluctuations (mimicking the effects of renewable sources). Our results indicate that increasing the system size causes breakdowns to become more abrupt; in fact, mapping the system to a solvable statistical-physics model indicates the occurrence of a first order transition in the large size limit. Such an enhancement for the systemic risk failures (black-outs) with increasing network size is an effect that should be considered in the current projects aiming to integrate national power-grids into "super-grids".

  19. Transient time period analysis of smooth handoffs in mobile IP networks and its application to media streaming

    Science.gov (United States)

    Lee, Dongwook; Kim, JongWon

    2003-11-01

    Streaming media applications over mobile IP networks suffer from playback disruptions resulting from handoff blackout period as well as bandwidth fluctuation. To overcome buffer shortage, pre-buffering technique can be adopted where the client stores sufficient amount of stream in advance. However, under the mobile IP handoff that may take up to several seconds, it is extremely difficult to sustain seamless playback. Inaccurate and conservative choice on the required buffering size can waste limited latency budget, resulting in quality degradation. In this paper, we are extending--from smooth handoff to fast handoff of mobile IPv6--the transient time analysis recently proposed to approximate transient time durations, STP (silent time period) and UTP (unstable time period). The approximated time periods are utilized to estimate the required buffering buffer size accurately. Network simulation result evaluted under simplified buffering strategies shows that the proposed scheme can provide appropriate guideline on the buffer parameters and thus can improve seamless streaming.

  20. Optimizing the robustness of electrical power systems against cascading failures

    CERN Document Server

    Zhang, Yingrui

    2016-01-01

    Electrical power systems are one of the most important infrastructures that support our society. However, their vulnerabilities have raised great concern recently due to several large-scale blackouts around the world. In this paper, we investigate the robustness of power systems against cascading failures initiated by a random attack. This is done under a simple yet useful model based on global and equal redistribution of load upon failures. We provide a complete understanding of system robustness by i) deriving an expression for the final system size as a function of the size of initial attacks; ii) deriving the critical attack size after which system breaks down completely; iii) showing that complete system breakdown takes place through a first-order (i.e., discontinuous) transition in terms of the attack size; and iv) establishing the optimal load-capacity distribution that maximizes robustness. In particular, we show that robustness is maximized when the difference between the capacity and initial load is...

  1. Conjugate heat transfer analysis of multiple enclosures in prototype fast breeder reactor

    Energy Technology Data Exchange (ETDEWEB)

    Velusamy, K.; Balaubramanian, V.; Vaidyanathan, G.; Chetal, S.C. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    1995-09-01

    Prototype Fast Breeder Reactor (PFBR) is a 500 MWe sodium cooled reactor under design. The main vessel of the reactor serves as the primary boundary. It is surrounded by a safety vessel which in turn is surrounded by biological shield. The gaps between them are filled with nitrogen. Knowledge of temperature distribution prevailing under various operating conditions is essential for the assessment of structural integrity. Due to the presence of cover gas over sodium free level within the main vessel, there are sharp gradients in temperatures. Also cover gas height reduces during station blackout conditions due to sodium level rise in main vessel caused by temperature rise. This paper describes the model used to analyse the natural convection in nitrogen, conduction in structures and radiation interaction among them. Results obtained from parametric studies for PFBR are also presented.

  2. Comparison of a Traditional Probabilistic Risk Assessment Approach with Advanced Safety Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Curtis L; Mandelli, Diego; Zhegang Ma

    2014-11-01

    As part of the Light Water Sustainability Program (LWRS) [1], the purpose of the Risk Informed Safety Margin Characterization (RISMC) [2] Pathway research and development (R&D) is to support plant decisions for risk-informed margin management with the aim to improve economics, reliability, and sustain safety of current NPPs. In this paper, we describe the RISMC analysis process illustrating how mechanistic and probabilistic approaches are combined in order to estimate a safety margin. We use the scenario of a “station blackout” (SBO) wherein offsite power and onsite power is lost, thereby causing a challenge to plant safety systems. We describe the RISMC approach, illustrate the station blackout modeling, and contrast this with traditional risk analysis modeling for this type of accident scenario. We also describe our approach we are using to represent advanced flooding analysis.

  3. Intelligent decision support algorithm for distribution system restoration.

    Science.gov (United States)

    Singh, Reetu; Mehfuz, Shabana; Kumar, Parmod

    2016-01-01

    Distribution system is the means of revenue for electric utility. It needs to be restored at the earliest if any feeder or complete system is tripped out due to fault or any other cause. Further, uncertainty of the loads, result in variations in the distribution network's parameters. Thus, an intelligent algorithm incorporating hybrid fuzzy-grey relation, which can take into account the uncertainties and compare the sequences is discussed to analyse and restore the distribution system. The simulation studies are carried out to show the utility of the method by ranking the restoration plans for a typical distribution system. This algorithm also meets the smart grid requirements in terms of an automated restoration plan for the partial/full blackout of network.

  4. The New Core Value to Be Bu Built:Customer's Interests-The Final Mission

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ In January of 2008 a rare calamity occurred,i.e.,a wide-spread snow storm hit southeast and southwest provinces of China.Tens thousands of transmission lines were interrupted,and tens thousands of towers frosted up and collapsed.Traffic stopped.Blackout occurred in many regions.14 workers died in accidents while repairing the power transmission facilities. All Chinese,including the top leaders of CPC and Chinese government,were worried about the victims of the disaster. Obviously,it is not enough to think about only improving the power line design standards and other technological measures.A structural and systematic analysis shall be made at a level of the core value of electric industry.

  5. Using SDO-EVE Satellite Data to Model for the First Time how Large Solar Flares Influence the Earths Ionosphere

    Science.gov (United States)

    Jensen, Joseph; Sojka, Jan; Schunk, Robert; David, Michael; Woods, Tom; Eparvier, Frank

    2012-10-01

    The earth's ionosphere is very important in our everyday life. During large solar flares the ionosphere expands to the point of disrupting communications from GPS, military, and commercial communications satellites, and even radio blackouts can occur. The EVE instrument on the SDO satellite has given unprecedented spectral resolution for the Extreme Ultraviolet(EUV) spectrum with a time cadence of 10 seconds. This has made it possible to analyze flare spectra as never before. Using the Time Dependent Ionospheric Model (TDIM) we have input this new spectral data for large solar flares and analyzed the effect on the ionosphere. We take as a test case the X1.6 flare on March 9, 2011. Even this minor X-class provides insight into how the ionospheric layers respond differently to solar flares.

  6. Energy solutions for sustainable development. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Soenderberg Petersen, L.; Larsen, Hans (eds.)

    2007-05-15

    The Risoe International Energy Conference took place 22 - 24 May 2007. The conference focused on: 1) Future global energy development options. 2) Scenario and policy issues. 3) Measures to achieve low-level stabilization at, for example, 500 ppm CO2 concentrations in the atmosphere. 4) Local energy production technologies such as fuel cells, hydrogen, bio-energy and wind energy. 5) Centralized energy technologies such as clean coal technologies. 6) Providing renewable energy for the transport sector. 7) Systems aspects, differences between the various major regions throughout the world. 8) End-use technologies, efficiency improvements and supply links. 9) Security of supply with regard to resources, conflicts, black-outs, natural disasters and terrorism. (au)

  7. High performance robotic traverse of desert terrain.

    Energy Technology Data Exchange (ETDEWEB)

    Whittaker, William (Carnegie Mellon University, Pittsburgh, PA)

    2004-09-01

    This report presents tentative innovations to enable unmanned vehicle guidance for a class of off-road traverse at sustained speeds greater than 30 miles per hour. Analyses and field trials suggest that even greater navigation speeds might be achieved. The performance calls for innovation in mapping, perception, planning and inertial-referenced stabilization of components, hosted aboard capable locomotion. The innovations are motivated by the challenge of autonomous ground vehicle traverse of 250 miles of desert terrain in less than 10 hours, averaging 30 miles per hour. GPS coverage is assumed to be available with localized blackouts. Terrain and vegetation are assumed to be akin to that of the Mojave Desert. This terrain is interlaced with networks of unimproved roads and trails, which are a key to achieving the high performance mapping, planning and navigation that is presented here.

  8. Development of a Sequential Restoration Strategy Based on the Enhanced Dijkstra Algorithm for Korean Power Systems

    Directory of Open Access Journals (Sweden)

    Bokyung Goo

    2016-12-01

    Full Text Available When a blackout occurs, it is important to reduce the time for power system restoration to minimize damage. For fast restoration, it is important to reduce taking time for the selection of generators, transmission lines and transformers. In addition, it is essential that a determination of a generator start-up sequence (GSS be made to restore the power system. In this paper, we propose the optimal selection of black start units through the generator start-up sequence (GSS to minimize the restoration time using generator characteristic data and the enhanced Dijkstra algorithm. For each restoration step, the sequence selected for the next start unit is recalculated to reflect the system conditions. The proposed method is verified by the empirical Korean power systems.

  9. Vulnerability and Cosusceptibility Determine the Size of Network Cascades

    Science.gov (United States)

    Yang, Yang; Nishikawa, Takashi; Motter, Adilson E.

    2017-01-01

    In a network, a local disturbance can propagate and eventually cause a substantial part of the system to fail in cascade events that are easy to conceptualize but extraordinarily difficult to predict. Here, we develop a statistical framework that can predict cascade size distributions by incorporating two ingredients only: the vulnerability of individual components and the cosusceptibility of groups of components (i.e., their tendency to fail together). Using cascades in power grids as a representative example, we show that correlations between component failures define structured and often surprisingly large groups of cosusceptible components. Aside from their implications for blackout studies, these results provide insights and a new modeling framework for understanding cascades in financial systems, food webs, and complex networks in general.

  10. Visual symptoms and G-induced loss of consciousness in 594 Chinese Air Force aircrew--a questionnaire survey.

    Science.gov (United States)

    Cao, Xin-Sheng; Wang, Yong-Chun; Xu, Li; Yang, Chang-Bing; Wang, Bing; Geng, Jie; Gao, Yuan; Wu, Yan-Hong; Wang, Xiao-Ying; Zhang, Shu; Sun, Xi-Qing

    2012-02-01

    A questionnaire survey was performed for the first time to assess the prevalence of visual symptoms and G-induced loss of consciousness (G-LOC) due to +Gz exposure in the Chinese Air Force (CAF) to determine the effectiveness of current G tolerance training. Responses were received from 594 individuals. Among them, 302 reported at least one episode of some sort of symptoms related to +Gz, including 110 (18.5%) with visual blurring, 231 (38.9%) with greyout, 111 (18.7%) with blackout, and 49 (8.2%) with G-LOC. Incidences were most common in aircrew with 250-1,000 flying hours (53.6%) and were more prevalent in those with fewer on type flying hours (p aircrew. There remains considerable scope for +Gz education, particularly in the early centrifuge training and selection of rational physical exercises.

  11. Study on the electromagnetic waves propagation characteristics in partially ionized plasma slabs

    Directory of Open Access Journals (Sweden)

    Zhi-Bin Wang

    2016-05-01

    Full Text Available Propagation characteristics of electromagnetic (EM waves in partially ionized plasma slabs are studied in this paper. Such features are significant to applications in plasma antennas, blackout of re-entry flying vehicles, wave energy injection to plasmas, and etc. We in this paper developed a theoretical model of EM wave propagation perpendicular to a plasma slab with a one-dimensional density inhomogeneity along propagation direction to investigate essential characteristics of EM wave propagation in nonuniform plasmas. Particularly, the EM wave propagation in sub-wavelength plasma slabs, where the geometric optics approximation fails, is studied and in comparison with thicker slabs where the geometric optics approximation applies. The influences of both plasma and collisional frequencies, as well as the width of the plasma slab, on the EM wave propagation characteristics are discussed. The results can help the further understanding of propagation behaviours of EM waves in nonuniform plasma, and applications of the interactions between EM waves and plasmas.

  12. Security of the French electric systems after the 1999 storms; La securisation du systeme electrique francais apres les tempetes de 1999

    Energy Technology Data Exchange (ETDEWEB)

    Piketty, G. [Ecole Nationale Superieure des Mines, 75 - Paris (France)

    2002-08-01

    Given the costs of damages to the power grid during the storms of 26 and 28 December 1999, and for reasons related to EdF's image as a 'public service, it was necessary to carefully reexamine the level of security of various parts of the system in coping with events of an unprecedented violence and scope. The state has the responsibility of setting penalties (rate rebates) in the case of a prolonged blackout and the procedures for applying them. But it must also specify the order of magnitude and length of time for the program that it wants implemented to deal with such emergencies. It can do this by laying down general guidelines for investments in each major part of the electricity grid. (author)

  13. Reliability of emergency ac power systems at nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Battle, R E; Campbell, D J

    1983-07-01

    Reliability of emergency onsite ac power systems at nuclear power plants has been questioned within the Nuclear Regulatory Commission (NRC) because of the number of diesel generator failures reported by nuclear plant licensees and the reactor core damage that could result from diesel failure during an emergency. This report contains the results of a reliability analysis of the onsite ac power system, and it uses the results of a separate analysis of offsite power systems to calculate the expected frequency of station blackout. Included is a design and operating experience review. Eighteen plants representative of typical onsite ac power systems and ten generic designs were selected to be modeled by fault trees. Operating experience data were collected from the NRC files and from nuclear plant licensee responses to a questionnaire sent out for this project.

  14. Con Edison power failure of July 13 and 14, 1977. Final staff report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-06-01

    On July 13, 1977 the entire electric load of the Con Edison system was lost, plunging New York City and Westchester County into darkness. The collapse resulted from a combination of natural events, equipment malfunctions, questionable system-design features, and operating errors. An attempt is made in this report to answer the following: what were the specific causes of the failure; if equipment malfunctions and operator errors contributed, could they have been prevented; to what extent was Con Edison prepared to handle such an emergency; and did Con Edison plan prudently reserve generation, for reserve transmission capability, for automatic equipment to protect its system, and for proper operator response to a critical situation. Following the introductory and summary section, additional sections include: the Consolidated Edison system; prevention of bulk power-supply interruptions; the sequence of failure and restoration; analysis of the July 1977 power failure; restoration sequence and equipment damage assessment; and other investigations of the blackout. (MCW)

  15. Leak rate analysis of the Westinghouse Reactor Coolant Pump

    Energy Technology Data Exchange (ETDEWEB)

    Boardman, T.; Jeanmougin, N.; Lofaro, R.; Prevost, J.

    1985-07-01

    An independent analysis was performed by ETEC to determine what the seal leakage rates would be for the Westinghouse Reactor Coolant Pump (RCP) during a postulated station blackout resulting from loss of ac electric power. The object of the study was to determine leakage rates for the following conditions: Case 1: All three seals function. Case 2: No. 1 seal fails open while Nos. 2 and 3 seals function. Case 3: All three seals fail open. The ETEC analysis confirmed Westinghouse calculations on RCP seal performance for the conditions investigated. The leak rates predicted by ETEC were slightly lower than those predicted by Westinghouse for each of the three cases as summarized below. Case 1: ETEC predicted 19.6 gpm, Westinghouse predicted 21.1 gpm. Case 2: ETEC predicted 64.7 gpm, Westinghouse predicted 75.6 gpm. Case 3: ETEC predicted 422 gpm, Westinghouse predicted 480 gpm. 3 refs., 22 figs., 6 tabs.

  16. Robustness Area Technique Developing Guidelines for Power System Restoration

    Directory of Open Access Journals (Sweden)

    Paulo Murinelli Pesoti

    2017-01-01

    Full Text Available This paper proposes a novel energy based technique called the Robustness Area (RA technique that measures power system robustness levels, as a helper for planning Power System Restorations (PSRs. The motivation is on account of the latest blackouts in Brazil, where the local Independent System Operator (ISO encountered difficulties related to circuit disconnections during the restoration. The technique identifies vulnerable and robust buses, pointing out system areas that should be firstly reinforced during PSR, in order to enhance system stability. A Brazilian power system restoration area is used to compare the guidelines adopted by the ISO with a more suitable new plan indicated by the RA tool. Active power and reactive power load margin and standing phase angle show the method efficiency as a result of a well balanced system configuration, enhancing the restoration performance. Time domain simulations for loop closures and severe events also show the positive impact that the proposed tool brings to PSRs.

  17. Model Calibration of Exciter and PSS Using Extended Kalman Filter

    Energy Technology Data Exchange (ETDEWEB)

    Kalsi, Karanjit; Du, Pengwei; Huang, Zhenyu

    2012-07-26

    Power system modeling and controls continue to become more complex with the advent of smart grid technologies and large-scale deployment of renewable energy resources. As demonstrated in recent studies, inaccurate system models could lead to large-scale blackouts, thereby motivating the need for model calibration. Current methods of model calibration rely on manual tuning based on engineering experience, are time consuming and could yield inaccurate parameter estimates. In this paper, the Extended Kalman Filter (EKF) is used as a tool to calibrate exciter and Power System Stabilizer (PSS) models of a particular type of machine in the Western Electricity Coordinating Council (WECC). The EKF-based parameter estimation is a recursive prediction-correction process which uses the mismatch between simulation and measurement to adjust the model parameters at every time step. Numerical simulations using actual field test data demonstrate the effectiveness of the proposed approach in calibrating the parameters.

  18. Elimination of the Inrush Current Phenomenon Associated with Single-Phase Offline UPS Systems

    Directory of Open Access Journals (Sweden)

    Syed Sabir Hussain Bukhari

    2016-02-01

    Full Text Available Critical load applications always rely on UPS systems to uphold continuous power during abnormal grid conditions. In case of any power disruption, an offline UPS system starts powering the load to avoid blackout. However, this process can root the momentous inrush current for the transformer installed before the load. The consequences of inrush current can be the reduction of output voltage and tripping of protective devices of the UPS system. Furthermore, it can also damage the sensitive load and decrease the transformer’s lifetime. To prevent the inrush current, and to avoid its disruptive effects, this research suggests an offline UPS system based on a current regulated inverter that eliminates the inrush current while powering the transformer coupled loads. A detailed comparative analysis of the conventional and proposed topologies is presented and the experiment was performed by using a small prototype to validate the performance, and operation of the proposed topology.

  19. City of Hoboken Energy Surety Analysis: Preliminary Design Summary

    Energy Technology Data Exchange (ETDEWEB)

    Stamp, Jason Edwin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Military and Energy Systems Analysis Dept.; Baca, Michael J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Military and Energy Systems Analysis Dept.; Munoz-Ramos, Karina [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Military and Energy Systems Analysis Dept.; Schenkman, Benjamin L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Military and Energy Systems Analysis Dept.; Eddy, John P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Systems Readiness and Sustainment Technology Dept.; Smith, Mark A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Systems Readiness and Sustainment Technology Dept.; Guttromson, Ross [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Electric Power Systems Research Dept.; Henry, Jordan M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Critical Infrastructure Systems Dept.; Jensen, Richard Pearson [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.

    2014-09-01

    In 2012, Hurricane Sandy devastated much of the U.S. northeast coastal areas. Among those hardest hit was the small community of Hoboken, New Jersey, located on the banks of the Hudson River across from Manhattan. This report describes a city-wide electrical infrastructure design that uses microgrids and other infrastructure to ensure the city retains functionality should such an event occur in the future. The designs ensure that up to 55 critical buildings will retain power during blackout or flooded conditions and include analysis for microgrid architectures, performance parameters, system control, renewable energy integration, and financial opportunities (while grid connected). The results presented here are not binding and are subject to change based on input from the Hoboken stakeholders, the integrator selected to manage and implement the microgrid, or other subject matter experts during the detailed (final) phase of the design effort.

  20. A review of postural orthostatic tachycardia syndrome.

    LENUS (Irish Health Repository)

    Carew, Sheila

    2012-01-31

    A 21-year-old female reports an 18-month history of light-headedness on standing. This is often associated with palpitations and a feeling of intense anxiety. She has had two black-outs in the past 12 months. She is not taking any regular medications. Her supine blood pressure was 126\\/84 mmHg with a heart rate of 76 bpm, and her upright blood pressure was 122\\/80 mmHg with a heart rate of 114 bpm. A full system examination was otherwise normal. She had a 12-lead electrocardiogram performed which was unremarkable. She was referred for head-up tilt testing. She was symptomatic during the test and lost consciousness at 16 min. Figure 1 summarizes her blood pressure and heart rate response to tilting. A diagnosis of postural orthostatic tachycardia syndrome with overlapping vasovagal syncope was made.

  1. Optimal Management and Design of Energy Systems under Atmospheric Uncertainty

    Science.gov (United States)

    Anitescu, M.; Constantinescu, E. M.; Zavala, V.

    2010-12-01

    The generation and distpatch of electricity while maintaining high reliability levels are two of the most daunting engineering problems of the modern era. This was demonstrated by the Northeast blackout of August 2003, which resulted in the loss of 6.2 gigawatts that served more than 50 million people and which resulted in economic losses on the order of $10 billion. In addition, there exist strong socioeconomic pressures to improve the efficiency of the grid. The most prominent solution to this problem is a substantial increase in the use of renewable energy such as wind and solar. In turn, its uncertain availability—which is due to the intrinsic weather variability—will increase the likelihood of disruptions. In this endeavors of current and next-generation power systems, forecasting atmospheric conditions with uncertainty can and will play a central role, at both the demand and the generation ends. User demands are strongly correlated to physical conditions such as temperature, humidity, and solar radiation. The reason is that the ambient temperature and solar radiation dictate the amount of air conditioning and lighting needed in residential and commercial buildings. But these potential benefits would come at the expense of increased variability in the dynamics of both production and demand, which would become even more dependent on weather state and its uncertainty. One of the important challenges for energy in our time is how to harness these benefits while “keeping the lights on”—ensuring that the demand is satisfied at all times and that no blackout occurs while all energy sources are optimally used. If we are to meet this challenge, accounting for uncertainty in the atmospheric conditions is essential, since this will allow minimizing the effects of false positives: committing too little baseline power in anticipation of demand that is underestimated or renewable energy levels that fail to materialize. In this work we describe a framework for the

  2. Resistance to change as a function of concurrent reinforcer magnitude.

    Science.gov (United States)

    Rau, J C; Pickering, L D; McLean, A P

    1996-12-01

    Six pigeons responded on two keys in each of three signalled multiple-schedule components, and resistance to disruption of responding on one (target) key by extinction and by response-independent food presented during inter-component blackouts was studied. Alternative reinforcement of different magnitudes was contingent on pecking a non-target key in two components, and in the third only the target response was reinforced. Resistance to change varied with the overall quantity of reinforcement in the component, regardless of whether reinforcers were contingent on the target or non-target response, but did not differ across the two key locations. These results using different magnitudes of reinforcement confirm previous findings using rate of reinforcement as the variable, and suggest that resistance to change is dependent on stimulus-reinforcer rather than response-reinforcer contingencies.

  3. Dynamic Modeling of Cascading Failure in Power Systems

    CERN Document Server

    Song, Jiajia; Ghanavati, Goodarz; Hines, Paul D H

    2014-01-01

    The modeling of cascading failure in power systems is difficult because of the many different mechanisms involved; no single model captures all of these mechanisms. Understanding the relative importance of these different mechanisms is an important step in choosing which mechanisms need to be modeled for particular types of cascading failure analysis. This work presents a dynamic simulation model of both power networks and protection systems, which can simulate a wider variety of cascading outage mechanisms, relative to existing quasi-steady state (QSS) models. The model allows one to test the impact of different load models and protections on cascading outage sizes. This paper describes each module of the developed dynamic model and demonstrates how different mechanisms interact. In order to test the model we simulated a batch of randomly selected $N-2$ contingencies for several different static load configurations, and found that the distribution of blackout sizes and event lengths from the proposed dynamic...

  4. Cascading Power Outages Propagate Locally in an Influence Graph that is not the Actual Grid Topology

    CERN Document Server

    Hines, Paul D H; Rezaei, Pooya

    2015-01-01

    In a cascading power transmission outage, component outages propagate non-locally; after one component outages, the next failure may be very distant, both topologically and geographically. As a result, simple models of topological contagion do not accurately represent the propagation of cascades in power systems. However, cascading power outages do follow patterns, some of which are useful in understanding and reducing blackout risk. This paper describes a method by which the data from many cascading failure simulations can be transformed into a graph-based model of influences that provides actionable information about the many ways that cascades propagate in a particular system. The resulting "influence graph" model is Markovian, since component outage probabilities depend only on the outages that occurred in the prior generation. To validate the model we compare the distribution of cascade sizes resulting from n-2 contingencies in a 2896 branch test case to cascade sizes in the influence graph. The two dist...

  5. Continuation Power Flow Method based Assessment of Static Voltage Stability considering the Power System Contingencies

    Directory of Open Access Journals (Sweden)

    Khan Aafreen

    2014-11-01

    Full Text Available Power system security is recognized as one of the major problems in many power systems throughout the world. Power system insecurity such as transmission lines being overloaded causes transmission elements cascade outages, which may lead to complete blackout. In accordance with these reasons, the prediction and recognition of voltage instability in power system has particular importance and it makes the network security stronger. This work, by considering the power system contingencies based on the effects of them on Mega Watt Margin (MWM and maximum loading point (MLP is focused to analyse the voltage stability using continuation power flow method. The study has been carried out on IEEE 30-Bus Test System using MATLAB and PSAT softwares and results are presented.

  6. 10 kV Power Distribution Network Fault Cause Analysis and Countermeasures%10 kV配网故障停电原因分析及解决对策研究

    Institute of Scientific and Technical Information of China (English)

    麦浩明

    2014-01-01

    10 kV distribution network is a grassroots network of internal grid, which covers areas including urban, suburban and no mountain, maintenance more difficult, often malfunction, leading to blackouts. This paper analyzes the 10 kV distribution network outage causes and proposed solutions.%10 kV配网是电网内部的基层网络,其覆盖的地区包括城市、郊区和无人的山区,维护难度较大,经常发生故障,进而导致停电事故。简要分析了10 kV配网停电的原因,并提出了解决方案。

  7. A neural networks based ``trip`` analysis system for PWR-type reactors; Um sistema de analise de ``trip`` em reatores PWR usando redes neuronais

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Antonio Carlos Pinto Dias

    1993-12-31

    The analysis short after automatic shutdown (trip) of a PWR-type nuclear reactor takes a considerable amount of time, not only because of the great number of variables involved in transients, but also the various equipment that compose a reactor of this kind. On the other hand, the transients`inter-relationship, intended to the detection of the type of the accident is an arduous task, since some of these accidents (like loss of FEEDWATER and station BLACKOUT, for example), generate transients similar in behavior (as cold leg temperature and steam generators mixture levels, for example). Also, the sequence-of-events analysis is not always sufficient for correctly pin point the causes of the trip. (author) 11 refs., 39 figs.

  8. Willingness to pay for public services and quality of supply in the electricity area; Zahlungsbereitschaft fuer Service public und Versorgungsqualitaet im Strombereich

    Energy Technology Data Exchange (ETDEWEB)

    Leukert, K.; Telser, H.; Vaterlaus, S.; Mahler, P.

    2008-07-01

    This report for the Swiss Federal Office of Energy (SFOE) takes a look at the results of a study made on the willingness to pay for public services and quality of supply in the electricity area. First, the starting point of the study and definitions of quality of supply and security of supply are noted. The methods used in the study are presented and macro-economic aspects are reviewed. The costs of black-outs are examined and the carrying out of surveys in the electricity market is discussed. The results of surveys made in households and commercial enterprises concerning the willingness to pay for security of supply and the costs incurred when supplies fail are presented and discussed. The report is completed with a comprehensive list of references and an appendix containing the results of the various tests and surveys made.

  9. Analysis of the EU stress test results for the NPP Fessenheim and Beznau. Pt. 2. Beznau; Analyse der Ergebnisse des EU-Stresstest der Kernkraftwerke Fessenheim und Beznau. T. 2. Beznau

    Energy Technology Data Exchange (ETDEWEB)

    Brettner, Mathias [Physikerbuero Bremen (Germany); Pistner, Christoph; Kurth, Stephan [Oeko-Institut e.V. - Institut fuer Angewandte Oekologie, Darmstadt (Germany)

    2012-10-11

    As a consequence of the reactor accidents in Fukushima Daiichi the safety status of nuclear power plants was performed by national and international surveillance processes. In Germany the safety status of the NPP was testes by the reactor safety commission, an expert commission of Baden-Wuerttemberg, an expert commission of Bavaria and the EU stress test. The evaluation criteria based on national and international surveillance processes were focused on earthquakes, flooding and postulated failures of the electricity supply - station blackout and long-lasting failure of the emergency power supply. In Germany extended requirements included the electricity supply and the emergency cooling water supply. The authors identify essential safety relevant systems in the NPP Beznau, including technical systems, energy supply, plant-internal emergency measures, and discuss specific Swiss requirements. The evaluation of the EU stress test for the NPP Fessenheim covers the issues earthquake, flooding, spent fuel element pool, electricity supply, cooling water supply and identification of further safety relevant deficiencies.

  10. Analysis of the EU stress test results for the NPP Fessenheim and Beznau. Pt. 1. Fessenheim; Analyse der Ergebnisse des EU-Stresstest der Kernkraftwerke Fessenheim und Beznau. T. 1. Fessenheim

    Energy Technology Data Exchange (ETDEWEB)

    Pistner, Christoph; Kueppers, Christian; Kurth, Stephan; Mohr, Simone [Oeko-Institut e.V. - Institut fuer Angewandte Oekologie, Darmstadt (Germany); Brettner, Mathias [Physikerbuero Bremen (Germany)

    2012-10-11

    As a consequence of the reactor accidents in Fukushima Daiichi the safety status of nuclear power plants was performed by national and international surveillance processes. In Germany the safety status of the NPP was testes by the reactor safety commission, an expert commission of Baden-Wuerttemberg, an expert commission of Bavaria and the EU stress test. The evaluation criteria based on national and international surveillance processes were focused on earthquakes, flooding and postulated failures of the electricity supply - station blackout and long-lasting failure of the emergency power supply. In Germany extended requirements included the electricity supply and the emergency cooling water supply. The authors identify essential safety relevant systems in the NPP Fessenheim. The evaluation of the EU stress test for the NPP Fessenheim covers the issues earthquake, flooding, spent fuel element pool, electricity supply, cooling water supply and identification of further safety relevant deficiencies.

  11. Evaluation of an accident management strategy of emergency water injection using fire engines in a typical pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Yong; Ahn, Kwang Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Following the Fukushima accident, a special safety inspection was conducted in Korea. The inspection results show that Korean nuclear power plants have no imminent risk for expected maximum potential earthquake or coastal flooding. However long- and short-term safety improvements do need to be implemented. One of the measures to increase the mitigation capability during a prolonged station blackout (SBO) accident is installing injection flow paths to provide emergency cooling water of external sources using fire engines to the steam generators or reactor cooling systems. This paper illustrates an evaluation of the effectiveness of external cooling water injection strategies using fire trucks during a potential extended SBO accident in a 1,000 MWe pressurized water reactor. With regard to the effectiveness of external cooling water injection strategies using fire engines, the strategies are judged to be very feasible for a long-term SBO, but are not likely to be effective for a short-term SBO.

  12. Contingency-Constrained Unit Commitmentin Meshed Isolated Power Systems

    DEFF Research Database (Denmark)

    Sokoler, Leo Emil; Vinter, Peter; Bærentsen, Runi

    2015-01-01

    is kept above a predefined limit in the event of a contingency. The minimum frequency constraints are formulated using novel sufficient conditions that take into account the system inertia and the dynamics of the power generators. The proposed sufficient conditions are attractive from both a computational......This paper presents a mixed-integer linear optimization problem for unit commitment and economic dispatch of power generators in a meshed isolated power system. The optimization problem is referred to as the optimal reserve planning problem (ORPP). The ORPP guarantees that the system frequency...... and a modelling point of view. We compare the ORPP to a unit commitment problem that only considers the stationary behavior of the frequency. Simulations based on a Faroe Islands case study show that, without being overly conservative, potential blackouts and power outages can be avoided using the ORPP...

  13. Saving electricity in a hurry - update 2011

    Energy Technology Data Exchange (ETDEWEB)

    Pasquier, Sara Bryan

    2011-06-15

    As demonstrated by the March 2011 earthquake and tsunami-triggered blackouts in Japan, electricity shortfalls can happen anytime and anywhere. Countries can minimise the negative economic, social and environmental impacts of such electricity shortfalls by developing emergency energy-saving strategies before a crisis occurs. This new IEA report highlights preliminary findings and conclusions from electricity shortfalls in Japan, the United States, New Zealand, South Africa and Chile. It draws on recent analysis to: reinforce well-established guidelines on diagnosing electricity shortfalls, identifying energy-saving opportunities and selecting a package of energy-saving measures; and highlight proven practice for implementing emergency energy-saving programmes. This paper will be valuable to government, academic, private-sector and civil-society stakeholders who inform, develop and implement electricity policy in general, and emergency energy-saving programmes in particular.

  14. Profound hypoglycemia-ınduced by vaccinium corymbosum juice and laurocerasus fruit.

    Science.gov (United States)

    Aktan, Ahmet Hamdi; Ozcelik, Abdullah; Cure, Erkan; Cure, Medine Cumhur; Yuce, Suleyman

    2014-01-01

    An emergency intervention was performed in a 75-year-old male patient with hypoglycemic attack and blackout. Although he was diagnosed with prediabetes before 2 years, he did not take any anti-diabetic drug or follow dietary advice. He drank Vaccinium corymbosum L (VC) juice daily with a belief that it increases sexual potency. Before the development of hypoglycemia, the patient had consumed about 500 ml VC juice in addition to eating 200-300 gram of Laurocerasus officinalis (LO) fruit. The measured plasma glucose (PG) level during loss of consciousness was 30 mg/dl. The profound hypoglycemia may be an unexpected side effect of an interaction between the chemical compositions of the two plants, occurred as a result of LO fruit intake that may have a strong PG-lowering effect or related to excessive intake of VC juice. Both plants may be considered in the alternative treatment of diabetes.

  15. Fukushima accident study using MELCOR

    Institute of Scientific and Technical Information of China (English)

    Randall O Gauntt

    2013-01-01

    The accidents at the Fukushima Daiichi nuclear power station stunned the world as the sequences played out over severals days and videos of hydrogen explosions were televised as they took place.The accidents all resulted in severe damage to the reactor cores and releases of radioactivity to the environment despite heroic measures had taken by the operating personnel.The following paper provides some background into the development of these accidents and their root causes,chief among them,the prolonged station blackout conditions that isolated the reactors from their ultimate heat sink — the ocean.The interpretations given in this paper are summarized from a recently completed report funded by the United States Department of Energy (USDOE).

  16. Real-Time Stability Assessment based on Synchrophasors

    DEFF Research Database (Denmark)

    Jóhannsson, Hjörtur; Garcia-Valle, Rodrigo; Weckesser, Johannes Tilman Gabriel;

    2011-01-01

    eventually cause in very sharp decline in system voltages at intermediate locations between the two groups as the angular separation approaches 180◦. In order to receive an early warning for the occurrence of such type of blackouts, the boundaries of the system generators aperiodic small-signal stability...... are suggested to be monitored. For that purpose, method for real-time assessment of aperiodic small-signal rotor angle stability is presented. The approach is based on an element-wise assessment of individual synchronous machines where the aim is to determine the maximum steady state power that each synchronous...... generator can inject into the system. The limits for maximum injectable power represent the boundary for aperiodic small signal stability. The concept of the proposed method is tested on two different systems. The results show that the method is capable of accurately detecting when a given machine crosses...

  17. Analysis of SBO ATWS for Maanshan PWR

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Che-Hao; Chen, Shao-Wen [National Tsing Hua Univ., Hsinchu, Taiwan (China). Inst. of Nuclear Engineering and Science; Wang, Jong-Rong; Shih, Chunkuan [National Tsing Hua Univ., Hsinchu, Taiwan (China). Inst. of Nuclear Engineering and Science; Nuclear and New Energy Education and Research Foundation, Hsinchu, Taiwan (China); Lin, Hao-Tzu [Atomic Energy Council, Taoyuan, Taiwan (China). Inst. of Nuclear Energy Research

    2015-11-15

    Station blackout anticipated transient without scram (SBO ATWS) is considered as loss of off-site and on-site power but no credit for automatic reactor trip. SBO ATWS causes reactor coolant pump (RCP) trip, loss of all main feedwater pumps and turbine trip, then the reactor coolant system (RCS) pressure rises rapidly due to loss of heat removal paths. The ASME Code Level C service limit criteria of 22.06 MPa (3200 psig) is assumed to be an unacceptable plant condition in SECY-83-293. The simulation is performed by TRACE which is a thermal-hydraulic code developed by U.S. NRC. Three different AFW flows are modeled to ensure the pressures will not be beyond the criteria. RCP seal-leakage is concerned as a SBLOCA due to loss of RCP seal-cooling. Four possible leakage flows are modeled to examine the reactor core water level and temperature variation.

  18. Our energies have a future. A future without CO{sub 2}. Areva in 2005; Nos energies ont de l'avenir. Un avenir sans CO{sub 2}. Areva en 2005

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This document is the sustainable development and 2005 annual report altogether of Areva group. It presents first the challenges of energy for economical development, the climate change threat and the sustainability of nuclear power in particular with respect to radioactive wastes management and power blackouts. Then follows a presentation of Areva's 10 commitments for sustainable development (governance and continuous improvement, financial performance, innovation, customer satisfaction, commitment to employees, risk management and prevention, environmental protection, dialogue and consensus building, community involvement). The annual report presents: the 2005 highlights, Areva around the world, key data, corporate governance, organisation of the group, share information and shareholder relations, business review (front end division, reactors and services division, back end division, transmission and distribution division), financial report and glossary. (J.S.)

  19. Design of a Sustainable and Efficient Transportation Station (SETS Based on Renewable Sources and Efficient Electric Drives

    Directory of Open Access Journals (Sweden)

    Myungchin Kim

    2016-12-01

    Full Text Available The need for reduction in power consumption for public facilities has increased after the occurrences of multiple blackout events. In an effort to enable the development of green and smart social infrastructure, this paper introduces a design for a sustainable and efficient transportation system (SETS. For this design, renewable power sources and efficient electric drives are considered to be crucial technologies. Considering the subway station as an illustrative example, a power system design that uses wind and solar energy as major power sources is studied. The adjustable speed electric drive system that uses synchronous reluctance machines for ventilation systems contributes to increasing the overall power consumption efficiency. The effectiveness of the proposed SETS system is verified through a set of various field measurement data and simulation results. While the verification results demonstrate that operation of SETS is enabled by effective integration of renewable sources and efficient ventilation systems, future research directions have also been identified.

  20. Modeling the recovery phase of extreme geomagnetic storms

    CERN Document Server

    Cid, C; Saiz, E; Cerrato, Y; Aguado, J; Guerrero, A

    2014-01-01

    The recovery phase of the largest storms ever recorded has been studied. These events provide an extraordinary opportunity for two goals: (1) to validate the hyperbolic model by Aguado et al. [2010] for the recovery phase after disturbances as severe as the Carrington event, or that related to the Hydro-Quebec blackout in March 1989, and (2) to check whether the linear relationship between the recovery time and the intensity of the storm still complies. Our results reveal the high accuracy of the hyperbolic decay function to reproduce the recovery phase of the magnetosphere after an extreme storm. Moreover, the characteristic time that takes the magnetosphere to recover depends in an exponential way on the intensity of the storm, as indicated by the relationship between the two parameters involved in the hyperbolic decay. This exponential function can be approached by a linear function when the severity of the storm diminishes.

  1. Development of accident management technology and computer codes -A study for nuclear safety improvement-

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Kyu; Jae, Moo Sung; Jo, Young Gyun; Park, Rae Jun; Kim, Jae Hwan; Ha, Jae Ju; Kang, Dae Il; Choi, Sun Young; Kim, Si Hwan [Korea Atomic Energy Res. Inst., Taejon (Korea, Republic of)

    1994-07-01

    We have surveyed new technologies and research results for the accident management of nuclear power plants. And, based on the concept of using the existing plant capabilities for accident management, both in-vessel and ex-vessel strategies were identified and analyzed. When assessing accident management strategies, their effectiveness, adverse effects, and their feasibility must be considered. We have developed a framework for assessing the strategies with these factors in mind. We have applied the developed framework to assessing the strategies, including the likelihood that the operator correctly diagnoses the situation and successfully implements the strategies. Finally, the cavity flooding strategy was assessed by applying it to the station blackout sequence, which have been identified as one of the major contributors to risk at the reference plant. The thermohydraulic analyses with sensitivity calculations have been performed using MAAP 4 computer code. (Author).

  2. Combining Agile and Traditional: Customer Communication in Distributed Environment

    Science.gov (United States)

    Korkala, Mikko; Pikkarainen, Minna; Conboy, Kieran

    Distributed development is a radically increasing phenomenon in modern software development environments. At the same time, traditional and agile methodologies and combinations of those are being used in the industry. Agile approaches place a large emphasis on customer communication. However, existing knowledge on customer communication in distributed agile development seems to be lacking. In order to shed light on this topic and provide practical guidelines for companies in distributed agile environments, a qualitative case study was conducted in a large globally distributed software company. The key finding was that it might be difficult for an agile organization to get relevant information from a traditional type of customer organization, even though the customer communication was indicated to be active and utilized via multiple different communication media. Several challenges discussed in this paper referred to "information blackout" indicating the importance of an environment fostering meaningful communication. In order to evaluate if this environment can be created a set of guidelines is proposed.

  3. Total loss of AC power analysis for EPR reactor

    Energy Technology Data Exchange (ETDEWEB)

    Darnowski, Piotr, E-mail: piotr.darnowski@itc.pw.edu.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Skrzypek, Eleonora, E-mail: eleonora.skrzypek@ncbj.gov.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); National Centre for Nuclear Research (NCBJ), A. Sołtana 7, 05-400 Otwock-Świerk (Poland); Mazgaj, Piotr, E-mail: piotr.mazgaj@itc.pw.edu.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Świrski, Konrad [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Gandrille, Pascal [AREVA NP SAS, Tour AREVA, 1 place Jean Millier, 92084 Paris La Défense (France)

    2015-08-15

    Highlights: • Total loss of AC power (Station Blackout) was simulated for the EPR reactor model. • In-vessel phase of the accident is under consideration. • Comparison of MELCOR and MAAP results is presented. • MELCOR and MAAP results are comparable. - Abstract: In this paper the results of severe accident simulations for the EPR reactor in the case of loss of offsite power combined with total failure of all diesel generators (total loss of AC power) are presented. Calculations were performed with MELCOR 2.1 computer code for in-vessel phase of the accident. In this scenario, the unavailability of all offsite and onsite power sources and the lack of cooling leads directly to core degradation, material relocation to the lower plenum and rupture of the reactor pressure vessel. MELCOR results were compared qualitatively and quantitatively with MAAP4 code results and show a good agreement.

  4. Ising model for distribution networks

    CERN Document Server

    Hooyberghs, H; Giuraniuc, C; Van Schaeybroeck, B; Indekeu, J O

    2012-01-01

    An elementary Ising spin model is proposed for demonstrating cascading failures (break-downs, blackouts, collapses, avalanches, ...) that can occur in realistic networks for distribution and delivery by suppliers to consumers. A ferromagnetic Hamiltonian with quenched random fields results from policies that maximize the gap between demand and delivery. Such policies can arise in a competitive market where firms artificially create new demand, or in a solidary environment where too high a demand cannot reasonably be met. Network failure in the context of a policy of solidarity is possible when an initially active state becomes metastable and decays to a stable inactive state. We explore the characteristics of the demand and delivery, as well as the topological properties, which make the distribution network susceptible of failure. An effective temperature is defined, which governs the strength of the activity fluctuations which can induce a collapse. Numerical results, obtained by Monte Carlo simulations of t...

  5. The USGS Geomagnetism Program and its role in Space-Weather Monitoring

    Science.gov (United States)

    Love, Jeffrey J.; Finn, Carol A.

    2011-01-01

    Magnetic storms result from the dynamic interaction of the solar wind with the coupled magnetospheric-ionospheric system. Large storms represent a potential hazard for the activities and infrastructure of a modern, technologically based society [Baker et al., 2008]; they can cause the loss of radio communications, reduce the accuracy of global positioning systems, damage satellite electronics and affect satellite operations, increase pipeline corrosion, and induce voltage surges in electric power grids, causing blackouts. So while space weather starts with the Sun and is driven by the solar wind, it is on, or just above, the surface of the Earth that the practical effects of space weather are realized. Therefore, ground-based sensor networks, including magnetic observatories [Love, 2008], play an important role in space weather monitoring.

  6. The USGS geomagnetism program and its role in space weather monitoring

    Science.gov (United States)

    Love, J.J.; Finn, C.A.

    2011-01-01

    Magnetic storms result from the dynamic interaction of the solar wind with the coupled magnetospheric-ionospheric system. Large storms represent a potential hazard for the activities and infrastructure of a modern, technologically based society [Baker et al., 2008]; they can cause the loss of radio communications, reduce the accuracy of global positioning systems, damage satellite electronics and affect satellite operations, increase pipeline corrosion, and induce voltage surges in electric power grids, causing blackouts. So while space weather starts with the Sun and is driven by the solar wind, it is on, or just above, the surface of the Earth that the practical effects of space weather are realized. Therefore, ground-based sensor networks, including magnetic observatories [Love, 2008], play an important role in space weather monitoring. Copyright 2011 by the American Geophysical Union.

  7. Probabilistic risk assessment course documentation. Volume 1: PRA fundamentals

    Energy Technology Data Exchange (ETDEWEB)

    Breeding, R J; Leahy, T J; Young, J

    1985-08-01

    The full range of PRA topics is presented, with a special emphasis on systems analysis and PRA applications. Systems analysis topics include system modeling such as fault tree and event tree construction, failure rate data, and human Reliability. The discussion of PRA applications is centered on past and present PRA based programs, such as WASH-1400 and the Interim Reliability Evaluation Program, as well as on some of the potential future applications of PRA. The relationship of PRA to generic safety issues such as station blackout and Anticipated Transient Without Scram (ATWS) is also discussed. In addition to system modeling, the major PRA tasks of accident process analysis, and consequence analysis are presented. An explanation of the results of these activities, and the techniques by which these results are derived, forms the basis for a discussion of these topics. An additional topic which is presented in this course is the topic of PRA management, organization, and evaluation. 84 figs., 41 tabs.

  8. Importance Sampling Based Decision Trees for Security Assessment and the Corresponding Preventive Control Schemes: the Danish Case Study

    DEFF Research Database (Denmark)

    Liu, Leo; Rather, Zakir Hussain; Chen, Zhe

    2013-01-01

    and adopts a methodology of importance sampling to maximize the information contained in the database so as to increase the accuracy of DT. Further, this paper also studies the effectiveness of DT by implementing its corresponding preventive control schemes. These approaches are tested on the detailed model......Decision Trees (DT) based security assessment helps Power System Operators (PSO) by providing them with the most significant system attributes and guiding them in implementing the corresponding emergency control actions to prevent system insecurity and blackouts. DT is obtained offline from time......-domain simulation and the process of data mining, which is then implemented online as guidelines for preventive control schemes. An algorithm named Classification and Regression Trees (CART) is used to train the DT and key to this approach lies on the accuracy of DT. This paper proposes contingency oriented DT...

  9. Node seniority ranking

    CERN Document Server

    Fioriti, Vincenzo

    2014-01-01

    Recent advances in graph theory suggest that is possible to identify the oldest nodes of a network using only the graph topology. Here we report on applications to heterogeneous real world networks. To this end, and in order to gain new insights, we propose the theoretical framework of the Estrada communicability. We apply it to two technological networks (an underground, the diffusion of a software worm in a LAN) and to a third network representing a cholera outbreak. In spite of errors introduced in the adjacency matrix of their graphs, the identification of the oldest nodes is feasible, within a small margin of error, and extremely simple. Utilizations include the search of the initial disease-spreader (patient zero problem), rumors in social networks, malware in computer networks, triggering events in blackouts, oldest urban sites recognition.

  10. Network science quantification of resilience demonstrated on the Indian Railways Network

    CERN Document Server

    Bhatia, Udit; Kodra, Evan; Ganguly, Auroop R

    2015-01-01

    The structure, interdependence, and fragility of systems ranging from power grids and transportation to ecology, climate, biology and even human communities and the Internet, have been examined through network science. While the response to perturbations has been quantified, recovery strategies for perturbed networks have usually been either discussed conceptually or through anecdotal case studies. Here we develop a network science-based quantitative methods framework for measuring, comparing and interpreting hazard responses and as well as recovery strategies. The framework, motivated by the recently proposed temporal resilience paradigm, is demonstrated with the Indian Railways Network. The methods are demonstrated through the resilience of the network to natural or human-induced hazards and electric grid failure. Simulations inspired by the 2004 Indian Ocean Tsunami and the 2012 North Indian blackout as well as a cyber-physical attack scenario. Multiple metrics are used to generate various recovery strateg...

  11. Steady-state analysis of the effect of reactive generation limits in voltage stability

    Energy Technology Data Exchange (ETDEWEB)

    Echavarren, F.M.; Lobato, E.; Rouco, L. [School of Engineering of Universidad Pontificia Comillas, C/Alberto Aguilera, 23, 28015 Madrid (Spain)

    2009-09-15

    Voltage collapse phenomena are highly affected by reactive power generation limits. Saturation of the reactive power generation limits of a unit may result in a deterioration of the voltage stability. However, in some cases when the power network is operating close to the voltage collapse point, the reactive power generation saturation of a unit can change the system voltages immediately from stable to unstable; thus, a dynamic voltage collapse leading to blackout may follow. This paper presents a steady-state analysis of the immediate instability caused by reactive power generation saturation phenomena. For this purpose, the paper proposes a novel index that evaluates ''when'' and ''why'' a reactive power generation saturation will only result in a deterioration of the system voltage stability or, on the contrary, it will make the system voltages immediately unstable. (author)

  12. Effect of Wind Intermittency on the Electric Grid: Mitigating the Risk of Energy Deficits

    CERN Document Server

    George, Sam O; Nguyen, Scott V

    2010-01-01

    Successful implementation of California's Renewable Portfolio Standard (RPS) mandating 33 percent renewable energy generation by 2020 requires inclusion of a robust strategy to mitigate increased risk of energy deficits (blackouts) due to short time-scale (sub 1 hour) intermittencies in renewable energy sources. Of these RPS sources, wind energy has the fastest growth rate--over 25% year-over-year. If these growth trends continue, wind energy could make up 15 percent of California's energy portfolio by 2016 (wRPS15). However, the hour-to-hour variations in wind energy (speed) will create large hourly energy deficits that require installation of other, more predictable, compensation generation capacity and infrastructure. Compensating for the energy deficits of wRPS15 could potentially cost tens of billions in additional dollar-expenditure for fossil and / or nuclear generation capacity. There is a real possibility that carbon dioxide and other greenhouse gas (GHG) emission reductions will miss the California ...

  13. What organizations did (and didn't) do: Three factors that shaped conservation responses to California's 2001 'crisis'

    Energy Technology Data Exchange (ETDEWEB)

    Janda, Kathryn; Payne, Christopher; Kunkle, Rick; Lutzenhiser, Loren

    2002-08-18

    Beginning in the summer of 2000, California experienced energy supply problems, sharp increases in electricity and natural gas prices, and isolated blackouts. In response, California's state government implemented an unprecedented energy conservation effort to mitigate projected electricity supply shortages during the summer of 2001. Ultimately, significant electricity demand and consumption reductions were achieved. This paper considers the response of commercial and institutional organizations to the California energy situation and offers a description of three factors that shaped these responses: (1) concern about energy problems; (2) operational conditions; and (3) institutional capacity for action. A matrix of possible combinations of concern, conditions, and capacity offers a heuristic for use in exploring how to best tailor and target policy interventions to the circumstances of particular subgroups of organizations.

  14. The Impact of the Topology on Cascading Failures in Electric Power Grids

    CERN Document Server

    Koç, Yakup; Van Mieghem, Piet; Kooij, Robert E; Brazier, Frances M T

    2014-01-01

    Cascading failures are one of the main reasons for blackouts in power transmission grids. The topology of a power grid, together with its operative state determine, for the most part, the robustness of the power grid against cascading failures. Secure electrical power supply requires, together with careful operation, a robust design of the electrical power grid topology. This paper investigates the impact of a power grid topology on its robustness against cascading failures. Currently, the impact of the topology on a grid robustness is mainly assessed by using purely topological approaches that fail to capture the essence of electric power flow. This paper proposes a metric, the effective graph resistance, that relates the topology of a power grid to its robustness against cascading failures by deliberate attacks, while also taking the fundamental characteristics of the electric power grid into account such as power flow allocation according to Kirchoff Laws. Experimental verification shows that the proposed ...

  15. The impact of the topology on cascading failures in a power grid model

    Science.gov (United States)

    Koç, Yakup; Warnier, Martijn; Mieghem, Piet Van; Kooij, Robert E.; Brazier, Frances M. T.

    2014-05-01

    Cascading failures are one of the main reasons for large scale blackouts in power transmission grids. Secure electrical power supply requires, together with careful operation, a robust design of the electrical power grid topology. Currently, the impact of the topology on grid robustness is mainly assessed by purely topological approaches, that fail to capture the essence of electric power flow. This paper proposes a metric, the effective graph resistance, to relate the topology of a power grid to its robustness against cascading failures by deliberate attacks, while also taking the fundamental characteristics of the electric power grid into account such as power flow allocation according to Kirchhoff laws. Experimental verification on synthetic power systems shows that the proposed metric reflects the grid robustness accurately. The proposed metric is used to optimize a grid topology for a higher level of robustness. To demonstrate its applicability, the metric is applied on the IEEE 118 bus power system to improve its robustness against cascading failures.

  16. Increase of Power System Survivability with the Decision Support Tool CRIPS Based on Network Planning and Simulation Program PSS®SINCAL

    Science.gov (United States)

    Schwaegerl, Christine; Seifert, Olaf; Buschmann, Robert; Dellwing, Hermann; Geretshuber, Stefan; Leick, Claus

    The increased interconnection and automation of critical infrastructures enlarges the complexity of the dependency structures and - as consequence - the danger of cascading effects, e.g. causing area-wide blackouts in power supply networks that are currently after deregulation operated closer to their limits. New tools or an intelligent combination of existing approaches are required to increase the survivability of critical infrastructures. Within the IRRIIS project the expert system CRIPS was developed based on network simulations realised with PSS®SINCAL, an established tool to support the analysis and planning of electrical power, gas, water or heat networks. CRIPS assesses the current situation in power supply networks analysing the simulation results of the physical network behaviour and recommends corresponding decisions.

  17. Model and Algorithm for the Optimal Controlled Partitioning of Power Systems

    Institute of Scientific and Technical Information of China (English)

    LIN Jikeng; LI Shengwen; WU Peng; WANG Xudong; SHAO Guanghui; XU Xingwei; MA Xin

    2012-01-01

    In China, with the development of projects such as "electricity transmission from the West to the East" and "power exchange between the South and the North", and with the UHV project being put into operation, a nation-wide interconnection system has been formed. For such big interconnection system, local faults or disturbances might lead to large-scale power blackouts and even system collapses, which will cause direct and indirect losses comparable to a big natural disaster. By taking proper and reasonable controlled partition measures, the risk of long-period and large-area power failure and even system collapse will be greatly reduced. However, with the system size increasing, the number of partition interface will grow geometrically, and therefore, it is a great challenge for a nation-wide interconnection system to achieve the optimal partition surface.

  18. An important year for Swiss Electricity Politics - President's speech at the shareholder's meeting of the Swiss Association of Electricity Enterprises; Strompolitisch relevantes Jahr

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, R

    2004-07-01

    This article presents the speech made by Rudolf Steiner, president of the Swiss Association of Electricity Enterprises, in Bad Ragaz in September 2004. Steiner comments on 2004 as being an important year with respect to energy politics in Switzerland. A public vote turned down the idea of opting out of nuclear energy, the Federal Court decided that the Restricted Trade Practices act was also applicable to the Swiss electricity supply industry and the EU parliament passed guidelines on the opening of the European power market. The effects of large-scale blackouts in America and Europe on the public's perception of secure supplies are commented on. The importance of the Association as a provider of services for its members and as a partner for the government is stressed.

  19. The integrated resource planning of the energy sector as a basis to water management in urban areas

    Directory of Open Access Journals (Sweden)

    Gilberto de Martino Jannuzzi

    2008-12-01

    Full Text Available The Water Resources Planning in use doesn´t diverges substantially from the Traditional Energy Planning. With the energy crisis occurred at Brazil in 2001 the blackout possibility shows that the impact on the society might happen at any time. The same occurs to the water because of its scarcity. The Integrated Resource Planning (IRP was diffused as a way of fully managing a resource by the supply and demand sizes and can be considerated a viable option for the conventional planning. This composition is meant to do a study of the specific bibliography about the energy IRP and the Water Resource Management. Utilizing conceptions of the energy area, Water Integrated Resource Planning has been created to be used at the public utilities. The Water Integrated Resource Planning conducts the Water Integrated Management through this resource saving, joining this to a different tax and increasing the supply with alternative options such as the wastewater and the rainwater use.

  20. Security assessment for intentional island operation in modern power system

    DEFF Research Database (Denmark)

    Chen, Yu; Xu, Zhao; Østergaard, Jacob

    2011-01-01

    operator can clearly know if it is suitable to conduct island operation at one specific moment. Besides, in order to improve the computation efficiency, the Artificial Neural Network (ANN) is applied for fast ISR formation. Thus, online application of ISR based islanding security assessment could......There has been a high penetration level of Distributed Generations (DGs) in distribution systems in Denmark. Even more DGs are expected to be installed in the coming years. With that, to utilize them in maintaining the security of power supply is of great concern for Danish utilities. During...... the emergency in the power system, some distribution networks may be intentionally separated from the main grid to avoid complete system collapse. If DGs in those networks could continuously run instead of immediately being shut down, the blackout could be avoided and the reliability of supply could...

  1. Electromagnetic pulse research on electric power systems: Program summary and recommendations. Power Systems Technology Program

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P.R.; McConnell, B.W.; Van Dyke, J.W. [Oak Ridge National Lab., TN (United States); Tesche, F.M. [Tesche (F.M.), Dallas, TX (United States); Vance, E.F. [Vance (E.F.), Fort Worth, TX (United States)

    1993-01-01

    A single nuclear detonation several hundred kilometers above the central United States will subject much of the nation to a high-altitude electromagnetic pulse (BENT). This pulse consists of an intense steep-front, short-duration transient electromagnetic field, followed by a geomagnetic disturbance with tens of seconds duration. This latter environment is referred to as the magnetohydrodynamic electromagnetic pulse (NMENT). Both the early-time transient and the geomagnetic disturbance could impact the operation of the nation`s power systems. Since 1983, the US Department of Energy has been actively pursuing a research program to assess the potential impacts of one or more BENT events on the nation`s electric energy supply. This report summarizes the results of that program and provides recommendations for enhancing power system reliability under HENT conditions. A nominal HENP environment suitable for assessing geographically large systems was developed during the program and is briefly described in this report. This environment was used to provide a realistic indication of BEMP impacts on electric power systems. It was found that a single high-altitude burst, which could significantly disturb the geomagnetic field, may cause the interconnected power network to break up into utility islands with massive power failures in some areas. However, permanent damage would be isolated, and restoration should be possible within a few hours. Multiple bursts would likely increase the blackout areas, component failures, and restoration time. However, a long-term blackout of many months is unlikely because major power system components, such as transformers, are not likely to be damaged by the nominal HEND environment. Moreover, power system reliability, under both HENT and normal operating conditions, can be enhanced by simple, and often low cost, modifications to current utility practices.

  2. Electromagnetic pulse research on electric power systems: Program summary and recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P.R.; McConnell, B.W.; Van Dyke, J.W. (Oak Ridge National Lab., TN (United States)); Tesche, F.M. (Tesche (F.M.), Dallas, TX (United States)); Vance, E.F. (Vance (E.F.), Fort Worth, TX (United States))

    1993-01-01

    A single nuclear detonation several hundred kilometers above the central United States will subject much of the nation to a high-altitude electromagnetic pulse (BENT). This pulse consists of an intense steep-front, short-duration transient electromagnetic field, followed by a geomagnetic disturbance with tens of seconds duration. This latter environment is referred to as the magnetohydrodynamic electromagnetic pulse (NMENT). Both the early-time transient and the geomagnetic disturbance could impact the operation of the nation's power systems. Since 1983, the US Department of Energy has been actively pursuing a research program to assess the potential impacts of one or more BENT events on the nation's electric energy supply. This report summarizes the results of that program and provides recommendations for enhancing power system reliability under HENT conditions. A nominal HENP environment suitable for assessing geographically large systems was developed during the program and is briefly described in this report. This environment was used to provide a realistic indication of BEMP impacts on electric power systems. It was found that a single high-altitude burst, which could significantly disturb the geomagnetic field, may cause the interconnected power network to break up into utility islands with massive power failures in some areas. However, permanent damage would be isolated, and restoration should be possible within a few hours. Multiple bursts would likely increase the blackout areas, component failures, and restoration time. However, a long-term blackout of many months is unlikely because major power system components, such as transformers, are not likely to be damaged by the nominal HEND environment. Moreover, power system reliability, under both HENT and normal operating conditions, can be enhanced by simple, and often low cost, modifications to current utility practices.

  3. Post shut-down decay heat removal from nuclear reactor core by natural convection loops in sodium pool

    Energy Technology Data Exchange (ETDEWEB)

    Rajamani, A. [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Sundararajan, T., E-mail: tsundar@iitm.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Prasad, B.V.S.S.S. [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Parthasarathy, U.; Velusamy, K. [Nuclear Engineering Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

    2016-05-15

    Highlights: • Transient simulations are performed for a worst case scenario of station black-out. • Inter-wrapper flow between various sub-assemblies reduces peak core temperature. • Various natural convection paths limits fuel clad temperatures below critical level. - Abstract: The 500 MWe Indian pool type Prototype Fast Breeder Reactor (PFBR) has a passive core cooling system, known as the Safety Grade Decay Heat Removal System (SGDHRS) which aids to remove decay heat after shut down phase. Immediately after reactor shut down the fission products in the core continue to generate heat due to beta decay which exponentially decreases with time. In the event of a complete station blackout, the coolant pump system may not be available and the safety grade decay heat removal system transports the decay heat from the core and dissipates it safely to the atmosphere. Apart from SGDHRS, various natural convection loops in the sodium pool carry the heat away from the core and deposit it temporarily in the sodium pool. The buoyancy driven flow through the small inter-wrapper gaps (known as inter-wrapper flow) between fuel subassemblies plays an important role in carrying the decay heat from the sub-assemblies to the hot sodium pool, immediately after reactor shut down. This paper presents the transient prediction of flow and temperature evolution in the reactor subassemblies and the sodium pool, coupled with the safety grade decay heat removal system. It is shown that with a properly sized decay heat exchanger based on liquid sodium and air chimney stacks, the post shutdown decay heat can be safely dissipated to atmospheric air passively.

  4. The propagation characteristics of electromagnetic waves through plasma in the near-field region of low-frequency loop antenna

    Energy Technology Data Exchange (ETDEWEB)

    Liu, DongLin, E-mail: donglinliu@stu.xidian.edu.cn; Li, XiaoPing; Xie, Kai; Liu, ZhiWei [School of Aerospace Science and Technology, Xidian University, Xi' an 710071 (China)

    2015-10-15

    A high-speed vehicle flying through the atmosphere between 100 and 20 km may suffer from a “communication blackout.” In this paper, a low frequency system with an on-board loop antenna to receive signals is presented as a potential blackout mitigation method. Because the plasma sheath is in the near-field region of the loop antenna, the traditional scattering matrix method that is developed for the far-field region may overestimate the electromagnetic (EM) wave's attenuation. To estimate the EM wave's attenuation in the near-field region, EM interference (EMI) shielding theory is introduced. Experiments are conducted, and the results verify the EMI shielding theory's effectiveness. Simulations are also conducted with different plasma parameters, and the results obtained show that the EM wave's attenuation in the near-field region is far below than that in the far-field region. The EM wave's attenuation increases with the increase in electron density and decreases with the increase in collision frequency. The higher the frequency, the larger is the EM wave's attenuation. During the entire re-entry phase of a RAM-C module, the EM wave's attenuations are below 10 dB for EM waves with a frequency of 1 MHz and below 1 dB for EM waves with a frequency of 100 kHz. Therefore, the low frequency systems (e.g., Loran-C) may provide a way to transmit some key information to high-speed vehicles even during the communication “blackout” period.

  5. Attenuation of low-frequency electromagnetic wave in the thin sheath enveloping a high-speed vehicle upon re-entry

    Science.gov (United States)

    Liu, DongLin; Li, XiaoPing; Liu, YanMing; Xie, Kai; Bai, BoWen

    2017-02-01

    Low-frequency (LF) electromagnetic (EM) waves are suggested as potentially solving "radio blackout" caused by a plasma sheath enveloping a high-speed vehicle on re-entry. However, the traditional plasma absorption theory neglects the fact that the plasma sheath is electrically small compared to LF EM wavelengths. To understand clearly the attenuation of such waves through the plasma sheath, different attenuation mechanisms for the electric field (SE) and magnetic field (SH) were studied using the equivalent circuit approach. Analytical expressions were derived by modeling the plasma sheath as a spherical shell, and numerical simulations were performed to validate the effectiveness of the expressions. SE and SH are calculated for various plasma parameter settings; the EM wave attenuations obtained from plasma absorption theory are used for comparison. Results show that, instead of SE and SH being equal in the plasma absorption theory, SE and SH are no longer the same for electrically small sizes. Whereas |SH| is close to that from plasma absorption theory, |SE| is much higher. Further analysis shows that |SH| is a function of the ratio of electron density (ne) and collision frequency (ve) and increases with increasing ne/ve. Numerical simulations with radio-attenuation-measurement-C-like vehicle's plasma sheath parameters are performed and the results show that the magnetic field attenuation in the front part of the vehicle is much lower than in the rear. So it is suggested to place the magnetic loop antenna in the very front part of the vehicle. Finally, SH at different frequencies are calculated using plasma sheath parameter values simulating the re-entry phase of a radio-attenuation measurement-C vehicle and results show that such a vehicle might overcome radio blackout during the entire re-entry phase if systems operating below 3 MHz and above the L-band are combined with a lower-frequency system working below Earth's ionosphere and a higher-frequency system

  6. Use of VIIRS DNB Data to Monitor Power Outages and Restoration for Significant Weather Events

    Science.gov (United States)

    Jedlovec, Gary; Molthan, Andrew

    2008-01-01

    NASA fs Short-term Prediction Research and Transition (SPoRT) project operates from NASA's Marshall Space Flight Center in Huntsville, Alabama. The team provides unique satellite data to the National Weather Service (NWS) and other agencies and organizations for weather analysis. While much of its work is focused on improving short-term weather forecasting, the SPoRT team supported damage assessment and response to Hurricane Superstorm Sandy by providing imagery that highlighted regions without power. The team used data from the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite. The VIIRS low-light sensor, known as the day-night-band (DNB), can detect nighttime light from wildfires, urban and rural communities, and other human activity which emits light. It can also detect moonlight reflected from clouds and surface features. Using real time VIIRS data collected by our collaborative partner at the Space Science and Engineering Center of the University of Wisconsin, the SPoRT team created composite imagery to help detect power outages and restoration. This blackout imagery allowed emergency response teams from a variety of agencies to better plan and marshal resources for recovery efforts. The blackout product identified large-scale outages, offering a comprehensive perspective beyond a patchwork GIS mapping of outages that utility companies provide based on customer complaints. To support the relief efforts, the team provided its imagery to the USGS data portal, which the Federal Emergency Management Agency (FEMA) and other agencies used in their relief efforts. The team fs product helped FEMA, the U.S. Army Corps of Engineers, and U.S. Army monitor regions without power as part of their disaster response activities. Disaster responders used the images to identify possible outages and effectively distribute relief resources. An enhanced product is being developed and integrated into a web

  7. Optimal operation of hybrid-SITs under a SBO accident

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, In Seop, E-mail: inseopjeon@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Heo, Sun, E-mail: sunnysunny@khnp.co.kr [Central Research Institute, Korea Hydro & Nuclear Power Co., 70 Yuseong-daero 1312 beon-gil, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Kang, Hyun Gook, E-mail: hyungook@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2016-02-15

    Highlights: • Operation strategy of hybrid-SIT (H-SIT) in station blackout (SBO) is developed. • There are five main factors which have to be carefully treated in the development of the operation strategy. • Optimal value of each main factor is investigated analytically and then through thermal-hydraulic analysis using computer code. • The optimum operation strategy is suggested based on the optimal value of the main factors. - Abstract: A hybrid safety injection tank (H-SIT) is designed to enhance the capability of pressurized water reactors against high-pressure accidents which might be caused by the combined accidents accompanied by station blackout (SBO), and is suggested as a useful alternative to electricity-driven motor injection pumps. The main purpose of the H-SIT is to provide coolant to the core so that core safety can be maintained for a longer period. As H-SITs have a limited inventory, their efficient use in cooling down the core is paramount to maximize the available time for long-term cooling component restoration. Therefore, an optimum operation strategy must be developed to support the operators for the most efficient H-SIT use. In this study, the main factors which have to be carefully treated in the development of an operation strategy are first identified. Then the optimal value of each main factor is investigated analytically, a process useful to get the basis of the global optimum points. Based on these analytical optimum points, a thermal-hydraulic analysis using MARS code is performed to get more accurate values and to verify the results of the analytical study. The available time for long-term cooling component restoration is also estimated. Finally, an integrated optimum operation strategy for H-SITs in SBO is suggested.

  8. Final Report: Assessment of Combined Heat and Power Premium Power Applications in California

    Energy Technology Data Exchange (ETDEWEB)

    Norwood, Zack; Lipman, Tim; Marnay, Chris; Kammen, Dan

    2008-09-30

    This report analyzes the current economic and environmental performance of combined heat and power (CHP) systems in power interruption intolerant commercial facilities. Through a series of three case studies, key trade-offs are analyzed with regard to the provision of black-out ridethrough capability with the CHP systems and the resutling ability to avoid the need for at least some diesel backup generator capacity located at the case study sites. Each of the selected sites currently have a CHP or combined heating, cooling, and power (CCHP) system in addition to diesel backup generators. In all cases the CHP/CCHP system have a small fraction of the electrical capacity of the diesel generators. Although none of the selected sites currently have the ability to run the CHP systems as emergency backup power, all could be retrofitted to provide this blackout ride-through capability, and new CHP systems can be installed with this capability. The following three sites/systems were used for this analysis: (1) Sierra Nevada Brewery - Using 1MW of installed Molten Carbonate Fuel Cells operating on a combination of digestor gas (from the beer brewing process) and natural gas, this facility can produce electricty and heat for the brewery and attached bottling plant. The major thermal load on-site is to keep the brewing tanks at appropriate temperatures. (2) NetApp Data Center - Using 1.125 MW of Hess Microgen natural gas fired reciprocating engine-generators, with exhaust gas and jacket water heat recovery attached to over 300 tons of of adsorption chillers, this combined cooling and power system provides electricity and cooling to a data center with a 1,200 kW peak electrical load. (3) Kaiser Permanente Hayward Hospital - With 180kW of Tecogen natural gas fired reciprocating engine-generators this CHP system generates steam for space heating, and hot water for a city hospital. For all sites, similar assumptions are made about the economic and technological constraints of the

  9. Human Factors for Situation Assessment in Grid Operations

    Energy Technology Data Exchange (ETDEWEB)

    Guttromson, Ross T.; Schur, Anne; Greitzer, Frank L.; Paget, Mia L.

    2007-08-08

    Executive Summary Despite advances in technology, power system operators must assimilate overwhelming amounts of data to keep the grid operating. Analyses of recent blackouts have clearly demonstrated the need to enhance the operator’s situation awareness (SA). The long-term objective of this research is to integrate valuable technologies into the grid operator environment that support decision making under normal and abnormal operating conditions and remove non-technical barriers to enable the optimum use of these technologies by individuals working alone and as a team. More specifically, the research aims to identify methods and principles to increase SA of grid operators in the context of system conditions that are representative or common across many operating entities and develop operationally relevant experimental methods for studying technologies and operational practices which contribute to SA. With increasing complexity and interconnectivity of the grid, the scope and complexity of situation awareness have grown. New paradigms are needed to guide research and tool development aimed to enhance and improve operations. In reviewing related research, operating practices, systems, and tools, the present study established a taxonomy that provides a perspective on research and development surrounding power grid situation awareness and clarifies the field of human factors/SA for grid operations. Information sources that we used to identify critical factors underlying SA included interviews with experienced operational personnel, available historical summaries and transcripts of abnormal conditions and outages (e.g., the August 14, 2003 blackout), scientific literature, and operational policies/procedures and other documentation. Our analysis of August 2003 blackout transcripts and interviews adopted a different perspective than previous analyses of this material, and we complemented this analysis with additional interviews. Based on our analysis and a broad

  10. Space debris proximity analysis in powered and orbital phases during satelitte launch

    Science.gov (United States)

    Bandyopadhyay, P.; Sharma, R.; Adimurthy, V.

    The need to protect a launch vehicle in its ascent phase as well as the payload upon injection in particular and to prevent generation of debris in general through collision has led to many recent developments in the methodologies of SPAce DEbris PROximity (SPADEPRO) analysis, which is required for COLlision Avoidance or COLA studies. SPADEPRO refers to assessment of collision risk between catalogued resident space objects and launch vehicle or satellite of interest. The detection of close approaches to satellites/launch vehicles during the launch and early post-deployment phase of their lifetimes is an important subset of the overall problem. Potential collisions during this period can usually be avoided by adjusting the time of launch within a specified launch window. In Ref- 1 a series of filters through which candidate objects have to pass before determining its close approach distances from either analytical propagators like SGP4/SDP4 or any numerical prediction package, has been described. Unfortunately, this detection technique cannot strictly be applied since assumption of orbital motion is violated when powered launch trajectories are considered. Ref- 2 has proposed an algorithm for determining launch window blackout intervals based on the avoidance of close approaches for trajectories, which are fixed relative to an Earth Centered Earth Fixed (ECEF) reference frame. In this paper, authors approximate the powered launch trajectory into a series of orbital trajectories so that those trajectories envelope the powered launch trajectory in position-velocity phase space. Following this, filters described in Ref- 1 have been utilized to find out potential candidates from resident space objects. In Ref- 2, 3 &4 the blackout period has been observed when the closest approach distance is below a certain threshold. Instead, in this paper authors use collision probability, considering dispersions in respective trajectories of resident space objects and launch vehicle

  11. Basic Research Needs for Superconductivity. Report of the Basic Energy Sciences Workshop on Superconductivity, May 8-11, 2006

    Energy Technology Data Exchange (ETDEWEB)

    Sarrao, J.; Kwok, W-K; Bozovic, I.; Mazin, I.; Seamus, J. C.; Civale, L.; Christen, D.; Horwitz, J.; Kellogg, G.; Finnemore, D.; Crabtree, G.; Welp, U.; Ashton, C.; Herndon, B.; Shapard, L.; Nault, R. M.

    2006-05-11

    As an energy carrier, electricity has no rival with regard to its environmental cleanliness, flexibility in interfacing with multiple production sources and end uses, and efficiency of delivery. In fact, the electric power grid was named ?the greatest engineering achievement of the 20th century? by the National Academy of Engineering. This grid, a technological marvel ingeniously knitted together from local networks growing out from cities and rural centers, may be the biggest and most complex artificial system ever built. However, the growing demand for electricity will soon challenge the grid beyond its capability, compromising its reliability through voltage fluctuations that crash digital electronics, brownouts that disable industrial processes and harm electrical equipment, and power failures like the North American blackout in 2003 and subsequent blackouts in London, Scandinavia, and Italy in the same year. The North American blackout affected 50 million people and caused approximately $6 billion in economic damage over the four days of its duration. Superconductivity offers powerful new opportunities for restoring the reliability of the power grid and increasing its capacity and efficiency. Superconductors are capable of carrying current without loss, making the parts of the grid they replace dramatically more efficient. Superconducting wires carry up to five times the current carried by copper wires that have the same cross section, thereby providing ample capacity for future expansion while requiring no increase in the number of overhead access lines or underground conduits. Their use is especially attractive in urban areas, where replacing copper with superconductors in power-saturated underground conduits avoids expensive new underground construction. Superconducting transformers cut the volume, weight, and losses of conventional transformers by a factor of two and do not require the contaminating and flammable transformer oils that violate urban safety

  12. Dynamic Analysis of Diesel Generator System after Loss of Offsite Power Event Occurring in Nuclear Power Plants%核电厂丧失厂外电源事件下柴油发电机系统动态响应分析

    Institute of Scientific and Technical Information of China (English)

    李哲

    2012-01-01

    将系统可靠性分析方法GO法与Markov法相结合,对核电厂概率安全分析(PSA)中厂外电源丧失(LOOP)后柴油发电机应急响应系统在24h内缓解全厂断电(SBO)事件中的动态过程进行分析,解决了维修相关存在下可修系统可靠性精确计算问题,并通过创建GO法“备用门”操作符真实地模拟应急响应系统工作的逻辑关系.通过将2种可靠性分析方法相结合使用的尝试,使之与柴油发电机应急响应系统存在维修相关的实际情况相适应,拓展了2种方法的分析领域,同时能够更为精确地得出SBO对系统安全运行的影响.%Based on the GO methodology and Markov method, the dynamic analysis of emergency diesel generator system for protecting the nuclear power plant from Station Blackout, which is caused by Loss of Offsite Power event, is made with duration of 24 hours. In addition, the accurate reliability calculation problem is solved for the repairable system with dependant maintenance relation, and the logic relation of emergency response system is fully simulated by creating the "Backup Operator" of the GO methodology. By combining the two reliability analysis methods, which is used suitably for the emergency response system of diesel generators with dependant maintenance relation, the application range for the two methods is expanded, and the effect of station blackout event on the safety operation of nuclear power plants can be obtained more accurately.

  13. Construction and Application of Power Grid Operation Risk Assessment and Rating System%电网运行风险评估与定级体系的构建及应用

    Institute of Scientific and Technical Information of China (English)

    王一枫; 汤伟; 刘路登; 郭创新

    2015-01-01

    To solve engineering application defects such as lack of assessment details and risk information in the risk index system,this paper presents a power grid operation risk assessment and rating system.Firstly,redefine the risk structure as a set of risk grade,risk kind,risk probability,risk severity,reason set and consequence set,while classifying risk categories as loss of load,overload,voltage deviation,grid splitting,blackout of plant/station,and blackout of important users.Secondly, design the rating method of risk probability grade,risk severity grade and risk grade.Finally,divide the system flow into five parts as information collection,risk identification,risk assessment,risk rating and risk warning,and illustrate the system application effects in Dispatch and Control Center of State Grid Anhui Electric Power Company.%为解决风险指标体系在工程应用中存在的评估细节反映不足和风险信息不够充分的缺陷,文中提出了一种电网运行风险评估与定级体系。首先,在结构上将风险重新定义为等级、类别、概率、严重程度、原因集和后果集的集合,在类别上将风险分为减供负荷、重载或过载、电压偏移、电网解列、厂站全停和重要用户全停。其次,设计了各类风险发生概率等级、严重程度等级及风险综合等级的定级方法。最后,从信息采集、风险辨识、风险评估、风险定级和风险预警五个环节设计了体系流程,并对该体系的应用效果作了说明。

  14. Research on Improving GPS Communication Performance in Near Space by Additional Magnetic Field%外加磁场改善临近空间GP S通信研究

    Institute of Scientific and Technical Information of China (English)

    周天翔; 陈长兴; 蒋金; 任晓岳; 胡明睿

    2016-01-01

    针对飞行器以高超声速穿过临近空间大气层产生的通信“黑障”问题,提出了外加磁场,改变电磁环境以解决通信黑障问题的方案。依据美国RAM C 提供的飞行试验数据,建立磁化等离子体鞘套模型,通过数值计算方法分析了磁场强度、等离子体厚度、等离子体碰撞频率和等离子体电子密度对 GPS 信号传输的反射和衰减特性。综合分析仿真表明:对处于低频段的GPS信号,通过在航天器周围添加磁场,能够明显改善电磁波在等离子体鞘套中的传输性能,当外加磁场强度大于2 T时,GPS信号在等离子体鞘套中的传输衰减值均在5 dB以下,有效减缓了黑障对于电磁波传输的影响,达到了较好的通信状态。%Aimed at the communication blackout problem that a hypersonic aircraft passes through near space atmosphere,a method that an additional magnetic field is used to change electromagnetic environ-ments of plasma sheath is proposed.According to the data provided by radio attenuation measurement C (RAM C)voyage experiment,a model of plasma sheath is established.This paper analyzes the magnetic field intensity and parameters of plasma including plasma thickness,plasma density,plasma collision fre-quency to get the reflection and attenuation properties of GPS wave propagation in plasma sheath by nu-merical calculation.Comprehensive analysis shows that additional the magnetic field around aircraft can ef-fectively solve the"communication blackout"problem especially directed against GPS signal in low fre-quency.When magnetic field intensity is over 2 T,the transmission attenuation values of GPS signal in plasma sheath are all 5 dB below.The communication state is perfect.

  15. CRISP. Dependable ICT Support of Power Grid Operations

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, R.; Mellstrand, P.; Tornqvist, B. [Blekinge Institute of Technology BTH, Karlskrona (Sweden); Akkermans, H. [EnerSearch, Malmoe (Sweden)

    2005-03-15

    This deliverable D2.4 Dependable ICT support 0f Power Grid Operations is a link between deliverable D1.6 Information security models and their economics and planned activities in WP III, that is, Implementation, Experiments and Tests. Background CRISP material includes deliverables of D2.2 Design document and multi-agent simulation tool for distributed demand-supply matching and D2.3 Design document and simulation tool for diagnostics of high-DG power networks. Furthermore there are links between this document and the deliverable D1.7 Report on distributed network architectures and D1.8 Reports on case study simulations and results. In short, this document specifies and extends the general background on security models and dependability models of deliverable D1.6 with CRISP specific material of D2.2 and D2.4 towards the experiments and tests of WP III. The focus of this deliverable is on dependable ICT support of power grid operation. By recasting the three CRISP experiments into three Scenarios in Chapter 2 we claim that we have a good description of benefits and challenges related to future virtual utilities. Among the challenges are securing trustworthy operation from a technical operation side (avoid disturbances such as blackouts) as wee as from a user-centric business point of view (value added power related services). Our investigation on proper means to safeguard operations of future virtual utilities begins with an assessment of lessons learned from recent (2003) big blackouts worldwide in Chapter 3. We propose an accident diagnosis and repair model (STAMP in Section 3.2) suitable for the complex socio-technical system we envisage for future cell-based virtual utilities. From this analysis and the background material from deliverable D1.6 Information security models and their economics, we then reassess the dependability concerns related to the CRISP related scenarios of Chapter 2. The deliverable provides some novel ideas and models that we claim are

  16. The potential for distributed generation in Japanese prototype buildings: A DER-CAM analysis of policy, tariff design, building energy use, and technology development (Japanese translation)

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Nan; Marnay, Chris; Firestone, Ryan; Gao, Weijun; Nishida, Masaru

    2004-10-15

    The August 2003 blackout of the northeastern U.S. and CANADA caused great economic losses and inconvenience to New York City and other affected areas. The blackout was a warning to the rest of the world that the ability of conventional power systems to meet growing electricity demand is questionable. Failure of large power systems can lead to serious emergencies. Introduction of on-site generation, renewable energy such as solar and wind power and the effective utilization of exhaust heat is needed, to meet the growing energy demands of the residential and commercial sectors. Additional benefit can be achieved by integrating these distributed technologies into distributed energy resource (DER) systems. This work demonstrates a method for choosing and designing economically optimal DER systems. An additional purpose of this research is to establish a database of energy tariffs, DER technology cost and performance characteristics, and building energy consumption for Japan. This research builds on prior DER studies at the Ernest Orlando Lawrence Berkeley National Laboratory (LBNL) and with their associates in the Consortium for Electric Reliability Technology Solutions (CERTS) and operation, including the development of the microgrid concept, and the DER selection optimization program, the Distributed Energy Resources Customer Adoption Model (DER-CAM). DER-CAM is a tool designed to find the optimal combination of installed equipment and an idealized operating schedule to minimize a site's energy bills, given performance and cost data on available DER technologies, utility tariffs, and site electrical and thermal loads over a test period, usually an historic year. Since hourly electric and thermal energy data are rarely available, they are typically developed by building simulation for each of six end use loads used to model the building: electric-only loads, space heating, space cooling, refrigeration, water heating, and natural-gas-only loads. DER-CAM provides a

  17. 计及火电机组启动过程的网架并行恢复策略%A Parallel Restoration Strategy for Power Network Considering the Start-up Process of Thermal Units

    Institute of Scientific and Technical Information of China (English)

    周敏; 刘艳

    2011-01-01

    在以火电机组为主构成的系统中,机组的启动恢复时间将决定大停电后网架重建的速度.文中采用电厂集控运行仿真机对火电机组的启动过程进行了研究,建立了机组累积启动时间与机组停机时间之间的关系.在此基础上,提出了一种网架并行恢复策略,即以每一恢复阶段的可用启动功率为约束,将待恢复的机组节点作为优先级别最高的负荷节点.采用Prim算法优化寻找尽可能多的并行恢复路径.针对IEEE 30节点系统的验证结果表明:所获得的重构顺序能够最大限度地利用启动功率,争取多台机组、多条路径的同时恢复,有效压缩了网架重构的时间,有助于快速、有序地组织系统的重构操作.%In power systems mainly consisting of thermal units, the time for units' start-up and restoration determines the duration of network reconfiguration following large-area blackout. Centralized-operation simulator for power plant is first employed to investigate the starting process of thermal units thereby establishing the relationship between start-up time and the cumulative downtime corresponding to typical unit types. Based on this, a parallel restoration strategy is proposed for reconstructing a power network. According to this strategy, the unit nodes are regarded as the load nodes with the highest priority and while being processed together with other load nodes. After available crank power in each stage is used as constraints, parallel restoration paths are optimized with Prim algorithm. Case studies with the IEEE 30-bus system verify that the reconfiguration scheme achieved can make full use of the crank power thereby restoring multi units and paths simultaneously so that the duration is reduced effectively. This is essential for organizing restoration scenarios rapidly and systematically following a large-scale blackout.

  18. Smart distribution system service restoration using distributed generation islanding technique%考虑分布式发电孤岛运行方式的智能配电网供电恢复策略研究

    Institute of Scientific and Technical Information of China (English)

    赵晶晶; 杨秀; 符杨

    2011-01-01

    鉴于传统的配电网供电恢复算法都没考虑分布式发电孤岛运行产生的影响,提出考虑DG孤岛运行方式下的智能配电网供电恢复算法.当配电网发生严重故障引起大面积停电时,对DG进行孤岛划分,DG按孤岛划分方案转入孤岛运行模式维持对孤岛内重要负荷供电.采用基于二进制粒子群优化算法的供电恢复算法对孤岛外非故障停电区域进行供电恢复,在维持孤岛内重要负荷供电的前提下最大限度地对孤岛外停电区域恢复供电.最后将该算法应用到33节点测试系统,仿真结果验证了该算法的有效性.%In view of the conventional distribution system service restoration methods ignoring the influence of the distributed generation (DG) islanding, a smart distribution system service restoration method using DG islanding technique is proposed. First, when serious failures result in large area power blackout, DG switches to the islanding operation mode using islanding algorithm to maintain the power supply for the important load. Second, a service restoration method based on the binary particle swarm optimization is proposed to restore non-failure power blackout area outside the islanding. On the premise of maintaining the important loads in the islanding, this method restores the loads outside the islanding to the maximal degree. At last, the service restoration method is exerted on 33-node feeder, and the simulation results demonstrate the validity of the method.

  19. 电力系统恢复控制在线决策方法%An On-line Decision-Making Method Applicable to Power System Restoration Control

    Institute of Scientific and Technical Information of China (English)

    赵达维; 刘天琪; 李兴源

    2013-01-01

    黑启动方案对非“全黑”停电场景的针对性和有效性存在不足。为此,提出一种电力系统恢复控制在线决策方法:兼顾可用发电容量裕度及同期并网点位置等因素,采用深度优先搜索法划分停电区域,并运用粗糙集理论的综合优势度评判方法使停电子区与恢复策略匹配。建立符合系统恢复特征的电源出力模型;在此基础上,考虑重要负荷快速恢复、网内机组发电份额和系统稳定等因素,设计恢复控制的2%There is insufficiency in the pertinence and effectiveness of black-start scheme used for non-overall blackout scene. Therefore, an online decision-making method for power system restoration control is proposed. Simultaneously considering the factors such as available generating capacity margin and the position of synchronization points, the outage areas are divided by depth first searching (DFS) and the comprehensive dominance calculation in rough set theory is utilized to make outage subareas matching with restoration strategy. Power source output models conforming to system restoration characteristics are built, on this basis, considering such factors as rapidly restoring important load, the generation share of units within the grid and system stability, a two-stage multi-objective optimization model for restoration control is designed. In view of the feature that the restoration process is naturally discretized by time intervals for dispatching and control, the proposed model is solved by dynamic programming. Simulation results of actual power grid show that the proposed method is feasible and effective, and it can provide decision-making reference for system operator to cope with blackout.

  20. Accidental Thawing of Embryos, Cryopreserved for Transfer. Two Italian cases, Milan and Rome.

    Science.gov (United States)

    Busardò, Francesco P; Vergallo, Gianluca Montanari; Turillazzi, Emanuela; Bolino, Giorgio; Vullo, Annamaria; Frati, Paola

    2016-01-01

    The bioethical and juridical debate on the status of frozen embryos sometimes adds new issues arising from new scientific evidence or by accidental occurrences that bring to the attention of the scientific community the need for new practical solutions. Within this scenario, there have been, in recent years, episodes concerning the accidental thawing of embryos, which have been cryopreserved for transfer. Two Italian cases (the Milan and the Rome cases) are here reported: the Milan case involves a couple undergoing artificial insemination. Three eggs were collected for insemination and two of them had been fertilized. During the night of 8/9 May 2007 a short circuit occurred, resulting in an electricity blackout, which caused the loss of the embryos in culture, which should have been transferred to the woman's uterus on 9 May. The couple applied for damage compensation from the hospital following the loss of the embryos. The case went to Court and the result was a judgment issued by the Milan civil court, which recognized that the centre was to blame for irreparable damage to the embryos. The Rome case, involves two couples (A and B) affected by sterility who applied to an authorized public centre to undergo an ART program. Following the medical procedures, two of the embryos produced were transferred to the woman in couple A and five were frozen, whereas three embryos produced by couple B were transferred to the uterus of the woman and six eggs were cryopreserved in the centre. Two years after the procedure there was an electricity blackout, and the backup electricity generator failed to function, causing the loss of the gametes and the embryos cryopreserved in the centre. Legal proceedings begun by the couples to obtain compensation for damages are still underway. The above reported cases have significantly intensified the bioethical debate on the lawfulness of such practices and on the fate of the cryopreserved embryos, at the same time opening new frontiers in

  1. Advanced transport protocols for space communications

    Science.gov (United States)

    Fang, Jian

    Satellite IP networks are characterized by high bit error rates, long propagation delays, low bandwidth feedback links, and persistent fades resulting from varying weather patterns. A new unicast transport protocol is designed to address all the above challenges. Two new algorithms, Jump Start and Quick Recovery, are presented to replace the traditional Slow Start algorithm and to recover rapidly from multiple segment losses within one window of data. The characteristics of satellite IP networks also distinguish satellite multicasting from multicasting in terrestrial wirelined networks. A reliable data multicast transport protocol, TCP-Peachtree, is proposed to solve the acknowledgment implosion and scalability problems in satellite IP networks. Developments in space technology are enabling the realization of deep space missions. The scientific data from these missions need to be delivered to the Earth successfully. To achieve this goal, the InterPlaNetary Internet is proposed as the Internet of the deep space planetary networks, which is characterized by extremely high propagation delays, high link errors, asymmetrical bandwidth, and blackouts. A reliable transport protocol, TP-Planet, is proposed for data traffic in the InterPlaNetary Internet. TP-Planet deploys rate-based additive-increase multiplicative-decrease (AIMD) congestion control and replaces the inefficient slow start algorithm with a novel Initial State algorithm that allows the capture of link resources in a very fast and controlled manner. A new congestion detection and control mechanism is developed and a Blackout State is incorporated into the protocol operation. Multimedia traffic is also one part of the aggregate traffic over InterPlaNetary Internet backbone links and it has additional requirements such as minimum bandwidth, smooth traffic, and error control. To address all the above challenges, RCP-Planet is proposed. RCP-Planet consists of two novel algorithms, i.e., Begin State and

  2. Overview of the X-33 Extended Flight Test Range

    Science.gov (United States)

    Mackall, D.; Sakahara, R.; Kremer, S.

    1998-01-01

    On July 1, 1996, the National Aeronautics and Space Administration signed a Cooperative Agreement No. NCC8-115 with Lockheed Martin Skunk Works to develop and flight test the X-33, a scaled version of a reusable launch vehicle. The development of an Extended Test Range, with range instrumentation providing continuous vehicle communications from Edwards Air Force Base Ca. to landing at Malmstrom Air Force Base Montana, was required to flight test the mach 15 vehicle over 950 nautical miles. The cooperative agreement approach makes Lockheed Martin Skunk Works responsible for the X-33 program. When additional Government help was required, Lockheed "subcontracted" to NASA Field Centers for certain work. It was through this mechanism that Dryden Flight Research Center became responsible for the Extended Test Range. The Extended Test Range Requirements come from two main sources: 1) Range Safety and 2) Lockheed Martin Skunk Works. The range safety requirements were the most challenging to define and meet. The X-33 represents a vehicle that launches like a rocket, reenters the atmosphere and lands autonomously like an aircraft. Historically, rockets have been launched over the oceans to allow failed rockets to be destroyed using explosive devices. Such approaches had to be reconsidered for the X-33 flying over land. Numerous range requirements come from Lockheed Martin Skunk Works for interface definitions with the vehicle communication subsystems and the primary ground operations center, defined the Operations Control Center. Another area of considerable interest was the reentry plasma shield that causes "blackout" of the radio frequency signals, such as the range safety commands. Significant work was spent to analyze and model the blackout problem using a cooperative team of experts from across the country. The paper describes the Extended Test Range a, an unique Government/industry team of personnel and range assets was established to resolve design issues and

  3. About the Power Generation Confirmation of the Induction Motor and the Influence on the Islanding Detection Device

    Science.gov (United States)

    Igarashi, Hironobu; Sato, Takashi; Miyamoto, Kazunori; Kurokawa, Kousuke

    The photovoltaic generation system must have protection device and islanding detection devices to connect with utility line of the electric power company. It is regulated in the technological requirement guideline and the electric equipment technology standard that the country provides. The islanding detection device detected purpose install for blackout due to the accident occurrence of the earth fault and the short-circuit in the utility line. When the islanding detection device detects the power blackout, it is necessary to stop the photovoltaic generation system immediately. If the photovoltaic generation system is not stopped immediately, electricity comes to charge the utility power line very at risk. We had already known that the islanding detection device can't detect the islanding phenomenon, if is there the induction motor in the loads. Authors decided to investigate the influence that the induction motors gave to the islanding detection device. The result was the load condition that the induction motors changed generator the voltage is restraining. Moreover, it was clarified that the time of the islanding was long compared with the load condition of not changing into the state of the generator. The value changes into the reactance of the induction motors according to the frequency change after the supply of electric power line stops. The frequency after the supply of electric power line stops changes for the unbalance the reactive power by the effect of the power rate constancy control with PLL of the power conditioner. However, the induction motors is also to the changing frequency, makes amends for the amount of reactive power, and the change in the frequency after the supply of electric power line stops as a result is controlled. When the frequency changed after the supply of electric power line stopped, it was clarified of the action on the direction where it made amends from the change of the constant for the amount of an invalid electric power, and

  4. Refuse Operation Fault Analysis of 110kV Lines and Its Disposal Measures%110kV线路拒动故障分析及解决措施

    Institute of Scientific and Technical Information of China (English)

    程钢; 宋汉蓉; 叶涛; 陈曦

    2012-01-01

    四川省德阳地区110kV电网是以一个220kV变电站为电源中心呈辐射状向各负荷变电站供电的运行方式,通过对220kV变电站110kV出线采用双回线并列运行且分别运行在两段母线上,当110kV单回线路发生故障时线路开关或线路保护拒动的分析,得出了220kV变电站110kV母线将发生电网大面积停电事故的结论,提出了采用改变电网运行方式消除外挂母联和调整保护方案(采用事故发生后以一较短时限先跳开220kV变电站110kV母联开关,再跳双回线路负荷侧开关的保护时限配合原则,保证故障母线与非故障母线隔离)两种解决措施,均可避免发生220kV变电站110kV母线全停的电网大面积停电事故.%110 kV power grid of Deyang area in Sichuan Province is a power supply center of 220 kV transformer substations, whose operation mode is radial power supply to the load transformer substation. This paper deeply analyzes the power grid structure and operation mode when 110 kV single loop line of 220 kV substation aborts. If the fault lines take place line switch or protection refuse operating, it will lead to 110 kV bus of 220 kV substation full cut-off and trigger large area blackout accident. So, it puts forward treatment measures including change the power grid operation mode to remove the cladding bar coupler or adjustment protection plan (when the accident happened, in a short time tripping off 110 kV bar coupler of 220 kV substations, then tripping off switch of double loop line load to ensure the fault bus bar isolation). These two measures can avoid 110 kV bus of 220 kV substations full cut-off and large area blackout accident.

  5. Critical infrastructure: impacts of natural hazards and consequences

    Science.gov (United States)

    Petrova, Elena

    2014-05-01

    Critical infrastructure such as oil and gas pipelines, transmission facilities, heat-, and water supply, lines of communications, roads, railways as well as air and water transport play the key role in social and economic development of every country. Therefore, accidents causing failures and breakdowns of critical infrastructure facilities have the most drastic consequences for the society, economy, and environment. For example, road accidents cause the highest number of fatalities and injuries all over the world, especially in the middle-income countries. The so-called "blackouts" or accidental losses of electric power and power outages entail serious social troubles and heavy economic losses. The pipeline ruptures and oil-tanker crashes accompanied by oil releases cause the most severe environmental and large material damages. Critical infrastructure facilities are most vulnerable to the impacts of natural hazards that trigger many accidents in them especially in the regions most at natural risk. The Russian Federation has more than 2.6 million km of transmission facilities, 940,000 km of roads, 102,000 km of inland waterways, 86,000 km of railways, and more than 70,000 km of trunk pipelines. Many facilities are beyond of their service life and need reconstruction. A very high level of deterioration and "human factor" are the main cause of accidents, ruptures, and crashes. However, natural hazards and disasters also play an essential (sometimes a leading) role in triggering or magnifying accidents in these objects. Thus, natural factors cause more than 70 percent of all "blackouts", about 20 percent of accidents at heat- and water supply systems and water accidents, five percent of pipeline ruptures, and about two to three percent of air crashes, road, and railway accidents. The influence of natural factors is stronger in the North-Western and Central parts of the European Russia, in Krasnodarsky Territory (South of Russia) and in Far East that are more exposed

  6. Demonstration of a Novel Synchrophasor-based Situational Awareness System: Wide Area Power System Visualization, On-line Event Replay and Early Warning of Grid Problems

    Energy Technology Data Exchange (ETDEWEB)

    Rosso, A.

    2012-12-31

    Since the large North Eastern power system blackout on August 14, 2003, U.S. electric utilities have spent lot of effort on preventing power system cascading outages. Two of the main causes of the August 14, 2003 blackout were inadequate situational awareness and inadequate operator training In addition to the enhancements of the infrastructure of the interconnected power systems, more research and development of advanced power system applications are required for improving the wide-area security monitoring, operation and planning in order to prevent large- scale cascading outages of interconnected power systems. It is critically important for improving the wide-area situation awareness of the operators or operational engineers and regional reliability coordinators of large interconnected systems. With the installation of large number of phasor measurement units (PMU) and the related communication infrastructure, it will be possible to improve the operators’ situation awareness and to quickly identify the sequence of events during a large system disturbance for the post-event analysis using the real-time or historical synchrophasor data. The purpose of this project was to develop and demonstrate a novel synchrophasor-based comprehensive situational awareness system for control centers of power transmission systems. The developed system named WASA (Wide Area Situation Awareness) is intended to improve situational awareness at control centers of the power system operators and regional reliability coordinators. It consists of following main software modules: • Wide-area visualizations of real-time frequency, voltage, and phase angle measurements and their contour displays for security monitoring. • Online detection and location of a major event (location, time, size, and type, such as generator or line outage). • Near-real-time event replay (in seconds) after a major event occurs. • Early warning of potential wide-area stability problems. The system has been

  7. A Study on Fission Product Behavior during a Severe Accident at APR1400 Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han-Chul [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Cho, Song-Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In this study, calculations have been carried out for a SBO sequence similar to the selected scenario, but a faster one with simple assumptions. Instead, a sensitivity study was carried out to take into account the effects of such differences on the fission product behavior. Probabilistic Safety Assessment (PSA) for Shin-Kori 3·4 nuclear power plants, which are APR1400 type reactors, were reviewed. After all, the representing scenarios were determined to be the sequences with station blackout (SBO), interfacing system LOCA (ISLOCA), and steam generator tube rupture (SGTR), which are similar to those of the U.S.NRC's State-of-the-Art Reactor Consequence Analyses (SOARCA) study. Among those sequences, SBO occupies the largest portion of the risk from severe accidents, and was selected to be analyzed at first about the fission product behavior in the containment. It includes events such as failure of the alternative AC power generator following a blackout event, successful operation of turbine-driven auxiliary feed water (AFW) pump, late recovery of offsite power before containment failure, in-vessel injection and successful actuation of cavity flooding system and spray system, and failure of hydrogen mitigation system. We use MELCOR 1.8.6 with the 35- and 2-cell compartment models of the containment. Since MELCOR does not treat organic iodide, we tried to make the results up by MELCOR-RAIM which is the MELCOR code coupled with RAIM, a stand-alone code developed for evaluation of the iodine behavior. In order to investigate the fission product behavior during a severe accident at APR1400, we have selected the representing scenarios with SBO, ISLOCA and SGTR. Among them, a SBO sequence similar to the selected scenario, but a faster one with simple assumptions, was analyzed using MELCOR v1.8.6 with 35-cell models of the containment. For the sensitivity analysis, we use the 2-cell containment model and the codes with the iodine chemistry model such as MELCOR with

  8. Understanding the response of commercial and institutional organizations to the California energy crisis. A report to the California Energy Commission - Sylvia Bender, Project Manager

    Energy Technology Data Exchange (ETDEWEB)

    Lutzenhiser, Loren; Janda, Kathryn; Kunkle, Rick; Payne, Christopher

    2002-07-24

    Beginning in the summer of 2000, California experienced serious energy supply problems, sharp increases in wholesale (and retail) electricity and natural gas prices, and isolated blackouts. In response to the rapidly worsening electricity situation in California in late 2000, the state set, as an initial goal, the reduction of the state's peak demand for the summer of 2001 by 5,000 megawatts. To meet this goal, the governor and legislature took a variety of steps to enhance supply, encourage rapid voluntary reductions in demand, and provide incentives for actions that would result in load reductions. Three bills-Assembly Bill 970, Senate Bill X1 5 and Assembly Bill X1 29-allocated roughly $950 million for consumption and demand reduction programs. The governor also enacted a variety of additional measures, including the ''Flex Your Power'' (media awareness and direct business involvement) campaign, requirements for retail sector outdoor lighting reductions, and toughening of energy efficiency building codes. There were, in fact, significant reductions in electricity demand in California during the summer of 2001 and the large number of expected supply disruptions was avoided. To understand the nature of these demand reductions and the motivations for consumer response, Washington State University (WSU) undertook a study for the California Energy Commission (CEC) focusing on conservation behavior in the residential, commercial, and agricultural sectors. The research presented in this report represents an exploration of the response of commercial and institutional organizations to the California energy situation and the unique set of influences that existed during this time. These influences included informational messages and media attention, program interventions, price changes, and external triggering events (e.g., blackouts). To better understand the effects of these influences on organizational response to the energy situation, we

  9. Lights of Democracy, Authority and Liberty-On the History of News Legal System in Burma over the Past 160 Years%开明、威权与自由之光--160年缅甸新闻法制史管窥

    Institute of Scientific and Technical Information of China (English)

    展江; 黄晶晶

    2013-01-01

    缅甸曾经是亚洲享有最充分的新闻自由的国家,但是到了20世纪中期以后,随着1962年军事政变,缅甸由一个亚洲较富裕国家变成了落后国家,新闻界则经历了长达半个世纪的新闻管制。2011年,缅甸开启民主化政治改革,新闻界也随之开始了改革之路。通过梳理缅甸历史上的新闻自由、二战后军政府对新闻的管制和媒体的抗争以及正在进行的政治新闻变革举措,可以揭示出一个当代威权主义国家刚刚开始的媒体和政治转型之路。%Burma used to be a country which enjoyed the freedom of press in Asia during the 19th century.However, after the military coup in 1962, the press in Burma experienced more than half a century of news blackout, drawing back from a rich country in Asia to a backward one.In 2011, due to the launching of the political and democratic reform, the press in Burma started its reforming process.This paper aims to discuss the history of news development in Burma, including the freedom of press in the past, the news blackout after the 2nd World War by the military government and the struggle of media, and the polit-ical, news reform at the moment.In this way, an authoritative nation with news and political change on its way is to be presen-ted.

  10. Smart transmission grids - benefits and risks; Redes de transmision inteligente. Beneficios y riesgos

    Energy Technology Data Exchange (ETDEWEB)

    Velasco-Ramirez, E.; Angeles-Camacho, C. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mails: TVelascoR@iingen.unam.mx; CAngelesC@ii.unam.mx; Garcia-Martinez, M. [Instituto Tecnologico de Toluca, Estado de Mexico (Mexico)]. E-mail: mgarciam@ittoluca.edu.mx

    2013-01-15

    Nowadays the Power Systems are working near their stability limits, for this reason it is necessary and essential a transition to new transmission systems that ensure efficient delivery of electrical energy, with the objective to prevent blackouts that cause significant losses in the economy of any country in the world. This paper analyzes important elements to consider having a healthy and efficient transition from a power grid vertically integrated into a smart transmission grid. A comparative analysis in the model, development, benefits and risks of the implementation of these systems, between two of the main marc of references of smart grids, the EU and the USA is presented. [Spanish] Actualmente los sistemas electricos operan cada vez mas cercanos a sus limites de estabilidad, es por ello que se hace necesaria y primordial la transicion hacia nuevos sistemas de transmision que garanticen la eficiente entrega de la energia electrica, evitando con ello cortes de energia que generan importantes perdidas en la economia de cualquier pais del mundo. En este documento se realiza un analisis de los elementos necesarios para una sana y eficiente transicion de una red de transmision electrica verticalmente, integrada hacia una red de transmision inteligente. Se presenta un analisis comparativo entre dos de los marcos de referencia mas importantes, el de la UE y el de EUA, en el modelo, desarrollo, beneficios y riesgos en la implementacion de estos sistemas.

  11. Modeling and Vulnerability Analysis of Cyber-Physical Power Systems Considering Network Topology and Power Flow Properties

    Directory of Open Access Journals (Sweden)

    Jia Guo

    2017-01-01

    Full Text Available Conventional power systems are developing into cyber-physical power systems (CPPS with wide applications of communication, computer and control technologies. However, multiple practical cases show that the failure of cyber layers is a major factor leading to blackouts. Therefore, it is necessary to discuss the cascading failure process considering cyber layer failures and analyze the vulnerability of CPPS. In this paper, a CPPS model, which consists of cyber layer, physical layer and cyber-physical interface, is presented using complex network theory. Considering power flow properties, the impacts of cyber node failures on the cascading failure propagation process are studied. Moreover, two vulnerability indices are established from the perspective of both network structure and power flow properties. A vulnerability analysis method is proposed, and the CPPS performance before and after cascading failures is analyzed by the proposed method to calculate vulnerability indices. In the case study, three typical scenarios are analyzed to illustrate the method, and vulnerabilities under different interface strategies and attack strategies are compared. Two thresholds are proposed to value the CPPS vulnerability roughly. The results show that CPPS is more vulnerable under malicious attacks and cyber nodes with high indices are vulnerable points which should be reinforced.

  12. Impact of X-Class Flares on the Polar Ionosphere

    Science.gov (United States)

    Sojka, J. J.; Lewis, M.; David, M.; Schunk, R. W.; Nicolls, M. J.; Woods, T. N.; Eparvier, F.

    2014-12-01

    The ionospheric impact of X-class and large M-class flares has posed severe observational challenges for the ionosonde community. The very strong high frequency (HF) radio absorption associated with the X-class flares creates black-out conditions making ionosonde observations impossible. Similarly incoherent scatter radar (ISR) observations have generated only a few X-class flare impact observations because of limited duty cycle of these radars. With the advent of the NSF Advanced Modular Incoherent Scatter Radar (AMISR) technology it has become possible to operate 24/7 with better than 10 minute cadence. The PFISR, located at Poker Flat, Alaska, has operated in such a mode since March 2007. This has provide a data base that has captured many X-class flares. The irradiance from a subset of these were also observed by the Extreme Ultraviolet Variability Experiment (EVE) on the NASA Solar Dynamics Observatory (SDO) satellite. Hence we are in a position to evaluate modeling approaches that describes E-region ionization via energetic photons as well as the subsequent ionization caused by these photoelectrons. A key issue remains, that associated with the Auger ionization process. This latter topic's relevance will be described from the modeling and future observational needs point of view. The extension of this study into the central polar cap using Resolute Bay, Canada, AMISRs will be discussed.

  13. A Green Prison: The Santa Rita Jail Campus Microgrid

    Energy Technology Data Exchange (ETDEWEB)

    Marnay, Chris; DeForest, Nicholas; Lai, Judy

    2012-01-22

    A large microgrid project is nearing completion at Alameda County’s twenty-two-year-old 45 ha 4,000-inmate Santa Rita Jail, about 70 km east of San Francisco. Often described as a green prison, it has a considerable installed base of distributed energy resources (DER) including an eight-year old 1.2 MW PV array, a five-year old 1 MW fuel cell with heat recovery, and considerable efficiency investments. A current US$14 M expansion adds a 2 MW-4 MWh Li-ion battery, a static disconnect switch, and various controls upgrades. During grid blackouts, or when conditions favor it, the Jail can now disconnect from the grid and operate as an island, using the on-site resources described together with its back-up diesel generators. In other words, the Santa Rita Jail is a true microgrid, or μgrid, because it fills both requirements, i.e. it is a locally controlled system, and it can operate both grid connected and islanded. The battery’s electronics includes Consortium for Electric Reliability Technology (CERTS) Microgrid technology. This enables the battery to maintain energy balance using droops without need for a fast control system.

  14. The probability of containment failure by direct containment heating in Zion. Supplement 1

    Energy Technology Data Exchange (ETDEWEB)

    Pilch, M.M.; Allen, M.D.; Stamps, D.W.; Tadios, E.L. [Sandia National Labs., Albuquerque, NM (United States); Knudson, D.L. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1994-12-01

    Supplement 1 of NUREG/CR-6075 brings to closure the DCH issue for the Zion plant. It includes the documentation of the peer review process for NUREG/CR-6075, the assessments of four new splinter scenarios defined in working group meetings, and modeling enhancements recommended by the working groups. In the four new scenarios, consistency of the initial conditions has been implemented by using insights from systems-level codes. SCDAP/RELAP5 was used to analyze three short-term station blackout cases with Different lead rates. In all three case, the hot leg or surge line failed well before the lower head and thus the primary system depressurized to a point where DCH was no longer considered a threat. However, these calculations were continued to lower head failure in order to gain insights that were useful in establishing the initial and boundary conditions. The most useful insights are that the RCS pressure is-low at vessel breach metallic blockages in the core region do not melt and relocate into the lower plenum, and melting of upper plenum steel is correlated with hot leg failure. THE SCDAP/RELAP output was used as input to CONTAIN to assess the containment conditions at vessel breach. The containment-side conditions predicted by CONTAIN are similar to those originally specified in NUREG/CR-6075.

  15. Backup and Ultimate Heat Sinks in CANDU Reactors For Prolonged SBO Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Nitheanandan, T.; Brown, M. J. [Atomic Energy of Canada Limited, Ontario (Canada)

    2013-10-15

    In a pressurized heavy water reactor, following loss of the primary coolant, severe core damage would begin with the depletion of the liquid moderator, exposing the top row of internally-voided fuel channels to steam cooling conditions on the inside and outside. The uncovered fuel channels would heat up, deform and disassemble into core debris. Large inventories of water passively reduce the rate of progression of the accident, prolonging the time for complete loss of engineered heat sinks. The efficacy of available backup and ultimate heat sinks, available in a CANDU 6 reactor, in mitigating the consequences of a prolonged station blackout scenario was analysed using the MAAP4-CANDU code. The analysis indicated that the steam generator secondary side water inventory is the most effective heat sink during the accident. Additional heat sinks such as the primary coolant, moderator, calandria vault water and end shield water are also able to remove decay heat; however, a gradually increasing mismatch between heat generation and heat removal occurs over the course of the postulated event. This mismatch is equivalent to an additional water inventory estimated to be 350,000 kg at the time of calandria vessel failure. In the Enhanced CANDU 6 reactor ∼2,040,000 kg of water in the reserve water tank is available for prolonged emergencies requiring heat sinks.

  16. Forecasting decadal and shorter time-scale solar cycle features

    Science.gov (United States)

    Dikpati, Mausumi

    2016-07-01

    Solar energetic particles and magnetic fields reach the Earth through the interplanetary medium and affect it in various ways, producing beautiful aurorae, but also electrical blackouts and damage to our technology-dependent economy. The root of energetic solar outputs is the solar activity cycle, which is most likely caused by dynamo processes inside the Sun. It is a formidable task to accurately predict the amplitude, onset and peak timings of a solar cycle. After reviewing all solar cycle prediction methods, including empirical as well as physical model-based schemes, I will describe what we have learned from both validation and nonvalidation of cycle 24 forecasts, and how to refine the model-based schemes for upcoming cycle 25 forecasts. Recent observations indicate that within a solar cycle there are shorter time-scale 'space weather' features, such as bursts of various forms of activity with approximately one year periodicity. I will demonstrate how global tachocline dynamics could play a crucial role in producing such space weather. The National Center for Atmospheric Research is sponsored by the National Science Foundation.

  17. Medical System Concept of Operations for Mars Exploration Missions

    Science.gov (United States)

    Urbina, Michelle; Rubin, D.; Hailey, M.; Reyes, D.; Antonsen, Eric

    2017-01-01

    Future exploration missions will be the first time humanity travels beyond Low Earth Orbit (LEO) since the Apollo program, taking us to cis-lunar space, interplanetary space, and Mars. These long-duration missions will cover vast distances, severely constraining opportunities for emergency evacuation to Earth and cargo resupply opportunities. Communication delays and blackouts between the crew and Mission Control will eliminate reliable, real-time telemedicine consultations. As a result, compared to current LEO operations onboard the International Space Station, exploration mission medical care requires an integrated medical system that provides additional in-situ capabilities and a significant increase in crew autonomy. The Medical System Concept of Operations for Mars Exploration Missions illustrates how a future NASA Mars program could ensure appropriate medical care for the crew of this highly autonomous mission. This Concept of Operations document, when complete, will document all mission phases through a series of mission use case scenarios that illustrate required medical capabilities, enabling the NASA Human Research Program (HRP) Exploration Medical Capability (ExMC) Element to plan, design, and prototype an integrated medical system to support human exploration to Mars.

  18. Hydro-Quebec and geomagnetic storms: measurement techniques, effects on transmission network and preventive actions since 1989.

    Science.gov (United States)

    Beland, J.

    In March 1989 the province of Quebec in Canada suffered an almost complete blackout during a severe geomagnetic storm. Millions of Hydro-Québec's customers have been left without electricity for several hours. Fifteen years later, many changes have been implemented to avoid the repetition of such an event. Among them, we now have two measurement systems (one primary and one backup) monitoring ground induced current (GIC) effects on the grid in real time. Those systems are described and examples of data acquired during major storms (as in late October 2003) are given. To be informed in advance of a probable GIC occurrence, HQ now relies on a specialized organization providing geomagnetic activity alert and forecast. Following an alert or the detection of GIC effects on the network exceeding a minimal threshold, special operation rules become in effect with the objective of ensuring maximum stability and safety margin. Another major improvement is the introduction of series capacitors on several 735 kV lines, which increases network stability and also block GIC circulation. In conclusion, HQ now believes that its network can survive to any realistic geomagnetic storm.

  19. Re-entry communication through a plasma sheath using standing wave detection and adaptive data rate control

    Science.gov (United States)

    Xie, Kai; Yang, Min; Bai, Bowen; Li, Xiaoping; Zhou, Hui; Guo, Lixin

    2016-01-01

    Radio blackout during the re-entry has puzzled the aerospace industry for decades and has not yet been completely resolved. To achieve a continuous data link in the spacecraft's re-entry period, a simple and practicable communication method is proposed on the basis that (1) the electromagnetic-wave backscatter of the plasma sheath affects the voltage standing wave ratio (VSWR) of the antenna, and the backscatter is negatively correlated to transmission components, and (2) the transmission attenuation caused by the plasma sheath reduces the channel capacity. We detect the voltage standing wave ratio changes of the antenna and then adjust the information rate to accommodate the varying channel capacity, thus guaranteeing continuous transmission (for fewer critical data). The experiment was carried out in a plasma generator with an 18-cm-thick and 30-cm-diameter hollow propagation path, and the adaptive communication was implemented using spread spectrum frequency, shift key modulation with a variable spreading factor. The experimental results indicate that, when the over-threshold of VSWR was detected, the bit rate reduced to 250 bps from 4 Mbps automatically and the tolerated plasma density increased by an order of magnitude, which validates the proposed scheme. The proposed method has little additional cost, and the adaptive control does not require a feedback channel. The method is therefore applicable to data transmission in a single direction, such as that of a one-way telemetry system.

  20. SOSPO-SP: Secure Operation of Sustainable Power Systems Simulation Platform for Real-Time System State Evaluation and Control

    DEFF Research Database (Denmark)

    Morais, Hugo; Vancraeyveld, Pieter; Pedersen, Allan Henning Birger

    2014-01-01

    New challenges are arising in managing power systems as these systems become more complex due to the use of high levels of distributed generation, mainly based on renewable energy sources, and due to the competitive environment within the power sector. At the same time, the use of Phasor Measurem...... in a closed-loop, integrating new real-time assessment methods to provide useful information to operators in power system control centers and to develop new control methodologies that handle emergency situations and avoid power system blackouts....... Measurement Units (PMUs) provides more information and enables wide-area monitoring with accurate timing. One of the challenges in the near future is converting the high quantity and quality of information provided by PMUs into useful knowledge about operational state of a global system. The use of real......-time simulation in closed-loop is essential to develop and validate new real-time applications of wide-area PMU data. This paper presents a simulation platform developed within the research project Secure Operation of Sustainable Power Systems (SOSPO). The SOSPO simulation platform (SOSPO-SP) functions...

  1. Monitoring the performance of Aux. Feedwater Pump using Smart Sensing Model

    Energy Technology Data Exchange (ETDEWEB)

    No, Young Gyu; Seong, Poong Hyun [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2015-10-15

    Many artificial intelligence (AI) techniques equipped with learning systems have recently been proposed to monitor sensors and components in NPPs. Therefore, the objective of this study is the development of an integrity evaluation method for safety critical components such as Aux. feedwater pump, high pressure safety injection (HPSI) pump, etc. using smart sensing models based on AI techniques. In this work, the smart sensing model is developed at first to predict the performance of Aux. feedwater pump by estimating flowrate using group method of data handing (GMDH) method. If the performance prediction is achieved by this feasibility study, the smart sensing model will be applied to development of the integrity evaluation method for safety critical components. Also, the proposed algorithm for the performance prediction is verified by comparison with the simulation data of the MARS code for station blackout (SBO) events. In this study, the smart sensing model for the prediction performance of Aux. feedwater pump has been developed. In order to develop the smart sensing model, the GMDH algorithm is employed. The GMDH algorithm is the way to find a function that can well express a dependent variable from independent variables. This method uses a data structure similar to that of multiple regression models. The proposed GMDH model can accurately predict the performance of Aux.

  2. See No Evil Write No Evil: Sexual Deviance In African Literature During Colonialism

    Directory of Open Access Journals (Sweden)

    Wazha Lopang

    2014-10-01

    Full Text Available This paper argues that writers of African literature during colonialism differed in their portrayal of sexuality, particularly that which was considered deviant by nature, because of their need to build an ‘upright’ African image, no matter how artificial this was. The paper looks at how the political environment dictated sexual expression amongst characters and that the urban setting was more candid in its narrative style. There was also a total blackout on homosexuality between characters and where this took place, it was presented as something that was alien to the African culture in general and to the personality in particular. Writers who depicted pre-colonial settings limited sexuality to procreation and as a comment to the African’s link with the ancestors. There is also a correlation between the geographic location of texts and the degree of sexual expression that the writer engages in. As such the paper argues that sexual deviance is depicted as a matter of geography over and above thematic concerns.

  3. Awareness On Microgrids And Various Protection Issues To Overcome In It

    Directory of Open Access Journals (Sweden)

    Rachna Verma

    2015-05-01

    Full Text Available ABSTRACT As we know India faces problem of Power blackout every year due to the overloading on the main electrical grid. To avoid the above problem Microgrids are the best solution. Basically Microgrids are the small version of electrical grid. They are independent power system. Microgrids can be connected with renewable energy sources such as solar and wind. The use of renewable energy introduces the need of various storing devices and supplies it whenever required. Microgrids can provide wide range of applications in buildings military camps and corporateacademic campuses etc. They can have efficient and effective provision of electricity to off-grid areas as well as keep the lights on in times of crisis for critical applications like hospital. Though Microgrids being so advantageous it has several technical challenging issues to overcome i.e. voltage and frequency control islanding and its protection in Microgrids. This paper discusses the overview of Microgrids and issue to overcome in it-its Protection.

  4. Application of Meta-Heuristic Techniques for Optimal Load Shedding in Islanded Distribution Network with High Penetration of Solar PV Generation

    Directory of Open Access Journals (Sweden)

    Mohammad Dreidy

    2017-01-01

    Full Text Available Recently, several environmental problems are beginning to affect all aspects of life. For this reason, many governments and international agencies have expressed great interest in using more renewable energy sources (RESs. However, integrating more RESs with distribution networks resulted in several critical problems vis-à-vis the frequency stability, which might lead to a complete blackout if not properly treated. Therefore, this paper proposed a new Under Frequency Load Shedding (UFLS scheme for islanding distribution network. This scheme uses three meta-heuristics techniques, binary evolutionary programming (BEP, Binary genetic algorithm (BGA, and Binary particle swarm optimization (BPSO, to determine the optimal combination of loads that needs to be shed from the islanded distribution network. Compared with existing UFLS schemes using fixed priority loads, the proposed scheme has the ability to restore the network frequency without any overshooting. Furthermore, in terms of execution time, the simulation results show that the BEP technique is fast enough to shed the optimal combination of loads compared with BGA and BPSO techniques.

  5. Hurdling barriers through market uncertainty: Case studies ininnovative technology adoption

    Energy Technology Data Exchange (ETDEWEB)

    Payne, Christopher T.; Radspieler Jr., Anthony; Payne, Jack

    2002-08-18

    The crisis atmosphere surrounding electricity availability in California during the summer of 2001 produced two distinct phenomena in commercial energy consumption decision-making: desires to guarantee energy availability while blackouts were still widely anticipated, and desires to avoid or mitigate significant price increases when higher commercial electricity tariffs took effect. The climate of increased consideration of these factors seems to have led, in some cases, to greater willingness on the part of business decision-makers to consider highly innovative technologies. This paper examines three case studies of innovative technology adoption: retrofit of time-and-temperature signs on an office building; installation of fuel cells to supply power, heating, and cooling to the same building; and installation of a gas-fired heat pump at a microbrewery. We examine the decision process that led to adoption of these technologies. In each case, specific constraints had made more conventional energy-efficient technologies inapplicable. We examine how these barriers to technology adoption developed over time, how the California energy decision-making climate combined with the characteristics of these innovative technologies to overcome the barriers, and what the implications of hurdling these barriers are for future energy decisions within the firms.

  6. Wasauksing wind project

    Energy Technology Data Exchange (ETDEWEB)

    Beaucage, J. [Wasauksing First Nation, ON (Canada)

    2004-07-01

    This presentation outlined Northern Windpower's proposed Wasauksing project which involves the installation of a single 2 MW wind turbine on Wasauksing Island on the northeastern edge of Georgian Bay. The 7,700 hectare island has a population of about 275 residents who face frequent power outages. This presentation described some of the benefits of the Wasauksing wind project. The project would stabilize the island's grid and reduce dependency on the existing grid which demonstrated vulnerability during the blackout of August 2003. It would also reduce or eliminate monthly household electricity bills and create jobs and revenue for the community. In addition to environmental benefits the socio-economic benefits include tourism and the opportunity to develop the associated infrastructure such as roads and transmission lines. It is expected that all the homes on the island will consume only 10 per cent of the turbine's maximum output and excess electricity will be sold to the market through net metering. A wind power study which measured wind speeds revealed that the Three Mile Point, a non-developed part of the island, is the most suitable site for the proposed wind turbine. figs.

  7. Thermal Hydraulic design parameters study for severe accidents using neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Chang Hyun; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Chang, Keun Sun [Sunmoon University, Asan (Korea, Republic of)

    1997-12-31

    To provide the information on severe accident progression is very important for advanced or new type of nuclear power plant (NPP) design. A parametric study, therefore, was performed to investigate the effect of thermal hydraulic design parameters on severe accident progression of pressurized water reactors (PWRs). Nine parameters, which are considered important in NPP design or severe accident progression, were selected among the various thermal hydraulic design parameters. The backpropagation neural network (BPN) was used to determine parameters, which might more strongly affect the severe accident progression, among nine parameters. For training, different input patterns were generated by the latin hypercube sampling (LHS) technique and then different target patterns that contain core uncovery time and vessel failure time were obtained for Young Gwang Nuclear (YGN) Units 3 and 4 using modular accident analysis program (MAAP) 3.0B code. Three different severe accident scenarios, such as two loss of coolant accidents (LOCAs) and station blackout (SBO), were considered in this analysis. Results indicated that design parameters related to refueling water storage tank (RWST), accumulator and steam generator (S/G) have more dominant effects on the progression of severe accidents investigated, compared to the other six parameters. 9 refs., 5 tabs. (Author)

  8. Statistical analysis of extreme values for geomagnetic and geoelectric field variations for Canada

    Science.gov (United States)

    Nikitina, Lidia; Trichtchenko, Larisa; Boteler, David

    2016-04-01

    Disturbances of the geomagnetic field produced by space weather events cause variable geoelectric fields at Earth's surface which drive electric currents in power systems, resulting in hazardous impacts on electric power transmission. In extreme cases, as during the magnetic storm in March 13, 1989, this can result in burnt-out transformers and power blackouts. To make assessment of geomagnetic and geoelectric activity in Canada during extreme space weather events, extreme value statistical analysis has been applied to more than 40 years of magnetic data from the Canadian geomagnetic observatories network. This network has archived digital data recordings for observatories located in sub-auroral, auroral, and polar zones. Extreme value analysis was applied to hourly ranges of geomagnetic variations as an index of geomagnetic activity and to hourly maximum of rate-of-change of geomagnetic field. To estimate extreme geoelectric fields, the minute geomagnetic data were used together with Earth conductivity models for different Canadian locations to calculate geoelectric fields. The extreme value statistical analysis was applied to hourly maximum values of the horizontal geoelectric field. This assessment provided extreme values of geomagnetic and geoelectric activity which are expected to happen once per 50 years and once per 100 years. The results of this analysis are designed to be used to assess the geomagnetic hazard to power systems and help the power industry mitigate risks from extreme space weather events.

  9. Influence of Dust Loading on Atmospheric Ionizing Radiation on Mars

    Science.gov (United States)

    Norman, Ryan B.; Gronoff, Guillaume; Mertens, Christopher J.

    2014-01-01

    Measuring the radiation environment at the surface of Mars is the primary goal of the Radiation Assessment Detector on the NASA Mars Science Laboratory's Curiosity rover. One of the conditions that Curiosity will likely encounter is a dust storm. The objective of this paper is to compute the cosmic ray ionization in different conditions, including dust storms, as these various conditions are likely to be encountered by Curiosity at some point. In the present work, the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety model, recently modified for Mars, was used along with the Badhwar & O'Neill 2010 galactic cosmic ray model. In addition to galactic cosmic rays, five different solar energetic particle event spectra were considered. For all input radiation environments, radiation dose throughout the atmosphere and at the surface was investigated as a function of atmospheric dust loading. It is demonstrated that for galactic cosmic rays, the ionization depends strongly on the atmosphere profile. Moreover, it is shown that solar energetic particle events strongly increase the ionization throughout the atmosphere, including ground level, and can account for the radio blackout conditions observed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on the Mars Express spacecraft. These results demonstrate that the cosmic rays' influence on the Martian surface chemistry is strongly dependent on solar and atmospheric conditions that should be taken into account for future studies.

  10. Managing Current Complexity: Critical Energy Infrastructure Failures in North America

    Directory of Open Access Journals (Sweden)

    Colin MacDonald

    2012-04-01

    Full Text Available

    This paper applies the competing theories of High Reliability Organizations (HRO and Normal Accidents Theory (NAT, two competing views of risk management in highly-complex and tightly-coupled systems, in analyzing the 1998 Ice Storm and the 2003 Blackout to examine vulnerabilities in North America’s critical energy infrastructure (CEI. Inferences are then made by highlighting the similarities and differences in the two cases, which are then used to draw lessons for public managers regarding the protection of CEIs.

     

    As CEIs are highly-complex and tightly-coupled systems, failures stemming from complex and uncertain risks are inevitable. There is an increasingly low tolerance for failure in energy infrastructure because society’s critical infrastructures have become increasingly interdependent. Public managers must regulate CEIs in order to ensure an emphasis is placed on safety and security while also finding ways to reduce unnecessary complexities. It is through the adoption of such measures that public managers will aid in minimizing the cascading effects of inevitable failures.

     

  11. Influence of Modelling Options in RELAP5/SCDAPSIM and MAAP4 Computer Codes on Core Melt Progression and Reactor Pressure Vessel Integrity

    Directory of Open Access Journals (Sweden)

    Siniša Šadek

    2010-01-01

    Full Text Available RELAP5/SCDAPSIM and MAAP4 are two widely used severe accident computer codes for the integral analysis of the core and the reactor pressure vessel behaviour following the core degradation. The objective of the paper is the comparison of code results obtained by application of different modelling options and the evaluation of influence of thermal hydraulic behaviour of the plant on core damage progression. The analysed transient was postulated station blackout in NPP Krško with a leakage from reactor coolant pump seals. Two groups of calculations were performed where each group had a different break area and, thus, a different leakage rate. Analyses have shown that MAAP4 results were more sensitive to varying thermal hydraulic conditions in the primary system. User-defined parameters had to be carefully selected when the MAAP4 model was developed, in contrast to the RELAP5/SCDAPSIM model where those parameters did not have any significant impact on final results.

  12. Reliable Remote Relay Protection in Smart Grid

    Institute of Scientific and Technical Information of China (English)

    Jiapeng Zhang; Yingfei Dong

    2015-01-01

    As the false trips of remote protection relays are among the main reasons behind cascading blackouts, it is critical to design reli⁃able relay protection. Even though common protection schemes on traditional power systems have been investigated for a few de⁃cades, cascading failures in recent years indicate more research needed in this area. Consequently, researchers have proposed agent⁃based methods on the Smart Grid (SG) to address this issue. However, these existing agent⁃based methods simply use TCP protocol without considering real⁃time communication requirements (such as bandwidth and delay). To deal with this issue, several methods for efficient network resource management are proposed. Furthermore, these existing methods do not consider the poten⁃tial issues in practical communication networks, which may result in delay violation and trigger relay false trips. We have dis⁃cussed simple backup solutions in the previous work. In this paper, in addition to network efficiency, we focus on improving the system reliability by exploring known power system information and minimizing the chances of false trips of important remote re⁃lays, e.g., defining power line priorities based on their importance. Moreover, to further improve the system reliability, we also in⁃vestigate the peer⁃to⁃peer protection approaches to address the single point of failure of centralized control center.

  13. Geomagnetic Storms and Long-Term Impacts on Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kirkham, Harold; Makarov, Yuri V.; Dagle, Jeffery E.; DeSteese, John G.; Elizondo, Marcelo A.; Diao, Ruisheng

    2011-12-31

    Pacific Northwest National Laboratory was commissioned to study the potential impact of a severe GIC event on the western U.S.-Canada power grid (referred to as the Western Interconnection). The study identified long transmission lines (length exceeding 150 miles) that did not include series capacitors. The basic assumption for the study is that a GIC is more likely to couple to long transmission lines, and that series capacitors would block the flow of the induced DC GIC. Power system simulations were conducted to evaluate impacts to the bulk power system if transformers on either end of these lines failed. The study results indicated that the Western Interconnection was not substantially at risk to GIC because of the relatively small number of transmission lines that met this criterion. This report also provides a summary of the Hydro-Québec blackout on March 13, 1989, which was caused by a GIC. This case study delves into the failure mechanisms of that event, lessons learned, and preventive measures that have been implemented to minimize the likelihood of its reoccurrence. Finally, the report recommends that the electric power industry consider the adoption of new protective relaying approaches that will prevent severe GIC events from catastrophically damaging transformers. The resulting changes may increase the likelihood of smaller disruptions but should prevent an unlikely yet catastrophic national-level event.

  14. SPAR Model Structural Efficiencies

    Energy Technology Data Exchange (ETDEWEB)

    John Schroeder; Dan Henry

    2013-04-01

    The Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute (EPRI) are supporting initiatives aimed at improving the quality of probabilistic risk assessments (PRAs). Included in these initiatives are the resolution of key technical issues that are have been judged to have the most significant influence on the baseline core damage frequency of the NRC’s Standardized Plant Analysis Risk (SPAR) models and licensee PRA models. Previous work addressed issues associated with support system initiating event analysis and loss of off-site power/station blackout analysis. The key technical issues were: • Development of a standard methodology and implementation of support system initiating events • Treatment of loss of offsite power • Development of standard approach for emergency core cooling following containment failure Some of the related issues were not fully resolved. This project continues the effort to resolve outstanding issues. The work scope was intended to include substantial collaboration with EPRI; however, EPRI has had other higher priority initiatives to support. Therefore this project has addressed SPAR modeling issues. The issues addressed are • SPAR model transparency • Common cause failure modeling deficiencies and approaches • Ac and dc modeling deficiencies and approaches • Instrumentation and control system modeling deficiencies and approaches

  15. Distributed Monitoring for Prevention of Cascading Failures in Operational Power Grids

    CERN Document Server

    Warnier, Martijn; Koç, Yakup; Pauwels, Eric

    2015-01-01

    Electrical power grids are vulnerable to cascading failures that can lead to large blackouts. Detection and prevention of cascading failures in power grids is impor- tant. Currently, grid operators mainly monitor the state (loading level) of individual components in power grids. The complex architecture of power grids, with many interdependencies, makes it difficult to aggregate data provided by local compo- nents in a timely manner and meaningful way: monitoring the resilience with re- spect to cascading failures of an operational power grid is a challenge. This paper addresses this challenge. The main ideas behind the paper are that (i) a robustness metric based on both the topology and the operative state of the power grid can be used to quantify power grid robustness and (ii) a new proposed a distributed computation method with self-stabilizing properties can be used to achieving near real-time monitoring of the robustness of the power grid. Our con- tributions thus provide insight into the resilience wit...

  16. Shining India?: Assessing and addressing the risks from an unsustainable trajectory of climate, water, food, energy and income inequity

    Science.gov (United States)

    Lall, U.

    2012-12-01

    Climate and demographics are primary drivers of regional resource sustainability. In today's global economy, increasing trade has provided a mechanism to alleviate regional stresses. However, increasing regional income promotes consumption, aggravating regional and global resource pressures. South Asia, has the highest population density at a sub-continent scale. Given its monsoonal climate, and high intensity of agriculture it faces perhaps the most severe population weighted water stress in the world. Rapidly declining groundwater tables and the associated high energy use for pumping for irrigated agriculture translate into unsustainable energy imports and expenditure that contributed to the two largest blackouts in global history in summer 2012. Access to water has been progressively declining for both rural and urban populations for the last 3 decades. The increasing energy imports and poor grid reliability translate into limits to the growth of manufacturing and exports of goods and services. The growing income inequity within the population and across national borders, and the impacts of floods and droughts on access to water, food and energy collectively suggest a very high risk for social unrest and a conflict flashpoint. I present a scenario analysis that establishes this case for the emergence of internal and external strife in the region as an outcome of the current resource and natural disaster management policies in the region. Prospects for strategic policy changes for water and energy management and the design of a food procurement and distribution system that could lead to a better future are discussed.

  17. WECC Variable Generation Planning Reference Book: Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, Yuri V.; Du, Pengwei; Etingov, Pavel V.; Ma, Jian; Vyakaranam, Bharat

    2013-05-13

    The document titled “WECC Variable Generation Planning Reference Book”. This book is divided into two volumes; one is the main document (volume 1)and the other is appendices (volume 2). The main document is a collection of the best practices and the information regarding the application and impact of variables generation on power system planning. This volume (appendices) has additional information on the following topics: Probabilistic load flow problems. 2. Additional useful indices. 3. high-impact low-frequency (HILF) events. 4. Examples of wide-area nomograms. 5. Transmission line ratings, types of dynamic rating methods. 6. Relative costs per MW-km of different electric power transmission technologies. 7. Ultra-high voltage (UHV) transmission. 8.High voltage direct current (VSC-HVDC). 9. HVDC. 10. Rewiring of existing transmission lines. 11. High-temperature low sag (HTLS) conductors. 12. The direct method and energy functions for transient stability analysis in power systems. 13.Blackouts caused by voltage instability. 14. Algorithm for parameter continuation predictor-corrector methods. 15. Approximation techniques available for security regions. 16. Impacts of wind power on power system small signals stability. 17. FIDVR. 18. FACTS. 19. European planning standard and practices. 20. International experience in wind and solar energy sources. 21. Western Renewable Energy Zones (WREZ). 22. various energy storage technologies. 23. demand response. 24. BA consolidation and cooperation options. 25. generator power management requirements and 26. European planning guidelines.

  18. Power quality and availability: stakes and solutions; Qualite et disponibilite de l'electricite: enjeux et solutions

    Energy Technology Data Exchange (ETDEWEB)

    Hypolite, J.M.; Christin, J.F. [Schneider Electric, MGE UPS Systems, 95 - Argenteuil (France)

    2004-12-01

    Quality and availability of electric power are today strategic stakes for the overall economical sectors. A power outage can jeopardize the production of a company and generate considerable financial costs. The failure of a power installation can lead to a human risk, both for operators and users. The frequency of these malfunctions (black-outs and minor power cuts) is increasing and this trend should continue with the deregulation of the power markets, the increase of climatic risks and of the defects of electrical installations. Some solutions exist which allow to protect the infrastructures, the buildings and the processes against electrical faults. Their efficiency depends on a precise evaluation of the user's needs, on a relevant choice of products, on the preciseness of their implementation, on their periodical maintenance and on the control of their suitability with the evolutions of the installation. This booklet presents first the identified origins of failures: interconnection of power networks, climatic hazards, and improper electrical installations in buildings. The second part deals with the prevention of failure risks: criticality of the installation, identification of critical processes and real needs, choice, design, implementation, exploitation and maintenance of a proper technical solution. The third part treats of the right choice of equipments: inverters, automatic power source transfer system, and the last part summarizes the five masterpieces of resilience: auxiliary power set, inverter, harmonics compensator, power source transfer system and supervision system. (J.S.)

  19. I. Evaluation of the impact of alternative light technology on male broiler chicken growth, feed conversion, and allometric characteristics.

    Science.gov (United States)

    Rogers, Allison G; Pritchett, Elizabeth M; Alphin, Robert L; Brannick, Erin M; Benson, Eric R

    2015-03-01

    This study evaluates the impact of light-emitting diode (LED), cold cathode fluorescent (CCFL), and incandescent lamps on broiler performance. Male Ross 708 broilers (n=672) were raised to 6 wk age in 8 black-out modified large colony houses, under identical intermittent lighting conditions using 4 unique types of lamps, which were gradually dimmed throughout the study. Incandescent lamps served as the control; experimental technologies tested included CCFL and 2 different LED lamps. Each technology was tested in duplicate for each of 4 trials (8 replications total per technology) conducted across the course of one year to account for seasonal variance. Live performance for each technology was evaluated using live broiler body weight (BW), weight gain, feed conversion, and mortality. Birds were removed from each house at 7, 14, 35, and 42 d to be humanely euthanized, weighed, and necropsied for allometric tissue sample analysis. Relative to the technologies tested, results indicate that birds raised under incandescent lamps had significantly higher BW by 42 d, compared to birds raised under CCFL lamps, which had poorer BW performance (P=0.03). Birds raised under both LED technologies grew to final BWs similar to those raised under incandescent light, with significant differences in neither feed conversion nor mortality.

  20. Efeitos de um marcador temporal sobre respostas de escolha por maior atraso e magnitude do reforço em crianças

    Directory of Open Access Journals (Sweden)

    Tatiana Chagas Correia

    2015-06-01

    Full Text Available ResumoO presente experimento verificou se a apresentação de um marcador temporal durante o período de atraso do reforço aumentaria as respostas no componente com maior magnitude e atraso do reforço (autocontrole, diminuindo as escolhas pelo componente de menor atraso e magnitude (impulsividade, em um esquema concorrente. Três valores de atraso do reforço foram investigados. Participaram nove crianças distribuídas em três condições manipuladas no período de atraso do reforço: relógio, não-relógio e blackout. Escolhas entre o componente de autocontrole e impulsividade ocorriam na tela de computador sendo consequencia dos pontos trocados por brindes. Encontrou-se autocontrole na primeira apresentação dos menores valores de atraso no componente de maior atraso, mas não com valores maiores, independentemente da condição em vigor. O marcador temporal não indicou ser uma condição que aumente as respostas de autocontrole. Tais respostas estiveram relacionadas aos valores do atraso.

  1. Development of Sequential Calculating Type Autonomous Stabilizing Controller for Maintaining Transient Stability in case of Backup Relay Operation in Load System

    Science.gov (United States)

    Kobayashi, Ryoji; Maekawa, Kazuo; Shimomura, Kimihiko; Sasaki, Takashi; Kowada, Yasuyuki; Maeda, Toru

    A new Autonomous Stabilizing Controller (ASC) has been developed, which is based on the concept of using only locall information measured at the substation where ASC is installed. ASC prevents the power system from wide-area blackout by shedding generators optimally when a serious fault occurs in 154kV-or-below-voltage power system and is cleared by backup relay. ASC consists of three functions, a function of detecting faults and judging of starting stability calculations (The first function), a function of calculating power system stability (The second function), and a function of selecting optimal generators to be shed (The third function). The first function composes a signal for starting stability calculations when a fault cleared by backup relay is detected. According to the starting signal composed by the first function, the second function executes stability calculations based on equal area criterion. If the result of stability calculations is instable, the third function selects a generator to be shed by considering not only the stabilizing effect but also the quickly restoration after shedding. This paper presents total algorithms applied in ASC.

  2. Assessing Short-Term Voltage Stability of Electric Power Systems by a Hierarchical Intelligent System.

    Science.gov (United States)

    Xu, Yan; Zhang, Rui; Zhao, Junhua; Dong, Zhao Yang; Wang, Dianhui; Yang, Hongming; Wong, Kit Po

    2016-08-01

    In the smart grid paradigm, growing integration of large-scale intermittent renewable energies has introduced significant uncertainties to the operations of an electric power system. This makes real-time dynamic security assessment (DSA) a necessity to enable enhanced situational-awareness against the risk of blackouts. Conventional DSA methods are mainly based on the time-domain simulation, which are insufficiently fast and knowledge-poor. In recent years, the intelligent system (IS) strategy has been identified as a promising approach to facilitate real-time DSA. While previous works mainly concentrate on the rotor angle stability, this paper focuses on another yet increasingly important dynamic insecurity phenomenon-the short-term voltage instability, which involves fast and complex load dynamics. The problem is modeled as a classification subproblem for transient voltage collapse and a prediction subproblem for unacceptable dynamic voltage deviation. A hierarchical IS is developed to address the two subproblems sequentially. The IS is based on ensemble learning of random-weights neural networks and is implemented in an offline training, a real-time application, and an online updating pattern. The simulation results on the New England 39-bus system verify its superiority in both learning speed and accuracy over some state-of-the-art learning algorithms.

  3. Saturday 4 November 2006: Eole and/or E.ON fault?; Samedi 4 novembre 2006: la faute a Eole ou/et E.ON?

    Energy Technology Data Exchange (ETDEWEB)

    Poizat, F

    2006-12-15

    According to the UCTE (Union for the Coordination of Transmission of Electricity) Interim Report, it appears that the wind generators all over Europe suffered from the over-frequencies or under-frequencies resulting from the splitting of the European electricity transmission grid: besides 15 million customers being cut off from the electric supply, more than 10,000 MW, i.e. 60 % of the wind generation became un-operational. This made the production deficiency in Western Europe even worse, constraining the grid controllers to proceed with further load shedding in order to recover the situation. Moreover, as the classic production units were being stopped to reduce the excessive frequency, the wind generators in the Eastern zone began to reconnect automatically as the over-frequency was progressively being damped, complicating the task of the Central European dispatchers, at the risk of a complete collapse. Adding to the anarchic behavior of the wind generators is the suspicion that they contributed to the set of circumstances (human and organizational errors in particular) from which the black-out originated. This hypothesis rests on the poor accuracy of the production projections of a wind energy fleet as large as that of Germany (a power capacity reaching almost 20,000 MW)

  4. Dynamic instability of cooperation due to diverse activity patterns in evolutionary social dilemmas

    Science.gov (United States)

    Xia, Cheng-Yi; Meloni, Sandro; Perc, Matjaž; Moreno, Yamir

    2015-03-01

    Individuals might abstain from participating in an instance of an evolutionary game for various reasons, ranging from lack of interest to risk aversion. In order to understand the consequences of such diverse activity patterns on the evolution of cooperation, we study a weak prisoner's dilemma where each player's participation is probabilistic rather than certain. Players that do not participate get a null payoff and are unable to replicate. We show that inactivity introduces cascading failures of cooperation, which are particularly severe on scale-free networks with frequently inactive hubs. The drops in the fraction of cooperators are sudden, while the spatiotemporal reorganization of compact cooperative clusters, and thus the recovery, takes time. Nevertheless, if the activity of players is directly proportional to their degree, or if the interaction network is not strongly heterogeneous, the overall evolution of cooperation is not impaired. This is because inactivity negatively affects the potency of low-degree defectors, who are hence unable to utilize on their inherent evolutionary advantage. Between cascading failures, the fraction of cooperators is therefore higher than usual, which lastly balances out the asymmetric dynamic instabilities that emerge due to intermittent blackouts of cooperative hubs.

  5. SAMPSON Parallel Computation for Sensitivity Analysis of TEPCO's Fukushima Daiichi Nuclear Power Plant Accident

    Science.gov (United States)

    Pellegrini, M.; Bautista Gomez, L.; Maruyama, N.; Naitoh, M.; Matsuoka, S.; Cappello, F.

    2014-06-01

    On March 11th 2011 a high magnitude earthquake and consequent tsunami struck the east coast of Japan, resulting in a nuclear accident unprecedented in time and extents. After scram started at all power stations affected by the earthquake, diesel generators began operation as designed until tsunami waves reached the power plants located on the east coast. This had a catastrophic impact on the availability of plant safety systems at TEPCO's Fukushima Daiichi, leading to the condition of station black-out from unit 1 to 3. In this article the accident scenario is studied with the SAMPSON code. SAMPSON is a severe accident computer code composed of hierarchical modules to account for the diverse physics involved in the various phases of the accident evolution. A preliminary parallelization analysis of the code was performed using state-of-the-art tools and we demonstrate how this work can be beneficial to the nuclear safety analysis. This paper shows that inter-module parallelization can reduce the time to solution by more than 20%. Furthermore, the parallel code was applied to a sensitivity study for the alternative water injection into TEPCO's Fukushima Daiichi unit 3. Results show that the core melting progression is extremely sensitive to the amount and timing of water injection, resulting in a high probability of partial core melting for unit 3.

  6. Trauma, memory, testimony: phenomenological, psychological, and ethical perspectives

    Directory of Open Access Journals (Sweden)

    Claudia Welz

    2016-01-01

    Full Text Available How can severely traumatized persons re-present the past and its impact on the present if (due to blackout, repression, or dissociation they could not witness what they went through, or can hardly recall it? Drawing on Holocaust testimonies, this article explores the crisis of witnessing constituted by the Shoah and, more generally, problems of integrating and communicating traumatic experiences. Phenomenological, psychological, and ethical perspectives contribute to a systematic investigation of the relation between trauma, memory and testimony. I will argue that preserving personal continuity across the gap between past and present presupposes not only an ‘inner witness’ – which can, according to a long philosophical tradition, be identified with a person’s conscience – but also a social context in which one is addressed and can respond. An attentive listener can bear witness to the witness by accepting the assignation of responsibility implied in testimonial interaction, and thereby support the dialogic restitution of memory and identity.

  7. Inspirations of Fukushima Daiichi Nuclear Accident and the Safety Improvement of Domestic NPPs in Operation%我国运行核电机组安全改进措施分析

    Institute of Scientific and Technical Information of China (English)

    薛长江; 洪源平; 尹峰; 戴恒才; 陈其荣; 操丰

    2015-01-01

    为了全面提高我国运行核电厂安全性和应对超设计基准事故能力,文章根据福岛核事故中长期断电、堆芯熔毁、乏燃料池破损、厂房被淹等原因分析结果,结合了国家核安全局整改要求和国内运行核电整改进展,总结了包括完善严重事故导则、增加一回路和二回路应急补水、防水封堵、增加移动电源和非能动消氢复合器等改进措施及其技术要点.%In order to improve the operation safety and the abilities to deal with beyond design basis accidents of the domestic nuclear power plants in operation, this article summarized some improvement methods and their technical requirements, including modification of severe accident guidelines, arrangement of emergency water makeup of the main coolant loop and the secondary loop, waterproof capping, arrangement of movable power supply and passive hydrogen recombiner, according to reason analyses for long-term blackout, core meltdown, spent fuel pool failure, important building submergence and the improvement requirements put forward by the National Nuclear Safety Administration,.

  8. A multiobjective optimization approach to the operation and investment of the national energy and transportation systems

    Science.gov (United States)

    Ibanez, Eduardo

    Most U.S. energy usage is for electricity production and vehicle transportation, two interdependent infrastructures. The strength and number of the interdependencies will increase rapidly as hybrid electric transportation systems, including plug-in hybrid electric vehicles and hybrid electric trains, become more prominent. There are several new energy supply technologies reaching maturity, accelerated by public concern over global warming. The National Energy and Transportation Planning Tool (NETPLAN) is the implementation of the long-term investment and operation model for the transportation and energy networks. An evolutionary approach with underlying fast linear optimization are in place to determine the solutions with the best investment portfolios in terms of cost, resiliency and sustainability, i.e., the solutions that form the Pareto front. The popular NSGA-II algorithm is used as the base for the multiobjective optimization and metrics are developed for to evaluate the energy and transportation portfolios. An integrating approach to resiliency is presented, allowing the evaluation of high-consequence events, like hurricanes or widespread blackouts. A scheme to parallelize the multiobjective solver is presented, along with a decomposition method for the cost minimization program. The modular and data-driven design of the software is presented. The modeling tool is applied in a numerical example to optimize the national investment in energy and transportation in the next 40 years.

  9. Differences in Climbing Ability of Cimex lectularius and Cimex hemipterus (Hemiptera: Cimicidae).

    Science.gov (United States)

    Kim, Dae-Yun; Billen, Johan; Doggett, Stephen L; Lee, Chow-Yang

    2017-03-15

    The climbing abilities of two bed bug species, Cimex lectularius L. and Cimex hemipterus (F.), were determined by evaluating their escape rates from smooth surface pitfall traps using four commercial bed bug monitors (Verifi Bed Bug Detector, ClimbUp Insect Interceptor, BlackOut Bed Bug Detector, and SenSci Volcano Bed Bug Detector). All detectors were used in the absence of lures or attractants. Unlike C. lectularius, adult C. hemipterus were able to escape from all traps. On the other hand, no or a low number nymphs of both species escaped, depending on the evaluated traps. Examination of the vertical friction force of adults of both species revealed a higher vertical friction force in C. hemipterus than in C. lectularius. Scanning electron microscope micrograph observation on the tibial pad of adult bed bugs of C. hemipterus showed the presence of a greater number of tenent hairs on the tibial pad than on that of adult C. lectularius. No tibial pad was found on the fourth and fifth instars of both species. Near the base of the hollow tenent hairs is a glandular epithelium that is better developed in adult C. hemipterus than in adult C. lectularius. This study highlights significant morphological differences between C. lectularius and C. hemipterus, which may have implications in the monitoring and management of bed bug infestations.

  10. Preliminary Test of a small heat pipe for hybrid control rod in-core passive decay heat removal system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Guk; Ban, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2014-05-15

    This paper introduces 'Hybrid control rod' combining its original function and heat removal ability. The high temperature operation and high resistance of radiation should be considered to adopt the hybrid heat pipe at the in-core condition. Other design consideration is to make extra inlet parts because it has a high risk of inlet boundary failure. It means that the introduction of heat pipe system is difficult to present nuclear power plants. The other concepts are presented to out-core cooling design but it has low performance compared with in-core heat removal system. Hybrid heat pipe for in-core heat removal system suggests the solution of these problems. Ultimate objective of this research is to develop the passive emergency decay heat removal system using hybrid heat pipes targeting design bases accidents such as station black-out (SBO) and small break loss of coolant accident (SBLOCA). The purpose of this work is to confirm the performance and heat transfer behavior of hybrid heat pipe. The hybrid heat pipe has special condition for operation. Therefore, it is hard to analyze their behavior in core. Table I shows the characteristics of hybrid heat pipe and consideration for manufacturing the heat pipe.

  11. Context-Independent Centrality Measures Underestimate the Vulnerability of Power Grids

    CERN Document Server

    Verma, Trivik; Kooij, Robert E

    2013-01-01

    Power grids vulnerability is a key issue in society. A component failure may trigger cascades of failures across the grid and lead to a large blackout. Complex network approaches have shown a direction to study some of the problems faced by power grids. Within Complex Network Analysis structural vulnerabilities of power grids have been studied mostly using purely topological approaches, which assumes that flow of power is dictated by shortest paths. However, this fails to capture the real flow characteristics of power grids. We have proposed a flow redistribution mechanism that closely mimics the flow in power grids using the PTDF. With this mechanism we enhance existing cascading failure models to study the vulnerability of power grids. We apply the model to the European high-voltage grid to carry out a comparative study for a number of centrality measures. `Centrality' gives an indication of the criticality of network components. Our model offers a way to find those centrality measures that give the best in...

  12. THERMAL HYDRAULIC ISSUES OF CONTAINMENT FILTERED VENTING SYSTEM FOR A LONG OPERATING TIME

    Directory of Open Access Journals (Sweden)

    YOUNG SU NA

    2014-12-01

    Full Text Available This study investigated the thermal hydraulic issues in the Containment Filtered Venting System (CFVS for a long operating time using the MELCOR computer code. The modeling of the CFVS, including the models for pool scrubbing and the filter, was added to the input file for the OPR-1000, and a Station Blackout (SBO was chosen as an accident scenario. Although depressurization in the containment building as a primary objective of the CFVS was successful, the decontamination feature by scrubbing and filtering in the CFVS for a long operating time could fail by the continuous evaporation of the scrubbing solution. After the operation of the CFVS, the atmosphere temperature in the CFVS became slightly above the water saturation temperature owing to the release of an amount of steam with high temperature from the containment building to the scrubbing solution. Reduced pipe diameters at the inlet and outlet of the CFVS vessel mitigated the evaporation of scrubbing water by controlling the amount of high-temperature steam and the water saturation temperature.

  13. Student Nurse in the War Zone.

    Science.gov (United States)

    2016-12-01

    : Editor's note: From its first issue in 1900 through to the present day, AJN has unparalleled archives detailing nurses' work and lives over more than a century. These articles not only chronicle nursing's growth as a profession within the context of the events of the day, but they also reveal prevailing societal attitudes about women, health care, and human rights. Today's nursing school curricula rarely include nursing's history, but it's a history worth knowing. To this end, From the AJN Archives highlights articles selected to fit today's topics and times.In this month's article, from the September 1942 issue, senior nursing student Frances Carr writes vividly about life and work in Honolulu after Pearl Harbor. "Students… have had seared into their memories scenes of such horror as cannot be imagined…. When night fell, the nursing staff faced its first test of caring for hundreds of patients in a blackout that had to be absolute." And in this issue, see "Remembering Pearl Harbor at 75 Years," which tells the stories of five nurses from the Army and Navy Nurse Corps who were stationed nearby at the time of the attack.

  14. The impact of a natural disaster on altruistic behaviour and crime.

    Science.gov (United States)

    Lemieux, Frederic

    2014-07-01

    Institutional altruism in the form of a public-sector intervention and support for victims and social altruism generated by mutual aid and solidarity among citizens constitute a coming together in a crisis. This coming together and mutual support precipitate a decrease in crime rates during such an event. This paper presents an analysis of daily fluctuations in crime during the prolonged ice storms in Quebec, Canada, in January 1998 that provoked an electrical blackout. Of particular interest are the principal crisis-related influences on daily crime patterns. A first series of analyses examines the impact of altruistic public-sector mobilisation on crime. A significant decline in property crime rates was noticed when cheques were distributed to crisis victims in financial need in Montérégie, and hence they were attributable to public intervention (institutional altruism). Moreover, the rate of social altruism (financial donations), which was more substantial in adjoining rather than distant regions, was inversely proportional to crime rates.

  15. Power Adaptive Data Encryption for Energy-Efficient and Secure Communication in Solar-Powered Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jong Min Kim

    2016-01-01

    Full Text Available Basic security of data transmission in battery-powered wireless sensor networks (WSNs is typically achieved by symmetric-key encryption, which uses little energy; but solar-powered WSNs sometimes have sufficient energy to achieve a higher level of security through public-key encryption. However, if energy input and usage are not balanced, nodes may black out. By switching between symmetric-key and public-key encryption, based on an energy threshold, the level of security can be traded off against the urgency of energy-saving. This policy can also reduce the amount of energy used by some nodes in a WSN, since data encrypted using a public-key is simply relayed by intermediate nodes, whereas data encrypted using a symmetric-key must be decrypted and reencrypted in every node on its path. Through a simulation, we compared the use of either symmetric-key or public-key encryption alone with our scheme, which was shown to be more secure, to use energy more effectively, and to reduce the occurrence of node blackouts.

  16. Assessment of control strategies for fault ride through of SCIG-based wind energy conversion systems

    Directory of Open Access Journals (Sweden)

    Manaullah

    2016-01-01

    Full Text Available With increasing penetration of wind energy into the power grid, researchers have started focusing more on control and coordination of wind energy conversion systems (WECS with the other components at system level, especially during fault. It is important to implement a suitable fault ride through control strategy to avoid tripping of the generators when the power system is subjected to voltage dips normally below 90% of nominal voltage. The dips below 90% may lead to a significant loss of generation and frequency collapse, followed by a blackout. This article implements and assesses the methodologies to deal with such situations for squirrel cage induction generator-based wind energy conversion systems employing fully rated power electronic converters. Three distinct control techniques—namely, balanced positive sequence control, positive negative sequence control, and dual current control—have been simulated and applied to grid side converter of SCIG-based WECS. The performance of all the three control strategies has been compared and presented in this work. During this study, the system is subjected to the most common unsymmetrical line to ground (LG fault and most severe symmetrical LLL fault on grid for the purpose of anaysis.

  17. Glaze Icing on Superhydrophobic Coating Prepared by Nanoparticles Filling Combined with Etching Method for Insulators

    Directory of Open Access Journals (Sweden)

    Chao Guo

    2015-01-01

    Full Text Available Icing on insulators may cause flashover or even blackout accidents in the power transmission system. However, there are few anti-icing techniques for insulators which consume energy or manpower. Considering the water repelling property, the superhydrophobic surface is introduced for anti-icing of insulators. Among the icing forms, the glaze icing owns the highest density, strongest adhesion, and greatest risk to the power transmission system but lacks researches on superhydrophobic surface. In this paper, superhydrophobic surfaces with contact angle of 166.4°, contact angle hysteresis of 0.9°, and sliding angle of less than 1° are prepared by nanoparticle filling combined with etching method. The coated glass slide and glass insulator showed excellent anti-icing performance in the glaze icing test at −5°C. The superhydrophobicity and anti-icing property of the coatings benefit from the low surface energy and hierarchical rough structure containing micron scale pits and nanoscale coralloid bulges supported by scanning electron microscopy (SEM, atomic force microscopy (AFM, and X-ray photoelectron spectroscopy (XPS characterization.

  18. Mixtures of biofuels can serve as an ecological substitute for photovoltaics during nighttime hours

    Energy Technology Data Exchange (ETDEWEB)

    Matejovsky, Vladimir [QMS Consulting, Prague (Czech Republic); Hromadko, Jan; Hoenig, Vladimir [Czech Univ. of Life Sciences, Prague (Czech Republic)

    2013-06-01

    Diesel fuels consisting of mixtures of ethanol (alternatively butanol), FAME and vegetable oils in variable proportions can meet different requirements of OEMs for viscosity and heating values and constitute a form of renewable and storable energy from the sun which can be easily transformed into electricity. The ratio of component can vary according to the immediate availability and prices of components, oxygen content and the absence of aromatic hydrocarbons enabling the combustion of these mixtures in engines with very low emissions, especially of particulates. From these reasons these mixtures constitute an ecological source of energy suitable to supplement photovoltaic power plants during the night, when insufficient electric power supply and even blackouts can occur. It was verified that Diesel engines working with a mixture consisting of 50% ethanol, 30% FAME, 20% rapeseed oil and a small dosage of cetane improver, exuded much less smoke compared with B7 and B30 fuels and only little more when compared with the E95 fuel for which smoke emission ions was almost zero. Similar results were obtained when ethanol was replaced by biobutanol. (orig.)

  19. Answer to the dynamic (fretting effect) and static (oxide) behavior of electric contact surfaces: based on a five-year infrared thermographic study

    Science.gov (United States)

    Paez-Leon, Cristobal D.; Patino, Antonio R.; Aguillon, Luis

    1991-03-01

    This paper describes the results of a five-year study carried out in 38 power substations (230, 115, 34.5 and 13.8 Kv), located in the Western power electric system of CADAFE (Venezuela's national Electric Utility). A total of 154 hot spots were found between 1980 and 1982, a time span considered a reliable source of information in connection with methodology, term and results. The distribution of hot spots found during those years was 77, 33 and 44. The reduction of the spot/substation parameter was found to be 4.1, 3.3 and 3.1, respectively. Every item detected could have been the cause of major interruptions, locally and regionally, or even the system's blackout. The methodology used to determine the major concentration of findings and their location on the equipment, followed the sequence of Pareto's Diagram and Ishikawa's Graphic. Based on the results of the study whose results are presented here, a lubricant and compound-aid connector for Al-Al and bimetallic electric connections was formulated, developed, manufactured, tested (at IREQ laboratories) and traded (CONECTECH CAC- 01). To date, the whole process represents 12 years of work. The connector's behavior and reliability are being tested throughout Venezuela's national electric system (responsible for the supply of around 50,000 Gwh/year) with the use of 12 Tons of CONECTECH CAC-01.

  20. Evaluation of passive autocatalytic recombiners (PARS) performance for a PWR-konvoi containment type with Gothic 8.1 code; Evaluacion de la implementacion de recombinadores autocataliticos pasivos (PAR) en una contencion tipo Konvoi con el codigo Gothic 8.1

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Alonso Conty, E.; Papini, D.; Jimenez Varas, G.

    2016-08-01

    The study presented in this work analyses the evaluation of Passive Autocatalytic Recombiners (PARs) performance for a PWR-Konvoi containment type as a result of an international collaboration between the Paul Scherrer institute (PSI) and the Universidad Politecnica de Madrid (UPM). The implementation study analyzes the size, location and number of the PARs to minimize the risk arising from a hydrogen release and its distribution in the containment building during a hypothetical severe accident. A detailed 3D model of containment was used for the simulations developed for the Gothic 8.1 code. In the first place, the hydrogen preferential pathways and points of hydrogen accumulation were studies and identified starting from the base case scenario without any mitigation measure. The severe accident scenario chosen is a fast release of hydrogen-steam mixture from hot leg creep rupture during SBO (Station Black-Out) accident. Secondly a configuration of PARs was simulated under the same conditions of the unmitigated case. The PAR configuration offered an improvement in the chosen accident scenario, decreasing the hydrogen concentration values below the flammability limit /hydrogen concentration below 7%) in all the containment compartments. (Author)

  1. The effects of synthetic cannabinoid UR-144 on the human body-A review of 39 cases.

    Science.gov (United States)

    Adamowicz, Piotr; Gieroń, Joanna; Gil, Dominika; Lechowicz, Wojciech; Skulska, Agnieszka; Tokarczyk, Bogdan

    2017-03-07

    UR-144 [(1-pentyl-1H-indol-3-yl)(2,2,3,3-tetramethylcyclopropyl)methanone] is a synthetic cannabinoid, which has been detected in many 'legal highs', seized from the global drug market since the beginning of 2012. It has gained popularity as a 'legal' alternative to classic cannabis in countries where it was not controlled. Despite the widespread distribution of this substance, the data on its effects on the human body are scarce. Therefore, this paper describes the results of analysis and observed effects in 39 cases in which UR-144 was determined in blood. Symptoms were noted from the blood sampling forms filled out by the representative doctor. The determined concentrations of UR-144 were in the range of trace amounts (LOD-0.15ng/mL; LOQ-0.5ng/mL) up to 17ng/mL. The most common observed effects included slurred speech, dilated pupils, sluggish and abnormal pupillary reaction, cheerful behaviour, poor coordination, and staggering. Less frequently observed were: verbosity, narrow pupils, loss of consciousness, pale or reddened facial skin, blackout, euphoria, agitation, hallucinations, hindered communication, shaking hands, seizures, convulsions, somnolence, delayed movements, redness of the conjunctiva, and tachycardia. The discussed cases show the effects observed after UR-144 use. This study can assist in the recognition of possible effects caused by this substance.

  2. Integrated DEA Models and Grey System Theory to Evaluate Past-to-Future Performance: A Case of Indian Electricity Industry

    Directory of Open Access Journals (Sweden)

    Chia-Nan Wang

    2015-01-01

    Full Text Available The growth of economy and population together with the higher demand in energy has created many concerns for the Indian electricity industry whose capacity is at 211 gigawatts mostly in coal-fired plants. Due to insufficient fuel supply, India suffers from a shortage of electricity generation, leading to rolling blackouts; thus, performance evaluation and ranking the industry turn into significant issues. By this study, we expect to evaluate the rankings of these companies under control of the Ministry of Power. Also, this research would like to test if there are any significant differences between the two DEA models: Malmquist nonradial and Malmquist radial. Then, one advance model of MPI would be chosen to see these companies’ performance in recent years and next few years by using forecasting results of Grey system theory. Totally, the realistic data 14 are considered to be in this evaluation after the strict selection from the whole industry. The results found that all companies have not shown many abrupt changes on their scores, and it is always not consistently good or consistently standing out, which demonstrated the high applicable usability of the integrated methods. This integrated numerical research gives a better “past-present-future” insights into performance evaluation in Indian electricity industry.

  3. Integrated DEA models and grey system theory to evaluate past-to-future performance: a case of Indian electricity industry.

    Science.gov (United States)

    Wang, Chia-Nan; Nguyen, Nhu-Ty; Tran, Thanh-Tuyen

    2015-01-01

    The growth of economy and population together with the higher demand in energy has created many concerns for the Indian electricity industry whose capacity is at 211 gigawatts mostly in coal-fired plants. Due to insufficient fuel supply, India suffers from a shortage of electricity generation, leading to rolling blackouts; thus, performance evaluation and ranking the industry turn into significant issues. By this study, we expect to evaluate the rankings of these companies under control of the Ministry of Power. Also, this research would like to test if there are any significant differences between the two DEA models: Malmquist nonradial and Malmquist radial. Then, one advance model of MPI would be chosen to see these companies' performance in recent years and next few years by using forecasting results of Grey system theory. Totally, the realistic data 14 are considered to be in this evaluation after the strict selection from the whole industry. The results found that all companies have not shown many abrupt changes on their scores, and it is always not consistently good or consistently standing out, which demonstrated the high applicable usability of the integrated methods. This integrated numerical research gives a better "past-present-future" insights into performance evaluation in Indian electricity industry.

  4. Analysis of core damage frequency: Peach Bottom, Unit 2 internal events appendices

    Energy Technology Data Exchange (ETDEWEB)

    Kolaczkowski, A.M.; Cramond, W.R.; Sype, T.T.; Maloney, K.J.; Wheeler, T.A.; Daniel, S.L. (Science Applications International Corp., Albuquerque, NM (USA); Sandia National Labs., Albuquerque, NM (USA))

    1989-08-01

    This document contains the appendices for the accident sequence analysis of internally initiated events for the Peach Bottom, Unit 2 Nuclear Power Plant. This is one of the five plant analyses conducted as part of the NUREG-1150 effort for the Nuclear Regulatory Commission. The work performed and described here is an extensive reanalysis of that published in October 1986 as NUREG/CR-4550, Volume 4. It addresses comments from numerous reviewers and significant changes to the plant systems and procedures made since the first report. The uncertainty analysis and presentation of results are also much improved, and considerable effort was expended on an improved analysis of loss of offsite power. The content and detail of this report is directed toward PRA practitioners who need to know how the work was done and the details for use in further studies. The mean core damage frequency is 4.5E-6 with 5% and 95% uncertainty bounds of 3.5E-7 and 1.3E-5, respectively. Station blackout type accidents (loss of all ac power) contributed about 46% of the core damage frequency with Anticipated Transient Without Scram (ATWS) accidents contributing another 42%. The numerical results are driven by loss of offsite power, transients with the power conversion system initially available operator errors, and mechanical failure to scram. 13 refs., 345 figs., 171 tabs.

  5. Correlation of Steam Generator Mixing Parameters for Severe Accident Hot-Leg Natural Circulation

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Yehong; Guentay, Salih [Paul Scherrer Institut, Villigen PSI, CH-5232 (Switzerland)

    2008-07-01

    Steam generator inlet plenum mixing phenomenon with hot-leg counter-current natural circulation during a PWR station blackout severe accident is one of the important processes governing which component will fail first as a result of thermal challenge from the circulating gas with high temperature and pressure. Since steam generator tube failure represents bypass release of fission product from the reactor to environment, study of inlet plenum mixing parameters is important to risk analysis. Probability distribution functions of individual mixing parameter should be obtained from experiments or calculated by analysis. In order to perform sensitivity studies of the synergetic effects of all mixing parameters on the severe accident-induced steam generator tube failure, the distribution and correlation of these mixing parameters must be known to remove undue conservatism in thermal-hydraulic calculations. This paper discusses physical laws governing three mixing parameters in a steady state and setups the correlation among these mixing parameters. The correlation is then applied to obtain the distribution of one of the mixing parameters that has not been given in the previous CFD analysis. Using the distributions and considering the inter-dependence of the three mixing parameters, three sensitivity cases enveloping the mixing parameter uncertainties are recommended for the plant analysis. (authors)

  6. TOPOLOGY AND CASCADING LINE OUTAGES IN POWER GRIDS

    Institute of Scientific and Technical Information of China (English)

    David L. PEPYNE

    2007-01-01

    Motivated by the small world network research of Watts & Strogatz, this paper studies relationships between topology and cascading line outages in electric power grids. Cascading line outages are a type of cascading collapse that can occur in power grids when the transmission network is congested. It is characterized by a self-sustaining sequence of line outages followed by grid breakup, which generally leads to widespread blackout. The main findings of this work are twofold: On one hand, the work suggests that topologies with more disorder in their interconnection topology tend to be robust with respect to cascading line outages in the sense of being able to support greater generation and demand levels than more regularly interconnected topologies. On the other hand, the work suggests that topologies with more disorder tend to be more fragile in that should a cascade get started, they tend to break apart after fewer outages than more regularly interconnected topologies. Thus, as has been observed in other complex networks, there appears to be a tradeoff between robustness and fragility.These results were established using synthetically generated power grid topologies and verified using the IEEE 57 bus and 188 bus power grid test cases.

  7. [Responding to patients with home mechanical ventilation after the Great East Japan Earthquake and during the planned power outages. How should we be prepared for a future disaster ?].

    Science.gov (United States)

    Takechi, Yukako

    2011-12-01

    The unprecedented earthquake(magnitude-9 in the Japanese seismic intensity scale)hit off the east coast of Japan on March 11, 2011. Consequently, there were planned power outages in the area nearby Tokyo to avoid massive blackouts caused by a stoppage of Fukushima nuclear plants.Our clinic located in Kawasaki city was also hit by the earthquake(magnitude- 5).During the period of two months(March and April 2011), we had a total of 52 patients with home respiratory care (5-TPPV, 11-NPPV and 36-HOT)at that time.Two out of three 24 hour-TPPV users had no external battery.After the earthquake, there was a 7-hour electricity failure in some areas, and a patient with ASV(adaptive servo ventilator)was living there.Moreover, 3-hour/day power outages were carried out from March 14 to March 28, affecting people's everyday lives. However, the patient had no harmful influences from the power failure because a ventilation company lent us an external battery(4-9 hour life capacity)for the patients, and we were able to avoid an emergency situation caused by the power failure.In conclusion, we ought to be prepared for patients with home mechanical ventilation in the future toward unforeseen large scale power outages.

  8. Identification of Optimal Path in Power System Network Using Bellman Ford Algorithm

    Directory of Open Access Journals (Sweden)

    S. Hemalatha

    2012-01-01

    Full Text Available Power system network can undergo outages during which there may be a partial or total blackout in the system. In that condition, transmission of power through the optimal path is an important problem in the process of reconfiguration of power system components. For a given set of generation, load pair, there could be many possible paths to transmit the power. The optimal path needs to consider the shortest path (minimum losses, capacity of the transmission line, voltage stability, priority of loads, and power balance between the generation and demand. In this paper, the Bellman Ford Algorithm (BFA is applied to find out the optimal path and also the several alternative paths by considering all the constraints. In order to demonstrate the capability of BFA, it has been applied to a practical 230 kV network. This restorative path search guidance tool is quite efficient in finding the optimal and also the alternate paths for transmitting the power from a generating station to demand.

  9. 试分析配电自动化对配网不停电作业安全的影响%Analysis on the Influence of Power Distribution Automation to the Security of Distribution Network Non Outage Operation

    Institute of Scientific and Technical Information of China (English)

    隗笑; 侯莉媛; 高永强

    2016-01-01

    Blackout overhaul will be larger effects on the user's normal power, no power outage maintenance is a kind of effective measures to keep the power supply is normal, in order to guarantee the safety of no power operation, need to introduce distribution automation technology. Based on the actual project as an example of the power distribution between the characteristics were analyzed, and then the optimized retroift scheme of the distribution network was introduced. Finally, the distribution automation of distribution network power outage operation safety effect were analyzed.%停电检修会对用户的正常用电造成比较大的影响,不停电检修是一种保持供电正常的有效措施,为了保证不停电作业的安全性,需要积极引入配电自动化技术。文章以实际工程为例对配电带电作业特点进行了分析,然后介绍了配电网的优化改造方案,最后对配电自动化对配网不停电作业安全影响进行了分析。

  10. Controllability Analysis for Operation Margin of Zone 3 Impedance Relay

    Science.gov (United States)

    Li, Shenghu; Yorino, Naoto; Zoka, Yoshifumi

    Undesirable operation of zone 3 impedance relay (mho relays) is a possible factor for causing cascading failure as seen in several previous large scale blackouts, where power flow redistribution and power swing caused by outage or switching operations satisfy the condition for the relay operation. So far, the condition itself has not fully been investigated, and therefore, there has been little attempt to avoid the relay operation by means of direct power flow control. This paper analyzes the condition for zone 3 relay operation from the viewpoint of its sensitivity to power flow. An operating margin for security is defined for each relay to carry out effective monitoring. It is newly pointed out that undesirable operation can be effectively avoided by reactive power controls as well as real power controls. The method to compute the operation margin is also given through the analysis of the optimal Var location to control the operation margin. Effectiveness of the proposed method is demonstrated using the IEEE test systems.

  11. The effects of geomagnetic disturbances on electrical systems at the earth's surface

    Science.gov (United States)

    Boteler, D. H.; Pirjola, R. J.; Nevanlinna, H.

    Geomagnetic disturbances have affected electrical systems on the ground for over 150 years. The first effects were noted on the early telegraph in the 1840s and in this century magnetic storms have caused power system blackouts and phone system outages. Affected systems include all those that use electrical conductors: whether for transmission of power or signals or where the conducting properties are incidental to their use such as with pipelines and railway tracks. In power systems geomagnetically induced currents cause partial saturation of power transformers producing transformer heating and distortion of the ac waveform leading to misoperation of relays and other equipment. On pipelines, induced currents may contribute to corrosion but also present a problem with the electrical surveys of the pipe performed to monitor the corrosion prevention systems. Severity of these effects depends on disturbance size, proximity to the auroral zone, and the conductivity structure of the Earth. Also significant are system parameters such as the use of higher resistance coatings on pipelines and the linking of power systems into larger networks. In this paper we have attempted to catalogue all the published reports of geomagnetic effects on electrical systems and show their occurrence in the context of the solar cycle and geomagnetic activity variations for the years 1844 to 1996.

  12. 配电网可靠性影响因素分析与提升措施探讨%Factors affecting of distribution network reliability and its promotion measures

    Institute of Scientific and Technical Information of China (English)

    王浩浩

    2014-01-01

    Statistical analysis of the impact on the level of distribution network reliability insufficient system power brownouts, blackouts, and scheduled outage. In response to these factors, citing reduced outage frequency and timing of various measures, so as to improve the level of distribution network reliability purposes. These measures on the power supply enterprise have certain practical reference value.%统计分析出影响配电网可靠性水平的系统电源不足限电、故障停电以及预安排停电等因素的具体原因。针对这些影响因素,列举了减少各类停电次数及时间的措施,从而达到改善配电网可靠性水平的目的。这些措施对供电企业具有一定的现实参考意义。

  13. Coordination learning in stag hunt games with application to emergency management.

    Science.gov (United States)

    Guastello, Stephen J; Bond Jr, Robert W

    2004-07-01

    Response teams for natural disaster emergencies require coordinated and self-organized efforts for rescue, medical services, damage containment, and evacuation. The unfolding of events depends on initial conditions of specific time, location, and preparedness of the response teams. This study considered a new range of emergency response situations where the perpetrator is a sentient attacker that learns with repeated exchanges. The strategy is conceptualized as a stag hunt coordination game on the part of the defense agents and a strictly competitive game with respect to the attacking adversary. Participants were 28 university students who played an iterative board game (The Creature that Ate Sheboygan) wherein a team of three Humans represented military and civil resources, against one Godzilla-type monster. The Monster gained points by destroying buildings and human combat power. The Humans gained points by wearing down the Monster's defenses and containing damage caused by the Monster. Experimental manipulations and empirical analysis showed the following: Communication outages among the Humans assisted the Monster, but the ability to communicate only equalized the Humans' chances rather than providing them with an advantage. Coordination among Humans was instant, but it fluctuated greatly as a result of the Monster's progress. Nonlinear analysis showed an asymptotic decline in coordination to a non-zero level in response to outcome uncertainty. Learning effects were noted for Humans and Monsters, but there were significant interactions with communication blackout conditions

  14. Voltage stability analysis of grid-connected wind farms with FACTS: Static and dynamic analysis

    Directory of Open Access Journals (Sweden)

    Kevin Zibran Heetun

    2016-01-01

    Full Text Available Recently, analysis of some major blackouts and failures of power system shows that voltage instability problem has been one of the main reasons of these disturbances and network collapses. In this article, a systematic approach to voltage stability analysis using various techniques for the IEEE 14-bus case study is presented. Static analysis is used to analyze the voltage stability of the system under study, while the dynamic analysis is used to evaluate the performance of compensators. The static techniques used are power flow, V–P curve analysis, and Q–V modal analysis. In this study, Flexible Alternating Current Transmission system (FACTS devices—namely, static synchronous compensators (STATCOMs and static var compensators (SVCs—are used as reactive power compensators, taking into account maintaining the violated voltage magnitudes of the weak buses within the acceptable limits defined in ANSI C84.1. Simulation results validate that both the STATCOMs and the SVCs can be effectively used to enhance the static voltage stability and increasing network loadability margin. Additionally, based on the dynamic analysis results, it has been shown that STATCOMs have superior performance, in dynamic voltage stability enhancement, compared to SVCs.

  15. The back-story on FlashForward

    CERN Multimedia

    2009-01-01

    Micro black holes that consume the world, strangelets that trigger a runaway reaction, and even an antimatter bomb to blow up the Vatican. If you thought you’d heard all the possible ways the LHC might cause cataclysmic disaster, think again: how about shifting the entire consciousness of humanity 21 years into the future? This is the plot of science-fiction author Robert Sawyer’s novel FlashForward, which is currently being transformed into a big-budget TV series. The Bulletin caught up with the author to find out more. The LHC is just about to start its first operation with lead ions. Suddenly the entire population of the world blacks out for about two minutes. During this time, every person on the planet experiences his life 21 years in the future. They wake up again in the present to see the mass destruction caused by this worldwide blackout, and are left to ponder over what they saw in the future. This is the plot of science-fiction author Robert Sawyer’s n...

  16. Secure and Efficient Electricity Supply. During the Transition to Low Carbon Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-07-01

    Electricity shortages can paralyse our modern economies. All governments fear rolling black-outs and their economic consequences, especially in economies increasingly based on digital technologies. Over the last two decades, the development of markets for power has produced cost reduction, technological innovation, increased cross border trade and assured a steady supply of electricity. Now, IEA countries face the challenge of maintaining security of electricity supply during the transition to low-carbon economies. Low-carbon policies are pushing electricity markets into novel territories at a time when most of the generation and network capacity will have to be replaced. Most notably, wind and solar generation, now an integral part of electricity markets, can present new operating and investment challenges for generation, networks and the regional integration of electricity markets. In addition, the resilience of power systems facing more frequent natural disasters is also of increasing concern. IEA Ministers mandated the Secretariat to work on the Electricity Security Action Plan (ESAP), expanding to electricity the energy security mission of the IEA. This paper outlines the key conclusions and policy recommendations to ''keep the lights on'' while reducing CO2 emissions and increasing the efficiency.

  17. Enabling Efficient, Responsive, and Resilient Buildings: Collaboration Between the United States and India

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Chandrayee; Ghatikar, Girish

    2013-09-25

    The United States and India have among the largest economies in the world, and they continue to work together to address current and future challenges in reliable electricity supply. The acceleration to efficient, grid-responsive, resilient buildings represents a key energy security objective for federal and state agencies in both countries. The weaknesses in the Indian grid system were manifest in 2012, in the country’s worst blackout, which jeopardized the lives of half of India’s 1.2 billion people. While both countries are investing significantly in power sector reform, India, by virtue of its colossal growth rate in commercial energy intensity and commercial floor space, is better placed than the United States to integrate and test state-of-art Smart Grid technologies in its future grid-responsive commercial buildings. This paper presents a roadmap of technical collaboration between the research organizations, and public-private stakeholders in both countries to accelerate the building-to-grid integration through pilot studies in India.

  18. Analysis of Thermal-Hydraulic Behavior of CMT in the SMART-ITL Facility

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Byong Guk; Bae, Hwang; Ryu, Sung-Uk; Ryu, Hyobong; Byun, Sun-Joon; Yi, Sung-Jae; Park, Hyun-Sik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    SMART, an integral small modular reactor, received a standard design approval in 2012 and now extends its safety features through replacing active safety injection pumps by passive safety injection systems: core makeup tanks (CMT) and safety injection tanks (SIT). SMART-ITL has been built in a full height scale and 1/49 area and power scale. One train of CMT and SIT has been installed and their thermal-hydraulic behaviors have been identified through a series of tests. In this paper, initial condensation characteristics as well as force balance around the CMT will be discussed for a representative test. PSIS are added into SMART for better treatment of accidents with prolonged station blackout. In the SMART-ITL, the CMT and SIT are installed to evaluate their performance and a series of tests have been conducted. In this paper, the thermal-hydraulic behavior of CMT is addressed based on the experimental data, especially focusing on the issues of fierce condensation after opening of the isolation valve and driving force balance around the CMT.

  19. Modeling and simulations on the propagation characteristics of electromagnetic waves in sub-atmospheric pressure plasma slab

    Science.gov (United States)

    Wang, Z. B.; Nie, Q. Y.; Li, B. W.; Kong, F. R.

    2017-01-01

    Sub-atmospheric pressure plasma slabs exhibit the feature of relatively high plasma number density and high collisional frequency between electrons and neutral gases, as well as similar thickness to the electromagnetic (EM) wavelength in communication bands. The propagation characteristics of EM waves in sub-atmospheric pressure plasma slabs are attracting much attention of the researchers due to their applications in the plasma antenna, the blackout effect during reentry, wave energy injection in the plasma, etc. In this paper, a numerical model with a one-dimensional assumption has been established and therefore, it is used for the investigations of the propagation characteristics of the EM waves in plasma slabs. In this model, the EM waves propagating in both sub-wavelength plasma slabs and plasmas with thicker slabs can be studied simultaneously, which is superior to the model with geometrical optics approximation. The influence of EM wave frequencies and collisional frequencies on the amplitude of the transmitted EM waves is discussed in typical plasma profiles. The results will be significant for deep understanding of the propagation behaviors of the EM waves in sub-atmospheric pressure nonuniform plasma slabs, as well as the applications of the interactions between EM waves and the sub-atmospheric pressure plasmas.

  20. Preliminary accident analysis of Flexblue® underwater reactor

    Directory of Open Access Journals (Sweden)

    Haratyk Geoffrey

    2015-01-01

    Full Text Available Flexblue® is a subsea-based, transportable, small modular reactor delivering 160 MWe. Immersion provides the reactor with an infinite heat sink – the ocean – around the metallic hull. The reference design includes a loop-type PWR with two horizontal steam generators. The safety systems are designed to operate passively; safety functions are fulfilled without operator action and external electrical input. Residual heat is removed through four natural circulation loops: two primary heat exchangers immersed in safety tanks cooled by seawater and two emergency condensers immersed in seawater. In case of a primary piping break, a two-train safety injection system is actuated. Each train includes a core makeup tank, an accumulator and a safety tank at low pressure. To assess the capability of these features to remove residual heat, the reactor and its safety systems have been modelled using thermal-hydraulics code ATHLET with conservative assumptions. The results of simulated transients for three typical PWR accidents are presented: a turbine trip with station blackout, a large break loss of coolant accident and a small break loss of coolant accident. The analyses show that the safety criteria are respected and that the reactor quickly reaches a safe shutdown state without operator action and external power.

  1. Optimal UPFC placement in Isfahan-Khozestan transmission network by using APSO algorithm for improving transient stability

    Directory of Open Access Journals (Sweden)

    Y. Rezaee

    2012-09-01

    Full Text Available Today power system works with a lower stability boundary due to increasing energy consumption. Increase of extensive blackouts in different points of the world in recent years clarifies that the power system stability should be improved. Using FACTS devices has a great role for improving power system stability. In this regard, locating UPFC in order to boost stability is getting important in power system studies. This paper develops a new optimal UPFC placement method by using adaptive PSO (APSO algorithm in Isfahan-Khozestan transmission network for improving static and transient stability. For UPFC placement, system voltage, loading and transmission line congestion, total power system losses, installation and operation cost constraints are considered. UPFC control system with supplementary control signal is modeled in details. All power system components, excitation system and load frequency control loops for all generators of Isfahan-Khozestan network in DIgSILENT software have been simulated. Simulation results show the remarkable effect of the proposed method for improving static and transient stability in under study system.

  2. Desire to dissociate: implications for problematic drinking in college students with childhood or adolescent sexual abuse exposure.

    Science.gov (United States)

    Klanecky, Alicia; McChargue, Dennis E; Bruggeman, Lindsay

    2012-01-01

    Alcohol use to replace inadequate dissociative capabilities, or chemical dissociation, has been linked to college students with childhood or adolescent sexual abuse (CASA). Insofar as CASA-exposed persons experience a restricted range of dissociative capabilities, what remains relatively unclear is whether some desire to achieve greater dissociative experiences. Nonclinical levels of dissociative tendencies have positively predicted alcohol-related blackouts in CASA-exposed students, and dissociation mediated the relations between CASA and intoxication frequency. Although alcohol (similar to dissociation) can reduce physiological and psychological responses to stress, alcohol consumption may be prompted by a desire to dissociate rather than inadequate dissociative tendencies alone. To investigate this interpretation of the chemical dissociation phenomenon, researchers examined the mediating potential of dissociative tendencies using the Dissociative Experiences Scale-II (DES-II) as well as the desire to dissociate concept (ie, a modified version of the DES-II) on the relations between CASA exposure and problematic alcohol use in college students (N = 298). Results indicated that dissociation scores did not replicate previous mediation findings whereas desire to dissociate scores fully mediated CASA exposure and problematic alcohol use. Implications of the results are discussed including possible reasons why prior mediation results were not replicated as well as links to experiential avoidance.

  3. AN AYURVEDIC INSIGHT TOWARDS EPILEPSY

    Directory of Open Access Journals (Sweden)

    Singh Karam

    2012-10-01

    Full Text Available In Ayurveda, Mental disorders and psychological temperaments have been broadly described [e.g. vata vyadhi (nervous disorders, unmada (insanity, murccha, moha (loss of consciousness, vismriti (amnesia, apasmara (epilepsy etc.]. In Ayurveda, Apasmara (or epilepsy has been described among the maharoga (a group of eight diseases well-known for causing serious morbidity. In the Ayurvedic texts, Apasmara (Epilepsy is defined as sudden abhorrent bodily activities (vibhatsa-cheshta accompanied by momentary blackouts or loss of consciousness (tama-pravesha owing to disturbance in mental faculties of dhi (intelligence, dhriti (retention and smriti (memory. Epilepsy is a major public health problem all over world. The estimated proportion of the general population with active epilepsy (i.e. continuing seizures or the need for treatment at a given time ranges from 4-10 per 1,000 people. Herbal remedies have been recommended in various medical treatises for the cure of different diseases. In this regard, there is great prospective for identifying excellent Ayurvedic components or its active principles, particularly in consideration of the fact that such substances may provide maximum advantage with cost effectiveness, least side effects, and improvement of patient compliance.

  4. Results of a Demonstration Assessment of Passive System Reliability Utilizing the Reliability Method for Passive Systems (RMPS)

    Energy Technology Data Exchange (ETDEWEB)

    Bucknor, Matthew; Grabaskas, David; Brunett, Acacia; Grelle, Austin

    2015-04-26

    Advanced small modular reactor designs include many advantageous design features such as passively driven safety systems that are arguably more reliable and cost effective relative to conventional active systems. Despite their attractiveness, a reliability assessment of passive systems can be difficult using conventional reliability methods due to the nature of passive systems. Simple deviations in boundary conditions can induce functional failures in a passive system, and intermediate or unexpected operating modes can also occur. As part of an ongoing project, Argonne National Laboratory is investigating various methodologies to address passive system reliability. The Reliability Method for Passive Systems (RMPS), a systematic approach for examining reliability, is one technique chosen for this analysis. This methodology is combined with the Risk-Informed Safety Margin Characterization (RISMC) approach to assess the reliability of a passive system and the impact of its associated uncertainties. For this demonstration problem, an integrated plant model of an advanced small modular pool-type sodium fast reactor with a passive reactor cavity cooling system is subjected to a station blackout using RELAP5-3D. This paper discusses important aspects of the reliability assessment, including deployment of the methodology, the uncertainty identification and quantification process, and identification of key risk metrics.

  5. BWR/5 Pressure-Suppression Pool Response during an SBO

    Directory of Open Access Journals (Sweden)

    Javier Ortiz-Villafuerte

    2013-01-01

    Full Text Available RELAP/SCDAPSIM Mod 3.4 has been used to simulate a station blackout occurring at a BWR/5 power station. Further, a simplified model of a wet well and dry well has been added to the NSSS model to study the response of the primary containment during the evolution of this accident. The initial event leading to severe accident was considered to be a LOOP with simultaneous scram. The results show that RCIC alone can keep the core fully covered, but even in this case about 30% of the original liquid water inventory in the PSP is vaporized. During the SBO, without RCIC, this inventory is reduced about 5% more within six hours. Further, a significant pressure rise occurs in containment at about the time when a sharp increase of heat generation occurs in RPV due to cladding oxidation. Failure temperature of fuel clad is also reached at this point. As the accident progresses, conditions for containment venting can be reached in about nine hours, although there still exists considerable margin before reaching containment design pressure. Detailed information of accident progress in reactor vessel and containment is presented and discussed.

  6. Controlled Tripping of Overheated Lines Mitigates Power Outages

    CERN Document Server

    Pfitzner, René; Chertkov, Michael

    2011-01-01

    We study cascades of blackouts in the model of the Polish (transmission) power grid (2700 nodes and 3504 transmission lines). A cascade is initiated by a sufficiently severe initial contingency tripping. The cascade advances via sequential tripping of many more overheated lines (with the thermal limits exceeded), islanding loads and generators and eventually arriving at a fixed point with the surviving part of the system being power- flow-balanced and the rest of the system being outaged. Utilizing the quasi-static model for cascade propagation, introduced in our earlier study (Statistical Classification of Cascading Failures in Power Grids, IEEE PES GM 2011), we analyze how the severity of the cascade depends on the order of tripping overheated lines. Our main observation is that the order of tripping has a tremendous effect on the size of the resulting outage: the probability distribution function of the outage size is broad; moreover in many of the cases studied, picking an overheated line at random result...

  7. Source Term Analysis for the Nuclear Power Station Goesgen-Daeniken; Quelltermanalysen fuer das Kernkraftwerk Goesgen-Daeniken

    Energy Technology Data Exchange (ETDEWEB)

    Hosemann, J.P.; Megaritis, G.; Guentay, S.; Hirschmann, H.; Luebbesmeyer, D.; Lieber, K.; Jaeckel, B.; Birchley, J.; Duijvestijn, G

    2001-08-01

    Analyses are performed for three accident scenarios postulated to occur in the Goesgen Nuclear Power Plant, a 900 MWe Pressurised Water Reactor of Siemens design. The scenarios investigated comprise a Station Blackout and two separate cases of small break loss-of-coolant accident which lead, respectively, to high, intermediate and low pressure conditions in the reactor system. In each case the accident assumptions are highly pessimistic, so that the sequences span a large range of plant states and a damage phenomena. Thus the plant is evaluated for a diversity of potential safety challenges. A suite of analysis tools are used to examine the reactor coolant system response, the core heat-up, melting, fission product release from the reactor system, the transport and chemical behaviour of those fission products in the containment building, and the release of radioactivity (source term) to the environment. Comparison with reference values used by the licensing authority shows that the use of modern analysis tools and current knowledge can provide substantial reduction in the estimated source term. Of particular interest are insights gained from the analyses which indicate opportunities for operators to reduce or forestall the release. (author)

  8. Multiple ground-based observations at Zhongshan Station during the April/May 1998 solar events

    Institute of Scientific and Technical Information of China (English)

    LIU; Ruiyuan(刘瑞源); HU; Hongqiao(胡红桥); HE; Longsong(贺龙松); LIU; Yonghua(刘勇华); LIU; Shunlin(刘顺林); LI; Shenggui(李胜桂); N.; Sato; B.; J.; Fraser

    2002-01-01

    Simultaneous observations at Zhongshan Station, Antarctica, during May 1-7, 1998 are presented to show the responses of the polar ionosphere to the April/May 1998 solar events. One of the main geo-effects of the solar events resulted in the major magnetic storm on May 4. At the storm onset on May 2 the ionosphere F2 layer abruptly increased in altitude, the geomagnetic H-component started negative deviation and the spectral amplitude of the ULF wave intensified. Both large isolated riometer absorption and large negative deviation of the geomagnetic H-component occurred at about 0639UT. There was a time lag of about one hour and ten minutes between the storm onset and the IMF southward turning, as measured by the WIND satellite. The polar ionosphere was highly disturbed, as shown by frequent large deviations of the geomagnetic H-component, large riometer absorption events and strong ULF waves in all the courses of the storm. The absorption increased greatly causing the digisonde to be blackout most of the time. However, the data still showed a substantial decrease in the F2 electron density and oscillation of the F2 layer peak height with an amplitude exceeding 200 km.

  9. High Flux Isotope Reactor system RELAP5 input model

    Energy Technology Data Exchange (ETDEWEB)

    Morris, D.G.; Wendel, M.W.

    1993-01-01

    A thermal-hydraulic computational model of the High Flux Isotope Reactor (HFIR) has been developed using the RELAP5 program. The purpose of the model is to provide a state-of-the art thermal-hydraulic simulation tool for analyzing selected hypothetical accident scenarios for a revised HFIR Safety Analysis Report (SAR). The model includes (1) a detailed representation of the reactor core and other vessel components, (2) three heat exchanger/pump cells, (3) pressurizing pumps and letdown valves, and (4) secondary coolant system (with less detail than the primary system). Data from HFIR operation, component tests, tests in facility mockups and the HFIR, HFIR specific experiments, and other pertinent experiments performed independent of HFIR were used to construct the model and validate it to the extent permitted by the data. The detailed version of the model has been used to simulate loss-of-coolant accidents (LOCAs), while the abbreviated version has been developed for the operational transients that allow use of a less detailed nodalization. Analysis of station blackout with core long-term decay heat removal via natural convection has been performed using the core and vessel portions of the detailed model.

  10. HARDRONIC 2011

    CERN Multimedia

    2011-01-01

    This year’s world-famous Hardronic Festival will take place on Friday 22nd July and Saturday 23rd July on the terrace behind restaurant 3 at Prevessin. There will be lots of live music from all your favourite CERN bands plus food, drink on both days with stuff for kids to do on Saturday. So, if you have not got your ticket for Montreux or Paleo, put the dates in your diaries and spend the weekend listening to some great live music (and, unlike Paleo and Montreux, it’s FREE!!!!)   Things get started at 17h30 on both days and the program is as follows:- Friday 22nd July: 17h30 – Hadron/JamBand 19h00 - Tony Arnold 20h00 - Blend 21h00 - The Canettes 22h00 - Miss Proper 23h00 - Shocking Pink 24h00 - D'ANGLERZ Saturday 23rd July: 17h30 – Hadron/JamBand 18h00 - Malavida (provisional) 19h00 - Awesome 20h00 - The Tape Trade 21h00 - Data?Fail! 22h00 - Sour Hurricane 23h00 - Physt 24h00 - Total Blackout More information on the CERN MusiClub here. &...

  11. Assessment of terrorist threats to the Canadian energy sector

    Energy Technology Data Exchange (ETDEWEB)

    Shull, A. [Carleton Univ., Ottawa, ON (Canada). Norman Paterson School of International Affairs]|[Ottawa Univ., ON (Canada). Faculty of Law

    2006-03-15

    A critical terrorist threat assessment of Canadian energy systems was presented, as well as an analysis of integrated continental systems. Recent responses to heightened threat levels on the part of the Canadian government have ranged from information sharing to emergency preparedness and disaster mitigation strategies. This paper examined threats that the energy sector has traditionally encountered and argued that response capabilities do not match current threats posed by terrorism. The potential of a terrorist attack on the Canadian energy infrastructure is significant and has been referred to as a possible target by terrorist organizations. Actions taken by the Canadian government in response to heightened threat levels were examined. A review of energy industry security measures included outlines of: the natural gas industry, the electric sector, and nuclear reactors and waste. It was noted that not all elements of the critical energy infrastructure share the same level of risk. Recommendations included increased information sharing between government agencies and the private sector; resiliency standards in densely populated areas; and insulating the energy grid against a cascading blackout through the use of DC rather than AC lines. 59 refs.

  12. Preliminary Analysis on Heat Removal Capacity of Passive Air-Water Combined Cooling Heat Exchanger Using MARS

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung-Sin; Jeon, Seong-Su; Hong, Soon-Joon [FNC Tech, Yongin (Korea, Republic of); Bae, Sung-Won; Kwon, Tae-Soon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Current design requirement for working time of PAFS heat exchanger is about 8 hours. Thus, it is not satisfied with the required cooling capability for the long term SBO(Station Black-Out) situation that is required to over 72 hours cooling. Therefore PAFS is needed to change of design for 72 hours cooling. In order to acquirement of long terms cooling using PAFS, heat exchanger tube has to be submerged in water tank for long time. However, water in the tank is evaporated by transferred heat from heat exchanger tubes, so water level is gradually lowered as time goes on. The heat removal capacity of air cooling heat exchanger is core parameter that is used for decision of applicability on passive air-water combined cooling system using PAFS in long term cooling. In this study, the development of MARS input model and plant accident analysis are performed for the prediction of the heat removal capacity of air cooling heat exchanger. From analysis result, it is known that inflow air velocity is the decisive factor of the heat removal capacity and predicted air velocity is lower than required air velocity. But present heat transfer model and predicted air velocity have uncertainty. So, if changed design of PAFS that has over 4.6 kW heat removal capacity in each tube, this type heat exchanger can be applied to long term cooling of the nuclear power plant.

  13. Pre-test analysis of ATLAS SBO with RCP seal leakage scenario using MARS code

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Quang Huy; Lee, Sang Young; Oh, Seung Jong [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2015-10-15

    This study presents a pre-test calculation for the Advanced Thermal-hydraulic Test Loop for Accident Simulation (ATLAS) SBO experiment with RCP seal leakage scenario. Initially, turbine-driven auxfeed water pumps are used. Then, outside cooling water injection method is used for long term cooling. The analysis results would be useful for conducting the experiment to verify the APR 1400 extended SBO optimum mitigation strategy using outside cooling water injection in future. The pre-test calculation for ATLAS extended SBO with RCP seal leakage and outside cooling water injection scenario is performed. After Fukushima nuclear accident, the capability of coping with the extended station blackout (SBO) becomes important. Many NPPs are applying FLEX approach as main coping strategies for extended SBO scenarios. In FLEX strategies, outside cooling water injection to reactor cooling system (RCS) and steam generators (SGs) is considered as an effective method to remove residual heat and maintain the inventory of the systems during the accident. It is worthwhile to examine the soundness of outside cooling water injection method for extended SBO mitigation by both calculation and experimental demonstration. From the calculation results, outside cooling water injection into RCS and SGs is verified as an effective method during extended SBO when RCS and SGs depressurization is sufficiently performed.

  14. Wide area measurement system for smart grid applications involving hybrid energy sources

    Energy Technology Data Exchange (ETDEWEB)

    Amin, Mahmoud M.; Moussa, Heba B.; Mohammed, Osama A. [Florida International University, Energy Systems Research Laboratory, Department of Electrical and Computer Engineering, Miami, FL (United States)

    2012-03-15

    This paper presents a model and experimental verification for a complete scenario of a proposed wide area measurement system (WAMS) based on synchronized phasor measurement units (PMUs). The proposed system is feasible for hybrid smart ac/dc power networks; such as grid-connected PV-power plants. The purpose is to increase the overall system reliability for all power stages via significant dependence on WAMS as distributed intelligence agents with improved monitoring, protection, and control capabilities of the power networks. The developed system is simulated in the Matlab/Simulink environment. The system was tested under two different cases; normal operation and fault state. Furthermore, the proposed WAMS was experimentally validated with results obtained from a reduced scale setup which built and tested in the laboratory based on the Hardware-in-the-loop concept. It was verified that the power system status can be easily monitored and controlled in real time by using the measured bus data in real time. This improves the overall system reliability and avoids cascaded blackout during fault occurrence. The simulation and experimental results confirm the validity of the proposed WAMS technology for smart grid applications. (orig.)

  15. Operations managers conference: summary of proceedings. [Carmel, California, Feb. 13-15, 1979

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-02-01

    The fifth AESOP Operations Managers Conference was held in Carmel, California on February 13-15, 1979. The keynote address dealt with the changing role of the computer operations manager. Representatives presented contrasting approaches to managing the procurement and installation of new computer systems. The advantages and disadvantages of maintaining strong internal management support and good communication with the vendor and of increasing the involvement of broad-based planning committees and operations personnel in the computer procurement process were discussed. Two promising management programs, the PEER and 10/40 systems proved effective in improving employee morale by reducing job fragmentation, increasing internal mobility and modifying the work week. The topic of unionization of operations personnel was also discussed. The uneasy relationship between computers and the energy shortage was also considered. Techniques for avoiding computer problems caused by blackouts and brownouts were presented. The difficulty of conserving power at a computer facility was also discussed. Presentations concerning the President's committee on ADP reorganizaion and methods for predicting trends in computer innovation were made. Abstracts and two-page summaries of the papers given are included in this report.

  16. Smart Ultrasound Remote Guidance Experiment (SURGE) Preliminary Findings

    Science.gov (United States)

    Hurst, Victor; Dulchavsky, Scott; Garcia, Kathleen; Sargsyan, Ashot; Ebert, Doug

    2009-01-01

    To date, diagnostic quality ultrasound images were obtained aboard the International Space Station (ISS) using the ultrasound of the Human Research Facility (HRF) rack in the Laboratory module. Through the Advanced Diagnostic Ultrasound in Microgravity (ADUM) and the Braslet-M Occlusion Cuffs (BRASLET SDTO) studies, non-expert ultrasound operators aboard the ISS have performed cardiac, thoracic, abdominal, vascular, ocular, and musculoskeletal ultrasound assessments using remote guidance from ground-based ultrasound experts. With exploration class missions to the lunar and Martian surfaces on the horizon, crew medical officers will necessarily need to operate with greater autonomy given communication delays (round trip times of up to 5 seconds for the Moon and 90 minutes for Mars) and longer periods of communication blackouts (due to orbital constraints of communication assets). The SURGE project explored the feasibility and training requirements of having non-expert ultrasound operators perform autonomous ultrasound assessments in a simulated exploration mission outpost. The project aimed to identify experience, training, and human factors requirements for crew medical officers to perform autonomous ultrasonography. All of these aims pertained to the following risks from the NASA Bioastronautics Road Map: 1) Risk 18: Major Illness and Trauna; 2) Risk 20) Ambulatory Care; 3) Risk 22: Medical Informatics, Technologies, and Support Systems; and 4) Risk 23: Medical Skill Training and Maintenance.

  17. Chips 2020

    CERN Document Server

    2016-01-01

    The release of this second volume of CHIPS 2020 coincides with the 50th anniversary of Moore’s Law, a critical year marked by the end of the nanometer roadmap and by a significantly reduced annual rise in chip performance. At the same time, we are witnessing a data explosion in the Internet, which is consuming 40% more electrical power every year, leading to fears of a major blackout of the Internet by 2020. The messages of the first CHIPS 2020, published in 2012, concerned the realization of quantum steps for improving the energy efficiency of all chip functions. With this second volume, we review these messages and amplify upon the most promising directions: ultra-low-voltage electronics, nanoscale monolithic 3D integration, relevant-data, brain- and human-vision-inspired processing, and energy harvesting for chip autonomy. The team of authors, enlarged by more world leaders in low-power, monolithic 3D, video, and Silicon brains, presents new vistas in nanoelectronics, promising  Moore-like exponential g...

  18. Interviewing insights regarding the fatalities inflicted by the 2011 Great East Japan Earthquake

    Science.gov (United States)

    Ando, M.; Ishida, M.; Hayashi, Y.; Mizuki, C.; Nishikawa, Y.; Tu, Y.

    2013-09-01

    One hundred fifty survivors of the 11 March 2011 Great East Japan Earthquake (Tohoku-oki earthquake) (Mw = 9.0) were interviewed to study the causes of deaths from the associated tsunami in coastal areas of Tohoku. The first official tsunami warning underestimated the height of the tsunami and 40% of the interviewees did not obtain this warning due to immediate blackouts and a lack of communication after the earthquake. Many chose to remain in dangerous locations based on the underestimated warning and their experiences with previous smaller tsunamis and/or due to misunderstanding the mitigating effects of nearby breakwaters in blocking incoming tsunamis. Some delayed their evacuation to perform family safety checks, and in many situations, the people affected misunderstood the risks involved in tsunamis. In this area, three large tsunamis have struck in the 115 yr preceding the 2011 tsunami. These tsunamis remained in the collective memory of communities, and numerous measures against future tsunami damage, such as breakwaters and tsunami evacuation drills, had been implemented. Despite these preparedness efforts, approximately 18 500 deaths and cases of missing persons occurred. The death rate with the age of 65 and above was particularly high, four times higher than that with other age groups. These interviews indicate that deaths resulted from a variety of reasons, but if residents had taken immediate action after the major ground motion stopped, most residents might have been saved. Education about the science behind earthquakes and tsunamis could help save more lives in the future.

  19. Ionospheric Effects of X-Ray Solar Bursts in the Brazilian Sector

    Science.gov (United States)

    Becker-Guedes, F.; Takahashi, H.; Costa, J. E.; Otsuka, Y.

    2011-12-01

    When the solar X-ray flux in the interplanetary medium reaches values above a certain threshold, some undesired effects affecting radio communications are expected. Basically, the magnitudes of these effects depend on the X-ray peak brightness and duration, which drive the intensity of the ionosphere response when the associated electromagnetic wave hit the sunlit side of the Earth atmosphere. An important aspect defining the severity of damages to HF radio communications and LF navigation signals in a certain area is the local time when each event takes place. In order to create more accurate warnings referred to possible radio signal loss or degradation in the Brazilian sector, we analyze TEC maps obtained by a GPS network, formed by dual-frequency receivers spread all over the country, to observe ionospheric local changes during several X-ray events in the 0.1-0.8 nm range measured by GOES satellite. Considering the duration, peak brightness, and local time of the events, the final purpose of this study is to understand and predict the degree of changes suffered by the ionosphere during these X-ray bursts. We intend using these results to create a radio blackout warning product to be offered by the Brazilian space weather program named EMBRACE (Estudo e Monitoramento BRAsileiro do Clima Espacial): Brazilian Monitoring and Study of Space Weather.

  20. Optimizing the robustness of electrical power systems against cascading failures.

    Science.gov (United States)

    Zhang, Yingrui; Yağan, Osman

    2016-06-21

    Electrical power systems are one of the most important infrastructures that support our society. However, their vulnerabilities have raised great concern recently due to several large-scale blackouts around the world. In this paper, we investigate the robustness of power systems against cascading failures initiated by a random attack. This is done under a simple yet useful model based on global and equal redistribution of load upon failures. We provide a comprehensive understanding of system robustness under this model by (i) deriving an expression for the final system size as a function of the size of initial attacks; (ii) deriving the critical attack size after which system breaks down completely; (iii) showing that complete system breakdown takes place through a first-order (i.e., discontinuous) transition in terms of the attack size; and (iv) establishing the optimal load-capacity distribution that maximizes robustness. In particular, we show that robustness is maximized when the difference between the capacity and initial load is the same for all lines; i.e., when all lines have the same redundant space regardless of their initial load. This is in contrast with the intuitive and commonly used setting where capacity of a line is a fixed factor of its initial load.

  1. WHEN MODEL MEETS REALITY – A REVIEW OF SPAR LEVEL 2 MODEL AGAINST FUKUSHIMA ACCIDENT

    Energy Technology Data Exchange (ETDEWEB)

    Zhegang Ma

    2013-09-01

    The Standardized Plant Analysis Risk (SPAR) models are a set of probabilistic risk assessment (PRA) models used by the Nuclear Regulatory Commission (NRC) to evaluate the risk of operations at U.S. nuclear power plants and provide inputs to risk informed regulatory process. A small number of SPAR Level 2 models have been developed mostly for feasibility study purpose. They extend the Level 1 models to include containment systems, group plant damage states, and model containment phenomenology and accident progression in containment event trees. A severe earthquake and tsunami hit the eastern coast of Japan in March 2011 and caused significant damages on the reactors in Fukushima Daiichi site. Station blackout (SBO), core damage, containment damage, hydrogen explosion, and intensive radioactivity release, which have been previous analyzed and assumed as postulated accident progression in PRA models, now occurred with various degrees in the multi-units Fukushima Daiichi site. This paper reviews and compares a typical BWR SPAR Level 2 model with the “real” accident progressions and sequences occurred in Fukushima Daiichi Units 1, 2, and 3. It shows that the SPAR Level 2 model is a robust PRA model that could very reasonably describe the accident progression for a real and complicated nuclear accident in the world. On the other hand, the comparison shows that the SPAR model could be enhanced by incorporating some accident characteristics for better representation of severe accident progression.

  2. 基于DS1302的断电记录系统的设计%The Design of power system recording based on DS1302

    Institute of Scientific and Technical Information of China (English)

    骆定辉

    2013-01-01

    This paper introduces the use of timing chip DS1302, memory chip AT24C256, AT89C52 microcontroller, display chip HD7279 and LED digital tube display system module, the system takes the MCU as a core, Record the power outage time, assist the environmental protection departments illegal blackout for key pollution sources on-line monitoring system to monitor.%  本文介绍了利用计时芯片DS1302、存储芯片AT24C256、单片机AT89C52、显示芯片HD7279以及LED数码管显示模块组成的系统,本系统以单片机为核心,记录下电源的断电时间,协助环境保护部门对重点污染源在线监控系统的非法停电进行监督。

  3. Oil and Gas Emergency Policy: Chile 2012 update

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-09-06

    Chile has experienced several serious energy supply incidents over the last decade, including major droughts, a sustained gas supply cut from Argentina (since 2004), and a major earthquake in early 2010 which affected electricity networks and refineries, and caused several black-outs. Due to Chile's unique and sinuous geography - it runs 4 300 kilometres from North to South and only 175 kms from East to West- the country's energy markets are regionally disjointed, particularly as the regional gas and electricity grids are not connected. In the arid North, energy demand is dominated by the mining industry, and operates based on a separate thermal-based Sistema Interconectado Norte Grande (SING) electricity grid. The more densely-populated central region (including Santiago) operates on the more hydro-dependent Sistema Interconectado Central (SIC) electricity grid. The southernmost, hydro-rich regions of the country are not connected to the rest of Chile in terms of electricity and gas. The following report is based on an IEA Emergency Response Assessment carried out in 2010 and 2011 which looked specifically at Chile's capacity to respond to short-term emergencies in oil, gas and electricity.

  4. Identifying classes of conjoint alcohol and marijuana use in entering freshmen.

    Science.gov (United States)

    Haas, Amie L; Wickham, Robert; Macia, Kathryn; Shields, Micah; Macher, Rayna; Schulte, Tilman

    2015-09-01

    The current study identified classes of conjoint marijuana and alcohol use in entering college freshmen using latent profile analysis (N = 772; 53% male, 60% White; Mage = 18). Results yielded 4 distinct groups: Class 1 (moderate drinking with recent marijuana use: 22% of sample), Class 2 (moderate drinking with no recent marijuana use: 25%), Class 3 (light drinking with no recent marijuana use: 40%) and Class 4 (heavy drinking with recent marijuana use: 14%). Separate pairwise contrasts examined cross-class differences in demographics and drinking behaviors, comparing differences in drinking when current marijuana use was controlled (Class 1 vs. 4) and differences in marijuana use when drinking was held relatively constant (Class 1 vs. 2). Among moderate drinkers, recent marijuana users were more likely to drink more than intended, drink to get drunk, and had more problems (including higher rates of blackouts, physical injury, and DUI) relative to peers who refrained from marijuana. No cross-class differences were found for alcohol expectancies or behavioral motives. Findings from these analyses show the presence of distinct groups of conjoint users with different drinking behaviors and consequence profiles, and suggest that conjoint alcohol-marijuana use may be more problematic overall than single substance involvement and highlight the need for developing campus prevention and intervention programs that address the increased risk from polysubstance involvement.

  5. A large volume uniform plasma generator for the experiments of electromagnetic wave propagation in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Yang Min; Li Xiaoping; Xie Kai; Liu Donglin [School of Electronical and Mechanical Engineering, Xidian University, Xi' an Shaanxi 710071 (China); Liu Yanming [School of Telecommunications Engineering, Xidian University, Xi' an Shaanxi 710071 (China)

    2013-01-15

    A large volume uniform plasma generator is proposed for the experiments of electromagnetic (EM) wave propagation in plasma, to reproduce a 'black out' phenomenon with long duration in an environment of the ordinary laboratory. The plasma generator achieves a controllable approximate uniform plasma in volume of 260 mm Multiplication-Sign 260 mm Multiplication-Sign 180 mm without the magnetic confinement. The plasma is produced by the glow discharge, and the special discharge structure is built to bring a steady approximate uniform plasma environment in the electromagnetic wave propagation path without any other barriers. In addition, the electron density and luminosity distributions of plasma under different discharge conditions were diagnosed and experimentally investigated. Both the electron density and the plasma uniformity are directly proportional to the input power and in roughly reverse proportion to the gas pressure in the chamber. Furthermore, the experiments of electromagnetic wave propagation in plasma are conducted in this plasma generator. Blackout phenomena at GPS signal are observed under this system and the measured attenuation curve is of reasonable agreement with the theoretical one, which suggests the effectiveness of the proposed method.

  6. Finite element based stress analysis of BWR internals exposed to accident loads

    Energy Technology Data Exchange (ETDEWEB)

    Altstadt, E.; Weiss, F.P.; Werner, M.; Willschuetz, H.G.

    1998-10-01

    During a hypothetical accident the reactor pressure vessel internals of boiling water reactors can be exposed to considerable loads resulting from temperature gradients and pressure waves. Three dimensional FE models were developed for the core shroud, the upper and the lower core supporting structure, the steam separator pipes and the feed water distributor. The models of core shroud, upper core structure and lower core structure were coupled by means of the substructure technique. All FE models can be used for thermal and for structural mechanical analyses. As an example the FE analysis for the case of a station black-out scenario (loss of power supply for the main circulating pumps) with subsequent emergency core cooling is demonstrated. The transient temperature distributions within the core shroud and within the steam dryer pipes as well were calculated based on the fluid temperatures and the heat transfer coefficients provided by thermo-hydraulic codes. At the maximum temperature gradients in the core shroud, the mechanical stress distribution was computed in a static analysis with the actual temperature field being the load. (orig.)

  7. Wind Generation Participation in Power System Frequency Response: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Gevorgian, Vahan; Zhang, Yingchen

    2017-01-01

    The electrical frequency of an interconnected power system must be maintained close its nominal level at all times. Excessive under- and overfrequency excursions can lead to load shedding, instability, machine damage, and even blackouts. There is a rising concern in the electric power industry in recent years about the declining amount of inertia and primary frequency response (PFR) in many interconnections. This decline may continue due to increasing penetrations of inverter-coupled generation and the planned retirements of conventional thermal plants. Inverter-coupled variable wind generation is capable of contributing to PFR and inertia with a response that is different from that of conventional generation. It is not yet entirely understood how such a response will affect the system at different wind power penetration levels. The modeling work presented in this paper evaluates the impact of wind generation's provision of these active power control strategies on a large, synchronous interconnection. All simulations were conducted on the U.S. Western Interconnection with different levels of instantaneous wind power penetrations (up to 80%). The ability of wind power plants to provide PFR - and a combination of synthetic inertial response and PFR - significantly improved the frequency response performance of the system.

  8. Development of a hydrogen diffusion gothic model of MARK III-containment

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Zhen-Yu [National Tsing Hua Univ., Dept. of Engineering and System Science, Hsinchu, Taiwan (China); Huang, Yu-Kai; Pei, Bau-Shei [National Tsing Hua Univ., Inst. of Nuclear Engineering Science, Hsinchu, Taiwan (China); Hsu, Wen-Sheng [National Tsing Hua Univ., Nuclear Science and Technology Development Center, Hsinchu, Taiwan (China); Chen, Yen-Shu [Institute of Nuclear Energy Research, Nuclear Engineering Div., Taiyuan County, Taiwan (China)

    2015-07-15

    The accident that occurred at the Fukushima Daiichi Nuclear Power Plant is a reminder of the danger of hydrogen explosion within a reactor building. Sufficiently high hydrogen concentration may cause an explosion that could damage the structure, resulting in the release of radioisotopes into the environment. In the first part of this study, a gas diffusion experiment was performed, in which helium was used as the working fluid. An analytical model was also developed using the GOTHIC code and the model predictions of the helium distribution were found to be in good agreement with the experimentally measured data. In the second part of the study, a model of the Mark III containment of the Kuosheng Plant in Taiwan was developed, and was applied to a long-term station blackout (SBO) accident similar to that of the Fukushima plant. The hydrogen generation was calculated using the Modular Accident Analysis Program and was used as the boundary condition for the GOTHIC containment model. The simulation results revealed that the hydrogen concentration at the first floor of the wetwell in the containment reached 4 % 9.7 h after the accident. This indicated the possibility of dangerous conditions inside the containment. Although active hydrogen ignitors are already installed in the Kuosheng plant, the findings of this study indicate that it may be necessary to add passive recombiners to prolong an SBO event.

  9. Visual and proprioceptive contributions to postural control of upright stance in unilateral vestibulopathy.

    Science.gov (United States)

    Eysel-Gosepath, Katrin; McCrum, Christopher; Epro, Gaspar; Brüggemann, Gert-Peter; Karamanidis, Kiros

    2016-06-01

    Preserving upright stance requires central integration of the sensory systems and appropriate motor output from the neuromuscular system to keep the centre of pressure (COP) within the base of support. Unilateral peripheral vestibular disorder (UPVD) causes diminished stance stability. The aim of this study was to determine the limits of stability and to examine the contribution of multiple sensory systems to upright standing in UPVD patients and healthy subjects. We hypothesized that closure of the eyes and Achilles tendon vibration during upright stance will augment the postural sway in UPVD patients more than in healthy subjects. Seventeen UPVD patients and 17 healthy subjects performed six tasks on a force plate: forwards and backwards leaning, to determine limits of stability, and upright standing with and without Achilles tendon vibration, each with eyes open and closed (with blackout glasses). The COP displacement of the patients was significantly greater in the vibration tasks than the controls and came closer to the posterior base of support boundary than the controls in all tasks. Achilles tendon vibration led to a distinctly more backward sway in both subject groups. Five of the patients could not complete the eyes closed with vibration task. Due to the greater reduction in stance stability when the proprioceptive, compared with the visual, sensory system was disturbed, we suggest that proprioception may be more important for maintaining upright stance than vision. UPVD patients, in particular, showed more difficulty in controlling postural stability in the posterior direction with visual and proprioceptive sensory disturbance.

  10. Solar Flare Measurements with STIX and MiSolFA

    CERN Document Server

    Casadei, Diego

    2014-01-01

    Solar flares are the most powerful events in the solar system and the brightest sources of X-rays, often associated with emission of particles reaching the Earth and causing geomagnetic storms, giving problems to communication, airplanes and even black-outs. X-rays emitted by accelerated electrons are the most direct probe of solar flare phenomena. The Micro Solar-Flare Apparatus (MiSolFA) is a proposed compact X-ray detector which will address the two biggest issues in solar flare modeling. Dynamic range limitations prevent simultaneous spectroscopy with a single instrument of all X-ray emitting regions of a flare. In addition, most X-ray observations so far are inconsistent with the high anisotropy predicted by the models usually adopted for solar flares. Operated at the same time as the STIX instrument of the ESA Solar Orbiter mission, at the next solar maximum (2020), they will have the unique opportunity to look at the same flare from two different directions: Solar Orbiter gets very close to the Sun wit...

  11. Effects on the Floor Response Spectra by the Nonlinear Behavior of a Seismic Base Isolation System

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyungkui; Kim, Jung Han; Choi, Inkil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    An evaluation of safety being carried out for various risk factors of prevents for nuclear power plant accident. In general, an evaluation of the structural integrity was performed about seismic risk. In recent years, an assessment of integrity of internal equipment being carried out for earthquake loads owing to the possibility of severe accidents caused by the destruction of internal equipment or a blackout. Floor response spectra of the structure should be sought for evaluating of the integrity of internal equipment. The floor response spectra depends on the characteristics of seismic base isolation system such as the natural frequency, damping ratio, and height of the floor of the structure. An evaluation of the structural integrity using the equivalent stiffness of the seismic base isolation system was satisfactory. In this study, the effect of the non-linearity of isolated system in the floor response spectrum of the structure is analyzed. In this study, the floor response spectrum of the seismic base isolation system by the non-linear effect of the rubber isolator was analyzed. As a result, the influence of the non-linear isolated system was increased in hi-frequency domain. In addition, each floor exhibited a more different of responses compared with the equivalent linear model of the isolated structure. The non-linearity of the isolation system of the structure was considered, because of a more reliable assessment of integrity of equipment at each floor of seismic base the isolation system.

  12. Substance use, sexual behaviour and prevention strategies of Vancouver gay and bisexual men who recently attended group sex events.

    Science.gov (United States)

    Rich, Ashleigh J; Lachowsky, Nathan J; Cui, Zishan; Sereda, Paul; Lal, Allan; Birch, Robert; Montaner, Julio; Moore, David; Hogg, Robert S; Roth, Eric A

    2016-01-01

    Group sex events are an epidemiologically important part of some gay and bisexual men's sexual culture in Canada. Associated with condomless anal intercourse and polysubstance use, such events have been cited as disproportionally contributing to HIV infection rates. We analysed questionnaire data from the Momentum Health Study in Vancouver, Canada, to understand substance use, sexual behaviour, psychosocial variables (Sexual Sensation Seeking, Sexual Escape Motivation, Treatment Optimism) and HIV prevention strategies (sero-sorting, strategic positioning, avoiding anal sex, disclosure, treatment as prevention) of men attending such events, which were defined as group (n ≥ 4 partners) sex parties, blackout events and darkrooms. Analysis by multivariable logistic regression compared men attending group sex events within the past six months (n = 180) with non-attendees (n = 539). Results showed that attendees reported: (1) significantly higher use of sex drugs and alcohol consumption, (2) higher scores on the Sexual Sensation Scale, more anal sex partners, greater odds of any condomless anal sex with sero-discordant partners and greater odds of reporting fisting and sex toy use and (3) different prevention practices that varied by HIV-serostatus. Findings are interpreted in light of the importance of pleasure, sociality and HIV/STI prevention strategies associated with group sex events. Findings contribute to the development of appropriate education and intervention for attendees.

  13. THE TECHNOLOGY ASSESSMENT OF DEMAND SIDE BIDDING IN THE SOUTH AFRICAN CONTEXT*

    Directory of Open Access Journals (Sweden)

    H.K. Grover

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT:South Africa is currently in the grip of a severe power supply capacity constraint. January 2007 saw blackouts throughout the country, and worse was expected in the months to come. As a measure of immediate remedy Eskom has turned to demand side bidding (DSB, a methodology whereby the demand side has an opportunity to sell back flexible load to the supply side. This paper assesses DSB with the aim of evaluating and gauging the current and potential future standing of DSB as a technology product within the South African context.

    AFRIKAANSE OPSOMMING: Suid-Afrika ervaar tans ’n ernstige vraagstuk in elektrisiteitsvoorsiening. Vanaf Januarie 2007 kom gereelde kragonderbrekings voor, en volgens alle aanduidings lê die ergste nog voor. As ’n korttermynmaatreël beoog ESKOM ’n strategie van aanvraagbestuur en spesifiek aanvraag-bie, ’n metodologie waarvolgens verbruikers die geleentheid kry om elektrisiteit aan die verskaffer terug te verkoop. Hierdie artikel assesseer die metodologie ten einde die huidige en toekomstige gebruikersmoontlikhede daarvan as ’n tegnologieproduk binne Suid-Afrikaanse konteks te bepaal.

  14. The CERTS microgrid and the future of the macrogrid

    Energy Technology Data Exchange (ETDEWEB)

    Marnay, Chris; Bailey, Owen C.

    2004-06-01

    The blackouts of summer 2003 underscored the dependence of western economies on reliable supply of electricity with tight tolerances of quality. While demand for electricity continues to grow, expansion of the traditional electricity supply system is constrained and is unlikely to keep pace with the growing thirst western economies have for electricity. Furthermore, no compelling case has been made that perpetual improvement in the overall power quality and reliability (PQR) delivered is possible or desirable. An alternative path to providing for sensitive loads is to provide for generation close to them. This would alleviate the pressure for endless improvement in grid PQR and might allow the establishment of a sounder economically based level of universal grid service. Providing for loads by means of local power generation is becoming increasingly competitive with central station generation for a number of reasons, four key ones being non-technical constraints on expansion of the grid, improvements in small scale technologies, opportunities for CHP application, and the ubiquitous nature of sensitive loads in advanced economies. Along with these new technologies, concepts for operating them partially under local control in microgrids are emerging, the CERTS Microgrid being one example. It has been demonstrated in simulation, and a laboratory test of a three microturbine system is planned for early 2005, to be followed by a field demonstration. A systemic energy analysis of a southern California naval base building demonstrates a current economic on-site power opportunity.

  15. Distributed Power Control Network and Green Building Test-Bed for Demand Response in Smart Grid

    Science.gov (United States)

    Sakaguchi, Kei; Nguyen, Van Ky; Tao, Yu; Tran, Gia Khanh; Araki, Kiyomichi

    It is known that demand and supply power balancing is an essential method to operate power delivery system and prevent blackouts caused by power shortage. In this paper, we focus on the implementation of demand response strategy to save power during peak hours by using Smart Grid. It is obviously impractical with centralized power control network to realize the real-time control performance, where a single central controller measures the huge metering data and sends control command back to all customers. For that purpose, we propose a new architecture of hierarchical distributed power control network which is scalable regardless of the network size. The sub-controllers are introduced to partition the large system into smaller distributed clusters where low-latency local feedback power control loops are conducted to guarantee control stability. Furthermore, sub-controllers are stacked up in an hierarchical manner such that data are fed back layer-by-layer in the inbound while in the outbound control responses are decentralized in each local sub-controller for realizing the global objectives. Numerical simulations in a realistic scenario of up to 5000 consumers show the effectiveness of the proposed scheme to achieve a desired 10% peak power saving by using off-the-shelf wireless devices with IEEE802.15.4g standard. In addition, a small scale power control system for green building test-bed is implemented to demonstrate the potential use of the proposed scheme for power saving in real life.

  16. The atmospheric implications of radiation belt remediation

    Directory of Open Access Journals (Sweden)

    C. J. Rodger

    2006-08-01

    Full Text Available High altitude nuclear explosions (HANEs and geomagnetic storms can produce large scale injections of relativistic particles into the inner radiation belts. It is recognised that these large increases in >1 MeV trapped electron fluxes can shorten the operational lifetime of low Earth orbiting satellites, threatening a large, valuable population. Therefore, studies are being undertaken to bring about practical human control of the radiation belts, termed "Radiation Belt Remediation" (RBR. Here we consider the upper atmospheric consequences of an RBR system operating over either 1 or 10 days. The RBR-forced neutral chemistry changes, leading to NOx enhancements and Ox depletions, are significant during the timescale of the precipitation but are generally not long-lasting. The magnitudes, time-scales, and altitudes of these changes are no more significant than those observed during large solar proton events. In contrast, RBR-operation will lead to unusually intense HF blackouts for about the first half of the operation time, producing large scale disruptions to radio communication and navigation systems. While the neutral atmosphere changes are not particularly important, HF disruptions could be an important area for policy makers to consider, particularly for the remediation of natural injections.

  17. Processing- and product-related causes for food waste and implications for the food supply chain.

    Science.gov (United States)

    Raak, Norbert; Symmank, Claudia; Zahn, Susann; Aschemann-Witzel, Jessica; Rohm, Harald

    2017-03-01

    Reducing food waste is one of the prominent goals in the current research, which has also been set by the United Nations to achieve a more sustainable world by 2030. Given that previous studies mainly examined causes for food waste generation related to consumers, e.g., expectations regarding quality or uncertainties about edibility, this review aims at providing an overview on losses in the food industry, as well as on natural mechanisms by which impeccable food items are converted into an undesired state. For this, scientific literature was reviewed based on a keyword search, and information not covered was gathered by conducting expert interviews with representatives from 13 German food processing companies. From the available literature, three main areas of food waste generation were identified and discussed: product deterioration and spoilage during logistical operations, by-products from food processing, and consumer perception of quality and safety. In addition, expert interviews revealed causes for food waste in the processing sector, which were categorised as follows: losses resulting from processing operations and quality assurance, and products not fulfilling quality demands from trade. The interviewees explained a number of strategies to minimise food losses, starting with alternative tradeways for second choice items, and ending with emergency power supplies to compensate for power blackouts. It became clear that the concepts are not universally applicable for each company, but the overview provided in the present study may support researchers in finding appropriate solutions for individual cases.

  18. Did Geomagnetic Activity Challenge Electric Power Reliability During Solar Cycle 23? Evidence from the PJM Regional Transmission Organization in North America

    Science.gov (United States)

    Forbes, Kevin F.; Cyr, Chris St

    2012-01-01

    During solar cycle 22, a very intense geomagnetic storm on 13 March 1989 contributed to the collapse of the Hydro-Quebec power system in Canada. This event clearly demonstrated that geomagnetic storms have the potential to lead to blackouts. This paper addresses whether geomagnetic activity challenged power system reliability during solar cycle 23. Operations by PJM Interconnection, LLC (hereafter PJM), a regional transmission organization in North America, are examined over the period 1 April 2002 through 30 April 2004. During this time PJM coordinated the movement of wholesale electricity in all or parts of Delaware, Maryland, New Jersey, Ohio, Pennsylvania, Virginia, West Virginia, and the District of Columbia in the United States. We examine the relationship between a proxy of geomagnetically induced currents (GICs) and a metric of challenged reliability. In this study, GICs are proxied using magnetometer data from a geomagnetic observatory located just outside the PJM control area. The metric of challenged reliability is the incidence of out-of-economic-merit order dispatching due to adverse reactive power conditions. The statistical methods employed make it possible to disentangle the effects of GICs on power system operations from purely terrestrial factors. The results of the analysis indicate that geomagnetic activity can significantly increase the likelihood that the system operator will dispatch generating units based on system stability considerations rather than economic merit.

  19. Modeling and simulation of cascading contingencies

    Science.gov (United States)

    Zhang, Jianfeng

    This dissertation proposes a new approach to model and study cascading contingencies in large power systems. The most important contribution of the work involves the development and validation of a heuristic analytic model to assess the likelihood of cascading contingencies, and the development and validation of a uniform search strategy. We model the probability of cascading contingencies as a function of power flow and power flow changes. Utilizing logistic regression, the proposed model is calibrated using real industry data. This dissertation analyzes random search strategies for Monte Carlo simulations and proposes a new uniform search strategy based on the Metropolis-Hastings Algorithm. The proposed search strategy is capable of selecting the most significant cascading contingencies, and it is capable of constructing an unbiased estimator to provide a measure of system security. This dissertation makes it possible to reasonably quantify system security and justify security operations when economic concerns conflict with reliability concerns in the new competitive power market environment. It can also provide guidance to system operators about actions that may be taken to reduce the risk of major system blackouts. Various applications can be developed to take advantage of the quantitative security measures provided in this dissertation.

  20. Power System Self-organized Criticality Simulation Model Based on Cellular Automata%基于元胞自动机的电力系统自组织临界特性仿真模型

    Institute of Scientific and Technical Information of China (English)

    于群; 曹娜; 郭剑波

    2011-01-01

    将元胞自动机理论应用到电力系统大停电机理研究中,提出并建立了用元胞自动机来模拟电网故障演化的电网故障元胞自动机模型,定义了电网故障元胞自动机模型中元胞、元胞空间、规则和邻居等的构成方法。利用电网故障元胞自动机模型,仿真研究了电网故障的传播演化过程,并对电网故障的自组织临界性(SOC)进行了验证。%By applying the theory of cellular automata in the evolutionary mechanism of the power system blackout,a model for simulating power failure with cellular automata is presented.The model defines the composing method of cells,cellular space,rules,neighbors,etc.The spread and evolution of power failure is investigated using proposed model and the self-organized criticality(SOC) of the power grid failure is verified. This work is supported by State Administration of Work Safety Project(No.10-052) and State Grid Corporation of China.

  1. Optimization Strategies for the Vulnerability Analysis of the Electric Power Grid

    Energy Technology Data Exchange (ETDEWEB)

    Pinar, A.; Meza, J.; Donde, V.; Lesieutre, B.

    2007-11-13

    Identifying small groups of lines, whose removal would cause a severe blackout, is critical for the secure operation of the electric power grid. We show how power grid vulnerability analysis can be studied as a mixed integer nonlinear programming (MINLP) problem. Our analysis reveals a special structure in the formulation that can be exploited to avoid nonlinearity and approximate the original problem as a pure combinatorial problem. The key new observation behind our analysis is the correspondence between the Jacobian matrix (a representation of the feasibility boundary of the equations that describe the flow of power in the network) and the Laplacian matrix in spectral graph theory (a representation of the graph of the power grid). The reduced combinatorial problem is known as the network inhibition problem, for which we present a mixed integer linear programming formulation. Our experiments on benchmark power grids show that the reduced combinatorial model provides an accurate approximation, to enable vulnerability analyses of real-sized problems with more than 10,000 power lines.

  2. Interviewing insights regarding the fatalities inflicted by the 2011 Great East Japan Earthquake

    Directory of Open Access Journals (Sweden)

    M. Ando

    2013-09-01

    Full Text Available One hundred fifty survivors of the 11 March 2011 Great East Japan Earthquake (Tohoku-oki earthquake (Mw = 9.0 were interviewed to study the causes of deaths from the associated tsunami in coastal areas of Tohoku. The first official tsunami warning underestimated the height of the tsunami and 40% of the interviewees did not obtain this warning due to immediate blackouts and a lack of communication after the earthquake. Many chose to remain in dangerous locations based on the underestimated warning and their experiences with previous smaller tsunamis and/or due to misunderstanding the mitigating effects of nearby breakwaters in blocking incoming tsunamis. Some delayed their evacuation to perform family safety checks, and in many situations, the people affected misunderstood the risks involved in tsunamis. In this area, three large tsunamis have struck in the 115 yr preceding the 2011 tsunami. These tsunamis remained in the collective memory of communities, and numerous measures against future tsunami damage, such as breakwaters and tsunami evacuation drills, had been implemented. Despite these preparedness efforts, approximately 18 500 deaths and cases of missing persons occurred. The death rate with the age of 65 and above was particularly high, four times higher than that with other age groups. These interviews indicate that deaths resulted from a variety of reasons, but if residents had taken immediate action after the major ground motion stopped, most residents might have been saved. Education about the science behind earthquakes and tsunamis could help save more lives in the future.

  3. Operation and Maintenance of Overhead Transmission Line%架空输电线路的运行维护

    Institute of Scientific and Technical Information of China (English)

    王刚

    2014-01-01

    架空输电线路是将不同地区的发电厂、变电站、负荷点连接起来,起输送或交换电能作用的线路。由于架空线路暴露在大气环境中,易受到雷电袭击、雨淋、湿雾以及自然和工业污秽等造成停电事故。因此,加强架空输电线路的运行维护具有重要的意义。%Overhead transmission line is connecting the power plant, transformer substation, load point in different regions, designed for conveyance or exchange of electric energy. Bec- ause the overhead line is exposed to the atmosphere, it is often caused blackouts due to lightning, rain, wet fog and natural and industrial polution. Therefore, it is of important significa- nce to strengthen the maintenance operation of overhead tran- smission lines.

  4. Transmission Planning and Investment in the Competitive Environment

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ An important conclusion of the mega-blackout of August 14, 2003 is the fact that the transmission network is the weakest link of the restructured electricity business in the United States. The widespread outage pinpointed the critical need for investment in the improvement and expansion of the grid and for maintaining the existing network. Such a need has failed to be met in the new competitive environment. The restructuring of the electricity industry has resulted in the advent of many new players, the unleashing of competition in the wholesale electricity markets, the unbundling of transmission from the generation and the distribution sectors, the creation of new structures, such as the Independent Transmission Entity (ITE) and the move toward decentralized decision-making. In addition, the creation of this new transmission entity is marked by the separation of the ownership from the control and operation of the network. A fundamental responsibility of the ITE is the provision of nondiscriminatory transmission access and services to all market participants as required under the open access regime introduced with the restructuring. This central role in the evolving wholesale competition in electricity is critical for the operation of vibrant, competitive electricity markets.

  5. Severe accident analysis in a two-loop PWR nuclear power plant with the ASTEC code

    Energy Technology Data Exchange (ETDEWEB)

    Sadek, Sinisa; Amizic, Milan; Grgic, Davor [Zagreb Univ. (Croatia). Faculty of Electrical Engineering and Computing

    2013-12-15

    The ASTEC/V2.0 computer code was used to simulate a hypothetical severe accident sequence in the nuclear power plant Krsko, a 2-loop pressurized water reactor (PWR) plant. ASTEC is an integral code jointly developed by Institut de Radioprotection et de Surete Nucleaire (IRSN, France) and Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS, Germany) to assess nuclear power plant behaviour during a severe accident. The analysis was conducted in 2 steps. First, the steady state calculation was performed in order to confirm the applicability of the plant model and to obtain correct initial conditions for the accident analysis. The second step was the calculation of the station blackout accident with a leakage of the primary coolant through degraded reactor coolant pump seals, which was a small LOCA without makeup capability. Two scenarios were analyzed: one with and one without the auxiliary feedwater (AFW). The latter scenario, without the AFW, resulted in earlier core damage. In both cases, the accident ended with a core melt and a reactor pressure vessel failure with significant release of hydrogen. In addition, results of the ASTEC calculation were compared with results of the RELAP5/SCDAPSIM calculation for the same transient scenario. The results comparison showed a good agreement between predictions of those 2 codes. (orig.)

  6. Random load fluctuations and collapse probability of a power system operating near codimension 1 saddle-node bifurcation

    CERN Document Server

    Podolsky, Dmitry

    2012-01-01

    For a power system operating in the vicinity of the power transfer limit of its transmission system, effect of stochastic fluctuations of power loads can become critical as a sufficiently strong such fluctuation may activate voltage instability and lead to a large scale collapse of the system. Considering the effect of these stochastic fluctuations near a codimension 1 saddle-node bifurcation, we explicitly calculate the autocorrelation function of the state vector and show how its behavior explains the phenomenon of critical slowing-down often observed for power systems on the threshold of blackout. We also estimate the collapse probability/mean clearing time for the power system and construct a new indicator function signaling the proximity to a large scale collapse. The new indicator function is easy to estimate in real time using PMU data feeds as well as SCADA information about fluctuations of power load on the nodes of the power grid. We discuss control strategies leading to the minimization of the coll...

  7. Nature's third cycle a story of sunspots

    CERN Document Server

    Choudhuri, Arnab Rai

    2015-01-01

    The cycle of day and night and the cycle of seasons are two familiar natural cycles around which many human activities are organized. But is there a third natural cycle of importance for us humans? On 13 March 1989, six million people in Canada went without electricity for many hours: a large explosion on the sun was discovered as the cause of this blackout. Such explosions occur above sunspots, dark features on the surface of the Sun that have been observed through telescopes since the time of Galileo. The number of sunspots has been found to wax and wane over a period of 11 years. Although this cycle was discovered less than two centuries ago, it is becoming increasingly important for us as human society becomes more dependent on technology. For nearly a century after its discovery, the cause of the sunspot cycle remained completely shrouded in mystery. The 1908 discovery of strong magnetic fields in sunspots made it clear that the 11-year cycle is the magnetic cycle of the sun. It is only during the last ...

  8. The insulation coordination and surge arrester design for HTS cable system in Icheon substation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hansang, E-mail: Hansang80@korea.ac.kr [School of Railway and Electrical Engineering, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Yoon, Dong-Hee [Department of New and Renewable Energy, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Lee, Seung-Ryul [Korea Electrotechnology Research Institute, Naeson-dong, Uiwang-si, Gyeonggi-do 437-080 (Korea, Republic of); Yang, Byeong-Mo [Korea Electric Power Research Institute, Munji-dong, Yuseong-gu, Daejeon 305-760 (Korea, Republic of); Jang, Gilsoo, E-mail: gjang@korea.ac.kr [School of Electrical Engineering, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-713 (Korea, Republic of)

    2013-01-15

    Highlights: ► It is necessary to study lightning response of the HTS cable. ► The analytic model has been developed for the HTS cable in the Icheon substation. ► Well-designed surge arrester has been verified through PSCAD/EMTDC simulations. -- Abstract: This paper proposes an insulation coordination and surge arrester design for HTS (High-Temperature Superconducting) cable system in Icheon substation in Korea. In the aspect of the economic analysis, since the HTS cable is very expensive, the insulation coordination to prevent the dielectric breakdown caused by the lightning surge should be considered carefully. Also, in the aspect of the power system reliability, since the HTS cable has much more capacity compared than conventional power cables and the ripple effect from the HTS cable failure may lead to the wide area blackout, an intensive study for insulation coordination from lightning surge is one of the most important considerations. In this paper, the insulation coordination for lightning surge is verified using HTS cable and power equipment models and the design of the proper surge arrester is proposed.

  9. Technological status of reactor coolant pumps in generation III+ pressurized nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Brecht, Bernhard; Bross, Stephan [KSB Aktiengesellschaft, Frankenthal (Germany)

    2016-05-15

    KSB has been developing and producing pumps for thermal power plants for nearly 90 years. Consequently, KSB also started to develop and manufacture pumps for all kinds of nuclear power plants from the very beginning of the civil use of nuclear energy. This is especially true for reactor coolant pumps for pressurized water reactors. For the generation of advanced evolutionary reactors (Generation III+ reactors), KSB developed an advanced shaft seal system which is also able to fulfill the requirements of station blackout conditions. The tests in the KSB test rigs, which were successfully completed in December 2015, proved the full functionality of the new design. For generation III+ passive plant reactors KSB developed a new reactor coolant pump type called RUV, which is based on the experience of classic reactor coolant pumps and reactor internal pumps. It is a very compact, hermetically sealed vertical pump-motor unit with a wet winding motor. A full scale prototype successfully passed the 1st stage qualification test program in October 2015.

  10. Trait-based affective processes in alcohol-involved "risk behaviors".

    Science.gov (United States)

    Wray, Tyler B; Simons, Jeffrey S; Dvorak, Robert D; Gaher, Raluca M

    2012-11-01

    This study tested a theoretical model of alcohol use, markers of extreme intoxication, and risk behavior as a function of trait affect, distress tolerance, and affect-based behavior dysregulation. Positive affective pathways to risk behavior were primarily expected to be indirect via high levels of alcohol use, while negative affect paths were expected to be more directly associated with engagement in risk behavior. In addition, we expected trait affectivity and distress tolerance would primarily exhibit relationships with alcohol use and problems through behavioral dysregulation occurring during extreme affective states. To evaluate these hypotheses, we tested a SEM with three alcohol-related outcomes: "Typical" alcohol use, "blackout" drinking, and risk behavior. High trait negative affect and low tolerance for affective distress contribute to difficulty controlling behavior when negatively aroused and this is directly associated with increased risk behavior when drinking. In contrast, associations between positive urgency and risk behaviors are indirect via increased alcohol consumption. Positive affectivity exhibited both inverse and positive effects in the model, with the net effect on alcohol outcomes being insignificant. These findings contribute important information about the distinct pathways between affect, alcohol use, and alcohol-involved risk behavior among college students.

  11. Adaptive load forecasting of the Hellenic electric grid

    Institute of Scientific and Technical Information of China (English)

    S. Sp. PAPPAS; L. EKONOMOU; V. C. MOUSSAS; P. KARAMPELAS; S. K. KATSIKAS

    2008-01-01

    Designers are required to plan for future expansion and also to estimate the grid's future utilization. This means that an effective modeling and forecasting technique,which will use efficiently the information contained in the available data,is required,so that important data properties can be extracted and projected into the future. This study proposes an adaptive method based on the multi-model partitioning algorithm (MMPA),for short-term electricity load forecasting using real data. The grid's utilization is initially modeled using a multiplicative seasonal ARIMA (autoregressive integrated moving average) model. The proposed method uses past data to learn and model the normal periodic behavior of the electric grid. Either ARMA (autoregressive moving average) or state-space models can be used for the load pattern modeling. Load anomalies such as unexpected peaks that may appear during the summer or unexpected faults (blackouts) are also modeled. If the load pattern does not match the normal be-havior of the load,an anomaly is detected and,furthermore,when the pattern matches a known case of anomaly,the type of anomaly is identified. Real data were used and real cases were tested based on the measurement loads of the Hellenic Public Power Cooperation S.A.,Athens,Greece. The applied adaptive multi-model filtering algorithm identifies successfully both normal periodic behavior and any unusual activity of the electric grid. The performance of the proposed method is also compared to that produced by the ARIMA model.

  12. Multiagents-based wide area protection with best-effort adaptive strategy

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yongli; Wang, Dewen [North China Electric Power University, Baoding (China); Song, Shaoqun [Fuzhou Electric Power Industry Bureau, Fujian Province (China)

    2009-02-15

    Abstract - Multi-trips of circuit breakers often occur within a short period in a severe blackout, and the tripping usually relates to relays' mal-operations. In fact, when two ore more electric primary devices are isolated by circuit breakers, the settings of most relays to protect their power system are getting infeasible and uncoordinated. Adaptive settings are needed to prevent them from wrong operation. This paper presents an adaptive protection scheme based on wide area information with best-effort protection strategy, and the outline of multiagents and WAN Based Adaptive Protection System (MAWAPS). In the scheme, the best-effort adaptive strategy is used to guarantee the adaptive settings to operate safely and effectively in most situations. The IP/SDH-based wide area network (WAN) is used to realize real-time wide area information exchange in the proposed protection scheme. Adaptive setting algorithms for the second stage zero-sequence current and phase overcurrent relays are proposed, which can provide larger line coverage than traditional relays. Moreover, multiagent techniques and IEC 61850 are employed to realize the fast communication between different agents, and MMS plays a prominent role in real-time remote communication. A simulating system has been developed according to the above ideas and approaches, and the experimental results show that the proposed adaptive protection scheme is feasible from the view of protective performance including the executing time. (author)

  13. Performance Comparison of Voltage Stability Indices for Weak Bus Identification in Power Systems

    Science.gov (United States)

    Verayiah, R.; Mohamed, A.; Shareef, H.; Zainal Abidin, I. Hj

    2013-06-01

    Voltage collapse event is identified as complex and localized in nature but its effect is extensive once occurred. The vital effect of voltage collapse would be the total system collapse or blackouts which would cost a large loss to utility companies. Eventually, on- line monitoring of power system stability has become an important factor for electric power utilities. The last utmost option to avert voltage collapse incident from occurring is by the implementation of under voltage load shedding scheme. The identification of location for load shedding is the main motivation of the study. The weakest bus in a power system is identified as the location for load shedding. This location is obtained using voltage stability index Ld. The performance and effectiveness of Ld index is compared with Fast Voltage Stability Index (FVSI) and Le Index. The results obtained indicate that Ld Index can be used to identify the weak bus in a power system and consequently for the placement of UVLS relays in a power system network.

  14. Alternative Approaches for Incentivizing the Frequency Responsive Reserve Ancillary Service

    Energy Technology Data Exchange (ETDEWEB)

    Ela, E.; Milligan, M.; Kirby, B.; Tuohy, A.; Brooks, D.

    2012-03-01

    Frequency responsive reserve is the autonomous response of generators and demand response to deviations of system frequency, usually as a result of the instantaneous outage of a large supplier. Frequency responsive reserve arrests the frequency decline resulting in the stabilization of system frequency, and avoids the triggering of under-frequency load-shedding or the reaching of unstable frequencies that could ultimately lead to system blackouts. It is a crucial service required to maintain a reliable and secure power system. Regions with restructured electricity markets have historically had a lack of incentives for frequency responsive reserve because generators inherently provided the response and on large interconnected systems, more than sufficient response has been available. This may not be the case in future systems due to new technologies and declining response. This paper discusses the issues that can occur without proper incentives and even disincentives, and proposes alternatives to introduce incentives for resources to provide frequency responsive reserve to ensure an efficient and reliable power system.

  15. An Integrated Framework For Power And ICT System Risk-Based Security Assessment

    Directory of Open Access Journals (Sweden)

    Emanuele Ciapessoni*,

    2014-01-01

    Full Text Available Power system (PS is exposed to natural and man-related threats which may affect the security of power supply, depending on the vulnerabilities of the system to the threats themselves as well as on the pre-fault operating conditions. Threats regard not only the power components, but also the Information and Communications Technology (ICT systems involved in PS control and protection. The resulting picture is characterized by significant uncertainties, especially as far as high impact, low probability (HILP events (typical causes of blackout events are concerned. These considerations call for the adoption of novel techniques to perform more in-depth security analyses, able to identify the contributions of the different threats and vulnerabilities to the overall operational risk. The paper describes a probabilistic risk-based methodology, developed within the European Union (EU research project AFTER (A Framework for electrical power sysTems vulnerability identification, dEfense and Restoration, aiming to perform risk assessment (by means of hazard, vulnerability, and impact analysis of the integrated power and ICT systems. Initial results of the approach are described with reference to a test system.

  16. Computing Earthquake Probabilities on Global Scales

    Science.gov (United States)

    Holliday, James R.; Graves, William R.; Rundle, John B.; Turcotte, Donald L.

    2016-03-01

    Large devastating events in systems such as earthquakes, typhoons, market crashes, electricity grid blackouts, floods, droughts, wars and conflicts, and landslides can be unexpected and devastating. Events in many of these systems display frequency-size statistics that are power laws. Previously, we presented a new method for calculating probabilities for large events in systems such as these. This method counts the number of small events since the last large event and then converts this count into a probability by using a Weibull probability law. We applied this method to the calculation of large earthquake probabilities in California-Nevada, USA. In that study, we considered a fixed geographic region and assumed that all earthquakes within that region, large magnitudes as well as small, were perfectly correlated. In the present article, we extend this model to systems in which the events have a finite correlation length. We modify our previous results by employing the correlation function for near mean field systems having long-range interactions, an example of which is earthquakes and elastic interactions. We then construct an application of the method and show examples of computed earthquake probabilities.

  17. Impacts of Natural Disasters on Swedish Electric Power Policy: A Case Study

    Directory of Open Access Journals (Sweden)

    Niyazi Gündüz

    2017-02-01

    Full Text Available The future of climate and sustainable energy are interrelated. Speaking of one without mentioning the other is quite difficult. The increasing number of natural disasters pose a great threat to the electric power supply security in any part of the world. Sweden has been one of the countries that have suffered from unacceptably long blackouts. The tremendous outcomes of the power interruptions have made the field of the economic worth of electric power reliability a popular area of interest among researchers. Nature has been the number one enemy against the supply security of the electricity. This paper introduces a recent and thorough electric power reliability analysis of Sweden and focuses on the country’s struggle against climate change-related natural disasters via updating the country’s electric power policy to improve its service quality. The paper highlights the Gudrun storm of 2005 as a case study to demonstrate the severe impacts of extreme weather events on the energy systems. The economic damage of the storm on the electric power service calculated to be around 3 billion euros.

  18. MELCOR 1.8.2 assessment: Surry PWR TMLB` (with a DCH study)

    Energy Technology Data Exchange (ETDEWEB)

    Kmetyk, L.N.; Cole, R.K. Jr.; Smith, R.C.; Summers, R.M.; Thompson, S.L.

    1994-02-01

    MELCOR is a fully integrated, engineering-level computer code, being developed at Sandia National Laboratories for the USNRC. This code models the entire spectrum of severe accident phenomena in a unified framework for both BWRs and PWRs. As part of an ongoing assessment program, the MELCOR computer code has been used to analyze a station blackout transient in Surry, a three-loop Westinghouse PWR. Basecase results obtained with MELCOR 1.8.2 are presented, and compared to earlier results for the same transient calculated using MELCOR 1.8.1. The effects of new models added in MELCOR 1.8.2 (in particular, hydrodynamic interfacial momentum exchange, core debris radial relocation and core material eutectics, CORSOR-Booth fission product release, high-pressure melt ejection and direct containment heating) are investigated individually in sensitivity studies. The progress in reducing numeric effects in MELCOR 1.8.2, compared to MELCOR 1.8.1, is evaluated in both machine-dependency and time-step studies; some remaining sources of numeric dependencies (valve cycling, material relocation and hydrogen burn) are identified.

  19. Introduction to Urban-villages Electricity Problems and Solving Measures%浅谈城中村用电困局及解决措施

    Institute of Scientific and Technical Information of China (English)

    陈泰霖

    2015-01-01

    随着城市的迅猛发展,大量外来人口迁入各地城中村,导致城中村用电负荷暴增,残旧的城中村电网以及各种违法用电行为使得城中村用电陷入频繁停电的困局。该文通过对城中村用电现状的描述,分析造成用电困局的原因,并在此基础上提出破解城中村用电困局的若干建议。%A large number of floating population move into the urban-village, with the rapid development of the city, which then lead to the explosive growth in electrical loads power of the urban-village. Klunky power grid of the urban-village, and various illegal electricity utilization behavior make urban-villages go into the dilemma of frequent blackouts. This paper offers some suggestions about the urban-villages electricity dilemma, which is based on the description about the present situation of urban-villages electricity and analyzing the cause of electricity dilemma.

  20. HARDRONIC 2011

    CERN Multimedia

    2011-01-01

      This year’s world-famous Hardronic Festival will take place on Friday 22nd July and Saturday 23rd July on the terrace behind restaurant 3 at Prevessin. There will be lots of live music from all your favourite CERN bands plus food, drink on both days with stuff for kids to do on Saturday. So, if you have not got your ticket for Montreux or Paleo, put the dates in your diaries and spend the weekend listening to some great live music (and, unlike Paleo and Montreux, it’s FREE!!!!) Things get started at 17h30 on both days and the program is as follows: Friday 22 July 17h30 – Hadron/JamBand 19h00 - Tony Arnold 20h00 - Blend 21h00 - The Canettes 22h00 - Miss Proper 23h00 - Shocking Pink 24h00 - D'ANGLERZ Saturday 23 July 17h30 – Hadron/JamBand 18h00 - Malavida (provisional) 19h00 - Awesome 20h00 - The Tape Trade 21h00 - Data?Fail! 22h00 - Sour Hurricane 23h00 - Physt 24h00 - Total Blackout For more information on the CERN MusiClub see http://muzipod...

  1. The natural gas in Brazil and the future challenges of the energy sector; O gas natural no Brasil e os futuros desafios do setor energetico

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Sirlei A. de [Centro de Tecnologia Mineral (CETEM), Rio de Janeiro, RJ (Brazil); Favera, Jorge C. Della; Medeiros, Marco Andre M. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

    2008-07-01

    The theme Energy should be analyzed under the light of the environmental sustainability, because this subject takes force all over and it could not be different in Brazil, where new projects are only approved after exhausting discussions inside the Ministry of Mines and Energy/MME, Ministry of Science and Technology/MCT and mainly the Ministry of Environment. It is an unquestionable fact that the generation of brazilian energy is structured on the hydric electricity, that due to readiness of great amount of hydric resources, meantime with the economical development of the country there is need to produce more energy, but it is not possible due the exhaustion of rivers with great load, being essential the research for the development other options in energy sources, under the risk of the economy to enter in collapse as it happened few years ago, with the electrical blackout. Due to the current situation, a participation every time larger of the natural gas is expected at the brazilian energetic system, once this energy staff appears as much as substitute the electric power (in some uses as the heating, heating of water, industrial ovens, etc) and as fuel for the generation of energy (UTE's, GNV). Next years can be decisive for the Brazilian economy. (author)

  2. The Spanish Space Weather Service SeNMEs. A Case Study on the Sun-Earth Chain

    Science.gov (United States)

    Palacios, J.; Cid, C.; Guerrero, A.; Saiz, E.; Cerrato, Y.; Rodríguez-Bouza, M.; Rodríguez-Bilbao, I.; Herraiz, M.; Rodríguez-Caderot, G.

    2016-04-01

    The Spanish Space Weather Service SeNMEs, www.senmes.es, is a portal created by the SRG-SW of the Universidad de Alcalá, Spain, to meet societal needs of near real-time space weather services. This webpage-portal is divided in different sections to fulfill users needs about space weather effects: radio blackouts, solar energetic particle events, geomagnetic storms and presence of geomagnetically induced currents. In less than one year of activity, this service has released a daily report concerning the solar current status and interplanetary medium, informing about the chances of a solar perturbation to hit the Earth's environment. There are also two different forecasting tools for geomagnetic storms, and a daily ionospheric map. These tools allow us to nowcast a variety of solar eruptive events and forecast geomagnetic storms and their recovery, including a new local geomagnetic index, LDiñ, along with some specific new scaling. In this paper we also include a case study analysed by SeNMEs. Using different high resolution and cadence data from space-borne solar telescopes SDO, SOHO and GOES, along with ionospheric and geomagnetic data, we describe the Sun-Earth feature chain for the event.

  3. Continuing California drought: an assessment of its effect on past and future energy production

    Energy Technology Data Exchange (ETDEWEB)

    1977-10-01

    The two successive dry years have severely impacted California's electrical utilities, and have caused them to make some major operating changes in order to provide adequate supplies of energy to meet their customer's demands. The following information describes the impact that two years of drought has had on the generating capabilities of the electric utilities in California, the contingency measures that have been taken, the minor events which have occasionally resulted in unusually low electrical reserve capacity margins, and what can be expected during 1978, should the drought continue. The staff of the Energy Commission conclude that by treating the entire state as a whole rather than by individual service areas, doing everything possible to maximize generation, and facilitating the transfer of power to areas of greatest need, that the State of California can withstand the threat of rolling blackouts, under the adverse conditions, without undue loss of income or substantial threat to the public health or safety. A continued drought will severely test the resources of the state's electrical utilities, and unusually high forced outage levels could conceivable create situations where occasional preplanned outages could result. However, increased conservation practices, proper advanced planning, complete cooperation between all utilities, and the maximum utilization of all generation resources, as recommended, should create a manageable situation in 1978.

  4. No.7欧洲配电网智能化发展中的规划技术%NO.7 Planning Technology in the Intelligent Development of European Distribution Networks

    Institute of Scientific and Technical Information of China (English)

    范明天; 惠慧; 刘蒙; 张毅威; 张祖平

    2015-01-01

    Main issues and challenges involved in the intelligent development of the European distribution networks are discussed.Firstly,the impact of energy policy on distribution network planning is analyzed.Secondly,the influence of the smart grid technology on long term load forecasting is discussed,including the influence of the user gateway and the behaviors of electricity customerson load and energy forecasting.Then,the various elements of the distribution network planningare analyzed,and the objective,cost,basic conditions,and boundary conditionsof planningare summarized,and a variety of tasks and the relationship among them in the process of the distribution network developmentare introduced. Meanwhile,the influence of new technologies(such as LVDC,energy storage,automation and cabling)on the planning are discussed,and the economic comparison method of the planning is illustrated through an energy storage case.Finally,the paper explains the impact of the new regulation mode of power supply reliability(regulating the long term blackout instead of the short term blackout)on the planning.It is emphasized that the strategies adapting to the distribution network development should be drew up to cope with the uncertainty of the policy,the load and the electrical technologydevelopment.China will face the same situationin the future development of active distribution networks.%探讨配电网智能化发展过程中规划涉及的各种要素及面临的挑战。首先分析了能源政策对电网规划的影响,其次分析了智能电网技术对长期负荷预测的影响,其中简要介绍了一种用户网关新技术,并分析了各种用电行为对负荷和电量预测的影响程度。接着分析了配电网规划的各种要素,归纳了规划的目标、费用、基础条件以及边界条件,并介绍了网络发展过程中的各种任务及其相互关系。同时介绍了新技术(如LVDC、储能、自动化、电缆化)对规划的影响,

  5. Attacker’s Perspective Based Analysis on Cyber Attack Mode to Cyber-Physical System%基于攻击方视角的电力CPS网络攻击模式分析

    Institute of Scientific and Technical Information of China (English)

    苏盛; 吴长江; 马钧; 曾祥君

    2014-01-01

    电力信息物理系统(cyber-physical system,CPS)中,电力系统的调度控制和生产管理高度依赖于信息系统,是网络攻击的高价值目标。鉴于攻击方选取的攻击模式和对象因目的不同而有明显差异,文章将对电力 CPS 的网络攻击分为无特定目的、以获取经济利益为目的、以破坏电网稳定为目的3类,分别进行了讨论。首先结合北美电网信息系统相关大停电分析了无特定目的网络攻击和信息系统自身随机失效与异常对电网的影响;然后综述了谋求经济利益的攻击中窃电行为检测方法;最后,假定以破坏电网稳定为目的的恶意软件能借用震网病毒传播模式侵入实时控制区,结合我国与北美电力企业在 SCADA 系统和广域保护等系统应用上存在的差异,分析了攻击方可能选择的攻击对象、攻击模式和后果,讨论了智能电表和SCADA中的针对性入侵检测方法。%In modern power grid the dispatching and control as well as the production management heavily rely on the electrical cyber-physical system (CPS). Consequently, the electric CPS becomes a high value target of cyber attack. Since there are obvious differences among attack objects due to the different aims of the attack, the adopted attack patterns are different, herein the cyber attacks in electrical CPS are classified into three categories, i.e., having no specific aim, getting economic benefit and destroying power grid stability such as leading to catastrophic blackout, and discussed respectively. Firstly, based on the collected data related to blackouts in North America from 2003 to 2007, the impacts of the cyber attack without special aim and the random failure and anomaly of cyber system itself on power grid are analyzed;then the methods to detect the electricity theft by the cyber attack to seek economic interests are summarized; finally, assuming that the malware, whose purpose is to collapse power

  6. 基于电网分区的负荷恢复智能优化策略%Intelligent optimization strategy for load restoration considering power grid partitioning

    Institute of Scientific and Technical Information of China (English)

    石立宝; 赤东阳; 姚良忠; 倪以信; Masoud Bazargan

    2011-01-01

    In this paper, an intelligent optimization strategy for load restoration after power system blackout considering system-partitioning is presented. First of all, an optimal system-partitioning strategy for system recovery after blackout is proposed. Some influence factors involving the charging Mvar of overhead transmission lines for generator restoration, the closing operation times of transmission lines for load restoration are considered during modeling. With respect to the result of optimal system-partitioning, a unified load restoration optimization model taking into account network reconfiguration is built to realize the parallel recovery of each partition. The genetic algorithm (GA) and the traditional graph theory are combined to solve the proposed optimization models described above. Some improvements including stochastic load shedding and the shortest path repair strategies against the problem of a large number of infeasible solutions generated by utilizing the traditional genetic algorithm are made to improve the computational efficiency and the performance of global optimization of GA further during optimization. Finally, the case studies are carried out based on the IEEE-30 test system to demonstrate the effectiveness and validity of the proposed models and methods. This work is supported by National Natural Science Foundation of China (No. 50977051).%针对电力系统大停电后的负荷快速恢复问题,提出了一种基于电网分区的负荷恢复智能优化策略.提出了一种大停电事故后系统恢复的最优分区策略,并在所建立的优化模型中考虑了为恢复发电机而引入的架空线路充电无功以及为恢复负荷所引入的线路合闸操作次数等影响因素.在完成对大规模系统优化分区后,对各分区建立了一个统一的并计及网络重构因素的负荷恢复优化模型,实现各分区负荷的并行恢复.针对上述所提出的优化模型,通过结合传统图论理论和遗传算

  7. Severe Accident Scoping Simulations of Accident Tolerant Fuel Concepts for BWRs

    Energy Technology Data Exchange (ETDEWEB)

    Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-01

    Accident-tolerant fuels (ATFs) are fuels and/or cladding that, in comparison with the standard uranium dioxide Zircaloy system, can tolerate loss of active cooling in the core for a considerably longer time period while maintaining or improving the fuel performance during normal operations [1]. It is important to note that the currently used uranium dioxide Zircaloy fuel system tolerates design basis accidents (and anticipated operational occurrences and normal operation) as prescribed by the US Nuclear Regulatory Commission. Previously, preliminary simulations of the plant response have been performed under a range of accident scenarios using various ATF cladding concepts and fully ceramic microencapsulated fuel. Design basis loss of coolant accidents (LOCAs) and station blackout (SBO) severe accidents were analyzed at Oak Ridge National Laboratory (ORNL) for boiling water reactors (BWRs) [2]. Researchers have investigated the effects of thermal conductivity on design basis accidents [3], investigated silicon carbide (SiC) cladding [4], as well as the effects of ATF concepts on the late stage accident progression [5]. These preliminary analyses were performed to provide initial insight into the possible improvements that ATF concepts could provide and to identify issues with respect to modeling ATF concepts. More recently, preliminary analyses for a range of ATF concepts have been evaluated internationally for LOCA and severe accident scenarios for the Chinese CPR1000 [6] and the South Korean OPR-1000 [7] pressurized water reactors (PWRs). In addition to these scoping studies, a common methodology and set of performance metrics were developed to compare and support prioritizing ATF concepts [8]. A proposed ATF concept is based on iron-chromium-aluminum alloys (FeCrAl) [9]. With respect to enhancing accident tolerance, FeCrAl alloys have substantially slower oxidation kinetics compared to the zirconium alloys typically employed. During a severe accident, Fe

  8. Handling of crisis situations in the electric power system; Krishantering i elsystemet. Elnaetbolags, kommuners och hushaalls uppfattningar om roller och ansvarsfoerdelning vid elavbrott

    Energy Technology Data Exchange (ETDEWEB)

    Palm, Jenny (Linkoepnig Univ., Linkoeping (SE). Dept. of Technology and Social Change)

    2007-12-15

    In this report municipalities, grid companies and electricity users' relations and responsibilities are discussed in connection to the actors experience during two storms named Per and Gudrun. Special focus is on households' action space, that is possibilities and constrains to uphold every day routines during outages. The material consists of case studies in Oestergoetland, involving a survey to households, interviews and participating observations. The theoretical perspective used is Karl Poppers' three worlds related to everyday life. World 1 is the physical and material world; World 2 consists of people's perception and ideas and World 3 is the cultural and social world. In world 1 is the importance of information and communication as well as spare power supply capacity discussed. Municipalities and grid companies emphasise Internet as an important communication tool. For the users the phone was the most important tool used during black-outs. One problem was however to get in contact with the energy company because of the overload on the companies' switchboard. Both the municipalities and the energy companies meant that they had enough spare power supply capacity. Around one third of the households said they had a portable generator to use during long lasting power outages. In relation to World 2 most households said that 12-24 hours power outages was acceptable, then the problems start for the households and they try to inform themselves of how long the outage will last. But some households never felt the need to contact anyone and they expressed a trust to the grid companies' competence to deal with the problems causing the outage. All actors state that the municipalities have a social responsibility to their citizens and must ensure that they do not suffer during outages. The grid companies' responsibilities according to the actors are to prevent power outages, repair damages and give the customers economical compensations

  9. 计及重要负荷优先恢复的局部电力系统恢复策略%A Restoration Strategy for A Local Power System Considering Critical Load Pickup

    Institute of Scientific and Technical Information of China (English)

    刘伟佳; 林振智; 文福拴; 薛禹胜; 孙维真; 王超

    2013-01-01

    Local outages in a power system are more likely to occur compared with a system wide blackout.However,most existing research is focused on developing restoration strategies for a global blackout in a power system,and less attention has been paid to local power system restoration which occurs more frequently.Given this background,a local power system restoration strategy considering critical load pickups is presented.Firstly,the characteristics of local power system restoration are discussed,and restoration paths are generated based on the topology of the outage area.Secondly,the restoration paths causing over-voltage problems as well as the unnecessary paths are removed.Then,an optimization model is developed for determining restoration subsystems and restoration paths.Compared with most of the existing methods in which subjective weights are required for the lines and buses to be restored,the proposed method can attain more reasonable restoration strategies.Finally,the modified New England system is employed to demonstrate the effectiveness of the developed method.%与全系统大停电事故相比,局部电力系统停电事故发生得更为频繁.现有的研究大多集中于整个电力系统发生停电后的系统恢复问题,而对局部电力系统恢复问题的研究则相对较少.在此背景下,文中提出了考虑重要负荷恢复的局部电力系统恢复策略.考虑到局部电力系统恢复的特点,首先根据局部停电区域的网络拓扑生成恢复路径集,之后对线路过电压和不必要的恢复路径进行判断和筛选,最后在考虑系统非停电区域的传输能力约束和停电区域内部的负荷特性基础上,对局部停电区域恢复的子系统进行划分并对恢复路径进行优化,最终建立了相应的局部电力系统恢复的优化模型.与现有方法一般需要对线路和节点赋予权重不同,所提出的恢复策略基于客观信息,因而可以得到更为合理的优化结果.最后,

  10. Brittleness Source Identification Model for Cascading Failure of Complex Power Grid Based on Brittle Risk Entropy%基于脆性风险熵的复杂电网连锁故障脆性源辨识模型

    Institute of Scientific and Technical Information of China (English)

    刘文颖; 王佳明; 谢昶; 王维洲

    2012-01-01

    The essence of cascading failure in complex power system, which is the main reason of large-scale blackouts, is brittleness process when the brittleness source is excited. To study how large-scale blackouts take place and the defense measures, meanwhile, find out the high-risk lines, the author proposed a brittleness source identification model for cascading failure based on brittleness theory of complex system. From the view that brittleness is the nature of power system, the model used power flow entropy to measure the condition of power grid, and analyzed the mechanism of cascading failure by brittleness relevance and entropy increase from component and macroscopic aspects respectively. Take the identifying method of brittleness sources and brittleness relevance degree of grid components into consideration, a determining process of high-risk lines was given. Through simulation of cascading failure, brittle risk entropy was applied to assess the impact of component outage from power grid operation and the load removed, and this can provide a basis for defensive strategy making. Taking Gansu power network as an example, the feasibility and effectiveness of the proposed defense model were validated.%复杂电网连锁故障是引发系统大停电的主要原因,其实质是脆性源被激发后系统脆性的传播过程.为研究复杂电网大停电的机理及防御措施,同时找出电网的薄弱环节,提出了一种基于复杂系统脆性理论的连锁故障脆性源辨识模型.模型从电力系统本身具有的脆性出发,用潮流熵来衡量电网所处的状态,通过脆性关联及熵增分别从元件和宏观上阐述连锁故障的传播机理.提出了脆性源的辨识方法,并综合元件脆性关联度的分析给出了对连锁故障影响较大的系统薄弱环节的判定流程,通过对连锁故障过程的模拟,用脆性风险熵来评估元件退出运行对电网状态的影响及造成的负荷切除,为连锁故障防御策

  11. Álcool e adolescentes: estudo para implementar políticas municipais Alcohol and adolescents: study to implement municipal policies

    Directory of Open Access Journals (Sweden)

    Denise Leite Vieira

    2007-06-01

    Full Text Available OBJETIVO: Traçar um perfil de estudantes em relação ao consumo de álcool e comportamentos de risco. MÉTODOS: Participaram do estudo 1.990 alunos, com idade entre 11 e 21 anos, de ambos os sexos, matriculados em escolas públicas e privadas de Paulínia, SP, 2004. Um questionário de auto-preenchimento foi respondido em sala de aula, sem a presença do professor. Analisou-se a percepç��o da disponibilidade e facilidade de acesso às bebidas alcoólicas, contexto do beber e conseqüências do consumo. RESULTADOS: A prevalência de uso de álcool na vida foi de 62,2%. Em relação aos últimos 30 dias, 17,3% dos alunos relataram pelo menos um episódio de abuso agudo. Os adolescentes reportaram que adquiram facilmente bebidas alcoólicas de estabelecimentos comerciais e também em contextos sociais com parentes e amigos. Apenas 1% dos menores de idade relatou que tentou, mas não conseguiu comprar bebida alcoólica. Como conseqüências negativas do consumo nos últimos 12 meses, os estudantes relataram ter passado mal por ter bebido (17,9%, arrependimento por algo que fizeram sob o efeito do álcool (11%, blackout (9,8% e ter brigado após beber (5%. Mais da metade (55% dos estudantes conhecia alguém que sofreu acidente de trânsito provocado por motorista embriagado. CONCLUSÕES: Os dados revelaram alta prevalência de consumo de álcool entre os adolescentes estudados e fácil acesso às bebidas alcoólicas, inclusive por menores de idade. Os jovens se colocaram em risco e apresentaram conseqüências negativas do consumo de álcool. Há necessidade de ações imediatas em relação às políticas públicas para o consumo de álcool no Brasil.OBJECTIVE: To build students' profile regarding alcohol consumption and risk behavior. METHODS: A total of 1,990 students were included in the study, aged 11 to 21 years old, from both genders, enrolled in public and private schools, in Southeastern Brazil, in 2004. A self

  12. Third Generation Flywheels for electric storage

    Energy Technology Data Exchange (ETDEWEB)

    Ricci, Michael, R.; Fiske, O. James

    2008-02-29

    Electricity is critical to our economy, but growth in demand has saturated the power grid causing instability and blackouts. The economic penalty due to lost productivity in the US exceeds $100 billion per year. Opposition to new transmission lines and power plants, environmental restrictions, and an expected $100 billion grid upgrade cost have slowed system improvements. Flywheel electricity storage could provide a more economical, environmentally benign alternative and slash economic losses if units could be scaled up in a cost effective manner to much larger power and capacity than the present maximum of a few hundred kW and a few kWh per flywheel. The goal of this project is to design, construct, and demonstrate a small-scale third generation electricity storage flywheel using a revolutionary architecture scalable to megawatt-hours per unit. First generation flywheels are built from bulk materials such as steel and provide inertia to smooth the motion of mechanical devices such as engines. They can be scaled up to tens of tons or more, but have relatively low energy storage density. Second generation flywheels use similar designs but are fabricated with composite materials such as carbon fiber and epoxy. They are capable of much higher energy storage density but cannot economically be built larger than a few kWh of storage capacity due to structural and stability limitations. LaunchPoint is developing a third generation flywheel — the "Power Ring" — with energy densities as high or higher than second generation flywheels and a totally new architecture scalable to enormous sizes. Electricity storage capacities exceeding 5 megawatt-hours per unit appear both technically feasible and economically attractive. Our design uses a new class of magnetic bearing – a radial gap “shear-force levitator” – that we discovered and patented, and a thin-walled composite hoop rotated at high speed to store kinetic energy. One immediate application is power grid

  13. A Systematic Approach to Setting Underfrequency Relays in Electric Power Systems

    Science.gov (United States)

    Qadri, Syed Saadat

    Generation loss contingencies in electric power systems result in a deviation of system frequency from nominal, a condition which must be corrected promptly in order to prevent further degradation of the power system. Automatic load-shedding using underfrequency relays is one of the techniques used to correct abnormal frequency deviations and prevent the risk of uncontrolled outages. If sufficient load is shed following a contingency to preserve interconnections and keep generators on-line, the system can be restored with relative speed and ease. On the other hand, if a declining frequency condition is not dealt with adequately, a cascading disconnection of generating units may develop, leading to a possible total system blackout. This thesis develops and tests a new systematic method for setting underfrequency relays offering a number of advantages over conventional methods. A discretized swing equation model is used to evaluate the system frequency following a contingency, and the operational logic of an underfrequency relay is modeled using mixed integer linear programming (MILP) techniques. The proposed approach computes relay settings with respect to a subset of all plausible contingencies for a given system. A method for selecting the subset of contingencies for inclusion in the MILP is presented. The goal of this thesis is to demonstrate that given certain types of degrees of freedom in the relay setting problem, it is possible to obtain a set of relay settings that limits damage or disconnection of generating units for each and every possible generation loss outage in a given system, while attempting to shed the least amount of load for each contingency.

  14. Network Science Based Quantification of Resilience Demonstrated on the Indian Railways Network.

    Directory of Open Access Journals (Sweden)

    Udit Bhatia

    Full Text Available The structure, interdependence, and fragility of systems ranging from power-grids and transportation to ecology, climate, biology and even human communities and the Internet have been examined through network science. While response to perturbations has been quantified, recovery strategies for perturbed networks have usually been either discussed conceptually or through anecdotal case studies. Here we develop a network science based quantitative framework for measuring, comparing and interpreting hazard responses as well as recovery strategies. The framework, motivated by the recently proposed temporal resilience paradigm, is demonstrated with the Indian Railways Network. Simulations inspired by the 2004 Indian Ocean Tsunami and the 2012 North Indian blackout as well as a cyber-physical attack scenario illustrate hazard responses and effectiveness of proposed recovery strategies. Multiple metrics are used to generate various recovery strategies, which are simply sequences in which system components should be recovered after a disruption. Quantitative evaluation of these strategies suggests that faster and more efficient recovery is possible through network centrality measures. Optimal recovery strategies may be different per hazard, per community within a network, and for different measures of partial recovery. In addition, topological characterization provides a means for interpreting the comparative performance of proposed recovery strategies. The methods can be directly extended to other Large-Scale Critical Lifeline Infrastructure Networks including transportation, water, energy and communications systems that are threatened by natural or human-induced hazards, including cascading failures. Furthermore, the quantitative framework developed here can generalize across natural, engineered and human systems, offering an actionable and generalizable approach for emergency management in particular as well as for network resilience in general.

  15. Simplified containment event tree analysis for the Sequoyah Ice Condenser containment

    Energy Technology Data Exchange (ETDEWEB)

    Galyean, W.J.; Schroeder, J.A.; Pafford, D.J. (EG and G Idaho, Inc., Idaho Falls, ID (USA))

    1990-12-01

    An evaluation of a Pressurized Water Reactor (PWR) ice condenser containment was performed. In this evaluation, simplified containment event trees (SCETs) were developed that utilized the vast storehouse of information generated by the NRC's Draft NUREG-1150 effort. Specifically, the computer programs and data files produced by the NUREG-1150 analysis of Sequoyah were used to electronically generate SCETs, as opposed to the NUREG-1150 accident progression event trees (APETs). This simplification was performed to allow graphic depiction of the SCETs in typical event tree format, which facilitates their understanding and use. SCETs were developed for five of the seven plant damage state groups (PDSGs) identified by the NUREG-1150 analyses, which includes: both short- and long-term station blackout sequences (SBOs), transients, loss-of-coolant accidents (LOCAs), and anticipated transient without scram (ATWS). Steam generator tube rupture (SGTR) and event-V PDSGs were not analyzed because of their containment bypass nature. After being benchmarked with the APETs, in terms of containment failure mode and risk, the SCETs were used to evaluate a number of potential containment modifications. The modifications were examined for their potential to mitigate or prevent containment failure from hydrogen burns or direct impingement on the containment by the core, (both factors identified as significant contributors to risk in the NUREG-1150 Sequoyah analysis). However, because of the relatively low baseline risk postulated for Sequoyah (i.e., 12 person-rems per reactor year), none of the potential modifications appear to be cost effective. 15 refs., 10 figs. , 17 tabs.

  16. Adolescent Alcohol Exposure Persistently Impacts Adult Neurobiology and Behavior

    Science.gov (United States)

    Vetreno, Ryan P.; Broadwater, Margaret A.; Robinson, Donita L.

    2016-01-01

    Adolescence is a developmental period when physical and cognitive abilities are optimized, when social skills are consolidated, and when sexuality, adolescent behaviors, and frontal cortical functions mature to adult levels. Adolescents also have unique responses to alcohol compared with adults, being less sensitive to ethanol sedative–motor responses that most likely contribute to binge drinking and blackouts. Population studies find that an early age of drinking onset correlates with increased lifetime risks for the development of alcohol dependence, violence, and injuries. Brain synapses, myelination, and neural circuits mature in adolescence to adult levels in parallel with increased reflection on the consequence of actions and reduced impulsivity and thrill seeking. Alcohol binge drinking could alter human development, but variations in genetics, peer groups, family structure, early life experiences, and the emergence of psychopathology in humans confound studies. As adolescence is common to mammalian species, preclinical models of binge drinking provide insight into the direct impact of alcohol on adolescent development. This review relates human findings to basic science studies, particularly the preclinical studies of the Neurobiology of Adolescent Drinking in Adulthood (NADIA) Consortium. These studies focus on persistent adult changes in neurobiology and behavior following adolescent intermittent ethanol (AIE), a model of underage drinking. NADIA studies and others find that AIE results in the following: increases in adult alcohol drinking, disinhibition, and social anxiety; altered adult synapses, cognition, and sleep; reduced adult neurogenesis, cholinergic, and serotonergic neurons; and increased neuroimmune gene expression and epigenetic modifiers of gene expression. Many of these effects are specific to adolescents and not found in parallel adult studies. AIE can cause a persistence of adolescent-like synaptic physiology, behavior, and sensitivity

  17. Variation of Spirulina maxima biomass production in different depths of urea-used culture medium

    Science.gov (United States)

    Affan, Md-Abu; Lee, Dae-Won; Al-Harbi, Salim Marzoog; Kim, Han-Jun; Abdulwassi, Najah Ibrahim; Heo, Soo-Jin; Oh, Chulhong; Park, Heung-Sik; Ma, Chae Woo; Lee, Hyeon-Yong; Kang, Do-Hyung

    2015-01-01

    Fewer studies have assessed the outdoor cultivation of Spirulina maxima compared with S. platensis, although the protein content of S. maxima is higher than S. platensis. Spirulina growth medium requires an increased amount of NaHCO3, Na2CO3, and NaNO3, which increases the production cost. Therefore, the current study used a low-cost but high-efficiency biomass production medium (Medium M-19) after testing 33 different media. The medium depth of 25 cm (group A) was sub-divided into A1 (50% cover with a black curtain (PolyMax, 12 oz ultra-blackout), A2 (25% cover), and A3 (no cover). Similarly the medium depths of 30 and 35 cm were categorized as groups B (B1, B2, and B3) and C (C1, C2, and C3), respectively, and the effects of depth and surface light availability on growth and biomass production were assessed. The highest biomass production was 2.05 g L-1 in group A2, which was significantly higher (p < 0.05) than that in all other groups and sub-groups. Spirulina maxima died in B1 and C1 on the fifth day of culture. The biochemical composition of the biomass obtained from A2 cultures, including protein, carbohydrate, lipid, moisture, and ash, was 56.59%, 14.42%, 0.94%, 5.03%, and 23.02%, respectively. Therefore, S. maxima could be grown outdoors with the highest efficiency in urea-enriched medium at a 25-cm medium depth with 25% surface cover or uncovered. PMID:26691456

  18. Variation of Spirulina maxima biomass production in different depths of urea-used culture medium

    Directory of Open Access Journals (Sweden)

    Md-Abu Affan

    2015-01-01

    Full Text Available Fewer studies have assessed the outdoor cultivation of Spirulina maxima compared with S. platensis, although the protein content of S. maxima is higher than S. platensis. Spirulina growth medium requires an increased amount of NaHCO3, Na2CO3, and NaNO3, which increases the production cost. Therefore, the current study used a low-cost but high-efficiency biomass production medium (Medium M-19 after testing 33 different media. The medium depth of 25 cm (group A was sub-divided into A1 (50% cover with a black curtain (PolyMax, 12 oz ultra-blackout, A2 (25% cover, and A3 (no cover. Similarly the medium depths of 30 and 35 cm were categorized as groups B (B1, B2, and B3 and C (C1, C2, and C3, respectively, and the effects of depth and surface light availability on growth and biomass production were assessed. The highest biomass production was 2.05 g L-1 in group A2, which was significantly higher (p < 0.05 than that in all other groups and sub-groups. Spirulina maxima died in B1 and C1 on the fifth day of culture. The biochemical composition of the biomass obtained from A2 cultures, including protein, carbohydrate, lipid, moisture, and ash, was 56.59%, 14.42%, 0.94%, 5.03%, and 23.02%, respectively. Therefore, S. maxima could be grown outdoors with the highest efficiency in urea-enriched medium at a 25-cm medium depth with 25% surface cover or uncovered.

  19. [Treatment processes of pre-alcoholism and alcohol dependence targeted towards drinking reduction].

    Science.gov (United States)

    Yoshimura, Atsushi; Maesato, Hitoshi; Hisatomi, Nobuko; Higuchi, Susumu

    2013-02-01

    Since the 1990s, we have suggested the concept of pre-alcoholism which encompasses patients who have drunk a great deal of alcohol leading to alcohol related problems such as health issues, domestic violence, drunken driving and black-outs. Pre-alcoholism excludes alcohol-dependent patients who have experienced continuous drinking or withdrawal symptoms. We have treated many outpatients with pre-alcoholism for several years. Our regimen demands that the patients must be abstinent for half a year at the beginning of their treatment. After half a year they can choose whether they will continue to be abstinent or they will resume drinking with the aim of reducing their total alcohol consumption. The study clarified the character of pre-alcoholism by investigation of the patients' background and re-diagnosis of the patients based on the International Classification of Diseases, 10th Revision (ICD-10). A remarkable ratio of pre-alcoholic patients was diagnosed with alcohol dependence under ICD-10. We classified pre-alcoholic patients into two groups, one diagnosed as having ICD-10-classed alcohol dependence and the other which did not fulfill the ICD-10 diagnostic criteria of alcohol dependence, and examined the therapeutic processes of the two groups. It was shown that most pre-alcoholic patients could finally take required courses of treatment by themselves without regard to diagnosis under ICD-10, even if they chose any treatment and made alcohol related mistakes on the way. Our findings suggested that pre-alcoholic patients, a portion of whom may have exhibited mild alcohol dependence, could select drinking reduction as a primary goal of treatment after a certain period of abstinence.

  20. Implementation of passive autocatalytic recombiner system as a hydrogen mitigation system in Korean nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Hyun; Sung, Je Joong; Ha, Sang Jun [Korea Hydro and Nuclear Power Co. Ltd., Central Research Institute, Daejeon (Korea, Republic of); Yeo, In Seon [KEPCO Engineering and Construction Co. Ltd., Gyeonggi-do (Korea, Republic of)

    2015-08-15

    Ensuring the containment integrity during a severe accident in nuclear power reactor by maintaining the hydrogen concentration below an acceptable level has been recognized to be of critical importance since Three Mile Island and Fukushima Daiichi nuclear power plant accidents. Although there exist various mitigation measures for hydrogen risk, a passive autocatalytic recombiner (PAR) has been emphasized as a viable option for the mitigation of hydrogen risk under the extended station blackout conditions due to its passive operation characteristics for the hydrogen removal. To enhance the capability of hydrogen control, the hydrogen mitigation system with various types of PARs has been implemented for all nuclear power plants in Korea. This paper presents an implementation procedure of PAR system and the analysis results to determine the location and capacity of PAR in OPR1000. Various accident scenarios have been adopted considering important event sequences from a combination of probabilistic methods, deterministic methods and sound engineering judgment. A MAAP 4.0.6+ with a multi-compartment model has been used as an analysis tool with conservative hydrogen generation and removal models. The detailed analyses have been performed for selected severe accident scenarios including sensitivity analysis with/without operations of various safety systems. The possibility of global flame acceleration (FA) and deflagration-to-detonation transient (DDT) has been assessed with sigma (flame acceleration potential) and 7-lambda (DDT potential) criterion. It is concluded that the newly designed hydrogen mitigation system with twenty-four (24) PARs can effectively remove hydrogen in the containment atmosphere and prevent global FA and DDT.