WorldWideScience

Sample records for providing reactive power

  1. Reactive power compensator

    Science.gov (United States)

    El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.; Chen, Mingliang; Andexler, George; Huang, Tony

    1992-01-01

    A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation.

  2. Reactive power compensator

    Energy Technology Data Exchange (ETDEWEB)

    El-Sharkawi, Mohamed A. (Renton, WA); Venkata, Subrahmanyam S. (Woodinville, WA); Chen, Mingliang (Kirkland, WA); Andexler, George (Everett, WA); Huang, Tony (Seattle, WA)

    1992-01-01

    A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation.

  3. Reactive power compensating system

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Timothy J. (Redondo Beach, CA); El-Sharkawi, Mohamed A. (Renton, WA); Venkata, Subrahmanyam S. (Seattle, WA)

    1987-01-01

    The reactive power of an induction machine is compensated by providing fixed capacitors on each phase line for the minimum compensation required, sensing the current on one line at the time its voltage crosses zero to determine the actual compensation required for each phase, and selecting switched capacitors on each line to provide the balance of the compensation required.

  4. A Tariff for Reactive Power

    Energy Technology Data Exchange (ETDEWEB)

    Kueck, John D [ORNL; Kirby, Brendan J [ORNL; Li, Fangxing [ORNL; Tufon, Christopher [Pacific Gas and Electric Company; Isemonger, Alan [California Independent System Operator

    2008-07-01

    Two kinds of power are required to operate an electric power system: real power, measured in watts, and reactive power, measured in volt-amperes reactive or VARs. Reactive power supply is one of a class of power system reliability services collectively known as ancillary services, and is essential for the reliable operation of the bulk power system. Reactive power flows when current leads or lags behind voltage. Typically, the current in a distribution system lags behind voltage because of inductive loads such as motors. Reactive power flow wastes energy and capacity and causes voltage droop. To correct lagging power flow, leading reactive power (current leading voltage) is supplied to bring the current into phase with voltage. When the current is in phase with voltage, there is a reduction in system losses, an increase in system capacity, and a rise in voltage. Reactive power can be supplied from either static or dynamic VAR sources. Static sources are typically transmission and distribution equipment, such as capacitors at substations, and their cost has historically been included in the revenue requirement of the transmission operator (TO), and recovered through cost-of-service rates. By contrast, dynamic sources are typically generators capable of producing variable levels of reactive power by automatically controlling the generator to regulate voltage. Transmission system devices such as synchronous condensers can also provide dynamic reactive power. A class of solid state devices (called flexible AC transmission system devices or FACTs) can provide dynamic reactive power. One specific device has the unfortunate name of static VAR compensator (SVC), where 'static' refers to the solid state nature of the device (it does not include rotating equipment) and not to the production of static reactive power. Dynamic sources at the distribution level, while more costly would be very useful in helping to regulate local voltage. Local voltage regulation would

  5. Positioning strategies for decentralized energy resources providing reactive power voltage control; Anlagenauswahl und -positionierung zur Spannungsstuetzung mittels Blindleistungsmanagement dezentraler Erzeugungsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Matrose, Claas; Goedde, Markus; Cramer, Moritz; Potratz, Fabian; Pollok, Thomas; Schnettler, Armin [RWTH Aachen Univ. (Germany). Inst. fuer Hochspannungstechnik

    2012-07-01

    The integration of decentralized generation into power distribution grids in Germany has reached a level at which more and more grid reinforcement is required in order to keep voltages within the given limits. The consumption of reactive power by decentralized generation systems can reduce the voltage rise, which is caused by active power in-feed of such systems. Caused by different characteristics of overhead lines and cables, this effect significantly varies. Parameter studies of four commonly used types of lines, of different power ratings of decentralized generation systems as well as different lengths of lines can quantify the effects. It can be shown that - depending on the characteristics of a specific grid - the grid capacity for power in-feed can be increased by factors between 1.5 and 10. (orig.)

  6. Substation Reactive Power Regulation Strategy

    Science.gov (United States)

    Zhang, Junfeng; Zhang, Chunwang; Ma, Daqing

    2018-01-01

    With the increasing requirements on the power supply quality and reliability of distribution network, voltage and reactive power regulation of substations has become one of the indispensable ways to ensure voltage quality and reactive power balance and to improve the economy and reliability of distribution network. Therefore, it is a general concern of the current power workers and operators that what kind of flexible and effective control method should be used to adjust the on-load tap-changer (OLTC) transformer and shunt compensation capacitor in a substation to achieve reactive power balance in situ, improve voltage pass rate, increase power factor and reduce active power loss. In this paper, based on the traditional nine-zone diagram and combining with the characteristics of substation, a fuzzy variable-center nine-zone diagram control method is proposed and used to make a comprehensive regulation of substation voltage and reactive power. Through the calculation and simulation of the example, this method is proved to have satisfactorily reconciled the contradiction between reactive power and voltage in real-time control and achieved the basic goal of real-time control of the substation, providing a reference value to the practical application of the substation real-time control method.

  7. Reactive Power Compensating System.

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Timothy J.; El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.

    1985-01-04

    The circuit was designed for the specific application of wind-driven induction generators. It has great potential for application in any situation where a varying reactive power load is present, such as with induction motors or generators, or for transmission network compensation.

  8. Reactive Power from Distributed Energy

    Energy Technology Data Exchange (ETDEWEB)

    Kueck, John; Kirby, Brendan; Rizy, Tom; Li, Fangxing; Fall, Ndeye

    2006-12-15

    Distributed energy is an attractive option for solving reactive power and distribution system voltage problems because of its proximity to load. But the cost of retrofitting DE devices to absorb or produce reactive power needs to be reduced. There also needs to be a market mechanism in place for ISOs, RTOs, and transmission operators to procure reactive power from the customer side of the meter where DE usually resides. (author)

  9. Reactive Power from Distributed Energy

    International Nuclear Information System (INIS)

    Kueck, John; Kirby, Brendan; Rizy, Tom; Li, Fangxing; Fall, Ndeye

    2006-01-01

    Distributed energy is an attractive option for solving reactive power and distribution system voltage problems because of its proximity to load. But the cost of retrofitting DE devices to absorb or produce reactive power needs to be reduced. There also needs to be a market mechanism in place for ISOs, RTOs, and transmission operators to procure reactive power from the customer side of the meter where DE usually resides. (author)

  10. Water reactive hydrogen fuel cell power system

    Science.gov (United States)

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

    2014-01-21

    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into a fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  11. Reactive Power Management in Electric Power Systems

    African Journals Online (AJOL)

    (Ferranti effect) would limit the power transfer and the transmission range in the absence of any compensation measures. Journal of EAEA, Vol 14, 1997. In this paper, the management of the reactive power is explored with the aim of improving the quality and the reliability of the supply in the EELPA's interconnected system ...

  12. Reactive power supply by distributed generators

    OpenAIRE

    Braun, M.

    2008-01-01

    Distributed reactive power supply is necessary in distribution networks for an optimized network operation. This paper presents first the reactive power supply capabilities of generators connected to the distribution network (distributed generators). In a second step an approach is proposed of determining the energy losses resulting from reactive power supply by distributed generators. The costs for compensating these losses represent the operational costs of reactive power supply. These cost...

  13. An introduction to reactive power compensation for wind farms

    International Nuclear Information System (INIS)

    Nigim, K.A.; Cairo Univ., Giza; Zobaa, A.F.; El Amin, I.

    2005-01-01

    The paper summarises the refereed contributions of seven articles reviewed for publication in the IJETP - Special Issue on 'Reactive compensation for wind farms'. The main goal of the special issue is to provide a forum to exchange information on the reactive power compensation requirements for wind farms and introducing possible price mechanisms for today's deregulated power industry. Uncompensated reactive power causes stress on the hosting utility grid as well as added expenses, which create in difficulties for power purchasing agreements from independent wind energy producers. Wind power producers need to comply with the hosting utility grid interconnection standards, e.g., voltage and frequency, as well as to provide controllable active and reactive sources of power. Active power supply is mainly dependent on the potential of wind power produced and the turbine design. Reactive power demand on the other hand depends on the conversion devices and the recovered power quantity fed to the grid. Static Var Compensators (SVC), Unified Power Quality Conditioners (UPQC), Unified Power Flow Controllers (UPFC), and the Distributed Static Synchronous Compensators (DSTATCOM) are all new emerging devices aimed at regulating the reactive power requirements. The excellent controllability of these devices has paved the way to flexible and dynamic controllers that are capable of regulating the flow of active and reactive power components. These devices are now suggested for the control of the reactive power requirement of wind generators. Studies have demonstrated acceptable voltage stabilisation results. This has increased the penetration level of wind power into existing distribution networks in many countries. (Author)

  14. Reactive power compensation a practical guide

    CERN Document Server

    Hofmann, Wolfgang; Just, Wolfgang

    2012-01-01

    The comprehensive resource on reactive power compensation, presenting the design, application and operation of reactive power equipment and installations The area of reactive power compensation is gaining increasing importance worldwide. If suitably designed, it is capable of improving voltage quality significantly, meaning that losses in equipment and power systems are reduced, the permissible loading of equipment can be increased, and the over-all stability of system operation improved. Ultimately, energy use and CO2 emisson are reduced. This unique guide discusses the

  15. Reactive power management and voltage control in deregulated power markets

    Science.gov (United States)

    Spangler, Robert G.

    The research that is the subject of this dissertation is about the management of reactive power and voltage support in the wholesale open access power markets in the United States (US). The purpose of this research is to place decisions about open access market structures, as they relate to reactive power and voltage control, on a logical and consistent economic basis, given the engineering needs of a commercial electric power system. An examination of the electricity markets operating in the US today reveals that current approaches to reactive power management and voltage support are extensions of those based on historical, regulated monopoly electric service. A case for change is built by first looking at the subject of reactive power from an engineering viewpoint and then from an economic perspective. Ultimately, a set of market rules for managing reactive power and voltage support is proposed. The proposal suggests that cost recovery for static and dynamic VARs is appropriately accomplished through the regulated transmission cost of service. Static VAR cost recovery should follow traditional rate recovery methodologies. In the case of dynamic VARs, this work provides a methodology based on the microeconomic theory of the firm for determining such cost. It further suggests that an operational strategy that reduces and limits the use of dynamic VARs, during normal operations, is appropriate. This latter point leads to an increase in the fixed cost of the transmission network but prevents price spikes and short supply situations from affecting, or being affected by, the reactive capability limitations associated with dynamic VARs supplied from synchronous generators. The rules are consistent with a market structure that includes competitive generation and their application will result in the communication of a clear understanding of the responsibilities, related to voltage control, of each type of market entity. In this sense, their application will contribute to

  16. An introduction to reactive power compensation for wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Nigim, K.A. [Waterloo Univ., Ont. (Canada). Dept. of Electrical and Computer Engineering; Cairo Univ., Giza (Egypt). Faculty of Engineering; Zobaa, A.F.; El Amin, I. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Electrical Engineering

    2005-07-01

    The paper summarises the refereed contributions of seven articles reviewed for publication in the IJETP - Special Issue on 'Reactive compensation for wind farms'. The main goal of the special issue is to provide a forum to exchange information on the reactive power compensation requirements for wind farms and introducing possible price mechanisms for today's deregulated power industry. Uncompensated reactive power causes stress on the hosting utility grid as well as added expenses, which create in difficulties for power purchasing agreements from independent wind energy producers. Wind power producers need to comply with the hosting utility grid interconnection standards, e.g., voltage and frequency, as well as to provide controllable active and reactive sources of power. Active power supply is mainly dependent on the potential of wind power produced and the turbine design. Reactive power demand on the other hand depends on the conversion devices and the recovered power quantity fed to the grid. Static Var Compensators (SVC), Unified Power Quality Conditioners (UPQC), Unified Power Flow Controllers (UPFC), and the Distributed Static Synchronous Compensators (DSTATCOM) are all new emerging devices aimed at regulating the reactive power requirements. The excellent controllability of these devices has paved the way to flexible and dynamic controllers that are capable of regulating the flow of active and reactive power components. These devices are now suggested for the control of the reactive power requirement of wind generators. Studies have demonstrated acceptable voltage stabilisation results. This has increased the penetration level of wind power into existing distribution networks in many countries. (Author)

  17. On Variable Reverse Power Flow-Part I: Active-Reactive Optimal Power Flow with Reactive Power of Wind Stations

    Directory of Open Access Journals (Sweden)

    Aouss Gabash

    2016-02-01

    Full Text Available It has recently been shown that using battery storage systems (BSSs to provide reactive power provision in a medium-voltage (MV active distribution network (ADN with embedded wind stations (WSs can lead to a huge amount of reverse power to an upstream transmission network (TN. However, unity power factors (PFs of WSs were assumed in those studies to analyze the potential of BSSs. Therefore, in this paper (Part-I, we aim to further explore the pure reactive power potential of WSs (i.e., without BSSs by investigating the issue of variable reverse power flow under different limits on PFs in an electricity market model. The main contributions of this work are summarized as follows: (1 Introducing the reactive power capability of WSs in the optimization model of the active-reactive optimal power flow (A-R-OPF and highlighting the benefits/impacts under different limits on PFs. (2 Investigating the impacts of different agreements for variable reverse power flow on the operation of an ADN under different demand scenarios. (3 Derivation of the function of reactive energy losses in the grid with an equivalent-π circuit and comparing its value with active energy losses. (4 Balancing the energy curtailment of wind generation, active-reactive energy losses in the grid and active-reactive energy import-export by a meter-based method. In Part-II, the potential of the developed model is studied through analyzing an electricity market model and a 41-bus network with different locations of WSs.

  18. Power beaming providing a space power infrastructure

    International Nuclear Information System (INIS)

    Bamberger, J.A.; Coomes, E.P.

    1992-01-01

    This paper, based on two levels of technology maturity, applied the power beaming concept to four panned satellite constellations. The analysis shows that with currently available technology, power beaming can provide mass savings to constellations in orbits ranging from low-Earth orbit to geosynchronous orbit. Two constellations, space surveillance and tracking system and space-based radar, can be supported with current technology. The other two constellations, space-based laser array and boost surveillance and tracking system, will require power and transmission system improvements before their breakeven specific mass is achieved. A doubling of SP-100 conversion efficiency from 10 to 20% would meet or exceed breakeven for these constellations

  19. Multiobjective clearing of reactive power market in deregulated power systems

    International Nuclear Information System (INIS)

    Rabiee, A.; Shayanfar, H.; Amjady, N.

    2009-01-01

    This paper presents a day-ahead reactive power market which is cleared in the form of multiobjective context. Total payment function (TPF) of generators, representing the payment paid to the generators for their reactive power compensation, is considered as the main objective function of reactive power market. Besides that, voltage security margin, overload index, and also voltage drop index are the other objective functions of the optimal power flow (OPF) problem to clear the reactive power market. A Multiobjective Mathematical Programming (MMP) formulation is implemented to solve the problem of reactive power market clearing using a fuzzy approach to choose the best compromise solution according to the specific preference among various non-dominated (pareto optimal) solutions. The effectiveness of the proposed method is examined based on the IEEE 24-bus reliability test system (IEEE 24-bus RTS). (author)

  20. The Large Customer Reactive Power Control Possibilities

    Directory of Open Access Journals (Sweden)

    Robert Małkowski

    2014-03-01

    Full Text Available In this paper the authors wish to draw attention to the rationale for, and the possibility of, the use of local reactive power sources by the Transmission Node Master Controller (TNMC. Large Customers (LC are one of the possible reactive power sources. The paper presents the issues related to the need for coordination between the control systems installed in the LC network, and coordination between control systems of the LC as well as master control systems in the network.

  1. Modelling of power-reactivity coefficient measurement

    International Nuclear Information System (INIS)

    Strmensky, C.; Petenyi, V.; Jagrik, J.; Minarcin, M.; Hascik, R.; Toth, L.

    2005-01-01

    Report describes results of modeling of power-reactivity coefficient analysis on power-level. In paper we calculate values of discrepancies arisen during transient process. These discrepancies can be arisen as result of experiment evaluation and can be caused by disregard of 3D effects on neutron distribution. The results are critically discussed (Authors)

  2. APPLICATION OF MODIFIED POWER FLOW TRACING METHOD FOR REACTIVE POWER PRICING IN PRACTICAL UTILITY SYSTEM

    Directory of Open Access Journals (Sweden)

    M. SUSITHRA

    2017-01-01

    Full Text Available Competitive trend towards restructuring and unbundling of transmission services has resulted in the need to discover the impact of a particular generator to load. This paper initially presents the analysis of three different reactive power valuation methods namely, Modified Ybus , Virtual flow approach and modified power flow tracing to compute the reactive power output from a particular generator to particular load. Among these methods, the modified power flow electricity tracing method is identified as the best method to trace the reactive power contribution from various reactive power sources to loads, transmission line, etc. Also this proposed method breakdown the total reactive power loss in a transmission line into components to be allocated to individual loads. Secondly, based on this Method a novel allocation method for reactive power service for practical system is proposed. Hence, this method can be useful in providing additional insight into power system operation and can be used to modify existing tariffs of charging for reactive power transmission loss and reactive power transmission services. Simulation and comparison results are shown by taking WSCC 9 and IEEE 30 bus system as test system.

  3. Reactive power management of power networks with wind generation

    CERN Document Server

    Amaris, Hortensia; Ortega, Carlos Alvarez

    2012-01-01

    As the energy sector shifts and changes to focus on renewable technologies, the optimization of wind power becomes a key practical issue. Reactive Power Management of Power Networks with Wind Generation brings into focus the development and application of advanced optimization techniques to the study, characterization, and assessment of voltage stability in power systems. Recent advances on reactive power management are reviewed with particular emphasis on the analysis and control of wind energy conversion systems and FACTS devices. Following an introduction, distinct chapters cover the 5 key

  4. Joint excitation and reactive power control in thermal power plant

    Directory of Open Access Journals (Sweden)

    Dragosavac Jasna

    2013-01-01

    Full Text Available The coordinated voltage and reactive power controller, designed for the thermal power plant, is presented in the paper. A brief explanation of the need for such device is given and justification for commissioning of such equipment is outlined. After short description of the theoretical background of the proposed control design, the achieved features of the commissioned equipment are fully given. Achieved performances are illustrated by recorded reactive power and bus voltage responses after commissioning of the described equipment into the largest thermal power plant in Serbia. As it can be seen in presented records, all design targets are met.

  5. Multiagent voltage and reactive power control system

    Directory of Open Access Journals (Sweden)

    I. Arkhipov

    2014-12-01

    Full Text Available This paper is devoted to the research of multiagent voltage and reactive power control system development. The prototype of the system has been developed by R&D Center at FGC UES (Russia. The control system architecture is based on the innovative multiagent system theory application that leads to the achievement of several significant advantages (in comparison to traditional control systems implementation such as control system efficiency enhancement, control system survivability and cyber security.

  6. Adaptive Reactive Power Control of PV Power Plants for Improved Power Transfer Capability under Ultra-Weak Grid Conditions

    DEFF Research Database (Denmark)

    Yang, Dongsheng; Wang, Xiongfei; Liu, Fangcheng

    2018-01-01

    with the unity power factor. Then, considering the reactive power compensation from PV inverters, the minimum SCR in respect to Power Factor (PF) is derived, and the optimized coordination of the active and reactive power is exploited. It is revealed that the power transfer capability of PV power plant under...... of a 200 MW PV power plant demonstrate that the proposed method can ensure the rated power transfer of PV power plant with the SCR of 1.25, provided that the PV inverters are operated with the minimal PF=0.9.......This paper analyzes the power transfer limitation of the PV power plant under the ultra-weak grid condition, i.e., when the Short-Circuit Ratio (SCR) is close to 1. It explicitly identifies that a minimum SCR of 2 is required for the PV power plant to deliver the rated active power when operating...

  7. Design of reactive power procurement in deregulated electricity market

    African Journals Online (AJOL)

    Reactive power management is different in the deregulated electricity market of various countries. In this paper, a novel reactive power procurement model is proposed, which ensure secure and reliable operation of deregulated electricity market. Various issues of reactive power management in the deregulated electricity ...

  8. Index-based reactive power compensation scheme for voltage regulation

    Science.gov (United States)

    Dike, Damian Obioma

    2008-10-01

    Increasing demand for electrical power arising from deregulation and the restrictions posed to the construction of new transmission lines by environment, socioeconomic, and political issues had led to higher grid loading. Consequently, voltage instability has become a major concern, and reactive power support is vital to enhance transmission grid performance. Improved reactive power support to distressed grid is possible through the application of relatively unfamiliar emerging technologies of "Flexible AC Transmission Systems (FACTS)" devices and "Distributed Energy Resources (DERS)." In addition to these infrastructure issues, a lack of situational awareness by system operators can cause major power outages as evidenced by the August 14, 2003 widespread North American blackout. This and many other recent major outages have highlighted the inadequacies of existing power system indexes. In this work, a novel "Index-based reactive compensation scheme" appropriate for both on-line and off-line computation of grid status has been developed. A new voltage stability index (Ls-index) suitable for long transmission lines was developed, simulated, and compared to the existing two-machine modeled L-index. This showed the effect of long distance power wheeling amongst regional transmission organizations. The dissertation further provided models for index modulated voltage source converters (VSC) and index-based load flow analysis of both FACTS and microgrid interconnected power systems using the Newton-Raphson's load flow model incorporated with multi-FACTS devices. The developed package has been made user-friendly through the embodiment of interactive graphical user interface and implemented on the IEEE 14, 30, and 300 bus systems. The results showed reactive compensation has system wide-effect, provided readily accessible system status indicators, ensured seamless DERs interconnection through new islanding modes and enhanced VSC utilization. These outcomes may contribute

  9. Pay-as-bid based reactive power market

    International Nuclear Information System (INIS)

    Amjady, N.; Rabiee, A.; Shayanfar, H.A.

    2010-01-01

    In energy market clearing, the offers are stacked in increasing order and the offer that intersects demand curve, determines the market clearing price (MCP). In reactive power market, the location of reactive power compensator is so important. A low cost reactive producer may not essentially be favorable if it is far from the consumer. Likewise, a high cost local reactive compensator at a heavily loaded demand center of network could be inevitably an alternative required to produce reactive power to maintain the integrity of power system. Given the background, this paper presents a day-ahead reactive power market based on pay-as-bid (PAB) mechanism. Generators expected payment function (EPF) is used to construct a bidding framework. Then, total payment function (TPF) of generators is used as the objective function of optimal power flow (OPF) problem to clear the PAB based market. The CIGRE-32 bus test system is used to examine the effectiveness of the proposed reactive power market.

  10. Pay-as-bid based reactive power market

    Energy Technology Data Exchange (ETDEWEB)

    Amjady, N. [Department of Electrical Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Rabiee, A., E-mail: Rabiee@iust.ac.i [Center of Excellence for Power System Automation and Operation, Department of Electrical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Shayanfar, H.A. [Center of Excellence for Power System Automation and Operation, Department of Electrical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

    2010-02-15

    In energy market clearing, the offers are stacked in increasing order and the offer that intersects demand curve, determines the market clearing price (MCP). In reactive power market, the location of reactive power compensator is so important. A low cost reactive producer may not essentially be favorable if it is far from the consumer. Likewise, a high cost local reactive compensator at a heavily loaded demand center of network could be inevitably an alternative required to produce reactive power to maintain the integrity of power system. Given the background, this paper presents a day-ahead reactive power market based on pay-as-bid (PAB) mechanism. Generators expected payment function (EPF) is used to construct a bidding framework. Then, total payment function (TPF) of generators is used as the objective function of optimal power flow (OPF) problem to clear the PAB based market. The CIGRE-32 bus test system is used to examine the effectiveness of the proposed reactive power market.

  11. Identification of fast power reactivity effect in nuclear power reactor

    International Nuclear Information System (INIS)

    Efanov, A.I.; Kaminskas, V.A.; Lavrukhin, V.S.; Rimidis, A.P.; Yanitskene, D.Yu.

    1987-01-01

    A nuclear power reactor is an object of control with distributed parameters, characteristics of which vary during operation time. At the same time the reactor as the object of control has internal feedback circuits, which are formed as a result of the effects of fuel parameters and a coolant (pressure, temperature, steam content) on the reactor breeding properties. The problem of internal feedback circuit identification in a nuclear power reactor is considered. Conditions for a point reactor identification are obtained and algorithms of parametric identification are constructed. Examples of identification of fast power reactivity effect for the RBMK-1000 reactor are given. Results of experimental testing have shown that the developed method of fast power reactivity effect identification permits according to the data of normal operation to construct adaptive models for the point nuclear reactor, designed for its behaviour prediction in stationary and transition operational conditions. Therefore, the models considered can be used for creating control systems of nuclear power reactor thermal capacity (of RBMK type reactor, in particular) which can be adapted to the change in the internal feedback circuit characteristics

  12. Design of reactive power procurement in deregulated electricity market

    African Journals Online (AJOL)

    user

    novel reactive power procurement model is proposed, which ensure secure and ..... The simulation is performed in the Matlab. .... focus of this paper is a reactive procurement market model, which is a basically two-step optimization process.

  13. Power and power-to-flow reactivity transfer functions in EBR-II [Experimental Breeder Reactor II] fuel

    International Nuclear Information System (INIS)

    Grimm, K.N.; Meneghetti, D.

    1989-01-01

    Reactivity transfer functions are important in determining the reactivity history during a power transient. Overall nodal transfer functions have been calculated for different subassembly types in the Experimental Breeder Reactor II (EBR-II). Steady-state calculations for temperature changes and, hence, reactivities for power changes have been separated into power and power-to-flow-dependent terms. Axial nodal transfer functions separated into power and power-to-flow-dependent components are reported in this paper for a typical EBR-II fuel pin. This provides an improved understanding of the time dependence of these components in transient situations

  14. An Enhanced Islanding Microgrid Reactive Power, Imbalance Power, and Harmonic Power Sharing Scheme

    DEFF Research Database (Denmark)

    He, Jinwei; Lin, Yun Wei; Blaabjerg, Frede

    2015-01-01

    To address inaccurate power sharing problems in autonomous islanding microgrids, an enhanced droop control method through online virtual impedance adjustment is proposed. First, a term associated with DG reactive power, imbalance power, or harmonic power is added to the conventional real power...

  15. An accurate autonomous islanding microgrid reactive power, imbalance power and harmonic power sharing scheme

    DEFF Research Database (Denmark)

    He, Jinwei; Li, Yun Wei; Blaabjerg, Frede

    2013-01-01

    To address inaccurate power sharing problems in autonomous islanding microgrids, an enhanced droop control method through adaptive virtual impedance adjustment is proposed. First, a term associated with DG reactive power, imbalance power or harmonic power is added to the conventional real power...

  16. Secure provision of reactive power ancillary services in competitive electricity markets

    Science.gov (United States)

    El-Samahy, Ismael

    The research work presented in this thesis discusses various complex issues associated with reactive power management and pricing in the context of new operating paradigms in deregulated power systems, proposing appropriate policy solutions. An integrated two-level framework for reactive power management is set forth, which is both suitable for a competitive market and ensures a secure and reliable operation of the associated power system. The framework is generic in nature and can be adopted for any electricity market structure. The proposed hierarchical reactive power market structure comprises two stages: procurement of reactive power resources on a seasonal basis, and real-time reactive power dispatch. The main objective of the proposed framework is to provide appropriate reactive power support from service providers at least cost, while ensuring a secure operation of the power system. The proposed procurement procedure is based on a two-step optimization model. First, the marginal benefits of reactive power supply from each provider, with respect to system security, are obtained by solving a loadability-maximization problem subject to transmission security constraints imposed by voltage and thermal limits. Second, the selected set of generators is determined by solving an optimal power flow (OPF)-based auction. This auction maximizes a societal advantage function comprising generators' offers and their corresponding marginal benefits with respect to system security, and considering all transmission system constraints. The proposed procedure yields the selected set of generators and zonal price components, which would form the basis for seasonal contracts between the system operator and the selected reactive power service providers. The main objective of the proposed reactive power dispatch model is to minimize the total payment burden on the Independent System Operator (ISO), which is associated with reactive power dispatch. The real power generation is

  17. Guidelines for Distribution System Operators on Reactive Power Provision by Electric Vehicles in Low Voltage Grids

    DEFF Research Database (Denmark)

    Zecchino, Antonio; Marinelli, Mattia; Træholt, Chresten

    2017-01-01

    The increasing success of electric vehicles is bringing new technical challenges to power system operators. This work intends to provide guidelines for distribution system operators in terms of reactive power requirements when evaluating and authorizing electric vehicles supply equipment with fast...... the amount of reactive power that an individual electric vehicle is expected to provide when connected to a low voltage feeder, in order to benefit of the desired voltage rise effect in comparison to the case of unitary power factor....

  18. Ancillary reactive power service allocation cost in deregulated markets: a methodology

    International Nuclear Information System (INIS)

    Hernandez, J. Horacio Tovar; Jimenez-Guzman, Miguel; Gutierrez-Alcaraz, Guillermo

    2005-01-01

    This paper presents a methodology to allocate reactive power costs in deregulated markets. Reactive power supply service is decomposed into voltage regulation and reactive power spinning reserve. The proposed methodology is based on sensitivities and the postage-stamp method in order to allocate the total costs service among all participants. With the purpose of achieving this goal, the system operator identifies voltage support and/or reactive power requirements, and looks out for suitable providers. One case study is presented here to illustrate the methodology over a simplified southeastern Mexican grid. (Author)

  19. REACTIVE POWER DEVICES IN SYSTEMS OF ELECTRIC TRACTION

    Directory of Open Access Journals (Sweden)

    M. O. Kostin

    2010-04-01

    Full Text Available A comparative characteristic of different concepts and expressions for determination of reactive power in the circuits with non-sinusoidal electric values has been given. For the first Ukrainian electric locomotives of DE1 type with the system of DC electric traction, the values of reactive power after Budeany, Fryze, and also the differential, integral and generalized reactive powers have been determined. Some measures on reducing its consumption by the DC electric rolling stock have been suggested.

  20. Advanced Reactive Power Reserve Management Scheme to Enhance LVRT Capability

    Directory of Open Access Journals (Sweden)

    Hwanik Lee

    2017-10-01

    Full Text Available Abstract: To increase the utilization of wind power in the power system, grid integration standards have been proposed for the stable integration of large-scale wind power plants. In particular, fault-ride-through capability, especially Low-Voltage-Ride-Through (LVRT, has been emphasized, as it is related to tripping in wind farms. Therefore, this paper proposes the Wind power plant applicable-Effective Reactive power Reserve (Wa-ERPR, which combines both wind power plants and conventional generators at the Point of Interconnection (POI. The reactive power capability of the doubly-fed induction generator wind farm was considered to compute the total Wa-ERPR at the POI with reactive power capability of existing generators. By using the Wa-ERPR management algorithm, in case of a violation of the LVRT standards, the amount of reactive power compensation is computed using the Wa-ERPR management scheme. The proposed scheme calculates the Wa-ERPR and computes the required reactive power, reflecting the change of the system topology pre- and post-contingency, to satisfy the LVRT criterion when LVRT regulation is not satisfied at the POI. The static synchronous compensator (STATCOM with the capacity corresponding to calculated amount of reactive power through the Wa-ERPR management scheme is applied to the POI. Therefore, it is confirmed that the wind power plant satisfies the LVRT criteria by securing the appropriate reactive power at the POI, by applying of the proposed algorithm.

  1. Agent-based reactive power management of power distribution networks with distributed energy generation

    International Nuclear Information System (INIS)

    Rahman, M.S.; Mahmud, M.A.; Oo, A.M.T.; Pota, H.R.; Hossain, M.J.

    2016-01-01

    Highlights: • A coordinated multi-agent system is proposed for reactive power management. • A linear quadratic regulator with a proportional integral controller is designed. • Proposed multi-agent scheme provides accurate estimation and control of the system. • Voltage stability is improved with proper power management for different scenarios. • Results obtained from the proposed scheme is compared to the traditional approach. - Abstract: In this paper, a new agent-based distributed reactive power management scheme is proposed to improve the voltage stability of energy distribution systems with distributed generation units. Three types of agents – distribution system agent, estimator agent, and control agent are developed within the multi-agent framework. The agents simultaneously coordinated their activities through the online information and energy flow. The overall achievement of the proposed scheme depends on the coordination between two tasks – (i) estimation of reactive power using voltage variation formula and (ii) necessary control actions to provide the estimated reactive power to the distribution networks through the distributed static synchronous compensators. A linear quadratic regulator with a proportional integrator is designed for the control agent in order to control the reactive component of the current and the DC voltage of the compensators. The performance of the proposed scheme is tested on a 10-bus power distribution network under various scenarios. The effectiveness is validated by comparing the proposed approach to the conventional proportional integral control approach. It is found that, the agent-based scheme provides excellent robust performance under various operating conditions of the power distribution network.

  2. Dynamic Reactive Power Control in Offshore HVDC Connected Wind Power Plants

    DEFF Research Database (Denmark)

    Sakamuri, Jayachandra N.; Cutululis, Nicolaos Antonio; Rather, Zakir Hussain

    2016-01-01

    This paper presents a coordinated reactive power control for a HVDC connected cluster of offshore wind power plants (WPPs). The reactive power reference for the WPP cluster is estimated by an optimization algorithm aiming at minimum active power losses in the offshore AC Grid. For each optimal......, such as wind turbine (WT) terminal, collector cable, and export cable, on the dynamic voltage profile of the offshore grid is investigated. Furthermore, the dynamic reactive power contribution from WTs from different WPPs of the cluster for such faults has also been studied....... reactive power set point, the OWPP cluster controller generates reactive power references for each WPP which further sends the AC voltage/ reactive power references to the associated WTs based on their available reactive power margin. The impact of faults at different locations in the offshore grid...

  3. Reactive power control with CHP plants - A demonstration

    DEFF Research Database (Denmark)

    Nyeng, Preben; Østergaard, Jacob; Andersen, Claus A.

    2010-01-01

    power rating of 7.3 MW on two synchronous generators. A closed-loop control is implemented, that remote controls the CHP plant to achieve a certain reactive power flow in a near-by substation. The solution communicates with the grid operator’s existing SCADA system to obtain measurements from...... lines to underground cables has changed the reactive power balance, and third, the TSO has introduced restrictions in the allowed exchange of reactive power between the transmission system and distribution grids (known as the Mvar-arrangement). The demonstration includes a CHP plant with an electric......In this project the potential for ancillary services provision by distributed energy resources is investigated. Specifically, the provision of reactive power control by combined heat and power plants is examined, and the application of the new standard for DER communication systems, IEC 61850...

  4. Portable digital reactivity meter for power reactors

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, G [Nuklear-Ingenieur Service G.m.b.H., Hanau (Germany, F.R.)

    1977-07-01

    A digital reactivity meter has been developed, which can be used for all kinds of kinetic reactivity measurements in PWR's and BWR's. The input signals may be supplied by standard neutron detectors of the reactor. The hardware configuration consists of a minicomputer with ADC and DAC, a 'Silent' terminal and a high speed paper tape reader/punch. It is easily transportable. The reactivity meter solves the inverse kinetics equations for 6 delayed neutron groups, simultaneously for up to 8 logarithmic or linear neutron flux signals. It has been successfully tested at Biblis A PWR and the KRB BWR.

  5. Power flattening and reactivity suppression strategies for the Canadian supercritical water reactor concept

    International Nuclear Information System (INIS)

    McDonald, M.; Colton, A.; Pencer, J.

    2015-01-01

    The Canadian supercritical water-cooled reactor (SCWR) is a conceptual heavy water moderated, supercritical light water cooled pressure tube reactor. In contrast to current heavy water power reactors, the Canadian SCWR will be a batch fuelled reactor. Associated with batch fuelling is a large beginning-of-cycle excess reactivity. Furthermore, radial power peaking arising as a consequence of batch refuelling must be mitigated in some way. In this paper, burnable neutron absorber (BNA) added to fuel and absorbing rods inserted into the core are considered for reactivity management and power flattening. A combination of approaches appears adequate to reduce the core radial power peaking, while also providing reactivity suppression. (author)

  6. Formation for the calculation of reactivity without nuclear power history

    International Nuclear Information System (INIS)

    Suescun Diaz, Daniel; Senra Martinez, Aquilino; Carvalho Da Silva, Fernando

    2007-01-01

    This paper presents a new method for the solution of the inverse point kinetics equation. This method is based on the integration by parts of the integral of the inverse point kinetics equation, which results in a power series in terms of the nuclear power in time dependence. With the imposition of conditions to the nuclear power, the reactivity is represented as first and second derivatives of this nuclear power. This new calculation method for reactivity has very special characteristics, amongst which the possibility of using longer sampling period, and the possibility of restarting the calculation, after its interruption, allowing the calculation of reactivity in a non-continuous way. Beside that, the reactivity can be obtained independent of the nuclear power memory. (author)

  7. Reactive power control methods for improved reliability of wind power inverters under wind speed variations

    DEFF Research Database (Denmark)

    Ma, Ke; Liserre, Marco; Blaabjerg, Frede

    2012-01-01

    method to relieve the thermal cycling of power switching devices under severe wind speed variations, by circulating reactive power among the parallel power converters in a WTS or among the WTS's in a wind park. The amount of reactive power is adjusted to limit the junction temperature fluctuation...

  8. Reactive power compensation and loss reduction in large industrial enterprises

    Energy Technology Data Exchange (ETDEWEB)

    Jovanovic, S; Gajic, B; Mijailovic, S [Institute Nikola Tesla, Beograd (Yugoslavia)

    1991-12-01

    This paper considers the reactive power compensation and the active power and energy loss reduction of large radial power networks in the Serbian mine and smelting industry. It gives an efficient optimization procedure for positioning and sizing capacitors in large industrial systems integrated with a simple network analysis method. (Author).

  9. Broadband and High power Reactive Jamming Resilient Wireless Communication

    Science.gov (United States)

    2017-10-21

    Broadband and High -power Reactive Jamming Resilient Wireless Communication The views, opinions and/or findings contained in this report are those of... available in extremely hostile environments, where FHSS and DSSS are completely defeated by a broadband and high -power reactive jammer. b. Wireless...SECURITY CLASSIFICATION OF: 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 13. SUPPLEMENTARY NOTES 12. DISTRIBUTION AVAILIBILITY STATEMENT 6. AUTHORS

  10. EVALUATING DEGREE OF ACTIVE POWER LOSSES REDUCTION IN THE ELECTRIC POWER LINES WITH REACTIVE POWER COMPENSATION

    Directory of Open Access Journals (Sweden)

    V. N. Radkevich

    2016-01-01

    Full Text Available The paper considers evaluation procedure for the degree of active power losses reduction in the power transmission lines under 1 kV and 6–10 kV of the systems of electric power supply of industrial enterprises with compensating installations mounted at the side of the customer. The capacitor installations conform to the applied voltage level and factor in dielectric losses in the capacitors. The voltage at the compensating device terminal changes from 0.95 to 1.05 of the capacitors nominal voltage. The study did not account for reactive power losses in the line, nor did it for its charge capacity, conditioned by relative shortness of the cable lines generally operating in the mains of industrial enterprises. For this reason, the quantities of reactive power being consumed and generated by the transmission line are negligible and do not significantly affect the reactive power flux. The researchers obtain functional relations that allow estimating the degree of power loss reduction in the transmission line factoring in its explicit initial data. They perform mathematical analysis of the obtained functional relations and study the function by means of derivatives. The function extremum points are found as well as the intervals of its increment and decrement. A graphical research of the obtained functional relation is performed. It is ascertained that reduction of the active power losses is contingent on the line and the capacitor-installation engineering factors, the electrical energy consumer reactive load value as well as the voltage applied to the capacitor installation. The functional relations presented in the article can be employed in scoping calculation necessary for decision making on the reactive power compensation in systems of the industrial facilities electric power supply. Their account will allow a more accurate estimate of technical and economic effect of the capacitor bank installation in the electrical mains under 1 kV and 6

  11. A New Framework for Reactive Power Market Considering Power System Security

    Directory of Open Access Journals (Sweden)

    A. Rabiee

    2009-09-01

    Full Text Available This paper presents a new framework for the day-ahead reactive power market based on the uniform auction price. Voltage stability and security have been considered in the proposed framework. Total Payment Function (TPF is suggested as the objective function of the Optimal Power Flow (OPF used to clear the reactive power market. Overload, voltage drop and voltage stability margin (VSM are included in the constraints of the OPF. Another advantage of the proposed method is the exclusion of Lost Opportunity Cost (LOC concerns from the reactive power market. The effectiveness of the proposed reactive power market is studied based on the CIGRÉ-32 bus test system.

  12. Impact of Reactive Power Injection Outside Feed-In Hours on the Reliability of Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Anurag, Anup; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    , the analysis enables the translation from long-term mission profiles to device thermal loading, considering the operation at night. An analytical lifetime model is then used for lifetime quantization based on the Palgrem Miner rule. Thereafter, considering the lifetime reduction of the PV inverter......Current energy paradigm of mixed renewables seems to urgently require reactive power provision at various feed-in points of the utility grid. Photovoltaic (PV) inverters are able to provide reactive power in a decentralized manner at the grid-connection point even outside active power feed......-in operation, especially at night. This serves as a motivation for utilizing the PV inverters at night for reactive power compensation. Thus, a detailed analysis on the impact of reactive power injection by PV inverters outside feed-in operation on the thermal performance and also the reliability is performed...

  13. A DFIG Islanding Detection Scheme Based on Reactive Power Infusion

    Science.gov (United States)

    Wang, M.; Liu, C.; He, G. Q.; Li, G. H.; Feng, K. H.; Sun, W. W.

    2017-07-01

    A lot of research has been done on photovoltaic (the “PV”) power system islanding detection in recent years. As a comparison, much less attention has been paid to islanding in wind turbines. Meanwhile, wind turbines can work in islanding conditions for quite a long period, which can be harmful to equipments and cause safety hazards. This paper presents and examines a double fed introduction generation (the “DFIG”) islanding detection scheme based on feedback of reactive power and frequency and uses a trigger signal of reactive power infusion which can be obtained by dividing the voltage total harmonic distortion (the "THD") by the voltage THD of last cycle to avoid the deterioration of power quality. This DFIG islanding detection scheme uses feedback of reactive power current loop to amplify the frequency differences in islanding and normal conditions. Simulation results show that the DFIG islanding detection scheme is effective.

  14. Optimized Reactive Power Flow of DFIG Power Converters for Better Reliability Performance Considering Grid Codes

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Lau, Mogens

    2015-01-01

    . In order to fulfill the modern grid codes, over-excited reactive power injection will further reduce the lifetime of the rotor-side converter. In this paper, the additional stress of the power semiconductor due to the reactive power injection is firstly evaluated in terms of modulation index...

  15. Compensation of Reactive Power from Wind Turbines with Power Electronics Equipment

    DEFF Research Database (Denmark)

    Pedersen, Jørgen Kaas

    1996-01-01

    Wind turbines with induction generators consume reactive power. Apart from the no load consumption, which is nearing constant and is being compensated for using capacitors, the consumption of reactive power varies almost proportional with the power production, which can vary immensely. Except tha...

  16. Coordination of baseload power plant group control with static reactive power compensator control

    Directory of Open Access Journals (Sweden)

    Zbigniew Szczerba

    2012-06-01

    Full Text Available Reactive power sources in power system nodes: generators and static reactive power compensators, are controlled by control systems. Generators – by generator node group controllers, compensators – by voltage controllers. The paper presents issues of these control systems’ coordination and proposals for its implementation.

  17. Voltage Sag Mitigation and Load Reactive Power Compensation by UPQC

    OpenAIRE

    Ajitha, P; Jananisri, D

    2014-01-01

    This paper presents Unified Power Quality Conditioner(UPQC) that consist of series inverter and shunt inverter in back to back configuration which simultaneously compensate the power quality(PQ) problems of both voltage sag and load reactive power compensation . In this paper ,Neural network is tool which is considered for solving power quality problems. The simulation results from MATLAB/SIMULINK are discussed to validate the proposed method.

  18. A new computational method for reactive power market clearing

    International Nuclear Information System (INIS)

    Zhang, T.; Elkasrawy, A.; Venkatesh, B.

    2009-01-01

    After deregulation of electricity markets, ancillary services such as reactive power supply are priced separately. However, unlike real power supply, procedures for costing and pricing reactive power supply are still evolving and spot markets for reactive power do not exist as of now. Further, traditional formulations proposed for clearing reactive power markets use a non-linear mixed integer programming formulation that are difficult to solve. This paper proposes a new reactive power supply market clearing scheme. Novelty of this formulation lies in the pricing scheme that rewards transformers for tap shifting while participating in this market. The proposed model is a non-linear mixed integer challenge. A significant portion of the manuscript is devoted towards the development of a new successive mixed integer linear programming (MILP) technique to solve this formulation. The successive MILP method is computationally robust and fast. The IEEE 6-bus and 300-bus systems are used to test the proposed method. These tests serve to demonstrate computational speed and rigor of the proposed method. (author)

  19. Simplified reactive power management strategy for complex power grids under stochastic operation and incomplete information

    DEFF Research Database (Denmark)

    Vlachogiannis, Ioannis (John)

    2009-01-01

    grids is a major issue for system operators. Under these circumstances an online reactive power management strategy with minimum risk concerning all uncertain and stochastic parameters is proposed. Therefore, new concepts such as reactive power-weighted node-to-node linking and reactive power control......In the current released energy market, the large-scale complex transmission networks and the distribution ones with dispersed energy sources and "intelligent" components operate under uncertainties, stochastic and prior incomplete information. A safe and reliable operation of such complex power...... capability are introduced. A distributed and interconnected stochastic learning automata system is implemented to manage, in a unified and unique way, the reactive power in complex power grids with stochastic reactive power demand and detect the vulnerable part. The proposed simplified strategy can also...

  20. Reactive power planning with FACTS devices using gravitational search algorithm

    Directory of Open Access Journals (Sweden)

    Biplab Bhattacharyya

    2015-09-01

    Full Text Available In this paper, Gravitational Search Algorithm (GSA is used as optimization method in reactive power planning using FACTS (Flexible AC transmission system devices. The planning problem is formulated as a single objective optimization problem where the real power loss and bus voltage deviations are minimized under different loading conditions. GSA based optimization algorithm and particle swarm optimization techniques (PSO are applied on IEEE 30 bus system. Results show that GSA can also be a very effective tool for reactive power planning.

  1. Ant colony search algorithm for optimal reactive power optimization

    Directory of Open Access Journals (Sweden)

    Lenin K.

    2006-01-01

    Full Text Available The paper presents an (ACSA Ant colony search Algorithm for Optimal Reactive Power Optimization and voltage control of power systems. ACSA is a new co-operative agents’ approach, which is inspired by the observation of the behavior of real ant colonies on the topic of ant trial formation and foraging methods. Hence, in the ACSA a set of co-operative agents called "Ants" co-operates to find good solution for Reactive Power Optimization problem. The ACSA is applied for optimal reactive power optimization is evaluated on standard IEEE, 30, 57, 191 (practical test bus system. The proposed approach is tested and compared to genetic algorithm (GA, Adaptive Genetic Algorithm (AGA.

  2. Calculation of research reactor RA power at uncontrolled reactivity changes

    International Nuclear Information System (INIS)

    Cupac, S.

    1978-01-01

    The safety analysis of research reactor RA involves also the calculation of reactor power at uncontrolled reactivity changes. The corresponding computer code, based on Point Kinetics Model has been made. The short review of method applied for solving kinetic equations is given and several examples illustrating the reactor behaviour at various reactivity changes are presented. The results already obtained are giving rather rough picture of reactor behaviour in considered situations. This is the consequence of using simplified feed back and reactor cooling models, as well as temperature reactivity coefficients, which do not correspond to the actual reactor RA structure (which is now only partly fulfilled with 80% enriched uranium fuel). (author) [sr

  3. Waste gas could provide power for ships

    Energy Technology Data Exchange (ETDEWEB)

    1970-07-18

    Dual-fuel engines are not new, but a version has been produced which, when used on ships carrying liquefied natural gas (LNG) could operate almost completely on waste gas. In its gas-operating mode, an engine can use the waste gas boiled off an LNG cargo. This wastage, normally allowed to escape to atmosphere, is about 0.25% of the cargo per day. Calculations have shown that this is enough to provide almost all the propulsion needs of a tanker under full cargo. This design is important in that it is suitable for the larger vessels now being required to carry LNG from N. Africa to North America, a journey where the costs of fuel are very considerable. Tests on the engine have indicated that power output is reduced to something like 80% of power under diesel fuel. However, additional advantages, such as cleaner engines with reduced maintenance costs, will help to tip the economic balance even further in favor of the dual purpose unit. This system also is applicable to stationary generating plant, again particularly on LNG tankage units where the same degree of gas boil-off applies.

  4. A stochastic framework for clearing of reactive power market

    International Nuclear Information System (INIS)

    Amjady, N.; Rabiee, A.; Shayanfar, H.A.

    2010-01-01

    This paper presents a new stochastic framework for clearing of day-ahead reactive power market. The uncertainty of generating units in the form of system contingencies are considered in the reactive power market-clearing procedure by the stochastic model in two steps. The Monte-Carlo Simulation (MCS) is first used to generate random scenarios. Then, in the second step, the stochastic market-clearing procedure is implemented as a series of deterministic optimization problems (scenarios) including non-contingent scenario and different post-contingency states. In each of these deterministic optimization problems, the objective function is total payment function (TPF) of generators which refers to the payment paid to the generators for their reactive power compensation. The effectiveness of the proposed model is examined based on the IEEE 24-bus Reliability Test System (IEEE 24-bus RTS). (author)

  5. Characteristics of a reactor with power reactivity feedback

    International Nuclear Information System (INIS)

    Li Fengyu; Zhang Yusheng; Zhang Guangfu; Liu Ying

    2008-01-01

    The point-reactor model with power reactivity feedback becomes a nonlinear system. Its dynamic characteristic shows great complexity. According to the mathematic definition of stability in differential equation qualitative theory, the model of a reactor with power reactivity feedback is judged unstable. The equilibrium point is a saddle-node point. A portion of the trajectory in the neighborhood of the equilibrium point is parabolic fan curve, and the other is hyperbolic fan curve. Based on phase locus near the equilibrium point, it is pointed out that the model is still stable within physical limits. The difference between stabilities in the mathematical sense and in the physical sense is indicated. (authors)

  6. Reactive adsorption: A cleaner technology in nuclear power plants

    International Nuclear Information System (INIS)

    Marton, G.; Szanya, T.; Hanak, L.

    1996-01-01

    Cleaner technology prefers work with minimal loss and the wastes cause the less environmental damages. In the spirit of the previous sentence in the present paper reactive adsorption is investigated for the removal of radioactive nuclides from nuclear power plant decontamination solutions. During alkaline, oxidative decontamination of nuclear power plant equipment a radioactive solution is produced. Owing to the storing difficulties of radioactive solutions it is necessary to develop a method for the in situ treatment of radioactive, alkaline, oxidative decontamination solutions, and for the concentration of radioactive components. Reactive adsorption seems to be promising for this purpose. 3 refs., 8 figs., 1 tab

  7. Single-Phase Boost Inverter-Based Electric Vehicle Charger With Integrated Vehicle to Grid Reactive Power Compensation

    DEFF Research Database (Denmark)

    Wickramasinghe Abeywardana, Damith Buddika; Acuna, Pablo; Hredzak, Branislav

    2018-01-01

    Vehicle to grid (V2G) reactive power compensation using electric vehicle (EV) onboard chargers helps to ensure grid power quality by achieving unity power factor operation. However, the use of EVs for V2G reactive power compensation increases the second-order harmonic ripple current component...... from the grid, exposes the EV battery to these undesirable ripple current components for a longer period and discharges the battery due to power conversion losses. This paper presents a way to provide V2G reactive power compensation through a boost inverter-based single stage EV charger and a DC...

  8. Reactive Power Pricing Model Considering the Randomness of Wind Power Output

    Science.gov (United States)

    Dai, Zhong; Wu, Zhou

    2018-01-01

    With the increase of wind power capacity integrated into grid, the influence of the randomness of wind power output on the reactive power distribution of grid is gradually highlighted. Meanwhile, the power market reform puts forward higher requirements for reasonable pricing of reactive power service. Based on it, the article combined the optimal power flow model considering wind power randomness with integrated cost allocation method to price reactive power. Meanwhile, considering the advantages and disadvantages of the present cost allocation method and marginal cost pricing, an integrated cost allocation method based on optimal power flow tracing is proposed. The model realized the optimal power flow distribution of reactive power with the minimal integrated cost and wind power integration, under the premise of guaranteeing the balance of reactive power pricing. Finally, through the analysis of multi-scenario calculation examples and the stochastic simulation of wind power outputs, the article compared the results of the model pricing and the marginal cost pricing, which proved that the model is accurate and effective.

  9. Reactivity calculation with reduction of the nuclear power fluctuations

    International Nuclear Information System (INIS)

    Suescun Diaz, Daniel; Senra Martinez, Aquilino

    2009-01-01

    A new formulation is presented in this paper for the calculation of reactivity, which is simpler than the formulation that uses the Laplace and Z transforms. A treatment is also made to reduce the intensity of the noise found in the nuclear power signal used in the calculation of reactivity. Two classes of different filters are used for that. This treatment is based on the fact that the reactivity can be written by using the compose Simpson's rule resulting in a sum of two convolution terms with response to the impulse that is characteristic of a linear system. The linear part is calculated by using the filter named finite impulse response filter (FIR). The non-linear part is calculated using the filter exponentially adjusted by the least squares method, which does not cause attenuation in the reactivity calculation.

  10. Reactivity calculation with reduction of the nuclear power fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Suescun Diaz, Daniel [COPPE/UFRJ, Programa de Engenharia Nuclear, Caixa Postal 68509, CEP 21941-914 RJ (Brazil)], E-mail: dsuescun@hotmail.com; Senra Martinez, Aquilino [COPPE/UFRJ, Programa de Engenharia Nuclear, Caixa Postal 68509, CEP 21941-914 RJ (Brazil)

    2009-05-15

    A new formulation is presented in this paper for the calculation of reactivity, which is simpler than the formulation that uses the Laplace and Z transforms. A treatment is also made to reduce the intensity of the noise found in the nuclear power signal used in the calculation of reactivity. Two classes of different filters are used for that. This treatment is based on the fact that the reactivity can be written by using the compose Simpson's rule resulting in a sum of two convolution terms with response to the impulse that is characteristic of a linear system. The linear part is calculated by using the filter named finite impulse response filter (FIR). The non-linear part is calculated using the filter exponentially adjusted by the least squares method, which does not cause attenuation in the reactivity calculation.

  11. Dynamic Reactive Power Compensation of Large Scale Wind Integrated Power System

    DEFF Research Database (Denmark)

    Rather, Zakir Hussain; Chen, Zhe; Thøgersen, Paul

    2015-01-01

    wind turbines especially wind farms with additional grid support functionalities like dynamic support (e,g dynamic reactive power support etc.) and ii) refurbishment of existing conventional central power plants to synchronous condensers could be one of the efficient, reliable and cost effective option......Due to progressive displacement of conventional power plants by wind turbines, dynamic security of large scale wind integrated power systems gets significantly compromised. In this paper we first highlight the importance of dynamic reactive power support/voltage security in large scale wind...... integrated power systems with least presence of conventional power plants. Then we propose a mixed integer dynamic optimization based method for optimal dynamic reactive power allocation in large scale wind integrated power systems. One of the important aspects of the proposed methodology is that unlike...

  12. Reactive Power Impact on Lifetime Prediction of Two-level Wind Power Converter

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Lau, M.

    2013-01-01

    The influence of reactive power injection on the dominating two-level wind power converter is investigated and compared in terms of power loss and thermal behavior. Then the lifetime of both the partial-scale and full-scale power converter is estimated based on the widely used Coffin-Manson model...

  13. Operational experience with reactive power control methods optimized for tokamak power supplies

    International Nuclear Information System (INIS)

    Sihler, C.; Huart, M.; Kaesemann, C.-P.; Streibl, B.

    2003-01-01

    The power and energy of the ASDEX Upgrade (AUG) tokamak are provided by two separate 10.5 kV, 110-85 Hz networks based on the flywheel generators EZ3-EZ4 in addition to the generator EZ2 dedicated to the toroidal field coil. The 10.5 kV networks supply the thyristor converters allowing fast control of the DC currents in the AUG poloidal field coils. Two methods for improving the load power factor in the present experimental campaign of AUG have been investigated, namely the control of the phase-to-neutral voltage in thyristor converters fitted with neutral thyristors, such as the new 145 MVA modular thyristor converter system (Group 6), and reactive power control achieved by means of static VAr compensators (SVC). The paper shows that reliable compensation up to 90 MVAr was regularly achieved and that electrical transients in SVC modules can be kept at an acceptable level. The paper will discuss the results from the reactive power reduction by SVC and neutral thyristor control and draw a comparative conclusion

  14. Coupled energy and reactive power market clearing considering power system security

    International Nuclear Information System (INIS)

    Rabiee, Abdorreza; Shayanfar, Heidarali; Amjady, Nima

    2009-01-01

    In a deregulated environment, when talking about electricity markets, one usually refers to energy market, paying less attention to the reactive power market. Active and reactive powers are, however, coupled through the AC power flow equations and branch loading limits as well as the synchronous generators capability curves. However, the sequential approach for energy and reactive power markets cannot present the optimal solution due to the interactions between these markets. For instance, clearing of the reactive power market can change active power dispatch (e.g. due to a change of transmission system losses and the capability curve limitation), which can lead to degradation of the energy market clearing point. This paper presents a coupled day ahead energy and reactive power market based on the pay-at-MCP settlement mechanism. Besides, the proposed coupled framework considers voltage stability and security issues and branch loading limits. The coupled market is cleared through optimal power flow (OPF). Its objective function includes total payment of generating units for their active power production along with the total payment function (TPF) of units for their reactive power compensation. Moreover, lost opportunity cost (LOC) of the units is also considered. The effectiveness of the proposed framework is examined on the IEEE 24 bus Reliability Test System

  15. Coupled energy and reactive power market clearing considering power system security

    Energy Technology Data Exchange (ETDEWEB)

    Rabiee, Abdorreza; Shayanfar, Heidarali [Center of Excellence for Power System Automation and Operation, Electrical Engineering Department, Iran University of Science and Technology (IUST), Tehran (Iran); Amjady, Nima [Department of Electrical Engineering, Semnan University, Semnan (Iran)

    2009-04-15

    In a deregulated environment, when talking about electricity markets, one usually refers to energy market, paying less attention to the reactive power market. Active and reactive powers are, however, coupled through the AC power flow equations and branch loading limits as well as the synchronous generators capability curves. However, the sequential approach for energy and reactive power markets cannot present the optimal solution due to the interactions between these markets. For instance, clearing of the reactive power market can change active power dispatch (e.g. due to a change of transmission system losses and the capability curve limitation), which can lead to degradation of the energy market clearing point. This paper presents a coupled day ahead energy and reactive power market based on the pay-at-MCP settlement mechanism. Besides, the proposed coupled framework considers voltage stability and security issues and branch loading limits. The coupled market is cleared through optimal power flow (OPF). Its objective function includes total payment of generating units for their active power production along with the total payment function (TPF) of units for their reactive power compensation. Moreover, lost opportunity cost (LOC) of the units is also considered. The effectiveness of the proposed framework is examined on the IEEE 24 bus Reliability Test System. (author)

  16. Dynamic Performance of the ITER Reactive Power Compensation System

    International Nuclear Information System (INIS)

    Sheng Zhicai; Fu Peng; Xu Liuwei

    2011-01-01

    Dynamic performance of a reactive power compensation (RPC) system for the international thermonuclear experimental reactor (ITER) power supply is presented. Static var compensators (SVCs) are adopted to mitigate voltage fluctuation and reduce the reactive power down to a level acceptable for the French/European 400 kV grid. A voltage feedback and load power feedforward controller for SVC is proposed, with the feedforward loop intended to guarantee short response time and the feedback loop ensuring good dynamics and steady characteristics of SVC. A mean filter was chosen to measure the control signals to improve the dynamic response. The dynamic performance of the SVC is verified by simulations using PSCAD/EMTDC codes.

  17. Local Dynamic Reactive Power for Correction of System Voltage Problems

    Energy Technology Data Exchange (ETDEWEB)

    Kueck, John D [ORNL; Rizy, D Tom [ORNL; Li, Fangxing [ORNL; Xu, Yan [ORNL; Li, Huijuan [University of Tennessee, Knoxville (UTK); Adhikari, Sarina [ORNL; Irminger, Philip [ORNL

    2008-12-01

    Distribution systems are experiencing outages due to a phenomenon known as local voltage collapse. Local voltage collapse is occurring in part because modern air conditioner compressor motors are much more susceptible to stalling during a voltage dip than older motors. These motors can stall in less than 3 cycles (.05s) when a fault, such as on the sub-transmission system, causes voltage to sag to 70 to 60%. The reasons for this susceptibility are discussed in the report. During the local voltage collapse, voltages are depressed for a period of perhaps one or two minutes. There is a concern that these local events are interacting together over larger areas and may present a challenge to system reliability. An effective method of preventing local voltage collapse is the use of voltage regulation from Distributed Energy Resources (DER) that can supply or absorb reactive power. DER, when properly controlled, can provide a rapid correction to voltage dips and prevent motor stall. This report discusses the phenomenon and causes of local voltage collapse as well as the control methodology we have developed to counter voltage sag. The problem is growing because of the use of low inertia, high efficiency air conditioner (A/C) compressor motors and because the use of electric A/C is growing in use and becoming a larger percentage of system load. A method for local dynamic voltage regulation is discussed which uses reactive power injection or absorption from local DER. This method is independent, rapid, and will not interfere with conventional utility system voltage control. The results of simulations of this method are provided. The method has also been tested at the ORNL s Distributed Energy Communications and Control (DECC) Laboratory using our research inverter and synchronous condenser. These systems at the DECC Lab are interconnected to an actual distribution system, the ORNL distribution system, which is fed from TVA s 161kV sub-transmission backbone. The test results

  18. Autonomous Active and Reactive Power Distribution Strategy in Islanded Microgrids

    DEFF Research Database (Denmark)

    Wu, Dan; Tang, Fen; Guerrero, Josep M.

    2014-01-01

    This paper proposes an autonomous active and reactive power distribution strategy that can be applied directly on current control mode (CCM) inverters, being compatible as well with conventional droop-controlled voltage control mode (VCM) converters. In a microgrid, since renewable energy sources...

  19. Power and reactive power simultaneous control by 0.5 MJ superconducting magnet energy storage

    International Nuclear Information System (INIS)

    Ise, Toshifumi; Tsuji, Kiichiro; Murakami, Yoshishige

    1984-01-01

    Superconducting magnet energy storage (SMES) is expected to be widely applied to the pulsed sources for fusion reactor research and to the energy storage substituting for pumping-up power stations, because of its fast energy storing and discharging and very high efficiency. Some results have been obtained so far. In this paper, however, the simultaneous control of power and reactive power is considered for an energy storage composed of two sets of thyristorized power conversion system and superconducting magnets in series connection, and a direct digital control system is described on the principle, design and configuration including the compensator, and on the experiment using the 0.5 MJ superconducting magnet energy storage installed in the Superconduction Engineering Experiment Center, Osaka University. The results obtained are as follows: (1) P control priority mode and Q control priority mode (in which power and reactive power control has priority, respectively) were proposed as the countermeasures when the simultaneous control of power and reactive power became impossible; (2) the design method was established, by which power and reactive power control loops can independently be designed as a result of simulation; (3) the achievement of the simultaneous control of power and reactive power was confirmed by using P-control priority mode and Q-control priority mode, in the experiment using the control system designed by simulation. The validity of simulation model was also confirmed by actual response waveforms. (Wakatsuki, Y.)

  20. An iterative method for controlling reactive power flow in boundary transformers

    Energy Technology Data Exchange (ETDEWEB)

    Trigo, Angel L.; Martinez, Jose L.; Riquelme, Jesus; Romero, Esther [Department of Electrical Engineering, University of Seville (Spain)

    2011-02-15

    This paper presents an operational tool designed to help the system operator to control the reactive power flow in transmission-subtransmission boundary transformers. The main objective is to determine the minimum number of control actions necessary to ensure that reactive power flows in transmission/subtransmission transformers remain within limits. The proposed iterative procedure combines the use of a linear programming problem and a load flow tool. The linear programming assumes a linear behaviour between dependent and control variables around an operating point, modelled with sensitivities. Experimental results regarding IEEE systems are provided comparing the performance of the proposed approach with that of a conventional optimal power flow. (author)

  1. Modelling and automatic reactive power control of isolated wind-diesel hybrid power systems using ANN

    International Nuclear Information System (INIS)

    Bansal, R.C.

    2008-01-01

    This paper presents an artificial neural network (ANN) based approach to tune the parameters of the static var compensator (SVC) reactive power controller over a wide range of typical load model parameters. The gains of PI (proportional integral) based SVC are optimised for typical values of the load voltage characteristics (n q ) by conventional techniques. Using the generated data, the method of multi-layer feed forward ANN with error back propagation training is employed to tune the parameters of the SVC. An ANN tuned SVC controller has been applied to control the reactive power of a variable slip/speed isolated wind-diesel hybrid power system. It is observed that the maximum deviations of all parameters are more for larger values of n q . It has been shown that initially synchronous generator supplies the reactive power required by the induction generator and/or load, and the latter reactive power is purely supplied by the SVC

  2. Modelling and automatic reactive power control of isolated wind-diesel hybrid power systems using ANN

    Energy Technology Data Exchange (ETDEWEB)

    Bansal, R.C. [Electrical and Electronics Engineering Division, School of Engineering and Physics, The University of the South Pacific, Suva (Fiji)

    2008-02-15

    This paper presents an artificial neural network (ANN) based approach to tune the parameters of the static var compensator (SVC) reactive power controller over a wide range of typical load model parameters. The gains of PI (proportional integral) based SVC are optimised for typical values of the load voltage characteristics (n{sub q}) by conventional techniques. Using the generated data, the method of multi-layer feed forward ANN with error back propagation training is employed to tune the parameters of the SVC. An ANN tuned SVC controller has been applied to control the reactive power of a variable slip/speed isolated wind-diesel hybrid power system. It is observed that the maximum deviations of all parameters are more for larger values of n{sub q}. It has been shown that initially synchronous generator supplies the reactive power required by the induction generator and/or load, and the latter reactive power is purely supplied by the SVC. (author)

  3. Reliability Analysis of Single-Phase PV Inverters with Reactive Power Injection at Night Considering Mission Profiles

    DEFF Research Database (Denmark)

    Anurag, Anup; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    loading, considering the operation outside active feed-in hours. An analytical lifetime model is then employed for lifetime quantization based on the Palgrem Miner rule. Thereafter, considering the lifetime reduction of the PV inverter under different mission profiles with reactive power injection......The widespread adoption of mixed renewables urgently require reactive power exchange at various feed-in points of the utility grid. Photovoltaic (PV) inverters are able to provide reactive power in a decentralized manner at the grid-connection points even outside active power feed-in operation......, especially at night when there is no solar irradiance. This serves as a motivation for utilizing the PV inverters at night for reactive power compensation. Thus, an analysis on the impact of reactive power injection by PV inverters outside feed-in operation on the thermal performance and the reliability has...

  4. THE IMPACT OF POWER COEFFICIENT OF REACTIVITY ON CANDU 6 REACTORS

    Directory of Open Access Journals (Sweden)

    D. KASTANYA

    2013-10-01

    Full Text Available The combined effects of reactivity coefficients, along with other core nuclear characteristics, determine reactor core behavior in normal operation and accident conditions. The Power Coefficient of Reactivity (PCR is an aggregate indicator representing the change in reactor core reactivity per unit change in reactor power. It is an integral quantity which captures the contributions of the fuel temperature, coolant void, and coolant temperature reactivity feedbacks. All nuclear reactor designs provide a balance between their inherent nuclear characteristics and the engineered reactivity control features, to ensure that changes in reactivity under all operating conditions are maintained within a safe range. The CANDU® reactor design takes advantage of its inherent nuclear characteristics, namely a small magnitude of reactivity coefficients, minimal excess reactivity, and very long prompt neutron lifetime, to mitigate the demand on the engineered systems for controlling reactivity and responding to accidents. In particular, CANDU reactors have always taken advantage of the small value of the PCR associated with their design characteristics, such that the overall design and safety characteristics of the reactor are not sensitive to the value of the PCR. For other reactor design concepts a PCR which is both large and negative is an important aspect in the design of their engineered systems for controlling reactivity. It will be demonstrated that during Loss of Regulation Control (LORC and Large Break Loss of Coolant Accident (LBLOCA events, the impact of variations in power coefficient, including a hypothesized larger than estimated PCR, has no safety-significance for CANDU reactor design. Since the CANDU 6 PCR is small, variations in the range of values for PCR on the performance or safety of the reactor are not significant.

  5. Application of Newton's optimal power flow in voltage/reactive power control

    Energy Technology Data Exchange (ETDEWEB)

    Bjelogrlic, M.; Babic, B.S. (Electric Power Board of Serbia, Belgrade (YU)); Calovic, M.S. (Dept. of Electrical Engineering, University of Belgrade, Belgrade (YU)); Ristanovic, P. (Institute Nikola Tesla, Belgrade (YU))

    1990-11-01

    This paper considers an application of Newton's optimal power flow to the solution of the secondary voltage/reactive power control in transmission networks. An efficient computer program based on the latest achievements in the sparse matrix/vector techniques has been developed for this purpose. It is characterized by good robustness, accuracy and speed. A combined objective function appropriate for various system load levels with suitable constraints, for treatment of the power system security and economy is also proposed. For the real-time voltage/reactive power control, a suboptimal power flow procedure has been derived by using the reduced set of control variables. This procedure is based on the sensitivity theory applied to the determination of zones for the secondary voltage/reactive power control and corresponding reduced set of regulating sources, whose reactive outputs represent control variables in the optimal power flow program. As a result, the optimal power flow program output becomes a schedule to be used by operators in the process of the real-time voltage/reactive power control in both normal and emergency operating states.

  6. Optimum Arrangement of Reactive Power Sources While Using Genetic Algori

    Directory of Open Access Journals (Sweden)

    A. M. Gashimov

    2010-01-01

    Full Text Available Reduction of total losses in distribution electricity supply network is considered as an important measure which serves for improvement of efficiency of electric power supply systems. This objective can be achieved by optimum distribution of reactive power sources in proper places of distribution electricity supply network. The proposed methodology is based on application of a genetic algorithm. Total expenses for installation of capacitor banks, their operation and also expenses related to electric power losses are considered as an efficiency function which is used for determination of places with optimum values of capacitor bank power. The methodology is the most efficient for selection of optimum places in the network where it is necessary to install capacitor banks with due account of their power control depending on a switched-on load value in the units.

  7. Device for measuring active, reactive and apparent power

    Energy Technology Data Exchange (ETDEWEB)

    Bartosinski, E.; Wieland, J.

    1982-09-30

    The plan consists of a traditional electrodynamic mechanism for measuring power (IM) supplemented by three switches, two rectifiers, resistor, included in parallel, and phaseshifting throttle included in series with the voltage coil of the IM. This makes it possible by selection to perform three types of measurements: active power of alternating current or power of direct current, only the voltage coils and the IM current are engaged; reactive power, the resistor and the throttle are additionally engaged by the aforementioned method; complete (apparent) power--the current and the voltage are supplied directly to the IM coils, but in contrast to the first case, through rectifiers. The influence of the highest harmonic components of voltage and current which are not significant for industrial measurements can be eliminated in necessary cases using filtering devices.

  8. Stochastic reactive power dispatch in hybrid power system with intermittent wind power generation

    International Nuclear Information System (INIS)

    Taghavi, Reza; Seifi, Ali Reza; Samet, Haidar

    2015-01-01

    Environmental concerns besides fuel costs are the predominant reasons for unprecedented escalating integration of wind turbine on power systems. Operation and planning of power systems are affected by this type of energy due to the intermittent nature of wind speed inputs with high uncertainty in the optimization output variables. Consequently, in order to model this high inherent uncertainty, a PRPO (probabilistic reactive power optimization) framework should be devised. Although MC (Monte-Carlo) techniques can solve the PRPO with high precision, PEMs (point estimate methods) can preserve the accuracy to attain reasonable results when diminishing the computational effort. Also, this paper introduces a methodology for optimally dispatching the reactive power in the transmission system, while minimizing the active power losses. The optimization problem is formulated as a LFP (linear fuzzy programing). The core of the problem lay on generation of 2m + 1 point estimates for solving PRPO, where n is the number of input stochastic variables. The proposed methodology is investigated using the IEEE-14 bus test system equipped with HVDC (high voltage direct current), UPFC (unified power flow controller) and DFIG (doubly fed induction generator) devices. The accuracy of the method is demonstrated in the case study. - Highlights: • This paper uses stochastic loads in optimization process. • AC–DC load flow is modified to use some advantages of DC part in optimization process. • UPFC and DFIG are simulated in a way that could be effective in optimization process. • Fuzzy set has been used as an uncertainty analysis tool in the optimization

  9. Wolf Search Algorithm for Solving Optimal Reactive Power Dispatch Problem

    Directory of Open Access Journals (Sweden)

    Kanagasabai Lenin

    2015-03-01

    Full Text Available This paper presents a new bio-inspired heuristic optimization algorithm called the Wolf Search Algorithm (WSA for solving the multi-objective reactive power dispatch problem. Wolf Search algorithm is a new bio – inspired heuristic algorithm which based on wolf preying behaviour. The way wolves search for food and survive by avoiding their enemies has been imitated to formulate the algorithm for solving the reactive power dispatches. And the speciality  of wolf is  possessing  both individual local searching ability and autonomous flocking movement and this special property has been utilized to formulate the search algorithm .The proposed (WSA algorithm has been tested on standard IEEE 30 bus test system and simulation results shows clearly about the good performance of the proposed algorithm .

  10. Modified artificial bee colony algorithm for reactive power optimization

    Science.gov (United States)

    Sulaiman, Noorazliza; Mohamad-Saleh, Junita; Abro, Abdul Ghani

    2015-05-01

    Bio-inspired algorithms (BIAs) implemented to solve various optimization problems have shown promising results which are very important in this severely complex real-world. Artificial Bee Colony (ABC) algorithm, a kind of BIAs has demonstrated tremendous results as compared to other optimization algorithms. This paper presents a new modified ABC algorithm referred to as JA-ABC3 with the aim to enhance convergence speed and avoid premature convergence. The proposed algorithm has been simulated on ten commonly used benchmarks functions. Its performance has also been compared with other existing ABC variants. To justify its robust applicability, the proposed algorithm has been tested to solve Reactive Power Optimization problem. The results have shown that the proposed algorithm has superior performance to other existing ABC variants e.g. GABC, BABC1, BABC2, BsfABC dan IABC in terms of convergence speed. Furthermore, the proposed algorithm has also demonstrated excellence performance in solving Reactive Power Optimization problem.

  11. Reactive power interconnection requirements for PV and wind plants : recommendations to NERC.

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, Jason (General Electric, Schenectady, NY); Walling, Reigh (General Electric, Schenectady, NY); Peter, William (SunPower, Richmond, CA); Von Engeln, Edi (NV Energy, Reno, NV); Seymour, Eric (AEI, Fort Collins, CO); Nelson, Robert (Siemens Wind Turbines, Orlando, FL); Casey, Leo (Satcon, Boston, MA); Ellis, Abraham; Barker, Chris. (SunPower, Richmond, CA)

    2012-02-01

    Voltage on the North American bulk system is normally regulated by synchronous generators, which typically are provided with voltage schedules by transmission system operators. In the past, variable generation plants were considered very small relative to conventional generating units, and were characteristically either induction generator (wind) or line-commutated inverters (photovoltaic) that have no inherent voltage regulation capability. However, the growing level of penetration of non-traditional renewable generation - especially wind and solar - has led to the need for renewable generation to contribute more significantly to power system voltage control and reactive power capacity. Modern wind-turbine generators, and increasingly PV inverters as well, have considerable dynamic reactive power capability, which can be further enhanced with other reactive support equipment at the plant level to meet interconnection requirements. This report contains a set of recommendations to the North-America Electricity Reliability Corporation (NERC) as part of Task 1-3 (interconnection requirements) of the Integration of Variable Generation Task Force (IVGTF) work plan. The report discusses reactive capability of different generator technologies, reviews existing reactive power standards, and provides specific recommendations to improve existing interconnection standards.

  12. PROVIDING QUALITY OF ELECTRIC POWER IN ELECTRIC POWER SYSTEM IN PARALLEL OPERATION WITH WIND TURBINE

    Directory of Open Access Journals (Sweden)

    Yu. A. Rolik

    2016-01-01

    Full Text Available The problem of providing electric power quality in the electric power systems (EPS that are equipped with sufficiently long air or cable transmission lines is under consideration. This problem proved to be of particular relevance to the EPS in which a source of electrical energy is the generator of wind turbines since the wind itself is an instable primary energy source. Determination of the degree of automation of voltage regulation in the EPS is reduced to the choice of methods and means of regulation of power quality parameters. The concept of a voltage loss and the causes of the latter are explained by the simplest power system that is presented by a single-line diagram. It is suggested to regulate voltage by means of changing parameters of the network with the use of the method of reducing loss of line voltage by reducing its reactance. The latter is achieved by longitudinal capacitive compensation of the inductive reactance of the line. The effect is illustrated by vector diagrams of currents and voltages in the equivalent circuits of transmission lines with and without the use of longitudinal capacitive compensation. The analysis of adduced formulas demonstrated that the use of this method of regulation is useful only in the systems of power supply with a relatively low power factor (cosφ < 0.7 to 0.9. This power factor is typical for the situation of inclusion the wind turbine with asynchronous generator in the network since the speed of wind is instable. The voltage regulation fulfilled with the aid of the proposed method will make it possible to provide the required quality of the consumers’ busbars voltage in this situation. In is turn, it will make possible to create the necessary conditions for the economical transmission of electric power with the lowest outlay of reactive power and the lowest outlay of active power losses.

  13. A Hierarchical Modeling for Reactive Power Optimization With Joint Transmission and Distribution Networks by Curve Fitting

    DEFF Research Database (Denmark)

    Ding, Tao; Li, Cheng; Huang, Can

    2018-01-01

    –slave structure and improves traditional centralized modeling methods by alleviating the big data problem in a control center. Specifically, the transmission-distribution-network coordination issue of the hierarchical modeling method is investigated. First, a curve-fitting approach is developed to provide a cost......In order to solve the reactive power optimization with joint transmission and distribution networks, a hierarchical modeling method is proposed in this paper. It allows the reactive power optimization of transmission and distribution networks to be performed separately, leading to a master...... optimality. Numerical results on two test systems verify the effectiveness of the proposed hierarchical modeling and curve-fitting methods....

  14. Simplified reactive power management strategy for complex power grids under stochastic operation and incomplete information

    International Nuclear Information System (INIS)

    Vlachogiannis, John G.

    2009-01-01

    In the current released energy market, the large-scale complex transmission networks and the distribution ones with dispersed energy sources and 'intelligent' components operate under uncertainties, stochastic and prior incomplete information. A safe and reliable operation of such complex power grids is a major issue for system operators. Under these circumstances an online reactive power management strategy with minimum risk concerning all uncertain and stochastic parameters is proposed. Therefore, new concepts such as reactive power-weighted node-to-node linking and reactive power control capability are introduced. A distributed and interconnected stochastic learning automata system is implemented to manage, in a unified and unique way, the reactive power in complex power grids with stochastic reactive power demand and detect the vulnerable part. The proposed simplified strategy can also consider more stochastic aspects such as variable grid's topology. Results of the proposed strategy obtained on the networks of IEEE 30-bus and IEEE 118-bus systems demonstrate the effectiveness of the proposed strategy.

  15. Loss Minimizing Operation of Doubly Fed Induction Generator Based Wind Generation Systems Considering Reactive Power Provision

    DEFF Research Database (Denmark)

    Baohua, Zhang; Hu, Weihao; Chen, Zhe

    2014-01-01

    The paper deals with control techniques for minimizing the operating loss of doubly fed induction generator based wind generation systems when providing reactive power. The proposed method achieves its goal through controlling the rotor side q-axis current in the synchronous reference frame...

  16. Reactive power control of wind farm using facts devices

    International Nuclear Information System (INIS)

    Ashfaq, S.; Arif, A.; Shakeel, A.; Mahmood, T.

    2014-01-01

    Wind energy is an attainable option to complement other types of pollution-free green generation Grid connections of renewable energy resources are vital if they are to be effectively exploited, but grid connection brings problems of voltage fluctuation and harmonic distortion. FACTs devices are one of the power electronics revolutions to improve voltage profile, system stability, and reactive power control and to reduce transmission losses. The studied system here is a variable speed wind generation system based on Induction Generator (IG) with integration of different FACTs controllers in the wind farm. To harness the wind power efficiently the most reliable and expensive system in the present era is grid connected doubly fed induction generator. Induction generator with FACTs devices is a suitable economical replacement. The suggested scheme is implemented in MATLAB Simulink with real time parameters of GHARO wind power plant in Sind, and corresponding results and output waveforms proves the potential strength of proposed methodology. (author)

  17. Ancillary services provided by PV power plants

    Directory of Open Access Journals (Sweden)

    Antonio PIERNO

    2016-07-01

    Full Text Available Renewable energy sources are widely utilized in distributed generation systems, and, recently, they are also considered for providing ancillary services. The paper is focused on PV plants, a survey of the most interesting papers published in the literature in the last decade is reported and the main characteristics of the technical proposals, with their advantages and limits, are evidenced. The results are schematically shown in a table that immediately gives the opportunity to be aware of what was already done, representing a reference tool.

  18. A Hybrid Optimization Method for Reactive Power and Voltage Control Considering Power Loss Minimization

    DEFF Research Database (Denmark)

    Liu, Chengxi; Qin, Nan; Bak, Claus Leth

    2015-01-01

    This paper proposes a hybrid optimization method to optimally control the voltage and reactive power with minimum power loss in transmission grid. This approach is used for the Danish automatic voltage control (AVC) system which is typically a non-linear non-convex problem mixed with both...

  19. A Preliminary Analysis of the Economics of Using Distributed Energy as a Source of Reactive Power Supply

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fangxing [ORNL; Kueck, John D [ORNL; Rizy, D Tom [ORNL; King, Thomas F [ORNL

    2006-04-01

    A major blackout affecting 50 million people in the Northeast United States, where insufficient reactive power supply was an issue, and an increased number of filings made to the Federal Energy Regulatory Commission by generators for reactive power has led to a closer look at reactive power supply and compensation. The Northeastern Massachusetts region is one such area where there is an insufficiency in reactive power compensation. Distributed energy due to its close proximity to loads seems to be a viable option for solving any present or future reactive power shortage problems. Industry experts believe that supplying reactive power from synchronized distributed energy sources can be 2 to 3 times more effective than providing reactive support in bulk from longer distances at the transmission or generation level. Several technology options are available to supply reactive power from distributed energy sources such as small generators, synchronous condensers, fuel cells or microturbines. In addition, simple payback analysis indicates that investments in DG to provide reactive power can be recouped in less than 5 years when capacity payments for providing reactive power are larger than $5,000/kVAR and the DG capital and installation costs are lower than $30/kVAR. However, the current institutional arrangements for reactive power compensation present a significant barrier to wider adoption of distributed energy as a source of reactive power. Furthermore, there is a significant difference between how generators and transmission owners/providers are compensated for reactive power supplied. The situation for distributed energy sources is even more difficult, as there are no arrangements to compensate independent DE owners interested in supplying reactive power to the grid other than those for very large IPPs. There are comparable functionality barriers as well, as these smaller devices do not have the control and communications requirements necessary for automatic

  20. Regulating power provided by an industrial virtual power plant

    NARCIS (Netherlands)

    Roossien, B.; Kamphuis, I.G.; Doss, A.

    2012-01-01

    The use of renewable energy sources for the transition towards a sustainable electricity system imposes a number of new challenges for the grid, one of them being the balancing of variable output supply and demand. The flexibility of production and consumption in Virtual Power Plants can be used

  1. Blind spot in free power market debate. Reactive power problems are unavoidable

    International Nuclear Information System (INIS)

    Maessen, T.

    2002-01-01

    Import restrictions, switching problems, remotely readable meters appear to be temporary problems in a liberalised power market, according to statement of the Dutch the government. However, the issues surrounding reactive power management in the Dutch transmission and distribution networks are of a far more fundamental nature. The import of cheap foreign electricity could overload the domestic power grid sufficiently to compromise the security of supply [nl

  2. Reactivity control of nuclear power reactors: new options

    International Nuclear Information System (INIS)

    Alcala, F.

    1984-01-01

    Some actual aspects (referring to economy, non-proliferation and environmental impact) of nuclear power reactors has been analyzed from the point of view of the reactivity control physics. Specially studied have been the physical mechanisms related with the spectral shift control method and their general positive effects on those aspects. The analysis carried out suggested the application of the above method of control to reactors with non-hydrogenous fuel cells, which are mainly characterized by their high moderator/fuel ratio. Finally three different types of such fuel cells are presented and some results about one of them (belonging to a PHWR controlled by graphite rods) are given. (author)

  3. Basic study on dynamic reactive-power control method with PV output prediction for solar inverter

    Directory of Open Access Journals (Sweden)

    Ryunosuke Miyoshi

    2016-01-01

    Full Text Available To effectively utilize a photovoltaic (PV system, reactive-power control methods for solar inverters have been considered. Among the various methods, the constant-voltage control outputs less reactive power compared with the other methods. We have developed a constant-voltage control to reduce the reactive-power output. However, the developed constant-voltage control still outputs unnecessary reactive power because the control parameter is constant in every waveform of the PV output. To reduce the reactive-power output, we propose a dynamic reactive-power control method with a PV output prediction. In the proposed method, the control parameter is varied according to the properties of the predicted PV waveform. In this study, we performed numerical simulations using a distribution system model, and we confirmed that the proposed method reduces the reactive-power output within the voltage constraint.

  4. Transport and Reactivity of Decontaminants to Provide Hazard Mitigation of Chemical Warfare Agents from Materials

    Science.gov (United States)

    2016-06-01

    2013 4. TITLE AND SUBTITLE Transport and Reactivity of Decontaminants to Provide Hazard Mitigation of Chemical Warfare Agents from Materials 5a...directions for future decontamination formulation approaches. 15. SUBJECT TERMS GD HD Decontamination Hazard mitigation VX Chemical warfare agent... DECONTAMINANTS TO PROVIDE HAZARD MITIGATION OF CHEMICAL WARFARE AGENTS FROM MATERIALS 1. INTRODUCTION Decontamination of materials is the

  5. Efficient Reactive Power Compensation Algorithm for Distribution Network

    Directory of Open Access Journals (Sweden)

    J. Jerome

    2017-12-01

    Full Text Available The use of automation and energy efficient equipment with electronic control would greatly improve industrial production.  These new devices are more sensitive to supply voltage deviation and the characteristics of the power system that was previously ignored are now very important. Hence the benefits of distribution automation have been widely acknowledged in recent years. This paper proposes an efficient load flow solution technique extended to find optimum location for reactive power compensation and network reconfiguration for planning and day-to-day operation of distribution networks.  This is required as a part of the distribution automation system (DAS for taking various control and operation decisions.  The method exploits the radial nature of the network and uses forward and backward propagation technique to calculate branch currents and node voltages.  The proposed method has been tested to analyze several practical distribution networks of various voltage levels and also having high R/X ratio.

  6. Economic analysis of reactive power compensation in a wind farm: Influence of Spanish energy policy

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, E.; Daroca, F. [Grupo Eolicas Riojanas, Carretera de Laguardia, 91-93, 26006 Logrono, La Rioja (Spain); Sanz, F.; Blanco, J. [Department of Mechanical Engineering, University of La Rioja, Logrono, La Rioja (Spain); Jimenez, E. [Department of Electrical Engineering, University of La Rioja, Logrono, La Rioja (Spain)

    2008-08-15

    Presently, renewable energies and especially wind energy are gaining a special relevance in the electrical market worldwide. This current rate of growth brings with it the need for the various wind farms to not limit themselves to producing energy but also provide stability to the network within its capabilities. So, the actual objective is to adapt the installations that produce wind energy in such a way that they give a maximum amount of support in any given moment to the electrical network. For this purpose, there are governing techno-economic parameters that influence the economic behavior of commercial wind farms. A complete cost-benefit analysis model is developed, focused on incorporating automatic capacitor banks into wind farms for the compensation of reactive power. This economic analysis is about doubly fed induction generator (DFIG) wind turbines. Although this kind of wind turbines have a certain capability in terms of modulating reactive power, this capacity is not enough to achieve the new requirements of reactive power regulation in Spain and it is necessary to invest in systems of external compensation. In this paper, we have studied the case of DFIG wind turbine and capacitor banks, although the used methodology can be applied to other technologies as well by simply amplifying the algorithms according to the specific characteristics of the option elected. Following this premise, a detailed analysis of the specific needs of a wind farm has been carried out, as well as a search for the optimum performance for the compensation of reactive power. (author)

  7. Economic analysis of reactive power compensation in a wind farm: Influence of Spanish energy policy

    International Nuclear Information System (INIS)

    Martinez, E.; Daroca, F.; Sanz, F.; Blanco, J.; Jimenez, E.

    2008-01-01

    Presently, renewable energies and especially wind energy are gaining a special relevance in the electrical market worldwide. This current rate of growth brings with it the need for the various wind farms to not limit themselves to producing energy but also provide stability to the network within its capabilities. So, the actual objective is to adapt the installations that produce wind energy in such a way that they give a maximum amount of support in any given moment to the electrical network. For this purpose, there are governing techno-economic parameters that influence the economic behavior of commercial wind farms. A complete cost-benefit analysis model is developed, focused on incorporating automatic capacitor banks into wind farms for the compensation of reactive power. This economic analysis is about doubly fed induction generator (DFIG) wind turbines. Although this kind of wind turbines have a certain capability in terms of modulating reactive power, this capacity is not enough to achieve the new requirements of reactive power regulation in Spain and it is necessary to invest in systems of external compensation. In this paper, we have studied the case of DFIG wind turbine and capacitor banks, although the used methodology can be applied to other technologies as well by simply amplifying the algorithms according to the specific characteristics of the option elected. Following this premise, a detailed analysis of the specific needs of a wind farm has been carried out, as well as a search for the optimum performance for the compensation of reactive power. (author)

  8. Stochastic reactive power market with volatility of wind power considering voltage security

    International Nuclear Information System (INIS)

    Kargarian, A.; Raoofat, M.

    2011-01-01

    While wind power generation is growing rapidly around the globe; its stochastic nature affects the system operation in many different aspects. In this paper, the impact of wind power volatility on the reactive power market is taken into account. The paper presents a novel stochastic method for optimal reactive power market clearing considering voltage security and volatile nature of the wind. The proposed optimization algorithm uses a multiobjective nonlinear programming technique to minimize market payment and simultaneously maximize voltage security margin. Considering a set of probable wind speeds, in the first stage, the proposed algorithm seeks to minimize expected system payment which is summation of reactive power payment and transmission loss cost. The object of the second stage is maximization of expected voltage security margin to increase the system loadability and security. Finally, in the last stage, a multiobjective function is presented to schedule the stochastic reactive power market using results of two previous stages. The proposed algorithm is applied to IEEE 14-bus test system. As a benchmark, Monte Carlo Simulation method is utilized to simulate the actual market of given period of time to evaluate results of the proposed algorithm, and satisfactory results are achieved. -- Highlights: →The paper proposes a new algorithm for stochastic reactive power market clearing. →The stochastic nature of the wind which impacts the system operation and market clearing process, is taken into account. →The paper suggests an expected voltage stability margin and optimizes it in conjunction with expected total market payment. →To clear the market with two mentioned objective functions, a three-stage multiobjective nonlinear programming is implemented. →Also, a simple method is suggested to determine a suitable priority coefficient between two individual objective functions.

  9. Application of the ant colony search algorithm to reactive power pricing in an open electricity market

    International Nuclear Information System (INIS)

    Ketabi, Abbas; Alibabaee, Ahmad; Feuillet, R.

    2010-01-01

    Reactive power management is essential to transfer real energy and support power system security. Developing an accurate and feasible method for reactive power pricing is important in the electricity market. In conventional optimal power flow models the production cost of reactive power was ignored. In this paper, the production cost of reactive power and investment cost of capacitor banks were included into the objective function of the OPF problem. Then, using ant colony search algorithm, the optimal problem was solved. Marginal price theory was used for calculation of the cost of active and reactive power at each bus in competitive electric markets. Application of the proposed method on IEEE 14-bus system confirms its validity and effectiveness. Results from several case studies show clearly the effects of various factors on reactive power price. (author)

  10. Reactive Power Injection Strategies for Single-Phase Photovoltaic Systems Considering Grid Requirements

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    .g. Germany and Italy. Those advanced features can be provided by next generation PV systems, and will be enhanced in the future to ensure an even efficient and reliable utilization of PV systems. In light of this, Reactive Power Injection (RPI) strategies for single-phase PV systems are explored...... in this paper. The RPI possibilities are: a) constant average active power control, b) constant active current control, c) constant peak current control and d) thermal optimized control strategy. All those strategies comply with the currently active grid codes, but are with different objectives. The proposed...... RPI strategies are demonstrated firstly by simulations and also tested experimentally on a 1 kW singe-phase grid-connected system in LVRT operation mode. Those results show the effectiveness and feasibilities of the proposed strategies with reactive power control during LVRT operation. The design...

  11. Reactive power influence on the thermal cycling of multi-MW wind power inverter

    DEFF Research Database (Denmark)

    Ma, Ke; Liserre, Marco; Blaabjerg, Frede

    2012-01-01

    converter system are first presented at different wind speeds. Furthermore, the interaction between paralleled converter systems in a wind park is also considered and analyzed. By controlling the reactive power circulated among paralleled converters, a new concept is then proposed to stabilize the thermal...

  12. Electrical engineering unit for the reactive power control of the load bus at the voltage instability

    Science.gov (United States)

    Kotenev, A. V.; Kotenev, V. I.; Kochetkov, V. V.; Elkin, D. A.

    2018-01-01

    For the purpose of reactive power control error reduction and decrease of the voltage sags in the electric power system caused by the asynchronous motors started the mathematical model of the load bus was developed. The model was built up of the sub-models of the following elements: a transformer, a transmission line, a synchronous and an asynchronous loads and a capacitor bank load, and represents the automatic reactive power control system taking into account electromagnetic processes of the asynchronous motors started and reactive power changing of the electric power system elements caused by the voltage fluctuation. The active power/time and reactive power/time characteristics based on the recommended procedure of the equivalent electric circuit parameters calculation were obtained. The derived automatic reactive power control system was shown to eliminate the voltage sags in the electric power system caused by the asynchronous motors started.

  13. Reactive power dispatch considering voltage stability with seeker optimization algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Chaohua; Chen, Weirong; Zhang, Xuexia [The School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Zhu, Yunfang [Department of Computer and Communication Engineering, E' mei Campus, Southwest Jiaotong University, E' mei 614202 (China)

    2009-10-15

    Optimal reactive power dispatch (ORPD) has a growing impact on secure and economical operation of power systems. This issue is well known as a non-linear, multi-modal and multi-objective optimization problem where global optimization techniques are required in order to avoid local minima. In the last decades, computation intelligence-based techniques such as genetic algorithms (GAs), differential evolution (DE) algorithms and particle swarm optimization (PSO) algorithms, etc., have often been used for this aim. In this work, a seeker optimization algorithm (SOA) based method is proposed for ORPD considering static voltage stability and voltage deviation. The SOA is based on the concept of simulating the act of human searching where search direction is based on the empirical gradient by evaluating the response to the position changes and step length is based on uncertainty reasoning by using a simple Fuzzy rule. The algorithm's performance is studied with comparisons of two versions of GAs, three versions of DE algorithms and four versions of PSO algorithms on the IEEE 57 and 118-bus power systems. The simulation results show that the proposed approach performed better than the other listed algorithms and can be efficiently used for the ORPD problem. (author)

  14. Microgrid Reactive and Harmonic Power Sharing Using Enhanced Virtual Impedance

    DEFF Research Database (Denmark)

    He, Jinwei; Wei Li, Yun; Guerrero, Josep M.

    2013-01-01

    To address the load sharing problem in islanding microgrids, this paper proposes an improved approach which regulates the distributed generation (DG) unit interfacing virtual impedance at fundamental and selected harmonic frequencies. In contrast to the conventional virtual impedance control where...... only a line current feed-forward term is added to the DG voltage reference, the proposed virtual impedances at fundamental and harmonic frequencies are realized using DG line current and point of common coupling (PCC) voltage feed-forward terms, respectively. With this modification, the mismatched DG...... feeder impedances can be properly compensated, resulting in accurate reactive and harmonic power sharing at the same time. In addition, this paper shows that the microgrid PCC harmonic voltages can be mitigated by reducing the magnitude of DG unit equivalent harmonic impedance. Finally, an improved...

  15. Robust Adaptive Reactive Power Control for Doubly Fed Induction Generator

    Directory of Open Access Journals (Sweden)

    Huabin Wen

    2014-01-01

    Full Text Available The problem of reactive power control for mains-side inverter (MSI in doubly fed induction generator (DFIG is studied in this paper. To accommodate the modelling nonlinearities and inherent uncertainties, a novel robust adaptive control algorithm for MSI is proposed by utilizing Lyapunov theory that ensures asymptotic stability of the system under unpredictable external disturbances and significant parametric uncertainties. The distinguishing benefit of the aforementioned scheme consists in its capabilities to maintain satisfactory performance under varying operation conditions without the need for manually redesigning or reprogramming the control gains in contrast to the commonly used PI/PID control. Simulations are also built to confirm the correctness and benefits of the control scheme.

  16. An islanding microgrid reactive power sharing scheme enhanced by programmed virtual impedances

    DEFF Research Database (Denmark)

    He, Jinwei; Li, Yun Wei; Guerrero, Josep M.

    2012-01-01

    harmonic currents. With the knowledge of feeder impedances, reactive power sharing performance can be enhanced by the regulation of DG unit output virtual impedance. The proposed method realizes accurate real and reactive power sharing in proportion to DG unit rated power. Simulated and experimental...

  17. Reactive Power Support of Electrical Vehicle Charging Station Upgraded with Flywheel Energy Storage System

    DEFF Research Database (Denmark)

    SUN, BO; Dragicevic, Tomislav; Savaghebi, Mehdi

    2015-01-01

    Electrical vehicles (EVs) are presenting increasingly potential to replace the conventional fossil fuel based vehicles due to environmental friendly characteristic. Accordingly, Charging Stations (CS), as an intermediate between grid and large numbers of EVs, are supposed to have more critical...... influence on future smart transportation network. This paper explores an off-board charging station upgraded with flywheel energy storage system that could provide a reactive power support to the grid utility. A supervisory control scheme based on distributed bus signaling is proposed to coordinate...... the operation of each component in the system. As a result, the charging station could supply the reactive power support to the utility grid without compromising the charging algorithm and preserve the battery’s lifetime. Finally, the real-time simulation results based on dSPACE1006 verifies the proposed...

  18. Distributed multi-agent scheme for reactive power management with renewable energy

    International Nuclear Information System (INIS)

    Rahman, M.S.; Mahmud, M.A.; Pota, H.R.; Hossain, M.J.

    2014-01-01

    Highlights: • A distributed multi-agent scheme is proposed to enhance the dynamic voltage stability. • A control agent is designed where control actions are performed through PI controller. • Proposed scheme is compared with the conventional approach with DSTATCOM. • Proposed scheme adapts the capability of estimation and control under various operating conditions. - Abstract: This paper presents a new distributed multi-agent scheme for reactive power management in smart coordinated distribution networks with renewable energy sources (RESs) to enhance the dynamic voltage stability, which is mainly based on controlling distributed static synchronous compensators (DSTATCOMs). The proposed control scheme is incorporated in a multi-agent framework where the intelligent agents simultaneously coordinate with each other and represent various physical models to provide information and energy flow among different physical processes. The reactive power is estimated from the topology of distribution networks and with this information, necessary control actions are performed through the proposed proportional integral (PI) controller. The performance of the proposed scheme is evaluated on a 8-bus distribution network under various operating conditions. The performance of the proposed scheme is validated through simulation results and these results are compared to that of conventional PI-based DSTATCOM control scheme. From simulation results, it is found that the distributed MAS provides excellence performance for improving voltage profiles by managing reactive power in a smarter way

  19. Advanced configuration of hybrid passive filter for reactive power and harmonic compensation

    OpenAIRE

    Kececioglu, O. Fatih; Acikgoz, Hakan; Sekkeli, Mustafa

    2016-01-01

    Harmonics is one of the major power quality problems for power systems. The harmonics can be eliminated by power filters such as passive, active, and hybrid. In this study, a new passive filter configuration has been improved in addition to the existing passive filter configurations. Conventional hybrid passive filters are not successful to compensate rapidly changing reactive power demand. The proposed configure are capable of compensating both harmonics and reactive power at the same time. ...

  20. Advanced configuration of hybrid passive filter for reactive power and harmonic compensation.

    Science.gov (United States)

    Kececioglu, O Fatih; Acikgoz, Hakan; Sekkeli, Mustafa

    2016-01-01

    Harmonics is one of the major power quality problems for power systems. The harmonics can be eliminated by power filters such as passive, active, and hybrid. In this study, a new passive filter configuration has been improved in addition to the existing passive filter configurations. Conventional hybrid passive filters are not successful to compensate rapidly changing reactive power demand. The proposed configure are capable of compensating both harmonics and reactive power at the same time. Simulation results show that performance of reactive power and harmonic compensation with advanced hybrid passive filter is better than conventional hybrid passive filters.

  1. Photovoltaic solar system connected to the electric power grid operating as active power generator and reactive power compensator

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, F.L.; Moraes, A.J.; Guimaraes, G.C.; Sanhueza, S.M.R.; Vaz, A.R. [Federal University of Uberlandia (UFU), MG (Brazil)

    2009-07-01

    In the case of photovoltaic solar systems (PV) acting as a distributed generation (DG), the DC energy obtained is fed through the power-conditioning unit (inverter) to the grid. The majority of contemporary inverters used in DG systems are current source inverters (CSI) operating at unity power factor. If, however, we assume that voltage source inverters (VSI) can be utilized instead of CSI, we can generate reactive power commensurate with the remaining unused capacity at any given point in time. According to the theory of instantaneous power, the reactive and active power of inverter can be regulated by changing the amplitude and the phase of the output voltage of the inverter. Based on this theory, the active power output and the reactive power compensation (RPC) of the system are realized simultaneously. When the insolation is weak or the PV modules are inoperative at night, the RPC feature of PV system can still be used to improve the utilization factor of the inverter. The MATLAB simulation results validate the feasibility of the method. (author)

  2. An OPF based approach for assessing the minimal reactive power support for generators in deregulated power systems

    International Nuclear Information System (INIS)

    Wu, H.; Yu, C.W.; Xu, N.; Lin, X.J.

    2008-01-01

    Reactive power support is an important ancillary service for secure and reliable operation in power markets. It has recently been recognized that the reactive power support for a generator has two components: one for supporting its own real power transmission and the other for supplying reactive demand, improving system security, and controlling system voltage; and that only the second part should receive financial compensation in competitive power markets. This makes the problem of separating these two components a new focus of current research. An OPF based reactive power optimization model along with a power flow tracing based method is proposed in this paper to tackle this problem. The methodology is tested on four test systems. Detailed analysis of the results of the 39-bus test system is reported. (author)

  3. Remuneration of the reactive power in the Argentinean supply market; Remuneracao da potencia reativa no mercado de suprimento argentino

    Energy Technology Data Exchange (ETDEWEB)

    Kerszberg, Ernesto M; Dravnovsky, Mario Carlos [Administradora del Mercado Mayorista Eletrico S.A. (Argentina)

    1996-05-01

    This work presents the standards and legislation about power reactive consumption by involved agents in the market electric power supply. It discusses how to remunerate this reactive and the compromises among the actors of the power electric system

  4. Reactivation of nuclear power plant construction projects. Plant status, policy issues and regulatory options

    International Nuclear Information System (INIS)

    Spangler, M.B.

    1986-07-01

    Prior to the TMI-2 accident on March 28, 1979, four nuclear power plant units that had previously been issued a construction permit were cancelled, principally because of reduced projections of regional power demand. Since that time, an additional 31 units with CPs have been cancelled and eight units deferred. On December 23, 1985 one of the deferred units (Limerick-2) was reactivated and construction resumed. The primary objective of this policy study is to identify the principal issues requiring office-level consideration in the event of reactivation of the construction of one or more of the nuclear power plants falling into two categories: (1) LWR units issued a construction permit whose construction has been cancelled, and (2) LWR units whose construction has been deferred. The study scope is limited to identifying regulatory issues or questions deserving analysis rather than providing, at this time, answers or recommended actions. Five tasks are addressed: a tabulation and discussion of the status of all cancelled and deferred LWR units; and identification of potential safety and environmental issues; an identification of regulatory or policy issues and needed information to determine the desirability of revising certain rules and policies; and identification of regulatory options and decision criteria; and an identification of decision considerations in determining staff requirements and organizational coordination of LWR reactivation policy and implementation efforts. 41 refs

  5. Active and reactive power control of a current-source PWM-rectifier using space vectors

    Energy Technology Data Exchange (ETDEWEB)

    Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics

    1997-12-31

    In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.

  6. Extended reactivity trace curves for nuclear power control with no power shooting

    International Nuclear Information System (INIS)

    Ratemi, W. M.; Elbuni, M. S.

    1995-01-01

    This paper introduces a new concept of reactivity trace curve (RTC) for nuclear power control with no power shooting. The concept is based on recent work of bernard et al. on the dynamic period of nuclear reactors. RTC-method is simulated for both a static effective decay constant corresponding to a one-group delayed neutrons model, and a dynamic effective decay constant corresponding to a six-group delayed neutrons model. A fitting to the RTC of a six-group reactor model resulted in a closed from formula for the RTC that couples the effect of both static and dynamic decay constants. Hence, introducing two 'fingerprints' for the reactor in concern to identify a closed from RTC formula capable of controlling the reactor power. Integration of the RTC with control rod integral curves results in the ρ-z-t diagram. This diagram relates the amount of recommended reactivity (RTC), the position of control rod, and the time required for power control. 8 figs

  7. Extended reactivity trace curves for nuclear power control with no power shooting

    Energy Technology Data Exchange (ETDEWEB)

    Ratemi, W M; Elbuni, M S [Faculty of engineering, Al Fateh universty Tripoli (Libyan Arab Jamahiriya)

    1995-10-01

    This paper introduces a new concept of reactivity trace curve (RTC) for nuclear power control with no power shooting. The concept is based on recent work of bernard et al. on the dynamic period of nuclear reactors. RTC-method is simulated for both a static effective decay constant corresponding to a one-group delayed neutrons model, and a dynamic effective decay constant corresponding to a six-group delayed neutrons model. A fitting to the RTC of a six-group reactor model resulted in a closed from formula for the RTC that couples the effect of both static and dynamic decay constants. Hence, introducing two `fingerprints` for the reactor in concern to identify a closed from RTC formula capable of controlling the reactor power. Integration of the RTC with control rod integral curves results in the {rho}-z-t diagram. This diagram relates the amount of recommended reactivity (RTC), the position of control rod, and the time required for power control. 8 figs.

  8. An accurate reactive power control study in virtual flux droop control

    Science.gov (United States)

    Wang, Aimeng; Zhang, Jia

    2017-12-01

    This paper investigates the problem of reactive power sharing based on virtual flux droop method. Firstly, flux droop control method is derived, where complicated multiple feedback loops and parameter regulation are avoided. Then, the reasons for inaccurate reactive power sharing are theoretically analyzed. Further, a novel reactive power control scheme is proposed which consists of three parts: compensation control, voltage recovery control and flux droop control. Finally, the proposed reactive power control strategy is verified in a simplified microgrid model with two parallel DGs. The simulation results show that the proposed control scheme can achieve accurate reactive power sharing and zero deviation of voltage. Meanwhile, it has some advantages of simple control and excellent dynamic and static performance.

  9. The Use of Nuclear Generation to Provide Power System Stability

    OpenAIRE

    Heather Wyman-Pain; Yuankai Bian; Furong Li

    2016-01-01

    The decreasing use of fossil fuel power stations has a negative effect on the stability of the electricity systems in many countries. Nuclear power stations have traditionally provided minimal ancillary services to support the system but this must change in the future as they replace fossil fuel generators. This paper explains the development of the four most popular reactor types still in regular operation across the world which have formed the basis for most reactor dev...

  10. An Improved Droop Control Strategy for Reactive Power Sharing in Islanded Microgrid

    DEFF Research Database (Denmark)

    Han, Hua; Liu, Yao; Sun, Yao

    2015-01-01

    For microgrid in islanded operation, due to the effects of mismatched line impedance, the reactive power could not be shared accurately with the conventional droop method. To improve the reactive power sharing accuracy, this paper proposes an improved droop control method. The proposed method...... in output voltage amplitude. Therefore, the voltage recovery operation is proposed to compensate the decrease. The needed communication in this method is very simple, and the plug-and-play is reserved. Simulations and experimental results show that the improved droop controller can share load active...... and reactive power, improve the power quality of the microgrid, and also have a good dynamic performance....

  11. Framework for the analysis of reactive power dispatch in energy pools

    International Nuclear Information System (INIS)

    Salgado, R.S.; Irving, M.R.

    2004-01-01

    This paper proposes a framework for the simulation and analysis of the reactive power distribution in electric energy markets of the pool type. Firstly, the analytical formulation of the OPF problem, with three optional performance indexes for the reactive power dispatch, is discussed. These OPF objectives are used to determine the reactive power distribution for a given active power dispatch (obtained through merit-order strategy, for instance). An allocation strategy is used to assess the participation of each power system agent in the loss/reactive power distribution. This strategy uses the premise of co-operative game theory. Numerical results obtained with the Ward-Hale 6-bus test system illustrate the main aspects of the proposed methodology. (author)

  12. Strategies for reactive power control in wind farms with STATCOM

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Gonzalez, Francisco [Catalonia Institute for Energy Research (IREC), Barcelona (Spain); Martinez-Rojas, Marcela [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Barcelona (Spain). Dept. d' Enginyeria Electrica; Sumper, Andreas; Gomis-Bellmunt, Oriol [Catalonia Institute for Energy Research (IREC), Barcelona (Spain); Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Barcelona (Spain). Dept. d' Enginyeria Electrica

    2010-07-01

    This paper presents two strategies for reactive current control in wind farms with STATCOM under fault ride-through (FRT) situations. First, the technical requirements of the Spanish and German grid codes related to the reactive current under FRT situations are presented. Second, STATCOM and its control system are introduced. Third, the modeling done of the wind farm, the STATCOM, and the network are presented. Finally, control strategies for reactive current delivered by the park to the network under FRT situations are shown. The result of the implementation of each control strategy is shown by simulation. (orig.)

  13. Combination of AC Transmission Expansion Planning and Reactive Power Planning in the restructured power system

    International Nuclear Information System (INIS)

    Hooshmand, Rahmat-Allah; Hemmati, Reza; Parastegari, Moein

    2012-01-01

    Highlights: ► To overcome the disadvantages of DC model in Transmission Expansion Planning, AC model should be used. ► The Transmission Expansion Planning associated with Reactive Power Planning results in fewer new transmission lines. ► Electricity market concepts should be considered in Transmission Expansion Planning problem. ► Reliability aspects should be considered in Transmission Expansion Planning problem. ► Particle Swarm Optimization is a suitable optimization method to solve Transmission Expansion Planning problem. - Abstract: Transmission Expansion Planning (TEP) is an important issue in power system studies. It involves decisions on location and number of new transmission lines. Before deregulation of the power system, the goal of TEP problem was investment cost minimization. But in the restructured power system, nodal prices, congestion management, congestion surplus and so on, have been considered too. In this paper, an AC model of TEP problem (AC-TEP) associated with Reactive Power Planning (RPP) is presented. The goals of the proposed planning problem are to minimize investment cost and maximize social benefit at the same time. In the proposed planning problem, in order to improve the reliability of the system the Expected Energy Not Supplied (EENS) index of the system is limited by a constraint. For this purpose, Monte Carlo simulation method is used to determine the EENS. Particle Swarm Optimization (PSO) method is used to solve the proposed planning problem which is a nonlinear mixed integer optimization problem. Simulation results on Garver and RTS systems verify the effectiveness of the proposed planning problem for reduction of the total investment cost, EENS index and also increasing social welfare of the system.

  14. Comprehensive Reactive Power Support of DFIG Adapted to Different Depth of Voltage Sags

    Directory of Open Access Journals (Sweden)

    Yangwu Shen

    2017-06-01

    Full Text Available The low voltage ride-through (LVRT capability of the doubly-fed induction generator (DFIG significantly impacts upon the integration of wind power into the power grid. This paper develops a novel comprehensive control strategy to enhance the LVRT and reactive power support capacities of the DFIG by installing the energy storage system (ESS. The ESS is connected to the DC-link capacitor of the DFIG and used to regulate the DC-link voltage during normal or fault operations. The unbalanced power between the captured wind power and the power injected to the grid during the transient process is absorbed or compensated by the ESS. The rotor-side converter (RSC is used to control the maximum power production and the grid-side converter (GSC is used to control the reactive power before participating in the voltage support. When the supply voltage continues to drop, the rotor speed is increased by controlling the RSC to realize the LVRT capability and help the GSC further enhance the reactive power support capability. The capacity of the GSC is dedicated to injecting the reactive power to the grid. An auxiliary transient pitch angle controller is proposed to protect the generator’s over speed. Both RSC and GSC act as reactive power sources to further enhance the voltage support capability with serious voltage sags. Simulations based on a single-machine infinite-bus power system verify the effectiveness of the developed comprehensive control strategy.

  15. Measurements of the Reactivity Properties of the Aagesta Nuclear Power Reactor at Zero Power

    Energy Technology Data Exchange (ETDEWEB)

    Bernander, G

    1967-07-15

    The moderator level and temperature coefficients of reactivity and control rod differential reactivity worths have been determined at zero power by means of period measurements. The moderator level coefficient and the corresponding critical level have been measured for the 32, 68 and 136 fuel assembly cores at room temperature for cores with and without control rods. From these results the worths of control rods have been derived. HETERO calculations give up to 15 % lower values than the experimental results. The cold fresh core has an excess reactivity of 9.0 {+-} 0.2 %. The temperature coefficient and differential control rod worths were measured for the fully loaded core with filled tank in the temperature range between 30 and 210 deg C. Critical positions as a function of temperature were obtained for the corresponding control rod groups. No relevant calculations of the temperature coefficient for comparison with the experimental values have yet been made, but the experimental results together with measured critical control rod positions give good opportunities to check calculational programs. HETERO has been shown in these cases to reproduce differential control rod worths and critical positions fairly well. However, a certain underestimation of the rod effectiveness is quite noticeable. The relative increase in control rod effectiveness with a temperature change from 20 to 220 deg C has been estimated to be 0.29 {+-} 0.06.

  16. An Optimal Reactive Power Control Strategy for a DFIG-Based Wind Farm to Damp the Sub-Synchronous Oscillation of a Power System

    Directory of Open Access Journals (Sweden)

    Bin Zhao

    2014-05-01

    Full Text Available This study presents the auxiliary damping control with the reactive power loop on the rotor-side converter of doubly-fed induction generator (DFIG-based wind farms to depress the sub-synchronous resonance oscillations in nearby turbogenerators. These generators are connected to a series capacitive compensation transmission system. First, the damping effect of the reactive power control of the DFIG-based wind farms was theoretically analyzed, and a transfer function between turbogenerator speed and the output reactive power of the wind farms was introduced to derive the analytical expression of the damping coefficient. The phase range to obtain positive damping was determined. Second, the PID phase compensation parameters of the auxiliary damping controller were optimized by a genetic algorithm to obtain the optimum damping in the entire subsynchronous frequency band. Finally, the validity and effectiveness of the proposed auxiliary damping control were demonstrated on a modified version of the IEEE first benchmark model by time domain simulation analysis with the use of DigSILENT/PowerFactory. Theoretical analysis and simulation results show that this derived damping factor expression and the condition of the positive damping can effectively analyze their impact on the system sub-synchronous oscillations, the proposed wind farms reactive power additional damping control strategy can provide the optimal damping effect over the whole sub-synchronous frequency band, and the control effect is better than the active power additional damping control strategy based on the power system stabilizator.

  17. Multi-objective Reactive Power Optimization Based on Improved Particle Swarm Algorithm

    Science.gov (United States)

    Cui, Xue; Gao, Jian; Feng, Yunbin; Zou, Chenlu; Liu, Huanlei

    2018-01-01

    In this paper, an optimization model with the minimum active power loss and minimum voltage deviation of node and maximum static voltage stability margin as the optimization objective is proposed for the reactive power optimization problems. By defining the index value of reactive power compensation, the optimal reactive power compensation node was selected. The particle swarm optimization algorithm was improved, and the selection pool of global optimal and the global optimal of probability (p-gbest) were introduced. A set of Pareto optimal solution sets is obtained by this algorithm. And by calculating the fuzzy membership value of the pareto optimal solution sets, individuals with the smallest fuzzy membership value were selected as the final optimization results. The above improved algorithm is used to optimize the reactive power of IEEE14 standard node system. Through the comparison and analysis of the results, it has been proven that the optimization effect of this algorithm was very good.

  18. Multiagent-Based Reactive Power Sharing and Control Model for Islanded Microgrids

    DEFF Research Database (Denmark)

    Chen, Feixiong; Chen, Minyou; Li, Qiang

    2016-01-01

    of the control model, in which the uncertainty of intermittent DGs, variations in load demands, as well as impacts of time delays are considered. The simulation results demonstrate the eectiveness of the control model in proportional reactive power sharing, and the plug and play capability of the control model......In islanded microgrids (MGs), the reactive power cannot be shared proportionally among distributed generators (DGs) with conventional droop control, due to the mismatch in feeder impedances. For the purpose of proportional reactive power sharing, a multiagent system (MAS) based distributed control...

  19. Real-Time Reactive Power Distribution in Microgrids by Dynamic Programing

    DEFF Research Database (Denmark)

    Levron, Yoash; Beck, Yuval; Katzir, Liran

    2017-01-01

    In this paper a new real-time optimization method for reactive power distribution in microgrids is proposed. The method enables location of a globally optimal distribution of reactive power under normal operating conditions. The method exploits the typical compact structure of microgrids to obtain...... combination of reactive powers, by means of dynamic programming. Since every single step involves a one-dimensional problem, the complexity of the solution is only linear with the number of clusters, and as a result, a globally optimal solution may be obtained in real time. The paper includes the results...

  20. Distributed Reactive Power Control based Conservation Voltage Reduction in Active Distribution Systems

    Directory of Open Access Journals (Sweden)

    EMIROGLU, S.

    2017-11-01

    Full Text Available This paper proposes a distributed reactive power control based approach to deploy Volt/VAr optimization (VVO / Conservation Voltage Reduction (CVR algorithm in a distribution network with distributed generations (DG units and distribution static synchronous compensators (D-STATCOM. A three-phase VVO/CVR problem is formulated and the reactive power references of D-STATCOMs and DGs are determined in a distributed way by decomposing the VVO/CVR problem into voltage and reactive power control. The main purpose is to determine the coordination between voltage regulator (VR and reactive power sources (Capacitors, D-STATCOMs and DGs based on VVO/CVR. The study shows that the reactive power injection capability of DG units may play an important role in VVO/CVR. In addition, it is shown that the coordination of VR and reactive power sources does not only save more energy and power but also reduces the power losses. Moreover, the proposed VVO/CVR algorithm reduces the computational burden and finds fast solutions. To illustrate the effectiveness of the proposed method, the VVO/CVR is performed on the IEEE 13-node test system feeder considering unbalanced loading and line configurations. The tests are performed taking the practical voltage-dependent load modeling and different customer types into consideration to improve accuracy.

  1. Review of Active and Reactive Power Sharing Strategies in Hierarchical Controlled Microgrids

    DEFF Research Database (Denmark)

    Han, Yang; Li, Hong; Shen, Pan

    2017-01-01

    Microgrids consist of multiple parallel-connected distributed generation (DG) units with coordinated control strategies, which are able to operate in both grid-connected and islanded mode. Microgrids are attracting more and more attention since they can alleviate the stress of main transmission...... systems, reduce feeder losses, and improve system power quality. When the islanded microgrids are concerned, it is important to maintain system stability and achieve load power sharing among the multiple parallel-connected DG units. However, the poor active and reactive power sharing problems due...... in this paper for active power sharing. Moreover, nonlinear and unbalanced loads could further affect the reactive power sharing when regulating the active power, and it is difficult to share the reactive power accurately only by using the enhanced virtual impedance method. Therefore, the hierarchical control...

  2. Optimization of a Virtual Power Plant to Provide Frequency Support.

    Energy Technology Data Exchange (ETDEWEB)

    Neely, Jason C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gonzalez, Sigifredo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lave, Matthew Samuel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Delhotal, Jarod James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    Increasing the penetration of distributed renewable sources, including photovoltaic (PV) sources, poses technical challenges for grid management. The grid has been optimized over decades to rely upon large centralized power plants with well-established feedback controls, but now non-dispatchable, renewable sources are displacing these controllable generators. This one-year study was funded by the Department of Energy (DOE) SunShot program and is intended to better utilize those variable resources by providing electric utilities with the tools to implement frequency regulation and primary frequency reserves using aggregated renewable resources, known as a virtual power plant. The goal is to eventually enable the integration of 100s of Gigawatts into US power systems.

  3. Improvement of the dynamic response of the ITER Reactive Power Compensation system

    International Nuclear Information System (INIS)

    Finotti, Claudio; Gaio, Elena; Song, Inho; Tao, Jun; Benfatto, Ivone

    2015-01-01

    Highlights: • The slow response reasons of the classic ITER Reactive Power Compensation (RPC) control are explained. • The dynamic behaviors of the ac/dc converter and of the RPC are characterized. • New control concept to speed up the RPC response is developed. • Good performance of the new RPC control is verified even during fast transient conditions. - Abstract: The ITER ac/dc conversion system can absorb a total active and reactive power up to 500 MW and 950 Mvar, respectively. The Reactive Power Compensation (RPC) system is rated for a nominal power of 750 Mvar necessary to comply with the allowable reactive power limit value from the grid of 200 Mvar. This system is currently under construction and is based on Static Var Compensation technology with Thyristor Controlled Reactor (TCR) and Tuned Filters. The RPC has to minimize the demand of reactive power from the grid; its control is based on a feed-forward method, where the corrective input is the measurement of the reactive power consumption of the ac/dc converters, derived from the 50 Hz component of the Fast Fourier Transform (FFT) of the three-phase voltages and currents. The delay introduced by the FFT calculation and the slow response of the TCR could make the response speed of the RPC not sufficient to face fast variations of the reactive power demand and therefore in this paper a new controller of the RPC able to overcome this shortcoming is proposed and evaluated. It is based on the calculation of the predicted consumption of the reactive power by using the voltage reference signals coming from the Plasma Control System and the measurements of the dc current of the ac/dc converters and of the 66 kV busbar voltage, and on the speed up of the RPC control by introducing a lead–lag transfer function.

  4. Improvement of the dynamic response of the ITER Reactive Power Compensation system

    Energy Technology Data Exchange (ETDEWEB)

    Finotti, Claudio, E-mail: claudio.finotti@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Gaio, Elena [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Song, Inho; Tao, Jun; Benfatto, Ivone [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2015-10-15

    Highlights: • The slow response reasons of the classic ITER Reactive Power Compensation (RPC) control are explained. • The dynamic behaviors of the ac/dc converter and of the RPC are characterized. • New control concept to speed up the RPC response is developed. • Good performance of the new RPC control is verified even during fast transient conditions. - Abstract: The ITER ac/dc conversion system can absorb a total active and reactive power up to 500 MW and 950 Mvar, respectively. The Reactive Power Compensation (RPC) system is rated for a nominal power of 750 Mvar necessary to comply with the allowable reactive power limit value from the grid of 200 Mvar. This system is currently under construction and is based on Static Var Compensation technology with Thyristor Controlled Reactor (TCR) and Tuned Filters. The RPC has to minimize the demand of reactive power from the grid; its control is based on a feed-forward method, where the corrective input is the measurement of the reactive power consumption of the ac/dc converters, derived from the 50 Hz component of the Fast Fourier Transform (FFT) of the three-phase voltages and currents. The delay introduced by the FFT calculation and the slow response of the TCR could make the response speed of the RPC not sufficient to face fast variations of the reactive power demand and therefore in this paper a new controller of the RPC able to overcome this shortcoming is proposed and evaluated. It is based on the calculation of the predicted consumption of the reactive power by using the voltage reference signals coming from the Plasma Control System and the measurements of the dc current of the ac/dc converters and of the 66 kV busbar voltage, and on the speed up of the RPC control by introducing a lead–lag transfer function.

  5. Biodiesel by catalytic reactive distillation powered by metal oxides

    NARCIS (Netherlands)

    Kiss, A.A.; Dimian, A.C.; Rothenberg, G.

    2008-01-01

    The properties and use of biodiesel as a renewable fuel as well as the problems associated with its current production processes are outlined. A novel sustainable esterification process based on catalytic reactive distillation is proposed. The pros and cons of manufacturing biodiesel via fatty acid

  6. A Hierarchical Control Scheme for Reactive Power and Harmonic Current Sharing in Islanded Microgrids

    DEFF Research Database (Denmark)

    Lorzadeh, Iman; Firoozabadi, Mehdi Savaghebi; Askarian Abyaneh, Hossein

    2015-01-01

    In this paper, a hierarchical control scheme consisting of primary and secondary levels is proposed for achieving accurate reactive power and harmonic currents sharing among interface inverters of distributed generators (DGs) in islanded microgrids. Firstly, fundamental and main harmonic componen...

  7. Estimation of reactive power sources dynamic limits for Volt / VAr control

    International Nuclear Information System (INIS)

    Orozco Alvarado, Juan Jose

    2013-01-01

    A generic model of capacity curves is obtained from the theoretical capacity curves of the distribution generators and reactive compensation elements. The obtained generic model is structured in a simplified method of points, taking eight strategic points of two detailed curves of a generator and through a series of interpolations, achieving the estimation of limits of capacity of delivery / consumption of the generator. The theory of electric generation elements and reactive power compensation is reviewed. The curves of capacity 'Reactive Power / Active Power' are achieved for different values of tension: from wind generators with complete converter and doubly fed, photovoltaic generators with inverter and synchronous generators. The 'Reactive Power / Line Tension' capacity curves are acquired from static var compensators (SVC). The generic limits of generators and SVC are estimated from the capacity curves [es

  8. Review of reactive power dispatch strategies for loss minimization in a DFIG-based wind farm

    DEFF Research Database (Denmark)

    Zhang, Baohua; Hu, Weihao; Hou, Peng

    2017-01-01

    power control strategies are investigated. All of the combined strategies are formulated based on the comprehensive loss models of WFs, including the loss models of DFIGs, converters, filters, transformers, and cables of the collection system. Optimization problems are solved by a Modified Particle......This paper reviews and compares the performance of reactive power dispatch strategies for the loss minimization of Doubly Fed Induction Generator (DFIG)-based Wind Farms (WFs). Twelve possible combinations of three WF level reactive power dispatch strategies and fourWind Turbine (WT) level reactive...... Swarm Optimization (MPSO) algorithm. The effectiveness of these strategies is evaluated by simulations on a carefully designed WF under a series of cases with different wind speeds and reactive power requirements of the WF. The wind speed at each WT inside the WF is calculated using the Jensen wake...

  9. Reactive power balance in a distribution network with wind farms and CHPS

    DEFF Research Database (Denmark)

    Lund, Torsten; Nielsen, John Eli; Hylle, Per

    2007-01-01

    In Denmark, a large part of the electricity is generated by wind turbines and combined heat and power plants. Most of them are connected to the distribution systems. In periods with high wind speeds, large flows of reactive power have been observed between the 150kV and the 60 kV systems. The tra......In Denmark, a large part of the electricity is generated by wind turbines and combined heat and power plants. Most of them are connected to the distribution systems. In periods with high wind speeds, large flows of reactive power have been observed between the 150kV and the 60 kV systems....... The transfer of reactive power reduces the capacity of the lines, causes thermal losses and can in some cases reduce the voltage stability margin of the system. To identify the origin of the problem, an actual distribution system with a high penetration of wind power and distributed generation has been...

  10. Local Reactive Power Control Methods for Overvoltage Prevention of Distributed Solar Inverters in Low-Voltage Grids

    DEFF Research Database (Denmark)

    Demirok, Erhan; Gonzalez, Pablo Casado; Frederiksen, Kenn H. B.

    2011-01-01

    on sensitivity analysis. The sensitivity analysis shows that the same amount of reactive power becomes more effective for grid voltage support if the solar inverter is located at the end of a feeder. Based on this fundamental knowledge, a location-dependent power factor set value can be assigned to each inverter......voltage (LV) grids by means of solar inverters with reactive power control capability. This paper underlines weak points of standard reactive power strategies which are already imposed by certain grid codes, and then, the study introduces a new reactive power control method that is based......, and the grid voltage support can be achieved with less total reactive power consumption. In order to prevent unnecessary reactive power absorption from the grid during admissible voltage range or to increase reactive power contribution from the inverters that are closest to the transformer during grid...

  11. A heuristic technique to determine corrective control actions for reactive power flows

    Energy Technology Data Exchange (ETDEWEB)

    Trigo, Angel L.; Martinez, Jose L.; Riquelme, Jesus; Romero, Esther [Department of Electrical Engineering, University of Sevilla (Spain)

    2011-01-15

    This paper presents a sensitivity-based heuristic tool designed to help the system operator in the reactive power flow control problem. The objective of the proposed technique is to determine control actions to ensure that reactive power flows in transmission-subtransmission boundary transformers remain within specified limits, satisfying the new regulatory constraints imposed in most of deregulated markets. With this new constraint the utilities want to guarantee that the utility is able to satisfy its own reactive power requirements, avoiding reactive power flows through long distances in order to reduce the well known disadvantages that reactive power circulation has in the system. A 5-bus tutorial system is used to present the proposed algorithm. The results of the application of the proposed technique to the IEEE 118 buses system and to a regional subtransmission network of the South of Spain are reported and analyzed. In this last actual case, the aim is to maintain reactive power flows in transmission/distribution transformers between those limits set by the Spanish Regulation. A comparison between the proposed tool and a conventional OPF is discussed. (author)

  12. Consensus-based Distributed Control for Accurate Reactive, Harmonic and Imbalance Power Sharing in Microgrids

    DEFF Research Database (Denmark)

    Zhou, Jianguo; Kim, Sunghyok; Zhang, Huaguang

    2018-01-01

    This paper investigates the issue of accurate reactive, harmonic and imbalance power sharing in a microgrid. Harmonic and imbalance droop controllers are developed to proportionally share the harmonic power and the imbalance power among distributed generation (DG) units and improve the voltage...... voltage. With the proposed methods, the microgrid system reliability and flexibility can be enhanced and the knowledge of the line impedance is not required. And the reactive, harmonic and imbalance power can be proportionally shared among the DG units. Moreover, the quality of the voltage at PCC can...

  13. Subcritical reactivity measurement at Angra 1 nuclear power plant

    International Nuclear Information System (INIS)

    Kuramoto, Renato Yoichi Ribeiro; Miranda, Anselmo Ferreira

    2011-01-01

    In order to speed up the Angra 1 NPP physics tests, this work intends to develop a digital reactivity meter combined with a methodology of the modified Neutron Source Multiplication (NSM) method with correction factors for subcriticality measurements at Angra 1 NPP. In the first part of this work, we have applied the Modified Neutron Source Multiplication (MNSM) Method with fundamental mode extraction, in order to improve the monitoring of the subcriticality at Angra 1 NPP during the criticality approach. In the second part, we developed a preliminary subcritical reactivity meter algorithm based on the point-reactor inverse kinetic model with six delayed neutron groups and external neutron source. The source strength was obtained through the Least Squares Inverse Kinetics Method (LSIKM). (author)

  14. Simulation and study on reactivity disturbs dynamic character of HTR-10 nuclear power system

    International Nuclear Information System (INIS)

    Huang Xiaojin; Feng Yuankun

    2002-01-01

    In order to not only know 10 MW High Temperature Gas Cooled Reactor (HTR-10) nuclear power system's dynamic character more deeply but also to satisfy requirements of control system's design and analysis, the dynamic model of HTR-10 nuclear power system is established on the basis of dynamic model of HTR-10 nuclear system, which supplies turbine and generate electricity system model. Using this model, system's main variables' dynamic processes are simulated when control rod takes step reactivity disturb. The concussive progresses which is caused by reactivity disturb are analyzed. The results indicate that fuel temperature changing more slowly than nuclear power makes reactivity negative feedback not to restrain power changing, and then power concussive progress comes to being

  15. A Method of Dynamic Extended Reactive Power Optimization in Distribution Network Containing Photovoltaic-Storage System

    Science.gov (United States)

    Wang, Wu; Huang, Wei; Zhang, Yongjun

    2018-03-01

    The grid-integration of Photovoltaic-Storage System brings some undefined factors to the network. In order to make full use of the adjusting ability of Photovoltaic-Storage System (PSS), this paper puts forward a reactive power optimization model, which are used to construct the objective function based on power loss and the device adjusting cost, including energy storage adjusting cost. By using Cataclysmic Genetic Algorithm to solve this optimization problem, and comparing with other optimization method, the result proved that: the method of dynamic extended reactive power optimization this article puts forward, can enhance the effect of reactive power optimization, including reducing power loss and device adjusting cost, meanwhile, it gives consideration to the safety of voltage.

  16. Coordinated Reactive Power and Voltage Management for Offshore Wind Farms with AC-connection

    DEFF Research Database (Denmark)

    Heussen, Kai

    2008-01-01

    This paper analyzes voltage and reactive power in a wind farm in dependence on switchable shunt and tap-changer settings in connection with the control ranges of flexible reactive power sources. Attention is paid to their interdependent effects on central control variables, such as voltage...... in the collection grid, reactive power exported to the grid and internal active power losses. An aggregated steady-state model of an offshore wind farm is presented and a reduced mathematical representation suitable for symbolic analysis is developed. A coordination scheme is proposed to coordinate fast continuous...... control inputs with slow tap-changing devices using a short-term prediction. The proposed scheme is aimed at balancing cost factors such as wear of switching components, active power loss within the wind farm and STATCOM capacity....

  17. A New Approach to Optimal Allocation of Reactive Power Ancillary Service in Distribution Systems in the Presence of Distributed Energy Resources

    Directory of Open Access Journals (Sweden)

    Abouzar Samimi

    2015-11-01

    Full Text Available One of the most important Distribution System Operators (DSO schemes addresses the Volt/Var control (VVC problem. Developing a cost-based reactive power dispatch model for distribution systems, in which the reactive powers are appropriately priced, can motivate Distributed Energy Resources (DERs to participate actively in VVC. In this paper, new reactive power cost models for DERs, including synchronous machine-based DGs and wind turbines (WTs, are formulated based on their capability curves. To address VVC in the context of competitive electricity markets in distribution systems, first, in a day-ahead active power market, the initial active power dispatch of generation units is estimated considering environmental and economic aspects. Based on the results of the initial active power dispatch, the proposed VVC model is executed to optimally allocate reactive power support among all providers. Another novelty of this paper lies in the pricing scheme that rewards transformers and capacitors for tap and step changing, respectively, while incorporating the reactive power dispatch model. A Benders decomposition algorithm is employed as a solution method to solve the proposed reactive power dispatch, which is a mixed integer non-linear programming (MINLP problem. Finally, a typical 22-bus distribution network is used to verify the efficiency of the proposed method.

  18. ACCOUNTING OF REACTIVE POWER COMPENSATION LEVEL AT PAYMENT CALCULATION OF TECHNOLOGICAL CONSUMPTION (LOSSES OF ELECTRIC POWER FOR ITS TRANSMISSION IN POWER NETWORK

    Directory of Open Access Journals (Sweden)

    E. P. Zabello

    2005-01-01

    Full Text Available The method is proposed to make a correction in payment for consumption of reactive energy and power which is attributed to deviation of actual activation energy losses for reactive power compensation from their standard value. It is recommended to calculate standard loss values for every voltage level and actual loss values are to be determined with the help of application of remote electronic accounting means in the current mode of power consumption.

  19. Study for reactive power on distribution system line B RSG-GAS

    International Nuclear Information System (INIS)

    Yan Bony Marsahala

    2010-01-01

    Study for reactive power on distribution system line B RSG-GA is already done. The study intended to evaluate how much inductive load need the reactive power (positive), how much power factor, and what will be done to increase the power factor. The reactive power is the losses power, can't be changed into energy, but it is need for transmission process and it is cause the energy losses. The loads on distribution system line B consist of induction motors which are used for primary cooling system and secondary cooling system, lift, blower on cooling tower, and air condition system. Due to the motors using, the power factor are falling down to low. By the calculation results give that the inductive loads on distribution line B are 850 KVA and these loads caused the low power factor 0.80. If we want to increase the power factor up to 0.95, it is need to install the reactive loads likes capacitor bank 250 KVAR. (author)

  20. Mitigating Space Weather Impacts on the Power Grid in Real-Time: Applying 3-D EarthScope Magnetotelluric Data to Forecasting Reactive Power Loss in Power Transformers

    Science.gov (United States)

    Schultz, A.; Bonner, L. R., IV

    2017-12-01

    Current efforts to assess risk to the power grid from geomagnetic disturbances (GMDs) that result in geomagnetically induced currents (GICs) seek to identify potential "hotspots," based on statistical models of GMD storm scenarios and power distribution grounding models that assume that the electrical conductivity of the Earth's crust and mantle varies only with depth. The NSF-supported EarthScope Magnetotelluric (MT) Program operated by Oregon State University has mapped 3-D ground electrical conductivity structure across more than half of the continental US. MT data, the naturally occurring time variations in the Earth's vector electric and magnetic fields at ground level, are used to determine the MT impedance tensor for each site (the ratio of horizontal vector electric and magnetic fields at ground level expressed as a complex-valued frequency domain quantity). The impedance provides information on the 3-D electrical conductivity structure of the Earth's crust and mantle. We demonstrate that use of 3-D ground conductivity information significantly improves the fidelity of GIC predictions over existing 1-D approaches. We project real-time magnetic field data streams from US Geological Survey magnetic observatories into a set of linear filters that employ the impedance data and that generate estimates of ground level electric fields at the locations of MT stations. The resulting ground electric fields are projected to and integrated along the path of power transmission lines. This serves as inputs to power flow models that represent the power transmission grid, yielding a time-varying set of quasi-real-time estimates of reactive power loss at the power transformers that are critical infrastructure for power distribution. We demonstrate that peak reactive power loss and hence peak risk for transformer damage from GICs does not necessarily occur during peak GMD storm times, but rather depends on the time-evolution of the polarization of the GMD's inducing fields

  1. Towards a Reactive Power Oscillation Damping Controller for Wind Power Plant Based on Full Converter Wind Turbines

    DEFF Research Database (Denmark)

    Knüppel, Thyge; Kumar, Sathess; Thuring, Patrik

    2012-01-01

    In this paper a power oscillation damping controller (POD) based on modulation of reactive power (Q POD) is analyzed where the modular and distributed characteristics of the wind power plant (WPP) are considered. For a Q POD it is essential that the phase of the modulated output is tightly...... contributes to a collective response. This ability is shown with a 150 wind turbine (WT) WPP with all WTs represented, and it is demonstrated that the WPP contributes to the inter-area damping. The work is based on a nonlinear, dynamic model of the 3.6 MW Siemens Wind Power WT....... controlled to achieve a positive damping contribution. It is investigated how a park level voltage, reactive power, and power factor control at different grid strengths interact with the Q POD in terms of a resulting phase shift. A WPP is modular and distributed and a WPP Q POD necessitate that each WT...

  2. Insurer Market Power Lowers Prices In Numerous Concentrated Provider Markets.

    Science.gov (United States)

    Scheffler, Richard M; Arnold, Daniel R

    2017-09-01

    Using prices of hospital admissions and visits to five types of physicians, we analyzed how provider and insurer market concentration-as measured by the Herfindahl-Hirschman Index (HHI)-interact and are correlated with prices. We found evidence that in the range of the Department of Justice's and Federal Trade Commission's definition of a moderately concentrated market (HHI of 1,500-2,500), insurers have the bargaining power to reduce provider prices in highly concentrated provider markets. In particular, hospital admission prices were 5 percent lower and cardiologist, radiologist, and hematologist/oncologist visit prices were 4 percent, 7 percent, and 19 percent lower, respectively, in markets with high provider concentration and insurer HHI above 2,000, compared to such markets with insurer HHI below 2,000. We did not find evidence that high insurer concentration reduced visit prices for primary care physicians or orthopedists, however. The policy dilemma that arises from our findings is that there are no insurer market mechanisms that will pass a portion of these price reductions on to consumers in the form of lower premiums. Large purchasers of health insurance such as state and federal governments, as well as the use of regulatory approaches, could provide a solution. Project HOPE—The People-to-People Health Foundation, Inc.

  3. The effect of reactive emotions expressed in response to another's anger on inferences of social power.

    Science.gov (United States)

    Hareli, Shlomo; David, Shlomo

    2017-06-01

    Social perception of emotions is influenced by the context in which it occurs. One such context is a social interaction involving an exchange of emotions. The way parties to the interaction are perceived is shaped by the combination of emotions exchanged. This idea was examined by assessing the extent to which expressions of anger toward a target-which, in isolation, are perceived as signals of high social power-are influenced by the target's emotional reaction to it (i.e., reactive emotions). Three studies show that the angry person was perceived as having a higher level of social power when this anger was responded by fear or sadness than when it was responded by neutrality or anger. Study 1 indicated that reactive emotions have a stronger effect on perceived social power when emotions were incongruent with gender stereotypes. Study 2 indicated that these effects are a result of these emotions serving as reactive emotions rather than a benchmark against which the angry person's power is assessed. Study 3 showed that reactive emotions affect perceived social power by serving as signals of the level to which the high social power suggested by the first person's expression is confirmed by its target. Comparing effects of reactive emotions to anger with reactive emotions to sadness, showed that perceived social power of the expresser is determined by the nature of the expression, with some adjustment caused by the reactive emotions. This underscores the importance of social interaction as a context for the social perception of emotions. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  4. Reactive power compensation. System service - line quality. 2. ed.; Blindleistungskompensation. Systemdienstleistung - Netzqualitaet

    Energy Technology Data Exchange (ETDEWEB)

    Grosse-Gehling, Martin; Just, Wolfgang; Reese, Juergen; Schlabbach, Juergen

    2013-11-01

    Reactive power compensation is playing an increasingly important role as the need for an efficient use of operating equipment and power grids continues to grow. This book presents the fundamentals of reactive power compensation in low and medium voltage grids, offering a wealth of application and calculation examples that will further the reader's understanding of the following topics: 1. design, dimensioning and operation of capacitors and capacitor installations; 2. long-term stability and ageing of capacitor installations; 3. use of passive and active filters; 4. improvement of voltage quality by means of filters and capacitor installations; 5. provision of reactive power compensation by means of power electronics; 6. costs and economic efficiency of reactive power compensation and filter equipment; 7. considerations from the viewpoint of the power supply industry; price regulations; 8. information requirements concerning PCB-containing capacitors; 9. climate protection and energy efficiency through reactive power compensation; 10. technical connection requirements and guidelines; 11. special technical issues concerning the use of reactive power compensation installations. [German] Die Blindleistungskompensation gewinnt angesichts der Notwendigkeit zur erhoehten Ausnutzung der Betriebsmittel und Netze zunehmend an Bedeutung. In diesem Buch werden die Grundlagen der Blindleistungskompensation in Nieder- und Mittelspannungsnetzen beschrieben und folgende Themen anhand zahlreicher Anwendungs- und Berechnungsbeispiele vertieft: 1. Aufbau, Auslegung und Betrieb von Kondensatoren und Kondensatoranlagen, 2. Langzeitstabilitaet und Alterung von Kondensatoranlagen, 3. Einsatz passiver und aktiver Filter, 4. Verbesserung der Spannungsqualitaet durch Filter und Kondensatoranlagen, 5. Blindleistungsbereitstellung mit Leistungselektronik, 6. Kosten und Wirtschaftlichkeit von Kompensations- und Filteranlagen, 7. Elektrizitaetswirtschaftliche Betrachtungen

  5. Preliminary study on the reactivation of the WERAP small hydro power station in Bubikon

    International Nuclear Information System (INIS)

    Bretscher, A.; Gutzwiller, S.

    2003-01-01

    This study on the revitalisation of a small hydro power station belonging to old spinning mill in Bubikon, Switzerland, proposes ideas for the reactivation of an old hydropower installation that once helped power a spinning mill. Details are given on the history of the mill and the hydrological conditions to be expected at the site. Three variants are proposed for the refurbishment, including the revision of the power station's existing 44 kW Francis turbine dating from 1908, the addition of further, similar Francis turbine or its replacement with a new 61 kW Francis turbine. The costs and amortisation of the refurbishment variants are examined, the revenues that can be expected from its operation and other financial factors are discussed. Further, environmental and legal aspects of the project are examined and suggestions are made for the next steps to be taken towards the realisation of this small hydropower plant. An annex provides photographs of the location and the power station's equipment

  6. Positional differences in reactive hyperemia provide insight into initial phase of exercise hyperemia

    OpenAIRE

    Jasperse, Jeffrey L.; Shoemaker, J. Kevin; Gray, Eric J.; Clifford, Philip S.

    2015-01-01

    Studies have reported a greater blood flow response to muscle contractions when the limb is below the heart compared with above the heart, and these results have been interpreted as evidence for a skeletal muscle pump contribution to exercise hyperemia. If limb position affects the blood flow response to other vascular challenges such as reactive hyperemia, this interpretation may not be correct. We hypothesized that the magnitude of reactive hyperemia would be greater with the limb below the...

  7. Distribution factors for reactive power in the presence of bilateral transactions

    International Nuclear Information System (INIS)

    De Tuglie, E.; Torelli, F.

    2004-01-01

    The twin factors of limited investment in electric transmission systems and the overexploitation of electrical resources results in an increase in the need for reactive power to support system voltage profile and to supply loads. It is reasonable to expect that generators and compensators, heavily involved in reactive support on a voluntary basis, will be remunerated for their service by market transactions. This remuneration will depend on the network topology, i.e. of buyers, sellers and reactive injection locations, on the active power exchanged and the reactive power required by loads. All these aspects are taken into account in developing a methodology based on circuit considerations. Using this approach, at a given system operating point characterised by a predefined set of transactions, reactive responsibilities can be formulated as the sum of two terms: one strictly related to transactions and the other dependent on electric network parameters. Test results demonstrate the efficacy of the proposed methodology in sharing reactive power responsibilities in a fair way among market participants. (author)

  8. Reactive power and voltage control strategy based on dynamic and adaptive segment for DG inverter

    Science.gov (United States)

    Zhai, Jianwei; Lin, Xiaoming; Zhang, Yongjun

    2018-03-01

    The inverter of distributed generation (DG) can support reactive power to help solve the problem of out-of-limit voltage in active distribution network (ADN). Therefore, a reactive voltage control strategy based on dynamic and adaptive segment for DG inverter is put forward to actively control voltage in this paper. The proposed strategy adjusts the segmented voltage threshold of Q(U) droop curve dynamically and adaptively according to the voltage of grid-connected point and the power direction of adjacent downstream line. And then the reactive power reference of DG inverter can be got through modified Q(U) control strategy. The reactive power of inverter is controlled to trace the reference value. The proposed control strategy can not only control the local voltage of grid-connected point but also help to maintain voltage within qualified range considering the terminal voltage of distribution feeder and the reactive support for adjacent downstream DG. The scheme using the proposed strategy is compared with the scheme without the reactive support of DG inverter and the scheme using the Q(U) control strategy with constant segmented voltage threshold. The simulation results suggest that the proposed method has a significant improvement on solving the problem of out-of-limit voltage, restraining voltage variation and improving voltage quality.

  9. Reactive Power Compensation Using an Energy Management System

    Science.gov (United States)

    2014-09-01

    compiled to VHDL code using Xilinx System Generator software [12], which is used by the FPGA to command the EMS. The FPGA development board is the middle...controller was implemented in the lab to correct iems because the EMS hardware currently does not have a sensor on the source current. Adding a...shown in Figure 13 as φsource changes over time. 20 The function of the power factor correction diagram shown in Figure 14 is to implement the power

  10. Calculation methods of reactivity using derivatives of nuclear power and Filter fir

    International Nuclear Information System (INIS)

    Diaz, Daniel Suescun

    2007-01-01

    This work presents two new methods for the solution of the inverse point kinetics equation. The first method is based on the integration by parts of the integral of the inverse point kinetics equation, which results in a power series in terms of the nuclear power in time dependence. Applying some conditions to the nuclear power, the reactivity is represented as first and second derivatives of this nuclear power. This new calculation method for reactivity has special characteristics, amongst which the possibility of using different sampling periods, and the possibility of restarting the calculation, after its interruption associated it with a possible equipment malfunction, allowing the calculation of reactivity in a non-continuous way. Apart from this reactivity can be obtained with or without dependency on the nuclear power memory. The second method is based on the Laplace transform of the point kinetics equations, resulting in an expression equivalent to the inverse kinetics equation as a function of the power history. The reactivity can be written in terms of the summation of convolution with response to impulse, characteristic of a linear system. For its digital form the Z-transform is used, which is the discrete version of the Laplace transform. In this method it can be pointed out that the linear part is equivalent to a filter named Finite Impulse Response (Fir). The Fir filter will always be, stable and non-varying in time, and, apart from this, it can be implemented in the non-recursive way. This type of implementation does not require feedback, allowing the calculation of reactivity in a continuous way. The proposed methods were validated using signals with random noise and showing the relationship between the reactivity difference and the degree of the random noise. (author)

  11. Compatibility of Space Nuclear Power Plant Materials in an Inert He/Xe Working Gas Containing Reactive Impurities

    International Nuclear Information System (INIS)

    MM Hall

    2006-01-01

    A major materials selection and qualification issue identified in the Space Materials Plan is the potential for creating materials compatibility problems by combining dissimilar reactor core, Brayton Unit and other power conversion plant materials in a recirculating, inert He/Xe gas loop containing reactive impurity gases. Reported here are results of equilibrium thermochemical analyses that address the compatibility of space nuclear power plant (SNPP) materials in high temperature impure He gas environments. These studies provide early information regarding the constraints that exist for SNPP materials selection and provide guidance for establishing test objectives and environments for SNPP materials qualification testing

  12. Active and reactive power neurocontroller for grid-connected photovoltaic generation system

    Directory of Open Access Journals (Sweden)

    I. Abadlia

    2016-03-01

    Full Text Available Many researchers have contributed to the development of a firm foundation for analysis and design of control applications in grid-connected renewable energy sources. This paper presents an intelligent control algorithm fond on artificial neural networks for active and reactive power controller in grid-connected photovoltaic generation system. The system is devices into two parts in which each part contains an inverter with control algorithm. A DC/DC converter in output voltage established by control magnitude besides maximum power point tracker algorithm always finds optimal power of the PV array in use. A DC/AC hysteresis inverter designed can synchronize a sinusoidal current output with the grid voltage and accurate an independent active and reactive power control. Simulation results confirm the validation of the purpose. Neurocontroller based active and reactive power presents an efficiency control that guarantees good response to the steps changing in active and reactive power with an acceptable current/voltage synchronism. In this paper the power circuit and the control system of the presented grid-connected photovoltaic generation system is simulated and tested by MatLab/Simulink.

  13. Power system services provided by inverter connected distributed energy resources

    DEFF Research Database (Denmark)

    For the last few years there has been a significant increase of DER units in Denmark, of those units more and more are connected to the power system using inverters. These inverter connected units have the potential to support the electrical power system with various power system services. One...

  14. Brayton Power Conversion Unit Tested: Provides a Path to Future High-Power Electric Propulsion Missions

    Science.gov (United States)

    Mason, Lee S.

    2003-01-01

    Closed-Brayton-cycle conversion technology has been identified as an excellent candidate for nuclear electric propulsion (NEP) power conversion systems. Advantages include high efficiency, long life, and high power density for power levels from about 10 kWe to 1 MWe, and beyond. An additional benefit for Brayton is the potential for the alternator to deliver very high voltage as required by the electric thrusters, minimizing the mass and power losses associated with the power management and distribution (PMAD). To accelerate Brayton technology development for NEP, the NASA Glenn Research Center is developing a low-power NEP power systems testbed that utilizes an existing 2- kWe Brayton power conversion unit (PCU) from previous solar dynamic technology efforts. The PCU includes a turboalternator, a recuperator, and a gas cooler connected by gas ducts. The rotating assembly is supported by gas foil bearings and consists of a turbine, a compressor, a thrust rotor, and an alternator on a single shaft. The alternator produces alternating-current power that is rectified to 120-V direct-current power by the PMAD unit. The NEP power systems testbed will be utilized to conduct future investigations of operational control methods, high-voltage PMAD, electric thruster interactions, and advanced heat rejection techniques. The PCU was tested in Glenn s Vacuum Facility 6. The Brayton PCU was modified from its original solar dynamic configuration by the removal of the heat receiver and retrofitting of the electrical resistance gas heater to simulate the thermal input of a steady-state nuclear source. Then, the Brayton PCU was installed in the 3-m test port of Vacuum Facility 6, as shown. A series of tests were performed between June and August of 2002 that resulted in a total PCU operational time of about 24 hr. An initial test sequence on June 17 determined that the reconfigured unit was fully operational. Ensuing tests provided the operational data needed to characterize PCU

  15. Voltage Control of Distribution Grids with Multi-Microgrids Using Reactive Power Management

    Directory of Open Access Journals (Sweden)

    WLODARCZYK, P.

    2015-02-01

    Full Text Available Low-voltage Microgrids can be valuable sources of ancillary services for the Distribution System Operators (DSOs. The aim of this paper was to study if and how multi-microgrids can contribute to Voltage Control (VC in medium-voltage distribution grids by means of reactive power generation and/or absorption. The hierarchical control strategy was proposed with the main focus on the tertiary control which was defined as optimal power flow problem. The interior-point algorithm was applied to optimise experimental benchmark grid with the presence of Distributed Energy Resources (DERs. Moreover, two primary objectives were formulated: active power losses and amount of reactive power used to reach the voltage profile. As a result the active power losses were minimised to the high extent achieving the savings around 22% during entire day.

  16. MILP Approach for Bilevel Transmission and Reactive Power Planning Considering Wind Curtailment

    DEFF Research Database (Denmark)

    Ugranli, Faruk; Karatepe, Engin; Nielsen, Arne Hejde

    2017-01-01

    In this study, two important planning problems in power systems that are transmission expansion and reactive power are formulated as a mixed-integer linear programming taking into account the bilevel structure due to the consideration of market clearing under several load-wind scenarios....... The objective of the proposed method is to minimize the installation cost of transmission lines, reactive power sources, and the annual operation costs of conventional generators corresponding to the curtailed wind energy while maintaining the reliable system operation. Lower level problems of the bilevel...... structure are designated for the market clearing which is formulated by using the linearized optimal power flow equations. In order to obtain mixed-integer linear programming formulation, the so-called lower level problems are represented by using primal-dual formulation. By using the proposed method, power...

  17. Optimal Coordinated EV Charging with Reactive Power Support in Constrained Distribution Grids

    Energy Technology Data Exchange (ETDEWEB)

    Paudyal, Sumit; Ceylan, Oğuzhan; Bhattarai, Bishnu P.; Myers, Kurt S.

    2017-07-01

    Electric vehicle (EV) charging/discharging can take place in any P-Q quadrants, which means EVs could support reactive power to the grid while charging the battery. In controlled charging schemes, distribution system operator (DSO) coordinates with the charging of EV fleets to ensure grid’s operating constraints are not violated. In fact, this refers to DSO setting upper bounds on power limits for EV charging. In this work, we demonstrate that if EVs inject reactive power into the grid while charging, DSO could issue higher upper bounds on the active power limits for the EVs for the same set of grid constraints. We demonstrate the concept in an 33-node test feeder with 1,500 EVs. Case studies show that in constrained distribution grids in coordinated charging, average costs of EV charging could be reduced if the charging takes place in the fourth P-Q quadrant compared to charging with unity power factor.

  18. Transient Control of Synchronous Machine Active and Reactive Power in Micro-grid Power Systems

    Science.gov (United States)

    Weber, Luke G.

    There are two main topics associated with this dissertation. The first is to investigate phase-to-neutral fault current magnitude occurring in generators with multiple zero-sequence current sources. The second is to design, model, and tune a linear control system for operating a micro-grid in the event of a separation from the electric power system. In the former case, detailed generator, AC8B excitation system, and four-wire electric power system models are constructed. Where available, manufacturers data is used to validate the generator and exciter models. A gain-delay with frequency droop control is used to model an internal combustion engine and governor. The four wire system is connected through a transformer impedance to an infinite bus. Phase-to-neutral faults are imposed on the system, and fault magnitudes analyzed against three-phase faults to gauge their severity. In the latter case, a balanced three-phase system is assumed. The model structure from the former case - but using data for a different generator - is incorporated with a model for an energy storage device and a net load model to form a micro-grid. The primary control model for the energy storage device has a high level of detail, as does the energy storage device plant model in describing the LC filter and transformer. A gain-delay battery and inverter model is used at the front end. The net load model is intended to be the difference between renewable energy sources and load within a micro-grid system that has separated from the grid. Given the variability of both renewable generation and load, frequency and voltage stability are not guaranteed. This work is an attempt to model components of a proposed micro-grid system at the University of Wisconsin Milwaukee, and design, model, and tune a linear control system for operation in the event of a separation from the electric power system. The control module is responsible for management of frequency and active power, and voltage and reactive

  19. Change in CANDU-6 reactivity following a power reduction at low PHT purity

    International Nuclear Information System (INIS)

    Whitlock, J.J.; Soulard, M.R.; Baudouin, A.

    1995-01-01

    The reactivity effect of a power reduction in CANDU-6 is examined using a three-dimensional, steady-state, coupled neutronics/thermalhydraulics methodology, starting from a global irradiation distribution matched to site data. The power reduction is sufficient to suppress coolant boiling in the fuel channels, and thus the significant parameters affecting reactivity are an increase in coolant density and a decrease in fuel temperature. These individual components are estimated using infinite-lattice-cell methodology. The effect of using newer methodology, particularly for the thermalhydraulic analysis, is examined by comparison with previous simulations. (author). 10 refs., 7 tabs., 1 fig

  20. A fast method for optimal reactive power flow solution

    Energy Technology Data Exchange (ETDEWEB)

    Sadasivam, G; Khan, M A [Anna Univ., Madras (IN). Coll. of Engineering

    1990-01-01

    A fast successive linear programming (SLP) method for minimizing transmission losses and improving the voltage profile is proposed. The method uses the same compactly stored, factorized constant matrices in all the LP steps, both for power flow solution and for constructing the LP model. The inherent oscillatory convergence of SLP methods is overcome by proper selection of initial step sizes and their gradual reduction. Detailed studies on three systems, including a 109-bus system, reveal the fast and reliable convergence property of the method. (author).

  1. Optimal Control of Wind Farms for Coordinated TSO-DSO Reactive Power Management

    Directory of Open Access Journals (Sweden)

    David Sebastian Stock

    2018-01-01

    Full Text Available The growing importance of renewable generation connected to distribution grids requires an increased coordination between transmission system operators (TSOs and distribution system operators (DSOs for reactive power management. This work proposes a practical and effective interaction method based on sequential optimizations to evaluate the reactive flexibility potential of distribution networks and to dispatch them along with traditional synchronous generators, keeping to a minimum the information exchange. A modular optimal power flow (OPF tool featuring multi-objective optimization is developed for this purpose. The proposed method is evaluated for a model of a real German 110 kV grid with 1.6 GW of installed wind power capacity and a reduced order model of the surrounding transmission system. Simulations show the benefit of involving wind farms in reactive power support reducing losses both at distribution and transmission level. Different types of setpoints are investigated, showing the feasibility for the DSO to fulfill also individual voltage and reactive power targets over multiple connection points. Finally, some suggestions are presented to achieve a fair coordination, combining both TSO and DSO requirements.

  2. Neutron and thermo - hydraulic model of a reactivity transient in a nuclear power plant fuel element

    International Nuclear Information System (INIS)

    Oliva, Jose de Jesus Rivero

    2012-01-01

    A reactivity transient without reactor scram was modeled and calculated using analytical expressions for the space distributions of the temperature fields, combined with discrete numerical calculations for the time dependences of thermal power and temperatures. The transient analysis covered the time dependencies of reactivity, global thermal power, fuel heat flux and temperatures in fuel, cladding and cooling water. The model was implemented in Microsoft Office Excel, dividing the Excel file in several separated worksheets for input data, initial steady-state calculations, calculation of parameters non-depending on eigenvalues, eigenvalues determination, calculation of parameters depending on eigenvalues, transient calculation and graphical representation of intermediate and final results. The results show how the thermal power reaches a new equilibrium state due to the negative reactivity feedback derived from the fuel temperature increment. Nevertheless, the reactor mean power increases 40% during the first second and, in the hottest channel, the maximum fuel temperature goes to a significantly high value, slightly above 2100 deg C, after 8 seconds of transient. Consequently, the results confirm that certain degree of fuel damage could be expected in case of a reactor scram failure. Once the basic model has being established the scope of accidents for future analyses can be extended, modifying the nuclear power behavior (reactivity) during transient and the boundary conditions for coolant temperature. A more complex model is underway for an annular fuel element. (author)

  3. Literature Survey on Operational Voltage Control and Reactive Power Management on Transmission and Sub-Transmission Networks

    Energy Technology Data Exchange (ETDEWEB)

    Elizondo, Marcelo A.; Samaan, Nader A.; Makarov, Yuri V.; Holzer, Jesse T.; Vallem, Mallikarjuna R.; Huang, Renke; Vyakaranam, Bharat GNVSR; Ke, Xinda; Pan, Feng

    2017-10-02

    Voltage and reactive power system control is generally performed following usual patterns of loads, based on off-line studies for daily and seasonal operations. This practice is currently challenged by the inclusion of distributed renewable generation, such as solar. There has been focus on resolving this problem at the distribution level; however, the transmission and sub-transmission levels have received less attention. This paper provides a literature review of proposed methods and solution approaches to coordinate and optimize voltage control and reactive power management, with an emphasis on applications at transmission and sub-transmission level. The conclusion drawn from the survey is that additional research is needed in the areas of optimizing switch shunt actions and coordinating all available resources to deal with uncertain patterns from increasing distributed renewable generation in the operational time frame. These topics are not deeply explored in the literature.

  4. Reduced Cost of Reactive Power in Doubly Fed Induction Generator Wind Turbine System with Optimized Grid Filter

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Franke, Toke

    2014-01-01

    The modern grid requirement has caused that the wind power system behaves more like conventional rotating generators and it is able to support certain amount of the reactive power. For a typical doubly-fed induction generator wind turbine system, the reactive power can be supported either through...... for the generator and the wind power converter in terms of the reactive power done by the rotor-side converter or the grid-side converter with various grid filters. Afterwards, the annual energy loss is also estimated based on yearly wind profile. Finally, experimental results of the loss distribution are performed...... the rotor-side converter or the grid-side converter. This paper firstly compares the current ripples and supportive reactive power ranges between the conventional L and optimized LCL filter, if the reactive power is injected from the grid-side converter. Then, the loss distribution is evaluated both...

  5. Reduced Cost of Reactive Power in Doubly Fed Induction Generator Wind Turbine System With Optimized Grid Filter

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Franke, Toke

    2015-01-01

    The modern grid requirement has caused that the wind power system behaves more like conventional rotating generators, and it is able to support certain amount of the reactive power. For a typical doubly fed induction generator (DFIG) wind turbine system, the reactive power can be supported either...... for the generator and the wind power converter in terms of the reactive power done by the rotor-side converter or the grid-side converter with various grid filters. Afterward, the annual energy loss is also estimated based on yearly wind profile. Finally, experimental results of the loss distribution are performed...... through the rotor-side converter or the grid-side converter. This paper first compares the current ripples and supportive reactive power ranges between the conventional L and optimized LCL filter, if the reactive power is injected from the grid-side converter. Then, the loss distribution is evaluated both...

  6. Settlement of reactive power compensation in the light of white certificates

    Directory of Open Access Journals (Sweden)

    Zajkowski Konrad

    2017-01-01

    The detailed method and an estimation method proposed for the determination of savings on active energy as a result of the reactive power compensation carried out possess some errors and inconvenience. The detailed method requires knowledge of the network topology and a determination of reactive power Q at each point of the network. The estimation method of analysis is easy in execution, especially if the consumer of energy is the main or the most significant purchaser of electricity in the network. Unfortunately, this latter method can be used only for activities that do not require high computational accuracy. The results obtained by this method are approximate values that can be used for the calculation of economic indicators. The estimation method is suitable for determining the number of white certificates when a power audit concerns a recipient of electricity, the structure of which is a large number of divisions scattered at many different locations in the power system.

  7. Design and Optimisation of a Simple Filter Group for Reactive Power Distribution

    Directory of Open Access Journals (Sweden)

    Ryszard Klempka

    2016-01-01

    Full Text Available Basic methods are presented to design a simple filter group and a method of shaping the resultant of the filter group’s impedance characteristics (distribution of the characteristics’ extremes and then project equations were transformed into a uniform, common form that addresses issues of the reactive power distribution between component filters. The analysis also takes into account the filters’ detuning from the reduced harmonics and quality factors of passive elements. Another important factor of the analysis considered was the power grid equivalent impedance affecting the filtration effectiveness. A criterion for the filter group’s filtration effectiveness evaluation was proposed and optimisation was completed for the reactive power distribution between separate filters in the function of the power grid’s equivalent inductance.

  8. Opposition-Based Improved PSO for Optimal Reactive Power Dispatch and Voltage Control

    Directory of Open Access Journals (Sweden)

    Shengrang Cao

    2015-01-01

    Full Text Available An opposition-based improved particle swarm optimization algorithm (OIPSO is presented for solving multiobjective reactive power optimization problem. OIPSO uses the opposition learning to improve search efficiency, adopts inertia weight factors to balance global and local exploration, and takes crossover and mutation and neighborhood model strategy to enhance population diversity. Then, a new multiobjective model is built, which includes system network loss, voltage dissatisfaction, and switching operation. Based on the market cost prices, objective functions are converted to least-cost model. In modeling process, switching operation cost is described according to the life cycle cost of transformer, and voltage dissatisfaction penalty is developed considering different voltage quality requirements of customers. The experiment is done on the new mathematical model. Through the simulation of IEEE 30-, 118-bus power systems, the results prove that OIPSO is more efficient to solve reactive power optimization problems and the model is more accurate to reflect the real power system operation.

  9. Use of reactivity constraints for the automatic control of reactor power

    International Nuclear Information System (INIS)

    Bernard, J.A.; Lanning, D.D.; Ray, A.

    1985-01-01

    A theoretical framework for the automatic control of reactor power has been developed and experimentally evaluated on the 5 MWt Research Reactor that is operated by the Massachusetts Institute of Technology. The controller functions by restricting the net reactivity so that it is always possible to make the reactor period infinite at the desired termination point of a transient by reversing the direction of motion of whatever control mechanism is associated with the controller. This capability is formally designated as ''feasibility of control''. It has been shown experimentally that maintenance of feasibility of control is a sufficient condition for the automatic control of reactor power. This research should be of value in the design of closed-loop controllers, in the creation of reactivity displays, in the provision of guidance to operators regarding the timing of reactivity changes, and as an experimental envelope within which alternate control strategies can be evaluated

  10. Reactive Power Control for Improving Wind Turbine System Behavior Under Grid Faults

    DEFF Research Database (Denmark)

    Rodriguez, P.; Timbus, A.; Teodorescu, Remus

    2009-01-01

    This letter aims to present a generalized vector-based formulation for calculating the grid-side current reference to control reactive power delivered to the grid. Strategies for current reference generation were implemented on the abc stationary reference frame, and their effectivenesswas...... demonstrated experimentally, perhaps validating the theoretical analysis even under grid fault conditions....

  11. 77 FR 21555 - Reactive Power Resources; Supplemental Notice of Technical Conference

    Science.gov (United States)

    2012-04-10

    .... This panel will discuss: Methods used to determine the reactive power requirements for a transmission... Jenkins, Director--Utility Interconnection, First Solar Kris Zadlo, Vice President, Invenergy Richard..., Director--Utility Interconnection, First Solar Michael Jacobs, Director Market and Regulatory Policy...

  12. Settlement of reactive power compensation in the light of white certificates

    Science.gov (United States)

    Zajkowski, Konrad

    2017-10-01

    The article discusses the problem of the determination of savings on active energy as a result of a reactive power compensation. Statutory guidance on the required energy audit to obtain white certificates in the European Union was followed. The analysis was made on the basis of the Polish Law. The paper presents a detailed analytical method and an estimation method taking into account the impact on the line, the transformer and the generator. According to the relevant guidelines in the European Union, the reduction of CO2 emissions by calculating the saving of active power should be determined. The detailed method and an estimation method proposed for the determination of savings on active energy as a result of the reactive power compensation carried out possess some errors and inconvenience. The detailed method requires knowledge of the network topology and a determination of reactive power Q at each point of the network. The estimation method of analysis is easy in execution, especially if the consumer of energy is the main or the most significant purchaser of electricity in the network. Unfortunately, this latter method can be used only for activities that do not require high computational accuracy. The results obtained by this method are approximate values that can be used for the calculation of economic indicators. The estimation method is suitable for determining the number of white certificates when a power audit concerns a recipient of electricity, the structure of which is a large number of divisions scattered at many different locations in the power system.

  13. Positional differences in reactive hyperemia provide insight into initial phase of exercise hyperemia.

    Science.gov (United States)

    Jasperse, Jeffrey L; Shoemaker, J Kevin; Gray, Eric J; Clifford, Philip S

    2015-09-01

    Studies have reported a greater blood flow response to muscle contractions when the limb is below the heart compared with above the heart, and these results have been interpreted as evidence for a skeletal muscle pump contribution to exercise hyperemia. If limb position affects the blood flow response to other vascular challenges such as reactive hyperemia, this interpretation may not be correct. We hypothesized that the magnitude of reactive hyperemia would be greater with the limb below the heart. Brachial artery blood flow (Doppler ultrasound) and blood pressure (finger-cuff plethysmography) were measured in 10 healthy volunteers. Subjects lay supine with one arm supported in two different positions: above or below the heart. Reactive hyperemia was produced by occlusion of arterial inflow for varying durations: 0.5 min, 1 min, 2 min, or 5 min in randomized order. Peak increases in blood flow were 77 ± 11, 178 ± 24, 291 ± 25, and 398 ± 33 ml/min above the heart and 96 ± 19, 279 ± 62, 550 ± 60, and 711 ± 69 ml/min below the heart (P different responses depending on limb position. To determine whether these differences were due to mechanisms intrinsic to the arterial wall, a second set of experiments was performed in which acute intraluminal pressure reduction for 0.5 min, 1 min, 2 min, or 5 min was performed in isolated rat soleus feed arteries (n = 12). The magnitude of dilation upon pressure restoration was greater when acute pressure reduction occurred from 85 mmHg (mimicking pressure in the arm below the heart; 28.3 ± 7.9, 37.5 ± 5.9, 55.1 ± 9.9, and 68.9 ± 8.6% dilation) than from 48 mmHg (mimicking pressure in the arm above the heart; 20.8 ± 4.8, 22.6 ± 4.4, 31.2 ± 5.8, and 49.2 ± 7.1% dilation). These data support the hypothesis that arm position differences in reactive hyperemia are at least partially mediated by mechanisms intrinsic to the arterial wall. Overall, these results suggest the need to reevaluate studies employing positional

  14. National energy policy provides scant power direction. [Canada

    Energy Technology Data Exchange (ETDEWEB)

    1976-05-07

    More federal direction on electric power developments was expected than actually materialized in the national energy policy released recently by Energy, Mines, and Resources. None of the primary objectives was specifically geared to improving the sagging power outlook. The five targets mentioned would have varying positive influences on Canadian power security if achieved, but oil and gas problems stole the spotlight. Failure of a national energy grid to make the top priority list was a disappointment. Observers had been expecting more prominent treatment for grid schemes in light of comments made by energy minister Alastair Gillespie at the recent energy conservation conference in Ottawa. But the strategy paper merely endorses the strengthening of regional interconnections, particularly in eastern Canada, and urges closer coordination among provincial utilities in planning and development. It reveals no new move to spur grid action and only reiterates the federal offer to back 50 percent of interconnection studies and capital costs. The paper does recognize that strengthened regional ties would lead to a form of integrated national system permitting more efficient systems growth, mutual assistance in the event of power failures, and some averaging out of peak and off-peak loads. They would economize on the need for stand-by power and enhance more rational expansion.

  15. Measurement based analysis of active and reactive power losses in a distribution network with wind farms and CHPs

    DEFF Research Database (Denmark)

    Lund, Torsten

    2007-01-01

    The paper presents an investigation of the active and reactive power losses in a distribution network with wind turbines and combined heat and power plants. The investigation is based on 15 min average power measurements and load flow calculations in the power system simulation tool PowerFactory...

  16. Implications for providers of nuclear power plants, materials and services

    International Nuclear Information System (INIS)

    May, D.

    2000-01-01

    BNFL does not agree with the IEA business prediction showing a decline in the share of electricity generated by nuclear power over the next 20 years. On the contrary BNFL believes that lifetime extension and continued new build will help maintain or even increase the share of electricity generated by nuclear power. One reason why new nuclear build programmes have been reduced is because existing reactors are operating for longer and at higher performance than ever before. As reactor lifetimes are extended new business opportunities will emerge concerning the upgrading of different systems from nuclear control systems to steam turbines. (A.C.)

  17. Multi-objective optimal reactive power dispatch to maximize power system social welfare in the presence of generalized unified power flow controller

    Directory of Open Access Journals (Sweden)

    Suresh Chintalapudi Venkata

    2015-09-01

    Full Text Available In this paper a novel non-linear optimization problem is formulated to maximize the social welfare in restructured environment with generalized unified power flow controller (GUPFC. This paper presents a methodology to optimally allocate the reactive power by minimizing voltage deviation at load buses and total transmission power losses so as to maximize the social welfare. The conventional active power generation cost function is modified by combining costs of reactive power generated by the generators, shunt capacitors and total power losses to it. The formulated objectives are optimized individually and simultaneously as multi-objective optimization problem, while satisfying equality, in-equality, practical and device operational constraints. A new optimization method, based on two stage initialization and random distribution processes is proposed to test the effectiveness of the proposed approach on IEEE-30 bus system, and the detailed analysis is carried out.

  18. Optimal reactive power planning for distribution systems considering intermittent wind power using Markov model and genetic algorithm

    Science.gov (United States)

    Li, Cheng

    Wind farms, photovoltaic arrays, fuel cells, and micro-turbines are all considered to be Distributed Generation (DG). DG is defined as the generation of power which is dispersed throughout a utility's service territory and either connected to the utility's distribution system or isolated in a small grid. This thesis addresses modeling and economic issues pertaining to the optimal reactive power planning for distribution system with wind power generation (WPG) units. Wind farms are inclined to cause reverse power flows and voltage variations due to the random-like outputs of wind turbines. To deal with this kind of problem caused by wide spread usage of wind power generation, this thesis investigates voltage and reactive power controls in such a distribution system. Consequently static capacitors (SC) and transformer taps are introduced into the system and treated as controllers. For the purpose of getting optimum voltage and realizing reactive power control, the research proposes a proper coordination among the controllers like on-load tap changer (OLTC), feeder-switched capacitors. What's more, in order to simulate its uncertainty, the wind power generation is modeled by the Markov model. In that way, calculating the probabilities for all the scenarios is possible. Some outputs with consecutive and discrete values have been used for transition between successive time states and within state wind speeds. The thesis will describe the method to generate the wind speed time series from the transition probability matrix. After that, utilizing genetic algorithm, the optimal locations of SCs, the sizes of SCs and transformer taps are determined so as to minimize the cost or minimize the power loss, and more importantly improve voltage profiles. The applicability of the proposed method is verified through simulation on a 9-bus system and a 30-bus system respectively. At last, the simulation results indicate that as long as the available capacitors are able to sufficiently

  19. Experimental evaluation of reactivity constraints for the closed-loop control of reactor power

    International Nuclear Information System (INIS)

    Bernard, J.A.; Lanning, D.D.; Ray, A.

    1984-01-01

    General principles for the closed-loop, digital control of reactor power have been identified, quantitatively enumerated, and experimentally demonstrated on the 5 MWt Research Reactor, MITR-II. The basic concept is to restrict the net reactivity so that it is always possible to make the reactor period infinite at the desired termination point of a transient by reversing the direction of motion of whatever control mechanism is associated with the controller. This capability is formally referred to as ''feasibility of control''. A series of ten experiments have been conducted over a period of eighteen months to demonstrate the efficacy of this property for the automatic control of reactor power. It has been shown that a controller which possesses this property is capable of both raising and lowering power in a safe, efficient manner while using a control rod of varying differential worth, that the reactivity constraints are a sufficient condition for the automatic control of reactor power, and that the use of a controller based on reactivity constraints can prevent overshoots either due to attempts to control a transient with a control rod of insufficient differential worth or due to failure to properly estimate when to commence rod insertion. Details of several of the more significant tests are presented together with a discussion of the rationale for the development of closed-loop control in large commercial power systems. Specific consideration is given to the motivation for designing a controller based on feasibility of control and the associated licensing issues

  20. Combined Active and Reactive Power Control of Wind Farms based on Model Predictive Control

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Wang, Jianhui

    2017-01-01

    This paper proposes a combined wind farm controller based on Model Predictive Control (MPC). Compared with the conventional decoupled active and reactive power control, the proposed control scheme considers the significant impact of active power on voltage variations due to the low X=R ratio...... of wind farm collector systems. The voltage control is improved. Besides, by coordination of active and reactive power, the Var capacity is optimized to prevent potential failures due to Var shortage, especially when the wind farm operates close to its full load. An analytical method is used to calculate...... the sensitivity coefficients to improve the computation efficiency and overcome the convergence problem. Two control modes are designed for both normal and emergency conditions. A wind farm with 20 wind turbines was used to verify the proposed combined control scheme....

  1. Reactive power generation in high speed induction machines by continuously occurring space-transients

    Science.gov (United States)

    Laithwaite, E. R.; Kuznetsov, S. B.

    1980-09-01

    A new technique of continuously generating reactive power from the stator of a brushless induction machine is conceived and tested on a 10-kw linear machine and on 35 and 150 rotary cage motors. An auxiliary magnetic wave traveling at rotor speed is artificially created by the space-transient attributable to the asymmetrical stator winding. At least two distinct windings of different pole-pitch must be incorporated. This rotor wave drifts in and out of phase repeatedly with the stator MMF wave proper and the resulting modulation of the airgap flux is used to generate reactive VA apart from that required for magnetization or leakage flux. The VAR generation effect increases with machine size, and leading power factor operation of the entire machine is viable for large industrial motors and power system induction generators.

  2. EBRPOCO - a program to calculate detailed contributions of power reactivity components of EBR-II

    International Nuclear Information System (INIS)

    Meneghetti, D.; Kucera, D.A.

    1981-01-01

    The EBRPOCO program has been developed to facilitate the calculations of the power coefficients of reactivity of EBR-II loadings. The program enables contributions of various components of the power coefficient to be delineated axially for every subassembly. The program computes the reactivity contributions of the power coefficients resulting from: density reduction of sodium coolant due to temperature; displacement of sodium coolant by thermal expansions of cladding, structural rods, subassembly cans, and lower and upper axial reflectors; density reductions of these steel components due to temperature; displacement of bond-sodium (if present) in gaps by differential thermal expansions of fuel and cladding; density reduction of bond-sodium (if present) in gaps due to temperature; free axial expansion of fuel if unrestricted by cladding or restricted axial expansion of fuel determined by axial expansion of cladding. Isotopic spatial contributions to the Doppler component my also be obtained. (orig.) [de

  3. Long term storage effects of irradiated fuel elements on power distribution and reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Ponzoni Filho, P.; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso T.I.C.; Fernandes Vanderlei Borba [FURNAS, Rio de Janeiro, RJ (Brazil); Fetterman, R.J. [Westinghouse Electric Corp., Pittsburgh, PA (United States)

    1995-12-31

    The ALPHA/PHOENIX-P/ANC (APA) code package was used to calculate the pin by pin power distribution and reactivity for Angra 1 Power Plant, Cycle 5. The Angra 1 Cycle 5 core was loaded with several irradiated fuel elements which were stored in the Spent Fuel Pool (SFP) for more than 8 years. Generally, neutronic codes take into account the buildup and depletion of just a few key fission, products such as Sm-149. In this paper it is shown that the buildup effects of other fission products must be considered for fuel which has been out of the core for significant periods of time. Impacts of these other fission products can change core reactivity and power distribution. (author). 3 refs, 4 figs, 4 tabs.

  4. Long term storage effects of irradiated fuel elements on power distribution and reactivity

    International Nuclear Information System (INIS)

    Ponzoni Filho, P.; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso T.I.C.; Fernandes Vanderlei Borba; Fetterman, R.J.

    1995-01-01

    The ALPHA/PHOENIX-P/ANC (APA) code package was used to calculate the pin by pin power distribution and reactivity for Angra 1 Power Plant, Cycle 5. The Angra 1 Cycle 5 core was loaded with several irradiated fuel elements which were stored in the Spent Fuel Pool (SFP) for more than 8 years. Generally, neutronic codes take into account the buildup and depletion of just a few key fission, products such as Sm-149. In this paper it is shown that the buildup effects of other fission products must be considered for fuel which has been out of the core for significant periods of time. Impacts of these other fission products can change core reactivity and power distribution. (author). 3 refs, 4 figs, 4 tabs

  5. Reactivity and Power Distribution Management in LEU-loaded Linear B and BR

    International Nuclear Information System (INIS)

    Hartanto, Donny; Kim, Yonghee

    2013-01-01

    In this paper, the relatively high excess reactivity issue during the initial transitional period was addressed. The design target is to achieve a maximum excess reactivity of about 1.0 dollar to prevent the possibility of the prompt jump critical accident. The initial core is divided into 2 radial Zr-zones in order to reduce the excess reactivity. By doing this, the power profile at the BOC can also be flattened. After the optimum initial core configuration has been found, the blanket region is also divided into 2 radial Zr-zones in order to flatten the power distribution at EOC. The neutronic analyses were all performed using the Monte Carlo code McCARD with ENDF-B/VII.0 library. It was found that by using the concave Zr-zoning in the initial core of B and BR, the maximum excess reactivity can be effectively lowered. The radial power profile can also be successfully flattened by using the Zr-zoning and concave initial core. The concave concept deserves more investigations for better performances of the B and BR core

  6. Sensitivity analysis of power excursion in RSG-GAS reactor due to reactivity insertion

    International Nuclear Information System (INIS)

    Pinem, Surian; Sembiring, Tagor Malem

    2002-01-01

    Reactor kinetics has a very important role in reactor operation safety and nuclear reactor control. One of the important aspects in reactor kinetics is power behavior as function of time due to chain reaction in the core. The calculation was performed using kinetic equation and feedback reactivity and evaluated using static power coefficient. Analysis was performed for oxide 250 g, silicide 250 g and silicide 300 g fuel elements with insertion of positive reactivity, negative reactivity and reactivity close to delay neutron fraction. The calculation of power excursion sensitivity showed that the insertion of 0,5 % Δk/k, in the fuel element of silicide 300 g is bigger 5 % than the one of oxide 250 g or silicide 250 g. If inserted by - 1,2 % Δk/k, there is no change among three fuel elements. Therefore, in kinetic point of view, it is showed there is no significant influence in the RSG-GAS reactor operation safety is the current core of oxide 250 g is converted to silicide 250 g or to silicide 300 g

  7. Core concept of fast power reactor with zero sodium void reactivity

    International Nuclear Information System (INIS)

    Matveev, V.I.; Chebeskov, A.N.; Krivitsky, I.Y.

    1991-01-01

    The paper presents a core concept of BN-800 - type fast power reactor with zero sodium void reactivity (SVR). Consideration is given to the layout-and some design features of such a core. Some considerations on the determination of the required SVR value as one of the fast reactor safety criteria in accidents with coolant boiling are presented. Some methodical considerations an the development of calculation models that give a correct description of the new core features are stated. The results of the integral SVR calculation studies are included. reactivity excursions under different scenarios of sodium boiling are estimated, some corrections into the calculated SVR value are discussed. (author)

  8. Effect of reactivity insertion rate on peak power and temperatures in swimming pool type research reactor

    International Nuclear Information System (INIS)

    Khan, L.A.; Jabbar, A.; Anwar, A.R.; Ahmad, N.

    1998-01-01

    It is essential to study the reactor behavior under different accidental conditions and take proper measures for its safe operation. We have studied the effect of reactivity insertion, with and without scram conditions, on peak power and temperatures of fuel, cladding and coolant in typical swimming pool type research reactor. The reactivity ranging from 1 $ to 2 $ and insertion times from 0.25 to 1 second have been considered. The computer code PARET has been used and results are presented in this article. (author)

  9. An Integral Model to Provide Reactive and Proactive Services in an Academic CSIRT Based on Business Intelligence

    OpenAIRE

    Walter Fuertes; Francisco Reyes; Paúl Valladares; Freddy Tapia; Theofilos Toulkeridis; Ernesto Pérez

    2017-01-01

    Cyber-attacks have increased in severity and complexity. That requires, that the CERT/CSIRT research and develops new security tools. Therefore, our study focuses on the design of an integral model based on Business Intelligence (BI), which provides reactive and proactive services in a CSIRT, in order to alert and reduce any suspicious or malicious activity on information systems and data networks. To achieve this purpose, a solution has been assembled, that generates information stores, bein...

  10. Coordinated Volt/Var Control in Distribution Systems with Distributed Generations Based on Joint Active and Reactive Powers Dispatch

    Directory of Open Access Journals (Sweden)

    Abouzar Samimi

    2016-01-01

    Full Text Available One of the most significant control schemes in optimal operation of distribution networks is Volt/Var control (VVC. Owing to the radial structure of distribution systems and distribution lines with a small X/R ratio, the active power scheduling affects the VVC issue. A Distribution System Operator (DSO procures its active and reactive power requirements from Distributed Generations (DGs along with the wholesale electricity market. This paper proposes a new operational scheduling method based on a joint day-ahead active/reactive power market at the distribution level. To this end, based on the capability curve, a generic reactive power cost model for DGs is developed. The joint active/reactive power dispatch model presented in this paper motivates DGs to actively participate not only in the energy markets, but also in the VVC scheme through a competitive market. The proposed method which will be performed in an offline manner aims to optimally determine (i the scheduled active and reactive power values of generation units; (ii reactive power values of switched capacitor banks; and (iii tap positions of transformers for the next day. The joint active/reactive power dispatch model for daily VVC is modeled in GAMS and solved with the DICOPT solver. Finally, the plausibility of the proposed scheduling framework is examined on a typical 22-bus distribution test network over a 24-h period.

  11. An Optimized Reactive Power Control of Distributed Solar Inverters in Low Voltage Networks

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

    2011-01-01

    This study examines the reactive power ancillary services of solar inverters which are connected to low voltage (LV) distribution networks by giving attention to the grid voltage support service and grid losses. Two typical reference LV distribution network models as suburban and farm...... are introduced from the literature in order to evaluate contribution of two static droop strategies cosφ(P) and Q(U) on the grid voltage. Photovoltaic (PV) hosting capacities of the suburban and farm networks are estimated and the most predominant limitations of connecting more solar inverters are emphasized...... for each network type. Regarding the overloading of MV/LV distribution transformers, overloading of lines and the grid overvoltage limitations, new local grid voltage support methods (cosφ(P,U) and Q(U,P)) are also proposed. Resulting maximum allowable penetration levels with different reactive power...

  12. Breast milk provides better antioxidant power than does formula.

    Science.gov (United States)

    Aycicek, Ali; Erel, Ozcan; Kocyigit, Abdurrahim; Selek, Sahbettin; Demirkol, Mehmet Resit

    2006-06-01

    We examined the effect of breast milk on plasma total antioxidant capacity (TAC), total peroxide (TP), and oxidative stress index (OSI), which are biomarkers of oxidative status. Fifty-four healthy term infants 3 to 6 mo of age were fed breast milk or a cow's milk modified formula. Plasma TAC, vitamin C, albumin, bilirubin, and uric acid levels were measured as indexes of antioxidative markers. Plasma TP levels were measured as an oxidative stress marker. The OSI was calculated to assess oxidative status. No significant differences were observed between groups with respect to growth or anthropometric measurements. Plasma uric acid, total protein, and albumin concentrations were slightly higher in the breast-fed group than in the formula-fed group. There was a positive correlation between infant's age and serum albumin levels; between TAC and plasma uric acid, albumin, and total bilirubin; and between plasma iron and TP levels in both groups (r > 0.256, P antioxidant power than does formula.

  13. Fast Reactive Power Sharing, Circulating Current and Resonance Suppression for Parallel Inverters Using Resistive-Capacitive Output Impedance

    DEFF Research Database (Denmark)

    Chen, Yandong; Guerrero, Josep M.; Shuai, Zhikang

    2016-01-01

    In this paper, an inverter using resistivecapacitive output impedance (RC-type inverter) is proposed not only to provide fast reactive power sharing to support microgrid voltage, and but also to reduce circulating currents and damp high-frequency resonances among inverters. Introducing the RC......-frequency resonances among parallel inverters are quantitatively analyzed. The control parameters are systematically selected, and effect of virtual complex impedance on the inverter output voltage is depicted. The RC-type inverter can reduce circulating currents and damp resonances due to different equivalent output...

  14. Modified Monkey Optimization Algorithm for Solving Optimal Reactive Power Dispatch Problem

    Directory of Open Access Journals (Sweden)

    Kanagasabai Lenin

    2015-04-01

    Full Text Available In this paper, a novel approach Modified Monkey optimization (MMO algorithm for solving optimal reactive power dispatch problem has been presented. MMO is a population based stochastic meta-heuristic algorithm and it is inspired by intelligent foraging behaviour of monkeys. This paper improves both local leader and global leader phases.  The proposed (MMO algorithm has been tested in standard IEEE 30 bus test system and simulation results show the worthy performance of the proposed algorithm in reducing the real power loss.

  15. Investigation of Reactive Power Control Effects on Flicker and Harmonics Emission of a DFIG Wind Turbine

    Directory of Open Access Journals (Sweden)

    Amir Nagizadeh Ghoogdareh

    2013-01-01

    Full Text Available One of the most important power quality aspects in wind farms is voltage fluctuation or flicker which should be investigated due to the nature of wind speed variations. These variations result in power and voltage fluctuations at the load bus. Moreover, the wind generation systems may be assumed as a harmonics source because of their power electronic converters. There are numerous factors that affect flicker and harmonic emission of grid-connected wind turbines during continuous operation, such as wind characteristics (e.g. mean wind speed, turbulence intensity, type of generator and grid conditions (e.g. short circuit capacity, grid impedance angle. In this paper, an IEC based flickermeter is first modeled and then a variable speed wind turbine has been simulated by Matlab/Simulink software. The flicker and harmonics emissions of wind turbines equipped with DFIG during continuous operation and using output reactive control are investigated. The simulation results show that control of wind turbine output reactive power is an effective means for flicker mitigation during continuous operation. However, there should be a compromise between flicker reduction and harmonics level increase to enhance the whole power quality of wind turbine.

  16. Distributed control of hybrid AC microgrids with dynamic active and reactive power capacity tuning

    DEFF Research Database (Denmark)

    Nutkani, Inam Ullah; Loh, Poh Chiang; Blaabjerg, Frede

    2012-01-01

    Microgrids comprise of emerging generation technologies such as fuel cell, solar PV, wind turbine generator, storage and loads. They can, in principle, operate at different voltages and frequencies. Tying them either to the mains grid or among themselves would certainly require some interlinking...... power converters, whose control should preferably be done autonomously without demanding communication links. This paper proposes distributed control for power management between two Microgrids interlinked through inverters. The control scheme aims to reduce the reactive power loading stress on DERs...... and also allows active power transfer from overloaded grid to under- loaded grid. The performance of proposed control has been verified in simulation and through a scaled-down experimental system....

  17. Lanthanide ions (III) as sensitizers of melatonin oxidation in reaction mixtures providing reactive species of oxygen and nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Kaczmarek, Małgorzata, E-mail: mkaczmar@amu.edu.pl

    2015-06-15

    Chemiluminescence (CL) of the reactive systems providing strong oxidants (reactive species of oxygen and nitrogen) containing lanthanide ions (III) and melatonin, was studied. Kinetic curves of emission decay and spectral distributions of chemiluminescence were obtained. Analysis of differences in the intensity of chemiluminescence and CL spectra proved that excitation of Tb(III) and Dy(III) ions takes place with the energy transfer from the products of melatonin oxidation: N{sup 1}-acetyl-N{sup 2}-formyl-5-methoxykynuramine (AFMK) and N{sup 1}-acetyl-5-methoxykynuramine (AMK) to the lanthanide ions. In the system Fe(II)/Fe(III)–H{sub 2}O{sub 2}–Mel–Tb(III) a linear correlation was established between the integrated CL intensity and melatonin concent. - Highlights: • Chemiluminescence (CL) of melatonin (Mel) oxidation by reactive species of oxygen and nitrogen. • Tb(III) and Dy(III) ions as sensitizers of a melatonin oxidation process. • New CL method for determination of melatonin in pharmaceutical preparations based on CL of Fe(II)/Fe(III)–H{sub 2}O{sub 2}–Mel–Tb(III) system.

  18. Investigation of extra power loss sharing among photovoltaic inverters caused by reactive power management in distribution networks

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

    2014-01-01

    load and power loss on the feeders and individual inverters. Simplified energy loss evaluation is carried out here by using analytical average loss modeling of 2-level full bridge inverter coupled with network load flow analysis simulating one month period. The study shows that whatever Q control......Grid-connected photovoltaic (PV) inverters tailored with reactive power management feature can support the grid voltage especially when the voltage fluctuates near its admissible limits. Although Q control allows reducing the grid voltage elevation along the distribution feeder, it brings extra...... is selected, extra power loss is not a substantial amount to take into consideration. Similarly, loss difference among the inverters located at the various points is negligible....

  19. Radial distribution of power starting from the reactivity using nodal schemes of second and third order

    International Nuclear Information System (INIS)

    Delfin L, A.; Alonso V, G.; Valle G, E. del

    2003-01-01

    In this work two nodal schemes of finite element are presented, one of second and the other of third order of accurate that allow to determine the radial distribution of power starting from the corresponding reactivities.The schemes here developed were obtained taking as starting point the equation developed by Driscoll et al, the one which is based on the diffusion approach of 1-1/2 energy groups. This equation relates the power fraction of an assemble with their reactivity and with the power fractions and reactivities of the assemblies that its surround it. Driscoll and collaborators they solve in form approximate such equation supposing that the reactivity of each assemble it is but a lineal function of the burnt one of the fuel. The spatial approach carries out it with the classic technique of finite differences centered in mesh. Nevertheless that the algebraic system to which its arrive it can be solved without more considerations introduce some additional suppositions and adjustment parameters that it allows them to predict results comparable to those contributed by three dimensions analysis and this way to reduce the one obtained error when its compare their results with those of a production code like CASMO. Also in the two schemes that here are presented the same approaches of Driscoll were used being obtained errors of the one 10% and of 5% for the second schemes and third order respectively for a test case that it was built starting from data of the Cycle 1 of the Unit 1 of the Laguna Verde Nucleo electric plant. These errors its were obtained when comparing with a computer program based on the matrix response method. It is sought to have this way a quick and efficient tool for the multicycle analysis in the fuel management. However, this model presents problems in the appropriate prediction of the average burnt of the nucleus and of the burnt one by lot. (Author)

  20. Reduction of DC-link Capacitor in Case of Cascade Multilevel Converters by means of Reactive Power Control

    DEFF Research Database (Denmark)

    Gohil, Ghanshyamsinh Vijaysinh; Wang, Huai; Liserre, Marco

    2014-01-01

    A method to selectively control the amount of dc link voltage ripple by processing desired reactive power by a DC/DC converter in isolated AC/DC or AC/DC/AC system is proposed. The concept can reduce the dc link capacitors used for balancing the input and output power and thereby limiting...... the voltage ripple. It allows the use of smaller dc link capacitor and hence a longer lifetime and at the same time high power density and low cost can be achieved. The isolated DC/DC converter is controlled to process the desired reactive power in addition to the active power. The control system to achieve...

  1. A new algorithm for optimum voltage and reactive power control for minimizing transmission lines losses

    International Nuclear Information System (INIS)

    Ghoudjehbaklou, H.; Danai, B.

    2001-01-01

    Reactive power dispatch for voltage profile modification has been of interest to power utilities. Usually local bus voltages can be altered by changing generator voltages, reactive shunts, ULTC transformers and SVCs. Determination of optimum values for control parameters, however, is not simple for modern power system networks. Heuristic and rather intelligent algorithms have to be sought. In this paper a new algorithm is proposed that is based on a variant of a genetic algorithm combined with simulated annealing updates. In this algorithm a fuzzy multi-objective a approach is used for the fitness function of the genetic algorithm. This fuzzy multi-objective function can efficiently modify the voltage profile in order to minimize transmission lines losses, thus reducing the operating costs. The reason for such a combination is to utilize the best characteristics of each method and overcome their deficiencies. The proposed algorithm is much faster than the classical genetic algorithm and cna be easily integrated into existing power utilities software. The proposed algorithm is tested on an actual system model of 1284 buses, 799 lines, 1175 fixed and ULTC transformers, 86 generators, 181 controllable shunts and 425 loads

  2. Recursive Pyramid Algorithm-Based Discrete Wavelet Transform for Reactive Power Measurement in Smart Meters

    Directory of Open Access Journals (Sweden)

    Mahin K. Atiq

    2013-09-01

    Full Text Available Measurement of the active, reactive, and apparent power is one of the most fundamental tasks of smart meters in energy systems. Recently, a number of studies have employed the discrete wavelet transform (DWT for power measurement in smart meters. The most common way to implement DWT is the pyramid algorithm; however, this is not feasible for practical DWT computation because it requires either a log N cascaded filter or O (N word size memory storage for an input signal of the N-point. Both solutions are too expensive for practical applications of smart meters. It is proposed that the recursive pyramid algorithm is more suitable for smart meter implementation because it requires only word size storage of L × Log (N-L, where L is the length of filter. We also investigated the effect of varying different system parameters, such as the sampling rate, dc offset, phase offset, linearity error in current and voltage sensors, analog to digital converter resolution, and number of harmonics in a non-sinusoidal system, on the reactive energy measurement using DWT. The error analysis is depicted in the form of the absolute difference between the measured and the true value of the reactive energy.

  3. A Hybrid Estimator for Active/Reactive Power Control of Single-Phase Distributed Generation Systems with Energy Storage

    DEFF Research Database (Denmark)

    Pahlevani, Majid; Eren, Suzan; Guerrero, Josep M.

    2016-01-01

    This paper presents a new active/reactive power closed-loop control system for a hybrid renewable energy generation system used for single-phase residential/commercial applications. The proposed active/reactive control method includes a hybrid estimator, which is able to quickly and accurately es...

  4. Adaptive reactive power control of PV power plants for improved power transfer capability under ultra-weak grid conditions

    DEFF Research Database (Denmark)

    Yang, Dongsheng; Wang, Xiongfei; Liu, Fangcheng

    2017-01-01

    The Photovoltaic (PV) power plants are usually deployed in remote areas with the high solar irradiance, and their power transfer capabilities can be greatly limited by the large impedance of long-distance transmission lines. This paper investigates first the power transfer limit of the PV power p...

  5. A Statistical Method for Aggregated Wind Power Plants to Provide Secondary Frequency Control

    DEFF Research Database (Denmark)

    Hu, Junjie; Ziras, Charalampos; Bindner, Henrik W.

    2017-01-01

    curtailment for aggregated wind power plants providing secondary frequency control (SFC) to the power system. By using historical SFC signals and wind speed data, we calculate metrics for the reserve provision error as a function of the scheduled wind power. We show that wind curtailment can be significantly......The increasing penetration of wind power brings significant challenges to power system operators due to the wind’s inherent uncertainty and variability. Traditionally, power plants and more recently demand response have been used to balance the power system. However, the use of wind power...... as a balancing-power source has also been investigated, especially for wind power dominated power systems such as Denmark. The main drawback is that wind power must be curtailed by setting a lower operating point, in order to offer upward regulation. We propose a statistical approach to reduce wind power...

  6. Transaction of long-term power purchasing contract by independent power providers in wholesale and retail competitive system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Hoon [Korea Energy Economics Institute, Euiwang (Korea)

    1998-12-01

    In general, the restructuring starts with separation and division of power sector from the existing monopolist as the cases of Thailand and Malaysia. When the power provider is separated and divided, it becomes an independent power provider. The existing regional electricity provider carries out the supplying function to end-users buying electricity from several separated and divided providers. Therefore, the existing regional electricity providers give up the power generation business but become a demand monopolist in wholesale market. The competition system capable of applying during the separation period is the Generation Pool. With the Generation Pool, it is able to promote competition of power generation sector effectively and there is no need to have an extra step such as long-term power purchasing contract. In fact, Latin America and Chile have been managed the power market for more than 10 years with the competition system by the Generation Pool. 9 refs.

  7. Reactivity control in HTR power plants with respect to passive safety system. Summary

    Energy Technology Data Exchange (ETDEWEB)

    Barnert, H; Kugeler, K [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Sicherheitsforschung und Reaktortechnik

    1996-12-01

    The R and D and Demonstration of the High Temperature Reactor (HTR) is described in overview. The HTR-MODULE power plant, as the most advanced concept, is taken for the description of the reactivity control in general. The idea of the ``modularization of the core`` of the HTR has been developed as the answer on the experiences of the core melt accident at Three Miles Island. The HTR module has two shutdown systems: The ``6 rods``-system for hot shutdown at the ``18 small absorber pebbles units`` - system for cold shutdown. With respect to the definition of ``Passive Systems`` of IAEA-TECDOC-626 the total reactivity control system of the HTR-MODULE is a passive system of category D, because it is an emergency reactor shutdown system based on gravity driven rods, and devices, activated by fail-safe trip logic. But reactivity control of the HTR does not only consist of these engineered safety system but does have a self-acting stabilization by the negative temperature coefficient of the reactivity, being rather effective in reactivity control. Examples from computer calculations are presented, and, in addition, experimental results from the ``Stuck Rod Experiment`` at the AVR reactor in Juelich. On the basis of this the proposal is made that ``self-acting stabilization as a quality of the function`` should be discussed as a new category in addition to the active and passive engineered safety systems, structures and components of IAEA-TECDOC-626. The requirements for a future ``catastrophe-free`` nuclear technology are presented. In the appendix the 7th amendment of the atomic energy act of the Federal Republic of Germany, effective 28 July 94, is given. (author).

  8. Method and apparatus to provide power conversion with high power factor

    Energy Technology Data Exchange (ETDEWEB)

    Perreault, David J.; Lim, Seungbum; Otten, David M.

    2017-05-23

    A power converter circuit rectifies a line voltage and applies the rectified voltage to a stack of capacitors. Voltages on the capacitors are coupled to a plurality of regulating converters to be converted to regulated output signals. The regulated output signals are combined and converted to a desired DC output voltage of the power converter. Input currents of the regulating converters are modulated in a manner that enhances the power factor of the power converter.

  9. Implementation of New Reactivity Measurement System and New Reactor Noise Analysis Equipment in a VVER-440 Nuclear Power Plant

    Science.gov (United States)

    Vegh, János; Kiss, Sándor; Lipcsei, Sándor; Horvath, Csaba; Pos, István; Kiss, Gábor

    2010-10-01

    The paper deals with two recently developed, high-precision nuclear measurement systems installed at the VVER-440 units of the Hungarian Paks NPP. Both developments were motivated by the reactor power increase to 108%, and by the planned plant service time extension. The first part describes the RMR start-up reactivity measurement system with advanced services. High-precision picoampere meters were installed at each reactor unit and measured ionization chamber current signals are handled by a portable computer providing data acquisition and online reactivity calculation service. Detailed offline evaluation and analysis of reactor start-up measurements can be performed on the portable unit, too. The second part of the paper describes a new reactor noise diagnostics system using state-of-the-art data acquisition hardware and signal processing methods. Details of the new reactor noise measurement evaluation software are also outlined. Noise diagnostics at Paks NPP is a standard tool for core anomaly detection and for long-term noise trend monitoring. Regular application of these systems is illustrated by real plant data, e.g., results of standard reactivity measurements during a reactor startup session are given. Noise applications are also illustrated by real plant measurements; results of core anomaly detection are presented.

  10. Coordination of voltage and reactive power control in the extra high voltage substations based on the example of solutions applied in the national power system

    Directory of Open Access Journals (Sweden)

    Dariusz Kołodziej

    2012-06-01

    Full Text Available This paper presents examples of coordination between automatic voltage and reactive power control systems (ARST covering adjacent and strongly related extra high voltage substations. Included are conclusions resulting from the use of these solutions. The Institute of Power Engineering, Gdańsk Division has developed and deployed ARST systems in the national power system for a dozen or so years.

  11. Photovoltaic Hosting Capacity of Feeders with Reactive Power Control and Tap Changers

    Energy Technology Data Exchange (ETDEWEB)

    Ceylan, Oğuzhan; Paudyal, Sumit; Bhattarai, Bishnu P.; Myers, Kurt S.

    2017-06-01

    This paper proposes an algorithm to determine photovoltaic (PV) hosting capacity of power distribution networks as a function of number of PV injection nodes, reactive power support from the PVs, and the sub-station load tap changers (LTCs). In the proposed method, several minute by minute simulations are run based on randomly chosen PV injection nodes, daily PV output profiles, and daily load profiles from a pool of high-resolution realistic data set. The simulation setup is built using OpenDSS and MATLAB. The performance of the proposed method is investigated in the IEEE 123-node distribution feeder for multiple scenarios. The case studies are performed particularly for one, two, five and ten PV injection nodes, and looking at the maximum voltage deviations. Case studies show that the PV hosting capacity of the 123-node feeder greatly differs with the number of PV injection nodes. We have also observed that the PV hosting capacity increases with reactive power support and higher tap position of sub-station LTC.

  12. Voltage stability in low voltage microgrids in aspects of active and reactive power demand

    Directory of Open Access Journals (Sweden)

    Parol Mirosław

    2016-03-01

    Full Text Available Low voltage microgrids are autonomous subsystems, in which generation, storage and power and electrical energy consumption appear. In the paper the main attention has been paid to the voltage stability issue in low voltage microgrid for different variants of its operation. In the introduction a notion of microgrid has been presented, and also the issue of influence of active and reactive power balance on node voltage level has been described. Then description of voltage stability issue has been presented. The conditions of voltage stability and indicators used to determine voltage stability margin in the microgrid have been described. Description of the low voltage test microgrid, as well as research methodology along with definition of considered variants of its operation have been presented further. The results of exemplary calculations carried out for the daily changes in node load of the active and reactive power, i.e. the voltage and the voltage stability margin indexes in nodes have been presented. Furthermore, the changes of voltage stability margin indexes depending on the variant of the microgrid operation have been presented. Summary and formulation of conclusions related to the issue of voltage stability in microgrids have been included at the end of the paper.

  13. Loss of Excitation Detection in Doubly Fed Induction Generator by Voltage and Reactive Power Rate

    Directory of Open Access Journals (Sweden)

    M. J. Abbasi

    2016-12-01

    Full Text Available The doubly fed induction generator (DFIG is one of the most popular technologies used in wind power systems. With the growing use of DFIGs and increasing power system dependence on them in recent years, protecting of these generators against internal faults is more considered. Loss of excitation (LOE event is among the most frequent failures in electric generators. However, LOE detection studies heretofore were usually confined to synchronous generators. Common LOE detection methods are based on impedance trajectory which makes the system slow and also prone to interpret a stable power swing (SPS as a LOE fault. This paper suggests a new method to detect the LOE based on the measured variables from the DFIG terminal. In this combined method for LOE detection, the rate of change of both the terminal voltage and the output reactive power are utilized and for SPS detection, the fast Fourier transform (FFT analysis of the output instantaneous active power has been used. The performance of the proposed method was evaluated using Matlab/Simulink interface for various power capacities and operating conditions. The results proved the method's quickness, simplicity and security.

  14. Study on offshore wind farm integration mode and reactive power compensation

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Xiaoyan; Hong, Lijun; Fu, Yang [Shanghai Univ. of Electrical Power (China). Power and Automation Engineering Dept.

    2013-07-01

    Two typical offshore wind farm grid-connected modes are introduced and dynamic characteristics under their modes are compared from the simulation by PSS/E. The result shows that offshore wind farm with VSC-HVDC has better dynamic characteristics on fault isolation, reactive power compensation, and fault ride through ability. In addition, STATCOM has been applied to the offshore wind farm, the simulation results indicates that it can improve the bus voltage stability in fault and maintain the voltage level under a small perturbation.

  15. Optimization-based reactive power control in HVDC-connected wind power plants

    OpenAIRE

    Schönleber, Kevin; Collados Rodríguez, Carlos; Teixeira Pinto, Rodrigo; Ratés Palau, Sergi; Gomis Bellmunt, Oriol

    2017-01-01

    One application of high–voltage dc (HVdc) systems is the connection of remotely located offshore wind power plants (WPPs). In these systems, the offshore WPP grid and the synchronous main grid operate in decoupled mode, and the onshore HVdc converter fulfills the grid code requirements of the main grid. Thus, the offshore grid can be operated independently during normal conditions by the offshore HVdc converter and the connected wind turbines. In general, it is well known that optimized react...

  16. Active and reactive power support of MV distribution systems using battery energy storage

    DEFF Research Database (Denmark)

    Wang, Jiawei; Hashemi Toghroljerdi, Seyedmostafa; You, Shi

    2017-01-01

    shaving and voltage support service from the perspective of Distribution System Operators (DSOs). An active power support algorithm is implemented and the effects of various load profiles as well as different Photovoltaic (PV) penetration scenarios on the operation of BESS and the optimal BESS converter......Adoption of Battery Energy Storage Systems (BESSs) for provision of grid services is increasing. This paper investigates the applications of BESS for the grid upgrade deferral and voltage support of Medium Voltage (MV) distribution systems. A BESS is modelled in Matlab/Simulink to perform peak load...... size for peak load shaving are investigated. The BESS annual lifetime degradation is also estimated using a rainflow counting algorithm. A reactive power support algorithm embedded with Q-U droop control is proposed in order to reduce the voltage drop in a part of 10 kV distribution network of Nordhavn...

  17. Effects of Radial Reflector Composition on Core Reactivity and Peak Power

    International Nuclear Information System (INIS)

    Park, Sang Yoon; Lee, Kyung Hoon; Song, Jae Seung

    2007-10-01

    The effects of radial SA-240 alloy shroud on core reactivity and peak power are evaluated. The existence of radial SA-240 alloy shroud makes reflector water volume decrease, so the thermal absorption cross section of radial reflector is lower than without SA-240 alloy shroud case. Finally, the cycle length is increased from 788 EFPD to 845 EFPD and the peak power is decreased from 1.66 to 1.49. In the case of without SA-240 alloy shroud, a new core loading pattern search has been performed. For the guarantee of the same equivalent cycle length of with SA-240 alloy shroud case, the enrichment of U-235 should be increased from 4.22 w/o to 4.68 w/o. The nuclear key safety parameters of new core loading pattern have been calculated and recorded for the future

  18. Effects of Radial Reflector Composition on Core Reactivity and Peak Power

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Yoon; Lee, Kyung Hoon; Song, Jae Seung

    2007-10-15

    The effects of radial SA-240 alloy shroud on core reactivity and peak power are evaluated. The existence of radial SA-240 alloy shroud makes reflector water volume decrease, so the thermal absorption cross section of radial reflector is lower than without SA-240 alloy shroud case. Finally, the cycle length is increased from 788 EFPD to 845 EFPD and the peak power is decreased from 1.66 to 1.49. In the case of without SA-240 alloy shroud, a new core loading pattern search has been performed. For the guarantee of the same equivalent cycle length of with SA-240 alloy shroud case, the enrichment of U-235 should be increased from 4.22 w/o to 4.68 w/o. The nuclear key safety parameters of new core loading pattern have been calculated and recorded for the future.

  19. Estimation of power feedback parameters of the IBR-2M reactor by square wave reactivity

    International Nuclear Information System (INIS)

    Pepelyshev, Yu.N.; Popov, A.K.; Sumkhuu, D.

    2016-01-01

    Parameters of the IBR-2M reactor power feedback (PFB) are estimated based on the analysis of power transients caused by deliberate square wave reactivity when the pulsed reactor operates in the self-regulation mode. The PFB of the IBR-2M is described by three linear first-order differential equations. Two components of the PFB are responsible for the negative feedback and one, for the positive. The overall feedback is negative, i.e., it has a stabilizing effect for the operation of the reactor. The slowest negative component of the PFB is probably caused by heating of the fuel. Periodically repeated in the process of exploitation, estimation of the PFB parameters is one of the methods to ensure safety operation of the reactor. [ru

  20. Comparisons of PRD [power-reactivity-decrements] components for various EBR-II configurations

    International Nuclear Information System (INIS)

    Meneghetti, D.; Kucera, D.A.

    1986-01-01

    Comparison of detailed calculations of contributions by region and component of the power-reactivity-decrements (PRD) for four differing loading configurations of the Experimental Breeder Reactor-II (EBR-II) are given. The linear components and Doppler components are calculated. The non-linear (primarily subassembly bowing) components are deduced by differences relative to measured total PRD values. Variations in linear components range from about 10% to as much as about 100% depending upon the component. The deduced non-linear components differ both in magnitude and sign as functions of reactor power. Effects of differing assumptions of the nature of the fuel-to-clad interactions upon the PRD components are also calculated

  1. Solar pv fed stand-alone excitation system of a synchronous machine for reactive power generation

    Science.gov (United States)

    Sudhakar, N.; Jain, Siddhartha; Jyotheeswara Reddy, K.

    2017-11-01

    This paper presents a model of a stand-alone solar energy conversion system based on synchronous machine working as a synchronous condenser in overexcited state. The proposed model consists of a Synchronous Condenser, a DC/DC boost converter whose output is fed to the field of the SC. The boost converter is supplied by the modelled solar panel and a day time variable irradiance is fed to the panel during the simulation time. The model also has one alternate source of rechargeable batteries for the time when irradiance falls below a threshold value. Also the excess power produced when there is ample irradiance is divided in two parts and one is fed to the boost converter while other is utilized to recharge the batteries. A simulation is done in MATLAB-SIMULINK and the obtained results show the utility of such modelling for supplying reactive power is feasible.

  2. Economic-environmental active and reactive power scheduling of modern distribution systems in presence of wind generations: A distribution market-based approach

    International Nuclear Information System (INIS)

    Samimi, Abouzar; Kazemi, Ahad; Siano, Pierluigi

    2015-01-01

    Highlights: • A new market-based approach is proposed to schedule active and reactive powers. • Multi-component reactive power bidding structures for DERs is introduced. • A new economical/environmental operational scheduling method is proposed. • At distribution level, a reactive power market is developed in presence of DERs. - Abstract: Distribution System Operator (DSO) is responsible for active and reactive power scheduling in a distribution system. DSO purchases its active and reactive power requirements from Distributed Energy Resources (DERs) as well as the wholesale electricity market. In this paper, a new economical/environmental operational scheduling method based on sequential day-ahead active and reactive power markets at distribution level is proposed to dispatch active and reactive powers in distribution systems with high penetration of DERs. In the proposed model, after day-ahead active power market was cleared the participants submit their reactive power bids and then the reactive power market will be settled. At distribution level, developing a Var market, in which DERs like synchronous machine-based Distributed Generation (DG) units and Wind Turbines (WTs) could offer their reactive power prices, DERs are motivated to actively participate in the Volt/VAr Control (VVC) problem. To achieve this purpose, based on the capability curves of considered DERs, innovative multi-component reactive power bidding structures for DERs are introduced. Moreover, the effect of reactive power market clearing on the active power scheduling is explicitly considered into the proposed model by rescheduling of active power by usage of energy-balance service bids. On the other hand, environmental concerns that arise from the operation of fossil fuel fired electric generators are included in the proposed model by employing CO_2 emission penalty cost. The suggested reactive power market is cleared through a mixed-integer nonlinear optimization program. The

  3. Nash equilibrium strategies of generating companies (Gencos) in the simultaneous operation of active and reactive power market, with considering voltage stability margin

    International Nuclear Information System (INIS)

    Soleymani, S.

    2013-01-01

    Highlights: ► We model the behavior of Gencos in the active and reactive power markets. ► Genco’s strategy is modeled as a bi-level optimization problem. ► The ISO’s market clearing model is modified with applying generator APFs. ► Good forecast of Genco’s information will increase the accuracy of proposed method. ► Obtained profit of Gencos depend on their bidding strategy. - Abstract: As Gencos are responsible for providing active and reactive power generation, they should devise good bidding strategies for energy and reactive power market. The paper describes a method for analyzing the competition among transmission-constrained Gencos with incomplete information. The proposed methodology employs the Supply Function Equilibrium (SFE) for modeling a Genco’s bidding strategy in energy market and uses Expected Payment Function (EPF) to construct a bidding framework in the reactive power market. The problem of finding the optimum strategy of Gencos is modeled as a bi-level optimization problem, where the upper sub-problem represents individual Genco’s payoff and the lower sub-problem solves the ISO’s market clearing problem. The ISO’s market clearing model is modified with applying generator Active Participation Factors to improve the voltage stability margin. The IEEE 39 bus test system is used to verify the effectiveness of the proposed method.

  4. Inherent Safety Feature of Hybrid Low Power Research Reactor during Reactivity Induced Accident

    Energy Technology Data Exchange (ETDEWEB)

    Kim, DongHyun; Yum, Soo Been; Hong, Sung Teak; Lim, In-Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Hybrid low power research reactor(H-LPRR) is the new design concept of low power research reactor for critical facility as well as education and training. In the case of typical low power research reactor, the purposes of utilization are the experiments for education of nuclear engineering students, Neutron Activation Analysis(NAA) and radio-isotope production for research purpose. H-LPRR is a light-water cooled and moderated research reactor that uses rod-type LEU UO{sub 2} fuels same as those for commercial power plants. The maximum core thermal power is 70kW and, the core is placed in the bottom of open pool. There are 1 control rod and 2 shutdown rods in the core. It is designed to cool the core by natural convection, retain negative feedback coefficient for entire fuel periods and operate for 20 years without refueling. Inherent safety in H-LPRR is achieved by passive design features such as negative temperature feedback coefficient and core cooling by natural convection during normal and emergency conditions. The purpose of this study is to find out that the inherent safety characteristics of H-LPRR is able to control the power and protect the reactor from the RIA(Reactivity induced accident). RIA analysis was performed to investigate the inherent safety feature of H-LPRR. As a result, it was found that the reactor controls its power without fuel damage in the event and that the reactor remains safe states inherently. Therefore, it is believed that high degree of safety inheres in H-LPRR.

  5. 78 FR 63177 - Order on Voluntary Remand and Clarifying Policy on Filing of Reactive Power Service Rate...

    Science.gov (United States)

    2013-10-23

    ... the obligation to follow a voltage schedule.'' \\19\\ The Commission distinguished Hot Spring Power Co..., to explore the mechanics of public utilities filing reactive power rate schedules for which there is...'' jurisdictional service and, accordingly, must be filed for Commission review); Sulphur Springs Valley Elec. Coop...

  6. Reactive Power Management in Islanded Microgrid – Proportional Power Sharing in Hierarchical Droop Control

    DEFF Research Database (Denmark)

    Milczarek, Adam; Malinowski, Mariusz; Guerrero, Josep M.

    2015-01-01

    A microgrid (MG) is a local energy system consisting a number of energy sources (e.g. wind turbine or solar panels among others), energy storage units and loads that operate connected to the main electrical grid or autonomously. MGs provide flexibility, reduce the main electricity grid dependence...

  7. 18 CFR 2.22 - Pricing policy for transmission services provided under the Federal Power Act.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Pricing policy for... INTERPRETATIONS Statements of General Policy and Interpretations Under the Federal Power Act § 2.22 Pricing policy... Policy Statement on its pricing policy for transmission services provided under the Federal Power Act...

  8. Fuzzy-TLBO optimal reactive power control variables planning for energy loss minimization

    International Nuclear Information System (INIS)

    Moghadam, Ahmad; Seifi, Ali Reza

    2014-01-01

    Highlights: • A new approach to the problem of optimal reactive power control variables planning is proposed. • The energy loss minimization problem has been formulated by modeling the load of system as a Load Duration Curve. • To solving the energy loss problem, the classic methods and the evolutionary methods are used. • A new proposed fuzzy teaching–learning based algorithm is applied to energy loss problem. • Simulations are done to show the effectiveness and superiority of the proposed algorithm compared with other methods. - Abstract: This paper offers a new approach to the problem of optimal reactive power control variables planning (ORPVCP). The basic idea is division of Load Duration Curve (LDC) into several time intervals with constant active power demand in each interval and then solving the energy loss minimization (ELM) problem to obtain an optimal initial set of control variables of the system so that is valid for all time intervals and can be used as an initial operating condition of the system. In this paper, the ELM problem has been solved by the linear programming (LP) and fuzzy linear programming (Fuzzy-LP) and evolutionary algorithms i.e. MHBMO and TLBO and the results are compared with the proposed Fuzzy-TLBO method. In the proposed method both objective function and constraints are evaluated by membership functions. The inequality constraints are embedded into the fitness function by the membership function of the fuzzy decision and the problem is modeled by fuzzy set theory. The proposed Fuzzy-TLBO method is performed on the IEEE 30 bus test system by considering two different LDC; and it is shown that using this method has further minimized objective function than original TLBO and other optimization techniques and confirms its potential to solve the ORPCVP problem with considering ELM as the objective function

  9. A Fast Reactive Power Optimization in Distribution Network Based on Large Random Matrix Theory and Data Analysis

    Directory of Open Access Journals (Sweden)

    Wanxing Sheng

    2016-05-01

    Full Text Available In this paper, a reactive power optimization method based on historical data is investigated to solve the dynamic reactive power optimization problem in distribution network. In order to reflect the variation of loads, network loads are represented in a form of random matrix. Load similarity (LS is defined to measure the degree of similarity between the loads in different days and the calculation method of the load similarity of load random matrix (LRM is presented. By calculating the load similarity between the forecasting random matrix and the random matrix of historical load, the historical reactive power optimization dispatching scheme that most matches the forecasting load can be found for reactive power control usage. The differences of daily load curves between working days and weekends in different seasons are considered in the proposed method. The proposed method is tested on a standard 14 nodes distribution network with three different types of load. The computational result demonstrates that the proposed method for reactive power optimization is fast, feasible and effective in distribution network.

  10. High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation

    Science.gov (United States)

    Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

    2017-08-01

    Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system.

  11. BN600 reactivity definition

    International Nuclear Information System (INIS)

    Zheltyshev, V.; Ivanov, A.

    2000-01-01

    Since 1980, the fast BN600 reactor with sodium coolant has been operated at Beloyarsk Nuclear Power Plant. The periodic monitoring of the reactivity modifications should be implemented in compliance with the standards and regulations applied in nuclear power engineering. The reactivity measurements are carried out in order to confirm the basic neutronic features of a BN600 reactor. The reactivity measurements are aimed to justify that nuclear safety is provided in course of the in-reactor installation of the experimental core components. Two reactivity meters are to be used on BN600 operation: 1. Digital on-line reactivity calculated under stationary reactor operation on power (approximation of the point-wise kinetics is applied). 2. Second reactivity meter used to define the reactor control rod operating components efficiency under reactor startup and take account of the changing efficiency of the sensor, however, this is more time-consumptive than the on-line reactivity meter. The application of two reactivity meters allows for the monitoring of the reactor reactivity under every operating mode. (authors)

  12. New Enhanced Artificial Bee Colony (JA-ABC5 Algorithm with Application for Reactive Power Optimization

    Directory of Open Access Journals (Sweden)

    Noorazliza Sulaiman

    2015-01-01

    Full Text Available The standard artificial bee colony (ABC algorithm involves exploration and exploitation processes which need to be balanced for enhanced performance. This paper proposes a new modified ABC algorithm named JA-ABC5 to enhance convergence speed and improve the ability to reach the global optimum by balancing exploration and exploitation processes. New stages have been proposed at the earlier stages of the algorithm to increase the exploitation process. Besides that, modified mutation equations have also been introduced in the employed and onlooker-bees phases to balance the two processes. The performance of JA-ABC5 has been analyzed on 27 commonly used benchmark functions and tested to optimize the reactive power optimization problem. The performance results have clearly shown that the newly proposed algorithm has outperformed other compared algorithms in terms of convergence speed and global optimum achievement.

  13. New enhanced artificial bee colony (JA-ABC5) algorithm with application for reactive power optimization.

    Science.gov (United States)

    Sulaiman, Noorazliza; Mohamad-Saleh, Junita; Abro, Abdul Ghani

    2015-01-01

    The standard artificial bee colony (ABC) algorithm involves exploration and exploitation processes which need to be balanced for enhanced performance. This paper proposes a new modified ABC algorithm named JA-ABC5 to enhance convergence speed and improve the ability to reach the global optimum by balancing exploration and exploitation processes. New stages have been proposed at the earlier stages of the algorithm to increase the exploitation process. Besides that, modified mutation equations have also been introduced in the employed and onlooker-bees phases to balance the two processes. The performance of JA-ABC5 has been analyzed on 27 commonly used benchmark functions and tested to optimize the reactive power optimization problem. The performance results have clearly shown that the newly proposed algorithm has outperformed other compared algorithms in terms of convergence speed and global optimum achievement.

  14. Comparing concentrating solar and nuclear power as baseload providers using the example of South Africa

    International Nuclear Information System (INIS)

    Pfenninger, Stefan; Keirstead, James

    2015-01-01

    Despite the increasing importance of variable renewable power generation, baseload, that is stable and predictable power generators, remain the backbone of many countries’ power systems. We here compare CSP (concentrating solar power) and nuclear power as baseload electricity providers for the case of South Africa, which is adding significant new generation capacity, has an abundant solar resource, but also one existing and additional planned nuclear power plants. Both of these technologies are considered baseload-capable with sufficient available fuel (sunlight or fissible material) to provide large amounts of nearly emissions-free electricity. We find that under a range of technological learning assumptions, CSP compares favorably against nuclear on costs in the period to 2030, and has lower investment and environmental risks. The results suggest that while nuclear power may be an important low-emissions power technology in regions with little sun, in the case of South Africa, CSP could be capable of providing a stable baseload supply at lower cost than nuclear power, and may have other non-cost benefits. - Highlights: • We compare nuclear and CSP (concentrating solar power) as baseload generators. • CSP could be competitive with nuclear by 2030 on providing baseload. • CSP plants producing above baseload when possible are more competitive. • On environmental and investment risks, CSP compares favorably. • Both options may have a role in different parts of the world

  15. Comprehensive Cost Minimization in Distribution Networks Using Segmented-time Feeder Reconfiguration and Reactive Power Control of Distributed Generators

    DEFF Research Database (Denmark)

    Chen, Shuheng; Hu, Weihao; Chen, Zhe

    2016-01-01

    In this paper, an efficient methodology is proposed to deal with segmented-time reconfiguration problem of distribution networks coupled with segmented-time reactive power control of distributed generators. The target is to find the optimal dispatching schedule of all controllable switches...... and distributed generators’ reactive powers in order to minimize comprehensive cost. Corresponding constraints, including voltage profile, maximum allowable daily switching operation numbers (MADSON), reactive power limits, and so on, are considered. The strategy of grouping branches is used to simplify...... (FAHPSO) is implemented in VC++ 6.0 program language. A modified version of the typical 70-node distribution network and several real distribution networks are used to test the performance of the proposed method. Numerical results show that the proposed methodology is an efficient method for comprehensive...

  16. Dependence of RF power on the content and configuration of hydrogen in amorphous hydrogenated silicon by reactive sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Imura, T; Ushita, K; Mogi, K; Hiraki, A [Osaka Univ., Suita (Japan). Faculty of Engineering

    1981-06-01

    Infrared absorption spectra at stretching bands of Si-H were investigated in hydrogenated amorphous silicon fabricated by reactive sputtering in the atmosphere of Ar and H/sub 2/ (10 mole%) at various input rf powers in the range from 0.8 to 3.8 W/cm/sup 2/. Hydrogen content mainly due to the configuration of Si=H/sub 2/ in the film increased with the decreasing rf power, as the deposition rate was decreased. On the other hand, the quantity of the monohydride (Si-H) configuration depended less on the power. Attachment of hydrogen molecules onto the fresh and reactive surface of silicon deposited successively was proposed for possible process of hydrogen incusion into amorphous silicon resulting in Si=H/sub 2/ configuration. The photoconductivity increased as the input power became higher, when the deposition rate also increased linearly with the power.

  17. A process for providing positive primary control power by wind turbines

    Science.gov (United States)

    Marschner, V.; Michael, J.; Liersch, J.

    2014-12-01

    Due to the increasing share of wind energy in electricity generation, wind turbines have to fulfil additional requirements in the context of grid integration. The paper examines to which extent wind turbines can provide positive control power following the related grid code. The additional power has to be obtained from the rotating flywheel mass of the wind turbine's rotor. A simple physical model is developed that allows to draw conclusions about appropriate concepts by means of a dynamic simulation of the variables rotational speed, torque, power output and rotor power. The paper discusses scenarios to provide control power. The supply of control power at partial load is examined in detail using simulations. Under partial load conditions control power can be fed into the grid for a short time. Thereby the rotational speed drops so that aerodynamic efficiency decreases and feed-in power is below the initial value after the control process. In this way an unfavourable situation for the grid control is produced, therefore the paper proposes a modified partial load condition with a higher rotational speed. By providing primary control power the rotor is delayed to the optimum rotational speed so that more rotational energy can be fed in and fed-in power can be increased persistently. However, as the rotor does not operate at optimum speed, a small amount of the energy yield is lost. Finally, the paper shows that a wind farm can combine these two concepts: A part of the wind turbines work under modified partial load conditions can compensate the decrease of power of the wind turbines working under partial load conditions. Therefore the requested control power is provided and afterwards the original value of power is maintained.

  18. Mix of power system flexibility means providing 50 % wind power penetration in the Danish power system in 2030

    DEFF Research Database (Denmark)

    Nørgård, Per Bromand; Lund, H.; Mathiesen, B.V.

    2008-01-01

    Time series simulations of an example of a realistic modified energy system in Denmark 2030, assuming no internal power transmission bottlenecks, indicates that it is both technical possible and economic feasible to maintain the energy balance on hourly basis, even with a wind power penetration...

  19. National survey provides average power quality profiles for different customer groups

    International Nuclear Information System (INIS)

    Hughes, B.; Chan, J.

    1996-01-01

    A three year survey, beginning in 1991, was conducted by the Canadian Electrical Association to study the levels of power quality that exist in Canada, and to determine ways to increase utility expertise in making power quality measurements. Twenty-two utilities across Canada were involved, with a total of 550 sites being monitored, including residential and commercial customers. Power disturbances, power outages and power quality were recorded for each site. To create a group average power quality plot, the transient disturbance activity for each site was normalized to a per channel, per month basis and then divided into a grid. Results showed that the average power quality provided by Canadian utilities was very good. Almost all the electrical disturbance within a customer premises were created and stayed within those premises. Disturbances were generally beyond utility control. Utilities could, however, reduce the amount of time the steady-state voltage exceeds the CSA normal voltage upper limit. 5 figs

  20. A Modular Cascaded Multilevel Inverter Based Shunt Hybrid Active Power Filter for Selective Harmonic and Reactive Power Compensation Under Distorted/Unbalanced Grid Voltage Conditions

    Directory of Open Access Journals (Sweden)

    T. Demirdelen

    2016-10-01

    Full Text Available In recent years, shunt hybrid active power filters are being increasingly considered as a viable alternative to both passive filters and active power filters for compensating harmonics. In literature, their applications are restricted to balanced systems and low voltage applications and therefore not for industrial applications. This paper investigates the performance of a modular cascaded multilevel inverter based Shunt Hybrid Active Power Filter (SHAPF for reactive power compensation and selective harmonics elimination under distorted/unbalanced grid voltage conditions in medium voltage levels. In the proposed control method, reactive power compensation is achieved successfully with a perceptible amount and the performance results of harmonic compensation are satisfactory. Theoretical analysis and simulation results are obtained from an actual industrial network model in PSCAD. The simulation results are presented for a proposed system in order to demonstrate that the harmonic compensation performance meets the IEEE-519 standard.

  1. Solving multiobjective optimal reactive power dispatch using modified NSGA-II

    Energy Technology Data Exchange (ETDEWEB)

    Jeyadevi, S.; Baskar, S.; Babulal, C.K.; Willjuice Iruthayarajan, M. [Department of Electrical and Electronics Engineering, Thiagarajar College of Engineering, Madurai, Tamilnadu 625 015 (India)

    2011-02-15

    This paper addresses an application of modified NSGA-II (MNSGA-II) by incorporating controlled elitism and dynamic crowding distance (DCD) strategies in NSGA-II to multiobjective optimal reactive power dispatch (ORPD) problem by minimizing real power loss and maximizing the system voltage stability. To validate the Pareto-front obtained using MNSGA-II, reference Pareto-front is generated using multiple runs of single objective optimization with weighted sum of objectives. For simulation purposes, IEEE 30 and IEEE 118 bus test systems are considered. The performance of MNSGA-II, NSGA-II and multiobjective particle swarm optimization (MOPSO) approaches are compared with respect to multiobjective performance measures. TOPSIS technique is applied on obtained non-dominated solutions to determine best compromise solution (BCS). Karush-Kuhn-Tucker (KKT) conditions are also applied on the obtained non-dominated solutions to substantiate a claim on optimality. Simulation results are quite promising and the MNSGA-II performs better than NSGA-II in maintaining diversity and authenticates its potential to solve multiobjective ORPD effectively. (author)

  2. Real And Reactive Power Saving In Three Phase Induction Machine Using Star-Delta Switching Schemes

    Directory of Open Access Journals (Sweden)

    Ramesh Daravath

    2017-04-01

    Full Text Available Induction machines are the most commonly used industrial drives for variety of applications. It has been estimated that induction motors consumes approximately 50 of all the electric energy generated. Further in the area of renewable energy sources such as wind or bio-mass energy induction machines have been found suitable for functioning as generators. In this context it may be mentioned that a star-delta switching is common for the starting of three-phase induction motor. Now it is proposed to use this star-delta switching for energy conservation of induction machines i.e. at times of reduced loads the machine switched back to star connection. Using a three-phase 400 V 50 Hz 4-pole induction machine it has been demonstrated that the star-delta switching of stator winding of three-phase induction machine motor generator operations reconnected in star at suitable reduced loads with a switching arrangement can result in improved efficiency and power factor as compared to a fixed delta or star connection. The predetermined values along with the experimental results have also been presented in this report. A simulation program has been developed for the predetermination of performance of the three-phase induction machine using exact equivalent circuit. A case study on a 250 kW 400 V 4-pole three-phase induction machine operated with different load cycles reveals the significant real and reactive power savings that could be obtained in the present proposal.

  3. National supply of reactivity control rods for Embalse nuclear power plant (CNE)

    International Nuclear Information System (INIS)

    Biondo, C.D.; Carloni, J.G.; Aba, J.A.

    1987-01-01

    The manufacture and supply on industrial scale of reactivity control rods for CNE (Embalse nuclear power plant) were developed by the National Atomic Energy Commission (CNEA) together with the private industry, as part of a program aimed to the substitution of imported supplies used in the operation of power plants by materials manufactured in Argentina. So far, the control rods were imported from Canada. In this work, the different development stages performed by CNEA and CONUAR S.A. are described, leading to the supply of a set of 21 cobalt rods to be included in a reactor of CNE in order to qualify this component. Among the main activities performed, the following stand out: specifications development, particularly those concerning to cobalt cores, evaluation of design documentation and elaboration of bidding conditions and a plan of manufacture and control. According to the results obtained during the service and the post-irradiation measurements, the design will be reviewed in order to undertake new manufacturing plans. (Author)

  4. Systems and methods for providing power to a load based upon a control strategy

    Science.gov (United States)

    Perisic, Milun; Kajouke, Lateef A; Ransom, Ray M

    2013-12-24

    Systems and methods are provided for an electrical system. The electrical system includes a load, an interface configured to receive a voltage from a voltage source, and a controller configured to receive the voltage from the voltage source through the interface and to provide a voltage and current to the load. Wherein, when the controller is in a constant voltage mode, the controller provides a constant voltage to the load, when the controller is in a constant current mode, the controller provides a constant current to the load, and when the controller is in a constant power mode, the controller provides a constant power to the load.

  5. Demand response strategy management with active and reactive power incentive in the smart grid: a two-level optimization approach

    Directory of Open Access Journals (Sweden)

    Ryuto Shigenobu

    2017-05-01

    Full Text Available High penetration of distributed generators (DGs using renewable energy sources (RESs is raising some important issues in the operation of modern po­wer system. The output power of RESs fluctuates very steeply, and that include uncertainty with weather conditions. This situation causes voltage deviation and reverse power flow. Several methods have been proposed for solving these problems. Fundamentally, these methods involve reactive power control for voltage deviation and/or the installation of large battery energy storage system (BESS at the interconnection point for reverse power flow. In order to reduce the installation cost of static var compensator (SVC, Distribution Company (DisCo gives reactive power incentive to the cooperating customers. On the other hand, photovoltaic (PV generator, energy storage and electric vehicle (EV are introduced in customer side with the aim of achieving zero net energy homes (ZEHs. This paper proposes not only reactive power control but also active power flow control using house BESS and EV. Moreover, incentive method is proposed to promote participation of customers in the control operation. Demand response (DR system is verified with several DR menu. To create profit for both side of DisCo and customer, two level optimization approach is executed in this research. Mathematical modeling of price elasticity and detailed simulations are executed by case study. The effectiveness of the proposed incentive menu is demonstrated by using heuristic optimization method.

  6. Thermal Performance and Reliability Analysis of Single-Phase PV Inverters with Reactive Power Injection Outside Feed-In Operating Hours

    DEFF Research Database (Denmark)

    Anurag, Anup; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    Reactive power support by photovoltaic (PV) systems is of increasingly interest, when compared to the conventional reactive power compensation devices. PV inverters can exchange reactive power with the utility grid in a decentralized manner even outside feed-in operation, especially at nights when...... there is no solar irradiance. However, reactive power injection causes additional power losses in the switching components leading to a temperature rise in the devices. Thus, this paper analyses the impact of reactive power injection by PV inverters outside feed-in operation on the thermal performance...... of their power switching components. A thermal analysis based on the mission profile (i.e., solar irradiance and ambient temperature) has been incorporated, so as to determine the additional temperature rise in the components induced by the operation outside feed-in hours. An analytical lifetime model has been...

  7. Customized power quality service provided by converter interfaced microgrids — Voltage harmonics as a study case

    DEFF Research Database (Denmark)

    Meng, Lexuan; Chaudhary, Sanjay K.; Guerrero, Josep M.

    2017-01-01

    Customers may have different power quality requirements, thus, the economic operational strategy can try to provide them with distinctive quality levels as customized service. An optimization based method is proposed in this paper to realize this functionality, offering the possibility...

  8. An Integral Model to Provide Reactive and Proactive Services in an Academic CSIRT Based on Business Intelligence

    Directory of Open Access Journals (Sweden)

    Walter Fuertes

    2017-11-01

    Full Text Available Cyber-attacks have increased in severity and complexity. That requires, that the CERT/CSIRT research and develops new security tools. Therefore, our study focuses on the design of an integral model based on Business Intelligence (BI, which provides reactive and proactive services in a CSIRT, in order to alert and reduce any suspicious or malicious activity on information systems and data networks. To achieve this purpose, a solution has been assembled, that generates information stores, being compiled from a continuous network transmission of several internal and external sources of an organization. However, it contemplates a data warehouse, which is focused like a correlator of logs, being formed by the information of feeds with diverse formats. Furthermore, it analyzed attack detection and port scanning, obtained from sensors such as Snort and Passive Vulnerability Scanner, which are stored in a database, where the logs have been generated by the systems. With such inputs, we designed and implemented BI systems using the phases of the Ralph Kimball methodology, ETL and OLAP processes. In addition, a software application has been implemented using the SCRUM methodology, which allowed to link the obtained logs to the BI system for visualization in dynamic dashboards, with the purpose of generating early alerts and constructing complex queries using the user interface through objects structures. The results demonstrate, that this solution has generated early warnings based on the level of criticality and level of sensitivity of malware and vulnerabilities as well as monitoring efficiency, increasing the level of security of member institutions.

  9. K 4R - Knowledge to the Power of RESTful, Resourceful and Reactive Rules

    Science.gov (United States)

    Amador, Ricardo

    The Web of today clearly answers questions of the form "What is the representation of ...?". The Semantic Web (SW) of tomorrow aims at answering questions of the form "What is the meaning of ...?". It is our stance that in order to realize the full potential of the original concept proposed by Tim Berners-Lee et al. (in Scientific American, May 2001), the SW must also answer, in a meaningful way, questions of a dynamic and active nature, like "What to do if ...?" or "What to do when ...?". Moreover, SW questions of the form "What to do ...?" must be expressed and answered in a declarative, compositional and language agnostic way. It is our (hypo)thesis that formally established concepts, viz. the Web's REST architectural style, declarative SW representation of resources based on Description Logics (e.g., OWL-DL), and Reactive Rules (e.g., "on Event if Condition do Action" -ECA- rules), provide the proper theoretical foundations to achieve this goal. This paper describes our current research proposal, K 4R (pronounced, with an Italian flavor, "Che fare?"), towards achieving a declarative model for expressing (re)active behavior in and for the SW.

  10. Optimal stochastic reactive power scheduling in a microgrid considering voltage droop scheme of DGs and uncertainty of wind farms

    International Nuclear Information System (INIS)

    Khorramdel, Benyamin; Raoofat, Mahdi

    2012-01-01

    Distributed Generators (DGs) in a microgrid may operate in three different reactive power control strategies, including PV, PQ and voltage droop schemes. This paper proposes a new stochastic programming approach for reactive power scheduling of a microgrid, considering the uncertainty of wind farms. The proposed algorithm firstly finds the expected optimal operating point of each DG in V-Q plane while the wind speed is a probabilistic variable. A multi-objective function with goals of loss minimization, reactive power reserve maximization and voltage security margin maximization is optimized using a four-stage multi-objective nonlinear programming. Then, using Monte Carlo simulation enhanced by scenario reduction technique, the proposed algorithm simulates actual condition and finds optimal operating strategy of DGs. Also, if any DGs are scheduled to operate in voltage droop scheme, the optimum droop is determined. Also, in the second part of the research, to enhance the optimality of the results, PSO algorithm is used for the multi-objective optimization problem. Numerical examples on IEEE 34-bus test system including two wind turbines are studied. The results show the benefits of voltage droop scheme for mitigating the impacts of the uncertainty of wind. Also, the results show preference of PSO method in the proposed approach. -- Highlights: ► Reactive power scheduling in a microgrid considering loss and voltage security. ► Stochastic nature of wind farms affects reactive power scheduling and is considered. ► Advantages of using the voltage droop characteristics of DGs in voltage security are shown. ► Power loss, voltage security and VAR reserve are three goals of a multi-objective optimization. ► Monte Carlo method with scenario reduction is used to determine optimal control strategy of DGs.

  11. Coupling/Tradeoff Analysis and Novel Containment Control for Reactive Power, Output Voltage in Islanded Micro-Grid

    DEFF Research Database (Denmark)

    Han, Renke; Meng, Lexuan; Guerrero, Josep M.

    2016-01-01

    Based on the hierarchical control structure in islanded Micro-Grid (MG) systems, the coupling/tradeoff effects in different control levels are analyzed in details. In the primary level, analyses of the coupling effects among droop control gains, line impedance differences, output reactive power...

  12. Optimization Based Shunt APF Controller to Mitigate Reactive Power, Burden of Neutral Conductor, Current Harmonics and Improve cosɸ

    Directory of Open Access Journals (Sweden)

    P. Anjana

    2017-03-01

    Full Text Available This paper presents a Modified Gravitational Search Algorithm (MGSA to improve the performance of PI controller in varying load condition. The proposed approach is capable of mitigating reactive power, neutral current, source current THD and significant improvement in power factor nearly unity (0.997. The DC link voltage across the capacitor is controlled by PI controller which is deciding the performance of shunt APF. Hence, the robust optimization technique based integral time square error (ITSE with consideration of weight factor (α & β, maximum overshoot ((|(∆_Ve ̅〖(n〗_max | and setling time t_s-t_0, is providing the optimum solution of Kp & Ki. The robustness of proposed objective function and algorithm compared with GSA based three other error criterion techniques. The efficiency of the proposed controller has been tested over nonlinear and unbalance loading condition. The performance of ITSE based MGSA-PI controller is batter then other three error criterion techniques. The values of THD are below the mark of 5% specified in IEEE-519 standard.

  13. Investigation of the behavior of a three phase grid-connected photovoltaic system to control active and reactive power

    Energy Technology Data Exchange (ETDEWEB)

    Tsengenes, Georgios; Adamidis, Georgios [Department of Electrical Engineering and Computer Engineering, Democritus University of Thrace, University Campus Kimmeria, 67100 Xanthi (Greece)

    2011-01-15

    In this paper, a photovoltaic (PV) system, with maximum power point tracking (MPPT), connected to a three phase grid is presented. The connection of photovoltaic system on the grid takes place in one stage using voltage source inverter (VSI). For a better utilization of the photovoltaic system, the control strategy applied is based on p-q theory. According to this strategy during sunlight the system sends active power to the grid and at the same time compensates the reactive power of the load. In case there is no sunlight (during the night for instance), the inverter only compensates the reactive power of the load. In this paper the use of p-q theory to supply the grid with active power and compensate the reactive power of the load is investigated. The advantage of this control strategy is that the photovoltaic system is operated the whole day. Furthermore, the p-q theory uses simple algebraic calculations without demanding the use of PLL to synchronize the inverter with the grid. (author)

  14. An optimal reactive power control strategy for a DFIG-based wind farm to damp the sub-synchronous oscillation of a power system

    DEFF Research Database (Denmark)

    Zhao, Bin; Li, Hui; Wang, Mingyu

    2014-01-01

    This study presents the auxiliary damping control with the reactive power loop on the rotor-side converter of doubly-fed induction generator (DFIG)-based wind farms to depress the sub-synchronous resonance oscillations in nearby turbogenerators. These generators are connected to a series capaciti...

  15. Rutile TiO2 thin films grown by reactive high power impulse magnetron sputtering

    International Nuclear Information System (INIS)

    Agnarsson, B.; Magnus, F.; Tryggvason, T.K.; Ingason, A.S.; Leosson, K.; Olafsson, S.; Gudmundsson, J.T.

    2013-01-01

    Thin TiO 2 films were grown on Si(001) substrates by reactive dc magnetron sputtering (dcMS) and high power impulse magnetron sputtering (HiPIMS) at temperatures ranging from 300 to 700 °C. Optical and structural properties of films were compared both before and after post-annealing using scanning electron microscopy, low angle X-ray reflection (XRR), grazing incidence X-ray diffractometry and spectroscopic ellipsometry. Both dcMS- and HiPIMS-grown films reveal polycrystalline rutile TiO 2 , even prior to post-annealing. The HiPIMS-grown films exhibit significantly larger grains compared to that of dcMC-grown films, approaching 100% of the film thickness for films grown at 700 °C. In addition, the XRR surface roughness of HiPIMS-grown films was significantly lower than that of dcMS-grown films over the whole temperature range 300–700 °C. Dispersion curves could only be obtained for the HiPIMS-grown films, which were shown to have a refractive index in the range of 2.7–2.85 at 500 nm. The results show that thin, rutile TiO 2 films, with high refractive index, can be obtained by HiPIMS at relatively low growth temperatures, without post-annealing. Furthermore, these films are smoother and show better optical characteristics than their dcMS-grown counterparts. - Highlights: • We demonstrate growth of rutile TiO 2 on Si (111) by high power impulse magnetron sputtering. • The films exhibit significantly larger grains than dc magnetron sputtered films • TiO 2 films with high refractive index are obtained without post-growth annealing

  16. Single-point reactive power control method on voltage rise mitigation in residential networks with high PV penetration

    DEFF Research Database (Denmark)

    Hasheminamin, Maryam; Agelidis, Vassilios; Ahmadi, Abdollah

    2018-01-01

    Voltage rise (VR) due to reverse power flow is an important obstacle for high integration of Photovoltaic (PV) into residential networks. This paper introduces and elaborates a novel methodology of an index-based single-point-reactive power-control (SPRPC) methodology to mitigate voltage rise by ...... system with high r/x ratio. Efficacy, effectiveness and cost study of SPRPC is compared to droop control to evaluate its advantages.......Voltage rise (VR) due to reverse power flow is an important obstacle for high integration of Photovoltaic (PV) into residential networks. This paper introduces and elaborates a novel methodology of an index-based single-point-reactive power-control (SPRPC) methodology to mitigate voltage rise...... by absorbing adequate reactive power from one selected point. The proposed index utilizes short circuit analysis to select the best point to apply this Volt/Var control method. SPRPC is supported technically and financially by distribution network operator that makes it cost effective, simple and efficient...

  17. Using hydropower to complement wind energy: a hybrid system to provide firm power

    Energy Technology Data Exchange (ETDEWEB)

    Jaramillo, O.A.; Borja, M.A.; Huacuz, J.M. [Instituto de Investigaciones Electricas, Morelos (Mexico). Energias No Convencionales

    2004-09-01

    This paper presents a theoretical study of how wind power can be complemented by hydropower. A conceptual framework is provided for a hybrid power station that produces constant power output without the intermittent fluctuations inherent when using wind power. Two hypothetical facilities are considered as case studies. One of them is a hydropower plant located on the ''Presidente Benito Juarez'' dam in Jalapa del Marques, Oaxaca, Mexico. The other hypothetical facility is a wind farm located near ''La Venta's', an area in Juchitan, Oaxaca, Mexico. The wind-hydro-power system is a combined wind and hydro power plant in a region that is rich in both resources. The model shows that the hybrid plant could provide close to 20 MW of firm power to the electrical distribution system. On a techno-economic basis, we obtain the levelized production cost of the hybrid system. Taking into account two different discount rates of 7% and 10%, figures for levelized production cost are developed. (author)

  18. Opportunities for ice storage to provide ancillary services to power grids incorporating wind turbine generation

    Science.gov (United States)

    Finley, Christopher

    Power generation using wind turbines increases the electrical system balancing, regulation and ramp rate requirements due to the minute to minute variability in wind speed and the difficulty in accurately forecasting wind speeds. The addition of thermal energy storage, such as ice storage, to a building's space cooling equipment increases the operational flexibility of the equipment by allowing the owner to choose when the chiller is run. The ability of the building owner to increase the power demand from the chiller (e.g. make ice) or to decrease the power demand (e.g. melt ice) to provide electrical system ancillary services was evaluated.

  19. Process stabilization by peak current regulation in reactive high-power impulse magnetron sputtering of hafnium nitride

    International Nuclear Information System (INIS)

    Shimizu, T; Villamayor, M; Helmersson, U; Lundin, D

    2016-01-01

    A simple and cost effective approach to stabilize the sputtering process in the transition zone during reactive high-power impulse magnetron sputtering (HiPIMS) is proposed. The method is based on real-time monitoring and control of the discharge current waveforms. To stabilize the process conditions at a given set point, a feedback control system was implemented that automatically regulates the pulse frequency, and thereby the average sputtering power, to maintain a constant maximum discharge current. In the present study, the variation of the pulse current waveforms over a wide range of reactive gas flows and pulse frequencies during a reactive HiPIMS process of Hf-N in an Ar–N 2 atmosphere illustrates that the discharge current waveform is a an excellent indicator of the process conditions. Activating the reactive HiPIMS peak current regulation, stable process conditions were maintained when varying the N 2 flow from 2.1 to 3.5 sccm by an automatic adjustment of the pulse frequency from 600 Hz to 1150 Hz and consequently an increase of the average power from 110 to 270 W. Hf–N films deposited using peak current regulation exhibited a stable stoichiometry, a nearly constant power-normalized deposition rate, and a polycrystalline cubic phase Hf-N with (1 1 1)-preferred orientation over the entire reactive gas flow range investigated. The physical reasons for the change in the current pulse waveform for different process conditions are discussed in some detail. (paper)

  20. Computation, measurement and analysis of the reactivity-to-power-transfer-function for the sodium cooled nuclear power plant KNK I

    International Nuclear Information System (INIS)

    Hoppe, P.; Mitzel, F.

    1977-02-01

    The Reactivity-to-Power-Transfer-Function for the sodium cooled nuclear power plant KNK I (Kompakte Natriumgekuehlte Kernenergieanlage) has been measured and compared with theoretical results. The measurements have been performed with the help of pseudostochastic reactivity perturbations. The transfer function has been determined by computing the auto- and cross-power-spectral-densities for the reactivity- and neutron flux signals. The agreement between the experimental and theoretical transfer function could be improved by adjusting the reactivity coefficients. The applications of these measurements with respect to reactor diagnosis and malfunction detection are discussed. For this purpose the accuracy of the measured transfer function is of great importance. Therefore an extensive error analysis has been performed. It turned out, that the inherent instability of the reactor without control system and the feedback by the primary coolant system were the reasons for comparatively big systematical errors. The conditions have been derived under which these types of errors can be considerably reduced. The conclusions can also be applied to analogical measurements at fast sodium cooled reactors. Because of their inherent stability the systematical errors will be reduced. (orig.) [de

  1. Determination of the excess of reactivity in a nuclear configuration and its influence on the power level

    International Nuclear Information System (INIS)

    Zuniga, Agustin; Tapia, Jose

    2014-01-01

    This work presents experimental results which show that the critical position of a given nuclear configuration changes with the reactor power (expressed by the current measurement). Thus, if the current is 0.6 x 10 -11 A (1 W), then the critical position is, BC1 = 0.0 % while 0.6 x 10 -9 A (100 W), BC1= 46.5 %. The difference is apparent because under a current of 10 -10 A, the reactivity is not significant. Therefore, it is recommended that for reactors like the RP-10 with a lot of neutrons at the 'background' level, the excess reactivity must be measured in current as 0.6 x 10 -9 A (100 W) not less. Finally, the excess of reactivity for the N o 42 configuration was determined, which was 3032 pcm with uncertainty less than 1 %. (authors).

  2. [Effects of Reactive Jump Training in Handball Players Regarding Jump Height and Power Development in the Triceps Surae Muscle].

    Science.gov (United States)

    Rensing, N; Westermann, A; Möller, D; von Piekartz, H

    2015-12-01

    Studies have shown changes in the technical and physical demands in modern handball. The game has increased considerably in speed, power and dynamics. Jump training has, therefore, become ever more important in the training of the athletes. These developments contribute to the fact that handball is now one of the most injury-prone types of sport, with the lower extremities being most frequently affected. Reactive jump training is not only used in training by now, but also increasingly in injury prevention. The aim of this study was to investigate the effectiveness of reactive jump training with handball players. 21 regional league handball players were randomly divided into an intervention group (n = 12) and a control group (n = 9). The intervention group completed a six-week reactive jump training programme while the control group went through a non-specific training programme. Jump height (squat and counter movement jump), isokinetic and isometric maximum power as well as muscle activity served as measuring parameters. A comparison of the intervention and control groups revealed that the reactive jump training led to significant improvements in jump height. The isometric and isokinetic maximum power measurements and the electromyographic activities of the triceps surae muscle demonstrated an improvement in the values within the intervention group. However, this improvement was not significant compared with the control group. Likewise both jumps correlated with the muscle activity of the soleus muscle as shown by electromyography. A moderate correlation was noticed between the isokinetic maximum power measurement and the electromyographic activity of the soleus and gastrocnemius medialis muscles. Furthermore, the correlations of the isometric and isokinetic maximum power meas-urements resulted in a strong correlation coefficient. This study revealed a significant increase in jump height after reactive jump training. There was no significant difference in

  3. Transient voltage control of a DFIG-based wind power plant for suppressing overvoltage using a reactive current reduction loop

    Directory of Open Access Journals (Sweden)

    Geon Park

    2016-01-01

    Full Text Available This paper proposes a transient voltage control scheme of a doubly fed induction generator (DFIG-based wind power plant (WPP using a reactive current reduction loop to suppress the overvoltage at a point of interconnection (POI and DFIG terminal after a fault clearance. The change of terminal voltage of a DFIG is monitored at every predefined time period to detect the fault clearance. If the voltage change exceeds a set value, then the reactive current reduction loop reduces the reactive current reference in the DFIG controller using the step function. The reactive current injection of DFIGs in a WPP is rapidly reduced, and a WPP can rapidly suppress the overvoltage at a fault clearance because the reactive current reference is reduced. Using an electromagnetic transients program–released version (EMTP–RV simulator, the performance of the proposed scheme was validated for a model system comprising 20 units of a 5-MW DFIG considering various scenarios, such as fault and wind conditions. Test results show that the proposed scheme enables a WPP to suppress the overvoltage at the POI and DFIG terminal within a short time under grid fault conditions.

  4. Plug-in hybrid electric vehicles as regulating power providers. Case studies of Sweden and Germany

    International Nuclear Information System (INIS)

    Andersson, S.-L.; Goeransson, L.; Karlsson, S.; Johnsson, F.; Elofsson, A.K.; Galus, M.D.; Andersson, G.

    2010-01-01

    This study investigates plug-in hybrid electric vehicles (PHEVs) as providers of regulating power in the form of primary, secondary and tertiary frequency control. Previous studies have shown that PHEVs could generate substantial profits while providing ancillary services. This study investigates under what conditions PHEVs can generate revenues using actual market data, i.e. prices and activations of regulating power, from Sweden and Germany from four months in 2008. PHEV market participation is modelled for individual vehicles in a fleet subject to a simulated movement pattern. Costs for infrastructure and vehicle-to-grid equipment are not included in the analysis. The simulation results indicate that maximum average profits generated on the German markets are in the range 30-80 EUR per vehicle and month whereas the Swedish regulating power markets give no profit. In addition, an analysis is performed to identify strengths, weaknesses, opportunities, and threats (SWOT) of PHEVs as regulating power providers. Based on the simulation results and the SWOT analysis, characteristics for an ideal regulating power market for PHEVs are presented. (author)

  5. Containment and Consensus-based Distributed Coordination Control for Voltage Bound and Reactive Power Sharing in AC Microgrid

    DEFF Research Database (Denmark)

    Han, Renke; Meng, Lexuan; Ferrari-Trecate, Giancarlo

    2017-01-01

    This paper offers a highly flexible and reliable control strategy to achieve voltage bounded regulation and accurate reactive power sharing coordinately in AC Micro-Grids. A containment and consensus-based distributed coordination controller is proposed, by which each output voltage magnitude can...... be bounded within a reasonable range and the accurate reactive power sharing among distributed generators can be also achieved. Combined with the two proposed controllers and electrical part of the AC Micro-Grid, a small signal model is fully developed to analyze the sensitivity of different control...... parameters. The effectiveness of the proposed controller in case of load variation, communication failure, plug-and-play capability are verified by the experimental setup as an islanded Micro-Grid....

  6. A Data-Driven Stochastic Reactive Power Optimization Considering Uncertainties in Active Distribution Networks and Decomposition Method

    DEFF Research Database (Denmark)

    Ding, Tao; Yang, Qingrun; Yang, Yongheng

    2018-01-01

    To address the uncertain output of distributed generators (DGs) for reactive power optimization in active distribution networks, the stochastic programming model is widely used. The model is employed to find an optimal control strategy with minimum expected network loss while satisfying all......, in this paper, a data-driven modeling approach is introduced to assume that the probability distribution from the historical data is uncertain within a confidence set. Furthermore, a data-driven stochastic programming model is formulated as a two-stage problem, where the first-stage variables find the optimal...... control for discrete reactive power compensation equipment under the worst probability distribution of the second stage recourse. The second-stage variables are adjusted to uncertain probability distribution. In particular, this two-stage problem has a special structure so that the second-stage problem...

  7. Autonomous Control of Current and Voltage Controlled DG Interface Inverters for Reactive Power Sharing and Harmonics Compensation in Islanded Microgrids

    DEFF Research Database (Denmark)

    Mousazadeh, Seyyed Yousef; Jalilain, Alireza; Savaghebi, Mehdi

    2018-01-01

    In microgrids, Voltage Source Inverters (VSIs) interfacing Distributed Generation (DG) units can be operated in Voltage or Current Controlled Modes (VCM/CCM). In this paper, a coordinated control of CCM and VCM units for reactive power sharing and voltage harmonics compensation is proposed....... This decentralized control scheme is based on the local measurement of signals. In this way, the need for communication links is removed which results in a simpler and more reliable structure compared to the communication based control structures. To be more exact, the VCM units contribute to harmonics compensation....... Experimental and simulation studies show that the harmonics compensation is achieved by using only local measurements in presence of virtual admittance/impedance schemes of CCM/VCM units. Furthermore, it is demonstrated that the reactive power sharing among the CCM and VCM units is obtained based...

  8. Robots provide valuable tools for waste processing at Millstone Nuclear Power Station

    International Nuclear Information System (INIS)

    Miles, K.; Volpe, K.

    1997-01-01

    The Millstone nuclear power station has begun an aggressive program to use robotics, which when properly used minimizes operating costs and exposure to personnel. This article describes several new ways of using existing robotic equipment to speed up work processes and provide solutions to difficult problems. The moisture separator pit and liquid radwaste are discussed

  9. A Powered Lower Limb Orthosis for Providing Legged Mobility in Paraplegic Individuals

    OpenAIRE

    Quintero, Hugo A.; Farris, Ryan J.; Hartigan, Clare; Clesson, Ismari; Goldfarb, Michael

    2011-01-01

    This paper presents preliminary results on the development of a powered lower limb orthosis intended to provide legged mobility (with the use of a stability aid, such as forearm crutches) to paraplegic individuals. The orthosis contains electric motors at both hip and both knee joints, which in conjunction with ankle-foot orthoses, provides appropriate joint kinematics for legged locomotion. The paper describes the orthosis and the nature of the controller that enables the SCI patient to comm...

  10. Analysis of static safety of power systems: a study about contingencies selection criteria in the reactive subproblem; Analise de seguranca estatica de sistemas de potencia: um estudo sobre criterios de selecao de contingencias no subproblema reativo

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Jose Vicente Canto dos

    1993-12-01

    The main objective of static safety's analysis in power systems is the determination of the level of gravity of the different contingencies that can occur in a system. Habitually, static safety's analysis is divided in two parts: selection and analysis of contingencies. In this work, they are studied several criteria of selection of applicable contingencies to the sub-problem reactive and are introduced comparisons among results provided by different criteria. They are also studied several forms of evaluation of the impact caused by contingencies on the power systems reactive profile.

  11. Analysis of static safety of power systems: a study about contingencies selection criteria in the reactive subproblem; Analise de seguranca estatica de sistemas de potencia: um estudo sobre criterios de selecao de contingencias no subproblema reativo

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Jose Vicente Canto dos

    1993-12-01

    The main objective of static safety's analysis in power systems is the determination of the level of gravity of the different contingencies that can occur in a system. Habitually, static safety's analysis is divided in two parts: selection and analysis of contingencies. In this work, they are studied several criteria of selection of applicable contingencies to the sub-problem reactive and are introduced comparisons among results provided by different criteria. They are also studied several forms of evaluation of the impact caused by contingencies on the power systems reactive profile.

  12. Monitoring temperature reactivity coefficient by noise method in a NPP at full power

    International Nuclear Information System (INIS)

    Aguilar, O.; Por, G.

    1987-04-01

    A new method based on noise measurement was used to estimate the temperature reactivity coefficient of the PAKS-2 reactor during the entire fuel cycle. Based on the measurements it is possible to measure the dependence of reactivity coefficient on boron concentration. Good agreement was found between the results obtained by the new method and by the conventional ones. Based on this method a new equipment can be develop which assures permanent measurements during operation. (author)

  13. Sensitivity analysis for reactivity and power density investigations in nuclear reactors

    International Nuclear Information System (INIS)

    Naguib, K.; Morcos, H.N.; Sallam, O.H.; Abdelsamei, SH.

    1993-01-01

    Sensitivity analysis theory based on the variational functional approaches was applied to evaluate sensitivities of eigenvalues and power densities due to variation of the absorber concentration in the reactor core. The practical usefulness of this method is illustrated by considering test cases. The result indicates that this method is as accurate as those obtained from direct calculations, yet it provides an economical means in saving computational time since it requires fewer calculations. The SARC-1/2 code have been written in Fortran-77 to solve this problem.3 tab. 1 fig

  14. In-core power sharing and fuel requirement study for a decommissioning Boiling Water Reactor using the linear reactivity model

    International Nuclear Information System (INIS)

    Chen, Chung-Yuan; Tung, Wu-Hsiung; Yaur, Shung-Jung; Kuo, Weng-Sheng

    2014-01-01

    Highlights: • Linear reactivity model (LRM) was modified and applied to Boiling Water Reactor. • The power sharing and fuel requirement study of the last cycle and two cycles before decommissioning was implemented. • The loading pattern design concept for the cycles before decommissioning is carried out. - Abstract: A study of in-core power sharing and fuel requirement for a decommissioning BWR (Boiling Water Reactor) was carried out using the linear reactivity model (LRM). The power sharing of each fuel batch was taken as an independent variable, and the related parameters were set and modified to simulate actual cases. Optimizations of the last cycle and two cycles before decommissioning were both implemented; in the last-one-cycle optimization, a single cycle optimization was carried out with different upper limits of fuel batch power, whereas, in the two-cycle optimization, two cycles were optimized with different cycle lengths, along with two different optimization approaches which are the simultaneous optimization of two cycles (MO) and two successive single-cycle optimizations (SO). The results of the last-one-cycle optimization show that it is better to increase the fresh fuel power and decrease the thrice-burnt fuel power as much as possible. It also shows that relaxing the power limit is good to the fresh fuel requirement which will be reduced under lower power limit. On the other hand, the results of the last-two-cycle (cycle N-1 and N) optimization show that the MO is better than SO, and the power of fresh fuel batch should be decreased in cycle N-1 to save its energy for the next cycle. The results of the single-cycle optimization are found to be the same as that in cycle N of the multi-cycle optimization. Besides that, under the same total energy requirement of two cycles, a long-short distribution of cycle length design can save more fresh fuel

  15. Impact of wind power plant reactive current injection during asymmetrical grid faults

    DEFF Research Database (Denmark)

    Göksu, Ömer; Teodorescu, Remus; Bak, Claus Leth

    2013-01-01

    As more renewable energy sources, especially more wind turbines (WTs) are installed in the power system; grid codes for wind power integration are being generated to sustain stable power system operation with non-synchronous generation. Common to most of the grid codes, wind power plants (WPPs...... faults, is investigated, which was not considered in the wind power impact studies before....

  16. A Powered Lower Limb Orthosis for Providing Legged Mobility in Paraplegic Individuals.

    Science.gov (United States)

    Quintero, Hugo A; Farris, Ryan J; Hartigan, Clare; Clesson, Ismari; Goldfarb, Michael

    2011-01-01

    This paper presents preliminary results on the development of a powered lower limb orthosis intended to provide legged mobility (with the use of a stability aid, such as forearm crutches) to paraplegic individuals. The orthosis contains electric motors at both hip and both knee joints, which in conjunction with ankle-foot orthoses, provides appropriate joint kinematics for legged locomotion. The paper describes the orthosis and the nature of the controller that enables the SCI patient to command the device, and presents data from preliminary trials that indicate the efficacy of the orthosis and controller in providing legged mobility.

  17. Utilization of underground coal gasification to provide electric power and emerging nations

    International Nuclear Information System (INIS)

    Boysen, J.E.; Beaver, F.W.; Schmit, C.R.; Daly, D.J.; Groenewold, G.H.

    1992-01-01

    Underground coal gasification (UCG) is a process conceived over a hundred years ago and used successfully, since the 1940s, to generate low-Btu gas for electric power production. The process is applicable to many coal resources that cannot, for a variety of reasons, be economically produced. While UCG cannot compete economically with conventional oil gas, and coal reserves, emerging nations requiring electric power for development of an industrial infrastructure may provide the niche market that is necessary for the commercial development of UCG. Recent UCG field testing, conducted in the United States, demonstrated that UCG could be successfully conducted without adverse environmental impact. This testing also resulted in increased understanding of the interactions between the UCG process and the local hydrogeological environment. With this knowledge, the probability of successful commercial UCG development can be increased by selecting a UCG site with hydrogeologically and economically favorable properties. And approach for commercial UCG development for producing electric power in emerging nations is presented

  18. Structural and optical properties of zirconia thin films deposited by reactive high-power impulse magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xiaoli; Jin, Jie [Tianjin University, School of Electronic Information Engineering, Tianjin (China); Cheng, Jui-Ching, E-mail: juiching@ntut.edu.tw [Chang-Gung University, Department of Electronics, Taoyuan, Taiwan (China); Lee, Jyh-Wei [Ming Chi University of Technology, College of Materials Engineering, New Taipei City, Taiwan (China); Wu, Kuo-Hong [Chang-Gung University, Department of Electronics, Taoyuan, Taiwan (China); Lin, Kuo-Cheng; Tsai, Jung-Ruey [Asia University, Department of Photonics and Communication Engineering, Taichung, Taiwan (China); Liu, Kou-Chen, E-mail: jacobliu@mail.cgu.edu.tw [Chang-Gung University, Department of Electronics, Taoyuan, Taiwan (China)

    2014-11-03

    Zirconia films are deposited by reactive high power impulse magnetron sputtering (HiPIMS) technology on glass and indium-tin-oxide (ITO)/glass substrates. Preparation, microstructure and optical characteristics of the films have been studied. During deposition, the influence of the target power and duty cycle on the peak current–voltage and power density has been observed in oxide mode. Transparent thin films under different oxygen proportions are obtained on the two substrates. Atomic force microscopy measurements showed that the surface roughness of the films was lower by reactive HiPIMS than DC sputtering for all oxygen contents. The transmission and reflectance properties of differently grown zirconia films were also investigated using an ultraviolet–visible spectrophotometer. The optical transmittance of films grown on glass substrates by HiPIMS reached maximum values above 90%, which exceeded that by DC sputtering. The band edge near 5.86 eV shifted to a lower wavelength for zirconia films prepared with oxygen flow rates lower than 4.5 sccm. For the films prepared on ITO/glass substrates, the transmittance and the band gap of zirconia films were limited by ITO films; a maximum average transmittance of 84% was obtained at 4.5 sccm O{sub 2} and the energy band gap was in the range of 3.7–3.8 eV for oxygen flow rates ranging from 3.5 to 5.0 sccm. Finally, the electrical properties of zirconia films have also been discussed. - Highlights: • Zirconia films are deposited by reactive high power impulse magnetron sputtering. • Low roughness films are obtained. • Films show a high transmittance (> 90%). • Films prepared on glass have a band gap of 5.9 eV.

  19. Supervisory Control for Real Time Reactive Power Flow Optimization in Islanded Microgrids

    DEFF Research Database (Denmark)

    Milczarek, Adam; Vasquez, Juan Carlos; Malinowski, Mariusz

    2013-01-01

    -line measurements. Similarly to any process system, MG hierarchical control is divided into three levels. However, an additional control algorithm is required to manage power transmission between sources and loads, maximizing efficiency and minimizing transmission losses. This real-time optimization problem......A microgrid (MG) is a local energy system consisting of a number of energy sources, energy storage units and loads that operate connected to the main electrical grid or autonomously. MGs include wind, solar or other renewable energy sources. MGs provide flexibility, reduce the main electricity grid...... dependence and contribute to change the large centralized production paradigm to local and distributed generation. However, such energy systems require complex management, advanced control and optimization. Interest on MGs hierarchical control has increased due to the availability of cheap on...

  20. Observation of a periodic runaway in the reactive Ar/O2 high power impulse magnetron sputtering discharge

    Directory of Open Access Journals (Sweden)

    Seyedmohammad Shayestehaminzadeh

    2015-11-01

    Full Text Available This paper reports the observation of a periodic runaway of plasma to a higher density for the reactive discharge of the target material (Ti with moderate sputter yield. Variable emission of secondary electrons, for the alternating transition of the target from metal mode to oxide mode, is understood to be the main reason for the runaway occurring periodically. Increasing the pulsing frequency can bring the target back to a metal (or suboxide mode, and eliminate the periodic transition of the target. Therefore, a pulsing frequency interval is defined for the reactive Ar/O2 discharge in order to sustain the plasma in a runaway-free mode without exceeding the maximum power that the magnetron can tolerate.

  1. Detailed neutronic study of the power evolution for the European Sodium Fast Reactor during a positive insertion of reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Facchini, A.; Giusti, V.; Ciolini, R. [Department of Civil and Industrial Engineering (DICI), University of Pisa, Largo Lucio Lazzarino 2, I-56126 Pisa (Italy); Tuček, K.; Thomas, D. [Joint Research Centre, Institute for Energy and Transport (JRC - IET), European Commission, P.O. Box 2, NL-1755 ZG Petten (Netherlands); D' Agata, E., E-mail: elio.dagata@ec.europa.eu [Joint Research Centre, Institute for Energy and Transport (JRC - IET), European Commission, P.O. Box 2, NL-1755 ZG Petten (Netherlands)

    2017-03-15

    Highlights: • This paper studies the effect of an unexpected runway of a control rod in the ESFR. • The power peaked fuel pin within the core was identified. • The increase of the fission power density of the fuel pin has been evaluated. • Radial/axial fission power density of the power peaked fuel pin has been evaluated. - Abstract: The new reactor concepts proposed in the Generation IV International Forum require the development and validation of new components and new materials. Inside the Collaborative Project on the European Sodium Fast Reactor, several accidental scenario have been studied. Nevertheless, none of them coped with mechanical safety assessment of the fuel cladding under accidental conditions. Among the accidental conditions considered, there is the unprotected transient of overpower (UTOP), due to the insertion, at the end of the first fuel cycle, of a positive reactivity into the reactor core as a consequence of the unexpected runaway of one control rod. The goal of the study was the search for a detailed distribution of the fission power, in the radial and axial directions, within the power peaked fuel pin under the above accidental conditions. Results show that after the control rod ejection an increase from 658 W/cm{sup 3} to 894 W/cm{sup 3}, i.e. of some 36%, is expected for the power peaked fuel pin. This information will represent the base to investigate, in a future work, the fuel cladding safety margin.

  2. Structure provided by parents in middle childhood predicts cortisol reactivity in adolescence among the offspring of parents with bipolar disorder and controls.

    Science.gov (United States)

    Ellenbogen, Mark A; Hodgins, Sheilagh

    2009-06-01

    Recent studies suggest that childhood exposure to adversity influences later functioning of the hypothalamic-pituitary-adrenal (HPA) axis. Parenting style in childhood, a putative moderator of adversity, may be important in determining HPA reactivity in adolescence. As part of a prospective, longitudinal study, saliva was collected at awakening and 30 and 60 min later over 2 days among 27 offspring of parents with bipolar disorder (high risk; 16.7+/-1.5 years) and 26 offspring of parents with no mental disorders (low risk; 16.2+/-1.7 years). In addition, 24 of the high risk and 22 of the low risk adolescents completed the "Trier Social Stress Test" (TSST). Parents had rated their parenting style when their offspring were 6-13 years of age. Low levels of structure (i.e. organization and consistency) provided by parents in middle childhood were predictive of an elevated cortisol response following awakening (beta=-0.36; padolescents' mood and behavior. The level of structure provided by parents in childhood predicted independent measures of cortisol reactivity in adolescence, suggesting that parenting style may regulate different aspects of HPA reactivity.

  3. New approaches to provide ride-through for critical loads in electric power distribution systems

    Science.gov (United States)

    Montero-Hernandez, Oscar C.

    2001-07-01

    The extensive use of electronic circuits has enabled modernization, automation, miniaturization, high quality, low cost, and other achievements regarding electric loads in the last decades. However, modern electronic circuits and systems are extremely sensitive to disturbances from the electric power supply. In fact, the rate at which these disturbances happen is considerable as has been documented in recent years. In response to the power quality concerns presented previously, this dissertation is proposing new approaches to provide ride-through for critical loads during voltage disturbances with emphasis on voltage sags. In this dissertation, a new approach based on an AC-DC-AC system is proposed to provide ride-through for critical loads connected in buildings and/or an industrial system. In this approach, a three-phase IGBT inverter with a built in Dc-link voltage regulator is suitably controlled along with static by-pass switches to provide continuous power to critical loads. During a disturbance, the input utility source is disconnected and the power from the inverter is connected to the load. The remaining voltage in the AC supply is converted to DC and compensated before being applied to the inverter and the load. After detecting normal utility conditions, power from the utility is restored to the critical load. In order to achieve an extended ride-through capability a second approach is introduced. In this case, the Dc-link voltage regulator is performed by a DC-DC Buck-Boost converter. This new approach has the capability to mitigate voltage variations below and above the nominal value. In the third approach presented in this dissertation, a three-phase AC to AC boost converter is investigated. This converter provides a boosting action for the utility input voltages, right before they are applied to the load. The proposed Pulse Width Modulation (PWM) control strategy ensures independent control of each phase and compensates for both single-phase or poly

  4. Twenty years of providing information on nuclear power. The experience of EDF

    International Nuclear Information System (INIS)

    Durr, M.; Ansel, P.; Chaussade, J.P.; Haller, P.; Hezard, L.; Hue, L.

    1995-01-01

    In France, the anti-nuclear protest movement became a real problem after 1968, as new sites were sought. Initially, information on nuclear power involved communication by the entities responsible for building the plants. Once Government officials and politicians overcame their initial hesitation, their support, which underscores the continuity of France's energy policy, came to play a major role in the public acceptance of nuclear power. Electricite de France (EDF) then had to master the art of informing and communicating with the public. The change in the parliamentary majority in 1981 did not call into question the nuclear programme, and new plants were commissioned with relative ease. The situation changed dramatically with the Chernobyl disaster. It therefore became vital to establish an efficient structure for crisis communications, and transparency became crucial. The focus shifted from launching new plants to operating existing facilities and restoring public confidence. While not neglecting the general public, the emphasis was on certain strategic segments of the population, notably teachers and health care professionals. Advertising campaigns are today aimed at certain segments of the public, whose opinion could well shift in favour of nuclear power. Lastly, EDF, as power plant operator, has to realize the importance of providing information on nuclear waste. Starting from a strategic policy of informing politicians and senior decision makers, in 1974 EDF began to focus on providing information that would 'educate' the public. This information was issued via technicians who had no specific training in communications techniques. In addition to the need to explain and justify its projects, EDF had to adopt a policy of transparency, and to dispense with the esoteric language of specialists and their preference for secrecy. After Chernobyl, EDF's managers made communications with the 'outside world' an integral part of their jobs. Nuclear information became a

  5. Low carbon technologies as providers of operational flexibility in future power systems

    International Nuclear Information System (INIS)

    Pavić, Ivan; Capuder, Tomislav; Kuzle, Igor

    2016-01-01

    Highlights: • Mixed integer linear programming model for provision of multiple services from EV. • EV energy and reserve services provision effects on power system operation. • Impacts of conventional unit’s decommission on system’s operation and flexibility. • Assessment of power system’s flexibility under different wind generation polices. - Abstract: The paper presents a unit commitment model, based on mixed integer linear programming, capable of assessing the impact of electric vehicles (EV) on provision of ancillary services in power systems with high share of renewable energy sources (RES). The analyses show how role of different conventional units changes with integration of variable and uncertain RES and how introducing a flexible sources on the demand side, in this case EV, impact the traditional provision of spinning/contingency reserve services. In addition, technical constraints of conventional units, such as nuclear, gas or coal, limit the inherit flexibility of the system which results in curtailing clean renewable sources and inefficient operation. Following on that, sensitivity analyses of operational cost and wind curtailment shows which techno-economic constraints impact the flexibility of the high RES systems the most and how integration of more flexible units or decommission of conventional nuclear, coal and gas driven power plants would impact the system’s operation. Finally, two different wind generation polices (wind penalization and wind turbines as reserve providers) have been analysed in terms of operational flexibility through different stages of conventional unit’s decommission and compared with the same analyses when EV were used as reserve providers.

  6. Systems of mechanized and reactive droplets powered by multi-responsive surfactants

    Science.gov (United States)

    Yang, Zhijie; Wei, Jingjing; Sobolev, Yaroslav I.; Grzybowski, Bartosz A.

    2018-01-01

    Although ‘active’ surfactants, which are responsive to individual external stimuli such as temperature, electric or magnetic fields, light, redox processes or chemical agents, are well known, it would be interesting to combine several of these properties within one surfactant species. Such multi-responsive surfactants could provide ways of manipulating individual droplets and possibly assembling them into larger systems of dynamic reactors. Here we describe surfactants based on functionalized nanoparticle dimers that combine all of these and several other characteristics. These surfactants and therefore the droplets that they cover are simultaneously addressable by magnetic, optical and electric fields. As a result, the surfactant-covered droplets can be assembled into various hierarchical structures, including dynamic ones, in which light powers the rapid rotation of the droplets. Such rotating droplets can transfer mechanical torques to their non-nearest neighbours, thus acting like systems of mechanical gears. Furthermore, droplets of different types can be merged by applying electric fields and, owing to interfacial jamming, can form complex, non-spherical, ‘patchy’ structures with different surface regions covered with different surfactants. In systems of droplets that carry different chemicals, combinations of multiple stimuli can be used to control the orientations of the droplets, inter-droplet transport, mixing of contents and, ultimately, sequences of chemical reactions. Overall, the multi-responsive active surfactants that we describe provide an unprecedented level of flexibility with which liquid droplets can be manipulated, assembled and reacted.

  7. Active and reactive power sharing and frequency restoration in a distributed power system consisting of two UPS units

    Energy Technology Data Exchange (ETDEWEB)

    Parlak, Koray Sener; Oezdemir, Mehmet [Dept. of Electrical and Electronic Engineering, Firat University, Elazig, 23119 (Turkey); Aydemir, M. Timur [Dept. of Electrical and Electronic Engineering, Gazi University, Maltepe-Ankara 06570 (Turkey)

    2009-06-15

    A distributed power system consisting of two uninterrupted power supplies (UPS) is investigated in this paper. Parallel operation of the two sources increases the established power rating of the system. One of the sources can supply the system even when the other system is disconnected due to some faults, and this is an important feature. The control algorithm makes sure that the total load is shared between the supplies in accordance with their rated power levels, and the frequency of the supplies are restored to the rated values after the transitions. As the UPSs operate at an optimum power level, losses and faults due to overloading are prevented. The units safely operate without any means of communication between each other. The focus of the work is on the inverter stages of the UPSs. Simulations performed in Matlab Simulink environment have been verified with experimental work via DS1103 controller card. (author)

  8. Coordinated control of active and reactive power of distribution network with distributed PV cluster via model predictive control

    Science.gov (United States)

    Ji, Yu; Sheng, Wanxing; Jin, Wei; Wu, Ming; Liu, Haitao; Chen, Feng

    2018-02-01

    A coordinated optimal control method of active and reactive power of distribution network with distributed PV cluster based on model predictive control is proposed in this paper. The method divides the control process into long-time scale optimal control and short-time scale optimal control with multi-step optimization. The models are transformed into a second-order cone programming problem due to the non-convex and nonlinear of the optimal models which are hard to be solved. An improved IEEE 33-bus distribution network system is used to analyse the feasibility and the effectiveness of the proposed control method

  9. Design of reactive power regulator of synchronous generators by considering grid impedance angle for characteristic index objectives

    DEFF Research Database (Denmark)

    Raboni, Pietro; Chaudhary, Sanjay K.; Chen, Zhe

    2016-01-01

    functions are formulated on the basis of the integral of an error. This difference makes them suitable for the cases where the entire step-response data series are unavailable. The performances of differently tuned regulators are compared considering a test system including a 100 kW Diesel Generator Set......Effects of low reactance to resistance ratio in distribution networks are widely studied but little work dealing with the tuning of voltage and reactive power regulators of small synchronous generators has been reported. This study endeavours the design of a proportional integral controller...

  10. Financial assistance for investments in wind power in Germany. Business incentives provided by the Deutsche Ausgleichsbank

    Energy Technology Data Exchange (ETDEWEB)

    Koch, M [Deutsche Ausgleichsbank, Bonn (Germany)

    1996-12-31

    Within a generous financial framework investments in wind energy power have rapidly increased in Germany since the late 1980`s. In addition to direct subsidies or incentive stipulated by statutory provisions the DtA has encouraged investments in wind energy projects by loans at preferential interest rates with tremendous success and it will continue to do so. At present especially new ways of supporting environmental investments are being seek which have a cross-border environmental impact. The goal is to provide financial assistance both to domestic and foreign companies willing to invest in transboundary projects which may be located in East European Countries

  11. Providing many results of evacuation simulation around a nuclear power plant and its speedy use

    International Nuclear Information System (INIS)

    Ishida, Shoji; Nagase, Shinichiro; Ino, Masanori

    1990-01-01

    According to the peculiar situation around nuclear power plant in Japan, many results of evacuation simulation in that the public buses and family cars were used together have being obtained by a super computer. These were comprised of the time dependence of the number of residents and vehicles at the exit and starting points, and traffic jam datas at each intersection on the evacuation roads. Also, exposed dose for each group of the residents were calculated in case of Xe and I-131 release. The retrieval system was applied for selecting the indispensable data from many results, and in order to see data on the display screen, the graphic system was provided. (author)

  12. Financial assistance for investments in wind power in Germany. Business incentives provided by the Deutsche Ausgleichsbank

    Energy Technology Data Exchange (ETDEWEB)

    Koch, M. [Deutsche Ausgleichsbank, Bonn (Germany)

    1995-12-31

    Within a generous financial framework investments in wind energy power have rapidly increased in Germany since the late 1980`s. In addition to direct subsidies or incentive stipulated by statutory provisions the DtA has encouraged investments in wind energy projects by loans at preferential interest rates with tremendous success and it will continue to do so. At present especially new ways of supporting environmental investments are being seek which have a cross-border environmental impact. The goal is to provide financial assistance both to domestic and foreign companies willing to invest in transboundary projects which may be located in East European Countries

  13. Financial assistance for investments in wind power in Germany. Business incentives provided by the Deutsche Ausgleichsbank

    International Nuclear Information System (INIS)

    Koch, M.

    1995-01-01

    Within a generous financial framework investments in wind energy power have rapidly increased in Germany since the late 1980's. In addition to direct subsidies or incentive stipulated by statutory provisions the DtA has encouraged investments in wind energy projects by loans at preferential interest rates with tremendous success and it will continue to do so. At present especially new ways of supporting environmental investments are being seek which have a cross-border environmental impact. The goal is to provide financial assistance both to domestic and foreign companies willing to invest in transboundary projects which may be located in East European Countries

  14. Measurement of reactivity temperature coefficient by noise method in a power reactor

    International Nuclear Information System (INIS)

    Aguilar, O.

    1986-07-01

    The temperature reactivity coefficient was estimated on the basis of noise measurements performed in a PWR. The magnitude of the coefficient was evaluated by relating the values of the APSD and CPSD between ex-core neutron detector signals and fuel assembly outlet thermocouple in the low frequency range. Comparison with δρ/δT measurements performed in PWR by standard methods supports the validity of the results. (author)

  15. Investigation of Reactive Power Control Effects on Flicker and Harmonics Emission of a DFIG Wind Turbine

    OpenAIRE

    Amir Nagizadeh Ghoogdareh; Aref Doroudi; Mohammad Poormonfared Azimi

    2013-01-01

    One of the most important power quality aspects in wind farms is voltage fluctuation or flicker which should be investigated due to the nature of wind speed variations. These variations result in power and voltage fluctuations at the load bus. Moreover, the wind generation systems may be assumed as a harmonics source because of their power electronic converters. There are numerous factors that affect flicker and harmonic emission of grid-connected wind turbines during continuous operation, su...

  16. MVA power flow and loss analysis for electricity market

    International Nuclear Information System (INIS)

    Wu, Z.Q.; Chen, G.Z.

    2001-01-01

    MVA power-flow and loss analysis is the basis for allocating the fixed costs and power losses under electricity-market deregulation. It is pointed out that the decomposition allocation of active and reactive power losses is not reasonable. The theory of active and reactive loss allocation and branch-power-flow decomposition has been proposed. Various contributory factors have been deduced. These contributory factors include the contribution factors of the active and reactive generation power, load-power-to-branch flows, the contribution factors of active and reactive generation power to active and reactive load power, the contribution factors of active and reactive load power to generation power, and the contribution factors of active and reactive load power and active and reactive generation power to line power losses. The detailed calculation results are presented and analysed, demonstrating that the theory presented provides a good charging algorithm for all the market participants. (Author)

  17. Optimal reactive power and voltage control in distribution networks with distributed generators by fuzzy adaptive hybrid particle swarm optimisation method

    DEFF Research Database (Denmark)

    Chen, Shuheng; Hu, Weihao; Su, Chi

    2015-01-01

    A new and efficient methodology for optimal reactive power and voltage control of distribution networks with distributed generators based on fuzzy adaptive hybrid PSO (FAHPSO) is proposed. The objective is to minimize comprehensive cost, consisting of power loss and operation cost of transformers...... that the proposed method can search a more promising control schedule of all transformers, all capacitors and all distributed generators with less time consumption, compared with other listed artificial intelligent methods....... algorithm is implemented in VC++ 6.0 program language and the corresponding numerical experiments are finished on the modified version of the IEEE 33-node distribution system with two newly installed distributed generators and eight newly installed capacitors banks. The numerical results prove...

  18. Silicon oxynitride films deposited by reactive high power impulse magnetron sputtering using nitrous oxide as a single-source precursor

    Energy Technology Data Exchange (ETDEWEB)

    Hänninen, Tuomas, E-mail: tuoha@ifm.liu.se; Schmidt, Susann; Jensen, Jens; Hultman, Lars; Högberg, Hans [Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping SE-581 83 (Sweden)

    2015-09-15

    Silicon oxynitride thin films were synthesized by reactive high power impulse magnetron sputtering of silicon in argon/nitrous oxide plasmas. Nitrous oxide was employed as a single-source precursor supplying oxygen and nitrogen for the film growth. The films were characterized by elastic recoil detection analysis, x-ray photoelectron spectroscopy, x-ray diffraction, x-ray reflectivity, scanning electron microscopy, and spectroscopic ellipsometry. Results show that the films are silicon rich, amorphous, and exhibit a random chemical bonding structure. The optical properties with the refractive index and the extinction coefficient correlate with the film elemental composition, showing decreasing values with increasing film oxygen and nitrogen content. The total percentage of oxygen and nitrogen in the films is controlled by adjusting the gas flow ratio in the deposition processes. Furthermore, it is shown that the film oxygen-to-nitrogen ratio can be tailored by the high power impulse magnetron sputtering-specific parameters pulse frequency and energy per pulse.

  19. A global plasma model for reactive deposition of compound films by modulated pulsed power magnetron sputtering discharges

    Science.gov (United States)

    Zheng, B. C.; Wu, Z. L.; Wu, B.; Li, Y. G.; Lei, M. K.

    2017-05-01

    A spatially averaged, time-dependent global plasma model has been developed to describe the reactive deposition of a TiAlSiN thin film by modulated pulsed power magnetron sputtering (MPPMS) discharges in Ar/N2 mixture gas, based on the particle balance and the energy balance in the ionization region, and considering the formation and erosion of the compound at the target surface. The modeling results show that, with increasing the N2 partial pressure from 0% to 40% at a constant working pressure of 0.3 Pa, the electron temperature during the strongly ionized period increases from 4 to 7 eV and the effective power transfer coefficient, which represents the power fraction that effectively heats the electrons and maintains the discharge, increases from about 4% to 7%; with increasing the working pressure from 0.1 to 0.7 Pa at a constant N2 partial pressure of 25%, the electron temperature decreases from 10 to 4 eV and the effective power transfer coefficient decreases from 8% to 5%. Using the modeled plasma parameters to evaluate the kinetic energy of arriving ions, the ion-to-neutral flux ratio of deposited species, and the substrate heating, the variations of process parameters that increase these values lead to an enhanced adatom mobility at the target surface and an increased input energy to the substrate, corresponding to the experimental observation of surface roughness reduction, the microstructure transition from the columnar structure to the dense featureless structure, and the enhancement of phase separation. At higher N2 partial pressure or lower working pressure, the modeling results demonstrate an increase in electron temperature, which shifts the discharge balance of Ti species from Ti+ to Ti2+ and results in a higher return fraction of Ti species, corresponding to the higher Al/Ti ratio of deposited films at these conditions. The modeling results are well correlated with the experimental observation of the composition variation and the microstructure

  20. Active and reactive power control schemes for distributed generation systems under voltage dips

    NARCIS (Netherlands)

    Wang, F.; Duarte, J.L.; Hendrix, M.A.M.

    2009-01-01

    During voltage dips continuous power delivery from distributed generation systems to the grid is desirable for the purpose of grid support. In order to facilitate the control of distributed generation systems adapted to the expected change of grid requirements, generalized power control schemes

  1. Operation and Management of Thermostatically Controlled Loads for Providing Regulation Services to Power Grids

    Science.gov (United States)

    Vanouni, Maziar

    The notion of demand-side participation in power systems operation and control is on the verge of realization because of the advancement in the required technologies an tools like communications, smart meters, sensor networks, large data management techniques, large scale optimization method, etc. Therefore, demand-response (DR) programs can be one of the prosperous solutions to accommodate part of the increasing demand for load balancing services which is brought about by the high penetration of intermittent renewable energies in power systems. This dissertation studies different aspects of the DR programs that utilized the thermostatically controlled loads (TCLs) to provide load balancing services. The importance of TCLs among the other loads lie on their flexibility in power consumption pattern while the customer/end-user comfort is not (or minimally) impacted. Chapter 2 discussed a previously presented direct load control (DLC) to control the power consumption of aggregated TCLs. The DLC method performs a power tracking control and based on central approach where a central controller broadcasts the control command to the dispersed TCLs to toggle them on/off. The central controller receives measurement feedback from the TCLs once per couple of minutes to run a successful forecast process. The performance evaluation criteria to evaluate the load balancing service provided by the TCLs are presented. The results are discussed under different scenarios and situation. The numerical results show the proper performance of the DLC method. This DLC method is used as the control method in all the studies in this dissertation. Chapter 3 presents performance improvements for the original method in Chapter 2 by communicating two more pieces of information called forecast parameters (FPs). Communicating improves the forecast process in the DLC and hence, both performance accuracy and the amount of tear-and-wear imposed on the TCLs. Chapter 4 formulates a stochastic

  2. Effects of anodic potential and chloride ion on overall reactivity in electrochemical reactors designed for solar-powered wastewater treatment.

    Science.gov (United States)

    Cho, Kangwoo; Qu, Yan; Kwon, Daejung; Zhang, Hao; Cid, Clément A; Aryanfar, Asghar; Hoffmann, Michael R

    2014-02-18

    We have investigated electrochemical treatment of real domestic wastewater coupled with simultaneous production of molecular H2 as useful byproduct. The electrolysis cells employ multilayer semiconductor anodes with electroactive bismuth-doped TiO2 functionalities and stainless steel cathodes. DC-powered laboratory-scale electrolysis experiments were performed under static anodic potentials (+2.2 or +3.0 V NHE) using domestic wastewater samples, with added chloride ion in variable concentrations. Greater than 95% reductions in chemical oxygen demand (COD) and ammonium ion were achieved within 6 h. In addition, we experimentally determined a decreasing overall reactivity of reactive chlorine species toward COD with an increasing chloride ion concentration under chlorine radicals (Cl·, Cl2(-)·) generation at +3.0 V NHE. The current efficiency for COD removal was 12% with the lowest specific energy consumption of 96 kWh kgCOD(-1) at the cell voltage of near 4 V in 50 mM chloride. The current efficiency and energy efficiency for H2 generation were calculated to range from 34 to 84% and 14 to 26%, respectively. The hydrogen comprised 35 to 60% by volume of evolved gases. The efficacy of our electrolysis cell was further demonstrated by a 20 L prototype reactor totally powered by a photovoltaic (PV) panel, which was shown to eliminate COD and total coliform bacteria in less than 4 h of treatment.

  3. THE EVALUATION OF THE EFFECT OF REACTIVE POWER COMPENSATION IN ELECTRIC POWER LOSSES IN ELECTRIC NETWORK OF RAILWAY JUNCTION

    OpenAIRE

    O. I. Bondar; I. L. Bondar

    2009-01-01

    In this work the generalized mathematical model of an electrical network of the electrified railway junction is proposed. An estimation of influence of static var compensators installation on electric power losses in a network is executed on the basis of given model.

  4. 18 CFR 284.505 - Market-based rates for storage providers without a market-power determination.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Market-based rates for storage providers without a market-power determination. 284.505 Section 284.505 Conservation of Power and... UNDER THE NATURAL GAS POLICY ACT OF 1978 AND RELATED AUTHORITIES Applications for Market-Based Rates for...

  5. Power reactor services provided by the Penn State Radiation Science and Engineering Center

    International Nuclear Information System (INIS)

    Voth, M.H.; Jester, W.A.

    1993-01-01

    The power reactor industry emerged from extensive research and development performed at nonpower reactors (NPRs). As the industry matures, NPRs continue to support and enhance power reactor technology. With the closure of many government and private industry NPRS, there is an increasing call for the 33 universities with operating research reactors to provide the needed services. The Penn State Radiation Science and Engineering Center (RSEC) includes a 1-MW pool-type pulsing TRIGA reactor, a neutron beam laboratory with real-time neutron radiography equipment, hot cells with master-slave manipulators for remote handling of radioactive materials, a gamma-ray irradiation pool, a low-level radiation monitoring laboratory, and extensive equipment for radiation monitoring, dosimetry, and material properties determination. While equipment is heavily utilized in the instructional and academic research programs, significant time remains available for service work. Cost recovery for service work generates income for personnel, equipment maintenance, and facility improvements. With decreasing federal and state funding for educational programs, it is increasingly important that facilities be fully utilized to generate supplementary revenue. The following are examples of such work performed at the RSEC

  6. Quantifying the value that wind power provides as a hedge against volatile natural gas prices

    Energy Technology Data Exchange (ETDEWEB)

    Bolinger, Mark; Wiser, Ryan; Golove, William

    2002-05-31

    Advocates of renewable energy have long argued that wind power and other renewable technologies can mitigate fuel price risk within a resource portfolio. Such arguments--made with renewed vigor in the wake of unprecedented natural gas price volatility during the winter of 2000/2001--have mostly been qualitative in nature, however, with few attempts to actually quantify the price stability benefit that wind and other renewables provide. This paper attempts to quantify this benefit by equating it with the cost of achieving price stability through other means, particularly gas-based financial derivatives (futures and swaps). We find that over the past two years, natural gas consumers have had to pay a premium of roughly 0.50 cents/kWh over expected spot prices to lock in natural gas prices for the next 10 years. This incremental cost is potentially large enough to tip the scales away from new investments in natural gasfired generation and in favor of investments in wind power and other renewable technologies.

  7. A new islanding detection technique for multiple mini hydro based on rate of change of reactive power and load connecting strategy

    International Nuclear Information System (INIS)

    Laghari, J.A.; Mokhlis, H.; Bakar, A.H.A.; Karimi, M.

    2013-01-01

    Highlights: • The requirement of DG interconnection with existing power system is discussed. • Various islanding detection techniques are discussed with their merits and demerits. • New islanding detection strategy is proposed for multiple mini hydro type DGs. • The proposed strategy is based on dq/dt and load connecting strategy. • The effectiveness of strategy is verified on various other cases. - Abstract: The interconnection of distributed generation (DG) into distribution networks is undergoing a rapid global expansion. It enhances the system’s reliability, while simultaneously reduces pollution problems related to the generation of electrical power. To fully utilize the benefits of DGs, certain technical issues need to be addressed. One of the most important issues in this context is islanding detection. This paper presents a new islanding detection technique that is suitable for multiple mini-hydro type DG units. The proposed strategy is based on the rate of change of reactive power and load connecting strategy to detect islanding within the system. For a large power mismatch, islanding is detected by rate of change of reactive power only. However, for a close power mismatch, the rate of change of reactive power initiates a load connecting strategy, which in turn alters the load on the distribution network. This load variation in the distribution network causes a variation in the rate of change of reactive power, which is utilized to distinguish islanding and other events. The simulation results show that the proposed strategy is effective in detecting islanding occurrence in a distribution network

  8. Measurement of the CNA I's (Atucha I nuclear power plant) control rods reactivity during its commissioning on January 8th, 1990

    International Nuclear Information System (INIS)

    Waldman, R.M.; Gomez, A.

    1990-01-01

    Measurements were made on integral and differential calibration of rod 16, fuel racks RG and R3 and extinction reactivity during Atucha I nuclear power plant's commissioning on January 8th., 1990. These were the first physical measurements performed after the first critical nuclear power plant's commissioning. (Author) [es

  9. Wide variation in hospital and physician payment rates evidence of provider market power.

    Science.gov (United States)

    Ginsburg, Paul B

    2010-11-01

    Wide variation in private insurer payment rates to hospitals and physicians across and within local markets suggests that some providers, particularly hospitals, have significant market power to negotiate higher-than-competitive prices, according to a new study by the Center for Studying Health System Change (HSC). Looking across eight health care markets--Cleveland; Indianapolis; Los Angeles; Miami; Milwaukee; Richmond, Va.; San Francisco; and rural Wisconsin--average inpatient hospital payment rates of four large national insurers ranged from 147 percent of Medicare in Miami to 210 percent in San Francisco. In extreme cases, some hospitals command almost five times what Medicare pays for inpatient services and more than seven times what Medicare pays for outpatient care. Variation within markets was just as dramatic. For example, the hospital with prices at the 25th percentile of Los Angeles hospitals received 84 percent of Medicare rates for inpatient care, while the hospital with prices at the 75th percentile received 184 percent of Medicare rates. The highest-priced Los Angeles hospital with substantial inpatient claims volume received 418 percent of Medicare. While not as pronounced, significant variation in physician payment rates also exists across and within markets and by specialty. Few would characterize the variation in hospital and physician payment rates found in this study to be consistent with a highly competitive market. Purchasers and public policy makers can address provider market power, or the ability to negotiate higher-than-competitive prices, through two distinct approaches. One is to pursue market approaches to strengthen competitive forces, while the other is to constrain payment rates through regulation.

  10. A novel islanding detection scheme for synchronous distributed generation using rate of change of exciter voltage over reactive power at DG-Side

    DEFF Research Database (Denmark)

    Rostami, Ali; Bagheri, Marzieh; Naderi, Seyed Behzad

    2017-01-01

    , the reactive power at DG-side and exciter voltage parameters are selected. The performance of the proposed method is investigated in MATLAB/Simulink software on a sample network in the presence of synchronous diesel-generator. The simulation results indicate that the proposed method is capable to detect all......Penetration of distributed generation (DG) in distribution networks is rapidly increasing. DGs' application enhances system's reliability and power quality. However, along their benefits, there are some issues. One of the most important issues of DGs' application is the islanding. This paper...... of the synchronous generator. Therefore, due to lack of inertia, response of these parameters to small changes is faster than the other passive parameters such as frequency. However, the sensitivity of reactive power at the DG-side and the exciter voltage is much more than reactive power and voltage of the load. So...

  11. Calculation methods of reactivity using derivatives of nuclear power and Filter fir; Metodos para o calculo da reatividade usando derivadas da potencia nuclear e o filtro FIR

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, Daniel Suescun

    2007-07-01

    This work presents two new methods for the solution of the inverse point kinetics equation. The first method is based on the integration by parts of the integral of the inverse point kinetics equation, which results in a power series in terms of the nuclear power in time dependence. Applying some conditions to the nuclear power, the reactivity is represented as first and second derivatives of this nuclear power. This new calculation method for reactivity has special characteristics, amongst which the possibility of using different sampling periods, and the possibility of restarting the calculation, after its interruption associated it with a possible equipment malfunction, allowing the calculation of reactivity in a non-continuous way. Apart from this reactivity can be obtained with or without dependency on the nuclear power memory. The second method is based on the Laplace transform of the point kinetics equations, resulting in an expression equivalent to the inverse kinetics equation as a function of the power history. The reactivity can be written in terms of the summation of convolution with response to impulse, characteristic of a linear system. For its digital form the Z-transform is used, which is the discrete version of the Laplace transform. In this method it can be pointed out that the linear part is equivalent to a filter named Finite Impulse Response (Fir). The Fir filter will always be, stable and non-varying in time, and, apart from this, it can be implemented in the non-recursive way. This type of implementation does not require feedback, allowing the calculation of reactivity in a continuous way. The proposed methods were validated using signals with random noise and showing the relationship between the reactivity difference and the degree of the random noise. (author)

  12. Power Relations and Health Care Communication in Older Adulthood: Educating Recipients and Providers.

    Science.gov (United States)

    Eliassen, A Henry

    2016-12-01

    Unequal power relations lie just below the surface in much of today's discourse on health care communication with older adults. Focusing on pathologies or deficits tends to reinforce stereotypes of frailty and dependency, thus framing elders as a vulnerable group requiring special assistance. Implicit stereotyping frequently colors interactions of health care personnel with older clients and their families-interactions likely to affect elders' perceptions and health outcomes. Health care providers need to be attuned to the vast and growing diversity in today's older population, wherein many older adults are exemplars of what it takes to marshal resources and cope with multifaceted challenges. Thus, elders have the potential to teach medical personnel through narratives of resilience as well as tribulation. This potential can be fully realized, however, only in contexts where communication patterns characterized by paternalism, consumerism, and collaboration are mutually recognized and selectively challenged or implemented. Promising interventions to facilitate health care communication in older adulthood might well be directed toward (a) educating both recipients and providers to become more mindful of cues that evoke stereotypical thinking, (b) promoting an institutional culture that normalizes situationally appropriate assertive responses to stereotyping, and (c) formally ratifying older adults' life experience in the training of health care personnel. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Reactive Power Compensation of a 24 MW Wind Farm using a 12-Pulse Voltage Source Converter

    DEFF Research Database (Denmark)

    Pedersen, Knud Ole Helgesen; Pedersen, Jørgen Kaas

    1998-01-01

    Integration of large wind farms in distribution and transmission systems may have severe influence on the power quality at the connection point and may also influence the voltage controlling capability of the electrical system. The purpose of the described project has been to develop and investig......Integration of large wind farms in distribution and transmission systems may have severe influence on the power quality at the connection point and may also influence the voltage controlling capability of the electrical system. The purpose of the described project has been to develop...... and investigate the use of a STATCOM by modelling and field testing an 8 MVar unit in a 24 MW wind farm....

  14. Reactive power and voltage control based on general quantum genetic algorithms

    DEFF Research Database (Denmark)

    Vlachogiannis, Ioannis (John); Østergaard, Jacob

    2009-01-01

    This paper presents an improved evolutionary algorithm based on quantum computing for optima l steady-state performance of power systems. However, the proposed general quantum genetic algorithm (GQ-GA) can be applied in various combinatorial optimization problems. In this study the GQ-GA determines...... techniques such as enhanced GA, multi-objective evolutionary algorithm and particle swarm optimization algorithms, as well as the classical primal-dual interior-point optimal power flow algorithm. The comparison demonstrates the ability of the GQ-GA in reaching more optimal solutions....

  15. Raman spectroscopy provides a powerful diagnostic tool for accurate determination of albumin glycation.

    Science.gov (United States)

    Dingari, Narahara Chari; Horowitz, Gary L; Kang, Jeon Woong; Dasari, Ramachandra R; Barman, Ishan

    2012-01-01

    We present the first demonstration of glycated albumin detection and quantification using Raman spectroscopy without the addition of reagents. Glycated albumin is an important marker for monitoring the long-term glycemic history of diabetics, especially as its concentrations, in contrast to glycated hemoglobin levels, are unaffected by changes in erythrocyte life times. Clinically, glycated albumin concentrations show a strong correlation with the development of serious diabetes complications including nephropathy and retinopathy. In this article, we propose and evaluate the efficacy of Raman spectroscopy for determination of this important analyte. By utilizing the pre-concentration obtained through drop-coating deposition, we show that glycation of albumin leads to subtle, but consistent, changes in vibrational features, which with the help of multivariate classification techniques can be used to discriminate glycated albumin from the unglycated variant with 100% accuracy. Moreover, we demonstrate that the calibration model developed on the glycated albumin spectral dataset shows high predictive power, even at substantially lower concentrations than those typically encountered in clinical practice. In fact, the limit of detection for glycated albumin measurements is calculated to be approximately four times lower than its minimum physiological concentration. Importantly, in relation to the existing detection methods for glycated albumin, the proposed method is also completely reagent-free, requires barely any sample preparation and has the potential for simultaneous determination of glycated hemoglobin levels as well. Given these key advantages, we believe that the proposed approach can provide a uniquely powerful tool for quantification of glycation status of proteins in biopharmaceutical development as well as for glycemic marker determination in routine clinical diagnostics in the future.

  16. Raman Spectroscopy Provides a Powerful Diagnostic Tool for Accurate Determination of Albumin Glycation

    Science.gov (United States)

    Dingari, Narahara Chari; Horowitz, Gary L.; Kang, Jeon Woong; Dasari, Ramachandra R.; Barman, Ishan

    2012-01-01

    We present the first demonstration of glycated albumin detection and quantification using Raman spectroscopy without the addition of reagents. Glycated albumin is an important marker for monitoring the long-term glycemic history of diabetics, especially as its concentrations, in contrast to glycated hemoglobin levels, are unaffected by changes in erythrocyte life times. Clinically, glycated albumin concentrations show a strong correlation with the development of serious diabetes complications including nephropathy and retinopathy. In this article, we propose and evaluate the efficacy of Raman spectroscopy for determination of this important analyte. By utilizing the pre-concentration obtained through drop-coating deposition, we show that glycation of albumin leads to subtle, but consistent, changes in vibrational features, which with the help of multivariate classification techniques can be used to discriminate glycated albumin from the unglycated variant with 100% accuracy. Moreover, we demonstrate that the calibration model developed on the glycated albumin spectral dataset shows high predictive power, even at substantially lower concentrations than those typically encountered in clinical practice. In fact, the limit of detection for glycated albumin measurements is calculated to be approximately four times lower than its minimum physiological concentration. Importantly, in relation to the existing detection methods for glycated albumin, the proposed method is also completely reagent-free, requires barely any sample preparation and has the potential for simultaneous determination of glycated hemoglobin levels as well. Given these key advantages, we believe that the proposed approach can provide a uniquely powerful tool for quantification of glycation status of proteins in biopharmaceutical development as well as for glycemic marker determination in routine clinical diagnostics in the future. PMID:22393405

  17. Theoretical and experimental study of a reactive steam jet in molten sodium. Application to the wastage of steam generators of FBR power plants

    International Nuclear Information System (INIS)

    Lestrat, Patrice.

    1982-11-01

    This study aims to analyze and explain the structure of a reactive jet of water steam in liquid sodium, as from a ligh pressure tank and an orifice of very small section. The prior understanding of this reactive jet makes it possible to explain certain results of erosion-corrosion (Wastage) that can occur in the steam generators of breader reactor power stations. This study gave rise to an experimental simulation (plane jet of water steam on a bed of sodium), as well as to suggesting a reactive jet model according to the principle of an ''immersed Na-H 2 O diffusion flame'' [fr

  18. An Enhanced Instantaneous Circulating Current Control for Reactive power and Harmonic Load Sharing in Islanded Microgrids

    DEFF Research Database (Denmark)

    Lorzadeh, Iman; Askarian Abyaneh, Hossein; Savaghebi, Mehdi

    2017-01-01

    To address inaccurate load demand sharing problems among parallel inverter-interfaced voltage-controlled distributed generation (DG) units in islanded microgrids with different DG power ratings and mismatched feeder impedances, an enhanced voltage control scheme based on actively compensation of ...

  19. Reactive Power Compensation of a 24 MW Wind Farm using a 12-Pulse Voltage Source Converter

    DEFF Research Database (Denmark)

    Søbrink, K.H.; Pedersen, Jørgen Kaas; Pedersen, Knud Ole Helgesen

    1998-01-01

    Integration of large wind farms in distribution and transmission systems may have severe influence on the power quality at the connection point and may also influence the voltage controlling capability of the electrical system. The purpose of the described project has been to develop and investig...

  20. Reactive Power Control in Eight Bus System Using FC-TCR

    Directory of Open Access Journals (Sweden)

    Thangavelu Vijayakumar

    2010-02-01

    Full Text Available This paper deals with the simulation of eight bus system having fixed capacitor and thyristor controlled reactor. The system is modeled and simulated using MATLAB.The simulation results are presented. The power and control circuits are simulated. The current drawn by the TCR varies with the variation in the firing angle. The simulation results are compared with the theoretical results.

  1. Development of a standard for calculation and measurement of the moderator temperature coefficient of reactivity in water-moderated power reactors

    International Nuclear Information System (INIS)

    Mosteller, R.D.; Hall, R.A.; Lancaster, D.B.; Young, E.H.; Gavin, P.H.; Robertson, S.T.

    1998-01-01

    The contents of ANS 19.11, the standard for ''Calculation and Measurement of the Moderator Temperature Coefficient of Reactivity in Water-Moderated Power Reactors,'' are described. The standard addresses the calculation of the moderator temperature coefficient (MTC) both at standby conditions and at power. In addition, it describes several methods for the measurement of the at-power MTC and assesses their relative advantages and disadvantages. Finally, it specifies a minimum set of documentation requirements for compliance with the standard

  2. Measuring modules for the research of compensators of reactive power with voltage stabilization in MATLAB

    Science.gov (United States)

    Vlasayevsky, Stanislav; Klimash, Stepan; Klimash, Vladimir

    2017-10-01

    A set of mathematical modules was developed for evaluation the energy performance in the research of electrical systems and complexes in the MatLab. In the electrotechnical library SimPowerSystems of the MatLab software, there are no measuring modules of energy coefficients characterizing the quality of electricity and the energy efficiency of electrical apparatus. Modules are designed to calculate energy coefficients characterizing the quality of electricity (current distortion and voltage distortion) and energy efficiency indicators (power factor and efficiency) are presented. There are described the methods and principles of building the modules. The detailed schemes of modules built on the elements of the Simulink Library are presented, in this connection, these modules are compatible with mathematical models of electrical systems and complexes in the MatLab. Also there are presented the results of the testing of the developed modules and the results of their verification on the schemes that have analytical expressions of energy indicators.

  3. Automatic determination of pressurized water reactor core loading patterns that maximize beginning-of-cycle reactivity within power-peaking and burnup constraints

    International Nuclear Information System (INIS)

    Hobson, G.H.; Turinsky, P.J.

    1986-01-01

    Computational capability has been developed to automatically determine a good estimate of the core loading pattern, which minimizes fuel cycle costs for a pressurized water reactor (PWR). Equating fuel cycle cost minimization with core reactivity maximization, the objective is to determine the loading pattern that maximizes core reactivity while satisfying power peaking, discharge burnup, and other constraints. The method utilizes a two-dimensional, coarse-mesh, finite difference scheme to evaluate core reactivity and fluxes for an initial reference loading pattern. First-order perturbation theory is applied to determine the effects of assembly shuffling on reactivity, power distribution, end-of-cycle burnup. Monte Carlo integer programming is then used to determine a near-optimal loading pattern within a range of loading patterns near the reference pattern. The process then repeats with the new loading pattern as the reference loading pattern and terminates when no better loading pattern can be determined. The process was applied with both reactivity maximization and radial power-peaking minimization as objectives. Results on a typical large PWR indicate that the cost of obtaining an 8% improvement in radial power-peaking margin is ≅2% in fuel cycle costs, for the reload core loaded without burnable poisons that was studied

  4. Integration of heterogeneous industrial consumers to provide regulating power to the smart grid

    DEFF Research Database (Denmark)

    Rahnama, Samira; Stoustrup, Jakob; Rasmussen, Henrik

    2013-01-01

    In this paper, we propose a framework to utilize the flexibility of consumers in the future smart grid with a high share of fluctuating power. Focus is on industrial cases, where a total power consumption of a few number of consumers are large enough in order to bid in the market. Heterogeneous...

  5. Assessment of transient stability of cable based transmission grids with reactive power compensation

    DEFF Research Database (Denmark)

    Foo, Yii; Dall, Laurids; Silva, Filipe Miguel Faria da

    2017-01-01

    Underground transmission cables are gaining popularity due to its applications near cities and aesthetic purpose. For example in Denmark, the transmission power grid is changing significantly as many conventional overhead lines (OHL) are replaced by cables and more is expected over the coming years...... through a series of sensitivity analysis with respect to the cables compensation degree. A separate case of disconnecting the SRs of the faulted line is also carried out. The tendencies are initially observed and explained for smaller systems, Single-Machine Infinite Bus (SMIB) and 9-bus system...

  6. Reactive Inkjet Printing of Biocompatible Enzyme Powered Silk Micro-Rockets.

    Science.gov (United States)

    Gregory, David A; Zhang, Yu; Smith, Patrick J; Zhao, Xiubo; Ebbens, Stephen J

    2016-08-01

    Inkjet-printed enzyme-powered silk-based micro-rockets are able to undergo autonomous motion in a vast variety of fluidic environments including complex media such as human serum. By means of digital inkjet printing it is possible to alter the catalyst distribution simply and generate varying trajectory behavior of these micro-rockets. Made of silk scaffolds containing enzymes these micro-rockets are highly biocompatible and non-biofouling. © 2016 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. 76 FR 39870 - PJM Interconnection, LLC; PJM Power Providers Group v. PJM Interconnection, LLC; Notice of Date...

    Science.gov (United States)

    2011-07-07

    .... EL11-20-001] PJM Interconnection, LLC; PJM Power Providers Group v. PJM Interconnection, LLC; Notice of... Sell Offers for Planned Generation Capacity Resources submitted into PJM's Reliability Pricing Model... presents an opportunity to exercise buyer market power; (2) whether the Fixed Resource Requirement (FRR...

  8. Substantial difference in target surface chemistry between reactive dc and high power impulse magnetron sputtering

    Science.gov (United States)

    Greczynski, G.; Mráz, S.; Schneider, J. M.; Hultman, L.

    2018-02-01

    The nitride layer formed in the target race track during the deposition of stoichiometric TiN thin films is a factor 2.5 thicker for high power impulse magnetron sputtering (HIPIMS), compared to conventional dc processing (DCMS). The phenomenon is explained using x-ray photoelectron spectroscopy analysis of the as-operated Ti target surface chemistry supported by sputter depth profiles, dynamic Monte Carlo simulations employing the TRIDYN code, and plasma chemical investigations by ion mass spectrometry. The target chemistry and the thickness of the nitride layer are found to be determined by the implantation of nitrogen ions, predominantly N+ and N2+ for HIPIMS and DCMS, respectively. Knowledge of this method-inherent difference enables robust processing of high quality functional coatings.

  9. Study on reactor power transient characteristics (reactor training experiments). Control rod reactivity calibration by positive period method and other experiment

    International Nuclear Information System (INIS)

    Ozaki, Yoshihiko; Sunagawa, Takeyoshi

    2014-01-01

    In this paper, it is reported about some experiments that have been carried out in the reactor training that targets sophomore of the department of applied nuclear engineering, FUT. Reactor of Kinki University Atomic Energy Research Institute (UTR-KINKI) was used for reactor training. When each critical state was achieved at different reactor output respectively in reactor operating, it was confirmed that the control rod position at that time does not change. Further, control rod reactivity calibration experiments using positive Period method were carried out for shim safety rod and regulating rod, respectively. The results were obtained as reasonable values in comparison with the nominal value of the UTR-KINKI. The measurement of reactor power change after reactor scram was performed, and the presence of the delayed neutron precursor was confirmed by calculating the half-life. The spatial dose rate measurement experiment of neutrons and γ-rays in the reactor room in a reactor power 1W operating conditions were also performed. (author)

  10. DC microgrids providing frequency regulation in electrical power system - imperfect communication issues

    DEFF Research Database (Denmark)

    Bašić, Hrvoje; Dragicevic, Tomislav; Pandžić, Hrvoje

    2017-01-01

    This paper presents a model of multiple DC microgrids with battery energy storage systems and demand response capability, taking part in primary frequency regulation of electrical power system. Although DC microgrids can contribute to stability and efficiency of frequency regulation, these complex...... systems may cause serious stability issues due to the imperfect communication. This work presents possible scenarios of unstable primary frequency regulation in a simplified model of electrical power system with DC microgrids, which are controlled through communication network....

  11. Voltage sensitivity based reactive power control on VSC-HVDC in a wind farm connected hybrid multi-infeed HVDC system

    DEFF Research Database (Denmark)

    Liu, Yan; Chen, Zhe

    2013-01-01

    With increasing application of both Line Commutated Converter based High Voltage Direct Current (LCC-HVDC) systems and Voltage Source Converter based HVDC (VSC-HVDC) links, a new type of system structure named Hybrid Multi-Infeed HVDC (HMIDC) system is formed in the modern power systems. This paper...... presents the operation and control method of the wind farm connected HMIDC system. The wind power fluctuation takes large influence to the system voltages. In order to reduce the voltage fluctuation of LCC-HVDC infeed bus caused by the wind power variation, a voltage sensitivity-based reactive power...

  12. Evaluation of CANDU6 PCR (power coefficient of reactivity) with a 3-D whole-core Monte Carlo Analysis

    International Nuclear Information System (INIS)

    Motalab, Mohammad Abdul; Kim, Woosong; Kim, Yonghee

    2015-01-01

    Highlights: • The PCR of the CANDU6 reactor is slightly negative at low power, e.g. <80% P. • Doppler broadening of scattering resonances improves noticeably the FTC and make the PCR more negative or less positive in CANDU6. • The elevated inlet coolant condition can worsen significantly the PCR of CANDU6. • Improved design tools are needed for the safety evaluation of CANDU6 reactor. - Abstract: The power coefficient of reactivity (PCR) is a very important parameter for inherent safety and stability of nuclear reactors. The combined effect of a relatively less negative fuel temperature coefficient and a positive coolant temperature coefficient make the CANDU6 (CANada Deuterium Uranium) PCR very close to zero. In the original CANDU6 design, the PCR was calculated to be clearly negative. However, the latest physics design tools predict that the PCR is slightly positive for a wide operational range of reactor power. It is upon this contradictory observation that the CANDU6 PCR is re-evaluated in this work. In our previous study, the CANDU6 PCR was evaluated through a standard lattice analysis at mid-burnup and was found to be negative at low power. In this paper, the study was extended to a detailed 3-D CANDU6 whole-core model using the Monte Carlo code Serpent2. The Doppler broadening rejection correction (DBRC) method was implemented in the Serpent2 code in order to take into account thermal motion of the heavy uranium nucleus in the neutron-U scattering reactions. Time-average equilibrium core was considered for the evaluation of the representative PCR of CANDU6. Two thermal hydraulic models were considered in this work: one at design condition and the other at operating condition. Bundle-wise distributions of the coolant properties are modeled and the bundle-wise fuel temperature is also considered in this study. The evaluated nuclear data library ENDF/B-VII.0 was used throughout this Serpent2 evaluation. In these Monte Carlo calculations, a large number

  13. Star Power: Providing for the Gifted & Talented. Module 1. Characteristics of the Gifted/Talented.

    Science.gov (United States)

    Heinemann, Alison

    The document presents Module 1, characteristics of the gifted/talented student, of the Star Power modules, developed for school personnel who have an interest in or a need to explore the area of gifted and talented education. It is explained in an introductory section that the modules can be used for independent study, for small group interaction,…

  14. Star Power: Providing for the Gifted & Talented. Module 6. Underachievers Among the Gifted/Talented.

    Science.gov (United States)

    Heinemann, Alison

    The document presents Module 6, underachievers among the gifted/talented, of the Star Power modules developed for school personnel who have an interest in or a need to explore the area of gifted and talented education. It is explained in an introductory section that the modules can be used for independent study, for small group interaction, or for…

  15. Star Power: Providing for the Gifted & Talented. Module 9. Programs for the Gifted/Talented.

    Science.gov (United States)

    Mallis, Jackie; Heinemann, Alison

    The document presents Module 9, programs for the gifted/talented, of the Star Power modules developed for school personnel who have an interest in or a need to explore the area of gifted and talented education. It is explained in an introductory section that the modules can be used for independent study, for small group interaction, or for a large…

  16. Modular Biopower System Providing Combined Heat and Power for DoD Installations

    Science.gov (United States)

    2013-12-01

    industry surged with new exploration and tertiary recovery techniques ( fracking and so forth). In the first quarter of 2012, we received permission to...itself on demand, with its hydraulically operated moving floor using system generated power. We required a bit less than two woodchip deliveries per

  17. Providing Contexts for Understanding Musical Narratives of Power in the Classroom: Music, Politics, and Power in Grenada, West Indies

    Science.gov (United States)

    Sirek, Danielle

    2016-01-01

    The role of music in Grenada, West Indies has traditionally been to pass on knowledges, values, and ideals; and to provide a means of connecting to one another through expressing commonality of experience, ancestry, and nationhood. This paper explores how Eric Matthew Gairy, during his era of political leadership in Grenada (1951-1979), exploited…

  18. Influence of reactive oxygen species during deposition of iron oxide films by high power impulse magnetron sputtering

    Science.gov (United States)

    Stranak, V.; Hubicka, Z.; Cada, M.; Bogdanowicz, R.; Wulff, H.; Helm, C. A.; Hippler, R.

    2018-03-01

    Iron oxide films were deposited using high power impulse magnetron sputtering (HiPIMS) of an iron cathode in an argon/oxygen gas mixture at different gas pressures (0.5 Pa, 1.5 Pa, and 5.0 Pa). The HiPIMS system was operated at a repetition frequency f  =  100 Hz with a duty cycle of 1%. A main goal is a comparison of film growth during conventional and electron cyclotron wave resonance-assisted HiPIMS. The deposition plasma was investigated by means of optical emission spectroscopy and energy-resolved mass spectrometry. Active oxygen species were detected and their kinetic energy was found to depend on the gas pressure. Deposited films were characterized by means of spectroscopic ellipsometry and grazing incidence x-ray diffraction. Optical properties and crystallinity of as-deposited films were found to depend on the deposition conditions. Deposition of hematite iron oxide films with the HiPIMS-ECWR discharge is attributed to the enhanced production of reactive oxygen species.

  19. Effects of Void Uncertainties on Pin Power Distributions and the Void Reactivity Coefficient for a 10X10 BWR Assembly

    International Nuclear Information System (INIS)

    Jatuff, F.; Krouthen, J.; Helmersson, S.; Chawla, R.

    2004-01-01

    A significant source of uncertainty in Boiling Water Reactor physics is associated with the precise characterisation of the axially-dependent neutron moderation properties of the coolant inside the fuel assembly channel, and the corresponding effects on reactor physics parameters such as the lattice neutron multiplication, the neutron migration length, and the pin-by-pin power distribution. In this paper, the effects of particularly relevant void fraction uncertainties on reactor physics parameters have been studied for a BWR assembly of type Westinghouse SVEA-96 using the CASMO-4, HELIOS/PRESTO-2 and MCNP4C codes. The SVEA-96 geometry is characterised by the sub-division of the assembly into four different sub-bundles by means of an inner bypass with a cruciform shape. The study has covered the following issues: (a) the effects of different cross-section data libraries on the void coefficient of reactivity, for a wide range of void fractions; (b) the effects due to a heterogeneous vs. homogeneous void distribution inside the sub-bundles; and (c) the consequences of partly inserted absorber blades producing different void fractions in different sub-bundles. (author)

  20. Allocation of reactive power support, active loss balancing and demand interruption ancillary services in MicroGrids

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Mario Helder [Departamento de Engenharia Electrotecnica, Instituto Politecnico de Tomar, Quinta do Contador, Estrada da Serra, 2300 Tomar (Portugal); Saraiva, Joao Tome [INESC Porto and Faculdade de Engenharia da Universidade do Porto, Campus da FEUP, Rua Dr. Roberto Frias, 4200 - 465 Porto (Portugal)

    2010-10-15

    MicroGrids represent a new paradigm for the operation of distribution systems and there are several advantages as well as challenges regarding their development. One of the advantages is related with the participation of MicroGrid agents in electricity markets and in the provision of ancillary services. This paper describes two optimization models to allocate three ancillary services among MicroGrid agents - reactive power/voltage control, active loss balancing and demand interruption. These models assume that MicroGrid agents participate in the day-ahead market sending their bids to the MicroGrid Central Controller, MGCC, that acts as an interface with the Market Operator. Once the Market Operator returns the economic dispatch of the MicroGrid agents, the MGCC checks its technical feasibility (namely voltage magnitude and branch flow limits) and activates an adjustment market to change the initial schedule and to allocate these three ancillary services. One of the models has crisp nature considering that voltage and branch flow limits are rigid while the second one admits that voltage and branch flow limits are modeled in a soft way using Fuzzy Set concepts. Finally, the paper illustrates the application of these models with a Case Study using a 55 node MV/LV network. (author)

  1. Reactive Power Control of Single-Stage Three-Phase Photovoltaic System during Grid Faults Using Recurrent Fuzzy Cerebellar Model Articulation Neural Network

    Directory of Open Access Journals (Sweden)

    Faa-Jeng Lin

    2014-01-01

    Full Text Available This study presents a new active and reactive power control scheme for a single-stage three-phase grid-connected photovoltaic (PV system during grid faults. The presented PV system utilizes a single-stage three-phase current-controlled voltage-source inverter to achieve the maximum power point tracking (MPPT control of the PV panel with the function of low voltage ride through (LVRT. Moreover, a formula based on positive sequence voltage for evaluating the percentage of voltage sag is derived to determine the ratio of the injected reactive current to satisfy the LVRT regulations. To reduce the risk of overcurrent during LVRT operation, a current limit is predefined for the injection of reactive current. Furthermore, the control of active and reactive power is designed using a two-dimensional recurrent fuzzy cerebellar model articulation neural network (2D-RFCMANN. In addition, the online learning laws of 2D-RFCMANN are derived according to gradient descent method with varied learning-rate coefficients for network parameters to assure the convergence of the tracking error. Finally, some experimental tests are realized to validate the effectiveness of the proposed control scheme.

  2. System Statement of Tasks of Calculating and Providing the Reliability of Heating Cogeneration Plants in Power Systems

    Science.gov (United States)

    Biryuk, V. V.; Tsapkova, A. B.; Larin, E. A.; Livshiz, M. Y.; Sheludko, L. P.

    2018-01-01

    A set of mathematical models for calculating the reliability indexes of structurally complex multifunctional combined installations in heat and power supply systems was developed. Reliability of energy supply is considered as required condition for the creation and operation of heat and power supply systems. The optimal value of the power supply system coefficient F is based on an economic assessment of the consumers’ loss caused by the under-supply of electric power and additional system expences for the creation and operation of an emergency capacity reserve. Rationing of RI of the industrial heat supply is based on the use of concept of technological margin of safety of technological processes. The definition of rationed RI values of heat supply of communal consumers is based on the air temperature level iside the heated premises. The complex allows solving a number of practical tasks for providing reliability of heat supply for consumers. A probabilistic model is developed for calculating the reliability indexes of combined multipurpose heat and power plants in heat-and-power supply systems. The complex of models and calculation programs can be used to solve a wide range of specific tasks of optimization of schemes and parameters of combined heat and power plants and systems, as well as determining the efficiency of various redundance methods to ensure specified reliability of power supply.

  3. Experiences in simulating and testing coordinated voltage control provided by multiple wind power plants

    Energy Technology Data Exchange (ETDEWEB)

    Arlaban, T.; Alonso, O.; Ortiz, D. [Acciona Windpower S.A. (Spain); Peiro, J.; Rivas, R. [Red Electrica de Espana SAU (Spain); Quinonez-Varela, G.; Lorenzo, P. [Acciona Energia S.A. (Spain)

    2011-07-01

    This document presents some field tests performed in a transmission system node in order to check the adequacy of voltage control performance by multiple wind power plants, with an overall capacity of 395 MW. It briefly explains the Spanish TSO motivation towards new voltage control requirements and the necessity of performing such tests in order to set the most convenient voltage control parameters and to verify the stable operation. It presents how different the voltage control capability between modern wind turbines (DFIG) and older ones (SCIG) specifically retrofitted for voltage control is. (orig.)

  4. Analysis on void reactivity of DCA lattice

    International Nuclear Information System (INIS)

    Min, B. J.; Noh, K. H.; Choi, H. B.; Yang, M. K.

    2001-01-01

    In case of loss of coolant accident, the void reactivity of CANDU fuel provides the positive reactivity and increases the reactor power rapidly. Therefore, it is required to secure credibility of the void reactivity for the design and analysis of reactor, which motivated a study to assess the measurement data of void reactivity. The assessment of lattice code was performed with the experimental data of void reactivity at 30, 70, 87 and 100% of void fractions. The infinite multiplication factors increased in four types of fuels as the void fractions of them grow. The infinite multiplication factors of uranium fuels are almost within 1%, but those of Pu fuels are over 10% by the results of WIMS-AECL and MCNP-4B codes. Moreover, coolant void reactivity of the core loaded with plutonium fuel is more negative compared with that with uranium fuel because of spectrum hardening resulting from large void fraction

  5. Active and reactive power for seconds stand-by reserve. Efficiency and profitability of different measures in power plants and networks. Wirkleistung- und Blindleistung-Sekundenreserve. Wirksamkeit und Wirtschaftlichkeit verschiedener Massnahmen in Kraftwerken und Netzen

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    The various methods used for releasing active and reactive power reserves in the seconds range have different static and dynamics effects and involve different investment and operation cost. This two-day conference concerns different methods available to power plants and network for seconds stand-by reserve based on network requirements. Measurements and simulation studies are compared to assess the efficiency of individual methods. The profitability of individual methods is assessed in a comparative study.

  6. Hydrodeoxygenation by deuterium gas--a powerful way to provide insight into the reaction mechanisms.

    Science.gov (United States)

    Ben, Haoxi; Ferguson, Glen A; Mu, Wei; Pu, Yunqiao; Huang, Fang; Jarvis, Mark; Biddy, Mary; Deng, Yulin; Ragauskas, Arthur J

    2013-11-28

    This study demonstrates the use of isotopic labelling and NMR to study the HDO process. As far as we know, this is the first reported effort to trace the incorporation of hydrogen in the HDO process of lignin pyrolysis oil thereby providing key fundamental insight into its reaction mechanism.

  7. Nuclear power plant providing a function of suppressing the deposition of radioactive substance

    International Nuclear Information System (INIS)

    Honda, T.; Kawakami, T.; Izumiya, M.; Minato, A.; Ohsumi, K.

    1988-01-01

    In a nuclear power plant having a cooling system and radioactive coolant in the cooling system, the cooling system is described including ferrous structural material in contact with the radioactive coolant, wherein the ferrous structural material has a preliminary oxide film formed thereon, by oxidation of the bare surface portion thereof, by contacting bare surfaces of the structural material with flowing water containing an oxidizing agent and no metallic ions. The preliminary oxide film is formed at those portions of the ferrous structural material to be in contact with the radioactive coolant. The preliminary oxide film is formed prior to the structural material contacting the radioactive coolant. The preliminary oxide film consists essentially of Fe/sub 2/O/sub 3/ and having a thickness of at least 300 A, whereby later formation of new oxide film while the structural material is in contact with the radioactive coolant is suppressed to thereby suppress deposition of the radioactive substances on the ferrous structural material

  8. INFORMATIVE ADVERTISING: A MARKET INFORMATION PROVIDER OR A SEED OF MARKET POWER?

    Directory of Open Access Journals (Sweden)

    Anzhelika G. GERASYMENKO

    2012-07-01

    Full Text Available This paper investigates the role of informative advertising in creation and augment of market power as well as the ability of an advertiser to maximize the value of its economic rent. Informative advertising is considered to be a merit good unlike a persuasive one that is mostly associated with a bad. But analysis of the advertisement breakdown in Ukraine shows that the share of price advertisements, which are the most beneficial for the public, is negligible today. Further still those advertisements are mostly situated in the sectors, where price competition is the least strong. Another kind of informative advertising – differentiating advertising – turns from an instrument of informing consumers into the vehicle of manipulation of consumer choice. Using the blind tests the author has compared the quality and the prices of the range of advertised goods and has found out a low level of correlation between the variables. That means that informative advertising serves a function of informing consumers inefficiently. At the same time phantom differentiation and misleading advertising proliferation as well as informative advertising concentration on experience and credible goods instead search ones testify to effective serving a function of maximizing advertiser welfare.

  9. The EZ diffusion model provides a powerful test of simple empirical effects.

    Science.gov (United States)

    van Ravenzwaaij, Don; Donkin, Chris; Vandekerckhove, Joachim

    2017-04-01

    Over the last four decades, sequential accumulation models for choice response times have spread through cognitive psychology like wildfire. The most popular style of accumulator model is the diffusion model (Ratcliff Psychological Review, 85, 59-108, 1978), which has been shown to account for data from a wide range of paradigms, including perceptual discrimination, letter identification, lexical decision, recognition memory, and signal detection. Since its original inception, the model has become increasingly complex in order to account for subtle, but reliable, data patterns. The additional complexity of the diffusion model renders it a tool that is only for experts. In response, Wagenmakers et al. (Psychonomic Bulletin & Review, 14, 3-22, 2007) proposed that researchers could use a more basic version of the diffusion model, the EZ diffusion. Here, we simulate experimental effects on data generated from the full diffusion model and compare the power of the full diffusion model and EZ diffusion to detect those effects. We show that the EZ diffusion model, by virtue of its relative simplicity, will be sometimes better able to detect experimental effects than the data-generating full diffusion model.

  10. Instantaneous active and reactive power theory and applications; Teoria de potencia ativa e reativa instantanea e aplicacoes - filtros ativos e FACTS

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Edson H.; Aredes, Mauricio [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Lab. de Eletronica de Potencia]. E-mail: watanabe@coe.ufrj.br, aredes@cce.ufrj.br

    1998-07-01

    A tutorial about the instantaneous active and reactive power theory, which is valid for balanced and unbalanced three-phase systems, with and without harmonics is presented. Based on this theory the basic concepts involving the operation and design of shunt and series active and passive filters are also discussed. The advantage of the association of active and passive filters are also discussed. The association of shunt and series active filters to form the UPQC (Universal Power Quality Conditions), which guarantees the total compensation of voltage and current harmonics is also presented. As a result of the generalization of the UPFC (Unified Power Flow Controller) associated with the UPQC, the UPLC (Universal Active Power Line Conditioner) is proposed to compensate voltage and current harmonics as well as to control the power flow in a transmission line and regulate the ac bus voltage. (author)

  11. 76 FR 45248 - PJM Interconnection, L.L.C., PJM Power Providers Group v. PJM Interconnection, L.L.C...

    Science.gov (United States)

    2011-07-28

    ...-002; Docket No. EL11-20-001] PJM Interconnection, L.L.C., PJM Power Providers Group v. PJM Interconnection, L.L.C.; Supplemental Notice of Staff Technical Conference On June 13, 2011, the Commission issued... Resources Services, Inc., Maryland Public Service Commission, Monitoring Analytics, L.L.C., National Rural...

  12. The Impact of Providing Web-Based PowerPoint Slides as Study Guides in Undergraduate Business Classes

    Science.gov (United States)

    Frank, Jonathan; Shaw, Lewis; Wilson, Elizabeth

    2009-01-01

    This study examines undergraduate business students' use of PowerPoint slides provided as a supplement to class attendance, textbook reading, and other traditional course resources. We survey students in 4 diverse (accounting, marketing, management, and information systems) lower-level undergraduate courses in which the instructor provided…

  13. Benefits of Demand Side Response in Providing Frequency Response Service in the Future GB Power System

    Directory of Open Access Journals (Sweden)

    Fei eTeng

    2015-08-01

    Full Text Available The demand for ancillary service is expected to increase significantly in the future GB electricity system due to high penetration of wind. In particular, the need for frequency response, required to deal with sudden frequency drops following a loss of generator, will increase because of the limited inertia capability of wind plants. This paper quantifies the requirements for primary frequency response and analyses the benefits of frequency response provision from DSR. The results show dramatic changes in frequency response requirements driven by high penetration of wind. Case studies carried out by using an advanced stochastic generation scheduling model suggest that the provision of frequency response from DSR could greatly reduce the system operation cost, wind curtailment and carbon emissions in the future GB system characterised by high penetration of wind. Furthermore, the results demonstrate that the benefit of DSR shows significant diurnal and seasonal variation, whereas an even more rapid (instant delivery of frequency response from DSR could provide significant additional value. Our studies also indicate that the competing technologies to DSR, namely battery storage and more flexible generation could potentially reduce its value by up to 35%, still leaving significant room to deploy DSR as frequency response provider.

  14. Percutaneous Biopsy and Radiofrequency Ablation of Osteoid Osteoma with Excess Reactive New Bone Formation and Cortical Thickening Using a Battery-Powered Drill for Access: A Technical Note

    Energy Technology Data Exchange (ETDEWEB)

    Filippiadis, D., E-mail: dfilippiadis@yahoo.gr; Gkizas, C., E-mail: chgkizas@gmail.com; Kostantos, C., E-mail: drkarpen@yahoo.gr; Mazioti, A., E-mail: argyromazioti@yahoo.gr; Reppas, L., E-mail: l.reppas@yahoo.com; Brountzos, E., E-mail: ebrountz@med.uoa.gr; Kelekis, N., E-mail: kelnik@med.uoa.gr; Kelekis, A., E-mail: akelekis@med.uoa.gr [University General Hospital “ATTIKON”, 2nd Radiology Department (Greece)

    2016-10-15

    PurposeTo report our experience with the use of a battery-powered drill in biopsy and radiofrequency ablation of osteoid osteoma with excess reactive new bone formation. The battery-powered drill enables obtaining the sample while drilling.Materials and MethodsDuring the last 18 months, 14 patients suffering from painful osteoid osteoma with excess reactive new bone formation underwent CT-guided biopsy and radiofrequency ablation. In order to assess and sample the nidus of the osteoid osteoma, a battery-powered drill was used. Biopsy was performed in all cases. Then, coaxially, a radiofrequency electrode was inserted and ablation was performed with osteoid osteoma protocol. Procedure time (i.e., drilling including local anesthesia), amount of scans, technical and clinical success, and the results of biopsy are reported.ResultsAccess to the nidus through the excess reactive new bone formation was feasible in all cases. Median procedure time was 50.5 min. Histologic verification of osteoid osteoma was performed in all cases. Radiofrequency electrode was coaxially inserted within the nidus and ablation was successfully performed in all lesions. Median amount CT scans, performed to control correct positioning of the drill and precise electrode placement within the nidus was 11. There were no complications or material failure reported in our study.ConclusionsThe use of battery-powered drill facilitates access to the osteoid osteoma nidus in cases where excess reactive new bone formation is present. Biopsy needle can be used for channel creation during the access offering at the same time the possibility to extract bone samples.

  15. Swiss Solutions for Providing Electrical Power in Cases of Long-Term Black-Out of the Grid

    International Nuclear Information System (INIS)

    Altkind, Franz; Schmid, Daniel

    2015-01-01

    A better understanding of nuclear power plant electrical system robustness and defence-in-depth may be derived from comparing design and operating practices in member countries. In pursuing this goal, the current paper will focus on Switzerland. It will present in general the protective measures implemented in the Swiss nuclear power plants to ensure power supply, which comply with the 'Defence-in-depth' principle by means of several layers of protection. In particular it will present the measures taken in case of a total station blackout. The different layers supplying electricity may be summed up as follows. The first layer consists of the external main grid, which the plant generators feed into. The second layer is the auxiliary power supply when the power plant is in island mode in case of a failure of the main grid. A third layer is provided by the external reserve grid in case of both a failure of the external main grid and of the auxiliary power supply in island mode. As a fourth layer there exists an emergency electrical power supply. This is supplied either from an emergency diesel generator or a direct feed from a hydroelectric power plant. In the fifth layer, the special emergency electrical power supply from bunkered emergency diesel generators power the special emergency safety system and is activated upon the loss of all external feeds. A sixth layer consists of accident management equipment. Since the Fukushima event, the sixth layer has been reinforced and a seventh layer with off-site accident management equipment has been newly added. The Swiss nuclear safety regulator has analysed the accident. It reviewed the Swiss plants' protection against earthquakes as well as flooding and demanded increased precautionary measures from the Swiss operators in the hypothetical case of a total station blackout, when all the first five layers of supply would fail. In the immediate, a centralized storage with severe accident management equipment

  16. Real-Time Control of Active and Reactive Power for Doubly Fed Induction Generator (DFIG-Based Wind Energy Conversion System

    Directory of Open Access Journals (Sweden)

    Aman Abdulla Tanvir

    2015-09-01

    Full Text Available This paper presents the modeling, rapid control prototyping, and hardware-in-the-loop testing for real-time simulation and control of a grid-connected doubly fed induction generator (DFIG in a laboratory-size wind turbine emulator for wind energy conversation systems. The generator is modeled using the direct-quadrature rotating reference frame circuit along with the aligned stator flux, and the field-oriented control approach is applied for independent control of the active and reactive power and the DC-link voltage at the grid side. The control of the active, reactive power and the DC-link voltage are performed using a back-to-back converter at sub- and super-synchronous as well as at variable speeds. The control strategy is experimentally validated on an emulated wind turbine driven by the Opal-RT real-time simulator (OP5600 for simultaneous control of the DC-link voltage, active and reactive power.

  17. Parametric identification of an asynchronous machine by the reactive power method; Identificacao parametrica de uma maquina assincrona pelo metodo da potencia reativa

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Alexandre Alves Sampaio e

    1996-07-01

    The obtention of the electrical and mechanical parameters of a squirrel-cage induction motor is investigated. Two methods of identification are studied: the reactive power method, used to determine the electrical parameters and an acceleration method on a startup test used to to find the mechanical ones. The method of reactive power is developed by analysing the machine steady state operation. In this analysis, a relationship between the electrical parameters and the reactive power is obtained. A minimization algorithm is used to determine the parameters based on this relationship. The acceleration method uses an acquisition of the transient variables, which is used in a recursive least square method furnishing the mechanical parameters. Both of methods are implemented on a special hardware and software system, consisting of sensors and A/D boards that make a digital acquisition of voltage, current and speed values. The validation procedures for the method and parameters are based on comparing between the real and simulated evaluation of the dynamical behavior of the motor in a startup test. The skin-effect influence over some of the motor parameters was also discussed. (author)

  18. Determination of the relative power density distribution in a heterogeneous reactor from the results of measurements of the reactivity effects and the neutron importance function

    International Nuclear Information System (INIS)

    Bobrov, A. A.; Glushkov, E. S.; Zimin, A. A.; Kapitonova, A. V.; Kompaniets, G. V.; Nosov, V. I.; Petrushenko, R. P.; Smirnov, O. N.

    2012-01-01

    A method for experimental determination of the relative power density distribution in a heterogeneous reactor based on measurements of fuel reactivity effects and importance of neutrons from a californium source is proposed. The method was perfected on two critical assembly configurations at the NARCISS facility of the Kurchatov Institute, which simulated a small-size heterogeneous nuclear reactor. The neutron importance measurements were performed on subcritical and critical assemblies. It is shown that, along with traditionally used activation methods, the developed method can be applied to experimental studies of special features of the power density distribution in critical assemblies and reactors.

  19. Voltage and reactive power in the 380/220 kV power network of the new German Laender - state and prospects. Spannung und Blindleistung im 380/220-kV-Verbundnetz der neuen Bundeslaender - Stand und Ausblick

    Energy Technology Data Exchange (ETDEWEB)

    Behnke, M; Luettig, K; Radtke, H [Verbundnetz Elektroenergie AG, Berlin (Germany)

    1991-01-01

    With the preparation for restoring a German power network after nearly 40 years of separate development of the EES of the former DDR, the voltage/reactive power regulation must be examined and evaluated in the conditions of: - parting the connections to the present VES partners Poland and Czechoslovakia with the option of rectification - taking up parallel operation with the adjacent network undertakings of the old West German Laender (Preussen Elektra AG and Bayernwerke AG), ie: combined operation with DVG (superregional network of old West German Laender) and UCPTE (European electrical energy union). The aim is to configure this in the 380/220 kV network of the new German Laender, so that with a regionally compensated reactive power system, the voltage can be kept steady much better at times of heavy and light load, and the network losses can be reduced. (orig./GL).

  20. MODEL REQUEST FOR PROPOSALS TO PROVIDE ENERGY AND OTHER ATTRIBUTES FROM AN OFFSHORE WIND POWER PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Jeremy Firestone; Dawn Kurtz Crompton

    2011-10-22

    This document provides a model RFP for new generation. The 'base' RFP is for a single-source offshore wind RFP. Required modifications are noted should a state or utility seek multi-source bids (e.g., all renewables or all sources). The model is premised on proposals meeting threshold requirements (e.g., a MW range of generating capacity and a range in terms of years), RFP issuer preferences (e.g., likelihood of commercial operation by a date certain, price certainty, and reduction in congestion), and evaluation criteria, along with a series of plans (e.g., site, environmental effects, construction, community outreach, interconnection, etc.). The Model RFP places the most weight on project risk (45%), followed by project economics (35%), and environmental and social considerations (20%). However, if a multi-source RFP is put forward, the sponsor would need to either add per-MWh technology-specific, life-cycle climate (CO2), environmental and health impact costs to bid prices under the 'Project Economics' category or it should increase the weight given to the 'Environmental and Social Considerations' category.

  1. Automated reactivity anomaly surveillance in the Fast Flux Test Facility

    International Nuclear Information System (INIS)

    Knutson, B.J.; Harris, R.A.; Honeyman, D.J.; Shook, A.T.; Krohn, C.N.

    1985-01-01

    The automated technique for monitoring core reactivity during power operation used at the Fast Flux Test Facility (FFTF) is described. This technique relies on comparing predicted to measured rod positions to detect any anomalous (or unpredicted) core reactivity changes. It is implemented on the Plant Data System (PDS) computer and, thus, provides rapid indication of any abnormal core conditions. The prediction algorithms use thermal-hydraulic, control rod position and neutron flux sensor information to predict the core reactivity state

  2. Providing all global energy with wind, water, and solar power, Part II: Reliability, system and transmission costs, and policies

    International Nuclear Information System (INIS)

    Delucchi, Mark A.; Jacobson, Mark Z.

    2011-01-01

    This is Part II of two papers evaluating the feasibility of providing all energy for all purposes (electric power, transportation, and heating/cooling), everywhere in the world, from wind, water, and the sun (WWS). In Part I, we described the prominent renewable energy plans that have been proposed and discussed the characteristics of WWS energy systems, the global demand for and availability of WWS energy, quantities and areas required for WWS infrastructure, and supplies of critical materials. Here, we discuss methods of addressing the variability of WWS energy to ensure that power supply reliably matches demand (including interconnecting geographically dispersed resources, using hydroelectricity, using demand-response management, storing electric power on site, over-sizing peak generation capacity and producing hydrogen with the excess, storing electric power in vehicle batteries, and forecasting weather to project energy supplies), the economics of WWS generation and transmission, the economics of WWS use in transportation, and policy measures needed to enhance the viability of a WWS system. We find that the cost of energy in a 100% WWS will be similar to the cost today. We conclude that barriers to a 100% conversion to WWS power worldwide are primarily social and political, not technological or even economic. - Research highlights: → We evaluate the feasibility of global energy supply from wind, water, and solar energy. → WWS energy can be supplied reliably and economically to all energy-use sectors. → The social cost of WWS energy generally is less than the cost of fossil-fuel energy. → Barriers to 100% WWS power worldwide are socio-political, not techno-economic.

  3. Beam shaping to provide round and square-shaped beams in optical systems of high-power lasers

    Science.gov (United States)

    Laskin, Alexander; Laskin, Vadim

    2016-05-01

    Optical systems of modern high-power lasers require control of irradiance distribution: round or square-shaped flat-top or super-Gaussian irradiance profiles are optimum for amplification in MOPA lasers and for thermal load management while pumping of crystals of solid-state ultra-short pulse lasers to control heat and minimize its impact on the laser power and beam quality while maximizing overall laser efficiency, variable profiles are also important in irradiating of photocathode of Free Electron lasers (FEL). It is suggested to solve the task of irradiance re-distribution using field mapping refractive beam shapers like piShaper. The operational principle of these devices presumes transformation of laser beam intensity from Gaussian to flat-top one with high flatness of output wavefront, saving of beam consistency, providing collimated output beam of low divergence, high transmittance, extended depth of field, negligible residual wave aberration, and achromatic design provides capability to work with ultra-short pulse lasers having broad spectrum. Using the same piShaper device it is possible to realize beams with flat-top, inverse Gauss or super Gauss irradiance distribution by simple variation of input beam diameter, and the beam shape can be round or square with soft edges. This paper will describe some design basics of refractive beam shapers of the field mapping type and optical layouts of their applying in optical systems of high-power lasers. Examples of real implementations and experimental results will be presented as well.

  4. The fractal geometry of nutrient exchange surfaces does not provide an explanation for 3/4-power metabolic scaling

    Directory of Open Access Journals (Sweden)

    Painter Page R

    2005-08-01

    Full Text Available Abstract Background A prominent theoretical explanation for 3/4-power allometric scaling of metabolism proposes that the nutrient exchange surface of capillaries has properties of a space-filling fractal. The theory assumes that nutrient exchange surface area has a fractal dimension equal to or greater than 2 and less than or equal to 3 and that the volume filled by the exchange surface area has a fractal dimension equal to or greater than 3 and less than or equal to 4. Results It is shown that contradicting predictions can be derived from the assumptions of the model. When errors in the model are corrected, it is shown to predict that metabolic rate is proportional to body mass (proportional scaling. Conclusion The presence of space-filling fractal nutrient exchange surfaces does not provide a satisfactory explanation for 3/4-power metabolic rate scaling.

  5. Automatic determination of pressurized water reactor core loading patterns which maximize end-of-cycle reactivity within power peaking and burnup constraints

    International Nuclear Information System (INIS)

    Hobson, G.H.

    1985-01-01

    An automated procedure for determining the optimal core loading pattern for a pressurized water reactor which maximizes end-of-cycle k/sub eff/ while satisfying constraints on power peaking and discharge burnup has been developed. The optimization algorithm combines a two energy group, two-dimensional coarse-mesh finite difference diffusion theory neutronics model to simulate core conditions, a perturbation theory approach to determine reactivity, flux, power and burnup changes as a function of assembly shuffling, and Monte Carlo integer programming to select the optimal loading pattern solution. The core examined was a typical Cycle 2 reload with no burnable poisons. Results indicate that the core loading pattern that maximizes end-of-cycle k/sub eff/ results in a 5.4% decrease in fuel cycle costs compared with the core loading pattern that minimizes the maximum relative radial power peak

  6. VAr reserve concept applied to a wind power plant

    DEFF Research Database (Denmark)

    Martinez, Jorge; Kjær, Philip C.; Rodriguez, Pedro

    2011-01-01

    to wind power plants. This paper proposes two different VAr reserve control strategies for a wind power plant. The amount of dynamic VAr available most of the operation time, makes the wind power plant (WPP) a good candidate to include a VAr reserve management system. Two different ways of implementing...... a VAr management system are proposed and analyzed. Such a reactive power reserve may be provided by the wind power plant since the amount of reactive power installed for most active power working points exceeds the demand required by the grid operator. Basically, this overrated reactive power capacity...... is a consequence of sizing wind turbine facilities for maximum active power level. The reactive power losses, due to active power transportation inside the plant (normally two transformers), and P-Q wind turbine characteristics define the P-Q reserve chart. By utilizing the intrinsic overrated reactive power...

  7. Two-layer optimization methodology for wind distributed generation planning considering plug-in electric vehicles uncertainty: A flexible active-reactive power approach

    International Nuclear Information System (INIS)

    Ahmadian, Ali; Sedghi, Mahdi; Aliakbar-Golkar, Masoud; Fowler, Michael; Elkamel, Ali

    2016-01-01

    Highlights: • Flexible active-reactive power control of WDGs is proposed for WDGs planning. • The uncertainty of PEVs effect is considered in WDGs planning. • The wind data is classified in four separate seasons to reach more accurate results. • The PSO algorithm is modified to overcome the complexity of problem. - Abstract: With increasing the penetration of wind power, the voltage regulation becomes a more important problem in active distribution networks. In addition, as an uncertain load Plug-in Electric Vehicles (PEVs) will introduce a new concern in voltage adjustment of future distribution networks. Hence, this paper presents a flexible active-reactive power based Wind Distributed Generation (WDG) planning procedure to address the mentioned challenges. The uncertainties related to WDGs, load demand as well as PEVs load have been handled using the Point Estimate Method (PEM). The distribution network under study is equipped to on-load tap-changer and, as a conventional voltage control component, the Capacitor Banks (CBs) will be planned simultaneously with WDGs. The planning procedure has been considered as a two-loop optimization problem that is solved using Particle Swarm Optimization (PSO) and Tabu Search (TS) algorithms. The tap position and power factor of WDGs are taken into account as stochastic variables with practical limitations. The proposed methodology is applied to a typical distribution network and several scenarios are considered and analyzed. Simulation results show that the standard deviation of power factor depends on PEVs penetration that highlights the capability curve of WDGs. The optimal penetration of wind power increases nonlinearly versus increasing of PEVs connected to the distribution network, however the fixed CBs are required to increase the optimal penetration of WDGs. The proposed Modified PSO (MPSO) is compared with the conventional PSO in numerical studies that show MPSO is more efficient than the conventional

  8. A Comprehensive Strategy for Accurate Reactive Power Distribution, Stability Improvement, and Harmonic Suppression of Multi-Inverter-Based Micro-Grid

    Directory of Open Access Journals (Sweden)

    Henan Dong

    2018-03-01

    Full Text Available Among the issues of accurate power distribution, stability improvement, and harmonic suppression in micro-grid, each has been well studied as an individual, and most of the strategies about these issues aim at one inverter-based micro-grid, hence there is a need to establish a model to achieve these functions as a whole, aiming at a multi-inverter-based micro-grid. This paper proposes a comprehensive strategy which achieves this goal successfully; since the output voltage and frequency of micro-grid all consist of fundamental and harmonic components, the strategy contains two parts accordingly. On one hand, a fundamental control strategy is proposed upon the conventional droop control. The virtual impedance is introduced to solve the problem of accurate allocation of reactive power between inverters. Meanwhile, a secondary power balance controller is added to improve the stability of voltage and frequency while considering the aggravating problem of stability because of introducing virtual impedance. On the other hand, the fractional frequency harmonic control strategy is proposed. It can solve the influence of nonlinear loads, micro-grid inverters, and the distribution network on output voltage of inverters, which is focused on eliminating specific harmonics caused by the nonlinear loads, micro-grid converters, and the distribution network so that the power quality of micro-grid can be improved effectively. Finally, small signal analysis is used to analyze the stability of the multi-converter parallel system after introducing the whole control strategy. The simulation results show that the strategy proposed in this paper has a great performance on distributing reactive power, regulating and stabilizing output voltage of inverters and frequency, eliminating harmonic components, and improving the power quality of multi-inverter-based micro-grid.

  9. Novel Control Strategy for Multiple Run-of-the-River Hydro Power Plants to Provide Grid Ancillary Services

    Energy Technology Data Exchange (ETDEWEB)

    Mohanpurkar, Manish; Luo, Yusheng; Hovsapian, Rob; Muljadi, Eduard; Gevorgian, Vahan; Koritarov, Vladimir

    2017-05-01

    Electricity generated by Hydropower Plants (HPPs) contributes a considerable portion of bulk electricity generation and delivers it with a low carbon footprint. In fact, HPP electricity generation provides the largest share from renewable energy resources, which includes solar and wind energy. The increasing penetration of wind and solar penetration leads to a lowered inertia in the grid and hence poses stability challenges. In recent years, breakthrough in energy storage technologies have demonstrated the economic and technical feasibility of extensive deployments in power grids. Multiple ROR HPPs if integrated with scalable, multi time-step energy storage so that the total output can be controlled. Although, the size of a single energy storage is far smaller than that of a typical reservoir, cohesively managing multiple sets of energy storage distributed in different locations is proposed. The ratings of storages and multiple ROR HPPs approximately equals the rating of a large, conventional HPP. The challenges associated with the system architecture and operation are described. Energy storage technologies such as supercapacitors, flywheels, batteries etc. can function as a dispatchable synthetic reservoir with a scalable size of energy storage will be integrated. Supercapacitors, flywheels, and battery are chosen to provide fast, medium, and slow responses to support grid requirements. Various dynamic and transient power grid conditions are simulated and performances of integrated ROR HPPs with energy storage is provided. The end goal of this research is to investigate the inertial equivalence of a large, conventional HPP with a unique set of multiple ROR HPPs and optimally rated energy storage systems.

  10. Compensación de potencia reactiva mediante bancos asimétricos de capacitores; Reactive Power Compensation by Unbalanced Capacitor Banks

    Directory of Open Access Journals (Sweden)

    Ignacio Pérez Abril

    2011-02-01

    Full Text Available A pesar de que los sistemas de distribución primaria y secundaria son desbalanceados por naturaleza, lacompensación de potencia reactiva en estos sistemas, se realiza comúnmente mediante bancos decondensadores trifásicos balanceados. En este trabajo se presenta la formulación general para el problemade compensación de potencia reactiva en sistemas desbalanceados mediante bancos de condensadoresdesbalanceados. Se presentan cuatro ejemplos de compensación en el secundario de bancos desbalanceadosde transformadores monofásicos. Todos los ejemplos muestran que la compensación por bancosdesbalanceados de capacitores incrementa los beneficios con respecto al uso de bancos balanceados  In spite of the fact that primary and secondary distribution systems are unbalanced by nature, thereactive power compensation on these systems is commonly developed by the use of balanced capacitorbanks. In this paper, the general formulation for the reactive power compensation problem onunbalanced systems with unbalanced capacitor banks is developed. Four examples of reactive powercompensation on the secondary of unbalanced three-phase transformers banks are presented. All theexamples show that the compensation by unbalanced capacitor banks increases the active power lossessaving as well as reduce the transformer’s load and contributes to balance the line currents when the loadis unbalanced.

  11. Cost on Reliability and Production Loss for Power Converters in the Doubly Fed Induction Generator to Support Modern Grid Codes

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Lau, Mogens

    2016-01-01

    As wind farms are normally located in remote areas, many grid codes have been issued especially related to the reactive power support. Although the Doubly-Fed Induction Generator (DFIG) based power converter is able to control the active power and reactive power independently, the effects...... of providing reactive power on the lifetime of the power converter and the cost-of-energy of the whole system are seldom evaluated, even though it is an important topic. In this paper, the loss models of the DFIG system are established at various conditions of the reactive power injection. If the mission...... profile is taken into account, the lifespan of the power semiconductors as well as the cost of the reactive power can be calculated. It is concluded that an over-excited reactive power injection significantly reduces the power converter lifetime, only 1/4 of the case that there is no reactive power...

  12. DC microgrids with energy storage systems and demand response for providing support to frequency regulation of electrical power systems

    DEFF Research Database (Denmark)

    Basic, Hrvoje; Dragicevic, Tomislav; Pandzic, Hrvoje

    2017-01-01

    Frequency regulation of electric power systems efficiency depends on response time and on power reserves for frequency regulation. As integration of non-dispatchable renewable generation in the power system results with increased need for power reserves from fast responding power units, the idea ...

  13. Active and Reactive Power Control Strategy for Grid-Connected Six-Phase Generator by Using Multi-Modular Matrix Converters

    Directory of Open Access Journals (Sweden)

    David Caballero

    2016-12-01

    Full Text Available This paper proposes an active and reactive power control strategy based on predictive control approaches applied to gridconnected renewable energy systems. To accomplish this a multi-modular matrix converter topologies are used in combination with a simple but efficient grid synchronization strategy. The theoretical performance analysis is performed considering a six-phase wind energy generator system interconnected with the grid. Results based on a MATLAB/Simulink simulation environment are discussed and the most relevant characteristics of the proposed control technique are highlighted considering the total harmonic distortion and the mean squared error as a parameters of performance.

  14. Economic opportunities resulting from a global deployment of concentrated solar power (CSP) technologies-The example of German technology providers

    International Nuclear Information System (INIS)

    Vallentin, Daniel; Viebahn, Peter

    2010-01-01

    Several energy scenario studies consider concentrated solar power (CSP) plants as an important technology option to reduce the world's CO 2 emissions to a level required for not letting the global average temperature exceed a threshold of 2-2.4 o C. A global ramp up of CSP technologies offers great economic opportunities for technology providers as CSP technologies include highly specialised components. This paper analyses possible value creation effects resulting from a global deployment of CSP until 2050 as projected in scenarios of the International Energy Agency (IEA) and Greenpeace International. The analysis focuses on the economic opportunities of German technology providers since companies such as Schott Solar, Flabeg or Solar Millennium are among the leading suppliers of CSP technologies on the global market.

  15. An Active Power Filter Based on a Three-Level Inverter and 3D-SVPWM for Selective Harmonic and Reactive Compensation

    Directory of Open Access Journals (Sweden)

    José Luis Monroy-Morales

    2017-03-01

    Full Text Available Active Power Filters (APFs have been used for reducing waveform distortion and improving power quality. However, this function can be improved by means of a selective harmonic compensation. Since an APF has rating restrictions, it is convenient to have the option of selecting an individual or a set of particular harmonics in order to compensate and apply the total APF capabilities to eliminate these harmonics, in particular those with a greater impact on the Total Harmonic Distortion (THD. This paper presents the development of a new APF prototype based on a three-phase three-level Neutral Point Clamped (NPC inverter with selective harmonic compensation capabilities and reactive power compensation. The selective harmonic compensation approach uses several Synchronous Rotating Frames (SRF, to detect and control individual or a set of harmonics using d and q variables. The APF includes a Three-Dimensional Space Vector Modulator (3D-SVPWM in order to generate the compensation currents. Because of its multilevel topology, the proposed active power filter can be used in diverse power quality applications at sub-transmission and distribution voltage levels. Simulation and experimental results are shown to validate the proposed solution and assess the prototype performance in different scenarios.

  16. Sampling strategies and materials for investigating large reactive particle complaints from Valley Village homeowners near a coal-fired power plant

    International Nuclear Information System (INIS)

    Chang, A.; Davis, H.; Frazar, B.; Haines, B.

    1997-01-01

    This paper will present Phase 3's sampling strategies, techniques, methods and substrates for assisting the District to resolve the complaints involving yellowish-brown staining and spotting of homes, cars, etc. These spots could not be easily washed off and some were permanent. The sampling strategies for the three phases were based on Phase 1 -- the identification of the reactive particles conducted in October, 1989 by APCD and IITRI, Phase 2 -- a study of the size distribution and concentration as a function of distance and direction of reactive particle deposition conducted by Radian and LG and E, and Phase 3 -- the determination of the frequency of soiling events over a full year's duration conducted in 1995 by APCD and IITRI. The sampling methods included two primary substrates -- ACE sheets and painted steel, and four secondary substrates -- mailbox, aluminum siding, painted wood panels and roof tiles. The secondary substrates were the main objects from the Valley Village complaints. The sampling technique included five Valley Village (VV) soiling/staining assessment sites and one southwest of the power plant as background/upwind site. The five VV sites northeast of the power plant covered 50 degrees span sector and 3/4 miles distance from the stacks. Hourly meteorological data for wind speeds and wind directions were collected. Based on this sampling technique, there were fifteen staining episodes detected. Nine of them were in summer, 1995

  17. ROSMETER: a bioinformatic tool for the identification of transcriptomic imprints related to reactive oxygen species type and origin provides new insights into stress responses.

    Science.gov (United States)

    Rosenwasser, Shilo; Fluhr, Robert; Joshi, Janak Raj; Leviatan, Noam; Sela, Noa; Hetzroni, Amotz; Friedman, Haya

    2013-10-01

    The chemical identity of the reactive oxygen species (ROS) and its subcellular origin will leave a specific imprint on the transcriptome response. In order to facilitate the appreciation of ROS signaling, we developed a tool that is tuned to qualify this imprint. Transcriptome data from experiments in Arabidopsis (Arabidopsis thaliana) for which the ROS type and organelle origin are known were compiled into indices and made accessible by a Web-based interface called ROSMETER. The ROSMETER algorithm uses a vector-based algorithm to portray the ROS signature for a given transcriptome. The ROSMETER platform was applied to identify the ROS signatures profiles in transcriptomes of senescing plants and of those exposed to abiotic and biotic stresses. An unexpected highly significant ROS transcriptome signature of mitochondrial stress was detected during the early presymptomatic stages of leaf senescence, which was accompanied by the specific oxidation of mitochondria-targeted redox-sensitive green fluorescent protein probe. The ROSMETER analysis of diverse stresses revealed both commonalties and prominent differences between various abiotic stress conditions, such as salt, cold, ultraviolet light, drought, heat, and pathogens. Interestingly, early responses to the various abiotic stresses clustered together, independent of later responses, and exhibited negative correlations to several ROS indices. In general, the ROS transcriptome signature of abiotic stresses showed limited correlation to a few indices, while biotic stresses showed broad correlation with multiple indices. The ROSMETER platform can assist in formulating hypotheses to delineate the role of ROS in plant acclimation to environmental stress conditions and to elucidate the molecular mechanisms of the oxidative stress response in plants.

  18. A combined usage of stochastic and quantitative risk assessment methods in the worksites: Application on an electric power provider

    International Nuclear Information System (INIS)

    Marhavilas, P.K.; Koulouriotis, D.E.

    2012-01-01

    An individual method cannot build either a realistic forecasting model or a risk assessment process in the worksites, and future perspectives should focus on the combined forecasting/estimation approach. The main purpose of this paper is to gain insight into a risk prediction and estimation methodological framework, using the combination of three different methods, including the proportional quantitative-risk-assessment technique (PRAT), the time-series stochastic process (TSP), and the method of estimating the societal-risk (SRE) by F–N curves. In order to prove the usefulness of the combined usage of stochastic and quantitative risk assessment methods, an application on an electric power provider industry is presented to, using empirical data.

  19. Method of controlling reactivity

    International Nuclear Information System (INIS)

    Tochihara, Hiroshi.

    1982-01-01

    Purpose: To improve the reactivity controlling characteristics by artificially controlling the leakage of neutron from a reactor and providing a controller for controlling the reactivity. Method: A reactor core is divided into several water gaps to increase the leakage of neutron, its reactivity is reduced, a gas-filled control rod or a fuel assembly is inserted into the gap as required, the entire core is coupled in a system to reduce the leakage of the neutron, and the reactivity is increased. The reactor shutdown is conducted by the conventional control rod, and to maintain critical state, boron density varying system is used together. Futher, a control rod drive is used with that similar to the conventional one, thereby enabling fast reactivity variation, and the positive reactivity can be obtained by the insertion, thereby improving the reactivity controlling characteristics. (Yoshihara, H.)

  20. Measuring Memory Reactivation With Functional MRI: Implications for Psychological Theory.

    Science.gov (United States)

    Levy, Benjamin J; Wagner, Anthony D

    2013-01-01

    Environmental cues often remind us of earlier experiences by triggering the reactivation of memories of events past. Recent evidence suggests that memory reactivation can be observed using functional MRI and that distributed pattern analyses can even provide evidence of reactivation on individual trials. The ability to measure memory reactivation offers unique and powerful leverage on theoretical issues of long-standing interest in cognitive psychology, providing a means to address questions that have proven difficult to answer with behavioral data alone. In this article, we consider three instances. First, reactivation measures can indicate whether memory-based inferences (i.e., generalization) arise through the encoding of integrated cross-event representations or through the flexible expression of separable event memories. Second, online measures of memory reactivation may inform theories of forgetting by providing information about when competing memories are reactivated during competitive retrieval situations. Finally, neural reactivation may provide a window onto the role of replay in memory consolidation. The ability to track memory reactivation, including at the individual trial level, provides unique leverage that is not afforded by behavioral measures and thus promises to shed light on such varied topics as generalization, integration, forgetting, and consolidation. © The Author(s) 2013.

  1. Export of reactive nitrogen from coal-fired power plants in the U.S.: Estimates from a plume-in-grid modeling study - article no. D04308

    Energy Technology Data Exchange (ETDEWEB)

    Vijayaraghavan, K.; Zhang, Y.; Seigneur, C.; Karamchandani, P.; Snell, H.E.

    2009-02-15

    The export of reactive nitrogen (nitrogen oxides and their oxidation products, collectively referred to as NOy) from coal-fired power plants in the U.S. to the rest of the world could have a significant global contribution to ozone. Traditional Eulerian gridded air quality models cannot characterize accurately the chemistry and transport of plumes from elevated point sources such as power plant stacks. A state-of-the-science plume-in-grid (PinG) air quality model, a reactive plume model embedded in an Eulerian gridded model, is used to estimate the export of NOy from 25 large coal-fired power plants in the U. S. (in terms of NOx and SO{sub 2} emissions) in July 2001 to the global atmosphere. The PinG model used is the Community Multiscale Air Quality Model with Advanced Plume Treatment (CMAQ-APT). A benchmark simulation with only the gridded model, CMAQ, is also conducted for comparison purposes. The simulations with and without advanced plume treatment show differences in the calculated export of NOy from the 25 plants considered reflecting the effect of using a detailed and explicit treatment of plume transport and chemistry. The advanced plume treatment results in 31% greater simulated export of NOy compared to the purely grid-based modeling approach. The export efficiency of NOy (the fraction of NOy emitted that is exported) is predicted to be 21% without APT and 27% with APT. When considering only export through the eastern boundary across the Atlantic, CMAQ-APT predicts that the export efficiency is 24% and that 2% of NOy is exported as NOx, 49% as inorganic nitrate, and 25% as PAN. These results are in reasonably good agreement with an analysis reported in the literature of aircraft measurements over the North Atlantic.

  2. Recovery Act: Demonstration of a SOFC Generator Fueled by Propane to Provide Electrical Power to Real World Applications

    Energy Technology Data Exchange (ETDEWEB)

    Bessette, Norman [Acumentrics Corporation, Westwood, MA (United States)

    2016-08-01

    The objective of this project provided with funds through the American Recovery and Reinvestment Act of 2009 (ARRA) was to demonstrate a Solid Oxide Fuel Cell (SOFC) generator capable of operation on propane fuel to improve efficiency and reduce emissions over commercially available portable generators. The key objectives can be summarized as: Development of two portable electrical generators in the 1-3kW range utilizing Solid Oxide Fuel Cells and propane fuel; The development and demonstration of a proof-of-concept electro-mechanical propane fuel interface that provides a user friendly capability for managing propane fuel; The deployment and use of the fuel cell portable generators to power media production equipment over the course of several months at multiple NASCAR automobile racing events; The deployment and use of the fuel cell portable generators at scheduled events by first responders (police, fire) of the City of Folsom California; and Capturing data with regard to the systems’ ability to meet Department of Energy (DOE) Technical Targets and evaluating the ease of use and potential barriers to further adoption of the systems.

  3. Fourier power, subjective distance, and object categories all provide plausible models of BOLD responses in scene-selective visual areas

    Science.gov (United States)

    Lescroart, Mark D.; Stansbury, Dustin E.; Gallant, Jack L.

    2015-01-01

    Perception of natural visual scenes activates several functional areas in the human brain, including the Parahippocampal Place Area (PPA), Retrosplenial Complex (RSC), and the Occipital Place Area (OPA). It is currently unclear what specific scene-related features are represented in these areas. Previous studies have suggested that PPA, RSC, and/or OPA might represent at least three qualitatively different classes of features: (1) 2D features related to Fourier power; (2) 3D spatial features such as the distance to objects in a scene; or (3) abstract features such as the categories of objects in a scene. To determine which of these hypotheses best describes the visual representation in scene-selective areas, we applied voxel-wise modeling (VM) to BOLD fMRI responses elicited by a set of 1386 images of natural scenes. VM provides an efficient method for testing competing hypotheses by comparing predictions of brain activity based on encoding models that instantiate each hypothesis. Here we evaluated three different encoding models that instantiate each of the three hypotheses listed above. We used linear regression to fit each encoding model to the fMRI data recorded from each voxel, and we evaluated each fit model by estimating the amount of variance it predicted in a withheld portion of the data set. We found that voxel-wise models based on Fourier power or the subjective distance to objects in each scene predicted much of the variance predicted by a model based on object categories. Furthermore, the response variance explained by these three models is largely shared, and the individual models explain little unique variance in responses. Based on an evaluation of previous studies and the data we present here, we conclude that there is currently no good basis to favor any one of the three alternative hypotheses about visual representation in scene-selective areas. We offer suggestions for further studies that may help resolve this issue. PMID:26594164

  4. Analysis of the reactive power consumption and the harmonics in the network by the non-linear electrical loads

    Energy Technology Data Exchange (ETDEWEB)

    Cogo, Joao Roberto [Escola Federal de Engenharia de Itajuba, MG (Brazil)

    1994-12-31

    The non linear electrical loads can give rise to a number of disturbances in electrical power networks. Among them, the high consumption of relative power is to be noted and so is the several harmonic components which may be injected in the industry system and very often in the utility system. So, by using appropriate technical considerations, as well as measurements in typical special electrical loads, such negative effects are analyzed and ways of minimizing them are suggested. (author) 3 refs., 11 figs., 6 tabs.

  5. Non-Model-Based Control of a Wheeled Vehicle Pulling Two Trailers to Provide Early Powered Mobility and Driving Experiences.

    Science.gov (United States)

    Sanders Td Vr, David A

    2018-01-01

    Non-model-based control of a wheeled vehicle pulling two trailers is proposed. It is a fun train for disabled children consisting of a locomotive and two carriages. The fun train has afforded opportunities for both disabled and able bodied young people to share an activity and has provided early driving experiences for disabled children; it has introduced them to assistive and powered mobility. The train is a nonlinear system and subject to nonholonomic kinematic constraints, so that position and state depend on the path taken to get there. The train is described, and then, a robust control algorithm using proportional-derivative filtered errors is proposed to control the locomotive. The controller was not dependent on an accurate model of the train, because the mass of the vehicle and two carriages changed depending on the number, size, and shape of children and wheelchair seats on the train. The controller was robust and stable in uncertainty. Results are presented to show the effectiveness of the approach, and the suggested control algorithm is shown to be acceptable without knowing the exact plant dynamics.

  6. Changes in reactivity and in the margins to thermal limits by the inclusion of control rods of advanced type in the Laguna Verde Power plant

    International Nuclear Information System (INIS)

    Hernandez, J.L.; Perusquia, R.; Montes, J.L.; Ortiz, J.J.; Ramirez, J.R.

    2004-01-01

    The obtained results are presented when simulating with CM-PRESTO code the cycle 10 of the unit 1 of the Laguna Verde Central, using two advanced types of control bars, besides the originally loaded ones. The two advanced types, to those that are denominated 1AV and 2AV in this work, are of different design, however both have in some place of the bar, a section with hafnium like neutron absorber material. They thought about three different scenarios, in the first one, used as reference, is simulated the cycle 10 using the original control bars, while in the other two cases the advanced types are used. The values of the reactivity were compared and of some margins to the thermal limits obtained when using the bars of advanced type, with those obtained in the case in that alone they are considered those original bars. It was found that in condition of power both advanced types present bigger absorber power of neutrons that the original bars, being quantified in average this bigger power in 0.22 pcm/notch for the type 1AV and in 0.51 pcm/notch for the type 2AV. The affectation of the margins to the observed thermal limits is minimum. (Author)

  7. Influence of reactive oxygen species during deposition of iron oxide films by high power impulse magnetron sputtering

    Czech Academy of Sciences Publication Activity Database

    Straňák, V.; Hubička, Zdeněk; Čada, Martin; Bogdanowicz, R.; Wulff, H.; Helm, C.A.; Hippler, R.

    2018-01-01

    Roč. 51, č. 9 (2018), s. 1-12, č. článku 095205. ISSN 0022-3727 R&D Projects: GA ČR GA17-08389S Institutional support: RVO:68378271 Keywords : high power impulse magnetron sputtering (HiPIMS) * iron oxide thin films * wüstite * magnetite * maghemite * hematite Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics ) Impact factor: 2.588, year: 2016

  8. Integrated firewood production, ensures fuel security for self sustaining Biomass Power Plants reduces agricultural cost and provides livestock production

    International Nuclear Information System (INIS)

    Lim, Andre

    2010-01-01

    Growing concerns on the impact of climate change, constraints on fossil fuel electricity generation and the likelihood of oil depletion is driving unprecedented growth and investment in renewable energy across the world. The consistency of biomass power plants makes them capable of replacing coal and nuclear for base-load. However experience had shown otherwise, climate change reduces yields, uncontrolled approvals for biomass boilers increased demands and at times motivated by greedy farmers have raised price of otherwise a problematic agricultural waste to high secondary income stream forcing disruption to fuel supply to power plants and even their shutting down. The solution is to established secured fuel sources, fortunately in Asia there are several species of trees that are fast growing and have sufficient yields to make their harvesting economically viable for power production. (author)

  9. Operating characteristics of a single-stage Stirling cryocooler capable of providing 700 W cooling power at 77 K

    Science.gov (United States)

    Xu, Ya; Sun, Daming; Qiao, Xin; Yu, Yan S. W.; Zhang, Ning; Zhang, Jie; Cai, Yachao

    2017-04-01

    High cooling capacity Stirling cryocooler generally has hundreds to thousands watts of cooling power at liquid nitrogen temperature. It is promising in boil-off gas (BOG) recondensation and high temperature superconducting (HTS) applications. A high cooling capacity Stirling cryocooler driven by a crank-rod mechanism was developed and studied systematically. The pressure and frequency characteristics of the cryocooler, the heat rejection from the ambient heat exchanger, and the cooling performance are studied under different charging pressure. Energy conversion and distribution in the cryocooler are analyzed theoretically. With an electric input power of 10.9 kW and a rotating speed of 1450 r/min of the motor, a cooling power of 700 W at 77 K and a relative Carnot efficiency of 18.2% of the cryocooler have been achieved in the present study, and the corresponding pressure ratio in the compression space reaches 2.46.

  10. Reactivity estimation during a reactivity-initiated accident using the extended Kalman filter

    International Nuclear Information System (INIS)

    Busquim e Silva, R.; Marques, A.L.F.; Cruz, J.J.; Shirvan, K.; Kazimi, M.S.

    2015-01-01

    Highlights: • The EKF is modeled using sophisticate strategies to make the algorithm robust and accurate. • For a supercritical reactor under RIA, the EKF presents better results compared to IPK method independent of magnitude of the noise loads. • A sensitivity for five distinct carry-over effects indicates that the EKF is less sensitive to the different set of noise. • Although the P3D/R5 simulates the reactivity using a spatial kinetics method, the use of PKRE to model the EKF provides accurate results. • The reactivity’s standard deviation is higher for the IKF method. • Under HZP (slow power response) the IPK reactivity varies widely from positive to negative values (add extra difficulty to controlling the supercritical reactor): the EKF method does not have similar behavior under the same conditions (better controlling the operation). - Abstract: This study implements the extended Kalman filter (EKF) to estimate the nuclear reactor reactivity behavior under a reactivity-initiated accident (RIA). A coupled neutronics/thermal hydraulics code PARCS/RELAP5 (P3D/R5) simulates a control rod assembly ejection (CRE) on a traditional 2272 MWt PWR to generate the reactor power profile. A MATLAB script adds random noise to the simulated reactor power. For comparison, the inverse point kinetics (IPK) deterministic method is also implemented. Three different cases of CRE are simulated and the EKF, IPK and the P3D/R5 reactivity are compared. It was found that the EKF method presents better results compared to the IPK method. Furthermore, under a RIA due to small reactivity insertion and slow power response, the IPK reactivity varies widely from positive to negative, which may add extra difficulty to the task of controlling a supercritical reactor. This feature is also confirmed by a sensitivity analysis for five different noise loads and three distinct noise measurements standard deviations (SD)

  11. Star Power: Providing for the Gifted & Talented. Module 4. Applications of Theories of Creativity to the Gifted/Talented.

    Science.gov (United States)

    Heinemann, Alison; Mallis, Jackie

    The document presents Module 4, applications of theories of creativity to the gifted/talented, of the Star Power modules developed for school personnel who have an interest in or a need to explore the area of gifted and talented education. It is explained in an introductory section that the modules can be used for independent study, for small…

  12. Star Power: Providing for the Gifted & Talented. Module 10. Guidance and Counseling for the Gifted/Talented.

    Science.gov (United States)

    Heinemann, Alison; Mallis, Jackie

    The document presents Module 10, guidance and counseling for the gifted/talented, of the Star Power modules developed for school personnel who have an interest in or a need to explore the area of gifted and talented education. It is explained in an introductory section that the module can be used for independent study, for small group interaction,…

  13. Star Power: Providing for the Gifted & Talented. Module 3. Applications of Theories of Intelligence to the Gifted/Talented.

    Science.gov (United States)

    Heinemann, Alison; Mallis, Jackie

    The document presents Module 3, applications of theories of intelligence to the gifted/talented, of the Star Power modules developed for school personnel who have an interest in or a need to explore the area of gifted and talented education. It is explained in an introductory section that the modules can be used for independent study, for small…

  14. 77 FR 24941 - Vantage Wind Energy LLC; Order Accepting Updated Market Power Analysis and Providing Direction on...

    Science.gov (United States)

    2012-04-26

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER10-956-003] Vantage Wind.... 1. In this order, the Commission accepts an updated market power analysis filed by Vantage Wind Energy LLC (Vantage Wind). As discussed below, the Commission concludes that Vantage Wind continues to...

  15. Digital reactivity meter

    International Nuclear Information System (INIS)

    Jiang Zongbing

    1996-02-01

    The importance and the usual methods of reactivity measurement in a nuclear reactor are presented. Emphasis is put upon the calculation principle, software and hardware components, main specifications, application, as well as the features of the digital reactivity meter. The test results of operation in various reactors shown that the meter possess the following features: high accuracy, short response time, low output noise, high resolution, wide measuring range, simple and flexible to operate, high stability and reliability. In addition, the reactivity meter can save the measuring data automatically and have a perfect capability of self-verifying. It not only meet the requirement of the reactivity measurement in nuclear power plant, but also can be applied to various types of reactors. (1 tab.)

  16. Fuel reactivity and release of pollutants and alkali vapours in pressurized combustion for combined cycle power generation

    Energy Technology Data Exchange (ETDEWEB)

    Aho, M.; Haemaelaeinen, J.; Paakkinen, K.; Rantanen, J. [VTT Energy, Jyvaeskylae (Finland); Hernberg, R.; Haeyrinen, V.; Joutsenoja, T. [Tampere Univ. of Technology (Finland). Lab. of Plasma Technology

    1996-12-01

    This project forms a part of the overall Pressurized Power Coal Combustion Project Area (PPFC) which aims at an assessment of the viability and technical merits of pressurized pulverized coal combustion, in an atmosphere of recycled flue gas and oxygen in a coordinated and harmonized programme. The objective of the research at Technical Research Centre of Finland (VTT) and Tampere University of Technology (TUT) is aimed at determining the consequences of solid fuel burning in a mixture of oxygen and recycled flue gases. Combustion conditions of a pressurized entrained flow of pulverized coal and char particles in PEFR are determined with high precision. The effects of experimental parameters on the formation of nitrogen oxides (N{sub 2}O, NO and NO{sub 2}) and gaseous alkali compounds (indicated as NaX(g) and KX(g)) are studied. An effective on-line analysis method for vaporised Na and K compounds was developed. The dependency between particle temperatures and the vaporisation of Na and K was measured with three coals. The results show that alkali removal before gas turbines is always necessary with these coals if combusted in combined cycles. Pressure decreases the formation of NO and has usually no clear effect on the formation of N{sub 2}O. The order of NO/N{sub 2}O ratios correspond to fuel-O/fuel-N ratios. Increase of PO{sub 2} (oxygen concentration) of combustion gas increases the formation of NO{sub 2}. Remarkable concentrations of NO{sub 2} were often measured at high PO{sub 2} at 800-850 deg C. Therefore, NO{sub 2} should be measured from pressurized fluidized bed reactors. Some trends of the formation of NO{sub 2} with coal differ clearly from those with its parent char: N{sub 2}O formation is not strongly temperature dependent with char, and the concentrations of N{sub 2}O formed from char are much lower than those of coal. PO{sub 2} does not effect on the formation of NO from char in the studied range

  17. Use mobile pumps and liquid chilling water units to provide chilled water for nuclear reactor during nuclear power plant accident

    International Nuclear Information System (INIS)

    Zhang Guobin; Feng Jiaxuan

    2012-01-01

    From the nuclear accident in Japan Fuksuhima in March this year, despite a shut down of the reactor, the residue heat inside the reactor was not able to remove due to the failure of the cooling system and it finally caused the catastrophe. It was observed that when the failure of the cooling system after an earthquake of magnitude 9 and a tsunami of 28 meters height, the containment vessel for the reactor core was still able to maintain its integrity in the first 24 hours before the first explosion was happened. A backup emergency heat removal system for nuclear power plants using mo- bile pumps and liquid chilling units has been proposed 20 years ago by Cheung [Ref. 1]. Due to the fact that there are more than 400 nuclear power plants around the world and 10% of them are located in earthquake active zone, together with the aging of some of the power plants which were built more than 30 years ago, the risk of another nuclear accident becomes high. An emergency safety measure has to be designed in order to deal with the unforeseen scenario. This re- port re-visits the proposal again; to re-design to the suit the need and to integrate with the current situation of the nuclear industry. (authors)

  18. A digital real-time reactivity meter for PFR

    International Nuclear Information System (INIS)

    McWilliams, D.

    1975-08-01

    A digital reactivity meter has been prpduced which is believed to constitute a significant advance over others reported in the literature. The main advantage of this system is its versatility which is brought about by the high degree of interactive operator control which is provided. The reactivity and power are continuously displayed in both graphical and alpha-numeric form on a TV-type of display unit. Data output is by means of an incremental graph plotter, a typewriter, or a high speed paper tape punch. The system has been extensively tested on the Prototype Fast Reactor at Dounreay and is now the standard reactivity measuring method for reactor experiments there. (author)

  19. Reactivity costs in MARIA reactor

    International Nuclear Information System (INIS)

    Marcinkowska, Zuzanna E.; Pytel, Krzysztof M.; Frydrysiak, Andrzej

    2017-01-01

    Highlights: • The methodology for calculating consumed fuel cost of excess reactivity is proposed. • Correlation between time integral of the core excess reactivity and released energy. • Reactivity price gives number of fuel elements required for given excess reactivity. - Abstract: For the reactor operation at high power level and carrying out experiments and irradiations the major cost of reactor operation is the expense of nuclear fuel. In this paper the methodology for calculating consumed fuel cost-relatedness of excess reactivity is proposed. Reactivity costs have been determined on the basis of operating data. A number of examples of calculating the reactivity costs for processes such as: strong absorbing material irradiation, molybdenium-99 production, beryllium matrix poisoning and increased moderator temperature illustrates proposed method.

  20. International Economic Association on organization of co-operative production and development of equipment and providing technical assistance in construction of nuclear power plants - ''INTERATOMENERGO''

    International Nuclear Information System (INIS)

    Mal'tsev, N.D.

    1979-01-01

    History is stated of foundation of the International Economic Association ''Interatomenergo''. Structure is given of the Association and the list of main problems to be solved by it. Project is given of the programm of co-operation in the field of scientific and technical works as well as of design and projecting works in creation of new types of equipment for nuclear power plants, in particular, creation of serial power units with improved WWER-1000 reactor. Directions are stated of activity of the Association in the field of providing assistance in construction and exploitation of nuclear power plants as well as in training of operational personnel [ru

  1. Compensación de potencia reactiva en sistemas desbalanceados utilizando algoritmos genéticos Reactive power compensation in unbalanced systems using genetic algorithms

    Directory of Open Access Journals (Sweden)

    Davel Borges Vasconcellos

    2012-12-01

    Full Text Available La eficiencia energética de un sistema eléctrico depende en gran medida del factor de potencia con que opera y de una eficaz compensación de potencia reactiva si esta es necesaria. Una de las vías más utilizadas para efectuar la compensación del reactivo es el empleo de bancos de capacitores. La óptima aplicación de estos presupone tres aspectos: la selección de la capacidad más adecuada de los bancos, el tipo de compensador a utilizar, fijo o variable, así como la ubicación en el sistema de suministro eléctrico. En determinadas publicaciones, estos aspectos se tratan de forma independiente. Sin embargo, desde el punto de vista técnico ellos están mutuamente vinculados y todos poseen una implicación económica, lo que obliga a la necesidad de considerarlos en conjunto para un problema de optimización dado. Existen referencias de otros trabajos que desarrollan métodos que consideran estos aspectos de manera conjunta, pero presentan limitantes para ser aplicados en los sistemas de suministro eléctrico del sector terciario y donde predominan condiciones de desbalance. En este trabajo se presenta un método con el empleo de los algoritmos genéticos que posibilita una formulación más exacta del problema arrojando soluciones de mayor calidad. El programa desarrollado se soporta sobre software MATLAB, versión 7.8 (R2009a, utilizando las estructuras de programación de Genetic Algorithm and Direct Search Toolbox. La efectividad de su aplicación se muestra en casos de estudio correspondientes a sistemas de suministro eléctrico de dos hoteles pertenecientes al sector terciario en la provincia de Camagüey, Cuba.The energy efficiency of an electric system depends in great extent of the reactive power compensation that is carried out. One of the ways most used for reactive is power of capacitor banks. A good selection of these, presupposes three aspects: the selection of the banks capacity, the compensator type to be used and the

  2. Reactive Arthritis

    Directory of Open Access Journals (Sweden)

    Eren Erken

    2013-06-01

    Full Text Available Reactive arthritis is an acute, sterile, non-suppurative and inflammatory arthropaty which has occured as a result of an infectious processes, mostly after gastrointestinal and genitourinary tract infections. Reiter syndrome is a frequent type of reactive arthritis. Both reactive arthritis and Reiter syndrome belong to the group of seronegative spondyloarthropathies, associated with HLA-B27 positivity and characterized by ongoing inflammation after an infectious episode. The classical triad of Reiter syndrome is defined as arthritis, conjuctivitis and urethritis and is seen only in one third of patients with Reiter syndrome. Recently, seronegative asymmetric arthritis and typical extraarticular involvement are thought to be adequate for the diagnosis. However, there is no established criteria for the diagnosis of reactive arthritis and the number of randomized and controlled studies about the therapy is not enough. [Archives Medical Review Journal 2013; 22(3.000: 283-299

  3. Prospects for application of high-temperature helium reactor (HTHR) to provide for power needs in refineries and petrochemical plants

    International Nuclear Information System (INIS)

    Feigin, E.A.; Raud, E.A.; Romanova, E.G.; Panasenko, P.A.; Nikitin, V.N.

    1990-01-01

    An analysis performed shows that heat supply from High Temperature Helium Reactor (HTHR) located several miles from crude oil refining units, operating at 360-400 deg. C, can be arranged to use organic heat-carriers. At higher operating temperatures most acceptable are saline carriers. However the final choice of heat carries requires extra research including that on a large scale basis in order to improve the technology and equipment of the heat-supply system. The following problems can be solved by implementing HTHRs at the crude oil processing and petrochemical plants: improving pollution control, making more hydrocarbon fuel available for other uses, intensifying the operation of process units, and making them less fire hazardous, increasing the power efficiency of process plants

  4. Mannuronic Acids : Reactivity and Selectivity

    NARCIS (Netherlands)

    Codee, Jeroen D. C.; Walvoort, Marthe T. C.; de Jong, Ana-Rae; Lodder, Gerrit; Overkleeft, Herman S.; van der Marel, Gijsbert A.

    2011-01-01

    This review describes our recent studies toward the reactivity and selectivity of mannopyranosyl uronic acid donors, which have been found to be very powerful donors for the construction of beta-mannosidic linkages.

  5. A heuristic model for planning problem solution of reactive in electric power systems; Um modelo heuristico para solucao do problema de planejamento de reativos em sistemas de energia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Mantovani, Jose Roberto Sanches

    1995-02-01

    This work introduces a model to solve the planning problem of reactive in electric power systems. The proposed method uses mixed integer linear programming and is solved using implicit enumeration (binary search). The special heuristics to reduce candidates' initial set and to obtain discreet solutions are adopted. They were going accomplished two algorithm implementations, one sequential and other parallel. The implementation parallel uses an asynchronous programming model and is adjusted for distributed memory computer. Defined a bars candidates set for the new reactive sources allocation, the developed program supplies the location and the reactive sources magnitude that must be allocated in the system, considering safety and operation restrictions. The implementation parallel performance is evaluated for three real systems of 309, 725 and 810 bars. The results for the test systems IEEE30 and IEEE118, and the three real systems used in the implementation parallel evaluation are also presented.

  6. A heuristic model for planning problem solution of reactive in electric power systems; Um modelo heuristico para solucao do problema de planejamento de reativos em sistemas de energia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Mantovani, Jose Roberto Sanches

    1995-02-01

    This work introduces a model to solve the planning problem of reactive in electric power systems. The proposed method uses mixed integer linear programming and is solved using implicit enumeration (binary search). The special heuristics to reduce candidates' initial set and to obtain discreet solutions are adopted. They were going accomplished two algorithm implementations, one sequential and other parallel. The implementation parallel uses an asynchronous programming model and is adjusted for distributed memory computer. Defined a bars candidates set for the new reactive sources allocation, the developed program supplies the location and the reactive sources magnitude that must be allocated in the system, considering safety and operation restrictions. The implementation parallel performance is evaluated for three real systems of 309, 725 and 810 bars. The results for the test systems IEEE30 and IEEE118, and the three real systems used in the implementation parallel evaluation are also presented.

  7. FDG-PET status following chemoradiotherapy provides high management impact and powerful prognostic stratification in oesophageal cancer

    International Nuclear Information System (INIS)

    Duong, Cuong P.; Thomas, Robert J.S.; Hicks, Rodney J.; Drummond, Elizabeth; Weih, LeAnn; Leong, Trevor; Michael, Michael

    2006-01-01

    The purpose of this study was to evaluate the impact of FDG-PET following chemoradiotherapy (CRT) on treatment planning and survival in patients with oesophageal cancer (OC). Fifty-three consecutive OC patients had a post-treatment PET scan to evaluate tumour response to CRT prior to possible surgery. Baseline pre-CRT PET was performed in 33 patients. Prospectively recorded post-CRT management plans were compared with post-PET treatment. High impact was defined as a change in treatment intent or modality. Survival was analysed using the Kaplan-Meier product limit method and Cox proportional hazards regression model. After completion of CRT, 23/53 patients (43%) achieved complete metabolic response (CMR), as compared with only four (8%) with complete response on computed tomography. High PET impact was observed in 19 patients (36%). CMR was strongly predictive of survival (p<0.008) on multivariate analysis. CMR patients in whom resection was not performed had comparable survival to those (CMR and non-CMR) who underwent resection. The use of post-treatment FDG-PET for assessment of tumour response after CRT changed the clinical management of more than one-third of OC patients. CMR status as assessed by PET powerfully stratified prognosis. Even in the absence of a baseline study, normalisation of uptake at all sites of known tumoral involvement carries a good medium-term prognosis. (orig.)

  8. Modelación de los efectos de la compensación de potencia reactiva en sistemas de suministro eléctrico Modelation of effects on reactive power compensation in secondary power systems

    Directory of Open Access Journals (Sweden)

    Davel Borges Vasconcellos

    2012-08-01

    Full Text Available Se presentan los inconvenientes de la potencia reactiva y a partir de allí se realiza la modelación matemática de los efectos económicos de ésta, aplicable a sistemas de suministro eléctrico. Los efectos tomados en cuenta son: los costos de inversión de los bancos de capacitores, los gastos de amortización de los bancos, los gastos de pérdidas de energía activa de los bancos, los beneficios por la mejora del factor de potencia, incluida la reducción de pérdidas de energía activa en el sistema, así como los beneficios por la liberación de la capacidad de carga, para el caso de empresas donde este aspecto pueda representar un atractivo económico. Para el análisis de los estados de carga antes y después de la compensación se utilizan algoritmos de flujos de potencia trifásicos, con el empleo de modelos de gráficos de carga ajustados, como aspecto novedoso. Estos efectos, de acuerdo con el sistema de tarifas eléctricas de Cuba, son integrados en una función de análisis económico, en este caso el Valor Actual Neto (VAN, la cual sirve de base para el planteamiento del problema de optimización, que puede derivar en la correcta selección de los dispositivos compensadores.The inconveniences of the reactive power are presented and from this are carried out the mathematical models of its economic effects applicable to secondary power systems. The effects taken into account are: the costs of the capacitors banks, the expenses of paying-off to the banks, the expenses of power losses to the banks, the benefits for the improvement of the power factor, included the reduction of power loss in the system, as well as the benefits for the liberation of the load capacity, to the case of companies where the latest aspect can represent an economic attractiveness. For the analysis after and before compensation, are consider load flow algorithm witch load model adjust. According to electrical tariff structures in Cuba, these effects are

  9. The power of a collaborative relationship between technical assistance providers and community prevention teams: A correlational and longitudinal study.

    Science.gov (United States)

    Chilenski, Sarah M; Perkins, Daniel F; Olson, Jonathan; Hoffman, Lesa; Feinberg, Mark E; Greenberg, Mark; Welsh, Janet; Crowley, D Max; Spoth, Richard

    2016-02-01

    Historically, effectiveness of community collaborative prevention efforts has been mixed. Consequently, research has been undertaken to better understand the factors that support their effectiveness; theory and some related empirical research suggests that the provision of technical assistance is one important supporting factor. The current study examines one aspect of technical assistance that may be important in supporting coalition effectiveness, the collaborative relationship between the technical assistance provider and site lead implementer. Four and one-half years of data were collected from technical assistance providers and prevention team members from the 14 community prevention teams involved in the PROSPER project. Spearman correlation analyses with longitudinal data show that the levels of the collaborative relationship during one phase of collaborative team functioning associated with characteristics of internal team functioning in future phases. Results suggest that community collaborative prevention work should consider the collaborative nature of the technical assistance provider - prevention community team relationship when designing and conducting technical assistance activities, and it may be important to continually assess these dynamics to support high quality implementation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Compositionally modulated multilayer diamond-like carbon coatings with AlTiSi multi-doping by reactive high power impulse magnetron sputtering

    Science.gov (United States)

    Dai, Wei; Gao, Xiang; Liu, Jingmao; Kwon, Se-Hun; Wang, Qimin

    2017-12-01

    Diamond-like carbon (DLC) coatings with AlTiSi multi-doping were prepared by a reactive high power impulse magnetron sputtering with using a gas mixture of Ar and C2H2 as precursor. The composition, microstructure, compressive stress, and mechanical property of the as-deposited DLC coatings were studied systemically by using SEM, XPS, TEM, Raman spectrum, stress-tester, and nanoindentation as a function of the Ar fraction. The results show that the doping concentrations of the Al, Ti and Si atoms increased as the Ar fraction increased. The doped Ti and Si preferred to bond with C while the doped Al mainly existed in oxidation state without bonding with C. As the doping concentrations increased, TiC carbide nanocrystals were formed in the DLC matrix. The microstructure of coatings changed from an amorphous feature dominant AlTiSi-DLC to a carbide nanocomposite AlTiSi-DLC with TiC nanoparticles embedding. In addition, the coatings exhibited the compositionally modulated multilayer consisting of alternate Al-rich layer and Al-poor layer due to the rotation of the substrate holder and the diffusion behavior of the doped Al which tended to separate from C and diffuse towards the DLC matrix surface owing to its weak interactions with C. The periodic Al-rich layer can effectively release the compressive stress of the coatings. On the other hand, the hard TiC nanoparticles were conducive to the hardness of the coatings. Consequently, the DLC coatings with relatively low residual stress and high hardness could be acquired successfully through AlTiSi multi-doping. It is believed that the AlCrSi multi-doping may be a good way for improving the comprehensive properties of the DLC coatings. In addition, we believe that the DLC coatings with Al-rich multilayered structure have a high oxidation resistance, which allows the DLC coatings application in high temperature environment.

  11. Providing all global energy with wind, water, and solar power, Part I: Technologies, energy resources, quantities and areas of infrastructure, and materials

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Mark Z., E-mail: jacobson@stanford.ed [Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305-4020 (United States); Delucchi, Mark A., E-mail: madelucchi@ucdavis.ed [Institute of Transportation Studies, University of California at Davis, Davis, CA 95616 (United States)

    2011-03-15

    Climate change, pollution, and energy insecurity are among the greatest problems of our time. Addressing them requires major changes in our energy infrastructure. Here, we analyze the feasibility of providing worldwide energy for all purposes (electric power, transportation, heating/cooling, etc.) from wind, water, and sunlight (WWS). In Part I, we discuss WWS energy system characteristics, current and future energy demand, availability of WWS resources, numbers of WWS devices, and area and material requirements. In Part II, we address variability, economics, and policy of WWS energy. We estimate that {approx}3,800,000 5 MW wind turbines, {approx}49,000 300 MW concentrated solar plants, {approx}40,000 300 MW solar PV power plants, {approx}1.7 billion 3 kW rooftop PV systems, {approx}5350 100 MW geothermal power plants, {approx}270 new 1300 MW hydroelectric power plants, {approx}720,000 0.75 MW wave devices, and {approx}490,000 1 MW tidal turbines can power a 2030 WWS world that uses electricity and electrolytic hydrogen for all purposes. Such a WWS infrastructure reduces world power demand by 30% and requires only {approx}0.41% and {approx}0.59% more of the world's land for footprint and spacing, respectively. We suggest producing all new energy with WWS by 2030 and replacing the pre-existing energy by 2050. Barriers to the plan are primarily social and political, not technological or economic. The energy cost in a WWS world should be similar to that today. - Research highlights: {yields} Replacing world energy with wind, water, and sun (WWS) reduces world power demand 30%. {yields} WWS for world requires only 0.41% and 0.51% more world land for footprint and spacing, respectively. {yields} Practical to provide 100% new energy with WWS by 2030 and replace existing energy by 2050.

  12. Benefits of Demand-Side Response in Providing Frequency Response Service in the Future GB Power System

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Fei, E-mail: fei.teng09@imperial.ac.uk; Aunedi, Marko; Pudjianto, Danny; Strbac, Goran [Department of Electrical and Electronic Engineering, Imperial College London, London (United Kingdom)

    2015-08-18

    The demand for ancillary service is expected to increase significantly in the future Great Britain (GB) electricity system due to high penetration of wind. In particular, the need for frequency response, required to deal with sudden frequency drops following a loss of generator, will increase because of the limited inertia capability of wind plants. This paper quantifies the requirements for primary frequency response and analyses the benefits of frequency response provision from demand-side response (DSR). The results show dramatic changes in frequency response requirements driven by high penetration of wind. Case studies carried out by using an advanced stochastic generation scheduling model suggest that the provision of frequency response from DSR could greatly reduce the system operation cost, wind curtailment, and carbon emissions in the future GB system characterized by high penetration of wind. Furthermore, the results demonstrate that the benefit of DSR shows significant diurnal and seasonal variation, whereas an even more rapid (instant) delivery of frequency response from DSR could provide significant additional value. Our studies also indicate that the competing technologies to DSR, namely battery storage, and more flexible generation could potentially reduce its value by up to 35%, still leaving significant room to deploy DSR as frequency response provider.

  13. Benefits of Demand-Side Response in Providing Frequency Response Service in the Future GB Power System

    International Nuclear Information System (INIS)

    Teng, Fei; Aunedi, Marko; Pudjianto, Danny; Strbac, Goran

    2015-01-01

    The demand for ancillary service is expected to increase significantly in the future Great Britain (GB) electricity system due to high penetration of wind. In particular, the need for frequency response, required to deal with sudden frequency drops following a loss of generator, will increase because of the limited inertia capability of wind plants. This paper quantifies the requirements for primary frequency response and analyses the benefits of frequency response provision from demand-side response (DSR). The results show dramatic changes in frequency response requirements driven by high penetration of wind. Case studies carried out by using an advanced stochastic generation scheduling model suggest that the provision of frequency response from DSR could greatly reduce the system operation cost, wind curtailment, and carbon emissions in the future GB system characterized by high penetration of wind. Furthermore, the results demonstrate that the benefit of DSR shows significant diurnal and seasonal variation, whereas an even more rapid (instant) delivery of frequency response from DSR could provide significant additional value. Our studies also indicate that the competing technologies to DSR, namely battery storage, and more flexible generation could potentially reduce its value by up to 35%, still leaving significant room to deploy DSR as frequency response provider.

  14. Reactivity monitoring for safety purposes on the UK prototype fast reactor

    International Nuclear Information System (INIS)

    Lord, D.J.; Wilkes, D.J.

    1987-01-01

    The small size and high rating of the liquid metal cooled fast breeder reactor (LMFBR) make the provision of safety related instrumentation for individual subassemblies both difficult and expensive. Global monitoring of the core is thus very attractive. Reactivity monitoring is an important part of such global monitoring. Reactivity monitoring on a short timescale (a few seconds) is used on the UK Prototype Fast Reactor (PFR) as a trip parameter and long-term reactivity monitoring is being developed as a means of providing early warning of slowly developing faults. Results are presented from PFR to demonstrate the capabilities of reactivity monitoring in an operational fast reactor power station. (author)

  15. Novel Control Strategy for Multiple Run-of-the-River Hydro Power Plants to Provide Grid Ancillary Services

    Energy Technology Data Exchange (ETDEWEB)

    Mohanpurkar, Manish; Luo, Yusheng; Hovsapian, Rob; Muljadi, Eduard; Gevorgian, Vahan; Koritarov, Vladimir

    2017-07-12

    Hydropower plant (HPP) generation comprises a considerable portion of bulk electricity generation and is delivered with a low-carbon footprint. In fact, HPP electricity generation provides the largest share from renewable energy resources, which include wind and solar. Increasing penetration levels of wind and solar lead to a lower inertia on the electric grid, which poses stability challenges. In recent years, breakthroughs in energy storage technologies have demonstrated the economic and technical feasibility of extensive deployments of renewable energy resources on electric grids. If integrated with scalable, multi-time-step energy storage so that the total output can be controlled, multiple run-of-the-river (ROR) HPPs can be deployed. Although the size of a single energy storage system is much smaller than that of a typical reservoir, the ratings of storages and multiple ROR HPPs approximately equal the rating of a large, conventional HPP. This paper proposes cohesively managing multiple sets of energy storage systems distributed in different locations. This paper also describes the challenges associated with ROR HPP system architecture and operation.

  16. Digital reactivity meter

    International Nuclear Information System (INIS)

    Copie, M.; Valantic, B.

    1978-01-01

    Digital reactivity meters (DRM) are mostly used as measuring instruments, e.g. for calibration of control rods, and there are only a few cases of their incorporation into the control systems of the reactors. To move in this direction there is more development work needed. First of all, fast algorithms are needed for inverse kinetics equations to relieve the computer for more important tasks of reactor model solving in real time. The next problem, currently under investigation, is the incorporation of the reactor thermal-hydraulic model into the DRM so that it can be used in the power range. Such an extension of DHM allows presentation not only of the instantaneous reactivity of the system, but also the inserted reactivity can be estimated from the temperature reactivity feed-backs. One of the applications of this concept is the anomalous digital reactivity monitor (ADRN) as part of the reactor protection system. As a solution of the first problem, a fast algorithm for solving the inverse kinetics equations has been implemented in the off-line program RODCAL on CDC 1700 computer and tested for its accuracy by performing different control rod calibrations on the reactor TRIGA

  17. Radial distribution of power starting from the reactivity using nodal schemes of second and third order; Distribucion radial de potencia a partir de la reactividad usando esquemas nodales de segundo y tercer orden

    Energy Technology Data Exchange (ETDEWEB)

    Delfin L, A.; Alonso V, G. [ININ, Km. 36.5 Carretera Mexico-Toluca, 52045 Ocoyocac, Estado de Mexico (Mexico); Valle G, E. del [IPN-ESFM, 07738 Mexico D.F. (Mexico)]. e-mail: adl@nuclear.inin.mx

    2003-07-01

    In this work two nodal schemes of finite element are presented, one of second and the other of third order of accurate that allow to determine the radial distribution of power starting from the corresponding reactivities.The schemes here developed were obtained taking as starting point the equation developed by Driscoll et al, the one which is based on the diffusion approach of 1-1/2 energy groups. This equation relates the power fraction of an assemble with their reactivity and with the power fractions and reactivities of the assemblies that its surround it. Driscoll and collaborators they solve in form approximate such equation supposing that the reactivity of each assemble it is but a lineal function of the burnt one of the fuel. The spatial approach carries out it with the classic technique of finite differences centered in mesh. Nevertheless that the algebraic system to which its arrive it can be solved without more considerations introduce some additional suppositions and adjustment parameters that it allows them to predict results comparable to those contributed by three dimensions analysis and this way to reduce the one obtained error when its compare their results with those of a production code like CASMO. Also in the two schemes that here are presented the same approaches of Driscoll were used being obtained errors of the one 10% and of 5% for the second schemes and third order respectively for a test case that it was built starting from data of the Cycle 1 of the Unit 1 of the Laguna Verde Nucleo electric plant. These errors its were obtained when comparing with a computer program based on the matrix response method. It is sought to have this way a quick and efficient tool for the multicycle analysis in the fuel management. However, this model presents problems in the appropriate prediction of the average burnt of the nucleus and of the burnt one by lot. (Author)

  18. Power

    DEFF Research Database (Denmark)

    Elmholdt, Claus Westergård; Fogsgaard, Morten

    2016-01-01

    and creativity suggests that when managers give people the opportunity to gain power and explicate that there is reason to be more creative, people will show a boost in creative behaviour. Moreover, this process works best in unstable power hierarchies, which implies that power is treated as a negotiable....... It is thus a central point that power is not necessarily something that breaks down and represses. On the contrary, an explicit focus on the dynamics of power in relation to creativity can be productive for the organisation. Our main focus is to elaborate the implications of this for practice and theory...

  19. Reactive Systems

    DEFF Research Database (Denmark)

    Aceto, Luca; Ingolfsdottir, Anna; Larsen, Kim Guldstrand

    A reactive system comprises networks of computing components, achieving their goals through interaction among themselves and their environment. Thus even relatively small systems may exhibit unexpectedly complex behaviours. As moreover reactive systems are often used in safety critical systems......, the need for mathematically based formal methodology is increasingly important. There are many books that look at particular methodologies for such systems. This book offers a more balanced introduction for graduate students and describes the various approaches, their strengths and weaknesses, and when...... they are best used. Milner's CCS and its operational semantics are introduced, together with the notions of behavioural equivalences based on bisimulation techniques and with recursive extensions of Hennessy-Milner logic. In the second part of the book, the presented theories are extended to take timing issues...

  20. Reactive Programming in Standard ML

    OpenAIRE

    Pucella, Riccardo

    2004-01-01

    Reactive systems are systems that maintain an ongoing interaction with their environment, activated by receiving input events from the environment and producing output events in response. Modern programming languages designed to program such systems use a paradigm based on the notions of instants and activations. We describe a library for Standard ML that provides basic primitives for programming reactive systems. The library is a low-level system upon which more sophisticated reactive behavi...

  1. Pecuniary evaluation of provided service by local and global based dual-dimensional SDC and PSS2B in the context of deregulated power markets

    International Nuclear Information System (INIS)

    Shayeghi, H.; Hashemi, Y.

    2013-01-01

    Highlights: • Assessing the role and performance of SDC and PSS2B in deregulated power markets. • The profit allocation of WADC as an AS provider is involved in this work. • A dual-dimensional SDC scheme for UPFC is applied to damp the power system swings. • The high share of dual-dimensional SDC shows capability of it in enhancing security. - Abstract: The problem of profit allocation of Unified Power Flow Controller-Supplementary Damping Controller (UPFC-SDC) and accelerating power PSS model (PSS2B) is an important and update issue which has not been properly directed yet. The model of UPFC-SDC that has been used in this paper is a dual-dimensional controller that first dimension of control is resulted from local signals and the second dimension is covered by global signals as additional measuring data from appropriate remote network locations, where swings are well observable. Thus, in this paper the profit allocation of Wide Area Damping Controller (WADC) is also presented as an undefined problem in security subject of deregulated power system. Assuming control action by UPFC-SDC and WADC as an Ancillary Service (AS), the contribution of UPFC-SDC in stability enhancement is evaluated. It is important to appropriately choose a criterion to assess the performance of UPFC-SDC, so that a suitable allocation of profit can be achieved. The sum of deviations of damping ratios and real part of eigenvalues is selected as Oscillation Damping Criterion (ODC). Two scenarios for valuation of small signal stability as an AS provided by UPFC-SDC is considered. The first scenario without retuning of controllers and in the second scenario controllers is retuned due to response of the market situation. A multi-objective optimization approach based on ODC, generation costs and UPFC cost is considered and then Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) is utilized for solving this problem. A two area four machine test power system is considered for investigation

  2. Fuel Temperature Coefficient of Reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Loewe, W.E.

    2001-07-31

    A method for measuring the fuel temperature coefficient of reactivity in a heterogeneous nuclear reactor is presented. The method, which is used during normal operation, requires that calibrated control rods be oscillated in a special way at a high reactor power level. The value of the fuel temperature coefficient of reactivity is found from the measured flux responses to these oscillations. Application of the method in a Savannah River reactor charged with natural uranium is discussed.

  3. 76 FR 31957 - Buckeye Power, Inc.; Notice of Filing

    Science.gov (United States)

    2011-06-02

    ... to supply of Reactive Power and Voltage Control from Generation Sources Services, as provided by... Washington, DC. There is an ``eSubscription'' link on the Web site that enables subscribers to receive e-mail...

  4. The influence of the reactive energy in the electric power sector planning and the need of consolidation of the hourly period for evaluation of the power factor of the loads; A influencia da energia eletrica reativa no planejamento do setor eletrico e a necessidade de consolidacao do periodo horario para avaliacao do fator de potencia das cargas

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Moacyr Trindade de Oliveira

    1993-07-01

    Among expectations of optimization of electric power systems and the national electric rating laws, there is the important factors of consumption and transmission of reactive energy which concerns the objectives of electric sector. Related to it, the DNAEE, ELETROBRAS and the concessionaires have been developing studies in order to optimize the electric system performance, and consequently the investments of concessionaires and consumers, reducing costs imposed to society due to the form of consumption and/or compensation of reactive loads. This work shows the evolution and consolidation of tariff studies and electric performance of the system, indicating the ways which attend the expectations os all segments of the society through a small adaptation of present regulations an rules related to reactive energy, making possible the system growing in supply by the minimum cost. The main objective of this work is to reinforce the real necessity of to remain intact all the new regulation of power factor, that has been consolidated by the DNAEE's document number 085/92 and your revaluation document number 613/93, including the interval of hourly integration for reactive energy at the determinate date and show the damages for the society caused by the postponement of this condition, that has been considerate in the document number 613/93, from April 1994 until April 1996, however keeping in 1994 the introduction of the new power factor reference of 0.92. (author)

  5. The influence of the reactive energy in the electric power sector planning and the need of consolidation of the hourly period for evaluation of the power factor of the loads; A influencia da energia eletrica reativa no planejamento do setor eletrico e a necessidade de consolidacao do periodo horario para avaliacao do fator de potencia das cargas

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Moacyr Trindade de Oliveira

    1993-07-01

    Among expectations of optimization of electric power systems and the national electric rating laws, there is the important factors of consumption and transmission of reactive energy which concerns the objectives of electric sector. Related to it, the DNAEE, ELETROBRAS and the concessionaires have been developing studies in order to optimize the electric system performance, and consequently the investments of concessionaires and consumers, reducing costs imposed to society due to the form of consumption and/or compensation of reactive loads. This work shows the evolution and consolidation of tariff studies and electric performance of the system, indicating the ways which attend the expectations os all segments of the society through a small adaptation of present regulations an rules related to reactive energy, making possible the system growing in supply by the minimum cost. The main objective of this work is to reinforce the real necessity of to remain intact all the new regulation of power factor, that has been consolidated by the DNAEE's document number 085/92 and your revaluation document number 613/93, including the interval of hourly integration for reactive energy at the determinate date and show the damages for the society caused by the postponement of this condition, that has been considerate in the document number 613/93, from April 1994 until April 1996, however keeping in 1994 the introduction of the new power factor reference of 0.92. (author)

  6. Reactivity anomaly surveillance in the Fast Flux Test Facility through cycle 3

    International Nuclear Information System (INIS)

    Knutson, B.J.; Harris, R.A.

    1984-08-01

    The technique for monitoring core reactivity during power operation used at the Fast Flux Test Facility (FFTF) is described. This technique relies on comparing predicted to measured rod positions to detect any anomalous (or unpredicted) core reactivity changes. It is implemented on the Plant Data System (PDS) computer and thus provides rapid indication of any abnormal core conditions. The prediction algorithms use thermal-hydraulic, control rod position and neutron flux sensor information to predict the core reactivity state. Initial results of using this technique based mainly on theoretical formulations is presented. The results show that the reactivity changes due to increasing reactor power (power defect) and burnup of the fuel were within approx. 16% of predicted values. To increase the sensitivity and accuracy of this technique, the prediction algorithms were calibrated to actual operating data. The work of calibrating this technique and the results of using the calibrated technique up through the third full operating cycle are summarized

  7. Power conditioning unit for photovoltaic power systems

    Science.gov (United States)

    Beghin, G.; Nguyen Phuoc, V. T.

    Operational features and components of a power conditioning unit for interconnecting solar cell module powers with a utility grid are outlined. The two-stage unit first modifies the voltage to desired levels on an internal dc link, then inverts the current in 2 power transformers connected to a vector summation control to neutralize harmonic distortion up to the 11th harmonic. The system operates in parallel with the grid with extra inductors to absorb line-to-line voltage and phase differences, and permits peak power use from the PV array. Reactive power is gained internally, and a power system controller monitors voltages, frequencies, and currents. A booster preregulator adjusts the input voltage from the array to provide voltage regulation for the inverter, and can commutate 450 amps. A total harmonic distortion of less than 5 percent is claimed, with a rating of 5 kVA, 50/60 Hz, 3-phase, and 4-wire.

  8. How to provide risk information. Based on citizen's evaluation of messages concerning radiation protection and anti-earthquake measures of nuclear power plant

    International Nuclear Information System (INIS)

    Tsuchiya, Tomoko; Kosugi, Motoko; Nakamura, Yasushi; Takahashi, Shigeaki; Harayama, Satoko

    2009-01-01

    The Framework for Nuclear Energy Policy in Japan, decided in 2005, requests implementation of risk communication to regain social trust on nuclear industry. Electric power companies, however, have few experiences of providing risk information as the first step of risk communication. This report analyzes which message is understandable, useful and trustworthy, by comparing two sets of different messages concerning radiation protection and anti-earthquake measures of nuclear power plant, respectively, based on interview survey for 30 people live in Tokyo metropolitan area. Participants in our survey evaluate the message about radiation protection including risk information is more reliable than one without risk information, but the former is less understandable and more anxious than the latter. In the case of messages regarding seismic measures of nuclear power plant, people are not satisfied with the argument which anti-earthquake measures are implemented, but want to know adequate grounds on which to admit that those measures are thorough. Another message of seismic measures we drafted contains basic knowledge about scales of earthquake, and shows that nuclear industry will consider bigger earthquake than ones in the past records, learn from past experience and improve their measures. 70% of participants assess this message more understandable, useful and trustworthy than the other to explain only seismic measures implemented. (author)

  9. Engine combustion control via fuel reactivity stratification

    Science.gov (United States)

    Reitz, Rolf Deneys; Hanson, Reed M; Splitter, Derek A; Kokjohn, Sage L

    2013-12-31

    A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choose the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

  10. Power imbalance and consumerism in the doctor-patient relationship: health care providers' experiences of patient encounters in a rural district in India.

    Science.gov (United States)

    Fochsen, Grethe; Deshpande, Kirti; Thorson, Anna

    2006-11-01

    The aim of this study is to explore health care providers' experiences and perceptions of their encounters with male and female patients in a rural district in India with special reference to tuberculosis (TB) care. The authors conducted semistructured interviews with 22 health care providers, 17 men and 5 women, from the public and private health care sectors. Findings reveal that doctors adopted an authoritarian as well as a consumerist approach in the medical encounter, indicating that power imbalances in the doctor-patient relationship are negotiable and subject to change. Gender was identified as an influencing factor of the doctor's dominance. A patient-centered approach, acknowledging patients' own experiences and shared decision making, is called for and should be included in TB control activities. This seems to be especially important for female patients, whose voices were not heard in the medical encounter.

  11. Power quality issues current harmonics

    CERN Document Server

    Mikkili, Suresh

    2015-01-01

    Power Quality Issues: Current Harmonics provides solutions for the mitigation of power quality problems related to harmonics. Focusing on active power filters (APFs) due to their excellent harmonic and reactive power compensation in two-wire (single phase), three-wire (three-phase without neutral), and four-wire (three-phase with neutral) AC power networks with nonlinear loads, the text:Introduces the APF technology, describing various APF configurations and offering guidelines for the selection of APFs for specific application considerationsCompares shunt active filter (SHAF) control strategi

  12. Markets in real electric networks require reactive prices

    International Nuclear Information System (INIS)

    Hogan, W.W.

    1996-01-01

    Extending earlier seminal work, the author finds that locational spot price differences in an electric network provide the natural measure of the appropriate internodal transport charge. However, the problem of loop flow requires different economic intuition for interpreting the implications of spot pricing. The Direct Current model, which is the usual approximation for estimating spot prices, ignores reactive power effects; this approximation is best when thermal constraints create network congestion. However, when voltage constraints are problematic, the DC Load model is insufficient; a full AC Model is required to determine both real and reactive spot prices. 16 figs., 3 tabs., 22 refs

  13. Reactivity margins in heavy water moderated production reactors

    International Nuclear Information System (INIS)

    Benton, F.D.

    1981-11-01

    The design of the reactor core and components of the heavy water moderated reactors at the Savannah River Plant (SFP) can be varied to produce a number of isotopes. For the past decade, the predominant reactor core design has been the enriched-depleted lattice. In this lattice, fuel assemblies of highly enriched uranium and target assemblies of depleted uranium, which produce plutonium, occupy alternate lattice positions. This heterogeneous lattice arrangement and a nonuniform control rod distribution result in a reactor core that requires sophisticated calculational methods for accurate reactivity margin and power distribution predictions. For maximum accuracy, techniques must exist to provide a base of observed data for the calculations. Frequent enriched-depleted lattice design changes are required as product demands vary. These changes provided incentive for the development of techniques to combine the results of calculations and observed reactivity data to accurately and conveniently monitor reactivity margins during operation

  14. Effect of input power and gas pressure on the roughening and selective etching of SiO2/Si surfaces in reactive plasmas

    International Nuclear Information System (INIS)

    Zhong, X. X.; Huang, X. Z.; Tam, E.; Ostrikov, K.; Colpo, P.; Rossi, F.

    2010-01-01

    We report on the application low-temperature plasmas for roughening Si surfaces which is becoming increasingly important for a number of applications ranging from Si quantum dots to cell and protein attachment for devices such as 'laboratory on a chip' and sensors. It is a requirement that Si surface roughening is scalable and is a single-step process. It is shown that the removal of naturally forming SiO 2 can be used to assist in the roughening of the surface using a low-temperature plasma-based etching approach, similar to the commonly used in semiconductor micromanufacturing. It is demonstrated that the selectivity of SiO 2 /Si etching can be easily controlled by tuning the plasma power, working gas pressure, and other discharge parameters. The achieved selectivity ranges from 0.4 to 25.2 thus providing an effective means for the control of surface roughness of Si during the oxide layer removal, which is required for many advance applications in bio- and nanotechnology.

  15. Ultra Efficient CHHP Using a High Temperature Fuel Cell to Provide On-Site Process Reducing Gas, Clean Power, and Heat

    Energy Technology Data Exchange (ETDEWEB)

    Jahnke, Fred C. [Fuelcell Energy, Inc., Danbury, CT (United States)

    2015-06-30

    FuelCell Energy and ACuPowder investigated and demonstrated the use of waste anode exhaust gas from a high temperature fuel cell for replacing the reducing gas in a metal processing furnace. Currently companies purchase high pressure or liquefied gases for the reducing gas which requires substantial energy in production, compression/liquefaction, and transportation, all of which is eliminated by on-site use of anode exhaust gas as reducing gas. We performed research on the impact of the gas composition on product quality and then demonstrated at FuelCell Energy’s manufacturing facility in Torrington, Connecticut. This demonstration project continues to operate even though the research program is completed as it provides substantial benefits to the manufacturing facility by supplying power, heat, and hydrogen.

  16. Power quality improvements of wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Soebrink, Kent H. [Eltra (Denmark); Stoeber, Ralf; Schettler, Frank; Bergmann, Klaus [Siemens (Germany); Jenkins, Nicholas; Ekanayake, Janaka; Saad-Saoud, Zouhir; Liboa, Maria Luiza; Strbac, Goran [UMIST (United Kingdom); Kaas Pedersen, Joergen; Helgesen Pedersen, Knud Ole [Technical Univ. of Denmark (Denmark)

    1998-06-01

    The main objective of the project was to investigate how the power quality of the electrical output of wind farms could be improved by the use of modern high power electronic technology. Although the research is of direct application to wind energy it will also be relevant to many other types of small-scale generation embedded in utility distribution networks. The operation of wind turbines with asynchronous generators requires reactive power which, if supplied form the network, leads to low voltages and increased losses. In order to improve the power factor of the generation, fixed capacitors are usually used to provide reactive power. However, if they are sized for the full requirement of the wind farm, they can cause self-excitation and potentially damaging and hazardous overvoltages if the wind turbines` connection with the network is interrupted and they become islanded. An advanced Static VAr Compensator (ASVC) uses a power electronic converter to generate or absorb reactive power. They can be used to provide reactive power with rapid control and with only modestly sized passive components (i.e. small capacitors and reactors). The objective of the project was to combine research and development of this novel form of electronic equipment with its application to increase the use of renewable energy, and wind power in particular, in the European Union. (EG) 19 refs.

  17. Contribution to the qualification of calculation methods of reactivity and of flux and power distributions in nuclear pressurized water reactor cores

    International Nuclear Information System (INIS)

    Abit, K.

    1984-01-01

    The last stage of the creation computer methods and calculations consists of verifying the running and qualifying the results obtained. The work of the present thesis consisted of improving a coupling method between radial and axial phenomena in a PWR core, refering to three-dimensional calculations, while ensuring a perfect coherence between the programmed physical models. The calculation results have been compared to measurements of reactivity and of flux distributions realized during start-up tests. Thus, the methods have been applied to the calculation of the evolution of a burnable poison (gadolinium) in view of operation in long campaign. 13 refs [fr

  18. Measurement and modeling of plasma parameters in reactive high-power impulse magnetron sputtering of Ti in Ar/O.sub.2./sub. mixtures

    Czech Academy of Sciences Publication Activity Database

    Čada, Martin; Lundin, D.; Hubička, Zdeněk

    2017-01-01

    Roč. 121, č. 17 (2017), s. 1-7, č. článku 171913. ISSN 0021-8979 R&D Projects: GA ČR(CZ) GA15-00863S EU Projects: European Commission(XE) 608800 - HIPPOCAMP Institutional support: RVO:68378271 Keywords : reactive sputtering * HiPIMS * Langmuir probe * R-IRM model * plasma density * electron temperature Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.068, year: 2016

  19. The influence of the reactivity ramp on the course of the power transient in the MARK 1A core of the SNR 300

    International Nuclear Information System (INIS)

    Froehlich, R.; Schmuck, P.

    1976-01-01

    The course of a hypothetic transient overpower accident caused by the onset of a not further specified reactivity ramp accompanied by the simultaneous failure of both shutdown systems must be analyzed in the SNR 300 Mark 1A core licensing procedure. The present study is limited to the discussion of the starting and shutdown phases of such accidents for the fresh core. Depending on the operational state of the reactor, the core geometry is still intact during the starting phase. In the following shutdown phase (core disassembly phase), large-scale mass transfer leads to the nuclear shutdown of the reactor. (orig./AK) [de

  20. Spring 5 & reactive streams

    CERN Multimedia

    CERN. Geneva; Clozel, Brian

    2017-01-01

    Spring is a framework widely used by the world-wide Java community, and it is also extensively used at CERN. The accelerator control system is constituted of 10 million lines of Java code, spread across more than 1000 projects (jars) developed by 160 software engineers. Around half of this (all server-side Java code) is based on the Spring framework. Warning: the speakers will assume that people attending the seminar are familiar with Java and Spring’s basic concepts. Spring 5.0 and Spring Boot 2.0 updates (45 min) This talk will cover the big ticket items in the 5.0 release of Spring (including Kotlin support, @Nullable and JDK9) and provide an update on Spring Boot 2.0, which is scheduled for the end of the year. Reactive Spring (1h) Spring Framework 5.0 has been released - and it now supports reactive applications in the Spring ecosystem. During this presentation, we'll talk about the reactive foundations of Spring Framework with the Reactor project and the reactive streams specification. We'll al...

  1. Pragmatic power

    CERN Document Server

    Eccles, William

    2008-01-01

    Pragmatic Power is focused on just three aspects of the AC electrical power system that supplies and moves the vast majority of electrical energy nearly everywhere in the world: three-phase power systems, transformers, and induction motors. The reader needs to have had an introduction to electrical circuits and AC power, although the text begins with a review of the basics of AC power. Balanced three-phase systems are studied by developing their single-phase equivalents. The study includes a look at how the cost of ""power"" is affected by reactive power and power factor. Transformers are cons

  2. Reflections of Homeless Women and Women with Mental Health Challenges on Breast and Cervical Cancer Screening Decisions: Power, Trust, and Communication with Care Providers

    Directory of Open Access Journals (Sweden)

    Catherine Claire Moravac

    2018-02-01

    Full Text Available This study conducted in Toronto, Canada, explored the perceptions of women living in homeless shelters and women with severe mental health challenges about the factors influencing their decision-making processes regarding breast and cervical cancer screening. Twenty-six in-depth qualitative interviews were conducted. The objectives of this research were (i to provide new insights about women’s decision-making processes, (ii to describe the barriers to and facilitators for breast and cervical cancer screening, and (iii to offer recommendations for future outreach, education, and screening initiatives developed specifically for under/never-screened marginalized women living in urban centers. This exploratory study utilized thematic analysis to broaden our understanding about women’s decision-making processes. A constructed ontology1 was used in an attempt to understand and describe participants’ constructed realities. The epistemological framework was subjective and reflected co-created knowledge. The approach was hegemonic, values-based, and context-specific. The aim of the analysis was to focus on meanings and actions with a broader view to identify the interplay between participants’ narratives and social structures, medical praxis, and policy implications. Results from 26 qualitative interviews conducted in 2013–2014 provided insights on both positive and negative prior cancer screening experiences, the role of power and trust in women’s decision-making, and areas for improvement in health care provider/patient interactions. Outcomes of this investigation contribute to the future development of appropriately designed intervention programs for marginalized women, as well as for sensitivity training for health care providers. Tailored and effective health promotion strategies leading to life-long cancer screening behaviors among marginalized women may improve clinical outcomes, decrease treatment costs, and save lives.

  3. Low voltage ride-through capability control for single-stage inverter-based grid-connected photovoltaic power plant

    DEFF Research Database (Denmark)

    Al-Shetwi, Ali Q.; Sujod, Muhamad Zahim; Blaabjerg, Frede

    2018-01-01

    and current limiter are used to absorb the excessive dc-voltage and limits excessive ac current, respectively. This control strategy can also ensure the reactive power support through the injection of reactive current according to the standard requirements as soon as the voltage sag is detected. Furthermore...... to improve the capability of ride-through fault safely and keep the inverter connected, but also to provide grid support through active and reactive power control at different type of faults....

  4. Influence of the electrical power applied to the target on the optical and structural properties of ZrON films produced via RF magnetron sputtering in a reactive atmosphere

    International Nuclear Information System (INIS)

    Pinzón, M.J.; Alfonso, J.E.; Olaya, J.J.; Cubillos, G.I.; Romero, E.

    2014-01-01

    The influence of the variation of electrical power applied to the target on the morphology and optical properties of zirconium oxynitride - zirconium oxide (ZrON) films deposited via RF magnetron sputtering on common glass substrates in a reactive atmosphere of N 2 /O 2 , with a flow ratio ΦN 2 /ΦO 2 of 1.25 was investigated. The crystallographic structure of the films was established through X-ray diffraction (XRD), the morphology was evaluated through scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the optical behavior was evaluated through transmittance measurements. The XRD analysis showed that the films grew with mixed crystalline structures: monoclinic (ZrO 2 ) and body-centered cubic (Zr 2 ON 2 ). SEM analysis showed that the films grew with a homogeneous morphology, and AFM results established that as the electrical power applied to the target increased, there were changes in the grain size and the roughness of the films. The thickness, refractive index, and absorption coefficient of the films were calculated using the values of the transmittance through the Swanepoel method. Additionally, the energy band gap was determined via analysis of the free interference region. - Highlights: • We growth zirconium oxynitride films by RF magnetron sputtering in reactive atmosphere. • We determine the influence of the electrical power applied at the target in optical and structural properties. • We determine the crystallite size, grain size and roughness of the zirconium oxynitride films. • We determine the optical parameters such refractive index of the zirconium oxynitride films through Swanepoel method. • We calculated the absorption coefficient and optical band gap of the zirconium oxynitride films

  5. Influence of the electrical power applied to the target on the optical and structural properties of ZrON films produced via RF magnetron sputtering in a reactive atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Pinzón, M.J. [Grupo de Ciencia de Materiales y Superficies, Departamento de Física, Universidad Nacional de Colombia, AA 14490 Bogotá (Colombia); Alfonso, J.E., E-mail: jealfonsoo@unal.edu.co [Grupo de Ciencia de Materiales y Superficies, Departamento de Física, Universidad Nacional de Colombia, AA 14490 Bogotá (Colombia); Olaya, J.J. [Grupo de Ciencia de Materiales y Superficies, Departamento de Física, Universidad Nacional de Colombia, AA 14490 Bogotá (Colombia); Cubillos, G.I.; Romero, E. [Grupo de Materiales y Procesos Químicos, Universidad Nacional de Colombia, AA 14490 Bogotá (Colombia)

    2014-12-01

    The influence of the variation of electrical power applied to the target on the morphology and optical properties of zirconium oxynitride - zirconium oxide (ZrON) films deposited via RF magnetron sputtering on common glass substrates in a reactive atmosphere of N{sub 2}/O{sub 2}, with a flow ratio ΦN{sub 2}/ΦO{sub 2} of 1.25 was investigated. The crystallographic structure of the films was established through X-ray diffraction (XRD), the morphology was evaluated through scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the optical behavior was evaluated through transmittance measurements. The XRD analysis showed that the films grew with mixed crystalline structures: monoclinic (ZrO{sub 2}) and body-centered cubic (Zr{sub 2}ON{sub 2}). SEM analysis showed that the films grew with a homogeneous morphology, and AFM results established that as the electrical power applied to the target increased, there were changes in the grain size and the roughness of the films. The thickness, refractive index, and absorption coefficient of the films were calculated using the values of the transmittance through the Swanepoel method. Additionally, the energy band gap was determined via analysis of the free interference region. - Highlights: • We growth zirconium oxynitride films by RF magnetron sputtering in reactive atmosphere. • We determine the influence of the electrical power applied at the target in optical and structural properties. • We determine the crystallite size, grain size and roughness of the zirconium oxynitride films. • We determine the optical parameters such refractive index of the zirconium oxynitride films through Swanepoel method. • We calculated the absorption coefficient and optical band gap of the zirconium oxynitride films.

  6. The reactivity meter and core reactivity

    International Nuclear Information System (INIS)

    Siltanen, P.

    1999-01-01

    This paper discussed in depth the point kinetic equations and the characteristics of the point kinetic reactivity meter, particularly for large negative reactivities. From a given input signal representing the neutron flux seen by a detector, the meter computes a value of reactivity in dollars (ρ/β), based on inverse point kinetics. The prompt jump point of view is emphasised. (Author)

  7. Peak Provoked Craving: An Alternative to Smoking Cue-Reactivity

    OpenAIRE

    Sayette, Michael A.; Tiffany, Stephen T.

    2012-01-01

    Smoking cue-exposure research has provided a powerful tool for examining cravings in the laboratory. A key attraction of this method is that tightly controlled experimental procedures can model craving experiences that are presumed to relate to addiction. Despite its appeal, key assumptions underlying the clinical relevance of smoking cue reactivity studies recently have been questioned. For both conceptual and methodological reasons it may be quite difficult to tease apart cue-based and abst...

  8. Method of decreasing nuclear power

    International Nuclear Information System (INIS)

    Masuda, Hiromi

    1987-01-01

    Purpose: To easily attain the power decreasing in a HWLWR type reactor and improve the reactor safety. Method: The method is applied to a nuclear reactor in which the reactor reactivity is controlled by control rods and liquid posions dissolved in moderators. Means for forecasting the control rod operation amount required for the reactor power down and means for removing liquid poisons in the moderators are provided. The control rod operation amount required for the power down is forecast before the power down and the liquid poisons in the moderators are removed. Then, the control rods are inserted into a deep insertion position to reduce the reactor power. This invention can facilitate easy power down, as well as provide effects of improving the controllability in the usual operation and of avoiding abrupt power down which leads to an improved availability. (Kamimura, M.)

  9. A fuzzy-based approach for strategic choices in electric energy supply. The case of a Swiss power provider on the eve of electricity market opening

    International Nuclear Information System (INIS)

    Nguene, Gustave Nguene; Finger, Matthias

    2007-01-01

    Risk evaluation and strategic choice has become very complex for power providers, because of the growing number of uncertain parameters involved, such as energy market prices, water inflow, and demand. The lack of information and the absence of the decision maker's perception are just some of the many elements that must be accounted for. Therefore, with an approach based on fuzzy set theory, this paper aims to propose a methodology based on strategic choices that will enable decision makers to evaluate the performance of their strategies and portfolios through the computation of an indicator of economic performance, for different time-horizons. By subsequently considering the different imprecise parameters - such as the electricity spot price, the natural gas market price, rainfall and snow, etc. - in the assessment of different strategies and the analysis of their impacts through scenario analysis, it is concluded that the resulting profit depends not only on the perception of the market player, but also on the imprecision of the variables - the same strategy may produce two different results under a different combination of parameters - as well as on the time-horizon considered. On a simple basis, it has also been possible to compare portfolios of customers. (Author)

  10. A fuzzy-based approach for strategic choices in electric energy supply. The case of a Swiss power provider on the eve of electricity market opening

    Energy Technology Data Exchange (ETDEWEB)

    Nguene, Gustave Nguene; Finger, Matthias [Chair Management of Network Industries (MIR), CdM2013 ILEMT, Odyssea, Station 5, EPFL Ecole Polytechnique Federale de Lausanne, CH2013 1015 Lausanne, (Switzerland)

    2007-02-15

    Risk evaluation and strategic choice has become very complex for power providers, because of the growing number of uncertain parameters involved, such as energy market prices, water inflow, and demand. The lack of information and the absence of the decision maker's perception are just some of the many elements that must be accounted for. Therefore, with an approach based on fuzzy set theory, this paper aims to propose a methodology based on strategic choices that will enable decision makers to evaluate the performance of their strategies and portfolios through the computation of an indicator of economic performance, for different time-horizons. By subsequently considering the different imprecise parameters - such as the electricity spot price, the natural gas market price, rainfall and snow, etc. - in the assessment of different strategies and the analysis of their impacts through scenario analysis, it is concluded that the resulting profit depends not only on the perception of the market player, but also on the imprecision of the variables - the same strategy may produce two different results under a different combination of parameters - as well as on the time-horizon considered. On a simple basis, it has also been possible to compare portfolios of customers. (Author)

  11. Thermodynamic effects when utilizing waste heat from condensation in cases of a reduced vacuum in steam turbine plants of thermal power stations, to provide heat at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Vasiljevic, N.; Savic, B.; Stojakovic, M.

    1986-01-01

    There is an interesting variant of cogeneration in the steam turbine system of a thermal power plant, i.e. the utilisation of the waste heat of condensation with a reduced vacuum without reconstruction of the thermal power plant. The thermodynamic effect in cogeneration was calculated in consideration of the dynamics of heat consumption. This cogeneration process has the advantage of saving primary energy without reconstruction of the thermal power plant.

  12. Spatial weighting of Doppler reactivity feedback

    International Nuclear Information System (INIS)

    Carew, J.F.; Diamond, D.J.; Todosow, M.

    1977-12-01

    The spatial weighting of the local Doppler feedback implicit in the determination of the core Doppler feedback reactivity has been investigated. Using a detailed planar PDQ7-II PWR model with local fuel-temperature feedback, the core Doppler spatial weight factor, S, has been determined for various control patterns and power levels. Assuming power-squared weighting of the local Doppler feedback, a simple analytic expression for S has been derived and, based on comparison with the PDQ7-II results, provides a convenient and accurate representation of the Doppler spatial weight factor. The sensitivity of these results to variations in the fuel rod heat transfer coefficients, fuel loading and the magnitude of the Doppler coefficient has also been evaluated. The dependence of the local Doppler coefficient on moderator temperature, boron concentration and control rod density has been determined and found to be weak. Selected comparisons with vendor analyses have been made and indicate general agreement

  13. Insertion material for controlling reactivity

    International Nuclear Information System (INIS)

    Baba, Iwao.

    1994-01-01

    Moderators and a group of suspended materials having substantially the same density as the moderator are sealed in a hollow rod vertically inserted to a fuel assembly. Specifically, the group of suspended materials is adapted to have a density changing stepwise from density of the moderator at the exit temperature of the reactor core to that at the inlet temperature of the reactor core. Reactivity is selectively controlled for a portion of high power and a portion of high reactivity by utilizing the density of the moderator and the distribution of the density. That is, if the power distribution is flat, the density of the moderators changes at a constant rate over the vertical direction of the reactor core and the suspended materials stay at a portion of the same density, to form a uniform distribution. Further, upon reactor shutdown, since the liquid temperature of the moderators is lowered and the density is increased, all of beads are collected at the upper portion to remove water at the upper portion of the reactor core of low burnup degree thereby selectively controlling the reactivity at a portion of high power and a portion of high reactivity. (N.H.)

  14. A Note on the Power Provided by Sibships of Sizes 2, 3, and 4 in Genetic Covariance Modeling of a Codominant QTL.

    NARCIS (Netherlands)

    Dolan, C.V.; Boomsma, D.I.; Neale, M.C.

    1999-01-01

    The contribution of size 3 and size 4 sibships to power in covariance structure modeling of a codominant QTL is investigated. Power calculations are based on the noncentral chi-square distribution. Sixteen sets of parameter values are considered. Results indicate that size 3 and size 4 sibships

  15. Supercapacitor to Provide Ancillary Services: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, Eduard [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gevorgian, Vahan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Luo, Yusheng [Idaho National Laboratory; Mohanpurkar, M. [Idaho National Laboratory; Hovsapian, R. [Idaho National Laboratory; Koritarov, V. [Argonne National Laboratory

    2017-10-09

    Supercapacitor technology has reached a level of maturity as a viable energy storage option available to support a modern electric power system grid; however, its application is still limited because of its energy capacity and the cost of the commercial product. In this paper, we demonstrate transient models of supercapacitor energy storage plants operating in coordination with run-of-the-river (ROR), doubly-fed induction generator hydropower plants (HPP) using a system control concept and architecture developed. A detailed transient model of a supercapacitor energy storage device is coupled with the grid via a three-phase inverter/rectifier and bidirectional DC-DC converter. In addition, we use a version of a 14-bus IEEE test case that includes the models of the supercapacitor energy storage device, ROR HPPs, and synchronous condensers that use the rotating synchronous generators of retired coal-powered plants. The purpose of the synchronous condensers is to enhance the system stability by providing voltage and reactive power control, provide power system oscillations damping, and maintain system inertia at secure levels. The control layer provides coordinated, decentralized operation of distributed ROR HPPs and energy storage as aggregate support to power system operations.

  16. Reactive dual magnetron sputtering for large area application

    International Nuclear Information System (INIS)

    Struempfel, J.

    2002-01-01

    Production lines for large area coating demand high productivity of reactive magnetron sputtering processes. Increased dynamic deposition rates for oxides and nitrides were already obtained by using of highly powered magnetrons in combination with advanced sputter techniques. However, besides high deposition rates the uniformity of such coatings has to be carefully considered. First the basics of reactive sputtering processes and dual magnetron sputtering are summarized. Different methods for process stabilization and control are commonly used for reactive sputtering. The Plasma Emission Monitor (PE M) offers the prerequisite for fast acting process control derived from the in-situ intensity measurements of a spectral line of the sputtered target material. Combined by multiple Plasma Emission Monitor control loops segmented gas manifolds are able to provide excellent thin film uniformity at high deposition rates. The Dual Magnetron allows a broad range of processing by different power supply modes. Medium frequency, DC and pulsed DC power supplies can be used for high quality layers. Whereas the large area coating of highly isolating layers like TiO 2 or SiO 2 is dominated by MF sputtering best results for coating with transparent conductive oxides are obtained by dual DC powering of the dual magnetron arrangement. (Author)

  17. A simple reactivity-meter system

    International Nuclear Information System (INIS)

    Ferreira, P.S.B.

    1992-01-01

    This paper describes a new version of a reactivity meter developed at the Institute of Nuclear Energy Research (IPEN) (Brazil). The reactivity meter computes the reactor reactivity utilizing a programmable electrometer that performs the data aquisition. The software commands the main functions of the electrometer, the data acquisition, data transfer, and reactivity calculation. The necessary hardware for this reactivity meter are a programmable electrometer, a microcomputer, and interfaces for the microcomputer to communicate with the electrometer. If it is necessary, it is possible to connect a graphic register to the microcomputer. With this conventional hardware, available in any nuclear reactor facility, one can build a powerful reactivity meter. Adding to these advantages, one can use the microcomputer on-line to analyze the data, store the data on diskettes, or create graphics

  18. Reactivity Coefficient Calculation for AP1000 Reactor Using the NODAL3 Code

    Science.gov (United States)

    Pinem, Surian; Malem Sembiring, Tagor; Tukiran; Deswandri; Sunaryo, Geni Rina

    2018-02-01

    The reactivity coefficient is a very important parameter for inherent safety and stability of nuclear reactors operation. To provide the safety analysis of the reactor, the calculation of changes in reactivity caused by temperature is necessary because it is related to the reactor operation. In this paper, the temperature reactivity coefficients of fuel and moderator of the AP1000 core are calculated, as well as the moderator density and boron concentration. All of these coefficients are calculated at the hot full power condition (HFP). All neutron diffusion constant as a function of temperature, water density and boron concentration were generated by the SRAC2006 code. The core calculations for determination of the reactivity coefficient parameter are done by using NODAL3 code. The calculation results show that the fuel temperature, moderator temperature and boron reactivity coefficients are in the range between -2.613 pcm/°C to -4.657pcm/°C, -1.00518 pcm/°C to 1.00649 pcm/°C and -9.11361 pcm/ppm to -8.0751 pcm/ppm, respectively. For the water density reactivity coefficients, the positive reactivity occurs at the water temperature less than 190 °C. The calculation results show that the reactivity coefficients are accurate because the results have a very good agreement with the design value.

  19. AIREKMOD-RR, Reactivity Transients in Nuclear Research Reactors

    International Nuclear Information System (INIS)

    Baggoura, B.; Mazrou, H.

    2001-01-01

    1 - Description of program or function: AIREMOD-RR is a point kinetics code which can simulate fast transients in nuclear research reactor cores. It can also be used for theoretical reactor dynamics studies. It is used for research reactor kinetic analysis and provides a point neutron kinetic capability. The thermal hydraulic behavior is governed by a one-dimensional heat balance equation. The calculations are restricted to a single equivalent unit cell which consists of fuel, clad and coolant. 2 - Method of solution: For transient reactor kinetic calculations a modified Runge Kutta numerical method is used. The external reactivity insertion, specified as a function of time, is converted in dollar ($) unit. The neutron density, energy release and feedback variables are given at each time step. The two types of reactivity feedback considered are: Doppler effect and moderator effect. A new expression for the reactivity dependence on the feedback variables has been introduced in the present version of the code. The feedback reactivities are fitted in power series expression. 3 - Restrictions on the complexity of the problem: The number of delayed neutron groups and the total number of equations are limited only by computer storage capabilities. - Coolant is always in liquid phase. - Void reactivity feedback is not considered

  20. Obtaining additional energy savings from the Filumex project by means of the reactive power compensation; Obtencion de ahorros adicionales del proyecto Filumex mediante la compensacion de la potencia reactiva

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes Jaramillo, Enrique L.; Loredo Gutierrez, Miguel Angel; Hernandez Hernandez, Eduardo [Comision Federal de Electricidad, Mexico, D. F. (Mexico)

    1996-12-31

    This paper presents the proposal for establishing in a parallel way to Flamex project, the compensation in the intermediate tension network for the increment in reactive power supplied to the domestic user. This is due to the following three phenomena that occur in replacing incandescent light bulbs with fluorescent lamps: a) A fluorescent lamp has a power factor of 0.9; consequently it requires the supply of a reactive power of about 50% of its capacity. b) In replacing an incandescent light bulb for a fluorescent lamp, approximately 80% of its capacity is not supplied, this leads to the disappearance of a good deal of the user`s purely resistive load, that will cause that its natural power factor is decreased from 0.91 to 0.86 lagging. c) In decreasing the annual maximum demand in the distribution circuit in a greater proportion than the decrease of the annual consumption, their load factors and the annual losses will be increased and therefore the share of its annual energy losses will be increased in about 18.9%. The above, gives rise to the fact that the compensation of reactive power by means of the installation of capacitor banks in the main leads of the distribution circuit, turns out to be a highly appealing technical-economical solution, with a Benefit/Cost rate of 4, a return time of the investment of 2 years and a net benefit of $4.78/user (Pesos). [Espanol] Se presenta la propuesta para establecer en una forma paralela al proyecto FILUMEX, la compensacion en la red de media tension del incremento de la potencia reactiva suministrada al usuario domestico. Este es debido a los siguientes tres fenomenos que ocurren al sustituir los focos incandescentes por lamparas fluorescentes: a) Una lampara fluorescente tiene un factor de potencia de 0.9, por lo que requiere el suministro de una potencia reactiva de aproximadamente el 50% de su capacidad. b) Al sustituirse un foco incandescente por una lampara fluorescente, se deja de suministrar aproximadamente el 80

  1. Obtaining additional energy savings from the Filumex project by means of the reactive power compensation; Obtencion de ahorros adicionales del proyecto Filumex mediante la compensacion de la potencia reactiva

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes Jaramillo, Enrique L; Loredo Gutierrez, Miguel Angel; Hernandez Hernandez, Eduardo [Comision Federal de Electricidad, Mexico, D. F. (Mexico)

    1997-12-31

    This paper presents the proposal for establishing in a parallel way to Flamex project, the compensation in the intermediate tension network for the increment in reactive power supplied to the domestic user. This is due to the following three phenomena that occur in replacing incandescent light bulbs with fluorescent lamps: a) A fluorescent lamp has a power factor of 0.9; consequently it requires the supply of a reactive power of about 50% of its capacity. b) In replacing an incandescent light bulb for a fluorescent lamp, approximately 80% of its capacity is not supplied, this leads to the disappearance of a good deal of the user`s purely resistive load, that will cause that its natural power factor is decreased from 0.91 to 0.86 lagging. c) In decreasing the annual maximum demand in the distribution circuit in a greater proportion than the decrease of the annual consumption, their load factors and the annual losses will be increased and therefore the share of its annual energy losses will be increased in about 18.9%. The above, gives rise to the fact that the compensation of reactive power by means of the installation of capacitor banks in the main leads of the distribution circuit, turns out to be a highly appealing technical-economical solution, with a Benefit/Cost rate of 4, a return time of the investment of 2 years and a net benefit of $4.78/user (Pesos). [Espanol] Se presenta la propuesta para establecer en una forma paralela al proyecto FILUMEX, la compensacion en la red de media tension del incremento de la potencia reactiva suministrada al usuario domestico. Este es debido a los siguientes tres fenomenos que ocurren al sustituir los focos incandescentes por lamparas fluorescentes: a) Una lampara fluorescente tiene un factor de potencia de 0.9, por lo que requiere el suministro de una potencia reactiva de aproximadamente el 50% de su capacidad. b) Al sustituirse un foco incandescente por una lampara fluorescente, se deja de suministrar aproximadamente el 80

  2. Transmission Lines or Poles, Electric, Electric transmission lines locations provided to us from Kansas City Power and Light and City of Gardner only at this time. AIMS is working on getting other providers in area. Data is limited to CUE (Collaborative Utility Exchange) Participants and subc, Published in 2004, Johnson County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Transmission Lines or Poles, Electric dataset current as of 2004. Electric transmission lines locations provided to us from Kansas City Power and Light and City of...

  3. Electric Substations, Electric substation locations provided to us from Kansas City Power and Light and City of Gardner only at this time. AIMS is working on getting other providers in area. Data is limited to CUE (Collaborative Utility Exchange) Participants and subcontracto, Published in 2004, Johnson County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Electric Substations dataset current as of 2004. Electric substation locations provided to us from Kansas City Power and Light and City of Gardner only at this time....

  4. Establishment of HSV1 latency in immunodeficient mice facilitates efficient in vivo reactivation.

    Directory of Open Access Journals (Sweden)

    Chandran Ramakrishna

    2015-03-01

    Full Text Available The establishment of latent infections in sensory neurons is a remarkably effective immune evasion strategy that accounts for the widespread dissemination of life long Herpes Simplex Virus type 1 (HSV1 infections in humans. Periodic reactivation of latent virus results in asymptomatic shedding and transmission of HSV1 or recurrent disease that is usually mild but can be severe. An in-depth understanding of the mechanisms regulating the maintenance of latency and reactivation are essential for developing new approaches to block reactivation. However, the lack of a reliable mouse model that supports efficient in vivo reactivation (IVR resulting in production of infectious HSV1 and/or disease has hampered progress. Since HSV1 reactivation is enhanced in immunosuppressed hosts, we exploited the antiviral and immunomodulatory activities of IVIG (intravenous immunoglobulins to promote survival of latently infected immunodeficient Rag mice. Latently infected Rag mice derived by high dose (HD, but not low dose (LD, HSV1 inoculation exhibited spontaneous reactivation. Following hyperthermia stress (HS, the majority of HD inoculated mice developed HSV1 encephalitis (HSE rapidly and synchronously, whereas for LD inoculated mice reactivated HSV1 persisted only transiently in trigeminal ganglia (Tg. T cells, but not B cells, were required to suppress spontaneous reactivation in HD inoculated latently infected mice. Transfer of HSV1 memory but not OVA specific or naïve T cells prior to HS blocked IVR, revealing the utility of this powerful Rag latency model for studying immune mechanisms involved in control of reactivation. Crossing Rag mice to various knockout strains and infecting them with wild type or mutant HSV1 strains is expected to provide novel insights into the role of specific cellular and viral genes in reactivation, thereby facilitating identification of new targets with the potential to block reactivation.

  5. Evaluation of reactivity and Xe behavior during daily load following operation

    International Nuclear Information System (INIS)

    Sakamoto, Yasunori; Araki, Tsuneyasu; Yamamoto, Fumiaki

    1992-01-01

    A boiling water reactor (BWR) has an excellent load following capability provided by a core flow control, which is used for changing a reactor power level and for compensating the subsequent Xe concentration change. The core characteristics during load following operations are investigated in detail, using our reactor core simulator. Comparisons of changes of the Doppler reactivity, the void reactivity and the Xe reactivity during transients are performed. Also the features of Xe transient during load following operations are shown. It has been shown that the core flow change required to compensate the Xe reactivity change produces much greater change of the void reactivity than that required for power level changes, and that the resulting local power change in the lower part of the core is greater than that in the upper part, because the Xe concentration change in the lower part is hardly compensated by the core flow control. Also the effects of power level changes, cycle patterns, and initial concentration of Xe and I on the Xe transient behavior have been investigated. (author)

  6. People's response to the promotion of the effective use of nuclear power plants. From the viewpoint of favoring providing information about maintenance activities

    International Nuclear Information System (INIS)

    Sakai, Yukimi; Ueda, Yoshitaka; Goto, Manabu

    2010-01-01

    In order to elucidate people's response to the promotion of the effective use of nuclear power plants by high-reliability maintenance, we conducted a questionnaire survey targeting 306 respondents living in the cities of Kyoto, Osaka and Kobe. The questionnaire comprises information about maintenance contents and regulatory system concerning extension of plant operation cycle, long life operation, and plant power-up, not as a measure for safety but a measure for promoting effective use of power plants. It was found that a high number of respondents held a positive attitude towards the promotion of the effective use of plants, even if they tend to be anxious about safety problems. Moreover, the study suggests that no enhance the feeling of safety, information about maintenance activities and regulatory system was more effective than information about actual technical possibility. (author)

  7. Network models provide insights into how oriens–lacunosum-moleculare and bistratified cell interactions influence the power of local hippocampal CA1 theta oscillations

    Directory of Open Access Journals (Sweden)

    Katie A Ferguson

    2015-08-01

    Full Text Available Hippocampal theta is a 4-12 Hz rhythm associated with episodic memory, and although it has been studied extensively, the cellular mechanisms underlying its generation are unclear. The complex interactions between different interneuron types, such as those between oriens--lacunosum-moleculare (OLM interneurons and bistratified cells (BiCs, make their contribution to network rhythms difficult to determine experimentally. We created network models that are tied to experimental work at both cellular and network levels to explore how these interneuron interactions affect the power of local oscillations. Our cellular models were constrained with properties from patch clamp recordings in the CA1 region of an intact hippocampus preparation in vitro. Our network models are composed of three different types of interneurons: parvalbumin-positive (PV+ basket and axo-axonic cells (BC/AACs, PV+ BiCs, and somatostatin-positive OLM cells. Also included is a spatially extended pyramidal cell model to allow for a simplified local field potential representation, as well as experimentally-constrained, theta frequency synaptic inputs to the interneurons. The network size, connectivity, and synaptic properties were constrained with experimental data. To determine how the interactions between OLM cells and BiCs could affect local theta power, we explored a number of OLM-BiC connections and connection strengths.We found that our models operate in regimes in which OLM cells minimally or strongly affected the power of network theta oscillations due to balances that, respectively, allow compensatory effects or not. Inactivation of OLM cells could result in no change or even an increase in theta power. We predict that the dis-inhibitory effect of OLM cells to BiCs to pyramidal cell interactions plays a critical role in the power of network theta oscillations. Our network models reveal a dynamic interplay between different classes of interneurons in influencing local theta

  8. Medicare Provider Data - Hospice Providers

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Hospice Utilization and Payment Public Use File provides information on services provided to Medicare beneficiaries by hospice providers. The Hospice PUF...

  9. Reactive Kripke semantics

    CERN Document Server

    Gabbay, Dov M

    2013-01-01

    This text offers an extension to the traditional Kripke semantics for non-classical logics by adding the notion of reactivity. Reactive Kripke models change their accessibility relation as we progress in the evaluation process of formulas in the model. This feature makes the reactive Kripke semantics strictly stronger and more applicable than the traditional one. Here we investigate the properties and axiomatisations of this new and most effective semantics, and we offer a wide landscape of applications of the idea of reactivity. Applied topics include reactive automata, reactive grammars, rea

  10. The impact of fuel temperature reactivity coefficient on loss of reactivity control accident

    International Nuclear Information System (INIS)

    Park, J. H.; Ryu, E. H.; Song, Y. M.; Jung, J. Y.

    2012-01-01

    Nuclear reactors experience small power fluctuations or anticipated operational transients during even normal power operation. During normal operation, the reactivity is mainly controlled by liquid zone controllers, adjuster rods, mechanical control absorbers, and moderator poison. Even when the reactor power is increased abruptly and largely from an accident and when reactor control systems cannot be actuated quickly due to a fast transient, the reactor should be controlled and stabilized by its inherent safety parameter, such as a negative PCR (Power Coefficient of Reactivity) feedback. A PWR (Pressurized Water Reactor), it is well designed for the reactor to have a negative PCR so that the reactor can be safely shut down or stabilized whenever an abrupt reactivity insertion into the reactor core occurs or the reactor power is abruptly increased. However, it is known that a CANDU reactor has a small amount of PCR, as either negative or positive, because of the different design basis and safety concepts from a PWR. CNSC's regulatory and safety regime has stated that; The PCR of CANDU reactors does not pose a significant risk. Consistent with Canadian nuclear safety requirements, nuclear power plants must have an appropriate combination of inherent and engineered safety features incorporated into the design of the reactor safety and control systems. A reactor design that has a PCR is quite acceptable provided that the reactor is stable against power fluctuations, and that the probability and consequences of any potential accidents that would be aggravated by a positive reactivity feedback are maintained within CNSCprescribed limits. Recently, it was issued licensing the refurbished Wolsong unit 1 in Korea to be operated continuously after its design lifetime in which the calculated PCR was shown to have a small positive value by applying the recent physics code systems, which are composed of WIMS IST, DRAGON IST, and RFSP IST. These code systems were transferred

  11. Surface treatment of diamond-like carbon films by reactive Ar/CF{sub 4} high-power pulsed magnetron sputtering plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Takashi, E-mail: t-kimura@nitech.ac.jp [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Nishimura, Ryotaro [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Azuma, Kingo [Department of Electrical Engineering and Computer Sciences, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Nakao, Setsuo; Sonoda, Tsutomu; Kusumori, Takeshi; Ozaki, Kimihiro [National Institute of Advanced Industrial Science and Technology (AIST) - Chubu, 2266-98 Anagahora, Moriyama, Nagoya 463-8560 (Japan)

    2015-12-15

    Surface modification of diamond-like carbon films deposited by a high-power pulsed magnetron sputtering (HPPMS) of Ar was carried out by a HPPMS of Ar/CF{sub 4} mixture, changing a CF{sub 4} fraction from 2.5% to 20%. The hardness of the modified films markedly decreased from about 13 to about 3.5 GPa with increasing CF{sub 4} fraction, whereas the water contact angle of the modified films increased from 68° to 109° owing to the increase in the CF{sub x} content on the film surface. C 1s spectra in X-ray photoelectron spectroscopy indicated that a graphitic structure of modified films was formed at CF{sub 4} fractions less than 5%, above which the modified films possessed a polymer-like structure. Influence of treatment time on the properties of the modified films was also investigated in the range of treatment time from 5 to 30 min. The properties of the modified films did not depend on the treatment time in the range of treatment time longer than 10 min, whereas the water contact angle was not sensitive to the treatment time at any treatment time.

  12. Selección de los parámetros técnicos de los compensadores escalonados de potencia reactiva a nivel global; Selection of the technical parameters for the staggered compensators of reactive power at global level

    Directory of Open Access Journals (Sweden)

    Davel Borges Vasconcellos

    2011-02-01

    Full Text Available En los sistemas eléctricos industriales es muy frecuente la existencia de cargas variables. La compensacióndel factor de potencia en la mayoría de estos casos, se realiza por medio de dispositivos compensadoresestáticos que proporcionan una potencia reactiva diferente en función de las necesidades de los receptoresdel sistema.  Tales pueden ser: de compensación continua o de compensación discreta o escalonada.Estos últimos han sido ampliamente difundidos por sus ventajas. Sin embargo, los criterios para laselección de los parámetros técnicos del dispositivo, no siempre han sido adecuados. En el trabajo sepresenta un procedimiento a la hora de seleccionar dichos parámetros a nivel global en los mayormenteconocidos como compensadores automáticos del factor de potencia. Paralelamente se discute un ejemploreal de aplicación al sistema eléctrico de un pequeño taller de producción.  TIn the industrial electric systems it is very frequent the existence of variables loads. The power factorcompensation in most of these cases is carried out by means of static compensations devises thatprovide a different reactive power in function of the load demands.  Such they can be: of continuouscompensation or of discreet or staggered compensation. These last ones have been broadly diffused bytheir advantages. However, the approaches for the selection of the technical parameters they have notalways been adapted. A procedure is presented when selecting these parameters at global level in themostly well-known ones as automatic compensators of power factor. At the same time, a real example ofapplication is discusses to the electric system of a small production shop.

  13. WWER safety analysis in case of simultaneous positive reactivity introduction by control rods withdrawal and pure condensate injection

    International Nuclear Information System (INIS)

    Kuchin, A.; Ovdiienko, I.; Khalimonchuk, V.

    2011-01-01

    Results of calculation assessment of positive reactivity insertion rate are presented under condition of simultaneous effect on reactivity of two provided by WWER project reactivity operation systems - extract of regulation group and decrease of boron acid concentration. Showed that maximal positive reactivity insertion rate is achieved at hot zero power and it's too less than limit value 0.07β eff /sec defined by normative document 'Nuclear safety regulation of NPP with pressurized water reactors'. For given reasons concluded that necessity of application of the extended protection PZ-2 actuation time is absent on interval of pure condensate transportation for full exclusion of possibility of positive reactivity insertion simultaneously by two different operation systems. (Authors)

  14. Estimation of time-varying reactivity by the H∞ optimal linear filter

    International Nuclear Information System (INIS)

    Suzuki, Katsuo; Shimazaki, Junya; Watanabe, Koiti

    1995-01-01

    The problem of estimating the time-varying net reactivity from flux measurements is solved for a point reactor kinetics model using a linear filtering technique in an H ∞ settings. In order to sue this technique, an appropriate dynamical model of the reactivity is constructed that can be embedded into the reactor model as one of its variables. A filter, which minimizes the H ∞ norm of the estimation error power spectrum, operates on neutron density measurements corrupted by noise and provides an estimate of the dynamic net reactivity. Computer simulations are performed to reveal the basic characteristics of the H ∞ optimal filter. The results of the simulation indicate that the filter can be used to determine the time-varying reactivity from neutron density measurements that have been corrupted by noise

  15. Reactive perforating collagenosis

    Directory of Open Access Journals (Sweden)

    Yadav Mukesh

    2009-01-01

    Full Text Available Reactive perforating collagenosis is a rare cutaneous disorder of unknown etiology. We hereby describe a case of acquired reactive perforating collagenosis in a patient of diabetes and chronic renal failure.

  16. Reactivity on the Web

    OpenAIRE

    Bailey, James; Bry, François; Eckert, Michael; Patrânjan, Paula Lavinia

    2005-01-01

    Reactivity, the ability to detect simple and composite events and respond in a timely manner, is an essential requirement in many present-day information systems. With the emergence of new, dynamic Web applications, reactivity on the Web is receiving increasing attention. Reactive Web-based systems need to detect and react not only to simple events but also to complex, real-life situations. This paper introduces XChange, a language for programming reactive behaviour on the Web,...

  17. Monadic Functional Reactive Programming

    NARCIS (Netherlands)

    A.J. van der Ploeg (Atze); C Shan

    2013-01-01

    htmlabstractFunctional Reactive Programming (FRP) is a way to program reactive systems in functional style, eliminating many of the problems that arise from imperative techniques. In this paper, we present an alternative FRP formulation that is based on the notion of a reactive computation: a

  18. Instantaneous power theory and applications to power conditioning

    CERN Document Server

    Akagi, Hirofumi; Aredes, Mauricio

    2017-01-01

    This new edition, written by a team of experts in the field, is fully updated with information on the latest electric power technology. The instantaneous power theory, or “the p-q theory,” makes clear the physical meaning of what instantaneous real and imaginary power is in a three-phase circuit. Moreover, it provides insight into how energy flows from a source to a load, or circulates between phases, in a three-phase circuit. This theory can be used in the design and understanding of FACTS (Flexible AC Transmission System) compensators. The book introduces many concepts in the field of active filtering that are unique to this edition. It provides a study tool for final year undergraduate students, graduate students and engineers dealing ith harmonic pollution problems, reactive power compensation or power quality in general.

  19. Reactive documentation system

    Science.gov (United States)

    Boehnlein, Thomas R.; Kramb, Victoria

    2018-04-01

    Proper formal documentation of computer acquired NDE experimental data generated during research is critical to the longevity and usefulness of the data. Without documentation describing how and why the data was acquired, NDE research teams lose capability such as their ability to generate new information from previously collected data or provide adequate information so that their work can be replicated by others seeking to validate their research. Despite the critical nature of this issue, NDE data is still being generated in research labs without appropriate documentation. By generating documentation in series with data, equal priority is given to both activities during the research process. One way to achieve this is to use a reactive documentation system (RDS). RDS prompts an operator to document the data as it is generated rather than relying on the operator to decide when and what to document. This paper discusses how such a system can be implemented in a dynamic environment made up of in-house and third party NDE data acquisition systems without creating additional burden on the operator. The reactive documentation approach presented here is agnostic enough that the principles can be applied to any operator controlled, computer based, data acquisition system.

  20. Digital reactivity meter

    International Nuclear Information System (INIS)

    Akkus, B.; Anac, H.; Alsan, S.; Erk, S.

    1991-01-01

    Nowadays, various digital methods making use of microcomputers for neutron detector signals and determining the reactivity by numerical calculations are used in reactor control systems in place of classical reactivity meters. In this work, a calculation based on the ''The Time Dependent Transport Equation'' has been developed for determining the reactivity numerically. The reactivity values have been obtained utilizing a computer-based data acquisition and control system and compared with the analog reactivity meter values as well as the values calculated from the ''Inhour Equation''