WorldWideScience

Sample records for voltage overhead lines

  1. Electromagnetic Field Evaluation of a 500kV High Voltage Overhead Line

    Directory of Open Access Journals (Sweden)

    Chen Chun

    2013-02-01

    Full Text Available Many scientific articles have been written about electromagnetic field distributions under high voltage overhead transmission lines. However, some readers are still left wondering just how exactly the distribution curves formed by the fields are related to the mathematical models used. This paper presents case study results of a 500 kV alternating current overhead transmission line, and explicitly shows how the fields vary under high voltage lines by employing easily understood mathematical models. The numerical simulations, done using MATLAB, can help anyone willing to evaluate the amount of electromagnetic fields available under any other high voltage overhead transmission line. The magnitudes of the fields obtained are compared with the standard values set by the International Radiation Protection Agency so as to assess the integrity of external insulation of the line. Thus, the technical staff can easily attend to complaints that may arise about the electromagnetic field effects from the line.

  2. Wood pole overhead lines

    CERN Document Server

    Wareing, Brian

    2005-01-01

    This new book concentrates on the mechanical aspects of distribution wood pole lines, including live line working, environmental influences, climate change and international standards. Other topics include statutory requirements, safety, profiling, traditional and probabilistic design, weather loads, bare and covered conductors, different types of overhead systems, conductor choice, construction and maintenance. A section has also been devoted to the topic of lightning, which is one of the major sources of faults on overhead lines. The book focuses on the effects of this problem and the strate

  3. Composite Based EHV AC Overhead Transmission Lines

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard

    Overhead lines at transmission level are the backbone of any national power grid today. New overhead line projects however are at the same time subject to ever greater public resistance due to the lines environmental impact. As full undergrounding of transmission lines at extra high voltage (EHV...... and analysed with regard to the possibilities, limitations and risks widespread application of composite materials on EHV AC overhead transmission lines may present. To form the basis for evaluation of the useability of composite materials, dierent overhead line projects aimed at reducing the environmental...

  4. Comparison between Underground Cable and Overhead Line for a Low-Voltage Direct Current Distribution Network Serving Communication Repeater

    Directory of Open Access Journals (Sweden)

    Jae-Han Kim

    2014-03-01

    Full Text Available This paper compares the differences in economic feasibility and dynamic characteristics between underground (U/G cable and overhead (O/H line for low-voltage direct current (LVDC distribution. Numerous low loaded long-distance distribution networks served by medium-voltage alternative current (MVAC distribution lines exist in the Korean distribution network. This is an unavoidable choice to compensate voltage drop, therefore, excessive cost is expended for the amount of electrical power load. The Korean Electric Power Corporation (KEPCO is consequently seeking a solution to replace the MVAC distribution line with a LVDC distribution line, reducing costs and providing better quality direct current (DC electricity. A LVDC distribution network can be installed with U/G cables or O/H lines. In this paper, a realistic MVAC distribution network in a mountainous area was selected as the target model to replace with LVDC. A 30 year net present value (NPV analysis of the economic feasibility was conducted to compare the cost of the two types of distribution line. A simulation study compared the results of the DC line fault with the power system computer aided design/electro-magnetic transient direct current (PSCAD/EMTDC. The economic feasibility evaluation and simulation study results will be used to select the applicable type of LVDC distribution network.

  5. Analysis of Possibilities to Reduce the Voltages Induced in Multi-circuit and Multi-voltage Overhead Lines

    Directory of Open Access Journals (Sweden)

    Rafał Tarko

    2015-09-01

    Full Text Available This paper presents the issues of electromagnetic interactions in a four-circuit and dual-voltage power line. Such solutions are increasingly used in practice due to difficulties in land acquisition for the construction of new power lines. Lines of this type, however, have some disadvantages, incl. the electromagnetic interactions between the circuits and voltages induced as their consequence. These issues are considered in relation to an existing four-circuit, 110 kV and 15 kV line. Results of the studies of the interaction effects in a real system, and an analysis of selected ways to reduce the voltage induced in 15 kV line circuits are presented.

  6. Analysis of overvoltages in overhead ground wires of extra high voltage (EHV) power transmission line under single-phase-to-ground faults

    NARCIS (Netherlands)

    Dudurych, [No Value; Rosolowski, E

    2000-01-01

    Overhead ground wires (GW) of extra high voltage (EHV) power transmission lines, apart from lightning-induced overvoltage protection are frequently used for carrier-current communication. In this case the ground wires are suspended on insulators, the dielectric strength of which should be sufficient

  7. Optimization Design of an Inductive Energy Harvesting Device for Wireless Power Supply System Overhead High-Voltage Power Lines

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2016-03-01

    Full Text Available Overhead high voltage power line (HVPL online monitoring equipment is playing an increasingly important role in smart grids, but the power supply is an obstacle to such systems’ stable and safe operation, so in this work a hybrid wireless power supply system, integrated with inductive energy harvesting and wireless power transmitting, is proposed. The energy harvesting device extracts energy from the HVPL and transfers that from the power line to monitoring equipment on transmission towers by transmitting and receiving coils, which are in a magnetically coupled resonant configuration. In this paper, the optimization design of online energy harvesting devices is analyzed emphatically by taking both HVPL insulation distance and wireless power supply efficiency into account. It is found that essential parameters contributing to more extracted energy include large core inner radius, core radial thickness, core height and small core gap within the threshold constraints. In addition, there is an optimal secondary coil turn that can maximize extracted energy when other parameters remain fixed. A simple and flexible control strategy is then introduced to limit power fluctuations caused by current variations. The optimization methods are finally verified experimentally.

  8. Analysis of GIS data to investigate natural resource impacts of high-voltage overhead lines in the examples in Lower Saxony and North Rhine-Westphalia

    Energy Technology Data Exchange (ETDEWEB)

    Thinh, Nguyen Xuan; Sander, Leon; Kopec, Jakob; Muehlnickel, Kai [Technische Univ. Dortmund (Germany). Dept. of Spatial Information Management and Modelling

    2013-07-01

    In this paper we describe shortly Lower Saxony and North Rhine-Westphalia as study areas and the legal framework, both in the context of natural resource impacts of high-voltage overhead lines. We then conduct the buffer analysis of a GIS dataset in order to investigate natural resource impacts of existing high-voltage overhead lines in the two mentioned study areas. The paper is based upon the first results of the interdisciplinary research and development project ''Power Network Planning'' funded as part of the 6th Energy research program ''Research for an environmentally friendly, reliable and affordable energy supply'' by the German Federal Ministry of Economics and Technology (BMWi). (orig.)

  9. Composite Materials in Overhead Lines

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard; Holbøll, Joachim

    2009-01-01

    The use of composite materials, e.g. fibreglass materials, in overhead transmission line systems is nothing new. Composite based insulators have been applied to transmission lines for over 30 years, mainly as suspension and post insulators and often as an option for special applications. Also...... towers and recently conductors based on composite materials are available at transmission levels. In this paper it is investigated which composite based solutions are available in connection with complete overhead line systems including insulators, towers and conductors. The components are reviewed...... with respect to solved and persisting known failures/problems of both mechanical and electrical nature. Major challenges related to extensive use of composite materials in an overhead line system are identified, as are possible benefits - both when using standard as well as customised composite components, e...

  10. Living near overhead high voltage transmission power lines as a risk factor for childhood acute lymphoblastic leukemia: a case-control study.

    Science.gov (United States)

    Sohrabi, Mohammad-Reza; Tarjoman, Termeh; Abadi, Alireza; Yavari, Parvin

    2010-01-01

    This study aimed to investigate association of living near high voltage power lines with occurrence of childhood acute lymphoblastic leukemia (ALL). Through a case-control study 300 children aged 1-18 years with confirmed ALL were selected from all referral teaching centers for cancer. They interviewed for history of living near overhead high voltage power lines during at least past two years and compared with 300 controls which were individually matched for sex and approximate age. Logistic regression, chi square and paired t-tests were used for analysis when appropriate. The case group were living significantly closer to power lines (Plines (Plines against more than 600 meters. This ratio estimated as 9.93 (95%CI: 3.47 to 28.5) for 123 KV, 10.78 (95%CI: 3.75 to 31) for 230 KV and 2.98 (95%CI: 0.93 to 9.54) for 400 KV lines. Odds of ALL decreased 0.61 for every 600 meters from the nearest power line. This study emphasizes that living close to high voltage power lines is a risk for ALL.

  11. Assessment of Human Exposure to Magnetic Field from Overhead High Voltage Transmission Lines in a City in South Western Nigeria

    OpenAIRE

    Ponnle Akinlolu; Adedeji Kazeem

    2015-01-01

    The increase in electricity consumption, population, and land use has now forced high voltage transmission lines (HVTLs) either to pass or be installed around or through urban cities. This increases the level of human exposure to electromagnetic field radiation as this field produced around the HVTLs extends outwards covering some distance. This may cause a number of health hazards. It is even dangerous to a human who touch any metallic object in proximity of the HVTL, as it may have an appre...

  12. Feasibility of high-speed power line carrier system to Japanese overhead low voltage distribution lines; Teiatsu haidensen hanso no kosokuka no kanosei (hanso sningo denpa purogram no kanosei)

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, T.; Takeshita, K.; Ishino, R.

    2000-06-01

    The high-speed distribution line carrier systems on underground distribution lines are being developed in Germany. To estimate these systems on Japanese overhead low voltage distribution lines, the Carrier Propagation Program has been developed and applicability of OFDM system was roughly estimated. 1. Carrier Propagation Program Carrier Propagation Program that calculates the carrier propagation characteristics of any line structure was developed. 2. Carrier propagation characteristics Carrier propagation characteristics on typical Japanese overhead low voltage distribution lines were calculated 3.Rough estimation of OFDM system Electric fields caused by carrier at near point were calculated on the basis on carrier propagation characteristics. Results of rough estimation are as follows: - Electric field caused by carrier of more than 2Mbps system exceeds the value of the regulation. (author)

  13. Assessment of Human Exposure to Magnetic Field from Overhead High Voltage Transmission Lines in a City in South Western Nigeria

    Directory of Open Access Journals (Sweden)

    Ponnle Akinlolu

    2015-05-01

    Full Text Available The increase in electricity consumption, population, and land use has now forced high voltage transmission lines (HVTLs either to pass or be installed around or through urban cities. This increases the level of human exposure to electromagnetic field radiation as this field produced around the HVTLs extends outwards covering some distance. This may cause a number of health hazards. It is even dangerous to a human who touch any metallic object in proximity of the HVTL, as it may have an appreciable voltage induced on it due to inductive, capacitive or resistive interference from the line. This paper evaluates the magnetic field produced at mid-span by a 132kV, and a 330kV, 50Hz adjacent HVTLs with horizontal and vertical configuration in Akure, a city in South Western Nigeria using analytical method from electromagnetic field theory. This is then compared to the recommended standard limit of public exposure to magnetic field. The results of the computation showed that currently, the general public exposure to the magnetic field along the HVTLs is safe. However, right of way (ROW along the power lines is being violated as buildings and work places exist within the ROW.

  14. 现代架空线输电系统中的高压电缆段%Aspects of High Voltage Cable Sections in Modern Overhead Line Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Electrical power transmission is dominated by overhead line systems at present. This is mainly based on more than hundred years of experience of utilities in running overhead lines. Furthermore, overhead lines have proven their operational reliability and functional assurance. In the past, cables were used in distribution networks in urban areas for the most part with the exception of direct current submarine cables. New developments of high voltage XLPE cables make it possible to use this technology for EHV level applications in transmission networks. Within this paper, mixed network configurations, consisting of overhead lines and high voltage cables, are investigated. An exemplary EHV transmission line with a total length of about 100 km, which is quite typical for Central Europe, has been studied. Several different line combinations are discussed with varied rates between overhead line sections and cable sections length in practice. The length of the cable sections are ranging from several kilometers up to lengths of 100 km. In this paper the work focuses on the transient behavior of combined 400 kV overhead and cable lines during switching processes and lightning impacts. A number of calculations were carried out to get an overview of the transient stress in numerous network nodes along the transmission system. Numerical programs like ATP/EMTP have been used for these simulations. Peak values and wave shapes of the transient voltage stress have been evaluated, based on different systems and within possible combinations. In respect of the insulation coordination and transient stress at network nodes, the voltage-time trends are also analyzed. The combination of high voltage overhead and cable transmission systems, especially such with lengths of more than about 50 km, are making tightened and extended demands to the network design, to the operational management and of course to the network protection also. As an output of this investigations, the results might

  15. Reliability of lightning resistant overhead distribution lines

    Energy Technology Data Exchange (ETDEWEB)

    Tolbert, L.M.; Cleveland, J.T.; Degenhardt, L.J.

    1995-04-01

    An assessment of the 32 year historical reliability of the 13.8 kV electrical distribution system at the Oak Ridge National Laboratory (ORNL) in Tennessee has yielded several conclusions useful In the planning of Industrial power Systems. The system configuration at ORNL has essentially remained unchanged in the last 32 years which allows a meaningful comparison of reliability trends for the plant`s eight overhead distribution lines, two of which were built in the 1960`s with lightning resistant construction techniques. Meticulous records indicating the cause, duration, and location of 135 electric outages in the plant`s distribution system have allowed a reliability assessment to be performed. The assessment clearly shows how differences in voltage construction class, length, age, and maximum elevation above a reference elevation influence the reliability of overhead power distribution lines. Comparisons are also made between the ORNL historical data and predicted failure rates from ANSI and IEEE industry surveys.

  16. Computer-based mechanical design of overhead lines

    Science.gov (United States)

    Rusinaru, D.; Bratu, C.; Dinu, R. C.; Manescu, L. G.

    2016-02-01

    Beside the performance, the safety level according to the actual standards is a compulsory condition for distribution grids’ operation. Some of the measures leading to improvement of the overhead lines reliability ask for installations’ modernization. The constraints imposed to the new lines components refer to the technical aspects as thermal stress or voltage drop, and look for economic efficiency, too. The mechanical sizing of the overhead lines is after all an optimization problem. More precisely, the task in designing of the overhead line profile is to size poles, cross-arms and stays and locate poles along a line route so that the total costs of the line's structure to be minimized and the technical and safety constraints to be fulfilled.The authors present in this paper an application for the Computer-Based Mechanical Design of the Overhead Lines and the features of the corresponding Visual Basic program, adjusted to the distribution lines. The constraints of the optimization problem are adjusted to the existing weather and loading conditions of Romania. The outputs of the software application for mechanical design of overhead lines are: the list of components chosen for the line: poles, cross-arms, stays; the list of conductor tension and forces for each pole, cross-arm and stay for different weather conditions; the line profile drawings.The main features of the mechanical overhead lines design software are interactivity, local optimization function and high-level user-interface

  17. Technical reconstruction of high voltage overhead transmission lines%高压架空线路技术改造

    Institute of Scientific and Technical Information of China (English)

    牛垚宾

    2015-01-01

    Wangtaipu mine implement the power supply line transformation on the living area center substation, replaced the original cement pole for the steel tower, (hanging below 1*7-8.7-1370 galvanized steel strand) substituted the bare steel strand with the single core XLPE cable, which guarantee the safe and normal operation of the line.%王台铺矿对生活区中心变电所供电线路进行改造,采用钢管塔代替原水泥杆,单芯交联聚乙烯电缆(悬挂于1×7-8.7-1370镀锌钢绞线下方)代替裸钢绞线,保障了线路安全正常运行。

  18. Using radio frequency and ultrasonic antennas for inspecting pin-type insulators on medium-voltage overhead distribution lines

    Directory of Open Access Journals (Sweden)

    Cícero Lefort Borges

    2012-10-01

    Full Text Available This paper summarises the activities undertaken when using antennas (ultrasound and radiofrequency for identifying insulators in pre-failure state by detecting the noise emitted by the distribution line and correlating this with these insulators (porcelain pin type dielectric breakdown. This has led to developing low-cost maintenance procedures and providing support and criteria for engineer-ing decisions regarding replacing these insulators. The technique used two detectors; a radio frequency detector was used in a first investigation of a particular distribution line, set to 40 MHz and installed on the roof of a moving vehicle. The ultrasound detector was used for inspecting (phases A, B, C each structure (pole selected. Atmospheric conditions had no influence on defining pre-failure insulators (pin type based on the noise detection technique. Pin type insulators emitting noise should be replaced since measurement was made from the ground and near the base of the post.

  19. Designing concept on lightning protection of overhead power distribution line

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Shigeru [Central Research Institute of Electric Power Industry, Kanagawa-ken (Japan)], E-mail: yokoyama@criepi.denken.or.jp

    2007-07-01

    The principle is shown for lightning protection of power distribution lines taking the effects of surge arresters, overhead ground wires and their combined use into consideration. Moreover an outline of a rational design method targeting direct lightning hits, induced over voltages and back flow currents from high structures. (author)

  20. Power System Reliability Assessment by Analysing Voltage Dips on the Blue Horizon Bay 22KV Overhead Line in the Nelson Mandela Bay Municipality

    Science.gov (United States)

    Lamour, B. G.; Harris, R. T.; Roberts, A. G.

    2010-06-01

    Power system reliability problems are very difficult to solve because the power systems are complex and geographically widely distributed and influenced by numerous unexpected events. It is therefore imperative to employ the most efficient optimization methods in solving the problems relating to reliability of the power system. This paper presents a reliability analysis and study of the power interruptions resulting from severe power outages in the Nelson Mandela Bay Municipality (NMBM), South Africa and includes an overview of the important factors influencing reliability, and methods to improve the reliability. The Blue Horizon Bay 22 kV overhead line, supplying a 6.6 kV residential sector has been selected. It has been established that 70% of the outages, recorded at the source, originate on this feeder.

  1. Limiting electric fields of HVDC overhead power lines.

    Science.gov (United States)

    Leitgeb, N

    2014-05-01

    As a consequence of the increased use of renewable energy and the now long distances between energy generation and consumption, in Europe, electric power transfer by high-voltage (HV) direct current (DC) overhead power lines gains increasing importance. Thousands of kilometers of them are going to be built within the next years. However, existing guidelines and regulations do not yet contain recommendations to limit static electric fields, which are one of the most important criteria for HVDC overhead power lines in terms of tower design, span width and ground clearance. Based on theoretical and experimental data, in this article, static electric fields associated with adverse health effects are analysed and various criteria are derived for limiting static electric field strengths.

  2. Study of the frequency response of the mutual coupling between overhead lines

    Directory of Open Access Journals (Sweden)

    Selivanov V. N.

    2016-12-01

    Full Text Available The paper investigates the frequency response of the mutual coupling between multi-wire overhead lines with length comparable to the wavelengths of the highest power frequency harmonics. Deenergized overhead transmission lines are influenced by electromagnetic interference from neighboring in-service overhead lines, railway traction lines, as well as other extended conductors with currents. The voltages induced on the overhead lines are dangerous to life or health of maintenance personnel. The values of the induced voltages can be determined either by direct measurement or by calculation. The paper presents the results of experimental studies of double-circuit overhead lines of the Kola energy system. It has been shown that the frequency spectrum of the induced voltage is different from the spectrum of the source of interference, and this difference has a resonant nature. The amplitude of the voltage induced by higher harmonics can be comparable with the amplitude of the voltage induced by the power frequency. The similar results have been received in studies of influence of the AC railway traction line on adjacent overhead transmission lines. ATP-EMTP numerical analysis has been performed to receive the frequency characteristics that explain the experimental results. Preliminary estimates indicate that the cause of the phenomenon is most likely due to the resonant nature of the frequency response of the mutual coupling. The resonant nature is characterized by the interrelation of the length of overhead lines and the wavelength of the higher harmonics. A wave resonance of currents and voltages that appears in the lines lead to the "magnification" of the individual induced voltage harmonics falling in the maxima of the frequency characteristics of mutual coupling.

  3. Modeling of overhead transmission lines for lightning overvoltage calculations

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Velasco, J.A.; Castro-Aranda, F.

    2010-10-15

    This article discussed the modelling of overhead transmission lines for lightning overvoltage calculations. Such a model must include those parts of the line that get involved when a lightning return stroke hits a wire or a tower and that have some influence on the voltage developed across insulator strings. Modelling guidelines differ depending on whether the goal is to estimate overvoltages or to determine arrester energy stresses. Modelling guidelines were summarized for each component, including shield wires and phase conductors; transmission line towers; insulators; phase voltages at the instant lightning hits the line; surge arresters; and the lightning stroke. The applied Monte Carlo procedure was summarized. For line span models, a constant-parameter model generally suffices when the goal is to calculate overvoltages across insulators or to obtain the flashover rate, but a frequency-dependent parameter model is necessary to estimate the energy discharged by arresters. The model selected for representing towers can have some influence on both flashover rates and arrester energy stresses. The representation of footing impedances is critical for calculating overvoltages and arrester energy stresses, but different modelling techniques produce significantly different results. The models are limited in that the corona effect is not included in the line models, the voltages induced by the electric and magnetic fields of lightning channels to shield wires and phase conductors are neglected, and the footing models are too simple, but they are nonetheless realistic approaches for simulating lightning effects. 2 tabs., 9 figs.

  4. Broadband Transmission and Statistical Performance Properties of Overhead High-Voltage Transmission Networks

    Directory of Open Access Journals (Sweden)

    Athanasios G. Lazaropoulos

    2012-01-01

    Full Text Available This paper considers broadband signal transmission and statistical performance properties of high-voltage/broadband over power lines (HV/BPL channels associated with overhead power transmission. The overhead HV/BPL transmission channel is investigated with regard to its spectral behavior, its end-to-end signal attenuation, and its statistical performance metrics. It is found that the above features depend critically on the frequency, the overhead HV power grid type (150 kV, 275 kV, or 400 kV and single- or double-circuit, the coupling scheme applied, the physical properties of the cables used, the MTL configuration, and the type of branches existing along the end-to-end BPL signal propagation. The contribution of this paper is threefold. First, the significant broadband transmission potential of overhead HV lines is revealed. The results demonstrate that, regardless of overhead HV power grid type, the overhead HV grid is a potentially excellent communications medium, offering low-loss characteristics, flat-fading features, and low multipath dispersion over a 25 km repeater span well beyond 100 MHz. Second, regarding the statistical properties of various overhead HV/BPL transmission channels, two fundamental correlations of several wireline systems, for example, coaxial cables and xDSL, are also validated in the case of overhead HV/BPL transmission channels, namely, (i end-to-end channel attenuation in relation with root-mean-square delay spread (RMS-DS and (ii coherence bandwidth (CB in relation with RMS-DS. Third, fitting the numerical results and other field trial measurements, two regression distributions suitable for each fundamental correlation are proposed.

  5. VT VEC Primary Overhead and Underground Distribution Lines

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) Vermont Electric Cooperative, Inc. (VEC) Primary Overhead and Underground Distribution Lines. VEC’s Distribution lines were drawn from pole to...

  6. Switching overvoltage when disconnecting a combined 400 kVcable/overhead line with permanently connected shunt reactor

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Søgaard, Kim

    2008-01-01

    This paper demonstrates the results from a detailed study of the dynamic behavior of a shunt reactor compensated 400 kV combined cable/overhead line. This is accomplished by means of theoretical considerations, simulations and measurements. The work presented here is based on a real-life operating...... 400 kV power system and initiated by Danish TSO Energinet.dk after having measured the voltage of the cable/overhead line after disconnection. A particular decaying dynamic phase voltage containing voltages higher than the voltage before disconnection appeared. A simulation model for the entire system...

  7. Overhead three-phase transmission lines - Non-diagonalizable situations

    Energy Technology Data Exchange (ETDEWEB)

    Faria, J.A.B. (Centro de Electrotecnia da U.T.L. - Instituto Superior Tecnico, 1096 Lisboa (PT))

    1988-10-01

    Physically realizable transmission lines exist to which the standard modal theory does not apply since the ZY diagonalization cannot always be undertaken successfully. In this paper the non-diagonalizing conditions for typical overhead three-phase lines are established. Algorithms are described and implemented to synthesize concrete non-diagonalizable configurations, numerical examples being presented and discussed.

  8. Numerical Calculation of Overhead Power Lines Dynamics

    Directory of Open Access Journals (Sweden)

    Gogola Roman

    2016-11-01

    Full Text Available This paper contains results of transient analysis of airflow around the ACSR power line cross-section in unsymmetric multi-span. The forces applied to the power line are obtained from CFD simulations, where the wind induced vibration is studied. Effect of these forces to the maximal displacement of the power line and the maximal mechanical forces in the points of attachment are studied and evaluated.

  9. PROPAGATION BEHAVIOUR OF OVERHEAD TRANSMISSION LINES

    African Journals Online (AJOL)

    2004-02-27

    Feb 27, 2004 ... Department of Electrical Engineering, Ahmadu Bello University, Zaria, Nigeria. ... Goschler(l 983) described a practical application of data networks utilising power lines during and after the ... The principle is extended to load.

  10. Lightning Performance on Overhead Distribution Lines : After Improvement Field Observation

    Directory of Open Access Journals (Sweden)

    Reynaldo Zoro

    2009-11-01

    Full Text Available Two feeders of 20 kV overhead distribution lines which are located in a high lightning density area are chosen to be observed as a field study due to their good lightning performance after improvement of lightning protection system. These two feeders used the new overhead ground wire and new line arrester equipped with lightning counter on the main lines. The significant reduced of lines outages are reported. Study was carried out to observe these improvements by comparing to the other two feeders line which are not improved and not equipped yet with the ground wire and line arrester. These two feeders located in the nearby area. Two cameras were installed to record the trajectory of the lightning strikes on the improved lines. Lightning peak currents are measured using magnetic tape measurement system installed on the grounding lead of lightning arrester. Lightning overvoltage calculations are carried out by using several scenarios based on observation results and historical lightning data derived from lightning detection network. Lightning overvoltages caused by indirect or direct strikes are analyzed to get the lightning performance of the lines. The best scenario was chosen and performance of the lines were improved significantly by installing overhead ground wire and improvement of lightning arrester installation.

  11. Design of 1000-kV AC Single-Circuit Overhead Transmission Line

    Institute of Scientific and Technical Information of China (English)

    Li

    2010-01-01

    The UHVAC 1 000-kV transmission system is so far the one with the most advanced transmission technique applied and highest operation voltage. There are no guidelines or standards available for the design of 1 000-kV overhead transmission line in China. Study on key technologies and design schemes shall be carried out to ascertain the technical principles and construction standards for project construction, which are presented in this paper based on the Southeast Shanxi-Nanyang-Jingmen test and demonstration transmission line. A comparison and analysis of technical data and economic indices between UHV line and other lines are also described.

  12. Analysis and simulation of switching surge generation when disconnecting a combined 400 kV cable/overhead line with shunt reactor

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Wiechowski, Wojciech Tomasz; Søgaard, Kim

    2007-01-01

    400 kV power system and initiated by Danish TSO Energinet.dk after having measured the voltage of the cable/overhead line after disconnection. A particular decaying dynamic phase voltage containing voltages higher than the voltage before disconnection appeared. A simulation model for the entire system...

  13. Novel Auto-Reclosing Blocking Method for Combined Overhead-Cable Lines in Power Networks

    Directory of Open Access Journals (Sweden)

    Ricardo Granizo Arrabé

    2016-11-01

    Full Text Available This paper presents a novel auto-reclosing blocking method for combined overhead-cable lines in power distribution networks that are solidly or impedance grounded, with distribution transformers in a delta connection in their high-voltage sides. The main contribution of this new technique is that it can detect whether a ground fault has been produced at the overhead line side or at the cable line side, thus improving the performance of the auto-reclosing functionality. This localization technique is based on the measurements and analysis of the argument differences between the load currents in the active conductors of the cable and the currents in the shields at the cable end where the transformers in delta connection are installed, including a wavelet analysis. This technique has been verified through computer simulations and experimental laboratory tests.

  14. Analysis and Identification of Corona Parameters on Overhead Power Lines in Case of Direct Lightning Strikes

    Institute of Scientific and Technical Information of China (English)

    Bajorek J; Maslowski G; Ziemba R

    2013-01-01

    This paper presents a method for determining specific models of overhead power lines with presence of corona phenomenon.The obtained models provide stable numerical solutions for computer simulation of transients caused by direct lightning strikes.The corona nonlinear charge-voltage characteristics obtained from experimental tests are used for identification of the corona parameters based on System Identification Toolbox implemented in Matlab package.Different transfer functions,which give the same waveshapes of overvoltages are determined using two parametric models.A circuit representation of the obtained transfer functions is proposed and the corona model is implemented in the EMTP-RV as a hierarchical structure composed of a overhead power line divided into sections with corona branches.Some computer simulations of lightning overvoltages propagated in a typical 220 kV power line due to direct lightning strikes to a line tower are presented.The proposed method and the model implemented in EMTP-RV are still valid for multi-conductor lines and for higher voltages of power lines but new corona nonlinear charge-voltage characteristics are required as an input parameter for the identification procedure.

  15. Lightning simulation of a combined overhead line/cable connected GIS

    DEFF Research Database (Denmark)

    Kessel, Jakob; Atlason, Vioir; Bak, Claus Leth;

    2008-01-01

    at the surge arrester grounding in the overhead line/cable transition and different length of the connection cable between the transformer and the GIS busbar with a SA implemented. Those simulations are conducted for different positions of the circuit breaker present at the GIS busbar. The lightning current...... required to cause inadmissible voltages at the transformer is evaluated and the MTBF is found for different cases. With the circuit breaker at the GIS busbar in closed position results indicate that SF does not cause inadmissible voltages to appear at the trasformer. However, BFO caused by a lightning...... stroke of extremely high magnitude can cause inadmissible voltages to appear at the transformer. With the circuit breaker at the GIS busbar in open position results indicate that both SF and BFO can cause inadmissible voltages to appear at the tranformer. A risk assessment based on the simulation results...

  16. Dynamic Line Rating - Technologies and Challenges of PMU on Overhead Lines: A Survey

    DEFF Research Database (Denmark)

    Alvarez, David; Rosero, Javier; Silva, Filipe Miguel Faria da

    2016-01-01

    for line rating computation and monitoring are identified, these are: sensors, communications, management information system and information analysis tools, which are part of integral dynamic line rating systems. Finally, the benefits and challenges of using phasor measurement units for real time capacity......This article reviews direct and indirect methods developed for dynamic line rating on overhead lines, and their applications (reduction of bottlenecks, congestion costs, load shedding, among others) in the operation and control of power systems as smart grid technology. Besides, four elements...... estimation on overhead lines are analyzed, highlighting the impact of weather changes along the entire line....

  17. Mechanical Calculation of Power Lines and Strands in Overhead Transmission Lines

    Directory of Open Access Journals (Sweden)

    Li Yongping

    2016-01-01

    Full Text Available This paper discusses the issue of shape and stress of overhead transmission lines. It fully considers that the conductor is subjected to axial force, shear, bending moment simultaneousiy. And the flat wire is basically in the elastic range. Because the stress is the strength of a certain point, the bending rigidity of the overhead lines can not be ignored. However, the catenary has been used in previous research and the force of the overhead lines is obtained on this basis. The author establishes a model of wire calculation under real condition, and gives a feasible simplified model. And then it gives the line shape formula, internal force formula, formula of stress in the strands. The results show that the original stress is significantly smaller.In this paper, the stress formula is almost close to the reality. It proves the reliability of the simplified model that the line shape includes the original flexible part.The results can not only fill the gaps in the theoretical study of the overhead lines, but also have some guidance to the production and design of overhead lines.

  18. Damageability of overhead lines during ice storms in Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Turbin, S. [Donbas National Academy of Civil Engineering and Architecture, Makeyevka, Donetsk (Ukraine); Grimud, G. [NEC Ukrenergo, Kiev (Ukraine)

    2005-07-01

    Statistical data of an icing event in the Ukraine where significant failures in overhead transmission occurred were presented. The icing event led to the damage of 20,931 overhead lines (OHLs). Approximately 3420 conductors were destroyed. Nearly 4 million people lived without electricity, heat, gas and water supplies for over a week, and in some cases for nearly 4 months. Most of the ice was deposited within 10 to 12 hours, and covered an area of over 226,000 square kilometers. Damage was compounded in some areas due to winds with a mean speed of 14-17 m/s. The density of ice deposits was estimated at over 800 kilograms per cubic meter. It was determined that the OHL damages sustained in icing events can be attributed mostly to the lack of codes and regulations in the design process, as well as the absence of ice melting devices, emergency stocks of towers, cables and wires. It was noted that at the time of the storm, methods for calculating ice loads and changes in ice thickness above ground level and from the diameter of conductors proved to be inaccurate. Unbalanced icing on conductors led to the collapse of towers, and cascade damages were caused by the absence of anti-cascade towers and devices. It was suggested that the use of prevention methods such as the reduction of insulator carrying capacity may have prevented tower damage. It was concluded that since the icing event, new Ukrainian rules and regulations for the design of OHLs have been put into place, and rules for OHL exploitation were determined. Automated icing monitoring systems to predict icing and wind events have been installed. Ice melting equipment, and emergency stocks of towers, cables, wires and new methods for the erection of towers are also being used. 2 refs., 3 tabs., 9 figs.

  19. Overhead Transmission Lines Deicing under Different Incentive Displacement

    Directory of Open Access Journals (Sweden)

    Qing He

    2014-01-01

    Full Text Available Overhead transmission line icing is one of the main factors affecting safety and reliability of power grid. This paper proposed an excitation deicing method of iced wire and theoretically revealed the ice removal mechanism under displacement excitation conditions, by taking the LGJ-70/10 glaze icing wire as the 3D model and analyzing and studying its dynamic response under the effect of displacement excitation. The simulation results show that the stress of wire icing area is enlarged with the increase of excitation displacement and frequency. Through the comparison of the compression strength experimental results on a series of different iced wires in low temperature environment, the authors found out that the stress generated from the wire icing area is greater than the crushing strength of the ice within the scope of the calculation parameters, which proved the validity and the feasibility of the method, and finally the suitable excitation displacement is determined. Following studies show that, as far as possible, it is necessary to reduce the incentive displacement and also to select the appropriate constraint length in order to avoid the line jumping that may be caused by large span ice shedding.

  20. Structural health monitoring of compression connectors for overhead transmission lines

    Science.gov (United States)

    Wang, Hong; Wang, Jy-An John; Swindeman, Joseph P.; Ren, Fei; Chan, John

    2017-04-01

    Two-stage aluminum conductor steel-reinforced (ACSR) compression connectors are extensively used in US overhead transmission lines. The connectors are made by crimping a steel sleeve onto a steel core and an aluminum sleeve over electrical conducting aluminum strands. The connectors are designed to operate at temperatures up to 125°C, but their performance is increasingly degrading because of overloading of lines. Currently, electric utilities conduct routine line inspections using thermal and electrical measurements, but these methods do not provide information about the structural integrity of connectors. In this work, structural health monitoring (SHM) of compression connectors was studied using electromechanical impedance (EMI) analysis. Lead zirconate titanate (PZT)-5A was identified as a smart material for SHM. A flexible high-temperature bonding layer was used to address challenges in PZT integration due to a significant difference in the coefficients of thermal expansion of PZT and the aluminum substrate. The steel joint on the steel core was investigated because it is responsible for the ultimate tensile strength of the connector. Tensile testing was used to induce structural damage to the joint, or steel core pullout, and thermal cycling introduced additional structural perturbations. EMI measurements were conducted between the tests. The root mean square deviation (RMSD) of EMI was identified as a damage index. The use of steel joints has been shown to enable SHM under simulated conditions. The EMI signature is sensitive to variations in structural conditions. RMSD can be correlated to the structural health of a connector and has potential for use in the SHM and structural integrity evaluation.

  1. Medium-voltage Overhead Lines Connection Mode Analysis Based on Short Segment%基于小分段的中压架空线接线模式分析

    Institute of Scientific and Technical Information of China (English)

    冯霜; 王主丁; 周建其; 张代红; 孙峰

    2013-01-01

    The close coordination between the number of line segments and the grid configuration, as one of the means of improving distribution network reliability, can significantly reduce the power outage time of users.Based on the research on reliability and economy parameters, a kind of high reliability segment rule is proposed with the grid economy and reliability considered together, and then a connection mode of short segments is presented.The result shows that, compared with domestic habitual segments (3 to 5), the number of segments has a substantial increase, so that the optimal segment number of an 10 kV line of 3~15 km is increased to 4 to 18 and the system's average interruption duration index with a tie-connection decreases from 3.53~17.63 h with no segments to 0.67~2.19 h with optimal segments, greatly improving the power supply reliability with the economic benefit guaranteed.Finally, a sensitivity analysis for the segment related parameters is performed.The outcome shows that the optimal segment number of a medium-voltage distribution line is greatly related to the price of a breaker/switch, the average planned outage rate, the energy loss cost and load distribution mode along the feeder.%线路分段数量与网架的紧密配合作为提高配电网可靠性手段之一,可以明显减少用户停电时间.文中在对可靠性与经济参数调研的基础上,将经济性和可靠性结合在一起,提出了一种高可靠性分段原则,继而提出了“小分段”的接线模式.研究表明,与国内习惯分段数(3~5段)相比,线路的分段数量大幅度增加,3~15 km的10 kV线路最优分段数增加为4~18段,有联络接线模式下系统平均停电持续时间指标从无分段的3.53~17.63 h减小到分段后的0.67~2.19 h,在保证社会经济效益的前提下显著提高了供电可靠性.最后,对影响最优分段数的参数进行了灵敏度分析,结果表明中压配电线路的最优分段数受到负荷开关单价

  2. Lightning in hybrid cable-overhead lines and consequent transient overvoltages

    DEFF Research Database (Denmark)

    Silva, Filipe Miguel Faria da; Schultz Pedersen, Kasper; Bak, Claus Leth

    2017-01-01

    Whereas lines that consist entirely of underground cable are naturally protected from lightning, the phenomenon must be considered for lines that are a mix of overhead lines and underground cables. The difference between overhead lines and underground cables wave impedances may lead to transient...... overvoltages caused by reflections at the transitions points. This paper explains the phenomenon and analyses the influence of modelling Corona effect, the grounding of the towers and of the cable’s screen on the overvoltage magnitude. The analysis is made both for direct strokes on the overhead line phase......, Transient Overvoltages...

  3. Accidents by electrical contact of heavy vehicles with the power distribution network overhead lines

    Energy Technology Data Exchange (ETDEWEB)

    Bourkas, P.D.; Tsarabaris, P.T.; Katsanis, J.S.; Polykrati, A.D. [National Technical Univ. of Athens (Greece). School of Electrical and Computer Engineering; Koufakis, E.I. [Public Power Corp., Crete (Greece)

    2009-07-01

    This paper examined an electrical accident that occurred when a heavy vehicle came into contact with a distribution overhead primary circuit transmission line protected by an oil circuit breaker. The back part of a concrete pump truck made contact with a bare conductor on the medium voltage line located in a city. The driver sustained an electrical shock when he tried to descend from his truck and touched the metallic part of the driver's cabin at the same time his feet touched the ground. The accident occurred as a result of the conductive path created between the conductor and the earth through the body of the driver. The thermal, electromechanical, thermochemical and partial discharge breakdowns of the truck's solid insulation tires were studied. The oil circuit breaker was also investigated. Experiments demonstrated that reductions in the dielectric strength of the tires were caused by the wire mesh materials used to reinforce mechanical strength. The old tires avoided static electricity as a result of their increased friction and ohmic resistance value. Thermal breakdown of the wheel rubber occurred when the vehicle came into contact with the medium voltage conductor. It was concluded that drivers must jump away from vehicles that come into contact with transmission lines. 12 refs., 5 figs.

  4. Variation of Tower Footing Resistance on the Lightning Surge Propagation through Overhead Power Distribution Lines

    Directory of Open Access Journals (Sweden)

    MARIUT, E. L.

    2016-02-01

    Full Text Available This paper deals with the analysis of the effects of electromagnetic transients generated by lightning on power distribution lines, considering the influence of tower footing resistance variation. Both types of lightning stroke, direct and induced, are considered. The model of a 20 kV three-phase overhead power distribution line is performed considering a simple line circuit with triangle canopy and 50/8 mm2 Ol-Al conductors. The model of the power distribution line is done considering a Multistory tower model. New concepts regarding lightning assessment through Electromagnetic Transients program and Finite Element Method are implemented. The simulations are performed based on a time domain analysis, considering the lightning stroke as an electromagnetic perturbation within frequency range of 10-100 kHz. A contribution to value creation is the design of the Multistory tower model, used for electromagnetic transients analysis for medium voltage power distribution lines. Excepting previous research, current study was done by considering the variation of tower footing resistance of the tower, between 4-35 ohms. The novelty of the study is the analysis of the dependency determined by the variation of tower footing resistance on the lightning surge propagation through power distribution networks and subsequent consumers.

  5. Bottlenecks reduction using superconductors in high voltage transmission lines

    Directory of Open Access Journals (Sweden)

    Daloub Labib

    2016-01-01

    Full Text Available Energy flow bottlenecks in high voltage transmission lines known as congestions are one of the challenges facing power utilities in fast developing countries. Bottlenecks occur in selected power lines when transmission systems are operated at or beyond their transfer limits. In these cases, congestions result in preventing new power supply contracts, infeasibility in existing contracts, price spike and market power abuse. The “Superconductor Technology” in electric power transmission cables has been used as a solution to solve the problem of bottlenecks in energy transmission at high voltage underground cables and overhead lines. The increase in demand on power generation and transmission happening due to fast development and linked to the intensive usage of transmission network in certain points, which in turn, lead to often frequent congestion in getting the required power across to where it is needed. In this paper, a bottleneck in high voltage double overhead transmission line with Aluminum Conductor Steel Reinforced was modeled using conductor parameters and replaced by Gap-Type Superconductor to assess the benefit of upgrading to higher temperature superconductor and obtain higher current carrying capacity. This proved to reduce the high loading of traditional aluminum conductors and allow more power transfer over the line using superconductor within the same existing right-of-way, steel towers, insulators and fittings, thus reducing the upgrade cost of building new lines.

  6. 高压架空输电线路大跨越铁塔承台基础施工%On construction of crossing iron tower pier foundation of overhead ultra-high voltage power transmission lines

    Institute of Scientific and Technical Information of China (English)

    张俊平

    2011-01-01

    In the construction of the iron tower foundation power transmission lines,the paper indicates some features,including the weak geological conditions in the foundation,the tough tasks for the pier construction,and the long construction period,the paper introduces the difficulties and features of the crossing pier foundation construction of the power transmission lines,and adopts the effective measures in the cooling cycle water pipe,the temperature checking,and the surface maintenance of the concrete internal apparatus,and achieves satisfactory effects.%针对输电线路铁塔基础施工中,大量基础存在地质条件差、承台基础施工方量大、施工周期长等特点,详细介绍了输电线路大跨越大承台基础施工的难点、特点,在混凝土内部设置冷却循环水管及温度检测、表面养护等技术方面采取了有效的措施,并取得了满意的效果。

  7. The impact of overhead lines for employees with stents

    Science.gov (United States)

    Syrek, P.; Skowron, M.

    2017-05-01

    The aim of article is to discuss interaction between stents implanted in the body of worker and harmonic magnetic field in the vicinity of electric wires. In last decades, a growing proportion of people has any devices implanted, to list: cardiac pacemakers, cardioverter - defibrillators. Recommendations of International Commision on Non-ionizing Radiation Protection (ICNIRP), and resctrictions imposed in different states, may exlude specific individuals from their duties. The autors focused on the situation, when the employee with stent, works in the immediate vicinity of overhead electric wires, cleaning with dry ice the electric insulators.

  8. Excessive magnetic field flux density distribution from overhead isolated powerline conductors due to neutral line current.

    Science.gov (United States)

    Netzer, Moshe

    2013-06-01

    Overhead isolated powerline conductors (hereinafter: "OIPLC") are the most compact form for distributing low voltage currents. From the known physics of magnetic field emission from 3-phase power lines, it is expected that excellent symmetry of the 120° shifted phase currents and where compact configuration of the 3-phase+neutral line exist, the phase current vectorial summation of the magnetic field flux density (MFFD) is expected to be extremely low. However, despite this estimation, an unexpectedly very high MFFD was found in at least three towns in Israel. This paper explains the reasons leading to high MFFD emissions from compact OIPLC and the proper technique to fix it. Analysis and measurement results had led to the failure hypothsis of neutral line poor connection design and poor grounding design of the HV-LV utility transformers. The paper elaborates on the low MFFD exposure level setup by the Israeli Environmental Protection Office which adopted a rather conservative precaution principal exposure level (2 mG averaged over 24 h).

  9. New overhead line equipment on existing structures of Great Eastern route

    Energy Technology Data Exchange (ETDEWEB)

    Willi, Urs; Wittig, Mike [Furrer + Frey AG, Berne (Switzerland)

    2009-07-01

    The Great Eastern route, from London Liverpool Street via Shenfield to Chelmsford and South-end-on-Sea is equipped with 60-year old overhead line equipment with fixed termination conductors. For the 2012 Olympics the performance and reliability of the line have to be improved for the increasing number of trains and a speed of up to 160 km/h with three pantographs per train. This busy line can only afford a limited number and duration of service suspensions which would be insufficient to allow the complete renewal of the overhead line. For this reason, a new overhead line system had to be designed which can be mounted on the existing structures. (orig.)

  10. Hydro-Quebec TransEnergie's perspective on overhead transmission line protection against lightning

    Energy Technology Data Exchange (ETDEWEB)

    Dutil, A. [Hydro-Quebec, Montreal, PQ (Canada). TransEnergie Div.

    2006-07-01

    Hydro-Quebec TransEnergie's interest in transmission line surge arresters (TLSA) was discussed. The utility conducted studies regarding the use of TLSAs to reduce outages caused by lightning in overhead transmission lines having voltages of 52 to 330 kV. It was determined that in some cases, TLSA is the only solution to reducing flashover initiated by lightning. This paper presented the results of 4 different TLSA configurations in which the impact of grounding resistance on TLSA performance was examined in an effort to determine the most effective configuration. The study revealed that lightning flashovers could be reduced by 70 per cent by installing 1 TLSA on every 2 poles of a 52 kV transmission line. The TLSA should be mounted on one pole structure and the earth wire on the unprotected poles should be removed. According to several tests conducted at Hydro-Quebec's Institut de Recherche en Electricite du Quebec (IREQ), the energy absorption capability of arresters from 4 different manufacturers proved to be at least 6 kJ/kv. The arresters failure rate was estimated to 3 per cent every time a lightning strike occurred on a transmission line. It was suggested that a 100 km long line with one pole every 60 meters should not have more than one arrester failure per year. The arresters must be installed with a mechanical device that could disconnect a failed unit from the transmission system to avoid a permanent fault on the network. It was concluded that TLSAs are useful in reducing lightning flashovers caused by lightning. However, Hydro-Quebec TransEnergie still has concerns regarding their cost, reliability, impact on line maintenance, testing difficulties in the field, mechanical stress on the conductors, and their ability to withstand dielectric behaviour under ice. tabs., figs.

  11. Insulator and Clerance Requirements in Overhead Line Transmission Systems without Shield Wires

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard; Holbøll, Joachim

    2008-01-01

    This paper theoretically examines the required insulation lengths and clearances in 400 kV overhead line systems when not making use of ground wires as lightning protection. The influence of lightning strikes to the system is investigated based on dynamic transmission line simulations of a 400 kV...

  12. Insulator and Clerance Requirements in Overhead Line Transmission Systems without Shield Wires

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard; Holbøll, Joachim

    2008-01-01

    This paper theoretically examines the required insulation lengths and clearances in 400 kV overhead line systems when not making use of ground wires as lightning protection. The influence of lightning strikes to the system is investigated based on dynamic transmission line simulations of a 400 k...

  13. Variation of Tower Footing Resistance on the Lightning Surge Propagation through Overhead Power Distribution Lines

    OpenAIRE

    MARIUT, E. L.; HELEREA, E.

    2016-01-01

    This paper deals with the analysis of the effects of electromagnetic transients generated by lightning on power distribution lines, considering the influence of tower footing resistance variation. Both types of lightning stroke, direct and induced, are considered. The model of a 20 kV three-phase overhead power distribution line is performed considering a simple line circuit with triangle canopy and 50/8 mm2 Ol-Al conductors. The model of the power distribution line is done consid...

  14. DC overhead contact line in the New Buschtunnel at the City of Aachen; Gleichstromoberleitung im Neuen Buschtunnel bei Aachen

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Steffen [Balfour Beatty Rail GmbH, Offenbach/Main (Germany); Schnadhorst, Kai [Balfour Beatty Rail GmbH, Essen (Germany); Tessun, Heinz [Balfour Beatty Rail GmbH, Muenchen (Germany)

    2008-07-01

    The previous d.c. overhead contact line of Deutsche Bahn was adapted to the current state of the art to electrify the Neuer Buschtunnel. The project was realized successfully with the new overhead contact line. An automatic short-circuiting system was installed to be able to disconnect and short-circuit the overhead contact line from remote, allowing rescue services to safely access the tunnel in case of an accident. (orig.)

  15. TWO APPROACHES TO CALCULATION OF SPLIT PHASE DANCING OF OVERHEAD ELECTRICAL TRANSMISSION LINE

    Directory of Open Access Journals (Sweden)

    I. I. Sergey

    2005-01-01

    Full Text Available The paper shows two approaches to mathematical modeling of split phase dancing of overhead electrical transmission line. The first approach is based on calculative method when a phase is in the shape of flexible elastic thread connected with rigid rods. The phase is represented with equivalent wire in the second approach. Principle of mechanics relations has been used to set combined boundary problem of split phase dynamics. Two packets of computer programs for calculation of split phase dancing of overhead (electric power line have been set up and tested.

  16. Controlled Compact High Voltage Power Lines

    Directory of Open Access Journals (Sweden)

    Postolati V.

    2016-04-01

    Full Text Available Nowadays modern overhead transmission lines (OHL constructions having several significant differences from conventional ones are being used in power grids more and more widely. Implementation of compact overhead lines equipped with FACTS devices, including phase angle regulator settings (compact controlled OHL, appears to be one of the most effective ways of power grid development. Compact controlled AC HV OHL represent a new generation of power transmission lines embodying recent advanced achievements in design solutions, including towers and insulation, together with interconnection schemes and control systems. Results of comprehensive research and development in relation to 110–500kV compact controlled power transmission lines together with theoretical basis, substantiation, and methodological approaches to their practical application are presented in the present paper.

  17. Tracing overhead transmission line corridors with regard to environmental and spatial qualities

    Directory of Open Access Journals (Sweden)

    Alenka Cof

    2005-01-01

    Full Text Available The article deals with possibilities for running the proposed overhead transmission line Okroglo-Italian border. The Slovene and Italian methods are shown as methods enabling consideration of environmental and spatial impact within the process of planning overhead transmission line corridors. The Slovene method consists of analyses of attractiveness and vulnerability, whereby the first considers those functional and economic factors that affect spatial attractiveness for overhead transmission lines. Thus we can assess the level of economic and functional suitability of alternative routes of the proposed 400 kilovolt overhead transmission line from transformation station Okroglo (Slovenia to Srednje, Golo Brdo and Vrtojba, three potential contact points on the Slovene–Italian border. In accordance with stipulations of the Law on spatial management vulnerability models were prepared, which were used to simulate the development’s potential negative environmental effects and to analyse suitability, which implies harmonisation of development and protection demands. Their result is a possible corridor that can be developed without significant conflicts. The Italian procedure was developed to trace the transmission line corridor from the Slovenian border to the transformation station in Udine. It was also applied on the Slovenian side. Three groups of factors were considered in the procedure: exclusion, repulsion, and attraction. The much simpler procedure enables comparisons, since it uses the same or at least similar spatial data. In conclusion a short commentary is added about the corridor concept as a planning tool.

  18. Evaluation of Instrumentation and Dynamic Thermal Ratings for Overhead Lines

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, A. [New York Power Authority, White Plains, NY (United States)

    2013-01-31

    In 2010, a project was initiated through a partnership between the Department of Energy (DOE) and the New York Power Authority (NYPA) to evaluate EPRI's rating technology and instrumentation that can be used to monitor the thermal states of transmission lines and provide the required real-time data for real-time rating calculations. The project included the installation and maintenance of various instruments at three 230 kV line sites in northern New York. The instruments were monitored, and data collection and rating calculations were performed for about a three year period.

  19. Overhead lines: equipments. Foundations of supports; Lignes aeriennes: materiels. Fondations des supports

    Energy Technology Data Exchange (ETDEWEB)

    Naud, D. [Reseau de Transport d' Electricite (RTE), 92 - Paris la Defense (France)

    2004-02-01

    The foundation is a buried structure which ties down in the ground the superstructure (overhead line tower). This article presents: 1 - the different categories of foundations; 2 - the selection criteria: dimensioning, safety (stability, safety, geo-technical context); 3 - the calculation method: resistance with respect to throwing down, tearing up, and compression. (J.S.)

  20. A study of the conditions for symmetry of 400 kilovolt overhead power lines (LEP)

    Energy Technology Data Exchange (ETDEWEB)

    Nador, T.; Kakasine, K.

    1981-01-01

    It is noted that the construction of individual 400 kilovolt overhead power lines (LEP) in Hungary's electric power system (EES) was conducted without consideration of the symmetrization (transposition). This made it necessary to conduct works aimed at studying the issues of electric power to consumers in the examined conditions. The results of studies at the EROTERV Institute in Hungary are cited.

  1. Interlaboratory comparison of measuring results of magnetic field near 400 kV overhead power line

    Directory of Open Access Journals (Sweden)

    Grbić Maja

    2012-01-01

    Full Text Available The paper presents a comparison of measured results of magnetic field near 400 kV overhead power lines obtained by three laboratories. This interlaboratory comparison was performed to ensure confidence in the quality of the test results. The measured results were analyzed with standard methods, using En number, based on which the evaluation of the laboratories was performed.

  2. Reduction of the visual impact of overhead transmission line systems through utilisation of line surge arresters as lightning protection

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard; Holbøll, Joachim

    2008-01-01

    in line performance and lightning protection of the nearest substations requires thorough modelling of the new line including all electrical parameters necessary for performance evaluation under all conditions. In this paper, explicit use of line surge arresters as lightning protection on the line...... of the line and the required protection level in substations. The use of line surge arresters gives the possibility to decrease the height of towers thereby improving the visual impression of the overhead line transmission systems. However the usage of line surge arresters will, dependent upon line surge...

  3. Electrical and mechanical design criteria for EHV and UHV: overhead transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    The results are presented of a program devoted to the selection of electrical and mechanical design criteria and parameters for overhead power transmission lines for ac systems rated at from 345 to 1100 kV and for dc systems rated at from 600 to 1200 kV. Information is included on the environmental effects, i.e., audible noise and electric fields, of the lines, mechanical and economic requirements, safety, failures, grounding, and lightning protection. (LCL)

  4. Analysis of Contact Characteristic of Overhead Line and Suspension Clamp

    Directory of Open Access Journals (Sweden)

    Zhao Xinze

    2013-01-01

    Full Text Available In this paper, a LGJ150/25 type ACSR transmission line and a CGU-3 type suspension clamp are taken as research objects. A contact model of the conductor and the clamp was established by using finite element method. The effects of sag angle of the conductor, holding force and tension force in section are analyzed. The results showed that the contact area in the middle of the clamp is of belt-like type. The extreme values of tress were observed on the edge of the contact area and near the edge of keeper. In clamp section, suspension angle had the greatest influence on contact stress, and then the clamp force. The tension force in section played a most important role in these affecting factors. In the exit section of clamp, the biggest impact factor was tension force in this section, then the suspension angle, the third was clamp force. The results provide theoretical basis on reducing corona loss, optimization the clamp. Doubtlessly, the conclusion has important theoretical significance and application value.

  5. Lightning discharges and discharges from overhead power lines with human burn injuries as consequences

    Directory of Open Access Journals (Sweden)

    Javor Sanja

    2013-01-01

    Full Text Available Discharges from overhead power lines and lightning discharges may severely endanger human life and health. If non-lethal, burn injuries may also last for a lifetime, so as Lichtenberg figures caused by lightning discharges. Some accidents with burns are discussed in this paper and recommendations given for safety reasons. Specific energy transferred by typical lightning strokes currents given in the standard IEC 62305 is calculated. The aim of the paper is to suggest a simple expression for the estimation of safe approach distances to overhead lines, especially if high temperatures and changes in terrain reduced the secure height above ground, or if carrying elevated objects. Results of these calculations are compared to safe approach distances given in regulations of different countries. Safe distances from railway power lines are also considered.

  6. Comparison of overhead line lightning performance based on two different tower geometries

    DEFF Research Database (Denmark)

    Ebdrup, Thomas; Olason, Daniel; Bak, Claus Leth

    2014-01-01

    As a part of reinforcing the 400 kV transmission system in Jutland, Denmark, the Danish TSO is in the process of constructing a new gas insulated substation (GIS) in Revsing. This includes raising a new type of pylon, which will carry the new overhead lines to the GIS. The reliability of the subs......As a part of reinforcing the 400 kV transmission system in Jutland, Denmark, the Danish TSO is in the process of constructing a new gas insulated substation (GIS) in Revsing. This includes raising a new type of pylon, which will carry the new overhead lines to the GIS. The reliability...... of the substation and transmission line is of great importance as it is a part of the 400 kV backbone between Sweden, Norway, Germany and the offshore wind farms in Horns Rev, Denmark. The new Eagle pylon has been designed with the focus of minimizing the visual impacted of overhead lines. A detailed lightning...

  7. A Novel Transient Fault Current Sensor Based on the PCB Rogowski Coil for Overhead Transmission Lines.

    Science.gov (United States)

    Liu, Yadong; Xie, Xiaolei; Hu, Yue; Qian, Yong; Sheng, Gehao; Jiang, Xiuchen

    2016-05-21

    The accurate detection of high-frequency transient fault currents in overhead transmission lines is the basis of malfunction detection and diagnosis. This paper proposes a novel differential winding printed circuit board (PCB) Rogowski coil for the detection of transient fault currents in overhead transmission lines. The interference mechanism of the sensor surrounding the overhead transmission line is analyzed and the guideline for the interference elimination is obtained, and then a differential winding printed circuit board (PCB) Rogowski coil is proposed, where the branch and return line of the PCB coil were designed to be strictly symmetrical by using a joining structure of two semi-rings and collinear twisted pair differential windings in each semi-ring. A serial test is conducted, including the frequency response, linearity, and anti-interference performance as well as a comparison with commercial sensors. Results show that a PCB Rogowski coil has good linearity and resistance to various external magnetic field interferences, thus enabling it to be widely applied in fault-current-collecting devices.

  8. A Novel Transient Fault Current Sensor Based on the PCB Rogowski Coil for Overhead Transmission Lines

    Directory of Open Access Journals (Sweden)

    Yadong Liu

    2016-05-01

    Full Text Available The accurate detection of high-frequency transient fault currents in overhead transmission lines is the basis of malfunction detection and diagnosis. This paper proposes a novel differential winding printed circuit board (PCB Rogowski coil for the detection of transient fault currents in overhead transmission lines. The interference mechanism of the sensor surrounding the overhead transmission line is analyzed and the guideline for the interference elimination is obtained, and then a differential winding printed circuit board (PCB Rogowski coil is proposed, where the branch and return line of the PCB coil were designed to be strictly symmetrical by using a joining structure of two semi-rings and collinear twisted pair differential windings in each semi-ring. A serial test is conducted, including the frequency response, linearity, and anti-interference performance as well as a comparison with commercial sensors. Results show that a PCB Rogowski coil has good linearity and resistance to various external magnetic field interferences, thus enabling it to be widely applied in fault-current-collecting devices.

  9. Deflection Determination of Reinforced Concrete Support Poles for Overhead Transmission Lines

    Directory of Open Access Journals (Sweden)

    M. A. Korotkevich

    2011-01-01

    Full Text Available The paper contains values of torque magnification ratio while shifting vertical loads due to horizontal wind forces affecting on supports of overhead transmission lines of 35 kV and higher. These values pertain to various types of unified reinforced concrete conic and cylindrical supports while changing climatic conditions. The values make it possible to exclude rather complicated calculations in respect of support deflection in the case when there is uncertainty in initial data.

  10. A Comparative Parametric Analysis of the Ground Fault Current Distribution on Overhead Transmission Lines

    OpenAIRE

    VINTAN, M.

    2016-01-01

    The ground fault current distribution in an effectively grounded power network is affected by various factors, such as: tower footing impedances, spans lengths, configuration and parameters of overhead ground wires and power conductors, soil resistivity etc. In this paper, we comparatively analyze, using different models, the ground fault current distribution in a single circuit transmission line with one ground wire. A parametric comparative analysis was done in order to stud...

  11. Overhead contact lines according to TSI Energy, installation design and technical acceptance; Oberleitungsanlagen nach TSI Energie. Planung und Abnahme

    Energy Technology Data Exchange (ETDEWEB)

    Schnadhorst, Kai [Balfour Beatty Rail GmbH, Essen (Germany); Tessun, Heinz [Balfour Beatty Rail GmbH, Muenchen (Germany)

    2011-04-15

    Comparison of the issues of 2002 and 2008 of the technical specification for interoperability relating to the ''energy'' sub-system of the trans-European high-speed rail system (TSI) influences, especially of the permissible wind deviation to the standard overhead contact line of Deutsche Bahn (DB). Installation design, acceptance, construction and technical approval of an overhead contact line in accordance with TSI. (orig.)

  12. Assumptions in quantitative analyses of health risks of overhead power lines

    Energy Technology Data Exchange (ETDEWEB)

    De Jong, A.; Wardekker, J.A.; Van der Sluijs, J.P. [Department of Science, Technology and Society, Copernicus Institute, Utrecht University, Budapestlaan 6, 3584 CD Utrecht (Netherlands)

    2012-02-15

    One of the major issues hampering the formulation of uncontested policy decisions on contemporary risks is the presence of uncertainties in various stages of the policy cycle. In literature, different lines are suggested to address the problem of provisional and uncertain evidence. Reflective approaches such as pedigree analysis can be used to explore the quality of evidence when quantification of uncertainties is at stake. One of the issues where the quality of evidence impedes policy making, is the case of electromagnetic fields. In this case, a (statistical) association was suggested with an increased risk on childhood leukaemia in the vicinity of overhead power lines. A biophysical mechanism that could support this association was not found till date however. The Dutch government bases its policy concerning overhead power lines on the precautionary principle. For The Netherlands, previous studies have assessed the potential number of extra cases of childhood leukaemia due to the presence over overhead power lines. However, such a quantification of the health risk of EMF entails a (large) number of assumptions, both prior to and in the calculation chain. In this study, these assumptions were prioritized and critically appraised in an expert elicitation workshop, using a pedigree matrix for characterization of assumptions in assessments. It appeared that assumptions that were regarded to be important in quantifying the health risks show a high value-ladenness. The results show that, given the present state of knowledge, quantification of the health risks of EMF is premature. We consider the current implementation of the precautionary principle by the Dutch government to be adequate.

  13. Time Granularity Transformation of Time Series Data for Failure Prediction of Overhead Line

    Science.gov (United States)

    Ma, Yan; Zhu, Wenbing; Yao, Jinxia; Gu, Chao; Bai, Demeng; Wang, Kun

    2017-01-01

    In this paper, we give an approach of transforming time series data with different time granularities into the same plane, which is the basis of further association analysis. We focus on the application of overhead line tripping. First all the relative state variables with line tripping are collected into our big data platform. We collect line account, line fault, lightning, power load and meteorological data. Second we respectively pre-process the five kinds of data to guarantee the integrality of data and simplicity of analysis. We use a representation way combining the aggregated representation and trend extraction methods, which considers both short term variation and long term trend of time sequence. Last we use extensive experiments to demonstrate that the proposed time granularity transformation approach not only lets multiple variables analysed on the same plane, but also has a high prediction accuracy and low running time no matter for SVM or logistic regression algorithm.

  14. Optimal design of lattice metal constructions of overhead power transmission lines

    Directory of Open Access Journals (Sweden)

    Pustovgar Andrey

    2016-01-01

    Full Text Available The article presents a new concept of design of power lines which allowed us to develop new unified power transmission supports, efficient and reliable ones. For the first time, a method of optimum design of overhead power lines has been developed which considered the power line as a united structural system, the relief, the atmospheric and climatic conditions, the environment pollution, the efficiency requirements, the technological and operational expenditures. The article describes the changes introduced into the requirements for the dimensions and parameters of grid metal works with the minimum mass. The optimum design, the computer-aided assembly process and the use of advanced technologies guarantee the reduction of the construction period and the increase in the maintenance period of power lines.

  15. A theoretical model of rain–wind–induced in-plane galloping on overhead transmission tower-lines system

    Directory of Open Access Journals (Sweden)

    Chao Zhou

    2015-09-01

    Full Text Available Rain–wind–induced galloping phenomenon often occurs on overhead transmission tower-lines system, just as icing galloping and vortex-excited vibration; this kind of instability oscillation can cause power-line breakage or tower failure. However, the existing theoretical models of rain–wind–induced galloping are mainly based on the hypothesis of the overhead power-lines with fixed ends, which is inconsistent with the actual operation situation. Therefore, this article thus presents a preliminary theoretical study and proposes a new theoretical model taking into account the effect of tower excitations on the in-plane galloping of the overhead power-line and on the motion of the upper rain-line. The theoretical model is solved by Galerkin method and verified by the comparison with the test data obtained in the available literature involved with the overhead power-lines with fixed towers or moving towers. It turns out that the tower excitations may intensify the in-plane galloping amplitude of the overhead power-line within a certain range of frequency ratio and enable better comprehension of rain–wind–induced galloping mechanism.

  16. Method of Calculation of Current of the Ground Faults in the Parallel Overhead Transmission Lines 110-220 Kv

    Directory of Open Access Journals (Sweden)

    Ukraintsev Alexandr V.

    2017-01-01

    Full Text Available The mutual induction between the phase wires of the different overhead lines which situate close to each other cause unbalanced redistribution of currents in the line wires. This leads to emergence of the outof-balance zero sequence current which affects negatively on the sensitivity of the zero-sequence current protection. It is impossible to estimate such out-ofbalance current by the means of the typical calculation programs for short circuit currents. This paper describes the method of “virtual” lines for an extra correction of the values of zero-sequence currents during the current ground faults happening in the overhead lines 110-220 kV. There is an example of using this method for three parallel overhead lines 220 kV passing close to each other.

  17. Deicing of medium voltage power transmission lines by Joule heating method

    Energy Technology Data Exchange (ETDEWEB)

    Farokhi, S.; Vahidi, B. [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Electrical Engineering Dept.

    2005-07-01

    A Joule heating method for the de-icing of overhead transmission lines was presented. The combined use of short circuits and reduced voltage was introduced as as effective method for the de-icing of sub-transmission lines of a utility in Iran. The method is able to melt ice in a short period of time. The required electrical current and the time needed for melting the ice as a function of wind speed, air temperature and ice thickness was determined by using a finite difference heat transfer model which considered the heat flux terms. An algorithm of the application method was proposed using the finite difference heat transfer model and considering steady state radial heat conduction. The required time for melting the accumulated ice on overhead transmission lines for different values of line current and climatic conditions was calculated. In the proposed method, after disconnecting the end of the line, a 3 phase short circuit was applied and accumulated ice was melted because of Joule losses. The main restrictions to the method were the current rating of facilities, and source capacity. After a consideration of these restrictions, instead of feeding the line by rated voltage, a voltage with a value of about 20 to 40 per cent of its rated voltage was applied and a short circuit on the end of the line should be made. The algorithm was made by collecting the data for the power system, disconnecting both ends of the line from the system and applying required changes on loads. transformers calculated from the load flow of the system. The line was fed with the reduced voltage by connecting the line to a lower level voltage. A case study of the method was presented. 10 refs., 1 tab., 4 figs.

  18. A Comparative Parametric Analysis of the Ground Fault Current Distribution on Overhead Transmission Lines

    Directory of Open Access Journals (Sweden)

    VINTAN, M.

    2016-02-01

    Full Text Available The ground fault current distribution in an effectively grounded power network is affected by various factors, such as: tower footing impedances, spans lengths, configuration and parameters of overhead ground wires and power conductors, soil resistivity etc. In this paper, we comparatively analyze, using different models, the ground fault current distribution in a single circuit transmission line with one ground wire. A parametric comparative analysis was done in order to study the effects of the non-uniformity of the towers footing impedances, number of power lines spans, soil resistivity, grounding systems resistances of the terminal substations etc., on the ground fault current distribution. There are presented some useful qualitative and quantitative results obtained through a complex dedicated developed MATLAB 7.0 program.

  19. Accurate one-end fault location for overhead transmission lines in interconnected power systems

    Energy Technology Data Exchange (ETDEWEB)

    Eisa, Amir A.A.; Ramar, K. [Faculty of Engineering, Multimedia University, 63100 Cyberjaya (Malaysia)

    2010-06-15

    This paper presents a new one-end fault location method for overhead transmission lines embedded in a general n-bus interconnected power system. High accuracy in fault location is achieved by using both an accurate distributed parameters model for the faulted transmission line, and a two-bus Thevenin equivalent network model for the power system that accurately accounts for its interconnectivity. The method has been tested using transient fault data obtained from PSCAD/EMTDC simulations of an 11-bus interconnected power system. The results obtained indicate that the method is capable of estimating the fault distance with high accuracy for various fault conditions. They also indicate that method is sensitive to errors in the value of the local bus impedance, but is insensitive to errors in the value of the remote bus impedance. (author)

  20. Autonomous Inspection Robot for Power Transmission Lines Maintenance While Operating on the Overhead Ground Wires

    Directory of Open Access Journals (Sweden)

    Zheng Li

    2011-01-01

    Full Text Available This paper describes the development of a mobile robot capable of clearing such obstacles as counterweights, anchor clamps, and torsion tower. The mobile robot walks on overhead ground wires in 500KV power tower. Its ultimate purpose is to automate to inspect the defect of power transmission line. The robot with 13 motors is composed of two arms, two wheels, two claws, two wrists, etc. Each arm has 4 degree of freedom. Claws are also mounted on the arms. An embedded computer based on PC/104 is chosen as the core of control system. Visible light and thermal infrared cameras are installed to obtain the video and temperature information, and the communication system is based on wireless LAN TCP/IP protocol. A prototype robot was developed with careful considerations of mobility. The new sensor configuration is used for the claw to grasp the overhead ground wires. The bridge is installed in the torsion tower for the robot easy to cross obstacles. The new posture plan is proposed for obstacles cleaning in the torsion tower. Results of experiments demonstrate that the robot can be applied to execute the navigation and inspection tasks.

  1. Autonomous Inspection Robot for Power Transmission Lines Maintenance While Operating on the Overhead Ground Wires

    Directory of Open Access Journals (Sweden)

    Zheng Li

    2010-12-01

    Full Text Available This paper describes the development of a mobile robot capable of clearing such obstacles as counterweights, anchor clamps, and torsion tower. The mobile robot walks on overhead ground wires in 500KV power tower. Its ultimate purpose is to automate to inspect the defect of power transmission line. The robot with 13 motors is composed of two arms, two wheels, two claws, two wrists, etc. Each arm has 4 degree of freedom. Claws are also mounted on the arms. An embedded computer based on PC/104 is chosen as the core of control system. Visible light and thermal infrared cameras are installed to obtain the video and temperature information, and the communication system is based on wireless LAN TCP/IP protocol. A prototype robot was developed with careful considerations of mobility. The new sensor configuration is used for the claw to grasp the overhead ground wires. The bridge is installed in the torsion tower for the robot easy to cross obstacles. The new posture plan is proposed for obstacles cleaning in the torsion tower. Results of experiments demonstrate that the robot can be applied to execute the navigation and inspection tasks.

  2. Rational design equations for the Aeolian vibration of overhead power lines

    Energy Technology Data Exchange (ETDEWEB)

    Lu, M.L.; Chopra, N. [BC Hydro, Burnaby, BC (Canada)

    2008-07-01

    Aeolian vibration must be considered when designing overhead power transmission lines because of its potential risk of causing fatigue failure to the conductor, hardware, and tower members. Aeolian vibration is caused by the alternate shedding of Karman vortices from the top and bottom of the line's conductor when the conductor is exposed to a side wind. This paper presented a novel approach to analytically predict the vortex-induced vibration (i.e. Aeolian vibration) of an overhead power line's single conductor due to wind. The paper described the derivation of an analytical solution to the basic problem of the Aeolian vibration of a conductor span with equivalent supports on both ends by using the energy balance principle as well as the semi-empirical equations for the wind power input and the self damping of a conductor. The paper noted that a wind's turbulence effect may also be taken into account by using a previously found analytical solution. Simple, pragmatic design equations were established for undamped conductor spans by curve-fitting the numerical data from analytical solutions. It was concluded that the complicated problem of Aeolian vibration of a single conductor without damper or with multiple dampers could be easily solved by using the analytical solutions developed in this paper and that simple, yet rational design equations have been established for the Aeolian vibration of undamped conductor spans to bridge the gap between the apparently complicated theory and the often overly simplified actual design practice. 13 refs., 1 tab., 4 figs.

  3. Multivariable time series prediction for the icing process on overhead power transmission line.

    Science.gov (United States)

    Li, Peng; Zhao, Na; Zhou, Donghua; Cao, Min; Li, Jingjie; Shi, Xinling

    2014-01-01

    The design of monitoring and predictive alarm systems is necessary for successful overhead power transmission line icing. Given the characteristics of complexity, nonlinearity, and fitfulness in the line icing process, a model based on a multivariable time series is presented here to predict the icing load of a transmission line. In this model, the time effects of micrometeorology parameters for the icing process have been analyzed. The phase-space reconstruction theory and machine learning method were then applied to establish the prediction model, which fully utilized the history of multivariable time series data in local monitoring systems to represent the mapping relationship between icing load and micrometeorology factors. Relevant to the characteristic of fitfulness in line icing, the simulations were carried out during the same icing process or different process to test the model's prediction precision and robustness. According to the simulation results for the Tao-Luo-Xiong Transmission Line, this model demonstrates a good accuracy of prediction in different process, if the prediction length is less than two hours, and would be helpful for power grid departments when deciding to take action in advance to address potential icing disasters.

  4. An ultrasonic guided wave approach for the inspection of overhead transmission line cables

    DEFF Research Database (Denmark)

    Kappatos, Vasileios; Yücel, Mehmet K.; Legg, Mathew

    2017-01-01

    Inspection of overhead transmission line cables is performed using various non-destructive testing techniques, such as visual, temperature, and eddy current-based inspection; yet each of these techniques have their respective shortcomings and safety concerns. The use of ultrasonic guided waves...... as a non-destructive testing technique is well established for simple geometries such as plates, pipes, and rods. However, its application for multi-wire cables is still in development. In this study, ultrasonic guided waves excited by a shear mode transducer collar are utilised as a defect detection...... technique for untensioned aluminium conductor steel reinforced cable specimens. The identification and analysis of wave propagation for a broad range of frequencies is performed using a laser scanning vibrometer, and the effect of defect size on wave propagation is studied. Signal processing algorithms...

  5. Laboratory Investigation on Lightning Flashes to High Voltage Transmission Lines%Laboratory Investigation on Lightning Flashes to High Voltage Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    Thongchai Disyadej; Stanislaw Grzybowski

    2011-01-01

    This paper presents an investigation on the attractive width of high voltage transmission lines to lightning strikes. In order to design the optimal lightning protection, the estimated number of lightning flashes on the line, which is based on its attractive width, needs to be determined. The investigation was performed using experiments with model tests at the Mississippi State University High Voltage Laboratory. For laboratory experiments, a total of 2,100 negative and positive switching impulse voltages were applied to transmission line models from a conducting rod, which represented a lightning downward leader. Different tested models of transmission lines on a scale of 1:100 were used. The effects of overhead ground wires, phase conductors, tower structures, and the magnitude and polarity of lightning strokes were also studied. The attractive width increased gradually with the height of overhead ground wires and towers as well as the magnitude of the lightning stroke current. Impulse polarity had an impact on the at- tractive width, and the attractive width for negative polarity was larger than that {or positive polarity. The taller tower had more effect on flash distribution to transmission lines than the shorter one. The experimental results agree with the actual transmission line observations published in literature. The new expressions for the attractive width of transmission lines, based on the experimental results, were established. The accurate estimation of the attractive width can help electric power utilities plan transmission systems reliably and economically. The detailed description of the back- ground problem, proposed method, experimental results, and analysis are presented in this paper.

  6. Fibre optics overhead lines: A state-of-the-art survey

    Energy Technology Data Exchange (ETDEWEB)

    Madge, R.C.; Krishnasamy, S.G.

    1991-12-01

    A survey was conducted to gather information on installation, operating experience, economic benefits, and other outstanding issues relating to the use of fiber optic cables as an integral part of power transmission lines. The survey focused on Canadian electric utilities but was also extended to Japan and the USA, where fiber optic cables have been in use considerably longer than in Canada. The fiber optic cables commonly used in overhead power lines can be divided into 3 major groups: composite fiber optic ground wires (OPGW), all-dielectric self-supporting (ADSS) cables, and fiber optic cables lashed to or wrapped around a metallic carrier. Canadian utilities lag significantly behind American and Japanese utilities in installed lengths of fiber optic cables of all kinds. Planned installations over the next several years will improve the Canadian situation. This delayed use may be partly due to the large distances between population and economic centers, resulting in high installation costs. Only 4 of the 13 survey participants indicated problems with use of the cables. These problems were related to improper cable design, improper performance specifications, and installation or operational deficiencies. The survey showed that OPGW and ADSS cables are increasingly considered for communications needs, but their use lags behind the more traditional technologies such as microwaves and power-line carriers. A number of issues were identified as real or perceived concerns to potential users, including lightning effects, aeolian vibration, environmental exposure, hardware design, tower placement, and a lack of shared experiential information. 5 refs., 3 figs., 3 tabs.

  7. Development of high-speed overhead contact line systems for tunnels; Entwicklung von Hochgeschwindigkeits-Oberleitungsanlagen im Tunnel. Beispiel Re 330 der Deutschen Bahn

    Energy Technology Data Exchange (ETDEWEB)

    Tessun, H. [Balfour Beatty Rail GmbH Power Systems, Muenchen (Germany)

    2005-07-01

    The high performance overhead contact line Re 330 of Deutsche Bahn is already in service on lines where no tunnels exist. The presentation shows assemblies, special developed for the use of tunnels, with regard to the line Nuernberg - Ingolstadt. (orig.)

  8. Shaping the spectra of the line-to-line voltage using signal injection in the common mode voltage

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Rasmussen, Peter Omand; Pedersen, John Kim

    2009-01-01

    A drawback of Pulse Width Modulation in electrical drives is the high harmonic content of the line to line voltages, which gives rise to Electro-Magnetic Interference and acoustic noise. By injection of a signal into the common mode voltage, the fundamental is not affected, but new frequency...... components are introduced in the line to line voltage spectrum. This paper introduces a new analytical method for estimation of the line to line voltage spectrum, where sinusoidal signal is injected into the common mode voltage. Based on the analytical calculations, also a new fixed carrier frequency quasi...

  9. Three-dimensional Model Analysis of Electric Field Excited by Multi-circuit Intersecting Overhead Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    XIAO Dongping; LEI Hui; ZHANG Zhanlong; HE Wei

    2013-01-01

    This work is carried out to predict the special distribution of electric field induced by multi-circuit intersecting overhead high-voltage (HV) transmission lines (TLs) within a large range without any expensive and time-consuming computation.The two main parts of the presented methodology are 1) setting up a three-dimensional (3D) model to calculate the electric field based on combining catenary equations with charge simulation method and 2) calculating the hybrid electric field excited by multi-circuit intersecting TLs using coordinate transformation and superposition technique.Examples of different TLs configurations,including a 220 kV single-circuit horizontally configured TLs,a 500 kV single-circuit triangularly configured TLs and a combination of the 220 kV TLs and the 550 kV TLs,are illustrated to verify the validity of this methodology.A more complicatal configurations,including a 500 kV double-circuit TLs and two 220kV single-circuit horizontally configured TLs,are also calculated.Conclusions were drawn from the simulation:1) The presented 3D model outperforms 2D models in describing the electric field distribution generated by practical HV TLs with sag and span.2) Coordinate transformation and superposition technique considerably simplify the electric field computation for multi-circuit TLs configurations,which makes it possible to deal with complex engineering problems.3) The electric field in the area covered by multiple intersecting overhead TLs is distorted and the hybrid electric field strength in some partial region increases so sharply that it might exceed the admissible value.4) The configuration parameters of the TLs and the spatial configuration of multi-circuit TLs,for instance,the height of TLs,the length of span and the intersection angle of multiple circuits,influence the strength and the distribution of hybrid electric field.The influence regularities summarized in this paper can be referred by future TL designs to meet the electromagnetic

  10. New fault location system for power transmission lines using composite fiber-optic overhead ground wire (OPGW)

    Energy Technology Data Exchange (ETDEWEB)

    Urasawa, K. (Tokyo Electric Power Co., Inc. (Japan)); Kanemaru, K.; Toyota, S.; Sugiyama, K. (Hitachi Cable, Ltd., Tokyo (Japan))

    1989-10-01

    A new fault location (FL) method using composite fiber-optic overhead ground wires (OPGWs) is developed to find out where electrical faults occur on overhead power transmission lines. This method locates the fault section by detecting the current induced in the ground wire (GW), i.e. OPGW in this system. Since detected fault information is essentially uncertain, the new FL method treats the fault information oas a current distribution pattern throughout the power line, and applies Fuzzy Theory to realize the human-like manner of fault location used by electrical power engineers. It was confirmed by computer simulations that the fault section can be accurately located using this method under various conditions. This FL system has already been applied to several commercial power transmission lines and successfully located the sections where electrical faults occurred on actual power transmission lines.

  11. Overhead power lines or underground cables? A meta-study on the criteria and results of investigations on the network extension; Freileitungen oder Erdkabelleitungen? Eine Metastudie ueber die Kriterien und Ergebnisse von Untersuchungen zum Netzausbau

    Energy Technology Data Exchange (ETDEWEB)

    Novitskiy, Alexander; Arlt, Dorothee; Wolling, Jens; Westermann, Dirk

    2012-11-01

    The question to the necessity of the extension of the high-voltage grid in Germany and to the realization of overhead power lines or underground cables has evolved to a controversial energy policy issue in the recent years. Measures for the extension of the power grids at high voltage level are complex infrastructural projects. Thus the different technology options have to be discussed on very different content-specific levels. It is especially important to find out which criteria are necessary for the evaluation. Under this aspect, the authors of the contribution under consideration report on the systematization of these criteria as well as on the current knowledge according to overhead power lines and underground cables.

  12. LED-Based High-Voltage Lines Warning System

    Directory of Open Access Journals (Sweden)

    Eldar MUSA

    2013-04-01

    Full Text Available LED-based system, running with the current of high-voltage lines and converting the current flowing through the line into the light by using a toroid transformer, has been developed. The transformer’s primary winding is constituted by the high voltage power line. Toroidal core consists of two equal parts and the secondary windings are evenly placed on these two parts. The system is mounted on the high-voltage lines as a clamp. The secondary winding ends are connected in series by the connector on the clamp. LEDs are supplied by the voltage at the ends of secondary. Current flowing through highvoltage transmission lines is converted to voltage by the toroidal transformer and the light emitting LEDs are supplied with this voltage. The theory of the conversion of the current flowing through the line into the light is given. The system, running with the current of the line and converting the current into the light, has been developed. System has many application areas such as warning high voltage lines (warning winches to not hinder the high-voltage lines when working under the lines, warning planes to not touch the high-voltage lines, remote measurement of high-voltage line currents, and local illumination of the line area

  13. Finite Element Modelling of Electrical Overhead Line Cables under Turbulent Wind Load

    Directory of Open Access Journals (Sweden)

    Dominik Stengel

    2014-01-01

    Full Text Available This paper presents a finite element model of an overhead transmission line using so called cable elements which allow reproducing the cable’s nonlinear characteristics accurately employing only a few elements. Aerodynamic damping is considered in the equation of motion by taking into account the relative velocity between the flow of the wind and the moving structure. The wind flow itself is simulated by wave superposition making necessary assumptions on the lateral correlation between the wind velocities along the cable length. As result from the simulation, the following conclusions can be drawn. The first natural frequency of generally used wide spanning cables lies well below 1 Hz where also most of the energy content of the wind excitation is to be expected. Aerodynamic damping is significant for the moving cables holding very low structural damping which leads to a suppression of resonant amplification. This is particularly of interest regarding the support reaction which is dominated by the mean value and the so called background response. The latter is mostly influenced by the randomness of the wind flow, especially lateral to the main wind direction.

  14. The Reusable Load Cell with Protection Applied for Online Monitoring of Overhead Transmission Lines Based on Fiber Bragg Grating.

    Science.gov (United States)

    Ma, Guoming; Mao, Naiqiang; Li, Yabo; Jiang, Jun; Zhou, Hongyang; Li, Chengrong

    2016-06-21

    Heavy ice coating of high-voltage overhead transmission lines may lead to conductor breakage and tower collapse causing the unexpected interrupt of power supply. The optical load cell applied in ice monitoring systems is immune to electromagnetic interference and has no need of a power supply on site. Therefore, it has become a hot research topic in China and other countries. In this paper, to solve the problem of eccentric load in measurement, we adopt the shearing structure with additional grooves to improve the strain distribution and acquire good repeatability. Then, the fiber Bragg grating (FBG) with a permanent weldable package are mounted onto the front/rear groove of the elastic element by spot welding, the direction deviation of FBGs is 90° from each other to achieve temperature compensation without an extra FBG. After that, protection parts are designed to guarantee high sensitivity for a light load condition and industrial safety under a heavy load up to 65 kN. The results of tension experiments indicate that the sensitivity and resolution of the load cell is 0.1285 pm/N and 7.782 N in the conventional measuring range (0-10 kN). Heavy load tension experiments prove that the protection structure works and the sensitivity and resolution are not changed after several high load (65 kN) cycles. In addition, the experiment shows that the resolution of the sensor is 87.79 N in the large load range, allowing the parameter to be used in heavy icing monitoring.

  15. Inductive coupling between overhead power lines and nearby metallic pipelines. A neural network approach

    Directory of Open Access Journals (Sweden)

    Levente Czumbil

    2015-12-01

    Full Text Available The current paper presents an artificial intelligence based technique applied in the investigation of electromagnetic interference problems between high voltage power lines (HVPL and nearby underground metallic pipelines (MP. An artificial neural network (NN solution has been implemented by the authors to evaluate the inductive coupling between HVPL and MP for different constructive geometries of an electromagnetic interference problem considering a multi-layer soil structure. Obtained results are compared to solutions provided by a finite element method (FEM based analysis and considered as reference. The advantage of the proposed method yields in a simplified computation model compared to FEM, and implicitly a lower computational time.

  16. An Insight on Right of Way and its Cost for Power Transmission Cable and Conventional Overhead Transmission Lines

    Science.gov (United States)

    Khandelwal, P.; Pachori, A.; Khandelwal, T.

    2013-12-01

    This paper provides the complete information related to Right of Way (RoW) for the construction of new power transmission line (TL) in terms of present cost for overhead transmission line and underground XLPE transmission cable. The former part of the paper describes the general procedure and rules for acquisition of land for RoW by transmission asset owner (TAO) while in the later part the cost associated to acquire RoW and its impact on the cost of adjacent land have been detailed. It also discusses the actual dismantling cost including the cost of waste metal what TAO get after completion of lifecycle of TL due to increase in metal prices. In this paper cost of RoW after completion of lifecycle of TL is also highlighted. This paper compares the cost of RoW for overhead transmission line and underground XLPE transmission cable for construction of new TL. Also for old transmission infrastructure cost of RoW for change from overhead transmission line to underground XLPE transmission cable is detailed by application of replacement model.

  17. Smart patch integration development of compression connector structural health monitoring in overhead transmission lines

    Science.gov (United States)

    Wang, Hong; Wang, Jy-An J.; Ren, Fei; Chan, John

    2016-04-01

    Integration of smart patches into full-tension splice connectors in overhead power transmission lines was investigated. Lead zirconate titanate (PZT) -5A was used as a smart material and an aluminum beam was used as a host structure. Negative electrode termination was examined by using copper adhesive tape and direct bonding methods. Various commercial adhesives were studied for PZT integration onto the host structure. Aluminum beam specimens with integrated PZT smart patches were tested under thermal cycling at a temperature of 125°C, which is the higher-end temperature experienced by in-service aluminum conductor steel-reinforced cables. Electromechanical impedance (EMI) measurements were conducted at room temperature, and the root mean square deviation (RMSD) of the conductance signals was used to analyze the EMI data. It has been shown that the negative electrode method has an important effect on the performance of the integrated PZT. The PZT displayed more susceptibility to cracking when copper tape was used than when direct bonding was used. The reliability of PZT in direct bonding depended on the adhesives used in bonding layers. Although a hard alumina-based adhesive can lead to cracking of the PZT, a high-temperature epoxy with adequate flexibility, such as Duralco 4538D, can provide the desired performance under target thermal cycling conditions. The RMSD parameter can characterize conductance signatures effectively. It also was demonstrated that RMSD can be used to quantify the fatigue of the PZT integration system, although RMSD is used primarily as a damage index in monitoring structural health.

  18. Increased range of ultrasonic guided wave testing of overhead transmission line cables using dispersion compensation.

    Science.gov (United States)

    Legg, Mathew; Yücel, Mehmet K; Kappatos, Vassilios; Selcuk, Cem; Gan, Tat-Hean

    2015-09-01

    Overhead Transmission Line (OVTL) cables can experience structural defects and are, therefore, inspected using Non-Destructive Testing (NDT) techniques. Ultrasonic Guided Waves (UGW) is one NDT technique that has been investigated for inspection of these cables. For practical use, it is desirable to be able to inspect as long a section of cable as possible from a single location. This paper investigates increasing the UGW inspection range on Aluminium Conductor Steel Reinforced (ACSR) cables by compensating for dispersion using dispersion curve data. For ACSR cables, it was considered to be difficult to obtain accurate dispersion curves using modelling due to the complex geometry and unknown coupling between wire strands. Group velocity dispersion curves were, therefore, measured experimentally on an untensioned, 26.5m long cable and a method of calculating theoretical dispersion curves was obtained. Attenuation and dispersion compensation were then performed for a broadband Maximum Length Sequence (MLS) excitation signal. An increase in the Signal to Noise Ratio (SNR) of about 4-8dB compared to that of the dispersed signal was obtained. However, the main benefit was the increased ability to resolve the individual echoes from the end of the cable and an introduced defect in the form of a cut, which was 7 to at least 13dB greater than that of the dispersed signal. Five echoes were able to be clearly detected using MLS excitation signal, indicating the potential for an inspection range of up to 130m in each direction. To the best of the authors knowledge, this is the longest inspection range for ACSR cables reported in the literature, where typically cables, which were only one or two meter long, have been investigated previously. Narrow band tone burst and Hann windowed tone burst excitation signal also showed increased SNR and ability to resolve closely spaced echoes. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Smart patch integration development of compression connector structural health monitoring in overhead transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hong [ORNL; Wang, Jy-An John [ORNL; Ren, Fei [ORNL; Chan, John [Electric Power Research Institute (EPRI)

    2016-01-01

    Integration of smart patches into full-tension splice connectors in overhead power transmission lines was investigated. Lead zirconate titanate (PZT) -5A was used as a smart material and an aluminum beam was used as a host structure. Negative electrode termination was examined by using copper adhesive tape and direct bonding methods. Various commercial adhesives were studied for PZT integration onto the host structure. Aluminum beam specimens with integrated PZT smart patches were tested under thermal cycling at a temperature of 125 C, which is the higher-end temperature experienced by in-service aluminum conductor steel-reinforced cables. Electromechanical impedance (EMI) measurements were conducted at room temperature, and the root mean square deviation (RMSD) of the conductance signals was used to analyze the EMI data. It has been shown that the negative electrode method has an important effect on the performance of the integrated PZT. The PZT displayed more susceptibility to cracking when copper tape was used than when direct bonding was used. The reliability of PZT in direct bonding depended on the adhesives used in bonding layers. Although a hard alumina based adhesive can lead to cracking of the PZT, a high-temperature epoxy with adequate flexibility, such as Duralco 4538D, can provide the desired performance under target thermal cycling conditions. The RMSD parameter can characterize conductance signatures effectively. It also was demonstrated that RMSD can be used to quantify the fatigue of the PZT integration system, although RMSD is used primarily as a damage index in monitoring structural health.

  20. Operation and Maintenance of Overhead Transmission Line%架空输电线路的运行维护

    Institute of Scientific and Technical Information of China (English)

    王刚

    2014-01-01

    架空输电线路是将不同地区的发电厂、变电站、负荷点连接起来,起输送或交换电能作用的线路。由于架空线路暴露在大气环境中,易受到雷电袭击、雨淋、湿雾以及自然和工业污秽等造成停电事故。因此,加强架空输电线路的运行维护具有重要的意义。%Overhead transmission line is connecting the power plant, transformer substation, load point in different regions, designed for conveyance or exchange of electric energy. Bec- ause the overhead line is exposed to the atmosphere, it is often caused blackouts due to lightning, rain, wet fog and natural and industrial polution. Therefore, it is of important significa- nce to strengthen the maintenance operation of overhead tran- smission lines.

  1. U.K. linesmen's experience of microshocks on HV overhead lines.

    Science.gov (United States)

    Ahmed, Y; Rowland, S M

    2009-08-01

    Linesmen working on high voltage equipment occasionally report unpleasant discharges from equipment. The sensation is known as microshocks, which result from capacitive coupling of the linesmen to high voltage sources and subsequent discharging when in very close proximity to grounded objects. Often, this is just an annoyance, but the levels can become such that work has to cease. Microshocks are unpredictable, and therefore, planning maintenance work around them has not been possible. A survey has been developed to investigate and quantify different factors that may have a direct influence on the frequency and intensity of discharges. Transmission line workers (N = 102) from England and Wales participated in the survey and provided details of personal body characteristics as well as their experiences of microshocks. Survey results suggest a correlation between body mass index and certain work activities to the likelihood of a person experiencing microshocks, and their severity. Higher body mass index reduces the likelihood of experiencing painful microshocks. Climbing lattice towers adjacent to energized conductors is the area most associated with the phenomenon. Microshock incidents have increased or are occurring at the same rate as 5 years ago. Results presented will aid the development of policy statements and mitigation techniques that minimize linesmen's exposure to microshocks. [Supplementary materials are available for this article. Go to the publisher's online edition of the Journal of Occupational and Environmental Hygiene for the following free supplemental resources: a PDF file containing survey questions.].

  2. Living and Working Safely Around High-Voltage Power Lines.

    Energy Technology Data Exchange (ETDEWEB)

    United States. Bonneville Power Administration.

    2001-06-01

    High-voltage transmission lines can be just as safe as the electrical wiring in the homes--or just as dangerous. The crucial factor is ourselves: they must learn to behave safely around them. This booklet is a basic safety guide for those who live and work around power lines. It deals primarily with nuisance shocks due to induced voltages, and with potential electric shock hazards from contact with high-voltage lines. References on possible long-term biological effects of transmission lines are shown. In preparing this booklet, the Bonneville Power Administration has drawn on more than 50 years of experience with high-voltage transmission. BPA operates one of the world`s largest networks of long-distance, high-voltage lines. This system has more than 400 substations and about 15,000 miles of transmission lines, almost 4,400 miles of which are operated at 500,000 volts.

  3. The Way of Reducing Current Values in Optical Ground Wires at Asymmetrical Faults on Overhead Transmission Lines

    Directory of Open Access Journals (Sweden)

    Egamnazarov Georgiy

    2016-12-01

    Full Text Available Given the fact that the installing costs of an optical ground wire on overhead lines directly depend on its cross-section, which in turn depends on the level of fault current it should withstand, in order to reduce these current values in the optical ground wire, I suggested performing its isolated descents from the end towers of the line with its transition to an optical cable. The research was carried out on the example of a 500 kV overhead line in the National Electric Power Grid. The Method of Symmetrical Components for calculating asymmetrical fault currents was not used; therefore, calculations were carried out on the base of presenting the line as a multi-wire system for the considered case as a five-wire system (optical ground wire, steel ground wire, and three phase wires. Such approach allows taking into account the initial asymmetry of the line parameters and modeling any kind of asymmetrical faults. The analyses of calculated results were performed. The conclusive evidence that the optical ground wire isolated descents from the end towers of the line give the possibility of reducing the level of maximal fault current distribution values in it and therefore its cross section, is presented.

  4. On-Line Voltage Stability Assessment based on PMU Measurements

    DEFF Research Database (Denmark)

    Garcia-Valle, Rodrigo; P. Da Silva, Luiz C.; Nielsen, Arne Hejde

    2009-01-01

    through statistic analysis. During the off-line analysis, a memory of high-risk situations following a pre-defined voltage stability criterion is obtained. Thereafter, basic statistics analyses are applied resulting in the definition of voltage regions. During on-line operation, voltage magnitudes......This paper presents a method for on-line monitoring of risk voltage collapse based on synchronised phasor measurement. As there is no room for intensive computation and analysis in real-time, the method is based on the combination of off-line computation and on-line monitoring, which are correlated...... of critical buses obtained by phasor measurements are monitored in relation to the risk regions. Comprehensive studies demonstrate that the proposed method could assist operators to avoid voltage collapse events, by taking preventive or emergency actions....

  5. The influence of lightning induced voltage on the distribution power line polymer insulators

    Science.gov (United States)

    Ab-Kadir, Mohd Zainal Abidin; Gomes, Chandima; Jasni, Jasronita; Hajikhani, Maryam

    2017-01-01

    Protection of medium voltage (MV) overhead lines against the indirect effects of lightning is an important issue in Malaysia and other tropical countries. Protection of these lines against the indirect effects of lightning is a major concern and can be improved by several ways. The choice of insulator to be used for instance, between the glass, ceramic or polymer, can help to improve the line performance from the perspective of increasing the breakdown strength. In this paper, the electrical performance of a 10 kV polymer insulator under different conditions for impulse, weather and insulator angle with respect to a cross-arm were studied (both experimental and modelling) and the results were discussed accordingly. Results show that the weather and insulator angle (with respect to the cross-arm) are surprisingly influenced the values of breakdown voltage and leakage current for both negative and positive impulses. Therefore, in order to select a proper protection system for MV lines against lightning induced voltage, consideration of the local information concerning the weather and also the insulator angles with respect to the cross-arm are very useful for line stability and performance. PMID:28234930

  6. The influence of lightning induced voltage on the distribution power line polymer insulators.

    Science.gov (United States)

    Izadi, Mahdi; Abd Rahman, Muhammad Syahmi; Ab-Kadir, Mohd Zainal Abidin; Gomes, Chandima; Jasni, Jasronita; Hajikhani, Maryam

    2017-01-01

    Protection of medium voltage (MV) overhead lines against the indirect effects of lightning is an important issue in Malaysia and other tropical countries. Protection of these lines against the indirect effects of lightning is a major concern and can be improved by several ways. The choice of insulator to be used for instance, between the glass, ceramic or polymer, can help to improve the line performance from the perspective of increasing the breakdown strength. In this paper, the electrical performance of a 10 kV polymer insulator under different conditions for impulse, weather and insulator angle with respect to a cross-arm were studied (both experimental and modelling) and the results were discussed accordingly. Results show that the weather and insulator angle (with respect to the cross-arm) are surprisingly influenced the values of breakdown voltage and leakage current for both negative and positive impulses. Therefore, in order to select a proper protection system for MV lines against lightning induced voltage, consideration of the local information concerning the weather and also the insulator angles with respect to the cross-arm are very useful for line stability and performance.

  7. Transmission Line Ampacity Improvements of AltaLink Wind Plant Overhead Tie-Lines Using Weather-Based Dynamic Line Rating

    Energy Technology Data Exchange (ETDEWEB)

    Bhattarai, Bishnu P.; Gentle, Jake P.; Hill, Porter; McJunkin, Tim; Myers, Kurt S.; Abbound, Alex; Renwick, Rodger; Hengst, David

    2017-07-01

    Abstract—Overhead transmission lines (TLs) are conventionally given seasonal ratings based on conservative environmental assumptions. Such an approach often results in underutilization of the line ampacity as the worst conditions prevail only for a short period over a year/season. We presents dynamic line rating (DLR) as an enabling smart grid technology that adaptively computes ratings of TLs based on local weather conditions to utilize additional headroom of existing lines. In particular, general line ampacity state solver utilizes measured weather data for computing the real-time thermal rating of the TLs. The performance of the presented method is demonstrated from a field study of DLR technology implementation on four TL segments at AltaLink, Canada. The performance is evaluated and quantified by comparing the existing static and proposed dynamic line ratings, and the potential benefits of DLR for enhanced transmission assets utilization. For the given line segments, the proposed DLR results in real-time ratings above the seasonal static ratings for most of the time; up to 95.1% of the time, with a mean increase of 72% over static rating.

  8. Determination of Steady-State and Faulty Regimes of Overhead Lines by Means of Multiconductor Cell Analysis (MCA

    Directory of Open Access Journals (Sweden)

    Fabio Guglielmi

    2012-07-01

    Full Text Available Single-phase positive sequence modelling is often used in power systems when power flows and short circuit analysis are assessed. Of course, the use of single-phase positive sequence modelling assumes purely three-phase configurations and perfectly symmetrical ones so that single-phase modelling considers that all the phase conductors behave in the same way. When considering the physical reality of power networks, this assumption can be questionable and the behaviors of all the system conductors including the passive ones (earth wires for overhead lines, metallic screens and armours for cables and enclosures for gas insulated lines is completely unknown. Therefore, the present multiconductor cell analysis (MCA becomes necessary, since it allows one to achieve great precision results on the regimes of both phase conductors and passive conductors. MCA offers a powerful tool in order to validate (or less approximated and simplified computation methods. In particular, for single and double circuit overhead lines (OHLs, the current phasors induced in the earth wires and the ground return current alongside the line can be directly computed by MCA in steady state and faulty regimes. It is worth noting that, for faulty regimes, MCA allows also evaluating the approximation degree and validity field of screening factors k.

  9. 3D Power Line Reconstruction from Airborne LiDAR Point Cloud of Overhead Electric Power Transmission Corridors

    Directory of Open Access Journals (Sweden)

    LIN Xiangguo

    2016-03-01

    Full Text Available 3D power line reconstruction is one of the main tasks in power line patrols using LiDAR systems mounted on helicopters. A 3D reconstruction method is proposed to reconstruct the power lines from the airborne LiDAR point clouds of the overhead electric power transmission corridors. Firstly, the pylons' LiDAR points and the initial routine trajectory of the transmission lines are employed to derive the precise information such as the locations and number of the pylons, the real routine trajectory, and the total number of spans. Secondly, the power line corridor is divided into a number of spans, the scope of each span in the XOY plane is determined, and the powerline LiDAR points are allocated into the corresponding spans where they are located. Thirdly, the powerline points of each span are clustered by the k-means algorithm in a normalized projection space, and each cluster corresponds to one power line. Finally, each power line is reconstructed based on a combination of a line model and a parabola model. Two experiments suggest that the proposed method is capable of automatically and correctly reconstructing 3D models of the long power lines with high accuracy. Moreover, it is robust to many factors such as the changing number, types, arrangements, blunders of the power lines, the changing length of the spans, and the irregular breakage of the LiDAR point clouds.

  10. Comparison between IEEE and CIGRE Thermal Behaviour Standards and Measured Temperature on a 132-kV Overhead Power Line

    Directory of Open Access Journals (Sweden)

    Alberto Arroyo

    2015-12-01

    Full Text Available This paper presents the steady and dynamic thermal balances of an overhead power line proposed by CIGRE (Technical Brochure 601, 2014 and IEEE (Std.738, 2012 standards. The estimated temperatures calculated by the standards are compared with the averaged conductor temperature obtained every 8 min during a year. The conductor is a LA 280 Hawk type, used in a 132-kV overhead line. The steady and dynamic state comparison shows that the number of cases with deviations to conductor temperatures higher than 5 ∘ C decreases from around 20% to 15% when the dynamic analysis is used. As some of the most critical variables are magnitude and direction of the wind speed, ambient temperature and solar radiation, their influence on the conductor temperature is studied. Both standards give similar results with slight differences due to the different way to calculate the solar radiation and convection. Considering the wind, both standards provide better results for the estimated conductor temperature as the wind speed increases and the angle with the line is closer to 90 ∘ . In addition, if the theoretical radiation is replaced by that measured with the pyranometer, the number of samples with deviations higher than 5 ∘ C is reduced from around 15% to 5%.

  11. Estimation of line flows and bus voltages using decision trees

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.C.; Hsu, Y.Y. (National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Electrical Engineering)

    1994-08-01

    A machine learning method called the ID3 (Interative Dichotomizer 3) approach is presented for the estimation of line flows and bus voltages following an outage event. A decision tree which is capable of generating the desired line flows and bus voltages are created using the training patterns which are compiled from the historical operating records of Taiwan power system. The established decision tree contains the knowledge which is essential for line flow and bus voltage prediction. Thus, it can be applied to estimate line flows and bus voltages of a system in an efficient manner. The effectiveness of the proposed ID3 approach is demonstrated by security assessment of Taiwan power system which contains 170 buses and 207 lines.

  12. Discrete-event simulation of the shielding failure of the arrester protected overhead-lines to evaluate risk of flashover

    Energy Technology Data Exchange (ETDEWEB)

    Bank Tavakoli, M.R.; Vahidi, B.; Hosseinian, S.H. [Department of Electrical Engineering, Amirkabir University of Technology, Hafez Avenue, No. 424, P.O. Box 15875-4413, Tehran (Iran)

    2008-12-15

    Damages caused by lightning stroke in power system networks are severe for insulations and result in less reliable energy supply. Knowledge of protection schemes and better selection of these devices in power systems is a goal of designers to reduce the risk of flashover in any risky point. In this paper, a statistical procedure is presented to evaluate risk of failure in an overhead-line which is protected by arresters in most risky towers. Main aim of the work is to present the modeling aspects for considering random nature of stroke and its simulation procedure. The random nature of a lightning stroke composed of proper discrete-event simulation of a stroke via its peak current, front time and tail time and accurate mathematical representation of such lightning stroke in a transient analyzer. In addition, the maximum lightning current which causes shielding failure for a specified tower design and probabilistic specification of lightning for discrete-event simulation is taken into account. As a study case, random nature modeled lightning strokes are applied to a 230 kV overhead-line which is located in a hilly area and the risk of failure is calculated when arresters are located beside the stroke point. (author)

  13. Single-phase AutoReClosure ARC failure on 400 kV combinedcable/overhead line with permanently connected shunt reactor

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Søgaard, Kim

    2008-01-01

    consisting of overhead lines, crossbonded cable sections and shunt reactor has been created in PSCAD/EMTDC and verified against measurements with good results. Main focus has been put on the likelihood of having a successful single-phase autoreclosure ARC in such a combined cable/OHL line....

  14. Overhead Utility Lines at Cedar Breaks National Monument, Utah (cebr_powerln)

    Data.gov (United States)

    National Park Service, Department of the Interior — This coverage contains 49 arcs and 50 nodes representing power lines at Cedar Breaks National Monument. The power lines supply electricity and telephone services to...

  15. Usage and Benefit of an Overhead Line Monitoring System%架空线路监测系统的使用和效益

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Overhead lines are the backbone of the electrical power transmission. Contrary to the distributions networks, the transmission system consists only in exceptional cases of longer cable lines. Typical exceptions are connections of cavern power plants, approaches to airports or bird sanctuaries and lines in urban centres. In the majority of cases, an overhead line is the most economic and practicable solution for the energy transmission. In tourism regions, an overhead line will be seen as impairment of nature or landscape and so the approval chain and procedure is in most countries long-winded and circumstantial. At the other hand, the energy consumption in Europe is growing and the volatility of transmitted power is also increasing during the last decade caused by the opening of the electric energy market. This opening process leads to a stopping of the enlargement of the interoperation network and to a minimisation of the maintenance of existing lines. Today the network operates more often at the limit of the equipment and the small and large-areas disturbances and blackouts are increasing. The operators of transmission lines are forced to ensure the electrical power supply and so they have to improve the reliability of the network. One solution is to monitor the critical (heavy loaded) overhead lines. For example, with the knowledge of the thermal condition, the risk of unexpected outages can be reduced.Today several monitoring systems are available on the market. They differ in the principle and techniques of the condition evaluation. The three most interesting output variables are the line temperature, the capable transmission power and the actual sag of the investigated section. In this paper an overview of existing overhead line monitoring system and also an outline over the usage and benefit for the application will be given. Thermal monitoring is one technique to improve the reliability of the network and for increasing or optimising the capable

  16. Electronic Current Transducer (ECT) for high voltage dc lines

    Science.gov (United States)

    Houston, J. M.; Peters, P. H., Jr.; Summerayes, H. R., Jr.; Carlson, G. J.; Itani, A. M.

    1980-02-01

    The development of a bipolar electronic current transducer (ECT) for measuring the current in a high voltage dc (HVDC) power line at line potential is discussed. The design and construction of a free standing ECT for use on a 400 kV line having a nominal line current of 2000 A is described. Line current is measured by a 0.0001 ohm shunt whose voltage output is sampled by a 14 bit digital data link. The high voltage interface between line and ground is traversed by optical fibers which carry digital light signals as far as 300 m to a control room where the digital signal is converted back to an analog representation of the shunt voltage. Two redundant electronic and optical data links are used in the prototype. Power to operate digital and optical electronics and temperature controlling heaters at the line is supplied by a resistively and capacitively graded 10 stage cascade of ferrite core transformers located inside the hollow, SF6 filled, porcelain support insulator. The cascade is driven by a silicon controlled rectifier inverter which supplies about 100 W of power at 30 kHz.

  17. Assessment of electromagnetic field levels from surrounding high-tension overhead power lines for proposed land use.

    Science.gov (United States)

    Al-Bassam, E; Elumalai, A; Khan, A; Al-Awadi, L

    2016-05-01

    The surrounding outdoor environment for new development has a big effect on the indoor quality of life. The main aim of this work was to determine the suitability of the area for building new schools with reference to electromagnetic field (EMF) effects. The specific objective of this study was to detect the safe distance from the EMF posed by the high-tension overhead power lines in the vicinity of the specified area. The measurements were taken for both the electric and magnetic fields in different months in order to detect the highest EMF levels during the peak power load season. EMDEX II with E-probe and EMDEX II with Linda were used for the measurements. These instruments were all calibrated by ENERTECH Company in USA. The EMF associated with high tension transmission lines that surrounded the proposed site has to be below 0.2 μT (Italian EMF regulations are the most suitable regulations for the establishment of schools in Kuwait). The safety clearance distance from the existing 300-kV high-tension power line has been assigned as 200 m and from other existing 132-kV high-tension power line was 50 m. The proposed site with its predefined boundaries has a magnetic field below the Italian EMF regulations for the establishment of new schools.

  18. The Time-Varying Characteristics of Overhead Electric Transmission Lines Considering the Induced-Ice-Shedding Effect

    Directory of Open Access Journals (Sweden)

    Kunpeng Ji

    2015-01-01

    Full Text Available More ice deposits accreted on conductors or ground wires may be shed off when an overhead electric transmission line is responding to shocks initiated by natural ice shedding. Ice shedding causes the global mass, stiffness, and damping of the tower-line system to vary with time, and the successive shedding effect beyond a trigger event has not been taken into account in previous studies due to the lack of an adequate ice detachment model. In this paper, the ice shedding effect induced by initial shocks was considered in finite element (FE analysis. An ice detachment criterion, in the way of user-defined element rupture subroutine, was implemented into the main commercial nonlinear FE program ADINA, making it possible to consider the induced-ice-shedding effect numerically. The incremental FE form of the system’s governing equations of motion is presented where the variations in the mass and stiffness matrices of the system are taken into consideration. Taking a transmission line section following natural ice shedding as a case study, the results indicate that neglecting successive ice shedding underestimates the adverse influence of natural ice shedding. The proposed method can help to improve the design and evaluation of transmission lines in cold regions and to ensure their mechanical security.

  19. Ice shedding from overhead electrical lines by mechanical breaking : a ductile model for viscoplastic behaviour of atmospheric ice

    Energy Technology Data Exchange (ETDEWEB)

    Eskandarian, M.

    2005-07-01

    The mechanical characteristics of power line components need improvement in order to avoid power failures during severe ice storms. Atmospheric icing of overhead power lines creates electrical and mechanical problems in the transmission network. The successful development of anti-icing and de-icing techniques requires good knowledge of the adherence and bulk strength characteristics of atmospheric ice. This study presented a model for viscoplastic behaviour of porous atmospheric ice in the ductile region. The model was then modified to consider the effects of cracking activities to predict the material behaviour in transition and brittle regions. The following general methodologies were followed in this research for describing the ductile behaviour of porous atmospheric ice: instantaneous elastic strain; delayed viscoelastic strain; and, permanent plastic strain. The scientific contributions of this study include a classification of atmospheric ice structure on power lines on the basis of its grain shape and c-axis orientation. This thesis also presented 3 computer codes in Maple Mathematical Program for determining the elastic moduli of various types of freshwater ice; a poroelastic model for modifying the elastic moduli of porous atmospheric ice; a cap-model plasticity for various types of porous atmospheric ice; new freshwater ice yield envelopes in ductile regions that take porosity into account by means of an elliptical moving cap; and a newly developed user-defined material subroutine for viscoplastic behaviour of atmospheric ice in ductile region including the poroelastic, viscoelastic, and cap-model plasticity.

  20. Single-phase AutoReClosure ARC failure on 400 kV combinedcable/overhead line with permanently connected shunt reactor

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Søgaard, Kim

    2008-01-01

    This paper demonstrates the results from a detailed study of the dynamic behavior of a shunt reactor compensated 400 kV combined cable/overhead line. This is accomplished by means of theoretical considerations, simulations and measurements. The work presented here is based on a real-life operating...

  1. Simulation of the interaction between overhead contact line and pantographs with the finite element method; Simulation des Systems Oberleitungskettenwerk und Stromabnehmer mit der Finite-Elemente-Methode

    Energy Technology Data Exchange (ETDEWEB)

    Reichmann T. [Siemens AG, Erlangen (Germany). Transportation Systems

    2005-02-01

    When developing overhead contact line systems and assessing their conformity simulation of the interaction with pantographs is not anymore dispensable today. The tools used for simulation must model flexibly and precisely all parameters of the contact line and deliver findings, which correspond reliably to measurements of the current collection quality. Simulations adopting the finite element method comply with these requirements and, due to the high capacity of computers available today, can be used advantageously to study the interaction and other features. (orig.)

  2. 30 CFR 75.705-2 - Repairs to energized surface high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized surface high-voltage lines... Repairs to energized surface high-voltage lines. An energized high-voltage surface line may be repaired... on power circuits with a phase-to-phase nominal voltage no greater than 15,000 volts; (3)...

  3. Secure and Time-Aware Communication of Wireless Sensors Monitoring Overhead Transmission Lines.

    Science.gov (United States)

    Mazur, Katarzyna; Wydra, Michal; Ksiezopolski, Bogdan

    2017-07-11

    Existing transmission power grids suffer from high maintenance costs and scalability issues along with a lack of effective and secure system monitoring. To address these problems, we propose to use Wireless Sensor Networks (WSNs) as a technology to achieve energy efficient, reliable, and low-cost remote monitoring of transmission grids. With WSNs, smart grid enables both utilities and customers to monitor, predict and manage energy usage effectively and react to possible power grid disturbances in a timely manner. However, the increased application of WSNs also introduces new security challenges, especially related to privacy, connectivity, and security management, repeatedly causing unpredicted expenditures. Monitoring the status of the power system, a large amount of sensors generates massive amount of sensitive data. In order to build an effective Wireless Sensor Network (WSN) for a smart grid, we focus on designing a methodology of efficient and secure delivery of the data measured on transmission lines. We perform a set of simulations, in which we examine different routing algorithms, security mechanisms and WSN deployments in order to select the parameters that will not affect the delivery time but fulfill their role and ensure security at the same time. Furthermore, we analyze the optimal placement of direct wireless links, aiming at minimizing time delays, balancing network performance and decreasing deployment costs.

  4. Secure and Time-Aware Communication of Wireless Sensors Monitoring Overhead Transmission Lines

    Directory of Open Access Journals (Sweden)

    Katarzyna Mazur

    2017-07-01

    Full Text Available Existing transmission power grids suffer from high maintenance costs and scalability issues along with a lack of effective and secure system monitoring. To address these problems, we propose to use Wireless Sensor Networks (WSNs as a technology to achieve energy efficient, reliable, and low-cost remote monitoring of transmission grids. With WSNs, smart grid enables both utilities and customers to monitor, predict and manage energy usage effectively and react to possible power grid disturbances in a timely manner. However, the increased application of WSNs also introduces new security challenges, especially related to privacy, connectivity, and security management, repeatedly causing unpredicted expenditures. Monitoring the status of the power system, a large amount of sensors generates massive amount of sensitive data. In order to build an effective Wireless Sensor Network (WSN for a smart grid, we focus on designing a methodology of efficient and secure delivery of the data measured on transmission lines. We perform a set of simulations, in which we examine different routing algorithms, security mechanisms and WSN deployments in order to select the parameters that will not affect the delivery time but fulfill their role and ensure security at the same time. Furthermore, we analyze the optimal placement of direct wireless links, aiming at minimizing time delays, balancing network performance and decreasing deployment costs.

  5. Eliminating harmonics in line to line voltage using genetic algorithm using multilevel inverter

    Energy Technology Data Exchange (ETDEWEB)

    Gunasekaran, R. [Excel College of Engineering and Technology, Komarapalayam (India). Electrical and Electronics Engineering; Karthikeyan, C. [K.S. Rangasamy College of Engineering, Tamil Nadu (India). Electrical and Electronics Engineering

    2017-04-15

    In this project the total harmonic distortion (THD) minimization of the multilevel inverters output voltage is discussed. The approach in reducing harmonics contents in inverters output voltage is THD elimination. The switching angles are varied with the fundamental frequency so the output THD is minimized. In three phase applications, the line voltage harmonics are of the main concern from the load point of view. Using a genetic algorithm, a THD minimization process is directly applied to the line to line voltage of the inverter. Genetic (GA) algorithm allows the determination of the optimized parameters and consequently an optimal operating point of the circuit and a wide pass band with a unity gain is obtained.

  6. An Annotated Bibliography of High-Voltage Direct-Current Transmission and Flexible AC Transmission (FACTS) Devices, 1991-1993.

    Energy Technology Data Exchange (ETDEWEB)

    Litzenberger, Wayne; Lava, Val

    1994-08-01

    References are contained for HVDC systems, converter stations and components, overhead transmission lines, cable transmission, system design and operations, simulation of high voltage direct current systems, high-voltage direct current installations, and flexible AC transmission system (FACTS).

  7. Technology of Disaster Prevention and Reduction of Overhead Power Lines%架空配电线路防灾减灾技术研究

    Institute of Scientific and Technical Information of China (English)

    林土方; 许家益; 沈淼

    2016-01-01

    Overhead power lines affected by extreme weather disasters like typhoon , tornado and ice storm may have wire break , tower bend or even fall off , causing power line trip , affecting the normal power sup-ply .Power recovery is influenced by the tower transportation , construction and other core elements , how to effectively reduce the influence of disasters on overhead distribution lines , narrow the scope of the power outage caused by disasters and reduce the outage time is the focus of social attention .This paper mainly discusses the technical measures to prevent and reduce the damage for the overhead distribution lines .%架空配电线路受台风、龙卷风、冰灾等极端天气灾害影响,会发生导线断线、杆塔弯曲甚至倒断,引起线路跳闸停电,影响社会正常供电。抢修恢复受杆塔运输、施工等核心要素制约,如何有效降低架空配电线路受灾害的影响,缩小灾害引发的停电范围,减少停电时间,是社会关注的热点。文章重点探讨防范并减少架空配电线路受灾的技术措施。

  8. 30 CFR 77.704-2 - Repairs to energized high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized high-voltage lines. 77.704... UNDERGROUND COAL MINES Grounding § 77.704-2 Repairs to energized high-voltage lines. An energized high-voltage... repairs will be performed on power circuits with a phase-to-phase nominal voltage no greater than...

  9. 30 CFR 77.704-1 - Work on high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines. 77.704-1 Section 77... MINES Grounding § 77.704-1 Work on high-voltage lines. (a) No high-voltage line shall be regarded as... provided in § 77.103) that such high-voltage line has been deenergized and grounded. Such qualified...

  10. 30 CFR 75.705-1 - Work on high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines. 75.705-1 Section 75... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-1 Work on high-voltage lines. (a) Section 75.705 specifically prohibits work on energized high-voltage lines underground;...

  11. Childhood cancer and magnetic fields from high-voltage power lines in England and Wales: a case–control study

    Science.gov (United States)

    Kroll, M E; Swanson, J; Vincent, T J; Draper, G J

    2010-01-01

    Background: Epidemiological evidence suggests that chronic low-intensity extremely-low-frequency magnetic-field exposure is associated with increased risk of childhood leukaemia; it is not certain the association is causal. Methods: We report a national case–control study relating childhood cancer risk to the average magnetic field from high-voltage overhead power lines at the child's home address at birth during the year of birth, estimated using National Grid records. From the National Registry of Childhood Tumours, we obtained records of 28 968 children born in England and Wales during 1962–1995 and diagnosed in Britain under age 15. We selected controls from birth registers, matching individually by sex, period of birth, and birth registration district. No participation by cases or controls was required. Results: The estimated relative risk for each 0.2 μT increase in magnetic field was 1.14 (95% confidence interval 0.57 to 2.32) for leukaemia, 0.80 (0.43–1.51) for CNS/brain tumours, and 1.34 (0.84–2.15) for other cancers. Conclusion: Although not statistically significant, the estimate for childhood leukaemia resembles results of comparable studies. Assuming causality, the estimated attributable risk is below one case per year. Magnetic-field exposure during the year of birth is unlikely to be the whole cause of the association with distance from overhead power lines that we previously reported. PMID:20877338

  12. 30 CFR 77.807-3 - Movement of equipment; minimum distance from high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... high-voltage lines. 77.807-3 Section 77.807-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-3 Movement of equipment; minimum distance from high-voltage lines. When any part of any equipment operated on the surface of...

  13. 30 CFR 56.12071 - Movement or operation of equipment near high-voltage power lines.

    Science.gov (United States)

    2010-07-01

    ...-voltage power lines. 56.12071 Section 56.12071 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... NONMETAL MINES Electricity § 56.12071 Movement or operation of equipment near high-voltage power lines. When equipment must be moved or operated near energized high-voltage powerlines (other than...

  14. 30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ...-voltage lines. 77.807-2 Section 77.807-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-2 Booms and masts; minimum distance from high-voltage lines. The booms and masts of equipment operated on the surface of...

  15. Thermometer by optical fiber for ampacity studies in overhead transmission lines; Termometro a fibra optica para estudo da ampacidade em linhas de transmissao aereas

    Energy Technology Data Exchange (ETDEWEB)

    Valente, L.C.G.; Kawase, L.R.; Silva Filho, J.I. da; Silva, J.M.M. da [Centro de Pesquisas de Energia Eletrica, Rio de Janeiro, RJ (Brazil); Igarashi, A.Y. [Universidade Federal, Rio de Janeiro, RJ (Brazil)

    1995-12-31

    This article suggests the utilization of thermometers constructed from optical fibers technology in overhead power transmission lines. This will help the studies in progress about the electric power systems ampacity. It also presents the advantages of using optical fibers instead of conventional thermometers. As an example, the fact that the optical fibers are dielectric and make possible the remote monitoring. It is also shown a possibility of introducing such measuring system in electric junctions where OPGW cables are used 4 refs., 4 figs.; e-mail: liliana at fis.puc-rio.br

  16. A Reading of the Technical Supervision Guideline for Overhead Transmission Lines%架空输电线路技术监督导则解读

    Institute of Scientific and Technical Information of China (English)

    刘洋; 郭跃男; 柳贡强; 兰森; 郭红旭

    2016-01-01

    National power grid (2005) No. 174 “Technical supervision regulations for 110 (66) kV~ 500 kV overhead transmission lines” is the guiding document for the professional technical supervision of the transmission lines, which plays an active role in the secure, stable and reliable operation of the power network. However, with the rapid development of power grid and the demand of the lean management of transmission lines, the technical supervision is given a new meaning. With strengthening the technical supervision work of transmission lines as the guiding ideology, based on the professional and technical supervision, and with the overhead transmission lines as the object, and according to the national, industry and state grid corporation’s enterprise standards, regulations and system, applications of new technology, new equipment and new materials are fully considered and new contents are appropriately increased.To meet the requirements of power grid development as the basic goal, and from the aspects of feasibility study, engineering design, equipment purchasing and manufacturing, equipment acceptance, transportation and storage, installation and testing, completion acceptance, operation maintenance and overhaul and retiring and scrapping of overhead transmission lines, the technical guideline for supervising overhead transmission lines is thoroughly read, through which the safe, reliable and economic operation of overhead transmission lines is guaranteed.%原国家电网生技〔2005〕174号文《110(66) kV~500 kV架空输电线路技术监督规定》是线路专业技术监督工作指导性文件,对电网安全、稳定、可靠运行起到了积极的指导作用。但随着电网的快速发展和输电专业精益化管理的需求,技术监督工作被赋予新的内涵。以加强架空输电线路技术监督工作为指导思想,在专业技术监督基础上,以架空输电线路为对象,依据国家、行业及国家电网公司企业

  17. Calculations of lightning-induced voltages in medium voltage distribution lines

    Energy Technology Data Exchange (ETDEWEB)

    Munhoz Rojas, Patricio E. [Instituto de Tecnologia para o Desenvolvimento (LACTEC/UFPR), Curitiba, PR (Brazil)], E-mail: patricio@lactec.org.br; Pinto, Cleverson Luiz da Silva [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil)], E-mail: cleverson@copel.com

    2007-07-01

    The objective of this paper is to show the results of a new computer program, written in Mat Lab environment, that is intended to calculate the lightning induced voltages in multi-conductor non-homogeneous lines, in order to be able to evaluate the impact of the usual protective measures implemented against lightning-induced disturbances. The main new features of this program are: a coupling model in terms of the scalar potentials referred to a remote ground was adopted; the coupling to the vertical conductors was considered in a manner similar to rest of the line; the describing equations were converted into a system of coupled ordinary differential equations, by a discretization only in space, which was subsequently solved using the powerful ODE solvers existing in Mat Lab. The validation of the new program has been performed by comparing its predicted results with other theoretical and computational results available in the literature and also with other experimental results published in the literature. It is shown that the agreement with other well established theoretical results is very good and, also, that the agreement between the newly calculated results and some published experimental results is better than previously obtained results. (author)

  18. The Deep Application of the State Management over the Overhead Transmission Line%架空输电线路状态管理的深化应用

    Institute of Scientific and Technical Information of China (English)

    娄小明

    2013-01-01

    In recent years,with the development of the economy,there are great changes in the west-east power transmission construction, the geographic conditions of the overhead line working. There are many problems in the line operation-maintenance. In this article,the author analyzed the maintenance situation of overhead line facility in his company. Combining the management requirement of the state of the electric transmission line,he classified the daily operations into 9 aspects,such as preventing the damage caused by thunder,bird strike,damage caused by wind,icing,pollution,forest fire,flood and debris flow,external damage,and the contradiction of the tree and line. And then,the author came up with some corresponding measures based on his experience and the present technology. The PDAC cycling management was carried out during the one year practice,and the manage level over the overhead transmission line has been improved obviously.%近年,随着社会经济的发展,西电东送的建设,架空线路的运行环境发生了巨大的变化,线路运检面临许多新的困难,面对新形势,通过对笔者所在单位所辖线路运维情况的分析,结合输电线路的状态管理要求将线路的运维工作分为防治雷害、鸟害、风害、覆冰、污秽、山火、洪水泥石流、外力破坏、线树矛盾,根据运维经验和现阶段技术方法提出相应治理措施,实行PDCA循环管理,经过一年多的实践,架空线路状态管理水平有了明显提高。

  19. Research on Special Maintenance Tool of Straight Line Tower Ground and OPGW Cable in Overhead Transmission Line%线路直线塔地线及光缆金具维护

    Institute of Scientific and Technical Information of China (English)

    杨军

    2014-01-01

    本文在对架空输电线路直线塔地线支架和地线、 OPGW光缆金具组装方式及杆塔荷载的分析计算基础上,结合机械设计基础理论,确定了初步的专用工具研制方案。通过自行购买材料、零部件,在加工、装配和试用过程中不断完善后,成功研制出一套地线、 OPGW光缆金具维护的专用工具。该专用工具通过在不同电压等级线路、荷载情况下的4次现场试用,完全满足对35 kV~500 kV线路通用通用直线塔地线、 OPGW光缆金具的维护工作,而且与传统的作业方法相比明显提高了作业安全性和工作效率。%Based on the basis of the calculation,combining with the basic mechanical design theory, and analysis of straight wire bracket and a ground wire,OPGW cable for overhead power transmission line and tower load, the special maintenance tool is pre-liminary designed. Through the purchase of materials, parts, continuous improvement in processing, assembly and trial process,successfully developed a set of wire,OPGW cable maintenance special tool. The special tool is through the field test for 4 times in different voltage grade line,load conditions,to meet the needs of 35 kV-500 kV line general linear tower wire,OPGW cable main-tenance work,and compared with the traditional operating method significantly improves the operation safety and efficiency.

  20. Estimation of the Frequency of Instantaneous Voltage Drops Dependent on Arrangement of Line Surge Arresters

    Science.gov (United States)

    Kawamura, Hironao; Kozuka, Masahiro; Itamoto, Naoki; Shinjo, Kazuo; Ishii, Masaru

    Lightning faults on transmission lines often cause instantaneous voltage drops in power systems. Influences of instantaneous voltage drops become increasingly serious in high technology industries etc. As countermeasures of instantaneous voltage drops, uninterruptible power supplies (UPS) are employed. On the other hand, line surge arresters are installed on transmission lines increasingly as one of the effective countermeasures of double-circuit faults caused by lightning strokes. Additionally, the arresters are effective as one of the reduction methods for the frequency of instantaneous voltage drops. In this paper, the frequency of instantaneous voltage drops reduced by installation of line surge arresters on transmission lines is estimated by employing EMTP analysis. Also, the accuracy of the method in estimating the frequency of instantaneous voltage drops in power systems is evaluated through comparison with experience.

  1. Advances of Investigation on Rain-wind Induced Vibration of Overhead Transmission Lines%架空输电线路风雨激振研究进展

    Institute of Scientific and Technical Information of China (English)

    周超; 李力; 刘衍平

    2015-01-01

    架空输电线路在特定的风雨耦合条件下会诱发风雨激振问题.风雨激振使得高压输电线-塔体系更易于发生动力失稳乃至断线倒塔,制约着架空输电线路的安全稳定运行.为此,针对架空导线风雨激振问题,详细叙述风雨激振的严重危害,介绍包括现场观测、风洞试验、理论分析、数值流体计算等相关研究方法.分析风雨激振的诱发机制、关键影响因素、现有的振动抑制措施以及新形势下亟需解决的问题,为该问题的进一步研究提供思路.%Rain-wind induced vibration occurs very often for overhead transmission lines. This kind of vibration can lead to the aerodynamic instability of transmission tower-line system and even break the tower, also restricts the security and stability of operation of the overhead transmission lines. In this paper, the serious harm of the rain-wind induced vibration was elaborated. The methods for field observation, wind tunnel test, the theoretical analysis and numerical computation of fluid dynamics for the transmission lines were introduced. The mechanism and key influencing factors of rain-wind induced vibration were analyzed. Recent results in the research of anti-vibration measures were reviewed. Moreover, some hot problems which need to be further studied were proposed.

  2. Voltage Regulation and Line Loss Minimization of Loop Distribution Systems Using UPFC

    Science.gov (United States)

    Sayed, Mahmoud A.; Takeshita, Takaharu

    This paper presents a new method for achieving line loss minimization and voltage regulation in the loop distribution systems, simultaneously. First, mathematical analysis of the line loss minimum conditions in the loop distribution systems is presented. Then, load voltage regulation is applied in the loop distribution system under line loss minimum condition. Reference angle of the desired load voltage is the main factor that can be used to minimize total line loss during load voltage control. In order to achieve these two objectives simultaneously, the UPFC (unified power flow controller), a typical FACTS (flexible AC transmission systems) device, that is capable of instantaneous control of transmission and distribution power flow, is used. Also, the UPFC control scheme to regulate the load voltage under line loss minimization is presented. The effectiveness of the proposed control scheme has been verified experimentally using laboratory prototype in a 200V, 6kVA system.

  3. Modalities of vegetation management beneath and in the vicinity of overhead power lines; Modalites de gestion de la vegetation sous et aux abords des lignes electriques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    This guidebook was elaborated in coordination with the French professional national center of forestry property (CNPPF), Electricite de France (EDF), the national federation of contractors of rural agricultural and forestry works (FNETARF), the national federation of the syndicates of sylviculture forestry owners (FNSPFS), the institute for forest development (IDF), the national forest office (ONF), the French manager of the power grid (RTE) and some local agriculture organizations. Its goal is to supply concrete answers to the questions concerning the management of vegetation in the direct vicinity of overhead power lines, and in particular the rights and obligations of land owners with respect to the maintenance of vegetation. This guidebook represents a first step towards the improvement of today's practices in this domain: legal and technical questions and answers, glossary, regulatory texts, useful addresses and bibliography. (J.S.)

  4. Complexity Quantification for Overhead Transmission Line Emergency Repair Scheme via a Graph Entropy Method Improved with Petri Net and AHP Weighting Method

    Directory of Open Access Journals (Sweden)

    Jing Zhou

    2014-01-01

    Full Text Available According to the characteristics of emergency repair in overhead transmission line accidents, a complexity quantification method for emergency repair scheme is proposed based on the entropy method in software engineering, which is improved by using group AHP (analytical hierarchical process method and Petri net. Firstly, information structure chart model and process control flowchart model could be built by Petri net. Then impact factors on complexity of emergency repair scheme could be quantified into corresponding entropy values, respectively. Finally, by using group AHP method, weight coefficient of each entropy value would be given before calculating the overall entropy value for the whole emergency repair scheme. By comparing group AHP weighting method with average weighting method, experiment results for the former showed a stronger correlation between quantified entropy values of complexity and the actual consumed time in repair, which indicates that this new method is more valid.

  5. On the Operation State and Maintenance Management of the Current Overhead Transmission Line%试论目前架空输电线路状态运行与维护管理

    Institute of Scientific and Technical Information of China (English)

    许金明

    2014-01-01

    This paper analyzes the operation state and maintenance management status of the current overhead transmission line and describes the improvement countermeasures to improve the overall efficiency of the operation state and maintenance management of the overhead transmission line.%文章分析目前架空输电线路状态运行与维护管理基本现状,介绍了架空输电线路状态运行与维护管理完善对策,以期提高该架空输电线路状态运行与维护管理整体效率。

  6. 110 kV Overhead Transmission Line Operation and Maintenance Strategy%110kV架空输电线路运行的影响因素与运维策略

    Institute of Scientific and Technical Information of China (English)

    李志军

    2015-01-01

    This paper briefly analyzes the factors affecting the safe operation of 110 kV overhead transmission line, and puts forward the maintenance strategy to ensure the safe operation of 110 kV overhead transmission lines, in order to provide a reference for future work.%简要分析了影响110 kV架空输电线路安全运行的因素,并提出了保证110 kV架空输电线路安全运行的维护策略,以期为日后的相关工作提供参考.

  7. 山火条件下的架空输电线路停运概率模型%A Probabilistic Model of Overhead Transmission Line Outage due to Forest Fire

    Institute of Scientific and Technical Information of China (English)

    宋嘉婧; 郭创新; 张金江; 王越; 盛鹍

    2013-01-01

    Some overhead transmission corridors pass through fire-prone regions such as mountain and rural areas, and forest fire greatly affects on transmission line reliability. At present, in the research on reliability model of overhead transmission line the condition of forest fire is seldom taken into account. Utilizing mathematical model of surface fire behavior caused by forest fire, the forest fire conditions obtained from this model are taken as input variables and led into the computation of reliability of overhead transmission line. Based on the reasons causing breakdown of air gap of overhead transmission line, corresponding probabilistic model of overhead transmission line outage is built, in which the air gap breakdown mechanism under forest fire is considered, to predict the outage probability due to phase-to-ground discharge and that due to phase-to-phase discharge. In case studies the affected times of overhead transmission line operation after the occurrence of forest fire are calculated and the outage probabilities of typical overhead transmission line under different forest fire conditions are given. Calculation results show that the proposed model can reflect the affect of forest fire on overhead transmission line reliability correctly.%由于输电走廊经常经过山区、农区等山火易发地带,山火已对输电线路可靠性产生重要影响.目前考虑山火状况对输电线路可靠性模型方面的研究较少,为此,以山火地表火行为数理模型为基础,将模型得出的山火状况作为输入量,引入输电线路可靠性计算中.基于山火导致输电线路空气间隙被击穿的原因,建立了相应的停运概率模型,预测相地放电与相间放电2种情况的停运概率.算例计算了某山火发生后将影响到线路运行的时间,并给出了典型的输电线路在不同山火状态下的停运概率,结果表明模型能够正确反映山火对输电线路可靠性的影响.

  8. Jet Stream Interrupter Gap Lightning Protection Device for 35 kV Overhead Transmission Lines%35kV架空输电线路间隙灭弧的研究

    Institute of Scientific and Technical Information of China (English)

    王巨丰; 黄维; 曲振旭; 刘儒

    2012-01-01

    To address the problem of lightning stroke on 35 kV overhead transmission lines, a jet stream interrupter gap lightning protection device (JSGLPD) for 35 kV overhead transmission lines was developed. When a lightning stroke on the transmission line causes AC flashover on insulator strings, the device is able to quickly cut off the power frequency freewheeling arc to effectively protect the insulator strings against ablation of the power frequency arc. The JSGLPD can achieve the function of limiting the external over-voltage on insulators and avoiding frequent tripping of circuit breaker. Moreover, the movement characteristics of electric arc in jet stream were investigated on the basis of an arc model, in which the arc is assumed to be a chain of small rigid cylindrical current elements, and the arc quenching process was discussed. In addition, a high speed camera system and an oscillograph were used to observe the changes in the current of arc, and the result shows that the arc can be cut off instantly by the high-speed air jet stream.%为解决35 kV架空输电线路的雷击问题,研制了在35 kV架空输电线路上的防雷保护间隙喷射气流灭弧装置.该装置运用了“瞬时疏导”的防雷理念,能够在线路发生雷击闪络时有效地保护绝缘子串免受工频电弧的灼烧,在疏导雷电能量后能够迅速切断工频续流电弧,实现既可以限制绝缘子的外部过电压又可以避免断路器频繁跳闸的功能.笔者在链式电弧模型的基础上结合激波理论研究喷射气流条件下电弧的运动,对电弧的熄灭过程进行了讨论.在高压试验中借助高速摄像机和数字示波器,获取了在高速气流作用下电弧被迅速熄灭的过程图像和数据.

  9. Voltage Stability of Long Transmission Line Equipped with a Thyristor Controlled Series Capacitor

    Directory of Open Access Journals (Sweden)

    Prechanon Kumkratug

    2012-01-01

    Full Text Available Problem statement: Power-Voltage curve provides very important information for voltage stability analysis. The exact long transmission line model consists of the resistance and the reactance. The resistance causes in the active line loss. It is not easy task to achieve the power-voltage curve characteristics of power system with the exact long line model equipeed with a Thyristor Controlled Series Capacitor (TCSC. Approach: This study applies the concept of the Newton-Raphson method to iteratively solve the nonlinear power flow equations. The Power-Voltage (P-V curve charateristic of the system without line loss and with line loss are plotted and compared on various cases. Results: It is found from the study that the resistance of the line obviously provides the negative effects on the voltage stability. The line loss causes in the decrement of the critical point. In addition, it is found that the leading power factor can increase the critical point of P-V curve. Conclusion: The exact long line model should be considered for voltage stability analysis of the system with the long transmission line.

  10. Voltage Stability of Medium Transmission Line Equipped with a Thyristor Controlled Series Capacitor

    Directory of Open Access Journals (Sweden)

    Prechanon Kumkratug

    2012-01-01

    Full Text Available Problem statement: Power-Voltage curve provides very important information for voltage stability analysis. The exact medium transmission line model consists of the resistance and the reactance. The resistance causes in the active line loss. It is not an easy task to achieve the power-voltage curve characteristics of power system with the exact medium line model equipped with a. Thyristor Controlled Series Capacitor (TCSC. Approach: This study applies the concept of the Newton-Raphson method to iteratively solve the nonlinear power flow equations. The Power-Voltage (P-V curve characteristic of the system without line loss and with line loss are plotted and compared with various cases. Results: It is found from the study that the resistance of the line obviously provides the negative effects on the voltage stability. The line loss causes in the decrement of the critical point. In addition, it is found that the leading power factor can increase the critical point of P-V curve. Conclusion: The exact medium line model should be considered for voltage stability analysis of the system with the medium transmission line.

  11. Power-Voltage Characteristics of Power System with the Long Transmission Line

    Directory of Open Access Journals (Sweden)

    Prechanon Kumkratug

    2012-01-01

    Full Text Available Problem statement: Power- Voltage curve provides very important information for voltage stability analysis. The exact long transmission line model consists of the resistance and the reactance. The resistance causes in the active line loss. It is not easy task to achieve the power-voltage curve characteristics of power system with the exact long line model. Approach: This study applies the concept of the Newton-Raphson method to iteratively solve the nonlinear power flow equations. The Power-Voltage (P-V curve characteristic of the system without line loss and with line loss are plotted and compared on various cases. Results: It is found from the study that the resistance of the line obviously provides the negative effects on the voltage stability. The line loss causes in the decrement of the critical point. In addition, it is found that the leading power factor can increase the critical point of P-V curve. Conclusion: The exact long line model should be considered for voltage stability analysis of the system with the long transmission line.

  12. Study of High Voltage AC Underground Cable Systems

    DEFF Research Database (Denmark)

    da Silva, Filipe Miguel Faria; Bak, Claus Leth; Wiechowski, Wojciech T.

    2010-01-01

    High-Voltage cables are starting to be more often used to transmit electric energy at high-voltage levels, introducing in the electric grid phenomena that are uncommon when using Overhead Lines. Under the phenomena worthy of special attention are those related with the cable energisation and deen...

  13. Effect of voltage sags on digitally controlled line connected switched-mode power supplies

    DEFF Research Database (Denmark)

    Török, Lajos; Munk-Nielsen, Stig

    2012-01-01

    Different voltage disorders like voltage fluctuations, sags, frequency variations may occur in the power supply networks due to different fault conditions. These deviations from normal operation affects in different ways the line connected devices. Standards were developed to protect and ensure i...

  14. Development of Fiber Optically Driven Instrument for High-voltage Line Current

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The measurement theorem of fiber optically driven instrument for high-voltage line current is presented. The PLL voltage-frequency-narrow pulse principle and its micro-consumption mechanism are proposed, followed by analysis on the two main factors affecting PLL measurement precision. A software design scheme using 80C196KB micro-controller is introduced. The experiment result is satisfactory.

  15. Uncertainty evaluation in the measurement of power frequency electric and magnetic fields from AC overhead power lines.

    Science.gov (United States)

    Ztoupis, I N; Gonos, I F; Stathopulos, I A

    2013-11-01

    Measurements of power frequency electric and magnetic fields from alternating current power lines are carried out in order to evaluate the exposure levels of the human body on the general public. For any electromagnetic field measurement, it is necessary to define the sources of measurement uncertainty and determine the total measurement uncertainty. This paper is concerned with the problems of measurement uncertainty estimation, as the measurement uncertainty budget calculation techniques recommended in standardising documents and research studies are barely described. In this work the total uncertainty of power frequency field measurements near power lines in various measurement sites is assessed by considering not only all available equipment data, but also contributions that depend on the measurement procedures, environmental conditions and characteristics of the field source, which are considered to increase the error of measurement. A detailed application example for power frequency field measurements is presented here by accredited laboratory.

  16. Study and Experiment on Non-Contact Voltage Sensor Suitable for Three-Phase Transmission Line.

    Science.gov (United States)

    Zhou, Qiang; He, Wei; Xiao, Dongping; Li, Songnong; Zhou, Kongjun

    2015-12-30

    A voltage transformer, as voltage signal detection equipment, plays an important role in a power system. Presently, more and more electric power systems are adopting potential transformer and capacitance voltage transformers. Transformers are often large in volume and heavyweight, their insulation design is difficult, and an iron core or multi-grade capacitance voltage division structure is generally adopted. As a result, the detection accuracy of transformer is reduced, a huge phase difference exists between detection signal and voltage signal to be measured, and the detection signal cannot accurately and timely reflect the change of conductor voltage signal to be measured. By aiming at the current problems of electric transformation, based on electrostatic induction principle, this paper designed a non-contact voltage sensor and gained detection signal of the sensor through electrostatic coupling for the electric field generated by electric charges of the conductor to be measured. The insulation structure design of the sensor is simple and its volume is small; phase difference of sensor measurement is effectively reduced through optimization design of the electrode; and voltage division ratio and measurement accuracy are increased. The voltage sensor was tested on the experimental platform of simulating three-phase transmission line. According to the result, the designed non-contact voltage sensor can realize accurate and real-time measurement for the conductor voltage. It can be applied to online monitoring for the voltage of three-phase transmission line or three-phase distribution network line, which is in accordance with the development direction of the smart grid.

  17. Study and Experiment on Non-Contact Voltage Sensor Suitable for Three-Phase Transmission Line

    Directory of Open Access Journals (Sweden)

    Qiang Zhou

    2015-12-01

    Full Text Available A voltage transformer, as voltage signal detection equipment, plays an important role in a power system. Presently, more and more electric power systems are adopting potential transformer and capacitance voltage transformers. Transformers are often large in volume and heavyweight, their insulation design is difficult, and an iron core or multi-grade capacitance voltage division structure is generally adopted. As a result, the detection accuracy of transformer is reduced, a huge phase difference exists between detection signal and voltage signal to be measured, and the detection signal cannot accurately and timely reflect the change of conductor voltage signal to be measured. By aiming at the current problems of electric transformation, based on electrostatic induction principle, this paper designed a non-contact voltage sensor and gained detection signal of the sensor through electrostatic coupling for the electric field generated by electric charges of the conductor to be measured. The insulation structure design of the sensor is simple and its volume is small; phase difference of sensor measurement is effectively reduced through optimization design of the electrode; and voltage division ratio and measurement accuracy are increased. The voltage sensor was tested on the experimental platform of simulating three-phase transmission line. According to the result, the designed non-contact voltage sensor can realize accurate and real-time measurement for the conductor voltage. It can be applied to online monitoring for the voltage of three-phase transmission line or three-phase distribution network line, which is in accordance with the development direction of the smart grid.

  18. The theoretical foundations for calculating the technical parameters for low- tension overhead electricity lines for use in telecommunications

    Directory of Open Access Journals (Sweden)

    Henry Arturo Bastidas Mora

    2010-05-01

    Full Text Available This article presents the properties of electric power networks for use as a channel for transmitting telecommunications signals. It starts by exploring the principles and theoretical basis for calculating power lines’ critical technical parameters, referring in detail to the following primary parameters: inductance, capacitance, conductance and resistance. It then deals with e secondary para- meters (most useful from a telecommunications perspective: characteristic impedance and propagation constant (the attenuation constant being the latter’s real component. Different topologies and low- and medium-tension aerial power line structures are verified; a mathematical model is then proposed to analyse their behaviour at high frequencies, extending to most aerial electric power distribution systems in Colombia. This work includes some of the results from previous research which was known as “U- sing power line telecommunications (PLT technology for designing a solution for accessing the broadband internet in rural areas of Colombia” by the present author and the Pilot University of Colombia. The proposed mathematical model provides a tool for making theoretical calculations applicable to PLT.

  19. Fast Protection Scheme for Overhead Transmission Lines of VSC-based HVDC Grid%柔性直流电网架空线路快速保护方案

    Institute of Scientific and Technical Information of China (English)

    王艳婷; 张保会; 范新凯

    2016-01-01

    The voltage source converter(VSC)-based high voltage direct current(HVDC)grid technology is an effective means for large-scale integration of clean energy.The fast DC line protection technology is one of the main challenges to HVDC grids. Based on the Zhangbei HVDC grid project,this paper proposes a fast protection scheme for overhead transmission lines of bipolar VSC-based HVDC grids equipped with DC circuit breakers.The protection is based on local measurements featuring fast response speed.The voltage gradient is used to detect faults rapidly,and the voltage derivative criterion is adopted to identify the protection zone in which the fault occurs thanks to the smoothing effect of the fault current limiter.And the faulty pole is identified according to the different propagation characteristics between the line mode and zero mode voltage,ensuring the selectivity of the protection as well as high reliability.The Zhangbei HVDC grid model is built in PSCAD/EMTDC and the performance of the proposed protection scheme is verified by simulation results of various fault conditions,as well as different operation modes of the HVDC grids.%基于柔性直流输电的直流电网技术,是大规模清洁能源接入电网的有效手段,直流电网快速线路保护是其面临的重要技术挑战之一。以国内计划建设的张北直流电网工程为背景,提出了一套适用于全网配置直流断路器、采用架空线输电的对称双极直流电网线路快速保护方案。保护仅利用单端信息进行故障判别,且保护数据窗短,满足速动性的要求;保护采用电压梯度快速检测故障,利用限流电抗器对故障电压信号的平滑作用实现故障区间的判别,并根据零模与一模电压传播特性的差异判定故障极,实现保护的选择性与高可靠性。结合直流电网的PSCAD模型,验证了所提出方案在不同故障情况下的保护性能,并分析了保护对运行方式改变的适应性。

  20. Research of Characteristics of the Low Voltage Power Line in Underground Coal Mine

    Science.gov (United States)

    Wei, Shaoliang; Qin, Shiqun; Gao, Wenchang; Cheng, Fengyu; Cao, Zhongyue

    The power line communications (PLCs) can count on existing electrical connections reaching each corner in the locations where such applications are required, so signal transmission over power lines is nowadays gaining more and more interest for applications like internet. The research of characteristics of the low voltage power line is the fundamental and importance task. This work presents a device to test the characteristics of the low voltage power line. The low voltage power line channel characteristics overground and the channel characteristics underground were tested in using this device. Experiments show that, the characteristics are different between the PLCs channel underground coal mine and the PLC channel overground. Different technology should be adopted to structure the PLCs channel model underground coal mine and transmit high speed digital signal. But how to use the technology better to the high-speed digital communication under coal mine is worth of further studying.

  1. High voltage transmission lines studies with the use of artificial intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Ekonomou, L. [A.S.PE.T.E. - School of Pedagogical and Technological Education, Department of Electrical Engineering Educators, N. Heraklion, 141 21 Athens (Greece)

    2009-12-15

    The paper presents an alternative approach for the studies of high voltage transmission lines based on artificial intelligence and more specifically artificial neural networks (ANNs). In contrast to the existing conventional-analytical techniques and simulations which are using in the calculations empirical and/or approximating equations, this approach is based only on actual field data and actual measurements. The proposed approach is applied on high voltage transmission lines in order to calculate the lightning outages, on grounding systems in order to assess the grounding resistance and on high voltage transmission lines' polluted insulators in order to estimate the critical flashover voltage. The obtained results are very close to the actual ones for all three case studies, something which clearly implies that the ANN approach is well working and has an acceptable accuracy, constituting an additional tool of electric engineers. (author)

  2. 基于FMECA的110kV架空导线断线可靠性分析%Broken Line Reliability Analysis on 110 kV Overhead Transmission Line Based on FMECA

    Institute of Scientific and Technical Information of China (English)

    崔景顺; 高广德; 刘畅

    2013-01-01

    Overhead conductor is usually adopted in UHV transmission line. For most of the overhead transmission lines are running in the wild and affected by various natural environment factors and human impact, the wires are prone to broken strands malfunction, or even the entire root wire fracture and cause the accidents. 500 kV and above the level of the transmission line have rarely off shares and disconnection malfunction. However, off shares accidents are the most common in the 110 kV transmission line. In the form of overhead lines failure, it is influenced by many factors. This paper is based on the FMECA reliability analysis method, and gives predictive analysis of off shares and even short梩erm failure factors occured. All possible failures modes of circuit components, the causes and impact of the failure models are determined in the design, construction and operation. The possible potential weak links are found out, prevention and compensation measures are put forward.%在高压电力输送过程中,较多采用的是架空导线的输送方式.由于架空输电线路大部分是在野外运行,长期受到各种自然环境以及人为的影响,导线很容易发生断股故障,甚至整根导线断裂,引起事故.500kV以及以上等级的线路很少出现断股和断线故瘴,而110 kV线路断股事故最为常见.在架空导线的失效形式中,受到很多因素的影响.采用基于FMECA的可靠性分析方法,对导线可能会发生断股乃至断线的故障因素进行预测分析,确定线路在设计、施工、运行的过程中所有可能发生的故障模式,及每个故障模式的产生原因和影响,找出潜在的、可能的薄弱环节,并提出可以采取的预防补偿措施.

  3. 架空输电线路除冰机器人的研制%The Manufacturing of a Deicing Robot for Overhead Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    张峰; 郭锐; 赵金龙; 曹雷

    2011-01-01

    Deicing with robotics could be operated on line for the transmission lines to prevent damage.For single line deicing between two towers,a practical deicing robot for overhead transmission lines is manufactured.The robot deices by impacting on ice with fixed tools.Three driving wheels and pressure wheel mechanism could increase friction for driving.A locking mechanism and anti-overturning mechanism are developed for high stability and safety during working.The robot has the advantages of light weight,small size and high deicing efficiency.Many experiments have been carried out on simulative lines and 500 kV live-lines.It is varified that the deicing speed is more than 0.13 m/s,even through the ice diameter is 50 mm.%利用机器人技术实现输电线路在线除冰,可以在不停电的情况下提早消除覆冰隐患,防止重大灾害的发生。针对一档内单股线除冰作业,设计并研制出一种实用性较高的输电线路除冰机器人。该机器人采用固定刀具,前推撞击方式除冰;3个并行排列同时驱动的行走轮与压紧轮机构配合增大摩擦驱动力;采用的锁紧机构和防倾倒机构,确保作业稳定,保障作业安全。该机器人体积小、重量轻、除冰效率高,已经在模拟线路和500 kV带电线路等进行过多次除冰试验,在直径超过50 mm的高硬度覆冰环境下,平均除冰速度可达0.13 m/s。

  4. Trees and Shrubs for Overhead Utility Easements

    OpenAIRE

    Appleton, Bonnie Lee, 1948-2012; French, Sue (Sue C.); Johnson-Asnicar, Brenda; Relf, Diane; Day, Susan D.; Nunnally, Richard, 1947-; Vest, John

    2009-01-01

    Trees are one of the major causes of power outages in areas of overhead utility lines due to direct tree contact with lines, or to trees or tree limbs falling on the lines. This publication covers conflict resolution options and tree selection and planting when dealing with landscaping around power lines.

  5. Measurements for validation of high voltage underground cable modelling

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Gudmundsdottir, Unnur Stella; Wiechowski, Wojciech Tomasz

    2009-01-01

    This paper discusses studies concerning cable modelling for long high voltage AC cable lines. In investigating the possibilities of using long cables instead of overhead lines, the simulation results must be trustworthy. Therefore a model validation is of great importance. This paper describes...

  6. The Issues of Reactive Power Compensation in High-voltage Transmission Lines

    Directory of Open Access Journals (Sweden)

    Zbigniew Lubośny

    2015-06-01

    Full Text Available This paper discusses the selection of compensation shunt reactors for a double-circuit 400 kV transmission line using the example of the newly built Elk Bis – Alytus transmission line. The analysis takes into account various conditions of the power system. The published results relate to voltage levels in steady states and during switching processes and short circuits.

  7. Line edge roughness induced threshold voltage variability in nano-scale FinFETs

    Science.gov (United States)

    Rathore, Rituraj Singh; Sharma, Rajneesh; Rana, Ashwani K.

    2017-03-01

    In aggressively scaled devices, the FinFET technology has become more prone to line edge roughness (LER) induced threshold voltage variability. As a result, nano scale FinFET structures face the problem of intrinsic statistical fluctuations in the threshold voltage. This paper describes the all LER induced variability of threshold voltage for 14 nm underlap FinFET using 3-D numerical simulations. It is concluded that percentage threshold voltage (VTH) fluctuations referenced with respect to rectangular FinFET can go up to 8.76%. This work has also investigated the impact of other sources of variability such as random dopant fluctuation, work function variation and oxide thickness variation on threshold voltage.

  8. Research on On-Line Coordinated Control Strategy to Improve the Voltage Vulnerability after Disturbance

    Institute of Scientific and Technical Information of China (English)

    Qun-Ying Liu; Qi-Fang Liu; Deng Liu; Yong-Feng Liao

    2014-01-01

    The on-line coordinated control strategy among multi-voltage controls is important to keep voltage security in post-fault systems. Based on the wide area measuring information, the energy function, which can qualify the impacts of the different control actions on voltage of different nodes, is proposed. And then, considering the impacts of different control actions on the node voltage being treated as a weight matrix, the energy margin is used as the objective function and the reactive power margin is innovatively used as the constraint to regulate the control actions globally according to the weight values. At last, the objective functions are solved to get the optimal global coordinated control strategies. The proposed method is identified in an IEEE-30 Bus system and the simulation results show that it effectively improves the voltage stability.

  9. Design and Implementation of Visual Inspection System for Overhead Line in Transmission Line%输电线路中的架空线可视化巡视系统的设计与实现

    Institute of Scientific and Technical Information of China (English)

    黄晓红; 王丹; 叶廷东; 刘波

    2015-01-01

    This paper presents the design and implementation of the structure and function of the visual inspection system of overhead lines in the transmission line. The project can effectively improve effect of power transmission line operation and maintenance, the lofty mountains and harsh environment, requiring frequent inspection area and no 3G network coverage where the wireless mesh network) transmission line of video surveillance, also have a strong centralized monitoring center platform, achieve controllable transmission lines, in control, fundamentally change the transmission mode of production management.%本文介绍了输电线路中的架空线可视化巡视系统的结构和功能的设计与实现. 该项目可有效地提高输电线路运行维护的效果, 实现对高远山区、 环境恶劣、 需要频繁巡视区域和无3 G网络覆盖地方 (利用无线Mesh网络) 的输电线路进行视频监控, 同时具备强大的集中监控中心平台, 实现输电线路的可控、 在控, 从根本上转变输电生产管理模式.

  10. Report about the contribution of new technologies to the burial of high and very-high voltage power lines; Rapport sur l'apport de nouvelles technologies dans l'enfouissement des lignes electriques a haute et tres haute tension

    Energy Technology Data Exchange (ETDEWEB)

    Kert, Ch. [Assemblee Nationale, 75 - Paris (France)

    2001-12-01

    Today, high voltage overhead power lines are badly perceived by the population in particular in urban areas and in areas with remarkable landscapes, for their visual impact on the environment and for their possible effect on human health. With the increase of the domestic and foreign power demand, the high voltage grid will develop in the future and the partial burial of power lines can be the first steps towards a solution to these problems. This report makes a worldwide status of the state-of-the-art of power line burial technologies, all voltages considered, and then focusses on the very-high voltage challenge which encounters the most important technological and economical constraints. The technical feasibility has been proven but the lowering of costs needs the development of a real European market of power lines burial. (J.S.)

  11. VSC-HVDC Technology Suitable for Bulk Power Overhead Line Transmission%大容量架空线柔性直流输电关键技术及前景展望

    Institute of Scientific and Technical Information of China (English)

    徐政; 薛英林; 张哲任

    2014-01-01

    To make the voltage source converter based high voltage direct current (VSC-HVDC) system extend to long distance bulk power overhead line transmission is the inherent requirement of energy source distribution in China and future trend of power grid development. However, the challenges associated with the state-of-the-art VSC-HVDC system mainly include: a) difficulty to handle dc fault, b) less transmission capacity compared with the traditional HVDC systems, and c) difficulty to select grounding point. For the first challenge, this paper analyzes vulnerability of the existing topologies against dc faults, focusing on an overview of the topologies with dc fault ride-through capability. According to the characteristics of dc fault processing, these topologies can be divided into three basic types. Furthermore, advantages and defects of these typical topologies are discussed. For the second and third challenges, to achieve a high voltage and power level, a bipolar VSC-HVDC topology with assembly converter is proposed. In this topology, each pole consists of several basic converter units (BCU) in series or in parallel; between the positive pole and the negative pole is the neutral bus which is connected to the ground electrode. Furthermore, the advantages and shortcomings of the possible grounding modes are summarized. At last, according to the unidirectional energy flow characteristics of China, two basic VSC-HVDC structures are analyzed.%柔性直流输电技术(voltage source converter based high voltage direct current,VSC-HVDC)应用于远距离大容量架空线输电是实现我国能源资源优化配置的客观要求,也是电网技术发展的未来趋势。目前柔性直流输电技术扩展到架空线输电场合所面临的关键问题有:直流线路故障难以快速清除、输送容量难以与传统直流输电相媲拟、主接线方式和接地方式选择原则还没有定论等。针对问题1,分析现有工程所采用的拓扑结构

  12. Аnalysis of factors influencing physical and mechanical properties of icing on wires and cables of overhead power transmission lines

    OpenAIRE

    Mezerjy, A. J.; Zanykhaylo, Y. O.

    2014-01-01

    У статті розглянуто фактори, які впливають на фізико-механічні властивості ожеледі на проводах і тросах повітряних ліній електропередачі. В статті була побудована структурна схема, виявлено ступінь впливу різних факторів на фізико-механічні властивості ожеледі. The paper considers factors influencing physical and mechanical properties of icing on wires and cables of overhead power transmission lines. The paper presents a schematic diagram, founds the degree of influence of various...

  13. Corona noise model of high-voltage AC transmission lines and engineering applications

    Institute of Scientific and Technical Information of China (English)

    Wu Jiuhui; Di Zelong

    2013-01-01

    In order to predict the levels of corona noise from high-voltage alternating current (AC) transmission lines,the mechanism of corona noise and the corresponding theoretical prediction model are investigated.On the basis of Drude model,the motion of positive and negative ions produced by high-voltage corona is analyzed,and the mechanism of corona noise is discovered.The theoretical prediction model is put forward by using Kirchhoff formula,which is verified by the well agreement between our result and others',considering the case of three-phase single lines.Moreover,the calculation results show that for both single and bundled lines,the sound pressure level of the typical frequency,i.e.twice the power frequency,attenuates slowly and leads to an obviously interferential phenomenon near the transmission lines,but the level of the bundled lines is smaller than that of the single ones under the same transmission voltage.Based on the mechanism of corona noise and the prediction model,it is obvious that bundled lines and/or increased line radius can be adopted to reduce corona noise in the practical engineering applications effectively.This model can also provide a theoretical guidance for the high-volt-age AC transmission line design.

  14. Combination of Reactive Current Droop Compensation and Line Drop Compensation for Improving Voltage Stability

    Institute of Scientific and Technical Information of China (English)

    TIAN Qing; LIN Xiang-ning

    2009-01-01

    Recent events related to power system failure have shown that voltage collapse can be a cause of widespread outages.The thrust of this paper is to discuss and establish means of mitigating system voltage instability by using a combination of both reactive current droop compensation and line drop compensation.It is shown that the point that the voltage regulator controls can be defined by a new method which is based on a widely accepted vohage stability analysis tool.This tool can be used to determine which generators will have an impact on the maximum permissible loading of a bus.Dynamic analysis was carried out on the CIGRE Nordic test system to study the impact of control point location on time to collapse and it is shown that the new scheme can improve the voltage stability.

  15. VOLTAGE STABILITY OF SHORT TRANSMISSION LINE EQUIPPED WITH A THYRISTOR CONTROLLED SERIES CAPACITOR

    Directory of Open Access Journals (Sweden)

    Prechanon Kumkratug

    2012-01-01

    Full Text Available It is becoming increasingly important to fully utilize the existing transmission system assets due to environmental legislation, rights-of-way issues, costs of construction and deregulation policies that introduced in recent years. The Thyristor Controlled Series Capacitor (TCSC has been proposed for the better control power flow and dynamic performance. The exact short transmission line model consists of the resistance and reactance. Most of previous researches studies voltage stability performance of the TCSC in SMIB System with neglecting the resistance of the line. Thus the fully capability of the TCSC on voltage stability improvement of power system may not be applied. The consideration of the resistance causes in the difficulty of deriving the mathematical model. This study investigates the effect of the TCSC on voltage stability of the power system with consideration the exact short transmission line mode. The concept of two-port network is applied to simplify the mathematical model of the power system. The proposed method is tested on sample system and compared on various cases. The first swing of rotor angle curve of the faulted system without resistance is obviously higher than that of with resistance whereas the second swing of the faulted system without resistance is slightly less than that of with resistance. The system with a TCSC can improve voltage stability of power system. It was found from this study that the TCSC and resistance of the line can improve first swing of rotor angle. However, the resistance of the line provides the negative effect on second swing of rotor angle. The simulation results indicate that for practical short line, the resistance is very import parameters for evaluating voltage stability of power system.

  16. 76 FR 4575 - Safety Zone; Repair of High Voltage Transmission Lines to Logan International Airport, Saugus...

    Science.gov (United States)

    2011-01-26

    ... to Logan International Airport, Saugus River, Saugus, MA AGENCY: Coast Guard, DHS. ACTION: Notice of... of high voltage transmission lines to Logan Airport. This safety zone is required to provide for the... feed Logan Airport. The safety zone will be enforced immediately before, during, and after the start...

  17. 110 kV双回线路管型复合材料杆避雷线架设与接地方案研究%Erection Scheme of Overhead Grounding Wire on Composite Material Pole and Its Grounding for 110 kV Double Circuit Overhead Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    李志军; 陈维江; 戴敏; 李志政; 李汉明; 邓世聪

    2014-01-01

    我国学者尝试在雷电活动强烈、污秽严重地区的110 kV架空线路应用复合材料绝缘杆,以提高相对地空气间隙距离和爬电距离。然而绝缘水平的提高,复合材料杆还是否需要架设避雷线以及避雷线接地引下线,是防雷面临的关键技术问题之一。针对典型110 kV复合材料杆,对比研究未架设避雷线的复合材料杆与架设避雷线的同电压等级、相同导线高度铁塔线路的雷电性能,考虑2种杆塔线路引雷能力、雷电冲击绝缘强度以及建弧率等因素的差异,发现:2种杆塔线路引雷能力间的差异可以忽略;未架设避雷线的复合材料杆雷电冲击绝缘强度是铁塔的3.5倍,建弧率为铁塔的53%,但是反击耐雷水平仅为24.5 kA,雷击跳闸率高达1.13次/(100 km⋅a),均明显劣于铁塔。据此,推荐110 kV复合材料杆架设避雷线。然后,对比估算避雷线不同接地方案下雷电性能的差异发现:避雷线若不经引下线接地,则复合材料杆雷电性能明显劣于铁塔,但若经引下线逐杆接地,则雷电性能显著优于铁塔。因此,提出避雷线应逐杆接地。综上所述,110 kV 复合材料杆线路防雷接地方案应当采用架设避雷线,且通过金属引下线逐杆接地的设计。%It is attempted for Chinese scholars to apply insulation pole composed of composite material in the erection of 110 kV overhead transmission lines located at the regions with strong lightning activity and/or serious pollution to enhance the phase-to-ground air gap distance and creepage distance effectively. However, with the enhancement of insulation level whether the overhead ground wire should be erected on the composite material pole as well as its grounding downlead should be equipped are key problems that the lightning protection technology has to be faced with. As to the composite material pole for 110 kV transmission lines, the lightning

  18. Power Improvement of Transmission Line Using High Voltage Direct Current (Hvdc Transmission System

    Directory of Open Access Journals (Sweden)

    Lasisi, H

    2016-08-01

    Full Text Available The use of long EHV (Extremely High Voltage ac lines for the transmission of electrical energy increases the line reactance and susceptance which limits the thermal loadings on the line in order to keep sufficient margin against transient instability. With the scheme proposed in this paper, it is possible to load the lines very close to their limit with zero reactance and susceptance. The conductors are allowed to carry usual ac along with dc superimposed on it. The added dc power flow does not cause any transient instability. The scheme comprises a twelve-pulse bridge rectifier, dc-links, pulse width modulated (PSW-voltage sourced inverter (VSI and converter transformers. The master current controller is used to implement the scheme which senses ac current and regulates the dc current orders for converters online such that conductor current never exceeds its thermal limit. This paper gives the feasibility of converting a double circuit ac line into composite ac–dc power transmission line given the advantage of stability improvement, damping oscillations, voltage stabilization and reactive power compensation for ac weak buses. Simulation and experimental studies using MATLAB (Matrix Laboratory are carried out for the coordinated control as well as independent control of ac and dc power transmissions.

  19. The hotline in the grid. Higher temperatures with overhead lines can help to transport additional electricity; Der heisse Draht im Netz. Hoehere Temperaturen bei Freileitungen koennen helfen, Stromueberschuesse zu transportieren

    Energy Technology Data Exchange (ETDEWEB)

    Michels, Andreas; Friedrich, Uwe

    2016-11-01

    The electricity grid that has been used for decades reaches its limits when transporting increasing amounts of electricity over long distances. There are already limiting bottlenecks. One way to integrate more wind and solar power into the grid is provided by overhead lines with a higher maximum temperature. These can transport more electricity, enabling grid congestion to be avoided. One problem, though, is that metals expand more at high temperatures. As a result the line lengthens and sags more. However, special high-temperature conductors can provide a remedy here.

  20. Increased deposition of polychlorinated biphenyls (PCBs) under an AC high-voltage power line

    Science.gov (United States)

    Öberg, Tomas; Peltola, Pasi

    2009-12-01

    There is considerable public concern regarding the potential risks to health of electromagnetic fields in general and high-voltage power lines in particular. As epidemiological findings are not supported by a clearly defined mechanism of direct magnetic field interactions with the human body, potential indirect effects are of interest. It has been suggested that an increased exposure to chemical pollutants could occur near high-voltage power lines due to formation and deposition of charged aerosols. The current study reports empirical evidence that seems to support this hypothesis. The deposition of 18 congeners of polychlorinated biphenyls (PCBs) was studied by collecting samples of pine needles under a 400 kV AC power line and at reference sites in the vicinity. Compared to the reference sites, the average deposition of PCB congeners under the power line was almost double. This difference between the two groups of samples was statistically significant. While it is premature to draw any conclusions regarding the human exposure near high-voltage power lines, the issue deserves attention and further investigations.

  1. Comprehensive Analysis of Lightning Performance of Overhead Power Distribution Line with Varied Ground Obliquity%不同地形条件下架空配电线路的防雷分析

    Institute of Scientific and Technical Information of China (English)

    刘靖; 刘明光; 屈志坚; 刘铁

    2011-01-01

    In order to take lightning problem into consideration comprehensively, we introduced a new model for calculating the lightning outage rate of overhead power distribution line due to direct and indirect lightning strokes. By establishing an improved EGM model of overhead distribution line based on striking distance theory, combining with probability density function of lightning current, we solved the attract range of overhead line, which possesses a nonlinear relationship with line height for different district. Taking the Rusck's formula into consideration, basing on Generalized Integral method, we put forward a new arithmetic for calculating the lightning outage rate which includes indirect lightning. By calculation of two real 10 kV power distribution line, the new method is practical and accurate. The results show that indirect strokes are the main cause of lightning trip out, and for analyzing the lightning performance of overhead power distribution lines, the indirect lightning must be taken into consideration.%雷电活动直接影响到架空电力线路的安全稳定运行,为全面分析架空配电线路的雷害问题,提出了一种计入地形条件影响的分析新方法.先基于雷电的击距理论建立架空配电线路的引雷模型,结合雷电流的概率密度函数,求出了线路在不同高度和不同地形条件下的引雷范围与线路高度呈非线性关系;在确定线路引雷范围的基础上,分别计算了我国不同地域的架空线路直接雷击跳闸率;在对Rusck感应雷过电压研究成果分析的基础上,利用广义积分法得出了不同地形和地域的感应雷击跳闸率计算公式,而且架空配电线路中感应雷击跳闸次数占总雷击跳闸次数能达到83%,在架空线路的防雷分析中应该计入感应雷击的影响.2条10 kV架空线路算例与实际运行情况的对比验证了该计算方法的正确性.

  2. An Analysis of Magnetic Field Environment Near High-Voltage Power Lines and Contact Wires of Electric Railways

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Image method is used in this paper to calculate the value of magnetic field near high-voltage transmission lines and electric railways. Areas in which the magnetic field is less than 0.002 Gauss are given and the magnetic pollution of high-voltage power transmission lines and electric railways is discussed

  3. 架空线-电缆混合线路故障行波信号识别的研究%Research on Signal Recognition of Fault Traveling Wave for Cable-Overhead Mixed Line

    Institute of Scientific and Technical Information of China (English)

    王升; 徐伟

    2016-01-01

    ABSTRACT:This paper deals with fault recognition of the cable-overhead mixed line. With focus on the high resistance instantaneous ground fault and overhead line lightning fault of the mixed line,the paper proposes that the spectrum energy ratio of two characteristic frequency bands and waveform factor in the fault current traveling wave be used to distinguish non lightning strike fault,lightning fault and high impedance arc ground fault. The simulation model of the electromagnetic transient software is used to simulate the lightning strike on the cable-overhead mixed line;meanwhile, the fault traveling wave signal is identified. The simulation results show that the method proposed can effectively identify three kinds of faults.%针对架空-电缆混合线路中的高阻瞬时接地故障和架空线路雷击故障,提出采用电流故障行波的2个特征频带中的频谱能量比和波形系数来有效区分雷击非故障与雷击故障、高阻弧光接地故障的思想。利用电磁暂态软件建立仿真模型对架空-电缆混合线路的各种雷击情况进行了仿真,并且对故障行波信号进行了识别研究。仿真结果表明,采用的雷击识别方法可以有效识别不同类型的故障。

  4. BASIC PRINCIPLES OF ORGANIZING OF REPAIR OF A NEW GENERATION OF ELECTRIC POWER LINES 220 kV AND ABOVE

    Directory of Open Access Journals (Sweden)

    Postolaty V.M.

    2011-08-01

    Full Text Available The article describes the requirements for repair work on single circuit and double circuit overhead transmission lines of compact (VL and controlled self-compensating high voltage transmission power lines (CSHVL.These include overhead power lines to a new generation. They differ from traditional overhead using compact designs of supports, the convergence phase of the spans, circuits and substations connections to ways of regulation. With this new generation have the overhead compared to conventional overhead increased bandwidth and improved technical and economic indicators. The design and features of the new circuit overhead lines require a series of new campaigns for the organization of repairs, which are discussed in this article.

  5. 采用架空接闪线的防直击雷设计%Direct Lightning Protection Design of Overhead Lightning Line

    Institute of Scientific and Technical Information of China (English)

    黄旭; 李红旭

    2015-01-01

    Based on an example of a building,this paper introduced the lightning protection design of a certain first-class direct lighting protection buildings.The different layouts of adopting single lightning rod and single overhead lightning conductor were calculated and contrasted,and ultimately a plan which uses several overhead lightning conductors was confirmed.During the comparison,the protective range and its difference between dual overhead lightning conductors and designed specifications of lightning protection were analyzed.Finally,the rolling ball method was adopted to do the checking computation of the final plan,which confirms that it can play a role in direct lightning protection.%以某厂房为例,介绍了一类防雷建筑物的防直击雷设计。计算比较了独立接闪杆、架空接闪线的几种不同布置方式,并确定一种数根架空接闪线的方案。在方案比较中,着重分析了双架空接闪线的保护范围及其与防雷设计规范中的不同。采用滚球法对最终方案进行了防雷验算,确认其能起到防直击雷的作用。

  6. Implementation of Inverter with Flexible Voltage Control for A DC Line in a System

    Directory of Open Access Journals (Sweden)

    M. Mohanraj

    2014-02-01

    Full Text Available Due to raising demands in electric power it becomes more important to use the available energy sources efficiently and along with them the distributed generation comes into picture which means collection of energy from many small sources say RES. For distribute generation (DG systems a challenging issue is to smartly integrate renewable-energy sources into the grid as it leads to power quality problems under fault conditions. Another approach for meeting the power demand is to implement TEP .This work proposes an method which uses a control algorithm for inverters for providing a flexible voltage control using reference current generation under grid faults. The controlled inverter designed is used for inversion processes at the receiving end in a HVDC line. A system with three sources is considered, their performances if the three lines connecting three sources are AC lines and if one line is replaced with a DC line is studied. Keywords –

  7. Capacitive Coupling in Double-Circuit Transmission Lines

    Directory of Open Access Journals (Sweden)

    Zdenka Benesova

    2004-01-01

    Full Text Available The paper describes an algorithm for calculation of capacitances and charges on conductors in systems with earth wires and in double-circuit overhead lines with respect to phase arrangement. A balanced voltage system is considered. A suitable transposition of individual conductors enables to reduce the electric and magnetic fields in vicinity of overhead lines and to limit the inductive and capacitive linkage. The procedure is illustrated on examples the results of which lead to particular recommendations for designers.

  8. Automatic Meter Reading using Power Line Signaling and Voltage Zero-crossing Detection

    Directory of Open Access Journals (Sweden)

    C.L. Vasu

    2015-06-01

    Full Text Available In India, the electric power transmission and distribution loss is very high, about 7% in transmission and 26% in distribution. Though deployment of automated meter reading system will reduce losses, particularly in distribution, penetration of automated meter reading is low due to high costs involved. World over, the Two-Way Automatic Communications System (TWACS is the most widely used power line communications technology offering two-way communication between substation and end users. The TWACS introduces disturbance on the power system voltage for short durations near zero-crossing to generate the outbound (from substation to end user signal. To generate the inbound (from end user to substation signal, short duration current pulses are introduced, near voltage zero-crossings. Information is generated as a sequential combination of voltage disturbances for the outbound signal and current pulses for the inbound signal. The current study proposes a low-cost modification of the TWACS to reduce voltage and current harmonics. The proposed system has been modelled and simulated using SIMULINK/SIMPOWER Systems. The simulation results show that there is a reduction in voltage harmonics from 0.84 to 0.17% and in current harmonics from 2.07 to 1.10%.

  9. Experimental research on mechanical properties of high voltage transmission lines after the simulated wildfires

    Directory of Open Access Journals (Sweden)

    Wang Tianzheng

    2015-01-01

    Full Text Available In order to determine whether the mechanical performance after the fires of high voltage transmission lines meets the requirements of normal use, this article simulates the wildfire, and does the mechanical performance experiment of high voltage transmission lines(HVT lines after the simulated wildfires. The experiment studied the breaking force and elongation of each layer of 500kv HVT lines after the simulated wildfire. Experimental results show that, after fires, each layer of single aluminum wires of 500kv HVT lines have low breaking force which can be decreased obviously to half of that of new lines. For the steel core, decrease of breaking force is not obvious than aluminum wires, and with the increasing degree of wildfires, it increases gradually to a maximum of 35% of new steel lines’ breaking force. After wildfires, aluminum lines’ resistance ability of deformation decreases significantly, and its plastic deformation increases obviously during uniaxial tension. The steel core has little plastic deformation, and layers of aluminum become fluffy after fires. Therefore, the steel core main bearing load after wildfires.

  10. Voltage-guided ablation technique for cavotricuspid isthmus-dependent atrial flutter: refining the continuous line.

    Science.gov (United States)

    Jacobsen, Peter K; Klein, George J; Gula, Lorne J; Krahn, Andrew D; Yee, Raymond; Leong-Sit, Peter; Mechulan, Alexis; Skanes, Allan C

    2012-06-01

    Ablation of the cavotricuspid isthmus has become first-line therapy for "isthmus-dependent" atrial flutter. The goal of ablation is to produce bidirectional cavotricuspid isthmus block. Traditionally, this has been obtained by creation of a complete ablation line across the isthmus from the ventricular end to the inferior vena cava. This article describes an alternative method used in our laboratory. There is substantial evidence that conduction across the isthmus occurs preferentially over discrete separate bundles of tissue. Consequently, voltage-guided ablation targeting only these bundles with large amplitude atrial electrograms results in a highly efficient alternate method for the interruption of conduction across the cavotricuspid isthmus. Understanding the bundle structure of conduction over the isthmus facilitates more flexible approaches to its ablation and targeting maximum voltages in our hands has resulted in reduction of ablation time and fewer recurrences.

  11. Distance protection of multiple-circuit shared tower transmission lines with different voltages. Part I: Fault current magnitude

    DEFF Research Database (Denmark)

    Silva, Filipe Miguel Faria da; Bak, Claus Leth

    2017-01-01

    Multiple-circuit transmission lines combining different voltage levels in one tower present extra challenges when setting a protection philosophy, as faults between voltage levels are possible. This paper presents a detailed theoretical analysis of such combined faults, including the development...... of a formula for estimating the magnitude of the short-circuit current. It is demonstrated that if the faulted phase from the higher voltage level leads the faulted phase from the lower voltage level, a distance relay at the higher voltage level sees the fault in the forward direction, whereas a distance relay...... at the lower voltage level sees the fault in the reverse direction. The opposite happens if the lower voltage level leads the higher voltage level. It is also demonstrated that the magnitude of fault currents of combined faults is normally slightly larger than of equivalent single-phase-to-ground fault...

  12. Overhead Projector Demonstrations.

    Science.gov (United States)

    Kolb, Doris, Ed.

    1988-01-01

    Details two demonstrations for use with an overhead projector in a chemistry lecture. Includes "A Very Rapidly Growing Silicate Crystal" and "A Colorful Demonstration to Simulate Orbital Hybridization." The materials and directions for each demonstration are included as well as a brief explanation of the essential learning involved. (CW)

  13. Distance protection of multiple-circuit shared tower transmission lines with different voltages. Part II: Fault loop impedance

    DEFF Research Database (Denmark)

    Silva, Filipe Miguel Faria da; Bak, Claus Leth

    2017-01-01

    Multiple-circuit transmission lines combining different voltage levels in one tower present extra challenges when setting a protection philosophy, as faults between voltage levels are possible. In this paper, the fault loop impedance of combined faults is compared with the fault loop impedance...... of single-phase-to-ground faults at the higher voltage level of the multiple-circuit line and it is demonstrated that they are similar for high short-circuit powers; however, the fault loop impedance of a combined fault may increase substantially as the short-circuit power of the system decreases......-phase-to-ground faults are also capable of protecting the line against combined faults, being only advisable to increase the resistive limit of the protection zone if the network has lower short-circuit power. If the length of the line at lower voltage level is less than of the lien at higher voltage level...

  14. Residential Distance to High-voltage Power Lines and Risk of Neurodegenerative Diseases

    DEFF Research Database (Denmark)

    Frei, Patrizia; Poulsen, Aslak Harbo; Mezei, Gabor;

    2013-01-01

    period 5-20 years before diagnosis were computed. The risks for developing dementia, Parkinson's disease, multiple sclerosis, and motor neuron disease were not increased in persons living within close vicinity of a power line. The risk of Alzheimer's disease was not increased for ever living within 50 m......The aim of this study was to investigate the possible association between residential distance to high-voltage power lines and neurodegenerative diseases, especially Alzheimer's disease. A Swiss study previously found increased risk of Alzheimer's disease for people living within 50 m of a power...... line. A register-based case-control study including all patients diagnosed with neurodegenerative diseases during the years 1994-2010 was conducted among the entire adult population of Denmark. Using conditional logistic regression models, hazard ratios for ever living close to a power line in the time...

  15. 基于电容补偿无功电源的长距离架空输电线路融冰仿真实验和方案设计%De-icing scheme and experiment of long distance HV overhead power line based on capacitor compensating reactive current

    Institute of Scientific and Technical Information of China (English)

    刘刚; 赵学增; 王立辉; 彭辉; 卜劲松; 陈永辉; 姜世金; 梁岩; 刘子军

    2011-01-01

    长距离架空输电线路存在线路感抗随着线路长度的增加而增大的问题.采用在融冰线路中串联补偿电容器的方法来抵消融冰线路的感抗,以降低融冰线路的总阻抗,保证电容补偿无功电源融冰方法应用于长线路融冰,系统能够提供有效的融冰电流.针对电容补偿无功电源融冰方法存在的电容器端电压升高问题,提出提高电容器对地绝缘水平的方法和采用电容器多组串联分压的方式,用来解决在融冰过程中电容器过电压导致现有10 kV电容器额定电压无法满足融冰操作要求的问题.通过低电压模拟电路仿真实验,绘制出线路阻抗电压与末端电容器电压随着线路长度变化的向量关系图,并给出利用10 kV电源和10 kV电容器对220 kV输电线路LGJ400导线融冰的参数计算和具体实施融冰的方案.%The inductance of a long distance HV overhead power line increases with the extension of the line. In order to decrease the total impedance of the power line and ensure the system could provide effective de-icing current by using the de-icing method based on capacitor compensation reactive current, the measure of connecting series capacitor banks to the de-icing line for compensating the line inductance is applied. With the capacitor terminal voltage increment by using capacitor compensation de-icing method, a mean of improving the capacitor voltage insulation level to ground and series-mounting multi-group capacitor banks to the de-icing line for partial voltage are proposed to solve the problem that the rated voltage of existing 10 kV capacitor banks can not satisfy the operation requirements, which is caused by capacitor over-voltage during the de-icing process. The voltage vector relationship of capacitor and line impedance with the length of de-icing line variation is given based on the analog low voltage circuit simulation. Furthermore, the specified scheme and calculation for de-icing 220 k

  16. On-line Monitoring System based on Vibration Signal of High Voltage Circuit Breaker

    Directory of Open Access Journals (Sweden)

    Chao Fu

    2014-04-01

    Full Text Available High voltage circuit breaker is one of the most important switch apparatus in electrical power system. It play a role in the switch control, which can be used to switch the operating mode during normal operation (the equipment run or quit. In order to ensure the normal operation of the grid, it can be removed quickly when a malfunction on the device or circuit. Real-time online monitoring of high voltage circuit breaker can understand the running status, master the operation characteristics and its tend of development. As early as possible find the potential faults then take preventive measures timely, so as to ensure the reliable operation of power system. Online monitoring of high voltage circuit breakers can reduce the premature or unnecessary maintenance and maintenance cost, improve pertinence of the maintenance firstly. Secondly, it can improve the life of the switching device and improve the reliability of electric power system significantly. In this paper, on-line monitoring system based on vibration signal of high voltage circuit breaker is presented

  17. Increase in the scattering of electric field lines in a new high voltage SOI MESFET

    Science.gov (United States)

    Anvarifard, Mohammad K.

    2016-09-01

    This paper illustrates a new efficient technique to enhance the critical features of a silicon-on-insulator metal-semiconductor field-effect transistor (SOI MESFET) applied in high voltage applications. The structure we proposed utilizes a new method to scatter the electric field lines along the channel region. Realization of two trenches with different materials, which a trench is created in the channel region and the other one is created in the buried oxide, helps the proposed structure to improve the breakdown voltage, driving current, drain-source conductance, minimum noise figure, unilateral power gain and output power density. Exploring the obtained results, the proposed structure has superior electrical performance in comparison to the conventional structure.

  18. Fast Decoupled Power Flow for Power System with High Voltage Direct Current Transmission Line System

    Directory of Open Access Journals (Sweden)

    Prechanon Kumkratug

    2010-01-01

    Full Text Available Problem statement: High voltage direct current transmission line system has been widely applied for control power flow in power system. The power flow analysis was the one of powerful tools by which the power system equipped was analyzed both for planning and operation strategies. Approach: This study presented the method to analyze power flow of power system consisted of HVDC system. HVDC was modeled as the complex power injections. The presented complex power injected was incorporated into the existing power flow program based on fast decoupled method. The presented method was tested on the multimachine power system. Results: The transmission line loss of the system with and without HVDC was compared. Conclusion: From the simulation results, the HVDC can reduce transmission line loss of power system.

  19. Assumption or Fact? Line-to-Neutral Voltage Expression in an Unbalanced 3-Phase Circuit during Inverter Switching

    Science.gov (United States)

    Masrur, M. A.

    2009-01-01

    This paper discusses the situation in a 3-phase motor or any other 3-phase system operating under unbalanced operating conditions caused by an open fault in an inverter switch. A dc voltage source is assumed as the input to the inverter, and under faulty conditions of the inverter switch, the actual voltage applied between the line to neutral…

  20. Single-phased Fault Location on Transmission Lines Using Unsynchronized Voltages

    Directory of Open Access Journals (Sweden)

    ISTRATE, M.

    2009-10-01

    Full Text Available The increased accuracy into the fault's detection and location makes it easier for maintenance, this being the reason to develop new possibilities for a precise estimation of the fault location. In the field literature, many methods for fault location using voltages and currents measurements at one or both terminals of power grids' lines are presented. The double-end synchronized data algorithms are very precise, but the current transformers can limit the accuracy of these estimations. The paper presents an algorithm to estimate the location of the single-phased faults which uses only voltage measurements at both terminals of the transmission lines by eliminating the error due to current transformers and without introducing the restriction of perfect data synchronization. In such conditions, the algorithm can be used with the actual equipment of the most power grids, the installation of phasor measurement units with GPS system synchronized timer not being compulsory. Only the positive sequence of line parameters and sources are used, thus, eliminating the incertitude in zero sequence parameter estimation. The algorithm is tested using the results of EMTP-ATP simulations, after the validation of the ATP models on the basis of registered results in a real power grid.

  1. The commercial development of water repellent coatings for high voltage transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, S. R. [ORNL; Daniel, A. [Southwire Company

    2013-10-31

    The purpose of the Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC and Southwire Company was to jointly develop a low cost, commercially viable, water-repellant anti-icing coating system for high voltage transmission lines. Icing of power lines and other structures caused by freezing rain events occurs annually in the United States, and leads to severe and prolonged power outages. These outages cause untold economic and personal distress for many American families and businesses. Researchers at the Department of Energy?s Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee have previously developed a set of superhydrophobic coatings with remarkable anti-icing properties that could potentially be sprayed or painted onto high-tension power lines and pylons. These coatings drastically reduce ice accumulation on these structures during freezing rain events. The project involved obtaining technical input, supplies and test high voltage cables from Southwire, along with the joint development of anti-icing coating techniques, which would result in a commercial license agreement between Southwire and ORNL, and potentially other companies requiring water repellent anti-icing coatings.

  2. The commercial development of water repellent coatings for high voltage transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, Scott Robert [ORNL

    2013-10-01

    The purpose of the Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC and Southwire Company was to jointly develop a low cost, commercially viable, water-repellant anti-icing coating system for high voltage transmission lines. Icing of power lines and other structures caused by freezing rain events occurs annually in the United States, and leads to severe and prolonged power outages. These outages cause untold economic and personal distress for many American families and businesses. Researchers at the Department of Energy s Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee have previously developed a set of superhydrophobic coatings with remarkable anti-icing properties that could potentially be sprayed or painted onto high-tension power lines and pylons. These coatings drastically reduce ice accumulation on these structures during freezing rain events. The project involved obtaining technical input, supplies and test high voltage cables from Southwire, along with the joint development of anti-icing coating techniques, which would result in a commercial license agreement between Southwire and ORNL, and potentially other companies requiring water repellent anti-icing coatings.

  3. Experimental Study of Electromagnetic Environment in the Vicinity of High Voltage Lines

    Directory of Open Access Journals (Sweden)

    Wafa Tourab

    2011-01-01

    Full Text Available Problem statement: Several studies have investigated the impact of electromagnetic field generated by high voltage power lines on environment. The evaluation of electric and magnetic field quantities are of paramount interest in the characterization of electromagnetic environment of the proposed line. The purpose of this study was to analyze the behavior of electromagnetic fields generated by power lines in an area of strong population. Approach: The method applied in this study was gradual; examined the effects of different couplings between the different neighboring lines on behavior of electric and magnetic fields. Later, these lines will be used as a source of disturbance applied to the auditory implants EMC. Results: The implications of experimental results were also compared and discussed with new standard. Conclusion: The maximum intensities of electric and magnetic fields measured for the circuit of three lines close to each other, within the El-HADJAR substation were significantly lower than the ICNIRP reference levels for occupational and no occupational exposures.

  4. Measurement and Modeling of Personal Exposure to the Electric and Magnetic Fields in the Vicinity of High Voltage Power Lines

    OpenAIRE

    Tourab, Wafa; Babouri, Abdesselam

    2015-01-01

    Background This work presents an experimental and modeling study of the electromagnetic environment in the vicinity of a high voltage substation located in eastern Algeria (Annaba city) specified with a very high population density. The effects of electromagnetic fields emanating from the coupled multi-lines high voltage power systems (MLHV) on the health of the workers and people living in proximity of substations has been analyzed. Methods Experimental Measurements for the Multi-lines power...

  5. Effect of four factors in the calculation of induced voltages on a tree-shaped distribution line

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Horacio; Perez, Ernesto; Herrera, Javier; Younes, Camilo; Salgado, Milton; Quintana, Carlos; Rondon, Daniel; Gallego, Luis; Montana, Johny; Vargas, Mauricio [Universidad Nacional de Colombia, Bogota (Colombia). Research Program on Acquisition and Analysis of Signals - PAAS]. E-mail: paas@paas.unal.edu.co

    2001-07-01

    The main objective of this paper is to show a sensibility analysis of four different factors: current waveform, return stroke velocity, lightning current amplitude and network configuration in the calculation of induced voltages on a tree-shaped distribution line. In order to calculate distribution line. In order to calculate the induced voltages it was used the EMTP/ATP program with the inclusion of Rusck's Coupling Model into the MODELS routine. (author)

  6. Methodology for the assessment of the impact of existing high voltage lines in urban areas

    Energy Technology Data Exchange (ETDEWEB)

    Sumper, Andreas [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Departament d' Enginyeria Electrica, Universitat Politecnica de Catalunya, EU d' Enginyeria Tecnica Industrial de Barcelona, Comte d' Urgell, 187, 08036 Barcelona (Spain); Catalonia Institute for Energy Research (IREC) (Spain); Boix-Aragones, Oriol; Bergas-Jane, Joan [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Departament d' Enginyeria Electrica, Universitat Politecnica de Catalunya, ETS d' Enginyeria Industrial de Barcelona, Av. Diagonal, 647, Pl. 2. 08028 Barcelona (Spain); Villafafila-Robles, Roberto; Ramirez-Pisco, Rodrigo [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Departament d' Enginyeria Electrica, Universitat Politecnica de Catalunya, EU d' Enginyeria Tecnica Industrial de Barcelona, Comte d' Urgell, 187, 08036 Barcelona (Spain)

    2010-10-15

    This paper presents a methodology for the assessment of the impact of existing high voltage lines in urban areas. This methodology is based on the numeric evaluation of several impacts which are combined with weight factors. The novelty is that it opens up the possibility of citizen participation, basically in the way in which impacts and weighting factors are determined. The proposed methodology has been applied first in the municipality of Rubi, a mid-sized town near Barcelona, and later on in several municipalities in the Catalonia region in Spain. The results were used to prioritise mitigation action in the Catalonia Energy Plan. (author)

  7. Transmission delay and temperature variations in overhead optic links installed along distribution lines due to meteorological effects; Haidensen tenka hikari cable senro no denso chien to ondo no hendo tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Serizawa, Y.; Myosin, M.; Kitamura, K. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    1996-03-01

    Transmission delay and temperature variation characteristics in overhead fiber optic links were measured by the whole system time synchronous network evaluation test unit, to clarify the relation between the above and meteorological conditions. The transmission delay measured in the round-trip 25 km overhead links showed daily variations, which was the same as the OPGW (optical ground wire) line. As a result of the regression analysis using meteorological conditions, the transmission delay variation at 5:00 in early morning was greatly affected by the atmospheric temperature, and that at 13:00 in the daytime was affected greatly by the atmospheric temperature and the solar radiation. The coefficients of delay variation with respect to atmospheric temperature were 82 to 97 ps/km/{degree}C for a 48-core cable with 6-core optical fiber unit structure, and 70 to 84 ps/km/{degree}C for a 128-core cable using two-package-core cable. The coefficients depended greatly on the cable structure including OPGW. For the relation between the transmission delay and the mean temperature of cable in the total length, or meteorological conditions, the cable temperature rose more than 10{degree}C at maximum due to solar radiation. Increase of the cable temperature due to solar radiation could be easily estimated only from the atmospheric temperature and delay data. 9 refs., 13 figs.

  8. New Breed of Bipolar MMC-HVDC Topology for Overhead Line Transmission%适用于架空线路输电的新型双极MMC-HVDC拓扑

    Institute of Scientific and Technical Information of China (English)

    薛英林; 徐政

    2013-01-01

    在充分借鉴传统直流输电工程结线方式的基础上,提出了一种适用于架空线路输电的新型双极模块化多电平换流器型高压直流输电(MMC-HVDC)系统拓扑.该拓扑中换流器采用基于箝位双子模块的改进型模块化多电平换流器(MMC),接地极线从上下2个换流器串联构成的双极结构中间引出.重点分析了换流器在故障条件下的等值电路和直流闭锁机理,并设计了直流侧故障后的详细控制策略,并用PSCAD/EMTDC仿真软件验证了该系统拓扑的有效性和可行性.结果表明:双极拓扑具有运行方式灵活、系统可靠性高等优点;由于二极管反向阻断和箝位作用,换流器在封锁所有绝缘栅双极型晶体管(IGBT)触发脉冲后数ms内就能实现直流闭锁,因此无需交流断路器动作,仅依靠换流器自身动作就能抑制短路电流;所设计的控制时序可有效处理直流侧的故障,并在暂时性故障下帮助系统迅速重启动,减少系统停运时间.%We propose a new type of bipolar MMC-HVDC topology for overhead line transmission by referencing the traditional HVDC system topology. This topology adopts improved modular multilevel converters (MMC) based on clamp double sub-modules. The ground electrode is led from the junction center of the bipolar structure, which consists of up-and-down converters in series. Furthermore, the equivalent circuit during DC fault and the fault blocking mechanism are analyzed, a control strategy and action sequence of the converter under the DC fault is proposed, and the feasibility and validity of the bipolar system are verified by PSCAD/EMTDC simulations. Several results are obtained from the simulation; the bipolar topology offers many features such as flexible operation modes and high system reliability, etc. ; Owing to reverse blocking and voltage clamping of diodes, the DC blocking capability is achieved within a few milliseconds after turning off all insulated gate

  9. Snow accretion on overhead wires

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Y. [Meteorological Research Inst. for Technology Co. Ltd., Tokyo (Japan); Tachizaki, S.; Sudo, N. [Tohoku Electric Power Co. Ltd., Miyagi (Japan)

    2005-07-01

    Wet snow accretion can cause extensive damage to transmission systems. This paper reviewed some of the difficulties faced by researchers in the study of wet snow accretion on overhead lines in Japan. The study of snow accretion phenomena is complicated by the range of phase changes in water. Snowflakes produced in an upper atmospheric layer with a temperature below freezing do not melt when they go through a lower atmospheric layer with a temperature above freezing, but are in a mixed state of solid and liquid due to the latent heat of melting. The complicated properties of water make studies of snow accretion difficult, as well as the fact that snow changes its physical properties rapidly, due to the effects of ambient temperature, rainfall, and solar radiation. The adhesive forces that cause snow accretion include freezing; bonding through freezing; sintering; condensation and freezing of vapor in the air; mechanical intertwining of snowflakes; capillary action due to liquids; coherent forces between ice particles and water formed through the metamorphosis of snowflakes. In addition to these complexities, differences in laboratory room environments and natural snow environments can also pose difficulties for researchers. Equations describing the relationship between the density of accreted snow and the meteorological parameters involved were presented, as well as empirical equations which suggested that snow accretion efficiency has a dependency on air temperature. An empirical model for estimating snow loads in Japan was outlined, as well as various experiments observing show shedding. Correlations for wet snow accretion included precipitation intensity; duration of precipitation; air temperature; wind speed and wind direction in relation to the overhead line. Issues concerning topography and wet snow accretion were reviewed. It was concluded that studies of snow accretion will benefit by the collection of data in each matrix of the relevant parameters. 12 refs

  10. Lightning-induced overvoltages in low-voltage systems

    Energy Technology Data Exchange (ETDEWEB)

    Hoeidalen, Hans Kristian

    1997-12-31

    Lightning-induced overvoltages (LIOs) are a main source of failures in low-voltage overhead line systems. This thesis deals mainly with calculations of LIOs aiming to enable the design of a proper voltage protection. Models for calculation of LIOs are adapted from the literature or developed based on measurements. The models used are believed to be fairly accurate for the first few microseconds, which is usually sufficient for predicting the maximum induced voltage in the system. The lightning channel is modelled by the Modified Transmission Line (MTL) model with the Transmission Line (TL) model as a special case. The coupling between the electrical fields from a lightning channel and an overhead line is modelled by Agrawal`s model. The attenuation of electrical fields over a lossy ground is modelled by Norton`s- or the Surface Impedance methods. The validity of all the applied models is analysed. In addition, measurements have been performed in order to develop models of distribution transformers and low-voltage power installation (LVPI) networks. Simple models of typical transformers and LVPIs are developed for calculations when specific data are unavailable. The practical range of values and its influence on the LIOs in a system is investigated. The main frequency range of interest related to LIOs is 10 kHz - 1 MHz in which all the models are accurate. The adapted or developed models are used to calculate LIOs in low-voltage systems. The influence of various key parameters in the system is investigated. Most important are the return stroke amplitude and rise time, the overhead line height and location, the termination of overhead line segments, neutral grounding, and the ground conductivity. 135 refs., 136 figs., 12 tabs.

  11. Apparatus and Method for Compensating for Process, Voltage, and Temperature Variation of the Time Delay of a Digital Delay Line

    Science.gov (United States)

    Seefeldt, James (Inventor); Feng, Xiaoxin (Inventor); Roper, Weston (Inventor)

    2013-01-01

    A process, voltage, and temperature (PVT) compensation circuit and a method of continuously generating a delay measure are provided. The compensation circuit includes two delay lines, each delay line providing a delay output. The two delay lines may each include a number of delay elements, which in turn may include one or more current-starved inverters. The number of delay lines may differ between the two delay lines. The delay outputs are provided to a combining circuit that determines an offset pulse based on the two delay outputs and then averages the voltage of the offset pulse to determine a delay measure. The delay measure may be one or more currents or voltages indicating an amount of PVT compensation to apply to input or output signals of an application circuit, such as a memory-bus driver, dynamic random access memory (DRAM), a synchronous DRAM, a processor or other clocked circuit.

  12. Calculation Model for the Propagation of Audible Noise from High Voltage Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    LI Xuebao; CUI Xiang; LU Tiebing; HE Jiamei

    2013-01-01

    Audible noise from high voltage transmission lines' corona discharge has become one of the decisive factors affecting design of high voltage transmission lines,thus it is very important to study the spatial propagation characteristics of audible noise for its accurate prediction.A calculation model for the propagation of audible noise is presented in this paper,which is based on the basic equation of the sound wave and can involve the influences of the atmosphere absorption and ground effects.The effects of different ground impedances and the atmospheric attenuation on the distribution of sound pressure level are discussed in this paper.The results show that the atmospheric absorption may increase the attenuation of the audible noise,and the ground surface affects both the amplitude and phase of the sound.The spatial distribution fluctuates considering the ground effects.The atmospheric attenuation and the ground effect are closely related to the frequency of the noise.In the frequency range of the audible noise,the influence of atmospheric attenuation on the spatial propagation characteristics is more obvious in high frequency while ground has significant influences in low frequency.

  13. Simulation of a Narrowband Power Line Communications System over Medium Voltage

    Directory of Open Access Journals (Sweden)

    Nikolaos Chiotellis

    2016-03-01

    Full Text Available Narrowband Power Line Communications (NB-PLCs are investigated as an alternative option for transferring low rate smart grid (SG data via Medium Voltage (MV power lines. In this framework, two variants of orthogonal frequency division multiplexing are examined, namely Filtered-OFDM (F-OFDM and Wavelet-OFDM (W-OFDM, in an attempt to determine which of them is capable of transmitting low rate SG data to greater distances over non-branched MV power lines. The reach of NB-PLC signals via MV power lines is estimated, taking into account the transfer function of the relevant PLC channels and noise mechanisms as well as the specific features of the two modulation options under consideration. Simulations show that NB-PLC transmission constitutes a technically feasible and economically affordable option for exchanging low rate data with remote SG nodes dispersed over the MV grid. Moreover, simulations show that F-OFDM allows low rate data transmission to considerably greater distances compared to W-OFDM.

  14. THE NO SINUSOIDAL VOLTAGES UNDER THE SINUSOIDAL CURRENT AT THE ENTRY OF THE OPEN–ENDED LINE WITH REAL LOSS

    Directory of Open Access Journals (Sweden)

    Patsiuk V.I.

    2008-12-01

    Full Text Available he classical problems of the theoretical electrical engineering, such as open-ended (or short-circuited line energization on alternating voltage (or current, are solved by means of Fourier series method. The conditions of creation of no sinusoidal steady-state regimes in the lines with nonzero loss are discovered.

  15. 电力建设中架空输配电线路的设计及施工%Design and Construction of Electric Power Construction of Overhead Transmission and Distribution Lines

    Institute of Scientific and Technical Information of China (English)

    钟沃波

    2016-01-01

    The socio-economic level of continuous improvement,and promote the further development of the power industry, and in recent years,China’s comprehensive national strength continued to improve,the population also increase,and the amount of people on the electricity supply and demand is increasing,then power construction engineering quality It is very important.The impact of power construction projects in overhead transmission and distribution lines throughout the design and construction of power engineering quality is great,this paper discusses the construction of overhead electric power transmission and distribution line design and construction,and practicality of proposed measures apply for the power construction enhance the level to provide a reference.%社会经济水平的不断提升,推动了电力行业的进一步发展,且近年来我国综合国力持续增强,人口数量亦随之增多,人们对电量的供求量不断增加,这时电力建设工程质量十分重要。而电力建设工程中的架空输配电线路设计与施工对整个电力工程质量影响极大,探讨了电力建设中架空输配电线路设计与施工,并提出了实用性应用措施,为电力建设工程水平提升提供参考依据。

  16. 四分裂架空输电线路导线接续管的更换工艺%Replacement Technology for Conductor Connecting Pipe of Quad-bundle Overhead Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    朱迪锋

    2016-01-01

    This paper describes the characteristics of replacement technology at height for conductor connect-ing pipe of quad-bundle EHV overhead transmission lines; besides, it analyzes the construction technology process. The construction technology is adopted in practical maintenance work, after which construction effi-ciency is enhanced, outage time of power lines is shortened, manpower and material resources for construc-tion work are reduced;besides, the impact on objects below the lines is reduced, and safety and efficiency of EHV transmission line maintenance are guaranteed.%叙述了四分裂超高压架空输电线路导线接续管的高空更换施工工艺特点,分析该施工工艺流程。在实际检修工作中运用后有效提高了施工效率,缩短线路停电时间,减少施工所需人力物力的投入,并对线路下方影响大大减少,确保了超高压输电线路检修工作的安全高效进行。

  17. MODELING OF OVERHEAD TRANSMISSION LINES FOR LIGHTNING OVERVOLTAGE CALCULATIONS MODELACIÓN DE LÍNEAS AÉREAS DE TRANSMISIÓN PARA EL CÁLCULO DE SOBRETENSIONES ORIGINADAS POR EL RAYO

    Directory of Open Access Journals (Sweden)

    Juan A Martínez-Velasco

    2010-04-01

    Full Text Available Several parts of an overhead transmission line have to be included in a model adequate for lightning overvoltage studies: wires (shield wires and phase conductors, towers, grounding, insulator strings and air clearances. An additional component, the surge arrester, should be added if the study is aimed at determining the lightning performance of a transmission line protected by surge arresters. This latter aspect is important since it can affect the model to be used for representing some parts of the line. Lightning is a physical phenomenon of random nature. The calculation of the lightning flashover rate must be performed taking into account this aspect, as well as the random behavior of some line component; e.g., insulator strings. The aim of this paper is twofold: on one hand, it presents a discussion about modeling guidelines proposed to date for representing overhead transmission lines in lightning studies; on the other hand, it proposes a methodology for selecting the most adequate model of an overhead transmission line in lightning overvoltage calculations, when using a time-domain simulation tool, e.g. an EMTP-like tool. This methodology is applied to a test transmission line.Un modelo de línea aérea de transmisión adecuado para el cálculo de sobretensiones originadas por el rayo debe incluir varias partes de la línea: conductores de fase y cables de guarda, torres, puestas a tierra, cadenas de aisladores y distancias en el aire. Un componente adicional, el pararrayos, puede ser necesario si el estudio tiene como objetivo evaluar el comportamiento frente al rayo de una línea de transmisión protegida mediante pararrayos. Este último aspecto es importante ya que el modelo a utilizar puede variar según se hayan instalado o no pararrayos para proteger la línea. El rayo es un fenómeno físico de naturaleza aleatoria. El cálculo de la tasa de contorneos (flameos causados por descargas atmosféricas ha de realizarse teniendo en

  18. Environmental justice: a contrary finding for the case of high-voltage electric power transmission lines.

    Science.gov (United States)

    Wartenberg, Daniel; Greenberg, Michael R; Harris, Gerald

    2010-05-01

    Environmental justice is the consideration of whether minority and/or lower-income residents in a geographic area are likely to have disproportionately higher exposures to environmental toxins than those living elsewhere. Such situations have been identified for a variety of factors, such as air pollution, hazardous waste, water quality, noise, residential crowding, and housing quality. This study investigates the application of this concept to high-voltage electric power transmission lines (HVTL), which some perceive as a health risk because of the magnetic fields they generate, and also as esthetically unpleasing. We mapped all 345 kV and higher voltage HVTL in New York State and extracted and summarized proximate US Census sociodemographic and housing characteristic data into four categories on the basis of distances from HVTL. Contrary to our expectation, people living within 2000 ft from HVTL were more likely to be exposed to magnetic fields, white, of higher income, more educated and home owners, than those living farther away, particularly in urban areas. Possible explanations for these patterns include the desire for the open space created by the rights-of-way, the preference for new homes/subdivisions that are often located near HVTL, and moving closer to HVTL before EMFs were considered a risk. This study suggests that environmental justice may not apply to all environmental risk factors and that one must be cautious in generalizing. In addition, it shows the utility of geographical information system methodology for summarizing information from extremely large populations, often a challenge in epidemiology.

  19. Construction Method of Uninterruptible Power Crossing 1 0 kV Overhead Lines%一种不停电跨越10 kV架空线路的施工方法

    Institute of Scientific and Technical Information of China (English)

    黄顺涛; 陈文军

    2015-01-01

    Two-time power cut is required for traditional construction of crossing electric power lines. In order to improve power supply reliability,a kind of construction method of uninterruptible power disassembling 1 0 kV overhead lines was pro-posed. By means of coil typed insulating sheaths,the overhead lines were isolated and nesting between insulating sheath and lines was realized in a way of occlusion of interfaces of insulation buckles. New type high polymer materials were used to make insulating sheaths for improving toughness and scroll wheel occlusal assistant devices were used for installing the insula-ting sheaths so as to reduce wearing and labor intensity. This construction method was applied in six power transmission and transformation projects of Zhuhai Power Supply Bureau of Guangdong Power Grid Co.,Ltd. which could complete con-struction of lines crossing in uninterruptible power state and reduce 4 932 households as power cut. Meanwhile,it could avoid industry and agriculture losses of 6 636 300~8 295 400 yuan which might bring about obvious social and economic benefits.%传统的跨越电力线路施工方法需对用户停电2次,为提高供电可靠性,提出一种不停电装拆10 kV 架空线路跨越架的施工方法。该施工方法通过盘卷式绝缘护套隔离架空线路,并以卡扣接口咬合方式实现绝缘护套与线路的嵌套,采用新型高分子材料制作绝缘护套以提高韧性,利用滚轮咬合辅助器装设绝缘护套以降低磨损和劳动强度。该施工方法在广东电网有限责任公司珠海供电局的6个输变电工程中应用,均可完成不停电状态下的线路跨越施工,共减少停电时户数4932,避免了663.63~829.54万元的工农业经济损失,社会效益和经济效益显著。

  20. Transient Recovery Voltages at the Main 132kV Line Bay GIS Circuit Breaker in a Windfarm

    OpenAIRE

    Arana Aristi, Iván; Okholm, J.; Holbøll, Joachim

    2011-01-01

    This paper presents the results of investigations of the Transient Recovery Voltage (TRV) across the terminals of the main 132kV Line Bay GIS circuit breaker (GIS CB) for Walney 2, second phase of the Walney Offshore Wind Farm. Several simulations were performed where the influence of different parameters in the network was evaluated during a fault in the onshore substation. The rate of rise of recovery voltage (RRRV) and the maximum crest voltage (Uc) of the TRV across the GIS CB were compar...

  1. Efectos de las Ramificaciones y de los Edificios en los Voltajes Inducidos por Rayos en Líneas de Distribución Urbanas The Effects of Line Laterals and Nearby Buildings on Lightning-Induced Voltages in Urban Distribution Lines

    Directory of Open Access Journals (Sweden)

    A. Piantini

    2004-01-01

    Full Text Available Se presentan algunos resultados experimentales, de los efectos de las ramificaciones y de los edificios cercanos, en los voltajes inducidos por rayos en líneas de distribución urbanas. Usando un modelo en escala reducida de 1:50, las pruebas fueron realizadas considerando una típica configuración de línea de distribución, incluyendo la simulación del conductor neutral, ramificaciones, edificios y equipos como los pararrayos y transformadores. Se presentan comparaciones entre voltajes inducidos en los terminales de alto voltaje del transformador para diferentes alturas de los edificios y situaciones del transformador. Los resultados muestran que en algunas circunstancias las ramificaciones y la presencia de estructuras cercanas a la línea pueden afectar significativamente los voltajes inducidos por descargas atmosféricasSome experimental results are presented from research on the effects of laterals and nearby buildings on the lightning-induced voltages in urban overhead distribution lines. By making use of a 1:50 scale model, tests were performed considering a typical distribution line configuration, including the simulation of the neutral conductor, laterals, buildings, and equipment such as arresters and transformers. Comparisons between voltages induced at the HV transformer terminals are presented for different building heights and transformer locations. The results show that in some circumstances the laterals and the presence of structures close to the lines may significantly affect the induced voltages

  2. A Novel High-Frequency Voltage Standing-Wave Ratio-Based Grounding Electrode Line Fault Supervision in Ultra-High Voltage DC Transmission Systems

    Directory of Open Access Journals (Sweden)

    Yufei Teng

    2017-03-01

    Full Text Available In order to improve the fault monitoring performance of grounding electrode lines in ultra-high voltage DC (UHVDC transmission systems, a novel fault monitoring approach based on the high-frequency voltage standing-wave ratio (VSWR is proposed in this paper. The VSWR is defined considering a lossless transmission line, and the characteristics of the VSWR under different conditions are analyzed. It is shown that the VSWR equals 1 when the terminal resistance completely matches the characteristic impedance of the line, and when a short circuit fault occurs on the grounding electrode line, the VSWR will be greater than 1. The VSWR will approach positive infinity under metallic earth fault conditions, whereas the VSWR in non-metallic earth faults will be smaller. Based on these analytical results, a fault supervision criterion is formulated. The effectiveness of the proposed VSWR-based fault supervision technique is verified with a typical UHVDC project established in Power Systems Computer Aided Design/Electromagnetic Transients including DC(PSCAD/EMTDC. Simulation results indicate that the proposed strategy can reliably identify the grounding electrode line fault and has strong anti-fault resistance capability.

  3. Inspection Technology for Channel Environment of Overhead Transmission Line and Its Application%架空输电线路通道环境的巡视技术与应用

    Institute of Scientific and Technical Information of China (English)

    邓元婧; 汪从敏; 夏开全; 江炯; 张浩

    2014-01-01

    输电线路通道环境的巡视效率和质量直接关系电网的安全可靠运行。综述了目前3种巡视模式及其特点,分析了每种模式下所使用的主要巡视技术,并提出在直升机、无人机与人工协同巡检模式下,应结合在线监测系统开展进一步研究,以实现输电网络线路资料的数字化与可视化,从而对输电线路状态评价提供数据支撑和决策建议,推进输电线路状态巡视,提升输电线路运维管理水平。%The inspection efficiency and quality of channel environment of overhead transmission line are di-rectly related to the safe and reliable operation of power grid. This paper comprehensively expounds three pre-sent line inspection modes and their characteristics, and it analyzes main inspection technologies employed in each mode. Additionally, it suggests that further research should be conducted by combining online monitor-ing system under helicopter and unmanned aircraft inspection partnered with manual inspection to fulfill the digitization and visualization of the line information of power transmission networks , and thereby offers data support and decision-making suggestions for state assessment of power transmission line , promoting condition-based inspection of power transmission line as well as improving operation and maintenance management level of power transmission line.

  4. 架空线路载流量的导线温度测量方法研究%Method of Measuring Conductor Temperature for Ampacity of Overhead Lines

    Institute of Scientific and Technical Information of China (English)

    刘刚; 林杰; 陈荣锋; 张鸣

    2013-01-01

    The dynamic ampacity of overhead transmission lines can be calculated by the formula of IEEE 738-2006 standard. However,a larger error occurs as a result of using the surface temperature of wire instead of the actual wire temperature when calculating the ampacity. In order to measure the real temperature of overhead conductor, the paper explores a suitable temperature measurement through the further study about the temperature of different locations in the same section of the conductor. The method about using the aluminum layer to cover thermal resistance solves the problem about the differences between the surface temperature of wire and its actual temperature. The experimental results show that the error between the measured value and the real wire temperature is less than 1.5℃.%  架空输电线路动态载流量可以通过IEEE738-2006标准提供的公式进行计算,但在采用导线表面温度代替导线实际温度来计算导线载流量时会产生较大的误差。为了更准确地测量架空导线温度,通过对导线同一截面不同位置的温度深入研究,探究架空导线合适的测温方法。提出利用铝层包裹热电阻传感器探头的测温方法,解决导线表面温度与实际温度之间的差值问题。通过实验证明,测量值与导线真实温度误差在1.5℃以内。

  5. Development Ground Fault Detecting System for D.C Voltage Line

    Energy Technology Data Exchange (ETDEWEB)

    Kim Taek Soo; Song Ung Il; Gwon, Young Dong; Lee Hyoung Kee [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1996-12-31

    It is necessary to keep the security of reliability and to maximize the efficiency of maintenance by prompt detection of a D.C feeder ground fault point at the built ed or a building power plants. At present, the most of the power plants are set up the ground fault indicator lamp in the monitor room. If a ground fault occurs on DC voltage feeder, a current through the ground fault relay is adjusted and the lamps have brightened while the current flows the relay coil. In order to develop such a system, it is analyzed a D.C feeder ground circuit theoretically and studied a principles which can determine ground fault point or a polarity discrimination and a phase discrimination of the line. So, the developed system through this principles can compute a resistance ground fault current and a capacitive ground fault current. It shows that the system can defect a ground fault point or a bad insulated line by measuring a power plant D.C feeder insulation resistance at the un interruptible power status, and therefore the power plant could protect an unexpected service interruption . (author). 18 refs., figs.

  6. 用于架空输电线的不同耐热导线的比较分析%Comparative Analysis on Different Heat-Resistant Conductors Used for Overhead Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    刘俊勇; 罗文

    2011-01-01

    简述了国内外耐热导线在架空输电工程中的应用、技术发展水平和目前国内的需求状况,介绍了耐热导线的种类、结构和性能特点,对比分析了不同耐热导线在金具使用、工程造价和线损等方面的差异,为耐热导线设计选型提供参考.%This paper overviewed the application of the heat -resistant conductor used in overhead transmission lines both at home and ahroad, the latest development of the technology, and the present domestic demand for the type of conductors. It also introduced the types, structures and performance characteristics of the conductor, compared and analyzed differences among heat -resistant conductors of different types in terms of the use of fittings, project cost, and the line loss. The paper can provide some useful references for the selection and deign of heat-resistant conductors.

  7. Relation between the isokeraunic level and occurrence frequency of lightning flashes to overhead transmission lines; Chiiki no nenkan kaminari nissu to sodensen ni taisuru raigeki hindo

    Energy Technology Data Exchange (ETDEWEB)

    Udo, T.

    1998-09-01

    In Japan, mean annual days of thunderstorm activity (Td) is determined based on the observation of 10 years from 1954 to 1963, for each rectangular area of about 23 km times 27 km. The Td may change depending on the long term variation of climate. In addition, only one Td for a 23 km times 27 km area is not enough to express the locality of lightning activities. On the other hand, based on the analysis of lightning current measurement on 15 transmission lines in Japan, the author found that the content (%) of large current lightnings (such as larger than 80kA) is very larger in heavy lightning districts than in mild lightning districts. Taking the above phenomenon into account, and based on the statistical analysis of field investigation data, the author set up a new theory to estimate the lightning performance of transmission lines. 9 refs., 5 figs., 1 tab.

  8. 架空输电线路除冰技术分析%Analysis of Deicing Methods for Overhead Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    刘顺新; 罗浩东; 邓小磊

    2011-01-01

    At present, how to melt the ice on transmission lines to reduce the losses is still a worldwide technical problem. The existing deicing methods can be divided into three kinds, i.e. the ice-melting method, the mechanical deicing method, and the deicing method with new technology. In this study, a simple transmission line model was established, and the deicing methods mentioned above with their implementation circuits were analyzed respectively. Their advantages and disadvantages were compared.Thus, the most suitable deicing method for the transmission line model was obtained.%如何对覆冰输电线路进行融冰、除冰以降低冰灾损失,目前仍是世界性的技术难题.针对该问题,笔者在现有除冰技术如热力除冰法、机械除冰法以及其它新技术除冰法的基础上,建立了一个简单的输电线路模型,并依次研究各种除冰技术及其实现电路.最后得出适合该输电线路的除冰措施,从而为输电线路在覆冰情况下的除冰提供技术指导.

  9. 架空输电线路无人机人工联合巡检模式初探%A preliminary study on the artificial joint inspection mode for overhead transmission line

    Institute of Scientific and Technical Information of China (English)

    何健; 罗昳昀; 范畅; 侯品

    2015-01-01

    本文就架空输电线路无人机人工联合巡检进行了探讨性研究,首先介绍了此项研究的背景和意义,然后分析了输电线路无人机人工联合巡检工作存在的困难和问题,接着就无人机人工联合巡检工作如何更加深入地开展,提出了对策和建议.最后,提出输电线路无人机人工联合巡检目前还在探索实践阶段,需要通过不断改进,从而进一步提高输电线路无人机人工联合巡检的工作质效和应用范围.%In this paper,overhead transmission lines UAV artificial joint inspection conducted exploratory research,first introduced the background and significance of the study,and then analyzes the difficulties transmission line work drone artificial joint patrol presence and problem,then how artificial joint patrol drones to carry out more in-depth work,we put forward countermeasures and suggestions.Finally,the proposed transmission line drones artificial joint patrol is still in the stage of exploration and practice,through continuous improvement to further improve transmission line work drone artificial joint inspection of quality and efficiency and range of applications.

  10. Transient Fault Locating Method Based on Line Voltage and Zero-mode Current in Non-solidly Earthed Network

    Institute of Scientific and Technical Information of China (English)

    ZHANG Linli; XU Bingyin; XUE Yongduan; GAO Houlei

    2012-01-01

    Non-solidly earthed systems are widely used for middle voltage distribution network at home and abroad. Fault point location especially the single phase-to-earth fault is very difficult because the fault current is very weak and the fault arc is intermittent. Although several methods have been developed, the problem of fault location has not yet been resolved very well. A new fault location method based on transient component of line voltage and 0-mode current is presented in this paper, which can realize fault section location by the feeder automation (FA) system. Line voltage signal can be obtained conveniently without requiring any additional equipment. This method is based on transient information, not affected by arc suppression coil.

  11. Danger: electric shock. Overhead power line masts as the cause of death of large birds; Vorsicht: Stromschlag. Strommasten als Todesursache fuer bedrohte Grossvoegel

    Energy Technology Data Exchange (ETDEWEB)

    Aebischer, A.; Heynen, D.

    2007-07-01

    This short article takes a look at the masts of power lines running at 1 kV to 36 kV that pose a great danger for large birds. For white storks and owls, electric shock is the most frequent cause of death. The types of mast and the fittings which are particularly dangerous for these large birds are described. The effects noted on their population are discussed. Simple measures that can be taken to prevent theses deaths are looked at, including simple ones such the insulation of the wires near to the masts.

  12. THE SYSTEM OF CONTACT SYSTEM POWER SUPPLY OF DC NETWORK WITH A LONGITUDINAL LINE OF HIGH VOLTAGE

    Directory of Open Access Journals (Sweden)

    Yu. P. Honcharov

    2008-02-01

    Full Text Available The power supply system of a contact network using a longitudinal line with points of communication without transformer is considered. The approach allowing to facilitate power filters and the way of switching of in-series connected semiconductor switches with fixing a voltage on them are offered.

  13. 接触网V形天窗停电作业感应电压分析与触电预防%Analysis on the Induced Voltage in Power Cut Operation of Overhead Contact System’s V-Shaped Skylight

    Institute of Scientific and Technical Information of China (English)

    李惠杰

    2014-01-01

    This paper analyzes the induced voltage of V-shaped skylight of overhead contact system in China’s double electrified railway sections in power cut operation influencing the operation safety, explains that the induced voltage in the operation on V-shaped skylight will probably pose a threat to the personal safety of maintenance personnel, and puts forward some feasible measures for preventing the electric shock caused by the induced voltage, providing the reference for the safe operation and maintenance of tractive power supply system.%对我国双线电气化铁道区段接触网V形天窗停电作业中影响作业安全的感应电压进行了分析,说明在V形天窗作业时感应电压对检修人员的人身安全构成威胁,提出了可行的预防感应电压触电事故的措施,为牵引供电系统安全运行和维护提供了借鉴。

  14. Trends of high-voltage technology at the CIGRE 2002; Trends der Hochspannungstechnik: Berichte von der CIGRE 2002

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, T.; Degen, W.; Eckholz, K.; Glaunsinger, W.; Hussels, D.; Kirchesch, P.; Kirchner, M.; Lips, P.; Schwinne, M.; Slupinski, A.

    2002-12-01

    Meeting with the following topics: Study Committees, Rotating Electrical Machines, Transformers, High Voltage Equipment, Insulated Cables, Overhead Lines, Substations, HVDC and Power Electronics, Protections and Automations, System Development and Economics, System Control and Operation, System Environmental Performance, System Technical Performance, Electricity Markets and Regulation, Distribution Systems and Dispersed Generation, Materials and Emerging Technologies, Information Systems and Telecommunications. (orig.)

  15. Study on the Overhead Transmission Line with High Tower Across Forest%架空输电线路高塔跨越森林的研究

    Institute of Scientific and Technical Information of China (English)

    郑维权

    2011-01-01

    从钢管构件受力分析与实例验证两方面,研究钢管塔的优越性及其在跨越森林地区应用的可行性.结论为:500kV输电线路,由于其荷载较大,跨越森林地区使用钢管塔具有明显的优势;塔型对比分析显示,质量超过20 t的角钢塔使用钢管时,其质量可减少20%~35%,造价明显降低;钢管塔占地面积小,在选择塔位时具有优势.%In terms of stress analysis of steel components and examples, this paper studys the superiority and the application of steel towers across the forest areas. Conclusion: 500 kV transmission lines, due to its larger load, using steel towers across the forest areas has obvious advantages; tower comparative analysis shows that the weight of more than 200 kN of angle steel tower reduced 20% to 35% when used the steel components, and the cost significantly reduced; steel tower footprint is small, the advantage is seen when choose the tower position.

  16. Technology Research and Application of Video Information Analysis to Aerial Detection Overhead Transmission Line%架空输电线路航检视频信息分析技术研究与应用

    Institute of Scientific and Technical Information of China (English)

    关鑫; 毛鹏飞; 丁磊

    2015-01-01

    针对架空输电线路直升机巡检作业过程中航检员出现的塔号记录错误、影像资料不全、防鸟设施未作统计和缺陷遗漏等问题,采用了航检视频信息分析技术,对航检员所录制的高清航检视频进行分析整理,按照固定模式、顺序对线路通道、导线、杆塔连接金具挂点等重点部位进行截图编号分析,对输电线路存在的安全隐患问题进行检查,并建立输电线路航检视频分析数据库。该项技术的应用解决了航检员航检过程中塔号记录错误和一般缺陷遗漏的问题,提高了直升机巡检效率、质量和准确性,实现了对输电线路通道内情况、铁塔防鸟设施、防雷设施等数据统计,为输电线路运行、维护和管理提供依据。%The tower number recording error, the imperfect image data, and the uncluded anti-bird facilities occured during the process of aerial detection overhead transmission line. Use video information analysis technology to sort out high definition video recorded by the infrared video navigation inspectors, make an analysis of screen capture and numbering on the important parts of the fixed mode, order on line channel, wire, and tower connection hardware hanging point, check over the risks existed on the transmission line, and establish the video analysis database of transmission line aerial detection. The technology solves the problems of recording error and the general defect missing during the process of aerial detection, improves the efficiency, the quality and the accuracy of aerial detection, realizes the data statistics of transmission line channel condition, the bird-proof installations on the tower, and lightning protection facilities, which provides the theoretical foundition for the power transmission line operation, maintenance and management.

  17. Analysis on One Typical Span Jumper Connection Mode of 220 kV Overhead Lines%一例典型的220 kV 架空线路档中跳接方式分析

    Institute of Scientific and Technical Information of China (English)

    刘俊勇; 徐迎

    2016-01-01

    In allusion to one typical span jumper connection of 220 kV overhead lines,tension tower jumper connection is used for quickening engineering construction progress and saving cost. Calculation on mechanics,electrical engineering and lightning protection is conducted for this kind of jumper connection mode,and results indicate that the jumper connection conductor would not damage conductors and towers of original running lines,connection of amour clamps may satisfy re-quirement for current transmission of lines and the jumper connection line lies in the range of lightning protection. It is pointed out that measures such as using all aluminium conductor (AAC)or releasing conductor tension may effectively pro-tect original conductors,and it is able to improve lightning protection effect by using two lightning conductors combining with lightning protection mode. Temperature monitoring is carried out after lines running one month and results show lines are innormal states.%针对一例典型的220 kV 架空线路档中跳接工程,为加快工程建设进度和节约成本,采用非耐张塔跳接方式。对这种跳接方式进行力学、电气和防雷计算,结果表明:跳接导线不会损坏原运行线路的导线和杆塔,连接金具可满足线路输送电流的要求,跳接线路处于避雷保护范围。指出施工中采用铝绞线、放松导线张力等措施可有效保护原导线,采用2根避雷线联合避雷方式可提高防雷效果。线路运行1个月后进行温度监测,结果显示线路处于正常运行状态。

  18. A new model for induced voltage calculations in power transmission lines; Novo modelo para calculo de tensao induzida em LT's

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Fernando Henrique; Schroeder, Marco Aurelio de O.; Visacro Filho, Silverio; Soares Junior, Amilton [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Lightning Research Center - Nucleo de Desenvolvimento Cientifico e Tecnologico em Descargas Atmosfericas]. E-mail: lrc@cpdee.ufmg.br

    2001-07-01

    In this document the authors present the previous results of accomplished simulations through a brand new model to calculate the induced voltage by atmospheric discharges on power transmission lines. Through geometric data variation from the transmission line and discharge parameters, it is executed a sensibility analysis concerning to the relevant factors in order to define the levels of induced voltage in the transmission line. Finally, the work aims to evaluate this phenomenon importance in connection with 138 kv transmission lines.

  19. The monitoring results of electromagnetic radiation of 110-kV high-voltage lines in one urban location in Chongqing P.R. China.

    Science.gov (United States)

    Qin, Qi-Zhong; Chen, Yu; Fu, Ting-Ting; Ding, Li; Han, Ling-Li; Li, Jian-Chao

    2012-03-01

    To understand electromagnetic radiation field strength and its influencing factors of certain 110-kV high-voltage lines in one urban area of Chongqing by measuring 110-kV high-voltage line's electromagnetic radiation level. According to the methodology as determined by the National Hygienic Standards, we selected certain adjacent residential buildings, high-voltage lines along a specific street and selected different distances around its vertical projection point as monitoring points. The levels of electromagnetic radiations were measured respectively. In this investigation within the frequency of 5-1,000 Hz both the electric field strength and magnetic field strength of each monitoring sites were lower than the public exposure standards as determined by the International Commission on Non-Ionizing Radiation Protection. However, the electrical field strength on the roof adjacent to the high-voltage lines was significantly higher than that as measured on the other floors in the same buildings (p electromagnetic radiation measurements of different monitoring points, under the same high-voltage lines, showed the location which is nearer the high-voltage line maintain a consistently higher level of radiation than the more distant locations (p Electromagnetic radiation generated by high-voltage lines decreases proportionally to the distance from the lines. The buildings can to some extent shield (or absorb) the electric fields generated by high-voltage lines nearby. The electromagnetic radiation intensity near high-voltage lines may be mitigated or intensified by the manner in which the high-voltage lines are set up, and it merits attention for the potential impact on human health.

  20. Development of Voltage Regulation Plan by Composing Subsystem with the SFES for DC On-line Electric Vehicle

    Science.gov (United States)

    Jung, S.; Lee, J. H.; Yoon, M.; Lee, H.; Jang, G.

    The study of the application process of the relatively small size 'Superconducting Flywheel Energy Storage (SFES)' system is conducted to regulate voltage fluctuation of the DC On-Line Electric Vehicle (OLEV) system, which is designed by using DC power system network. It is recommended to construct the power conversion system nearby the substation because the charging system is under the low voltage. But as the system is usually built around urban area and it makes hard to construct the subsystems at every station, voltage drop can occur in power supply inverter that is some distance from the substation. As the alternative of this issue, DC distribution system is recently introduced and has possibility to solve the above issue. In this paper, SFES is introduced to solve the voltage drop under the low voltage distribution system by using the concept of the proposed DC OLEV which results in building the longer distance power supply system. The simulation to design the SFES by using DC power flow analysis is carried out and it is verified in this paper.

  1. Project resumes: biological effects from electric fields associated with high-voltage transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-01-01

    Abstracts of research projects are presented in the following areas: measurements and special facilities; cellular and subcellular studies; physiology; behavior; environmental effects; modeling, scaling and dosimetry; and high voltage direct current. (ACR)

  2. 架空输电线路微风振动防治措施介绍及瞻望%Measures of Introduction and Look Forward to Prevent Breeze Vibration of Overhead Power Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    李阔; 成印健; 成志

    2013-01-01

    随着输电线路大量兴建,输电线路微风振动问题也越来越引起线路工作人员的重视。为了防止线路因微风振动引起的破坏,在线路设计时要加强措施来防止振动破坏。采用自阻尼导线和防振线夹来防振是一种通过改变线路自身组成部分特性来防振的措施,采用护线条、阻尼线、防振锤、阻尼弹簧间隔棒这些消振装置来防振是另外一种有效的防振措施,两种方法可根据具体情况来选择采用。同时,在超高压乃至特高压迅速发展的今天,利用阻尼线与防振锤混合消振装置以及阻尼弹簧间隔棒来防止微风振动已经越来越受到电力工作者的青睐,成为了一种趋势。%Along with the power transmission lines of construction ,the problem to prevent breeze vibration has caused line workers' atten-tion more and more. To prevent lines for vibration caused by the breeze destruction,in the line design people must strengthen the measures to pre-vent the vibration damage. Adopting the damping wires and vibration- proof line clip to prevent vibration is an effective way by which changing the line itself component characteristics. Adopting Armor Rod, Damping Line, Vibration- proof Hammer,damping spring spacer these vibrating de-vices to prevent vibration is another kind of effective vibration control measures . The two methods can be adopted according to the specific condi-tions. At the same time when the extra high voltage system and even ultra high voltage system is on the development, Using damping line and vi-bration- proof hammer mixed vibrating device class and damping spring spacer to prevent breeze vibration has got the favour of power workers more and more.

  3. The account of sagging of wires at definition of specific potential factors of air High-Voltage Power Transmission Lines

    OpenAIRE

    2005-01-01

    The opportunity approached is shown, but more exact as it is usually accepted, the account of sagging of wires at definition of specific potential factors air High-Voltage Power Transmission Lines. The technique of reception of analytical expressions is resulted. For an opportunity of comparison traditional expressions for specific potential factors are resulted also. Communication of the offered and traditional analytical expressions is shown. Offered analytical expressions are not difficult...

  4. 29 CFR 1926.955 - Overhead lines.

    Science.gov (United States)

    2010-07-01

    ... excavation for pad- or pile-type footings in excess of 5 feet deep shall be either sloped to the angle of... pad- or pile-type footing excavations in excess of 4 feet. (2) When working in unstable material... printed on a plate of durable nonconductive material, and mounted in the buckets or its vicinity so as...

  5. High-voltage isolation transformer for sub-nanosecond rise time pulses constructed with annular parallel-strip transmission lines.

    Science.gov (United States)

    Homma, Akira

    2011-07-01

    A novel annular parallel-strip transmission line was devised to construct high-voltage high-speed pulse isolation transformers. The transmission lines can easily realize stable high-voltage operation and good impedance matching between primary and secondary circuits. The time constant for the step response of the transformer was calculated by introducing a simple low-frequency equivalent circuit model. Results show that the relation between the time constant and low-cut-off frequency of the transformer conforms to the theory of the general first-order linear time-invariant system. Results also show that the test transformer composed of the new transmission lines can transmit about 600 ps rise time pulses across the dc potential difference of more than 150 kV with insertion loss of -2.5 dB. The measured effective time constant of 12 ns agreed exactly with the theoretically predicted value. For practical applications involving the delivery of synchronized trigger signals to a dc high-voltage electron gun station, the transformer described in this paper exhibited advantages over methods using fiber optic cables for the signal transfer system. This transformer has no jitter or breakdown problems that invariably occur in active circuit components.

  6. 架空输电线路除冰机器人的样机研制及动力学仿真%Development and Dynamics Simulation of De-icing Robot for Overhead Power Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    张屹; 邵威; 朱大林; 邹圣权; 艾福洲; 朱险峰

    2011-01-01

    基于高压输电线路巡线机器人的研究,结合高压输电线路上覆冰的去除方法,设计了一种新型的高压输电线路除冰机器人.采用ADAMS软件对该机器人选行了运动学、动力学分析及仿真.结果表明,该机器人能在输电线上稳定地行走,并能较好地解决自主越障的问题,可完成输电线上的除冰任务.%Based on the research of power transmission lines inspection robot, a new robot for high voltage transmission lines deicing is designed by combination of transmission lines deicing method. Then, software ADAMS is applied to analyze and simulate the kinematies and dynamies of the robot. The results show that the robot can walk on transmission linen steadily and solve the problem of spanning barriers itself, which can complete deicing task of power transmission lines.

  7. Measurement of SIFT operating system overhead

    Science.gov (United States)

    Palumbo, D. L.; Butler, R. W.

    1985-01-01

    The overhead of the software implemented fault tolerance (SIFT) operating system was measured. Several versions of the operating system evolved. Each version represents different strategies employed to improve the measured performance. Three of these versions are analyzed. The internal data structures of the operating systems are discussed. The overhead of the SIFT operating system was found to be of two types: vote overhead and executive task overhead. Both types of overhead were found to be significant in all versions of the system. Improvements substantially reduced this overhead; even with these improvements, the operating system consumed well over 50% of the available processing time.

  8. Creating Great Overheads with Computers.

    Science.gov (United States)

    Gribas, Cyndy; And Others

    1996-01-01

    Steps in preparing effective overhead projector transparencies for college instruction are outlined, using the PowerPoint program for Windows. They include thinking analogically in translating from concept to visual form; using the features of the presentation program to create a polished product; and assuring readability (visibility, typeface…

  9. High-voltage transmission tower-line system subjected to disaster loads

    Institute of Scientific and Technical Information of China (English)

    LI Hongnan; BAI Haifeng

    2006-01-01

    The high-voltage power transmission system is an important lifeline structure. It is significant for wide researches on the features and ability of the system subjected to earthquake and environmental loads. The promising prosperity of the system has been demonstrated around the world. The corresponding advances of the system with respect to the mechanism of loading action, analytical methods, experimental research measurements, structural vibration control, fatigue damage, lifetime prediction, and design methods are comprehensively discussed herein. Finally, further research work on dynamic response characteristics of high-voltage transmission towerline system in the near future is predicted.

  10. Energized overhead ground wires - OHGWs the pioneer Brazilian application

    Energy Technology Data Exchange (ETDEWEB)

    D`Ajuz, Ary; Martinez, Manuel L.B.; Araujo, Ana Maria R.; Takai, Mario Noboru; Sganzerla, Flavio [ELETRONORTE, Brasilia, DF (Brazil); O. Junior, Helio P.; Fonseca, Claudio S. [Marte Engenharia (Brazil); Guimaraes, R.P.; Mendes, Eloisa R.

    1994-12-31

    This paper introduces an economical solution for close HV lines small villages and farms load supply. The needed modifications to adapt a planned transmission system to supply loads located along the lines routes are presented. The paper describes the two overhead ground wires scheme planned for implementation in the 230 kV transmission line under construction by ELETRONORTE in Mato Grosso and Rondonia supplying loads each one totaling roughly 8 MW. (author) 4 refs., 4 figs., 2 tabs.

  11. Prerequisites of the automated system of monitoring and early diagnosis of the state of high-voltage lines

    Directory of Open Access Journals (Sweden)

    Михайло Дмитрович Дяченко

    2015-03-01

    Full Text Available Violation of the contact connection leads either to breakage of the conductor, or fire equipment. Currently, for technical inspection of high voltage contact connections used method of thermal control or periodic visual inspection. Such control of long power lines becomes expensive. Therefore, to improve the reliability of connections required automatic condition monitoring of high-voltage contact connections. The system consists of a set of intelligent modules, located directly to contact connection and continuously measure its temperature and contact resistance. Microprocessor control module has a continuous connection with the same modules on other low-power contact connections via packet radio transceiver. The basis of the organization of an information network on the concept of self-organizing sensor networks. In it, each intelligent module performs the function of a router. It solves the problem of finding an optimal route data to central control. He can change the decision if conditions change operation transceiver equipment. This solution allows using a low-power transmitter to provide coverage in the long power lines more than hundreds km. And provide excellent data transmission quality. The proposed system allows continuous monitoring of each high-voltage power system contact connection, predict rejection of degradation of each of them and thus improve the reliability of power supply in general

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

    NARCIS (Netherlands)

    Baalbergen, J.F.

    2013-01-01

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

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

    NARCIS (Netherlands)

    Baalbergen, J.F.

    2013-01-01

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

  14. Automatic Distance Monitoring System of Contact Connections in High Voltage Equipment of Electric Power Lines

    Directory of Open Access Journals (Sweden)

    M. Diachenko

    2013-01-01

    Full Text Available The developed automatic distance monitoring system of contact connections in high voltage equipment is based on technology of sensor circuits. The paper shows application of control methodology for contact connections in accordance with time rate of conductor temperature changes and contact connection and also direct measurement of transient resistance.

  15. Study on Edge Extraction Methods for Image-based Icing On-line Monitoring on Overhead Transmission Lines%输电线路覆冰图像边缘提取方法研究

    Institute of Scientific and Technical Information of China (English)

    王小朋; 胡建林; 吴彬

    2008-01-01

    A new method of measuring the icing thickness of transmission lines on-line is proposed in this paper. In this method, the pictures of transmission lines which are photoed by the camera on the iron tower are processed immediately to extract the edges of the transmission line conductor and transmission line insulators. The icing thickness can be gained by comparing the edges of the iced transmission line and the uniced one. Two icing image edge extraction methods are described in detail, that is, a method based on the combination of the wavelet transform and the floating threshold method and a method based on the combination of the optimal threshold method and the mathematical morphology transform. The icing images from the artificial climatic chamber and transmission lines are used to test the methods above. The results show that the method based on the wavelet transform and the floating threshold method does well in the extraction of relatively smooth edges, such as glaze icing on conductor and icing on the insulator;meanwhile, the method based on the optimal threshold method and the mathematical morphology transform does well in the edge extraction of icing on the conductor, especially the opaque rime icing on the conductor with complicated edges.

  16. Influence of tube voltage and current on in-line phase contrast imaging using a microfocus x-ray source

    Institute of Scientific and Technical Information of China (English)

    Li Zheng; Yu Ai-Min; Li Cheng-Quan

    2007-01-01

    In-line x-ray phase contrast imaging has attracted much attention due to two major advantages:its effectiveness in imaging weakly absorbing materials,and the simplicity of its facilities.In this paper a comprehensive theory based on Wigner distribution developed by Wu and Liu [Med.Phys.31 2378-2384(2004)] is reviewed.The influence of x-ray source and detector on the image is discussed.Experiments using a microfocus x-ray source and a CCD detector are conducted,which show the role of two key factors on imaging:the tube voltage and tube current.High tube current and moderate tube voltage are suggested for imaging.

  17. Research on cost control and management in high voltage transmission line construction

    Science.gov (United States)

    Xu, Xiaobin

    2017-05-01

    Enterprises. The cost control is of vital importance to the construction enterprises. It is the key to the profitability of the transmission line project, which is related to the survival and development of the electric power construction enterprises. Due to the long construction line, complex and changeable construction terrain as well as large construction costs of transmission line, it is difficult for us to take accurate and effective cost control on the project implementation of entire transmission line. Therefore, the cost control of transmission line project is a complicated and arduous task. It is of great theoretical and practical significance to study the cost control scheme of transmission line project by a more scientific and efficient way. Based on the characteristics of the construction project of the transmission line project, this paper analyzes the construction cost structure of the transmission line project and the current cost control problem of the transmission line project, and demonstrates the necessity and feasibility of studying the cost control scheme of the transmission line project more accurately. In this way, the dynamic cycle cost control process including plan, implementation, feedback, correction, modification and re-implement is achieved to realize the accurate and effective cost control of entire electric power transmission line project.

  18. A comparison of 15 Hz sine on-line and off-line magnetic stimulation affecting the voltage-gated sodium channel currents of prefrontal cortex pyramidal neurons

    Science.gov (United States)

    Zheng, Yu; Dong, Lei; Gao, Yang; Dou, Jun-Rong; Li, Ze-yan

    2016-10-01

    Combined with the use of patch-clamp techniques, repetitive transcranial magnetic stimulation (rTMS) has proven to be a noninvasive neuromodulation tool that can inhibit or facilitate excitability of neurons after extensive research. The studies generally focused on the method: the neurons are first stimulated in an external standard magnetic exposure device, and then moved to the patch-clamp to record electrophysiological characteristics (off-line magnetic exposure). Despite its universality, real-time observation of the effects of magnetic stimulation on the neurons is more effective (on-line magnetic stimulation). In this study, we selected a standard exposure device for magnetic fields acting on mouse prefrontal cortex pyramidal neurons, and described a new method that a patch-clamp setup was modified to allow on-line magnetic stimulation. By comparing the off-line exposure and on-line stimulation of the same magnetic field intensity and frequency affecting the voltage-gated sodium channel currents, we succeeded in proving the feasibility of the new on-line stimulation device. We also demonstrated that the sodium channel currents of prefrontal cortex pyramidal neurons increased significantly under the 15 Hz sine 1 mT, and 2 mT off-line magnetic field exposure and under the 1 mT and 2 mT on-line magnetic stimulation, and the rate of acceleration was most significant on 2 mT on-line magnetic stimulation. This study described the development of a new on-line magnetic stimulator and successfully demonstrated its practicability for scientific stimulation of neurons.

  19. On-line condition monitoring systems for high voltage circuit breakers : a collaborative research project 1997-2001

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    A three year field project was initiated to review and evaluate the state of the art in on-line conditioning monitoring technology for a high voltage (240 kV SF6) circuit breaker located at Dorsey Converter Station. The ELF breaker is a three independent pole design which allows for three separate monitoring systems. This project involved the installation of a different type of monitoring system on each phase and incorporated many types of transducers. Each monitoring system measured the same basic parameters including contact travel, 'a' and 'b' auxiliary contacts, phase currents, coil currents, heater and pump current, plus SF6/CF4 pressure and temperature. Over the entire monitoring period the breaker was operated over 700 times at rated voltage and an additional 300 times during maintenance. Temperature conditions ranged from -35 to +30 degrees C. The use of on-line monitoring provided many valuable results and enhanced the knowledge base for the apparatus under the test. It was determined that on-line monitoring of HV circuit breakers has potential, but installation has to be considered carefully. Monitoring systems can offer improvement in the understanding of how circuit breakers work and provide input into RCM programs. However, monitoring systems themselves are subject to failure and require maintenance and attention. 2 refs., 2 tabs., 7 figs.

  20. The account of sagging of wires at definition of specific potential factors of air High-Voltage Power Transmission Lines

    Directory of Open Access Journals (Sweden)

    Suslov V.M.

    2005-12-01

    Full Text Available The opportunity approached is shown, but more exact as it is usually accepted, the account of sagging of wires at definition of specific potential factors air High-Voltage Power Transmission Lines. The technique of reception of analytical expressions is resulted. For an opportunity of comparison traditional expressions for specific potential factors are resulted also. Communication of the offered and traditional analytical expressions is shown. Offered analytical expressions are not difficult for programming on a personal computer of any class and besides they allow to make an estimation of an error of traditional expressions by means of parallel definition of specific potential factors by both ways.

  1. Switching Restrikes in HVAC Cable Lines and Hybrid HVAC Cable/OHL Lines

    DEFF Research Database (Denmark)

    da Silva, Filipe Miguel Faria; Bak, Claus Leth; Balle Holst, Per

    2011-01-01

    The disconnection of HV underground cables may, if unsuccessful, originate a restrike in the circuit breaker, leading to high overvoltages, and potentially damaging the cable and near equipment. Due to the cable high capacitance and low resistance the voltage damping is slow, resulting, half...... a cycle after the disconnection, in a voltage of approximately 2 pu at the circuit breaker terminals. In case of restrike in that instant, it is theoretical possible to attain an overvoltage of 3 pu. The overvoltage can be even larger in hybrid cable-Overhead Lines (OHL), due to voltage magnifications...

  2. 76 FR 26183 - Safety Zone; Repair of High Voltage Transmission Lines to Logan International Airport, Saugus...

    Science.gov (United States)

    2011-05-06

    ... to Logan International Airport, Saugus River, Saugus, MA AGENCY: Coast Guard, DHS. ACTION: Temporary... transmission lines to Logan Airport. This safety zone is required to provide for the safety of life on... Lines to Logan International Airport, Saugus River, Saugus, Massachusetts, in the Federal Register...

  3. 输电线路除冰机器人关键技术综述%Review on Key Technology of De-icing Robot Running on Overhead Transmission Line

    Institute of Scientific and Technical Information of China (English)

    王耀南; 魏书宁; 印峰; 杨易旻; 谭磊; 曹文明

    2011-01-01

    Ice-coated transmission lines seriously harm the safety and stability of the power grid. Compared with the traditional methods of de-icing, de-icing robots have advantages in terms of energy consumption, cost and safety, et al. As an emerging research area, international research on the de-icing robot is still in its infancy, and no mature technology can be used for reference. Thus it is necessary to review current achievements systematically and intensively. State-of-the-art in research and application of de-icing robot running on overhead transmission line are surveyed. Key technologies of de-icing robot are discussed in detail, including high reliability of motion mechanism design on complex flexible structure of transmission lines; autonomous behavior control and navigation in complex unstructured environment; efficient de-icing mechanism without damage; long-continuous power supply in a wide range of field work; remote communication, monitoring, teleoperation under the conditions of long distance and strong electromagnetic interference; special protection mechanisms under poor working conditions. Development trend and research direction for deicing robot are suggested in the end.%输电线路覆冰严重危害到电网的安全稳定运行,与传统除冰方法相比,采用机器人除冰在能耗、成本及安全性等方面具有优势.作为一个新兴的研究领域,国内外对除冰机器人的研究尚处在起步阶段,并没有成熟的技术可借鉴,因此有必要对现有研究成果进行系统分析和深入总结.回顾国内外高压输电线路除冰机器人的研究和应用现状,详细探讨了除冰机器人复杂柔性结构输电线缆上的高可靠性运动机构设计;复杂非结构化环境下的机器人自主行为控制与导航;无损伤高效除冰机构;野外大范围长时间工作的持续动力供给;远距离强电磁干扰条件下的机器人远程通信、监测和遥操作;恶劣工作环境中的本体

  4. Effects of Nonlinearities on Induced Voltages across Lumped Devices

    Directory of Open Access Journals (Sweden)

    Ziya Mazloom

    2011-01-01

    Full Text Available There have been many studies on induced currents and voltages along overhead conductors due to lightning flashes. In most of these studies lumped loads and components are connected only as line terminations [1]-[4]. In studies where series and shunt connected components are connected along the lines the effects of nonlinear components and effects are disregarded [5]-[8]. This is not always correct as nonlinear effects will introduce high frequencies in the system and affect the current and voltage wave distribution. In this paper the effects of series and shunt components and nonlinear phenomenon on a system representative of the Swedish electrified railway system will be investigated. It is seen how introduction of different linear and nonlinear components affect the propagating voltage wave forms.

  5. Test Results from a Simulated High Voltage Lunar Power Transmission Line

    Science.gov (United States)

    Birchenough, Arthur; Hervol, David

    2008-01-01

    The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, OH was modified to simulate high voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high frequency AC power to a lunar facility located at a distance.

  6. Test Results From a Simulated High-Voltage Lunar Power Transmission Line

    Science.gov (United States)

    Birchenough, Arthur; Hervol, David

    2008-01-01

    The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, Ohio was modified to simulate high-voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high-frequency ac power to a lunar facility located at a distance.

  7. Optical sensing in high voltage transmission lines using power over fiber and free space optics

    Science.gov (United States)

    Rosolem, João Batista; Bassan, Fabio Renato; Penze, Rivael Strobel; Leonardi, Ariovaldo Antonio; Fracarolli, João Paulo Vicentini; Floridia, Claudio

    2015-12-01

    In this work we propose the use of power over fiber (PoF) and free space optics (FSO) techniques to powering and receive signals from an electrical current sensor placed at high voltage potential using a pair of optical collimators. The technique evaluation was performed in a laboratorial prototype using 62.5/125 μm multimode fiber to study the sensitivity of the optical alignment and the influence of the collimation process in the sensing system wavelengths: data communication (1310 nm) and powering (830 nm). The collimators were installed in a rigid electric insulator in order to maintain the stability of transmission.

  8. Distributed voltage control and load sharing for inverter-interfaced microdrid with resistive lines

    DEFF Research Database (Denmark)

    Golsorkhi, Mohammad S.; Lu, D. D C; Shafiee, Q.

    2016-01-01

    method is based upon the practical assumption of resistive network impedance. In this context, a V-I droop mechanism is adopted in the primary control level, where GPS timing is used to synchronize the control agents. A new distributed secondary control method based on consensus protocol is introduced......This paper proposes a new distributed control method for coordination of distributed energy resources (DERs) in low-voltage resistive microgrids. The proposed framework consists of two level structure; primary and secondary control. Unlike the existing distributed control methods, the proposed...

  9. Characteristics of Rainfall in Wind Field of a Downburst and Its Effects on Motion of High-Voltage Transmission Line

    Directory of Open Access Journals (Sweden)

    Chao Zhou

    2017-01-01

    Full Text Available Despite most weather-related failures of high-voltage transmission lines (HVTLs being attributed to the downbursts accompanied by heavy rainfall, research works mainly focused on the behaviors of the high-voltage transmission tower-line structures under dry downburst winds. This paper thus presents a preliminary study to discuss the characteristics of rainfall in the downbursts and their effects on responses of HVTLs. Based on Vicroy model, the velocities of raindrops and their loads and pressure ratios of downburst wind-driven rain and only downburst wind on the surface of HVTLs per unit length are obtained. A downburst wind-rain induced vibration model is established to calculate the effects of the rainfall intensity and wind velocities on the motions of HVTLs. To verify the feasibility and accuracy of the model, the model is applied to evaluate responses of HVTLs with measured aerodynamic coefficients. The responses of HVTLs from the evaluated (the model and the field observation results are compared. The results indicated that the model is feasible and can capture main features of the rainfall acting on HVTLs in the downbursts. Furthermore, the effects of rainfall cannot be neglected, and more attention should be paid to the wet downbursts and their effects on aerodynamic property of HVTLs.

  10. Growth and yield of winter wheat (Triticum aestivum L.) and corn (Zea mays L.) near a high voltage transmission line.

    Science.gov (United States)

    Soja, G; Kunsch, B; Gerzabek, M; Reichenauer, T; Soja, A-M; Rippar, G; Bolhàr-Nordenkampf, H R

    2003-02-01

    The objective of this study was to determine the effects of an electromagnetic field from a high voltage transmission line on the yield of agricultural crops cultivated underneath and near the transmission line. For 5 years, experiments with winter wheat and corn were carried out near the 380 kV transmission line Dürnrohr (Austria)-Slavetice (Czech Republic). Different field strengths were tested by planting the crops at different distances from the transmission line. The plants were grown in experimental plots (1.77 m2), aligned to equal electric field strengths, and were cultivated according to standard agricultural practice. The soil for all plots was homogenized layer-specifically to a depth of 0.5 m to guarantee uniform soil conditions in the plant root environment. The soil was sampled annually for determinations of carbon content and the behavior of microbial biomass. During development of the vegetation, samples were collected at regular intervals for growth rate analyses. At physiological maturity, the plots (n = 8) were harvested for grain and straw yield determinations. The average electric and magnetic field strengths at four distances from the transmission line (nominal distances: 40, 14, 8, and 2 m) were between 0.2 and 4.0 kV/m and between 0.4 and 4.5 micro T, respectively. No effect of the field exposures on soil microbial biomass could be detected. The wheat grain yields were 7% higher (average of 5 years) in the plots with the lowest field exposure than in the plots nearer to the transmission line (P plants were more pronounced in years with drought episodes during grain filling than in humid years. No significant yield differences were found for corn yields. The extent of the yield variations attributed to the distance from the transmission line was small compared to the observed annual variations in climatic or soil specific site characteristics. Copyright 2003 Wiley-Liss, Inc.

  11. Dynamic simulation and experimental study of inspection robot for high-voltage transmission-line

    Institute of Scientific and Technical Information of China (English)

    XIAO Xiao-hui; WU Gong-ping; DU E; SHI Tie-lin

    2005-01-01

    A mobile robot developed by Wuhan University for full-path hotline inspection on 220 kV transmission lines was presented. With 4 rotating joints and 2 translational ones, such robot is capable of traveling along non-obstacle straight-line segment and surmounting straight-line segment obstacles as well as transferring between two spans automatically. Lagrange's equations were utilized to derive dynamic equations of all the links, including items of inertia, coupling inertia, Coriolis acceleration, centripetal acceleration and gravity. And a dynamic response experiment on elemental motions of robot prototype's travelling along non-obstacle straight-line segment and surmounting obstacles was performed on 220 kV 1∶1 simulative overhanging transmission-line in laboratory. In addition, dynamic numerical simulation was conducted in the corresponding condition. Comparison and analysis on results of experiment and numerical simulation have validated theoretical model and simulation resolution. Therefore, the dynamic model formed hereunder can be used for the study of robot control.

  12. Distance to high-voltage power lines and risk of childhood leukaemia – an analysis of confounding by and interaction with other potential risk factors

    DEFF Research Database (Denmark)

    Pedersen, Camilla; Bräuner, Elvira V.; Rod, Naja H.

    2014-01-01

    We investigated whether there is an interaction between distance from residence at birth to nearest power line and domestic radon and traffic-related air pollution, respectively, in relation to childhood leukemia risk. Further, we investigated whether adjusting for potential confounders alters....... We used geographical information systems to determine the distance between residence at birth and the nearest 132-400 kV overhead power line. Concentrations of domestic radon and traffic-related air pollution (NOx at the front door) were estimated using validated models. We found a statistically...... and traffic-related air pollution (p = 0.73). We found almost no change in the estimated association between distance to power line and risk of childhood leukemia when adjusting for socioeconomic status of the municipality, urbanization, maternal age, birth order, domestic radon and traffic-related air...

  13. On-line monitoring of base current and forward emitter current gain of the voltage regulator's serial pnp transistor in a radiation environment

    Directory of Open Access Journals (Sweden)

    Vukić Vladimir Đ.

    2012-01-01

    Full Text Available A method of on-line monitoring of the low-dropout voltage regulator's operation in a radiation environment is developed in this paper. The method had to enable detection of the circuit's degradation during exploitation, without terminating its operation in an ionizing radiation field. Moreover, it had to enable automatic measurement and data collection, as well as the detection of any considerable degradation, well before the monitored voltage regulator's malfunction. The principal parameters of the voltage regulator's operation that were monitored were the serial pnp transistor's base current and the forward emitter current gain. These parameters were procured indirectly, from the data on the voltage regulator's load and quiescent currents. Since the internal consumption current in moderately and heavily loaded devices was used, the quiescent current of a negligibly loaded voltage regulator of the same type served as a reference. Results acquired by on-line monitoring demonstrated marked agreement with the results acquired from examinations of the voltage regulator's maximum output current and minimum dropout voltage in a radiation environment. The results were particularly consistent in tests with heavily loaded devices. Results obtained for moderately loaded voltage regulators and the risks accompanying the application of the presented method, were also analyzed.

  14. Assessment of surge arrester failure rate and application studies in Hellenic high voltage transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Christodoulou, C.A.; Fotis, G.P.; Gonos, I.F.; Stathopulos, I.A. [National Technical University of Athens, School of Electrical and Computer Engineering, High Voltage Laboratory, 9 Iroon Politechniou St., Zografou Campus, 157 80 Athens (Greece); Ekonomou, L. [A.S.PE.T.E. - School of Pedagogical and Technological Education, Department of Electrical Engineering Educators, N. Heraklion, 141 21 Athens (Greece)

    2010-02-15

    The use of transmission line surge arresters to improve the lightning performance of transmission lines is becoming more common. Especially in areas with high soil resistivity and ground flash density, surge arresters constitute the most effective protection mean. In this paper a methodology for assessing the surge arrester failure rate based on the electrogeometrical model is presented. Critical currents that exceed arresters rated energy stress were estimated by the use of a simulation tool. The methodology is applied on operating Hellenic transmission lines of 150 kV. Several case studies are analyzed by installing surge arresters on different intervals, in relation to the region's tower footing resistance and the ground flash density. The obtained results are compared with real records of outage rate showing the effectiveness of the surge arresters in the reduction of the recorded failure rate. The presented methodology can be proved valuable to the studies of electric power systems designers intending in a more effective lightning protection, reducing the operational costs and providing continuity of service. (author)

  15. Distributed Interference Alignment with Low Overhead

    CERN Document Server

    Ma, Yanjun; Chen, Rui

    2011-01-01

    Based on closed-form interference alignment (IA) solutions, a low overhead distributed interference alignment (LOIA) scheme is proposed in this paper for the $K$-user SISO interference channel, and extension to multiple antenna scenario is also considered. Compared with the iterative interference alignment (IIA) algorithm proposed by Gomadam et al., the overhead is greatly reduced. Simulation results show that the IIA algorithm is strictly suboptimal compared with our LOIA algorithm in the overhead-limited scenario.

  16. Design and implementation of channel estimation for low-voltage power line communication systems based on OFDM

    Institute of Scientific and Technical Information of China (English)

    Zhao Huidong; Hei Yong; Qiao Shushan; Ye Tianchun

    2012-01-01

    An optimized channel estimation algorithm based on a time-spread structure in OFDM low-voltage power line communication (PLC) systems is proposed to achieve a lower bit error rate (BER).This paper optimizes the best maximum multi-path delay of the linear minimum mean square error (LMMSE) algorithm in time-domain spread OFDM systems.Simulation results indicate that the BER of the improved method is lower than that of conventional LMMSE algorithm,especially when the signal-to-noise ratio (SNR) is lower than 0 dB.Both the LMMSE algorithm and the proposed algorithm are implemented and fabricated in CSMC 0.18 μm technology.This paper analyzes and compares the hardware complexity and performance of the two algorithms.Measurements indicate that the proposed channel estimator has better performance than the conventional estimator.

  17. Current and voltage measurements at the contact line of the tramway in Brussels; Strom- und Spannungsmessungen an der Oberleitung der Strassenbahn Bruessel

    Energy Technology Data Exchange (ETDEWEB)

    Deutzer, M. [Deutzer Technische Kohle GmbH, Zeuthen (Germany); Winkin, W. [Gerken S.A., Petit-Rechain (Belgium)

    2007-07-01

    The contact line of the tramway in Brussels, Belgium, was designed to be negotiated with gliding shoes. After conversion to the operation with pantographs equipped with collector strips voltage break downs were often observed. Measurements of currents and voltages at the pantographs revealed that the design of the pantograph pan heads and rapid variations of the contact wire heights caused the unfavourable power transmission. (orig.)

  18. Voltage sags due to the short-circuits on transmission lines; Afundamentos de tensao provocados por curto-circuitos em linhas de transmissao

    Energy Technology Data Exchange (ETDEWEB)

    Klock Junior, Odemar Solano [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil)

    2001-07-01

    This paper analyses the voltage sags influence on the buses, including the ones where consumers of the COPEL transmission electric system, determining the sags number and the approximate values for short-circuits on transmission lines. The voltage values, during the the short-circuit regime are obtained from the data for the short-circuit program. The short-circuits are simulated by the assembly of the electric system impedance matrix, from where the voltage values for short-circuits on any point of the electric system can be determined using simply calculations.

  19. METHODICAL APPROACHES TO THE CHOICE OF THE NEW GENERATION OF HIGH-VOLTAGE POWER TRANSMISSION LINE 220 kV OPTIONS

    Directory of Open Access Journals (Sweden)

    POSTOLATI V.M.

    2010-08-01

    Full Text Available The Transmission Power Lines of new generation are described in the article (single- compact, double-circuit compact, double-circuit Controlled Self-compensating High Voltage Transmission Power Lines (CSHVL. Basic principles of creation, design elements and comparative characteristics of the transmission lines of the new generation are described, the advantages of its are showed. Methodical approaches to the choosing of a new generation of transmission lines and facilities management FACTS are formulated. Methodical approaches to the choice of options for transmission lines 220 kV and facilities management are shown.

  20. 试论高压输电线路的维护技术%On the High-voltage Transmission Line Maintenance Technology

    Institute of Scientific and Technical Information of China (English)

    邹长江

    2014-01-01

    Transmission lines with people’s daily lives have close ties. Once the high-voltage transmission line failure, will cause inconvenience to people’s lives. Thus, high-voltage transmission lines should do maintenance work;vigorously develop related maintenance techniques to ensure safe operation of the transmission lines. By analyzing the main characteristics of high-voltage transmission line maintenance, propose effective measures to maintain the high-voltage transmission lines.%输电线路与人们的日常生活具有紧密的联系。一旦高压输电线路出现故障,必将给人们的生活带来不便。由此可见,应做好高压输电线路的维护工作,大力开发相关维护技术,保障输电线路的安全运行。通过分析高压输电线路维护的主要特点,提出了维护高压输电线路的有效措施。

  1. Functional Expression of Voltage-Gated Sodium Channels Navl.5 in Human Breast Caner Cell Line MDA-MB-231

    Institute of Scientific and Technical Information of China (English)

    Rui GAO; Jing WANG; Yi SHEN; Ming LEI; Zehua WANG

    2009-01-01

    Voltage-gated sodium channels (VGSCs) are known to be involved in the initiation and progression of many malignancies,and the different subtypes of VGSCs play important roles in the metastasis cascade of many tumors.This study investigated the functional expression of Nav 1.5 and its effect on invasion behavior of human breast cancer cell line MDA-MB-231.The mRNA and pro-tein expression of Navl.5 was detected by real time PCR,Western Blot and immunofluorescence.The effects of Navl.5 on cell proliferation,migration and invasion were respectively assessed by MTT and Transwell.The effects of Nav1.5 on the secretion of matrix metalloproteases (MMPs) by MDA-MB-231 were analyzed by RT-PCR.The over-expressed Navl.5 was present on the membrane of MDA-MB-231 cells.The invasion ability in vitro and the MMP-9 mRNA expression were respec-tively decreased to (47.82±0.53)% and (43.97±0.64)% (P<0.05) respectively in MDA-MB-231 cells treated with VGSCs specific inhibitor tetrodotoxin (TTX) by blocking Navl.5 activity.It was con-eluded that Nav1.5 functional expression potentiated the invasive behavior of human breast cancer cell line MDA-MB-231 by increasing the secretion of MMP-9.

  2. Line-to-line voltage based modulation scheme for single-phase reduced switch ac-dc-ac converters to achieve improved performance

    DEFF Research Database (Denmark)

    Qin, Zian; Loh, Poh Chiang; Blaabjerg, Frede

    2015-01-01

    . With the SVPWM or DPWM proposed in literatures, the generation of the references is phase voltage based. But the phase voltages actually cannot be controlled directly by the PWM converter, since they can be influenced by both of terminal voltages and the load network while the PWM converter can only control...

  3. The principle of elaboration of the relay protection against short circuits between the closely placed phases of high voltage electrical line

    Directory of Open Access Journals (Sweden)

    Kiorsak M.

    2015-12-01

    Full Text Available The article is devoted to the elaboration of the principle of relay protection against short circuits between the closely placed phases of higher voltage electrical line with self-compensation, based on the six phase’s symmetrical components. It is shown that the unsymmetrical short circuits between the closely placed phases are characterized by appearance of zero and tertiary sequences of symmetrical components. This fact can be used to choose them for relay protection. The electrical basic circuits and formulas for calculation of the passive parameters of zero and tertiary filters of currents (voltages are done. It is presented the structural-functional basic circuit scheme for relay protection against short circuits between the closely placed phases of higher voltage electrical line with self-compensation.

  4. Static air-gap eccentricity fault diagnosis using rotor slot harmonics in line neutral voltage of three-phase squirrel cage induction motor

    Science.gov (United States)

    Oumaamar, Mohamed El Kamel; Maouche, Yassine; Boucherma, Mohamed; Khezzar, Abdelmalek

    2017-02-01

    The mixed eccentricity fault detection in a squirrel cage induction motor has been thoroughly investigated. However, a few papers have been related to pure static eccentricity fault and the authors focused on the RSH harmonics presented in stator current. The main objective of this paper is to present an alternative method based on the analysis of line neutral voltage taking place between the supply and the stator neutrals in order to detect air-gap static eccentricity, and to highlight the classification of all RSH harmonics in line neutral voltage. The model of squirrel cage induction machine relies on the rotor geometry and winding layout. Such developed model is used to analyze the impact of the pure static air-gap eccentricity by predicting the related frequencies in the line neutral voltage spectrum. The results show that the line neutral voltage spectrum are more sensitive to the air-gap static eccentricity fault compared to stator current one. The theoretical analysis and simulated results are confirmed by experiments.

  5. Middle & Low-voltage Transmission Lines Melting Ice Pragmatic Technology Research%中低压输电线路融冰实用技术研究

    Institute of Scientific and Technical Information of China (English)

    李宏力

    2014-01-01

    本文通过对现有的中低压输电线路融冰现状调查分析和研究,在此基础上提出了拥有完全自主知识产权的多项中低压输电线路融冰实用关键技术。通过这些实用关键技术的推广应用,解决了中低压输电线路的融冰技术问题,提高了融冰的工作效率。%Middle & low-voltage transmission lines melting ice pragmatic technology research. By existing middle & low-voltage transmission lines present Situation of melting ice investigation analysis and research, Who owns full independent intellectual property rights many middle &low-voltage transmission lines present Situation of melting ice key technology on this basis proposed. Through the practical application of key technologies, Solved middle&low-voltage transmission lines present Situation of melting ice technical problems, Improved the work efficiency of melting ice.

  6. Application of HFCT and UHF Sensors in On-Line Partial Discharge Measurements for Insulation Diagnosis of High Voltage Equipment

    Directory of Open Access Journals (Sweden)

    Fernando Álvarez

    2015-03-01

    Full Text Available Partial discharge (PD measurements provide valuable information for assessing the condition of high voltage (HV insulation systems, contributing to their quality assurance. Different PD measuring techniques have been developed in the last years specially designed to perform on-line measurements. Non-conventional PD methods operating in high frequency bands are usually used when this type of tests are carried out. In PD measurements the signal acquisition, the subsequent signal processing and the capability to obtain an accurate diagnosis are conditioned by the selection of a suitable detection technique and by the implementation of effective signal processing tools. This paper proposes an optimized electromagnetic detection method based on the combined use of wideband PD sensors for measurements performed in the HF and UHF frequency ranges, together with the implementation of powerful processing tools. The effectiveness of the measuring techniques proposed is demonstrated through an example, where several PD sources are measured simultaneously in a HV installation consisting of a cable system connected by a plug-in terminal to a gas insulated substation (GIS compartment.

  7. Field trial of composite fiber-optic overhead ground wire

    Science.gov (United States)

    Kubota, S.; Kawahira, H.; Nakajima, T.; Matsubara, I.; Saito, Y.; Kitayama, Y.

    A composite fiber-optic ground wire (OPGW), which provides additional communication capabilities for system protection and control of overhead power transmission systems has been developed. After laboratory tests, the OPGW was strung along a live power transmission line in a mountainous region and has been confirmed to have sufficient performance to establish a high-speed digital transmission network able to withstand actual conditions. The field line, constructed substantially by existing techniques, has proved that the new OPGW, accessories such as clamps and joint boxes, installation technique, and on-tower splicing method can be effectively utilized to produce a protection and control system with extremely stable characteristics.

  8. The Power Behind the Controversy: Understanding Local Policy Elites' Perceptions on the Benefits and Risks Associated with High Voltage Power Line Installation in the State of Arkansas

    Science.gov (United States)

    Moyer, Rachael M.

    Following a proposal for the installation of high voltage power lines in northwest Arkansas, a controversial policy debate emerged. Proponents of the transmission line argue that such an installation is inevitable and necessary to efficiently and reliably support the identified electric load in the region. Opponents claim that the lines will degrade the natural environment and hamper the tourism-based local economy in affected regions, notably in Ozark Mountain areas. This study seeks to understand how local policy elites perceive the benefits and risks associated with proposed transmission lines, which is a critical step in comprehending the formation and changes of related government policies. First, based upon the dual process theory of judgment, this study systematically investigates the triadic relationships between (a) more profound personal value predispositions, (b) affects and feelings, and (c) perceived benefits and risks related to the proposed installation of high voltage power lines among local policy elites in the state of Arkansas. Next, this study focuses more specifically on the role of value predispositions, specific emotional dimensions of affect heuristics, and perceptions pertaining to high voltage power line risks and benefits. Using original data collected from a statewide Internet survey of 420 local leaders and key policymakers about their opinions on the related issues, other factors claimed by previous literature, including trust, knowledge level, and demographic characteristics are considered. Analytical results suggest that grid-group cultural predispositions, as deeply held core values within local policy elites' individual belief systems, both directly and indirectly -- through affective feelings -- shape perceived utility associated with the installation of high voltage power lines. Recognizing that risk perceptions factor into policy decisions, some practical considerations for better designing policy addressing controversial issues

  9. Conventional P-ω/Q-V Droop Control in Highly Resistive Line of Low-Voltage Converter-Based AC Microgrid

    DEFF Research Database (Denmark)

    Hou, Xiaochao; Sun, Yao; Yuan, Wenbin

    2016-01-01

    In low-voltage converter-based alternating current (AC) microgrids with resistive distribution lines, the P-V droop with Q-f boost (VPD/FQB) is the most common method for load sharing. However, it cannot achieve the active power sharing proportionally. To overcome this drawback, the conventional P......-ω/Q-V droop control is adopted in the low-voltage AC microgrid. As a result, the active power sharing among the distributed generators (DGs) is easily obtained without communication. More importantly, this study clears up the previous misunderstanding that conventional P-ω/Q-V droop control is only applicable...... to microgrids with highly inductive lines, and lays a foundation for the application of conventional droop control under different line impedances. Moreover, in order to guarantee the accurate reactive power sharing, a guide for designing Q-V droop gains is given, and virtual resistance is adopted to shape...

  10. SLAP lesions in the overhead athlete.

    Science.gov (United States)

    Rokito, Steven E; Myers, Kevin R; Ryu, Richard K N

    2014-06-01

    The diagnosis and management of SLAP lesions in the overhead athlete remains a challenge for the sports medicine specialist due to variable anatomy, changes with aging, concomitant pathology, lack of dependable physical findings on examination, and lack of sensitivity and specificity with imaging studies. This article presents a comprehensive review of the epidemiology, relevant anatomy, proposed pathogenesis, diagnostic approach, and outcomes of nonoperative and operative management of SLAP lesions in the overhead athlete.

  11. Performance enhancement of the single-phase series active filter by employing the load voltage waveform reconstruction and line current sampling delay reduction methods

    DEFF Research Database (Denmark)

    Senturk, O.S.; Hava, A.M.

    2011-01-01

    This paper proposes the waveform reconstruction method (WRM), which is utilized in the single-phase series active filter's (SAF's) control algorithm, in order to extract the load harmonic voltage component of voltage harmonic type single-phase diode rectifier loads. Employing WRM and the line...... current sampling delay reduction method, a single-phase SAF compensated system provides higher harmonic isolation performance and higher stability margins compared to the system using conventional synchronous-reference-frame-based methods. The analytical, simulation, and experimental studies of a 2.5 k......W single-phase SAF compensated system prove the theory....

  12. Transient Recovery Voltages at the Main 132kV Line Bay GIS Circuit Breaker in a Windfarm

    DEFF Research Database (Denmark)

    Arana Aristi, Iván; Okholm, J.; Holbøll, Joachim

    2011-01-01

    parameters in the network was evaluated during a fault in the onshore substation. The rate of rise of recovery voltage (RRRV) and the maximum crest voltage (Uc) of the TRV across the GIS CB were compared against the standard values based on the type test results from the GIS. The investigations were...

  13. Assessment of overhead line cascade using finite element model[Includes the CSCE forum on professional practice and career development : 1. international engineering mechanics and materials specialty conference : 1. international/3. coastal, estuarine and offshore engineering specialty conference : 2. international/8. construction specialty conference

    Energy Technology Data Exchange (ETDEWEB)

    Haldar, A.; Veitch, M.; Andrews, T. [Newfoundland and Labrador Hydro, St. John' s, NL (Canada). Engineering Services Division

    2009-07-01

    Newfoundland and Labrador Hydro operates transmission lines that have experienced a number of severe ice storm failures. Although overhead transmission lines are designed to withstand meteorological loads, a line could be subjected to dynamic overloading when a triggering event is caused by a component failure. A cascade failure can occur if the capacity of the remaining system can not support the force redistribution. This paper presented a systematic approach to estimate the length of a cascade failure zone of an existing steel power transmission line under broken conductor scenario. A finite element model of a typical line section was developed using automatic dynamic incremental nonlinear analysis (ADINA). A typical 230 kV line section was considered in this study, where both transient (peak dynamic) and steady state (quasi static residual) loads were evaluated. The numerical model assumed the following cases: (1) the first tower next to the break was intact and (2) the first tower failed and the force redistribution in the remaining line system was assessed. Next, a scenario with more than one tower failure was considered. Based on the location of the first surviving tower after a failure, the most probable extent of the failure zone was estimated and the mitigation to strengthen the tower to withstand the required containment load was proposed. All possible 5 load cases were considered in the dynamic analysis. Considering the dynamic capacity of an upgraded tower, the expected tower loss would be as little as two towers while under original static capacity, this could be ten towers. The methodology was found to be quite robust and was equally applicable with some ice loading on the conductor where the initial tension and the ice weight of the cable would be larger. 9 refs., 2 tabs., 13 figs.

  14. Performance analysis of the PLC (Power Line Communication) in medium voltage electrical networks; Analise de desempenho de sistemas PLC em redes eletricas de media tensao

    Energy Technology Data Exchange (ETDEWEB)

    Mota, A.A.; Paleta, R. [Pontificia Universidade Catolica de Campinas (PUC-Campinas), SP (Brazil)], E-mail: amota@puc-campinas.edu.br; Mota, L.T.M.; Ricardo, R.A. [Indelmatec Engenharia, Campinas, SP (Brazil)], E-mail: mota@indelmatec.com.br

    2009-07-01

    Nowadays, the information access in communication networks is widely explored due to the increase of Internet users. In this context, the PLC (Power Line Communication) technology is an alternative for data transmission. This technology is based on the usage of transmission/distribution power lines for data transmission. However there are some problems related to the usage of this technology: adequate data transmission rates and generation of acceptable levels of electromagnetic interference (EMI). This work had the objective of studying the performance of PLC systems in medium voltage electrical networks, through the assess of data transmission rates and the generated EMI. Tests were carried out in a test field that corresponded to a medium voltage electrical network and the obtained results show that, under some circumstances, the PLC system does not reach the existent technical recommendations. (author)

  15. LTPS-TFT Pixel Circuit Compensating for TFT Threshold Voltage Shift and IR-Drop on the Power Line for AMOLED Displays

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2012-01-01

    Full Text Available We propose a new pixel design for the active matrix organic light-emitting diode (AMOLED using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs. The proposed pixel is composed of four switching TFTs, one driving TFT (DTFT, and one capacitor. The simulation results are performed by AIM-SPICE software. The error rate of OLED output current with (threshold voltage variation (0.3 V and power line drop by 1 V are improved to about 1.67% and 15%, respectively. Thus, the proposed pixel circuit can successfully overcome drawbacks suffered from DTFT threshold voltage deviation and IR-drop on power line.

  16. 3D Object Visual Tracking for the 220 kV/330 kV High-Voltage Live-Line Insulator Cleaning Robot

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian; YANG Ru-qing

    2009-01-01

    The 3D object visual tracking problem is studied for the robot vision system of the 220 kV/330 kV high-voltage live-line insulator cleaning robot. The SUSAN Edge based Scale Invariant Feature (SESIF) algorithm based 3D objects visual tracking is achieved in three stages: the first frame stage, tracking stage, and recovering stage. An SESIF based objects recognition algorithm is proposed to fred initial location at both the first frame stage and recovering stage. An SESIF and Lie group based visual tracking algorithm is used to track 3D object. Experiments verify the algorithm's robustness. This algorithm will be used in the second generation of the 220 kV/330 kV high-voltage five-line insulator cleaning robot.

  17. Development of lightning-resistant overhead ground wire

    Energy Technology Data Exchange (ETDEWEB)

    Yokoya, Munehisa; Katsuragi, Yukio (Chubu Electric Power Co., Inc., Nagoya (Japan)); Goda, Yutaka (Central Research Inst. of the Electric Power Industry, Yokosuka (Japan)); Nagata, Yutaka; Asano, Yuji (Fujikura Ltd., Tokyo (Japan))

    1994-07-01

    Overhead ground wires (GW) are vulnerable to strand breakage due to lightning strikes. With the wider application in recent years of Composite Fiber Optic Ground Wire (OPGW), it becomes more important to protect GW from such damage. In this paper, the authors present the results of various investigations made in developing lightning-resistant GW/OPGW. Investigations included field experiments using rocket-triggered lightning, studies on materials and designs to improve lightning characteristics and various evaluation tests, such as DC arc tests, of several prototypes. As a result, the authors have developed excellent lightning-resistant GW/OPGW applicable for conventional transmission lines.

  18. [Childhood leukaemia in a residential area with a high-voltage power line: approach according to the Dutch Community Health Services' guideline 'Cancer Clusters'].

    Science.gov (United States)

    Hegger, Carola; Reedijk, Ardine M J

    2013-01-01

    The new Dutch Community Health Services' (GGD) guideline titled 'Cancer Clusters' describes a phased plan for investigating reported cancer clusters. In each phase, attention is paid to both health and environmental issues and their possible links to one another. Throughout the entire cluster investigation, good risk communication is essential. In accordance with the new guideline, the Rotterdam-Rijnmond Public Health Services investigated the incidence of childhood leukaemia in a residential area as well as the data available on the high-voltage power line located there. More children in this residential area had been diagnosed with leukaemia than expected. However, the children had not been subjected to prolonged exposure to strong magnetic fields emitted from the high-voltage power line. With this type of cluster investigation, it is not possible to establish a causal relationship between childhood leukaemia and high-voltage power lines. However, the research did provide stakeholders insight into the health-and-environment situation and thereby, the opportunity to assess the situation appropriately and to act accordingly, if desired.

  19. Study of the Type Selection in the Design of the OPGW Used in Ultra-High Voltage (UHV) Overhead Transmission Lines%特高压架空输电线路OPGW的设计选型研究

    Institute of Scientific and Technical Information of China (English)

    谢书鸿; 李海全

    2007-01-01

    通过简要总结国外为数不多的特高压架空输电线路光纤复合架空地线(OPGW)应用经验和我国超高压OPGW的运行经验,指出特高压OPGW必须具有良好的防雷特性、防振特性和耐电晕特性等技术特点,在此基础上分析及提出特高压OPGW的系列设计选型建议:如采用更大单丝直径的全铝包钢绞合OPGW;深入研究地线(包括OPGW)的配置方式;设计使用新型的紧压型耐雷的OPGW;对OPGW选型和系列进行研究、分析,为特高压电网提供结构合理和性能优良的新型OPGW.

  20. Overhead-Aware-Best-Fit (OABF) Resource Allocation Algorithm for Minimizing VM Launching Overhead

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hao [IIT; Garzoglio, Gabriele [Fermilab; Ren, Shangping [IIT, Chicago; Timm, Steven [Fermilab; Noh, Seo Young [KISTI, Daejeon

    2014-11-11

    FermiCloud is a private cloud developed in Fermi National Accelerator Laboratory to provide elastic and on-demand resources for different scientific research experiments. The design goal of the FermiCloud is to automatically allocate resources for different scientific applications so that the QoS required by these applications is met and the operational cost of the FermiCloud is minimized. Our earlier research shows that VM launching overhead has large variations. If such variations are not taken into consideration when making resource allocation decisions, it may lead to poor performance and resource waste. In this paper, we show how we may use an VM launching overhead reference model to minimize VM launching overhead. In particular, we first present a training algorithm that automatically tunes a given refer- ence model to accurately reflect FermiCloud environment. Based on the tuned reference model for virtual machine launching overhead, we develop an overhead-aware-best-fit resource allocation algorithm that decides where and when to allocate resources so that the average virtual machine launching overhead is minimized. The experimental results indicate that the developed overhead-aware-best-fit resource allocation algorithm can significantly improved the VM launching time when large number of VMs are simultaneously launched.

  1. Lightning-induced overvoltages in medium voltage distribution systems and customer experienced voltage spikes

    Energy Technology Data Exchange (ETDEWEB)

    Sabiha, N. A.

    2010-07-01

    In Finland, distribution transformers are frequently subjected to lightning strokes for which they are continuously protected by spark-gaps. So, the breakdown probability of medium voltage (MV) spark-gaps is modeled using the Gaussian distribution function under an impulse voltage test in accordance with the IEC 60060-1 standard. The model is presented in the form of the well-known Gaussian tail probability. Accordingly, a modified probabilistic model is proposed to study the effect of impulse voltage superimposed on the ac voltage on the breakdown probability of MV spark-gaps. The modified model is verified using experimental data, where the experimental setup is arranged to generate a range of impulse voltages superimposed on the ac voltages. The experimental verification shows evidence of the efficacy of the proposed probabilistic model. Furthermore, the proposed model is used to evaluate single-phase, two-phase and three-phase spark-gap breakdown probabilities in the case of lightning induced overvoltages. These breakdown probabilities are used along with the simplified Rusck expression to evaluate the performance of MV overhead lines above a perfectly conducting ground under lightning-induced overvoltages using a statistical approach. In order to study the overvoltages propagating through the transformer to its low voltage side, the high frequency model of the transformer is investigated. First, the investigation is carried out using model introduced by Piantini at no-load condition. This model is modified to take more than one resonance frequency into consideration. Therefore, the frequency response of the simulated transient voltage is improved. A verification of the modified model is carried out through the comparison between the experimental and simulation results, in which the time domain simulation is carried out using ATP/EMTP while MATLAB is used to identify the model parameters. As this model is found suitable only for unloaded transformer, an

  2. Simplification Study of FE Model for 1000kV AC Transmission Line Insulator String Voltage and Grading Ring Surface Electric Field Distribution Calculation

    Directory of Open Access Journals (Sweden)

    Guoli Wang

    2013-09-01

    Full Text Available The finite element model of the 1000kV Ultra High Voltage (UHV AC transmission line porcelain insulator string voltage distribution and grading ring surface electric field distribution calculation has the characteristics of large size, complicated structure and various mediums. To insure the accuracy, related influencing factors should be considered to simplify the model reasonably for improving computational efficiency. A whole model and a simplified 3D finite element model of UHV AC transmission line porcelain insulator string were built. The influencing factors including tower, phase conductors, hardware fittings, yoke plate and phase interaction were considered in the analysis. And finally, the rationality of the simplified model was validated. The results comparison show that building a simplified model of three-phase bundled conductors within a certain length, simplifying the tower reasonably, omitting the hardware fittings and yoke plate and containing only single-phase insulator string model is feasible. The simplified model could replace the whole model to analyze the voltage distribution along the porcelain insulator string and the electric field distribution on the grading ring surface, and it can reduce the calculation scale, improve optimization efficiency of insulators string and grading ring parameters.

  3. Measurement and Modeling of Personal Exposure to the Electric and Magnetic Fields in the Vicinity of High Voltage Power Lines

    Directory of Open Access Journals (Sweden)

    Wafa Tourab

    2016-06-01

    Conclusion: We project to set own national standards for exposure to electromagnetic fields, in order to achieve a regional database that will be at the disposal of partners concerned to ensure safety of people and mainly workers inside high voltage electrical substations.

  4. Aluminium overhead highway traffic sign structures

    NARCIS (Netherlands)

    Courage, W.M.G.; Soetens, F.; Noordzij, R.; Drabbels, J.

    1998-01-01

    This paper deals with the design and manufacturing of aluminium overhead sign structures. These gantries are built up by using two X-shaped column frames connected by a triangular space frame girder. Slenderness and a low solidity ratio were objectives in the architectonic design. Braces and main ch

  5. Environmental Assessment, Finding of No Significant Impact/Finding of No Practicable Alternative for Replacement of Overhead Electrical Line, Feeders K1 and K7, Vandenberg Air Force Base, California

    Science.gov (United States)

    2012-09-19

    Maritime chaparral is a dense, evergreen, rigid , fire-adapted form of shrubby vegetation unique to California’s coastal areas. Chaparral provides...traffic to shift to a roadway that was incompatible with those traffic increases (e.g., inadequate pavement structure or design capacity), or could... pavement or dirt turnouts and are included in the APE. Project Location Each of the feeder lines begins at Substation K on Bear Creek Road and

  6. Understanding Local Policy Elites' Perceptions on the Benefits and Risks Associated with High-Voltage Power Line Installations in the State of Arkansas.

    Science.gov (United States)

    Moyer, Rachael M; Song, Geoboo

    2016-10-01

    Recently, a controversial policy debate has arisen concerning the installation of high-voltage power lines in northwest Arkansas. While proponents argue that such an installation is inevitable to efficiently and reliably support the identified electric load in the region, opponents claim that the lines will degrade the natural environment and hamper the tourism-based local economy in affected regions, notably in Ozark Mountain areas. Of particular interest is to understand how local policy elites perceive the benefits and risks associated with such divisive proposals, which is critical for comprehending the formation and changes of related government policies. Based upon the dual process theory of judgment, this study systematically investigates the triadic relationships between (a) more profound personal value predispositions, (b) affects and feelings, and (c) perceived benefits and risks related to the proposed installation of high-voltage power lines among local policy elites in the state of Arkansas. In doing so, we analyze original data collected from a statewide Internet survey of 420 local leaders and key policymakers about their opinions on the related issues, while considering other factors claimed by previous literature to influence risk perceptions, including trust, knowledge level, and demographic characteristics. Analytical results suggest that grid-group cultural predispositions, as deeply held core values within local policy elites' individual belief systems, both directly and indirectly-through affective feelings-shape perceived utility associated with the installation of high-voltage power lines. We conclude this article by suggesting some practical considerations for better designing policy addressing controversial issues of this nature. © 2016 Society for Risk Analysis.

  7. Determination of High-Frequency Current Distribution Using EMTP-Based Transmission Line Models with Resulting Radiated Electromagnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Mork, B; Nelson, R; Kirkendall, B; Stenvig, N

    2009-11-30

    Application of BPL technologies to existing overhead high-voltage power lines would benefit greatly from improved simulation tools capable of predicting performance - such as the electromagnetic fields radiated from such lines. Existing EMTP-based frequency-dependent line models are attractive since their parameters are derived from physical design dimensions which are easily obtained. However, to calculate the radiated electromagnetic fields, detailed current distributions need to be determined. This paper presents a method of using EMTP line models to determine the current distribution on the lines, as well as a technique for using these current distributions to determine the radiated electromagnetic fields.

  8. On-line Over-voltage Detector Based on LabVIEW%基于LabVIEW的过电压在线检测仪

    Institute of Scientific and Technical Information of China (English)

    程刚; 王肖剑

    2012-01-01

    过电压在线检测仪主要用于变电站过电压在线检测,能自动追踪、并以较高的采样速率和采样深度记录内外过电压的波形、幅值及相关信息,并可查询已保存的过电压历史数据,同时实现对波形的多种操作;过电压在线检测仪采用电容分压器和NI公司的图形化编程软件LabVIEW等组成;经过运行证明该装置运行正常、稳定、可靠,能在过电压发生时完整、准确地同时记录下六路瞬态过电压信号,为更好的绝缘配合、修订绝缘水平提供有力参考.%On-Line over-voltage detector is mainly used for detection over -voltage of substation, automatic tracking, with higher sampling rate and sampling depth of the wave, both inside and outside record over voltage amplitude and related information, and inquires the historical overvoltage data, to realize the varied waveform operation. On-line over-voltage detector composed by capacitive divider and NI's Lab VIEW graphical programming software etc. The device run normally, stable and reliable, it can accurate record six channel transient overvoltage signals at the same time, it provide powerful reference for better insulation coordination and revise insulation level.

  9. Control of grid integrated voltage source converters under unbalanced conditions: development of an on-line frequency-adaptive virtual flux-based approach

    Energy Technology Data Exchange (ETDEWEB)

    Suul, Jon Are

    2012-03-15

    Three-Phase Voltage Source Converters (VSCs) are finding widespread applications in grid integrated power conversion systems. The control systems of such VSCs are in an increasing number of these applications required to operate during voltage disturbances and unbalanced conditions. Control systems designed for grid side voltagesensor-less operation are at the same time becoming attractive due to the continuous drive for cost reduction and increased reliability of VSCs, but are not commonly applied for operation during unbalanced conditions. Methods for voltage-sensor-less grid synchronization and control of VSCs under unbalanced grid voltage conditions will therefore be the main focus of this Thesis. Estimation methods based on the concept of Virtual Flux, considering the integral of the converter voltage in analogy to the flux of an electric machine, are among the simplest and most well known techniques for achieving voltage-sensor-less grid synchronization. Most of the established techniques for Virtual Flux estimation are, however, either sensitive to grid frequency variations or they are not easily adaptable for operation under unbalanced grid voltage conditions. This Thesis addresses both these issues by proposing a simple approach for Virtual Flux estimation by utilizing a frequency-adaptive filter based on a Second Order Generalized Integrator (SOGI). The proposed approach can be used to achieve on-line frequency-adaptive varieties of conventional strategies for Virtual Flux estimation. The main advantage is, however, that the SOGI-based Virtual Flux estimation can be arranged in a structure that achieves inherent symmetrical component sequence separation under unbalanced conditions. The proposed method for Virtual Flux estimation can be used as a general basis for voltage-sensor-less grid synchronization and control during unbalanced conditions. In this Thesis, the estimated Virtual Flux signals are used to develop a flexible strategy for control of active

  10. 提高架空输电线路运行的安全可靠性与经济性%Improve Safety-Reliability and Economy of Overhead Transmission Lines in Operation

    Institute of Scientific and Technical Information of China (English)

    王向坤; 董达鹏

    2011-01-01

    The current transmission lines' safety-reliability and economics in operation face many challenges. This paper in-depth analysis the safe- ty-reliability issues and economic issues in operation of transmission lines. And from increasing the intensity of line inspection, setting up online monitoring systems, developing condition-based maintenance, improving design capabilities these four angels gives the corresponding measures and countermeasures.%当前输电线路在运行的安全可靠性与经济性方面面临诸多挑战。本文深入分析了线路运行中的安全可靠性问题与经济性问题。并从加大线路巡视力度、建立在线监测系统、开展状态检修、提高设计能力等四个角度给出了相应的措施与对策。

  11. 高压电缆线路不间断取能电源的研究%Research on Uninterruption Power Sources of High-voltage Cable Line

    Institute of Scientific and Technical Information of China (English)

    殷迪清; 韩跃峻; 胡顺

    2011-01-01

    To solve the power supply problem of secondary equipment application m distribution network field, this paper designs uninterruption power sources of high voltage line. The main part of power supply obtains the induced current of high voltage cable line through open current coil. Solar power and lithium battery with charge and discharge are taken as auxiliary power supply, which can solve the problem of inadequate power supply under the conditions of line small load current The automatic switching mode is used to ensure uninterruption power supply output and seamless switching.%为解决电网二次设备在现场应用中的供电电源问题,提出了一种高压电缆线路的不间断取能电源设计,电源的主供电部分通过开口取能线圈从一次电缆线路的电流上取能,并辅助有太阳能电池供电和锂电池充放电,以解决电网中负荷电流较小情况下的供电不足问题,通过自动切换方式确保电源的不间断输出和元缝隙切换.

  12. Conventional P-ω/Q-V Droop Control in Highly Resistive Line of Low-Voltage Converter-Based AC Microgrid

    Directory of Open Access Journals (Sweden)

    Xiaochao Hou

    2016-11-01

    Full Text Available In low-voltage converter-based alternating current (AC microgrids with resistive distribution lines, the P-V droop with Q-f boost (VPD/FQB is the most common method for load sharing. However, it cannot achieve the active power sharing proportionally. To overcome this drawback, the conventional P-ω/Q-V droop control is adopted in the low-voltage AC microgrid. As a result, the active power sharing among the distributed generators (DGs is easily obtained without communication. More importantly, this study clears up the previous misunderstanding that conventional P-ω/Q-V droop control is only applicable to microgrids with highly inductive lines, and lays a foundation for the application of conventional droop control under different line impedances. Moreover, in order to guarantee the accurate reactive power sharing, a guide for designing Q-V droop gains is given, and virtual resistance is adopted to shape the desired output impedance. Finally, the effects of power sharing and transient response are verified through simulations and experiments in converter-based AC Microgrid.

  13. 架空输电线路绝缘子检测机器人的设计与研究%The research and design of overhead transmission line insulator detecting robot

    Institute of Scientific and Technical Information of China (English)

    张林华; 池艳东

    2015-01-01

    Insulator in long-term operation under electrical load, cold, appear to reduce insulation resistance, cracking of insulator, and so on and so forth; For large power supply security hidden danger, to develop a insulator electric inspection robot become an effective solution. Robot can complete on insulator string before and after the move, the automatic detection of insulator insulation performance and appearance characteristics of surface defects of inferior insulator and effectively discriminant and early warning, improve the efficiency of maintenance, transmission line operations to reduce costs, improve the management level of the whole line insulator string.%绝缘子在运行过程中长期承受机电负载、冷热变化,会出现绝缘电阻降低、绝缘子开裂等情况;对供电安全带来较大隐患,设计一种绝缘子带电检测机器人成为一种有效的解决方案。机器人可完成在绝缘子串上的前后移动,自动检测绝缘子片的绝缘性能和外观特征,对劣质绝缘子及表面缺陷进行有效判别及预警,提高检修效率,降低输电线路运维成本,提高整个线路绝缘子串的整体管理水平。

  14. Design and measurements of a fast high-voltage pulse generator for the MedAustron Low Energy Transfer line fast deflector

    CERN Document Server

    Fowler, T; Mueller, F; Kramer, T; Stadlbauer, T

    2012-01-01

    MedAustron, a centre for ion-therapy and research, will comprise an accelerator facility based on a synchrotron for the delivery of protons and light ions for cancer treatment. The Low Energy Beam Transfer line (LEBT) to the synchrotron contains an electrostatic fast deflector (EFE) which, when energized, deviates the continuous beam arriving from the ion source onto a Faraday Cup: the specified voltage is ±3.5 kV. De-energizing the EFE for variable pulse durations from 500 ns up to d.c. allows beam passage for multi-turn injection into the synchrotron. To maintain beam quality in the synchrotron, the EFE pulse generator requires rise and fall times of less than 300 ns between 90 % of peak voltage and a ±1 V level. To achieve this, a pulsed power supply (PKF), with high voltage MOSFET switches connected in a push-pull configuration, will be mounted in close proximity to the deflector itself. A fast, large dynamic range monitoring circuit will verify switching to the ±1 V level and subsequent flat bottom pu...

  15. Discourses of energy infrastructure development: a Q-method study of electricity transmission line siting in the UK

    OpenAIRE

    Matthew Cotton; Patrick Devine-Wright

    2011-01-01

    The construction of new electricity-transmission infrastructure is construed in UK energy policy documents as necessary for achieving government targets to increase low-carbon electricity provision to combat climate change and ensure long-term energy security. Siting high-voltage overhead lines and substations is publicly controversial, however, due to their potential environmental, social, and economic impacts. Also controversial are issues of governance, procedural justice, and technologica...

  16. 低压配电线路中的电弧故障与防控%Arc Fault Prevention and Control for Low-voltage Distribution Branch Line

    Institute of Scientific and Technical Information of China (English)

    任长宁; 杨栋

    2012-01-01

    对低压配电线路中的电弧故障进行分析.并对国内外相关标准、保护电器发展情况、电弧故障定位技术进行介绍.阐述对低压配电线路电弧故障防控的重要性。据公安部消防局2005年至2010年统计.我国电气火灾发生率均接近或超过30%.高居各类火灾原因之首。而据2003年至2007年国内重特大电气火灾起火源统计[1].“电气线路引起火灾”比例高达58.44%,居首位(见图1)。%This paper analyzes the arc fault in low- voltage distribution line and introduces the domestic and foreign related standards, the development of protective device and addition, prevention it for the arc fault also explains the locating technology. importance of arc low-voltage distribution line In fault

  17. Research on High-voltage Transmission Line Operation and Maintenance Management%对高压输电线路运维管理的研究

    Institute of Scientific and Technical Information of China (English)

    刘子新

    2014-01-01

    With the development of economy and society, industrial electricity and electricity consumption are increasing;therefore, we must pay attention to the maintenance of high voltage transmission lines run management. Doing work related to the management, to ensure the normal operation of high voltage transmission lines, it is possible for the development of people's life, work and social economy to lay a good foundation.%随着经济社会的不断发展,工业用电和生活用电都在不断增加,所以,必须要重视高压输电线路的运行维护管理工作。做好相关的管理工作,确保高压输电线路的正常运行,能够为人们的生活、工作和社会经济的发展奠定良好的基础。

  18. On-line equalization for lithium-ion battery packs based on charging cell voltages: Part 1. Equalization based on remaining charging capacity estimation

    Science.gov (United States)

    Zheng, Yuejiu; Ouyang, Minggao; Lu, Languang; Li, Jianqiu; Han, Xuebing; Xu, Liangfei

    2014-02-01

    Because of the inevitable inconsistency during manufacture and use of battery cells, cell variations in battery packs have significant impacts on battery pack capacities, durability and safety for electric vehicles (EVs). To reduce cell variations and increase pack capacity, cell equalization is essentially required. In the series of two papers, we discover that dissipative cell equalization (DCE) using dissipative resistances is a feasible on-line equalization method for battery packs in EVs. We subsequently propose on-line equalization algorithms for lithium-ion battery packs based on charging cell voltage curves (CCVCs). The objective of these algorithms is to maximize pack capacities by conditioning CCVCs. As the first paper of the series, we first briefly review equalization topologies and algorithms. We discover cell remaining charging capacity (RCC) can be on-line estimated and further propose DCE algorithm based on remaining charging capacity estimation (RCCE). We establish a pack model with 8 cells in series and simulate 4 scenes with different cell variations. RCCE-DCE algorithm is proved to be effective by comparing pack capacities with/without RCCE-DCE algorithm. The equalization capability and over-equalization prevention are further examined, and the result shows that RCCE-DCE algorithm is suitable for on-line equalization in EVs.

  19. Separation sections AC 25kV/DC 1,5 kV in overhead contact lines of Netherlands' Railways; Trennstellen AC 25 kV/DC 1,5 kV im Oberleitungsnetz der Niederlaendischen Bahnen

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, G.; Roehlig, S. [Eisenbahn-Bundesamt, Dresden (Germany); Groeman, F.; Bogaerts, T. [KEMA Niederlande BV, Arnheim (Netherlands)

    2002-06-01

    At interfaces between traction energy supply systems, several and partly controversial requirements are encountered regarding the separation of line voltages, return currents, control of stray currents, control and command technology, length of trains and traffic technology. In Netherlands, local constraints forced to design very short transition sections at the separations of the high performance freight railway Betuweroute which becomes electrified with AC 25 kV 50 Hz against the existing contact line network operated with DC 1,5 kV. (orig.) [German] Schnittstellen zwischen Bahnstromversorgungssystemen stellen mehrere, teils gegensaetzliche Anforderungen hinsichtlich Trennung der Fahrleitungsspannungen und Rueckstroeme, Beherrschung von Streustroemen, Signal- und Sicherungstechnik, Zuglaengen und Verkehrstechnologie. Bei der mit AC 25 kV 50 Hz elektrifizierten Hochleistungs-Gueterbahn Betuweroute in den Niederlanden zwangen oertliche Gegebenheiten dazu, sehr kurze Trennstellen zum mit DC 1,5 kV betriebenen bestehenden Oberleitungsnetz zu entwickeln. (orig.)

  20. Current transformer verification system for in situ, live line end-to-end calibration of medium and high voltage current transformers

    Energy Technology Data Exchange (ETDEWEB)

    Gunn, C.; Irwin, L.; Marr, D. [Schneider Electric Canada, Toronto, ON (Canada)

    2007-07-01

    IEC Instrument Transformer Standard 60044-1 was created in response to recent industrial and regulatory trends for improved metering performance. The accuracy of high voltage (HV) metering depends on the quality of the instrument transformer signals feeding the energy meters. The complete current transformer (CT) system, including the end-to-end interconnection and metering burden, must be routinely verified in order to claim ongoing compliance. However, utilities rarely perform routine verification and calibration of medium voltage (MV) and HV current instrument transformers because of the complexities associated with CT primary circuit removal and subsequent primary injection. In some cases, routine verification and calibration is not performed due to the belief that conventional CT performance is a constant that never changes. However, conventional CT accuracies may change over time due to transformer insulation breakdown, electric field effects, core magnetization, and burden wiring effects. In addition, CT secondary circuits may be shared with multiple metering and protection devices that present a complex burden to the CT. Changes in burden impedance can also have an effect on CT accuracy. This paper presented the Current Transformer Verification System (CTVS), which provides a unique and novel means to precisely characterize and verify the actual end-to-end performance of MV and HV current transformers while still energized. The CTVS system takes into account any voltage or specific installed site burden dependency that may be present. It provides the utility with the ability to verify CTs in-situ without system interruption through live-line deployment and to readily check the accuracy of metering systems to ensure compliance with industry requirements. 2 tabs., 9 figs.

  1. Monitoring tumor motion with on-line mega-voltage cone-beam computed tomography imaging in a cine mode

    Energy Technology Data Exchange (ETDEWEB)

    Reitz, Bodo [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Gayou, Olivier [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Parda, David S [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Miften, Moyed [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States)

    2008-02-21

    Accurate daily patient localization is becoming increasingly important in external-beam radiotherapy (RT). Mega-voltage cone-beam computed tomography (MV-CBCT) utilizing a therapy beam and an on-board electronic portal imager can be used to localize tumor volumes and verify the patient's position prior to treatment. MV-CBCT produces a static volumetric image and therefore can only account for inter-fractional changes. In this work, the feasibility of using the MV-CBCT raw data as a fluoroscopic series of portal images to monitor tumor changes due to e.g. respiratory motion was investigated. A method was developed to read and convert the CB raw data into a cine. To improve the contrast-to-noise ratio on the MV-CB projection data, image post-processing with filtering techniques was investigated. Volumes of interest from the planning CT were projected onto the MV-cine. Because of the small exposure and the varying thickness of the patient depending on the projection angle, soft-tissue contrast was limited. Tumor visibility as a function of tumor size and projection angle was studied. The method was well suited in the upper chest, where motion of the tumor as well as of the diaphragm could be clearly seen. In the cases of patients with non-small cell lung cancer with medium or large tumor masses, we verified that the tumor mass was always located within the PTV despite respiratory motion. However for small tumors the method is less applicable, because the visibility of those targets becomes marginal. Evaluation of motion in non-superior-inferior directions might also be limited for small tumor masses. Viewing MV-CBCT data in a cine mode adds to the utility of MV-CBCT for verification of tumor motion and for deriving individualized treatment margins.

  2. Monitoring tumor motion with on-line mega-voltage cone-beam computed tomography imaging in a cine mode

    Science.gov (United States)

    Reitz, Bodo; Gayou, Olivier; Parda, David S.; Miften, Moyed

    2008-02-01

    Accurate daily patient localization is becoming increasingly important in external-beam radiotherapy (RT). Mega-voltage cone-beam computed tomography (MV-CBCT) utilizing a therapy beam and an on-board electronic portal imager can be used to localize tumor volumes and verify the patient's position prior to treatment. MV-CBCT produces a static volumetric image and therefore can only account for inter-fractional changes. In this work, the feasibility of using the MV-CBCT raw data as a fluoroscopic series of portal images to monitor tumor changes due to e.g. respiratory motion was investigated. A method was developed to read and convert the CB raw data into a cine. To improve the contrast-to-noise ratio on the MV-CB projection data, image post-processing with filtering techniques was investigated. Volumes of interest from the planning CT were projected onto the MV-cine. Because of the small exposure and the varying thickness of the patient depending on the projection angle, soft-tissue contrast was limited. Tumor visibility as a function of tumor size and projection angle was studied. The method was well suited in the upper chest, where motion of the tumor as well as of the diaphragm could be clearly seen. In the cases of patients with non-small cell lung cancer with medium or large tumor masses, we verified that the tumor mass was always located within the PTV despite respiratory motion. However for small tumors the method is less applicable, because the visibility of those targets becomes marginal. Evaluation of motion in non-superior-inferior directions might also be limited for small tumor masses. Viewing MV-CBCT data in a cine mode adds to the utility of MV-CBCT for verification of tumor motion and for deriving individualized treatment margins.

  3. Solid-state Marx based two-switch voltage modulator for the On-Line Isotope Mass Separator accelerator at the European Organization for Nuclear Research.

    Science.gov (United States)

    Redondo, L M; Silva, J Fernando; Canacsinh, H; Ferrão, N; Mendes, C; Soares, R; Schipper, J; Fowler, A

    2010-07-01

    A new circuit topology is proposed to replace the actual pulse transformer and thyratron based resonant modulator that supplies the 60 kV target potential for the ion acceleration of the On-Line Isotope Mass Separator accelerator, the stability of which is critical for the mass resolution downstream separator, at the European Organization for Nuclear Research. The improved modulator uses two solid-state switches working together, each one based on the Marx generator concept, operating as series and parallel switches, reducing the stress on the series stacked semiconductors, and also as auxiliary pulse generator in order to fulfill the target requirements. Preliminary results of a 10 kV prototype, using 1200 V insulated gate bipolar transistors and capacitors in the solid-state Marx circuits, ten stages each, with an electrical equivalent circuit of the target, are presented, demonstrating both the improved voltage stability and pulse flexibility potential wanted for this new modulator.

  4. Mechanics and pathomechanics in the overhead athlete.

    Science.gov (United States)

    Kibler, W Ben; Wilkes, Trevor; Sciascia, Aaron

    2013-10-01

    Optimal performance of the overhead throwing task requires precise mechanics that involve coordinated kinetic and kinematic chains to develop, transfer, and regulate the forces the body needs to withstand the inherent demands of the task and to allow optimal performance. These chains have been evaluated and the basic components, called nodes, have been identified. Impaired performance and/or injury, the DTS, is associated with alterations in the mechanics that are called pathomechanics. They can occur at multiple locations throughout the kinetic chain. They must be evaluated and treated as part of the overall problem. Observational analysis of the mechanics and pathomechanics using the node analysis method can be useful in highlighting areas of alteration that can be evaluated for anatomic injury or altered physiology. The comprehensive kinetic chain examination can evaluate sites of kinetic chain breakage, and a detailed shoulder examination can assess joint internal derangement of altered physiology that may contribute to the pathomechanics. Treatment of the DTS should be comprehensive, directed toward restoring physiology and mechanics and optimizing anatomy. This maximizes the body’s ability to develop normal mechanics to accomplish the overhead throwing task.

  5. Overhead analysis of universal concatenated quantum codes

    Science.gov (United States)

    Chamberland, Christopher; Jochym-O'Connor, Tomas; Laflamme, Raymond

    2017-02-01

    We analyze the resource overhead of recently proposed methods for universal fault-tolerant quantum computation using concatenated codes. Namely, we examine the concatenation of the 7-qubit Steane code with the 15-qubit Reed-Muller code, which allows for the construction of the 49- and 105-qubit codes that do not require the need for magic state distillation for universality. We compute a lower bound for the adversarial noise threshold of the 105-qubit code and find it to be 8.33 ×10-6. We obtain a depolarizing noise threshold for the 49-qubit code of 9.69 ×10-4 which is competitive with the 105-qubit threshold result of 1.28 ×10-3 . We then provide lower bounds on the resource requirements of the 49- and 105-qubit codes and compare them with the surface code implementation of a logical T gate using magic state distillation. For the sampled input error rates and noise model, we find that the surface code achieves a smaller overhead compared to our concatenated schemes.

  6. 基于广域测量系统的电压稳定指标%A On-Line Voltage Stability Index Based on Wide Area Measurement System

    Institute of Scientific and Technical Information of China (English)

    巩伟峥; 房鑫炎

    2011-01-01

    综述和比较了多种基于广域测量的在线电压静态稳定指标,通过理论分析指出了这几种指标的理论缺陷和使用限制.利用同步测量的母线电压相量、线路潮流等电气量,根据线路潮流电压方程计算比较线路两侧电压水平,提出了一种新的电压稳定性指标Ivs,指示被监测线路或母线的电压稳定情况.通过系统等效的方法解耦多机系统的线路电压耦合性,可将该指标推广到多机系统.在单机单负荷系统和IEEE 14节点系统的仿真表明,Ivs可以准确快速地判断系统线路电压稳定情况,预测线路电压失稳点,且适用于所有种类的线路.与之前的电压静态稳定指标相比,Ivs具有无需判断线路电阻,物理概念清晰,适用范围广,线性度好等优点,有利于实现在线电压稳定监测和评估.%On-line steady state voltage stability indices based on wide area measurement system (WAMS) are summarized and compared. Based on theoretical analysis, the theoretical defects and usage limitations of these indices are pointed out. Utilizing synchronously measured electric quantities such as bus voltage phasors and line power flows and according to the comparison results of voltage levels, which are calculated by power flow and voltage equations of transmission line, at both terminals oftransmission lines, a new voltage stability index Ivs is proposed to indicate the voltage stability condition of monitored bus or transmission line. By means of system equivalence, the coupling of line voltage in multi-machine power system is decoupled, thus the proposed voltage stability index can be applied to multi-machine power system. Simulation results fiom single-machine single-load system and IEEE 14-bus system show that voltage stability condition of transmission line can be rapidly judged and the voltage instability point can be predicted by the proposed index IVS, and the proposed index is suitable to all kinds of transmission

  7. Evaluation and measurement of magnetic field exposure at a typical high-voltage substation and its power lines.

    Science.gov (United States)

    Ozen, S

    2008-01-01

    This study presents a survey of magnetic field measurements including those resulting from 380/154 kV power substations, which play a vital role in human body biological studies. The survey was carried out in the main power substation of Antalya, Turkey, located at the suburban region of the city, under actual loads. The paper also presents the actual magnetic field strength measured near the 380/154 kV substation and power transmission lines (380 and 154 kV) connecting to the substation. Since most part of these lines pass through a residential area, they have been included in the study, and the actual magnetic field variation around them has been investigated by comparative analysis of measured data. For the occupants working at substations, occupational exposure has been analysed with actual magnetic fields at operating locations. Induced internal electric fields and current densities in the occupants' body due to exposure to external magnetic fields produced by a conventional 380/154 kV power substation have been investigated.

  8. Steady state tests of high voltage ceramic feedthroughs and co-axial transmission line of ICRF heating system for the Large Helical Device

    Energy Technology Data Exchange (ETDEWEB)

    Mutoh, Takashi; Kumazawa, Ryuhei; Seki, Tetsuo; Simpo, Fujio; Nomura, Goro; Ido, Tsuyoshi; Watari, Tetsuo [National Inst. for Fusion Science, Toki, Gifu (Japan); Norterdaeme, J.M.

    1998-06-01

    Steady state ICRF heating technologies have been developed to heat plasma for more than 30 minutes in the LHD. Steady state operation tests of high voltage up to 40 kV{sub OP} for more than 30 minutes were carried out on the RF vacuum feedthroughs and the co-axial transmission line in the test set. Four types of ceramic feedthroughs each having a diameter of 240 mm were tested. The cone-type alumina ceramic and the cylinder-type silicon nitride composite-ceramic feedthroughs produced good performances of 40 kV/30 minutes and 50 kV/10 seconds. The others had vacuum leaks when subjected to a long pulse duration. The temperature of the cone-type alumina ceramic feedthrough was measured during the ICRF operations. By using gas-cooling techniques, the temperature increase of the ceramic was substantially reduced and saturated within 20 minutes. Without gas-cooling, the temperature increased linearly and did not saturated. So, this approach could not be used for steady state. The RF dissipation on the ceramic was calculated using the finite element computer code (ANSYS). It was found that damaged feedthroughs had local high heat spots, which could result in vacuum leaks. A water-cooled co-axial transmission line of 240 mm diameter was designed and tested. The specially designed connector components and Teflon insulator disks were tested. During the test, the insulation gases of nitrogen, sulfur hexafluoride and carbon dioxide were used to compare the capability of insulation for steady state. For the duration of a 10-second pulse, these gases performed well up to 60 kV{sub OP}. However, for steady state operation, carbon dioxide gas could not withstand voltages above 40 kV{sub OP}. The connector components of the transmission line performed without problems below 50 kV{sub OP} and 1 kA{sub OP} for a 30-minute operation. The performance of the feedthroughs and transmission line exceeded the specifications for steady state heating in the LHD. (J.P.N.)

  9. Full-Wave Analysis of Field-to-Line Coupling Effects Using 1D FDTD Method under Exciting Source with Different Bandwidths

    Directory of Open Access Journals (Sweden)

    Qi Zhang

    2014-01-01

    Full Text Available With the aim to analyze field-to-line coupling effects based on energy spectrum, parallel finite-difference time-domain (FDTD method is applied to calculate the induced voltage on overhead lines under high-power electromagnetic (HPEM environment. Firstly, the energy distribution laws of HEMP (IEC 61000-2-9, HEMP (Bell Laboratory, HEMP (Paulino et al., 2010, and LEMP (IEC61000-4-5 are given. Due to the air-earth stratified medium, both the absorbing boundary and the connecting boundary applied to scattering by finite-length objects are separately set in aerial and underground parts. Moreover, the influence of line length on induced voltage is analyzed and discussed. The results indicate that the half-peak width is wider with the increase of the line length. But the steepness of induced voltage on the overhead line is invariable. There is no further increase in the peak of induced voltage especially when the line length increases to be equivalent to the wavelength of the frequency bands with the maximum energy.

  10. Synthesis of MnO2 nanoparticles and their effective utilization as UV protectors for outdoor high voltage polymeric insulators used in power transmission lines.

    Science.gov (United States)

    Ghosh, Dipankar; Bhandari, Subhendu; Khastgir, Dipak

    2016-12-07

    Polymeric outdoor insulators derived from polydimethyl siloxane (PDMS) are replacing conventional ceramic insulators in high voltage power transmission lines because of their improved electrical, mechanical and hydrophobic performance. Major impediments like failure of polymeric insulators due to natural aging by UV radiation from sunlight and electrical tracking have limited their usage. Herein, it is demonstrated about the usage of manganese dioxide based nanoparticles as an effective agent to prevent the UV accelerated aging of polymeric insulators. MnO2 nanoparticles of different shapes and dimension were synthesized using a single step wet chemical reaction between KMnO4 and methyl acetate. Namely, 2D δ-MnO2 nanosheets, 1D α-MnO2 nanowires and 3D α-MnO2 nanorods were formed. These nanoparticles were extensively characterized by various techniques. In the scope of the study, the δ-MnO2 (10(-5) S cm(-1); 1 MHz) nanosheet demonstrated the lowest electrical AC conductivity and a higher band gap compared to the 1D (10(-4) S cm(-1); 1 MHz) and 3D variety (10(-4) S cm(-1); 1 MHz). Owing to the lower electrical conductivity of the δ-MnO2 nanosheet, it was further incorporated at different filler volumes in the polymeric matrix (blend of polydimethyl siloxane/ethylene vinyl acetate) as a UV protector material for the polymer based high voltage composite polymeric insulator. The UV protection ability, induced by the δ-MnO2 nanosheet, was achieved without adversely affecting other properties of the formulated insulator compound material. The optimum properties of the composite were found to be obtained at 3 phr (three parts of δ-MnO2 nanosheet per hundred parts of polymer) loading of the nanosheet. The current work will promise to pave a new pathway for the generation of UV resistant high voltage power transmission line insulator materials. It would be interesting in the future to study the effect of incorporation of manganese dioxide based nanosheets on the UV

  11. Memory loss risk assessment for the students nearby high-voltage power lines-a case study.

    Science.gov (United States)

    Ghadamgahi, Mojgan; Monazzam, Mohammad Reza; Hosseini, Monireh

    2016-06-01

    With increasing sources of alternating current electromagnetic fields (EMFs) in everyday life, their possible harmful effects on human health are a main area of concern in many countries. Given that children are the most valuable assets of each country, it is of utmost importance to study the effect(s) of EMF exposure on various health aspects of members within this age group. The present research is the first systematic study of the effects of exposure to electric substations on the memory status of male students in the age group of 10 to 12 years. The flux density values of extremely low frequency magnetic field were measured at four elementary schools in Tehran in accordance with IEEE std 644-1994. The device was 3-axis (X, Y, and Z) Gauss Meter, model: TES-1394. The students from two schools nearby a high voltage electricity substation (at distances of 30 and 50 m) were selected as the exposed group, and the students of two other schools at further distances of 1390 and 610 m were considered as the control group. To determine the status of working memory in the students, the questionnaire was adapted from Wechsler Intelligence Scale for Children (WISC-IV). The completed questionnaires were analyzed by t test and chi-square using SPSS 20. The average magnetic flux density was 0.245 μT at case schools and 0.164 μT at control schools, P < 0.01. The demographic characteristics of the students in the two groups were not statistically different. However, the difference in working memory was significant at the level of 5 %. The results of the questionnaire data showed that students in the control group had better working memory compared to students in case group. The findings revealed a reverse correlation between magnetic flux density and working memory of students (R = -0.255). It is concluded that extremely low frequency magnetic field exposure may have a negative impact on the working memory of children, but further studies are necessary to reach a

  12. Voltage surges induced in transformer secondaries with loads characterized by sensitive electronic equipment

    Energy Technology Data Exchange (ETDEWEB)

    Cogo, Joao Roberto [GSI Engenharia e Consultoria Ltda., Taubate, SP (Brazil)], Email: gsi@gsiconsultoria.com.br; Dommel, Hermann Wilhelm [University of British Columbia, Vancouver (Canada)], Email: hermannd@ece.ubc.ca

    2007-07-01

    The grounding of sensitive electronic equipment such as computers, programmable logic controllers (PLC), process control systems, and other electronic equipment is one of the most important considerations towards obtaining an efficient operation of such systems. Such equipment, which for the purposes of this work is called 'Sensitive Electronic Equipment - SEE' is very sensitive to faults and low intensity random voltages which have no effect upon the electrical power equipment and upon human beings. In this work, the grounding problem is evaluated, to guide the user on the proper installation of SEEs, so as to prevent them from being damaged. The following items will be discussed: voltages which SEEs are subject to during incidence of atmospheric surges in the distribution overhead lines to which they are connected; sustained voltage that the high voltage supply of SEEs must be able to withstand during line-to-ground faults that originate from atmospheric surges that reach the transmission lines which are connected to the electrical power self producers (or electrical power independent producers). (author)

  13. Research on the Error Characteristics of a 110 kV Optical Voltage Transformer under Three Conditions: In the Laboratory, Off-Line in the Field and During On-Line Operation

    Directory of Open Access Journals (Sweden)

    Xia Xiao

    2016-08-01

    Full Text Available Optical voltage transformers (OVTs have been applied in power systems. When performing accuracy performance tests of OVTs large differences exist between the electromagnetic environment and the temperature variation in the laboratory and on-site. Therefore, OVTs may display different error characteristics under different conditions. In this paper, OVT prototypes with typical structures were selected to be tested for the error characteristics with the same testing equipment and testing method. The basic accuracy, the additional error caused by temperature and the adjacent phase in the laboratory, the accuracy in the field off-line, and the real-time monitoring error during on-line operation were tested. The error characteristics under the three conditions—laboratory, in the field off-line and during on-site operation—were compared and analyzed. The results showed that the effect of the transportation process, electromagnetic environment and the adjacent phase on the accuracy of OVTs could be ignored for level 0.2, but the error characteristics of OVTs are dependent on the environmental temperature and are sensitive to the temperature gradient. The temperature characteristics during on-line operation were significantly superior to those observed in the laboratory.

  14. Research on the Error Characteristics of a 110 kV Optical Voltage Transformer under Three Conditions: In the Laboratory, Off-Line in the Field and During On-Line Operation.

    Science.gov (United States)

    Xiao, Xia; Hu, Haoliang; Xu, Yan; Lei, Min; Xiong, Qianzhu

    2016-01-01

    Optical voltage transformers (OVTs) have been applied in power systems. When performing accuracy performance tests of OVTs large differences exist between the electromagnetic environment and the temperature variation in the laboratory and on-site. Therefore, OVTs may display different error characteristics under different conditions. In this paper, OVT prototypes with typical structures were selected to be tested for the error characteristics with the same testing equipment and testing method. The basic accuracy, the additional error caused by temperature and the adjacent phase in the laboratory, the accuracy in the field off-line, and the real-time monitoring error during on-line operation were tested. The error characteristics under the three conditions-laboratory, in the field off-line and during on-site operation-were compared and analyzed. The results showed that the effect of the transportation process, electromagnetic environment and the adjacent phase on the accuracy of OVTs could be ignored for level 0.2, but the error characteristics of OVTs are dependent on the environmental temperature and are sensitive to the temperature gradient. The temperature characteristics during on-line operation were significantly superior to those observed in the laboratory.

  15. Research on the Error Characteristics of a 110 kV Optical Voltage Transformer under Three Conditions: In the Laboratory, Off-Line in the Field and During On-Line Operation

    Science.gov (United States)

    Xiao, Xia; Hu, Haoliang; Xu, Yan; Lei, Min; Xiong, Qianzhu

    2016-01-01

    Optical voltage transformers (OVTs) have been applied in power systems. When performing accuracy performance tests of OVTs large differences exist between the electromagnetic environment and the temperature variation in the laboratory and on-site. Therefore, OVTs may display different error characteristics under different conditions. In this paper, OVT prototypes with typical structures were selected to be tested for the error characteristics with the same testing equipment and testing method. The basic accuracy, the additional error caused by temperature and the adjacent phase in the laboratory, the accuracy in the field off-line, and the real-time monitoring error during on-line operation were tested. The error characteristics under the three conditions—laboratory, in the field off-line and during on-site operation—were compared and analyzed. The results showed that the effect of the transportation process, electromagnetic environment and the adjacent phase on the accuracy of OVTs could be ignored for level 0.2, but the error characteristics of OVTs are dependent on the environmental temperature and are sensitive to the temperature gradient. The temperature characteristics during on-line operation were significantly superior to those observed in the laboratory. PMID:27537895

  16. DILATE, UNA HERRAMIENTA DE CÓMPUTO PARA EL DISEÑO DE LÍNEAS AÉREAS DE TRANSMISIÓN DE ENERGÍA ELÉCTRICA DILATE, A COMPUTER TOOL FOR DESIGN OF POWER OVERHEAD TRANSMISSION LINES

    Directory of Open Access Journals (Sweden)

    César A Becerra C

    2007-08-01

    Full Text Available En este artículo se presenta una herramienta computacional de carácter académico y de libre distribución llamada DILATE, desarrollada en Microsoft® Excel empleando Visual Basic® para Aplicaciones (VBA, a través de la cual se facilita el diseño de líneas aéreas trifásicas de transmisión de energía eléctrica. DILATE integra tres módulos principales: cálculo eléctrico, cálculo mecánico y proceso de plantillado; este último se realiza directamente sobre la representación gráfica del perfil longitudinal del terreno, el cual es importado desde un archivo con extensión DXF. El resultado es una herramienta computacional que se encarga ágilmente de todos los procesos de cálculo y actualización de resultados, disminuyendo de esta manera el tiempo de diseño y los posibles errores que podrían cometerse en un procedimiento manual. La labor del diseñador se centra en la entrada de datos y el análisis de resultados a través de su amigable interfaz de usuario.In this article, a free distribution computational tool for academic use called DILATE is presented. The tool was developed using Microsoft® Excel using Visual Basic® for Applications (VBA, which facilitates the design of three-phase overhead transmission lines. DILATE integrates three principal calculation modules: electrical calculation, mechanical calculation, and tower spotting and transmission line alignment: the latter is done directly on the graphical representation of the longitudinal profile of the land, imported from a DXF file. The result is a computational tool that helps with all the processes of calculation and updating of results, reducing the time spent in the design and the possible errors that could arise from a manual procedure. The designer's work is focused on the data input and the results analysis through its user friendly interface.

  17. 高压输电线路设备红外诊断与检测技术分析%Analysis of high voltage transmission line equipment of infrared diagnosis and detection technology

    Institute of Scientific and Technical Information of China (English)

    罗昳昀

    2013-01-01

    近年来,电力项目工程规模不断扩大,高压输电线路设备也在不断完善,输电线路设备红外诊断在高压输电中的应用,极大地提升了高压输电线路维护工作的质量和效率。本文主要介绍高压输电线路设备红外诊断与检测原理,同时还分析了设备故障发热对高压输电线路的危害,然后介绍了几种高压输电线路红外诊断与检测技术,希望能帮助相关工作人员提升工作质量和效率。%In recent years,the electric power project of the expanding scale,high voltage transmission line equipment is being perfected,application of electric equipment of infrared diagnosis in high voltage power transmission line in high voltage transmission line,improve work great maintenance work quality and efficiency.This paper mainly introduces the high voltage transmission line equipment of infrareddiagnosis and detection principle,and also analyses the harm of equipment fault heating on high voltage transmission line,and then introducedthe infrared detection and diagnosis technology of high voltage transmission line, the hope can help staff to improve work quality and efficiency.

  18. 基于UV检测的UHV输电线路起晕电压的试验研究%Test Study on Corona Onset Voltage of UHV Transmission Lines Based on UV Detection

    Institute of Scientific and Technical Information of China (English)

    刘云鹏; 王会斌; 陈维江

    2008-01-01

    Corona discharge is being detected by UV imaging detection technology at home and abroad in recent years. This technology is used in the corona tests of conductor bundles in this paper. In order to further research the corona characteristic, optimize geometry parameters and diameter of sub-conductor, and increase corona onset voltage of transmission lines, corona tests of three model conductors which are placed inside the outdoor corona cage are conducted. Corona cage could be used to simulate the corona activities on transmission lines under a low voltage and different conditions in an effective and economical way. Photon which was created by UV light as a result of corona discharge on conductors is detected by the UV detection apparatus. The photon number within unit interval, namely photon counting rate is adopted as the parameter of quantifying the intensity of corona discharge. According to the apparent change of photon number, corona onset voltage can be judged. All tests are conducted under almost same atmosphere condition. Using the method, corona onset voltage is acquired. The results indicate that the tests have a good repeatability, in other words, repeating same test twice same result can be aquired. The corona onset voltage can be acquired exactly from the curve of applied voltage vs. photon counting rate. Therefore UV detection apparatus can not only used to find discharge point exactly, but also applied on corona discharge research and live detection for power equipments. The method using in this paper is proved that is a new available method.

  19. Geography via the Overhead Projector: Do It This Way, 7.

    Science.gov (United States)

    Best, Thomas D.

    This booklet is designed to assist teachers in their use of overhead projectors when teaching geography. With the overhead technique, relationships among patterns can be suggested bit by bit on inexpensive, easily prepared overlays that are projected to sizes appropriate for a particular instructional situation. A general discussion of the…

  20. 环境温度对架空导线用碳纤维复合芯成型工艺及性能的影响%EFFECT OF AMBIENT TEMPERATURE ON FORMING PROCESS AND PERFORMANCE OF CARBON FIBER REINFORCED COMPOSITE CORE USED FOR OVERHEAD TRANSMISSION LINE

    Institute of Scientific and Technical Information of China (English)

    何州文; 陈新; 药宁娜

    2011-01-01

    The ambient temperature-viscosity relation and the gelation time-temperature relation of two resin system were studied, then the resin system used for pulltrusion molding was confirmed. Carbon fiber reinforced composite core used for overhead transmission line was prepared by using the confirmed resin system, the effects of ambient temperature on forming process and tensile property of carbon fiber reinforced composite core were analyzed and the tensile fracture mechanism of the carbon fiber reinforced composite core was analyzed by SEM. The results showed lhat ambient temperalure had great influence on tensile property and surface per-formance of carbon fiber reinforced composite core. If pulltrusion parameters weren't timely adjusted when ambient temperature changed greatly, the defect of composite core would appeared, such as instance die blocked, whiting, cavity. When ambient temperature was 30℃ , the composite core had highest tensile strength.%研究了两种不同树脂体系黏度与环境温度、凝胶化时间与温度的关系,确定了用于拉挤工艺的树脂体系.采用该树脂体系制备了架空导线用碳纤维复合芯,分析了环境温度对碳纤维复合芯制品成型工艺和拉伸强度的影响,采用扫描电子显微镜分析了碳纤维复合芯的拉伸断裂机理.结果表明,环境温度对碳纤维复合芯的拉伸强度及表现性能影响较大,当环境温度变化较大时如不及时调整成型工艺参数,复合芯制品会出现堵模、白粉、沟痕等缺陷:当环境温度为30C时复合芯制品拉伸强度最高.

  1. Assessment of personal noise exposure of overhead-traveling crane drivers in steel-rolling mills

    Institute of Scientific and Technical Information of China (English)

    ZENG Lin; CHAI Dong-liang; LI Hui-juan; LEI Zhuo; ZHAO Yi-ming

    2007-01-01

    Background Noise is widespread occupational hazard in iron and steel industry. Overhead-traveling cranes are widely used in this industry, but few studies characterized the overhead-traveling crane drivers' noise exposure level so far. In this study, we assessed and characterized personal noise exposure levels of overhead-traveling crane drivers in two steel-rolling mills.Methods One hundred and twenty-four overhead-traveling crane drivers, 76 in the cold steel-rolling mill and 48 in the hot steel-rolling mill, were enrolled in the study. Personal noise dosimeters (AIHUA Instruments Model AWA5610e,Hangzhou, China) were used to collect full-shift noise exposure data from all the participants. Crane drivers carried dosimeters with microphones placed near their collars during the work shifts. Work logs had been taken by the drivers simultaneously. Personal noise exposure data were divided into segments based on lines in which they worked. All statistical analyses were done using SPSS 13.0.Results The average personal noise exposure (LAeq.8h) of overhead-traveling crane drivers in the hot steel-rolling mills ((85.03±2.25) dB(A)) was higher than that in the cold one ((83.05±2.93) dB(A), P<0.001). There were 17 overhead traveling cranes in the hot steel-rolling mill and 24 cranes in the cold one, of which carrying capacities varied from 15 tons to 100 tons. The average noise exposure level based on different lines in the hot and cold steel-rolling mills were (85.2±2.61) dB(A) and (83.3±3.10) dB(A) respectively (P=0.001), which were similar to the average personal noise exposure in both mills. The noise exposure levels were different among different lines (P=0.021).Conclusion Noise exposure levels, depending upon background noise levels and the noise levels on the ground, are inconstant. As the noise exposure levels are above the 85 dB(A) criteria, these drivers should be involved in the Hearing Conservation Program to protect their hearing.

  2. Testing of long-flashover arresters designed for distribution lines

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Filho, Orsino; Mello, Darcy Ramalho de; Oliveira, Gloria Suzana Gomes de [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)], Emails: orsino@cepel.br, darcy@cepel.br, gloria@cepel.br; Podporkin, Georgij; Wey, Acacio [Streamer Electric Company (Russian Federation)], E-mails: georgij.podporkin@streamer.ru, acacio.wey@bighost.com.br

    2007-07-01

    Outages of overhead power lines due to lightning strokes are one of the main causes of shortages of electric supplies and economic losses of power utilities. Pole-top metal oxide arresters can protect distribution lines against induced over-voltages, but they can be destroyed in case of direct lightning stroke. Long Flashover Arresters (LFAs) have been developed and used successfully for this purpose and have no possibility of being destroyed because the current flows externally along its surface. Since field experience with 10 kV LFAs has been very successful, it was decided to work on developing 13.8 kV LFAs, considering that it is the predominant voltage level of overhead distribution lines in Brazil and other countries. The performance of LFA for quenching and dielectric tests has been investigated through laboratory tests under conditions that typically represent electrical energy distribution systems. Details about these tests and their results are presented in this paper. Information about their design and applications are also shortly presented (author)

  3. 高压线除冰机器人本体结构设计%Design of Body Structure for a Deicing Robot on the High Voltage Line

    Institute of Scientific and Technical Information of China (English)

    林坚磊; 刘文华; 陈雪; 侯智强; 宋赫

    2015-01-01

    Aiming at icing conditions of high voltage lines, a kind of line deicing robot is proposed. It consists of moving mechanism, climbing obstacle structure, deicing hammer, gear drive and camera system. The robot utilizes the deicing wheel fixed in the fore-end to cut ice, and then the deicing hammer clears up the remaining icing. The driving wheel adopts semi-circular structure to meet a range of diameter and uses a locking mechanism to provide stability for the robot. The robot is of small size and with high efficiency deicing, and cleared icing thickness can reach from10 to 25mm.%针对高压输电线路的覆冰情况,提出了一种线路除冰机器人,该机器人由行走机构、越障机构、除冰工具、传动系统和摄像系统组成。机器人利用固定在前端的除冰砂轮对覆冰切割,而后除冰锤实现180°半圆形往复运动对剩余覆冰进行反复敲打清除;驱动轮采用半圆型结构,适应一定范围的线径,为机器人提供了稳定性。该机器人体积小,除冰效率高,可清除厚度为10~25 mm的覆冰。

  4. A low-latency, low-overhead encoder for data transmission in the ATLAS Liquid Argon Calorimeter trigger upgrade

    Science.gov (United States)

    Xiao, Le; Li, Xiaoting; Gong, Datao; Chen, Jinghong; Deng, Binwei; Fan, Qingjun; Feng, Yulang; Guo, Di; He, Huiqin; Hou, Suen; Huang, Guangming; Liu, Chonghan; Liu, Tiankuan; Sun, Xiangming; Tang, Yuxuan; Teng, Ping-Kun; Vosooghi, Bozorgmehr; Xiang, Annie C.; Ye, Jingbo; You, Yang; Zuo, Zhiheng

    2016-09-01

    In this paper, we present the design and test results of an encoder integrated circuit for the ATLAS Liquid Argon Calorimeter trigger upgrade. The encoder implements a low-latency and low-overhead line code called LOCic. The encoder operates at 320 MHz with a latency of no greater than 21 ns. The overhead of the encoder is 14.3%. The encoder is an important block of the transmitter ASIC LOCx2, which is prototyped with a commercial 0.25 μm Silicon-on-Sapphire CMOS technology and packaged in a 100-pin QFN package.

  5. Insulated DC-to-DC converter with wide input voltage range; Convertisseur continu-continu isole a large plage de tension d'entree: conception d'une alimentation 36 kW pour auxiliaire ferroviaire

    Energy Technology Data Exchange (ETDEWEB)

    Rieux, O.

    2000-11-15

    This thesis presents the research that has been carried out in the context of a collaboration contract between the FAIVELEY Transport company and the laboratoire d'Electrotechnique et d'Electronique Industrielle Laboratory. The goal of this research is the study of a converter that feeds a railway air conditioning unit, and that is fed by the overhead line voltage. It is an insulated DC-to-DC converter, of which input voltage varies from 2 to 5 kV, and output voltage is 600 V. This document introduces and justifies an original energy conversion principle. This principle is based on a series association of ZVS inverters, and a co-ordinated control that takes up the input voltage variations. This document also exposes detailed operation, and design rules applicable to converters based on this principle. Related studies are presented too, on such subjects as in situ reconnection of inverters for adapting to other overhead line types, or fault tolerance. Operation of such a converter has been studied by simulation, thus validating both the topology and the control modes. Experiments have also been carried out to check feasibility of a critical component of the structure: the saturable inductor. (author)

  6. 智能电网下低压电力线通信的特性研究%Study on Communication Characteristic of Low Voltage Electric Power Lines in Smart Grid

    Institute of Scientific and Technical Information of China (English)

    邵昱; 李晨; 王超; 王珏; 闫帅榜

    2014-01-01

    提出智能电网环境下的通信方式,并说明低压电力线通信的优点。研究分析了低压电力线通信的时变性、深衰减、多径性、电磁干扰等特点。在分析电力载波通信(power line communication,PLC)原理及特点的基础上,提出利用正交频分复用(orthogonal frequency division multiplexing,OFDM)技术来提高系统的传输性能。对智能电网环境下低压电力线通信技术的应用进行展望,并列举低压电力线通信在超远程抄表、网络连接等方面的应用。%This paper proposes a kind of communication way under the background of smart grid and explains merits of low voltage electric power line communication.It studies and analyzes time-varying characteristic,deep attenuation,multipath characteristic and electromagnetic interference of low voltage electric power line communication.On the basis of analyzing power line communication principles and features,it proposes to use orthogonal frequency division multiplexing technology to improve transmission performance of the system.In addition,it looks into distance application of low voltage electric power line communication technology under the background of smart grid and enumerates application cases of low voltage e-lectric power line communication in extra long distance meter reading,network connection,and so on.

  7. High Voltage Distribution

    Science.gov (United States)

    Norbeck, Edwin; Miller, Michael; Onel, Yasar

    2010-11-01

    For detector arrays that require 5 to 10 kV at a few microamps each for hundreds of detectors, using hundreds of HV power supplies is unreasonable. Bundles of hundreds of HV cables take up space that should be filled with detectors. A typical HV module can supply 1 ma, enough current for hundreds of detectors. It is better to use a single HV module and distribute the current as needed. We show a circuit that, for each detector, measures the current, cuts off the voltage if the current exceeds a set maximum, and allows the HV to be turned on or off from a control computer. The entire array requires a single HV cable and 2 or 3 control lines. This design provides the same voltage to all of the detectors, the voltage set by the single HV module. Some additional circuitry would allow a computer controlled voltage drop between the HV and each individual detector.

  8. Development of a Lightweight, High-speed Obstacle Negotiating Robot for Line-tracking and Deicing along High Voltage Power Transmission Lines%轻量化高速过障高压巡线除冰机器人研制

    Institute of Scientific and Technical Information of China (English)

    翁盛槟; 聂晓根; 黄博贤; 谢招龙

    2016-01-01

    ln order to solve the problem of thick and solid icing on the power transmission lines in the cold zone, a strong and effi-cient deicing robot is developed. The robot is lightweight, high-speed, obstacle negotiating and fit to work along the high voltage power transmission lines in the cold zone. Adopting mil ing and pressing, the robot can deice efficiently. With the flexible lateral wheel driving device, the robot can operate stably and cross obstacles at high speed. By dynamic analysis, the structure of the robot is op-timized, and is lightweight. ln this paper, the working principles, mechanical structure, power system and control system are dis-cussed. The operation of the prototype verified the design.%针对严寒地带输电线路覆冰厚实的情况,以强力高效除冰、高速过障和轻量化为目标,研制一种适合严寒地带高压输电线除冰机器人。该机器人采用铣削和压除组合方式实现强力、高效除冰,设计柔性侧向轮驱动装置实现机器人稳定运行和高速过障,通过对除冰机器人进行动力学分析实现结构优化和轻量化。并论述该除冰机器人的工作原理、机械结构、动力系统和控制系统,样机运行结果验证了设计的正确性。

  9. Line-grasping Control for the Deicing Robot on High Voltage Transmission Line%高压输电线路除冰机器人抓线运动控制

    Institute of Scientific and Technical Information of China (English)

    王聪; 孙炜

    2011-01-01

    针对高压输电线路除冰机器人越障抓线过程中存在的对输电线缆定位困难的问题,提出一种基于输电线缆几何特征的单目立体视觉定位方法.该方法根据输电线缆成像的边缘、输电线缆半径和摄像机成像模型,可以计算输电线缆中轴线在摄像机坐标系下的数学表达式,从而对任意位姿的高压输电线缆进行精确的三维定位.在输电线缆准确定位的基础上,为了快速地确定抓取输电线缆的准确位置并提高除冰机器人抓线运动控制实时性,提出一种基于除冰机器人机械臂结构特征的除冰机器人抓线运动控制策略,该控制策略通过在机器人基坐标系下计算机械臂末端夹持器工作空间曲面与输电线缆轴线的交点来确定抓取点,并同时计算抓取线缆时机械臂各个关节的期望位置.试验结果验证了所提视觉定位方法及抓线控制策略的有效性.%To solve the visual positioning problem of the deicing robot working on high voltage transmission line, a monocular stereoscopic visual positioning method based on the geometrical feature of the transmission cable is presented.On the basis of the edge of transmission cable image, the radius of transmission cable and the camera imaging model, this method deduces the mathematic formula of transmission cable axis under the camera coordinate system, so that the precision 3D positioning of the HV transmission cable in arbitrary pose can be realized.In order to solve the difficulty of calculating the line-grasping point and meet the real time requirement of line-grasping control, a line-grasping control scheme based on the mechanical structure of the deicing robot manipulator is developed.By calculating the intersection point of the transmission cable axis and the end-effector workspace of the deicing robot under deicing robot base coordinate system, this control scheme determines the coordinate of the line-gasping point and the desired

  10. A low-latency, low-overhead encoder for data transmission in the ATLAS Liquid Argon Calorimeter trigger upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Le [Department of Physics, Central China Normal University, Wuhan, Hubei 430079 (China); Department of Physics, Southern Methodist University, Dallas, TX 75275 (United States); Li, Xiaoting [Department of Physics, Central China Normal University, Wuhan, Hubei 430079 (China); Gong, Datao, E-mail: dgong@mail.smu.edu [Department of Physics, Southern Methodist University, Dallas, TX 75275 (United States); Chen, Jinghong [Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77004 (United States); Deng, Binwei [School of Electric and Electronic Information Engineering, Hubei Polytechnic University, Huangshi, Hubei 435003 (China); Fan, Qingjun; Feng, Yulang [Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77004 (United States); Guo, Di [Department of Physics, Southern Methodist University, Dallas, TX 75275 (United States); State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); He, Huiqin [Department of Physics, Central China Normal University, Wuhan, Hubei 430079 (China); Department of Physics, Southern Methodist University, Dallas, TX 75275 (United States); Shenzhen Polytechnic, Shenzhen 518055 (China); Hou, Suen [Institute of Physics, Academia Sinica, Nangang 11529, Taipei, Taiwan (China); Huang, Guangming, E-mail: gmhuang@phy.ccnu.edu.cn [Department of Physics, Central China Normal University, Wuhan, Hubei 430079 (China); Liu, Chonghan; Liu, Tiankuan [Department of Physics, Southern Methodist University, Dallas, TX 75275 (United States); Sun, Xiangming [Department of Physics, Central China Normal University, Wuhan, Hubei 430079 (China); Tang, Yuxuan [Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77004 (United States); Teng, Ping-Kun [Institute of Physics, Academia Sinica, Nangang 11529, Taipei, Taiwan (China); and others

    2016-09-21

    In this paper, we present the design and test results of an encoder integrated circuit for the ATLAS Liquid Argon Calorimeter trigger upgrade. The encoder implements a low-latency and low-overhead line code called LOCic. The encoder operates at 320 MHz with a latency of no greater than 21 ns. The overhead of the encoder is 14.3%. The encoder is an important block of the transmitter ASIC LOCx2, which is prototyped with a commercial 0.25 μm Silicon-on-Sapphire CMOS technology and packaged in a 100-pin QFN package. - Highlights: • We present the design and test results of an encoder integrated circuit for the ATLAS Liquid Argon Calorimeter trigger upgrade. • The encoder implements a low-latency and low-overhead line code called LOCic. The encoder operates at 320 MHz with a latency of no greater than 21 ns. The overhead of the encoder is 14.3%. • The encoder is an important block of the transmitter ASIC LOCx2, which is prototyped with a commercial 0.25 μm Silicon-on-Sapphire CMOS technology for radiation-tolerance and packaged in a 100-pin QFN package.

  11. 输电高压线路的检测与维护技术分析%Analysis on the Detection and Maintenance Technology of High Voltage Transmission Line

    Institute of Scientific and Technical Information of China (English)

    于洪召

    2015-01-01

    High-voltage transmission line, as an important component of the power grid, shoulders the responsibility of grid electricity transmission, so its health condition has an important influence to the safe and stable operation of power grid. In this paper, the content and techniques of the detection and maintenance of the high voltage transmission line are discussed, in order to provide reference for repair and maintenance of high voltage transmission lines.%输电高压线路作为电网的重要组成部分,担负着电网电能的传输重任,其健康状况对电网的安全稳定运行有着重要的影响。本文对输电高压线路检修与维护的内容和技术进行了探讨,以期为高压输电线路的检修与维护能够发挥积极的借鉴作用。

  12. 浅谈高压输电线路的运行维护与防雷措施%On the Running Maintenance and Lightning Protection Measures of High-voltage Transmission Line

    Institute of Scientific and Technical Information of China (English)

    赵登

    2014-01-01

    高压输电线路是电力系统的重要组成部分。由于地形复杂、距离长,高压输电线路在运行过程中难免出现故障,本文针对高压输电线路常见的故障,提出了有效的故障诊断和处理方法,为线路故障的诊断和维护提供了依据,具有重要的理论和实用价值。%The high-voltage transmission line is an important part of the power system. Because of the complex terrain and long distance, high-voltage transmission line will inevitably fail during operation. Aiming at the common faults of high-voltage transmission line, this paper proposes effective fault diagnosis and treatment methods, which provide basis, for fault diagnosis and maintenance and has important theoretical and practical value.

  13. Depressão em trabalhadores de linhas elétricas de alta tensão Depression in high voltage power line workers

    Directory of Open Access Journals (Sweden)

    Suerda Fortaleza de Souza

    2012-06-01

    Full Text Available OBJETIVO: Investigar a associação entre desequilíbrio esforços-recompensas no trabalho e sintomas depressivos em trabalhadores de linhas elétricas de alta tensão. MÉTODOS: Estudo de corte transversal realizado em 158 trabalhadores de uma empresa de energia elétrica no Nordeste do Brasil. As dimensões do modelo esforço-recompensa (ERI constituíram as variáveis independentes principais e a variável resposta foi depressão, medida pela escala Center for Epidemiologic Studies Depression (CES-D. Os dados foram analisados com técnicas de regressão logística múltipla. RESULTADOS: Trabalhadores no grupo de baixa recompensa apresentaram prevalência de depressão 6,2 vezes maior em relação àqueles no grupo de alta recompensa. A prevalência de depressão foi 3,3 vezes maior entre os trabalhadores em condição de desequilíbrio esforço-recompensa do que entre aqueles em situação de equilíbrio. CONCLUSÕES: A prevalência de depressão estava fortemente associada às dimensões de esforços e recompensas presentes no trabalho dos eletricitários.OBJECTIVE: To investigate the association between effort-reward imbalance and depressive symptoms among workers in high voltage power lines. METHODS: A cross-sectional study among 158 workers from an electric power company in Northeast Brazil. The main independent variables were the Effort-Reward Imbalance Model (ERI dimensions and the main dependent variable was the prevalence of depression, as measured by the Center for Epidemiologic Studies Depression (CES-D scale. Data were analyzed by multiple logistic regression techniques. RESULTS: The group of low reward workers presented a depression prevalence rate 6.2 times greater than those in the high reward group. The depression prevalence rate was 3.3 greater in workers in the situation of imbalanced effort-reward than in those in effort-reward equilibrium. CONCLUSIONS: The prevalence of depression was strongly associated with psychosocial

  14. LINES

    Directory of Open Access Journals (Sweden)

    Minas Bakalchev

    2015-10-01

    Full Text Available The perception of elements in a system often creates their interdependence, interconditionality, and suppression. The lines from a basic geometrical element have become the model of a reductive world based on isolation according to certain criteria such as function, structure, and social organization. Their traces are experienced in the contemporary world as fragments or ruins of a system of domination of an assumed hierarchical unity. How can one release oneself from such dependence or determinism? How can the lines become less “systematic” and forms more autonomous, and less reductive? How is a form released from modernistic determinism on the new controversial ground? How can these elements or forms of representation become forms of action in the present complex world? In this paper, the meaning of lines through the ideas of Le Corbusier, Leonidov, Picasso, and Hitchcock is presented. Spatial research was made through a series of examples arising from the projects of the architectural studio “Residential Transformations”, which was a backbone for mapping the possibilities ranging from playfulness to exactness, as tactics of transformation in the different contexts of the contemporary world.

  15. A Reference Model for Virtual Machine Launching Overhead

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hao; Ren, Shangping; Garzoglio, Gabriele; Timm, Steven; Bernabeu, Gerard; Chadwick, Keith; Noh, Seo-Young

    2016-07-01

    Cloud bursting is one of the key research topics in the cloud computing communities. A well designed cloud bursting module enables private clouds to automatically launch virtual machines (VMs) to public clouds when more resources are needed. One of the main challenges in developing a cloud bursting module is to decide when and where to launch a VM so that all resources are most effectively and efficiently utilized and the system performance is optimized. However, based on system operational data obtained from FermiCloud, a private cloud developed by the Fermi National Accelerator Laboratory for scientific workflows, the VM launching overhead is not a constant. It varies with physical resource utilization, such as CPU and I/O device utilizations, at the time when a VM is launched. Hence, to make judicious decisions as to when and where a VM should be launched, a VM launching overhead reference model is needed. In this paper, we first develop a VM launching overhead reference model based on operational data we have obtained on FermiCloud. Second, we apply the developed reference model on FermiCloud and compare calculated VM launching overhead values based on the model with measured overhead values on FermiCloud. Our empirical results on FermiCloud indicate that the developed reference model is accurate. We believe, with the guidance of the developed reference model, efficient resource allocation algorithms can be developed for cloud bursting process to minimize the operational cost and resource waste.

  16. Overheads Reduction: Policy Change as a Political Innovation

    Directory of Open Access Journals (Sweden)

    Böcskei, Balázs

    2016-07-01

    Full Text Available The study investigates the overheads reduction initiative, leading issue of public policy in Hungary between 2013 and 2014 in the face of the punctuated equilibrium theory. The case is examined from the perspective of how the punctuated equilibrium theory and the associated concepts (as policy image, policy monopoly and stream can be applied to the overheads reduction initiative, a significant change in the public policy. After clarifying the terminology, the study presents that the increase of the expenditure of the domestic energy along with the rising number of those in arrears have already been issued as a real societal problem for years. Nevertheless, the intermittent character and the emergence of the policy image and monopoly can be justified with the priority of political aspects and the aspiration for bigger popularity. The series of provisions of the overheads reduction initiative perfectly match the governmental narrative. Between the discourse of the overheads reduction initiative generated by the government and the punctuated equilibrium provisions and the climax of popularity of Fidesz, a close interrelation can be detected. However, the widespread support of Fidesz cannot exclusively be attributed to the overheads reduction initiative.

  17. Biceps instability and Slap type II tear in overhead athletes.

    Science.gov (United States)

    Osti, Leonardo; Soldati, Francesco; Cheli, Andrea; Pari, Carlotta; Massari, Leo; Maffulli, Nicola

    2012-10-01

    Type II lesions are common lesions encountered in overhead athletes with controversies arising in term of timing for treatment, surgical approach, rehabilitation and functional results. The aim of our study was to evaluate the outcomes of arthroscopic repair of type II SLAP tears in overhead athletes, focusing on the time elapsed from diagnosis and treatment, time needed to return to sport, rate of return to sport and to previous level of performance, providing an overview concerning evidence for the effectiveness of different surgical approaches to type II SLAP tears in overhead athletes. A internet search on peer reviewed Journal from 1990, first descriprion of this pathology, to 2012, have been conducted evaluating the outcomes for both isolated Slap II tear overhead athletes and those who presented associated lesions treated. The results have been analyzed according to the scale reported focusing on return to sport and level of activity. Apart from a single study, non prospective level I and II studies were detected. Return to play at the same level ranged form 22% to 94% with different range of technique utilized with the majority of the authors recommending the fixation of these lesions but biceps tenodesis can lead to higher satisfaction racte when directly compated to the anchor fixation. Associated pathologies such as partial or full tickness rotator cuff tear did not clearly affect the outcomes and complications rate. There is no consensus regarding timing and treatment for type II SLAP, especially in overhead athletes who need to regain a high level of performance.

  18. Fault Locating in HVDC Transmission Lines Using Generalized Regression Neural Network and Random Forest Algorithm

    Directory of Open Access Journals (Sweden)

    M. Farshad

    2013-09-01

    Full Text Available This paper presents a novel method based on machine learning strategies for fault locating in high voltage direct current (HVDC transmission lines. In the proposed fault-location method, only post-fault voltage signals measured at one terminal are used for feature extraction. In this paper, due to high dimension of input feature vectors, two different estimators including the generalized regression neural network (GRNN and the random forest (RF algorithm are examined to find the relation between the features and the fault location. The results of evaluation using training and test patterns obtained by simulating various fault types in a long overhead transmission line with different fault locations, fault resistance and pre-fault current values have indicated the efficiency and the acceptable accuracy of the proposed approach.

  19. Reduced Voltage Scaling in Clock Distribution Networks

    Directory of Open Access Journals (Sweden)

    Khader Mohammad

    2009-01-01

    Full Text Available We propose a novel circuit technique to generate a reduced voltage swing (RVS signals for active power reduction on main buses and clocks. This is achieved without performance degradation, without extra power supply requirement, and with minimum area overhead. The technique stops the discharge path on the net that is swinging low at a certain voltage value. It reduces active power on the target net by as much as 33% compared to traditional full swing signaling. The logic 0 voltage value is programmable through control bits. If desired, the reduced-swing mode can also be disabled. The approach assumes that the logic 0 voltage value is always less than the threshold voltage of the nMOS receivers, which eliminate the need of the low to high voltage translation. The reduced noise margin and the increased leakage on the receiver transistors using this approach have been addressed through the selective usage of multithreshold voltage (MTV devices and the programmability of the low voltage value.

  20. Toward the Optimal Configuration of Dynamic Voltage Scaling Points in Real-Time Applications

    Institute of Scientific and Technical Information of China (English)

    Hui-Zhan Yi; Xue-Jun Yang

    2006-01-01

    In real-time applications, compiler-directed dynamic voltage scaling (DVS) could reduce energy consumption efficiently, where compiler put voltage scaling points in the proper places, and the supply voltage and clock frequency were adjusted to the relationship between the reduced time and the reduced workload. This paper presents the optimal configuration of dynamic voltage scaling points without voltage scaling overhead, which minimizes energy consumption. The conclusion is proved theoretically. Finally, it is confirmed by simulations with equally-spaced voltage scaling configuration.

  1. Evaluation of Communication Overheads in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Shiv Prasad Kori1 , Dr. R. K . Baghel2

    2013-04-01

    Full Text Available Wireless sensor network are collection of small sensing self powered nodes organized into a cooperative network which have certain processing capabilities and the nodes communicate wirelessly. Sensing, processing and communication are three key elements whose combination in one node gives rise to a vast number of applications of wireless sensor networks in areas such as environmental monitoring, warfare, education, agriculture to name a few. In the present work, the comparative evaluation of communication overhead due to sink mobility with speed variations, the effect of update time variation, the effect of number of nodes used in the wirelesssensor networks is carried out. It has been observed that communication overheads increasesignificantly when sink mobility is high. The communication overheads can be reduced by increasing update time

  2. Modeling Routing Overhead Generated by Wireless Proactive Routing Protocols

    CERN Document Server

    Javaid, Nadeem; Javaid, Akmal; Malik, Shahzad A

    2011-01-01

    In this paper, we present a detailed framework consisting of modeling of routing overhead generated by three widely used proactive routing protocols; Destination-Sequenced Distance Vector (DSDV), Fish-eye State Routing (FSR) and Optimized Link State Routing (OLSR). The questions like, how these protocols differ from each other on the basis of implementing different routing strategies, how neighbor estimation errors affect broadcast of route requests, how reduction of broadcast overhead achieves bandwidth, how to cope with the problem of mobility and density, etc, are attempted to respond. In all of the above mentioned situations, routing overhead and delay generated by the chosen protocols can exactly be calculated from our modeled equations. Finally, we analyze the performance of selected routing protocols using our proposed framework in NS-2 by considering different performance parameters; Route REQuest (RREQ) packet generation, End-to-End Delay (E2ED) and Normalized Routing Load (NRL) with respect to varyi...

  3. Accounting of allocation of production enterprises’ overhead costs

    Directory of Open Access Journals (Sweden)

    О.V. Ivaniuta

    2016-12-01

    Full Text Available Taking into account the complexity of engineering technological cycles, the use of traditional approaches to the allocation of overhead costs at the researching enterprises is inexpedient and inefficient. The authors find out that to solve this problem it is not enough to choose only one base of allocation because the formed prime cost with such an approach will not meet the reality. That is why it is suggested to use a multilevel allocation of overhead costs. The proposed approach involves the allocation of overhead costs at the following levels: fixed and variable, with shops of main and auxiliary production, calculation stations, some orders. Each level involves the selection of individual allocation bases that are grouped on economic, technological and integrated ones.

  4. On the Overhead of Interference Alignment: Training, Feedback, and Cooperation

    CERN Document Server

    Ayach, Omar El; Heath, Robert W

    2012-01-01

    Interference alignment (IA) is a cooperative transmission strategy that, under some conditions, achieves the interference channel's maximum number of degrees of freedom. Realizing IA gains, however, is contingent upon providing transmitters with sufficiently accurate channel knowledge. In this paper we study the performance of IA in multiple-input multiple-output systems where channel knowledge is acquired through training and analog feedback. We design the training and feedback system to maximize IA's effective sum-rate: a non-asymptotic performance metric that accounts for estimation error, training and feedback overhead, and channel selectivity. We characterize effective sum-rate with overhead in relation to various parameters such as signal-to-noise ratio, Doppler spread, and feedback channel quality. We show that the overhead of IA can be optimized to ensure good performance in a wide range of fading scenarios. Finally, we show how this analysis can help solve network design problems such as finding the ...

  5. Research on Neutral Point Drifting Technology Based on the Same Harmonic Distribution of Line Voltage%基于相同线电压谐波频带的中性点漂移技术仿真研究

    Institute of Scientific and Technical Information of China (English)

    徐振; 罗仁俊; 黄欢; 钟强; 陈志新

    2011-01-01

    提出了一种基于相同线电压谐波频带的中性点漂移技术。该方法通过对载波相移角度和频率调制比等参数的优化,实现了3个线电压的高次谐波频带保持一致。与常规的故障功率单元处理方法相比,该方法能增加输出线电压的幅值,同时能减少其总谐波含量(Total Harmonic Distortion,THD)。通过仿真验证了该方法的有效性。%Neutral point drifting technology based on the same harmonic distribution of line voltage is proposed.With the optimization of carrier phase-shifted angle and frequency modulation ratio,the harmonic distribution of three line voltages can be consistent.Comparing with the normal failure power unit treatment,the amplitude of output voltage can be increased and THD(Total Harmonic Distortion) can be decreased.Simulation results verify the validity of the proposed method.

  6. Experimental Study of Bad Contact of Low-Voltage Line Based on Needle-Plate Model%基于针-板模型低压电气线路接触不良的试验研究

    Institute of Scientific and Technical Information of China (English)

    胡帅; 王成江; 李如锋; 李光

    2012-01-01

      This paper made a needle-plate model to make clear of discharge position and to identify discharge characteristics of low-voltage line when discharge appeared on line load due to bad contact. By changing the position of the needle-plate model in the circuit, the digital oscil-loscope was adopted to collect the voltage waveforms of null line when model was in different position. The experiment study shows that there are different discharge characteristics of null line voltage waveforms when the model is in different position, which has definite regularity.%  为解决低压电气线路因出现接触不良而发生放电,及其放电源位置的确定和放电特征识别等问题,制作了针-板模型来模拟导体间接触不良。通过改变针-板模型位于线路中的位置,利用数字示波器采集模型处于线路不同位置时零线上的电压波形。试验表明:模型处于线路不同位置发生放电现象,其对应的零线电压波形具有不同的放电特征且具有一定的规律性。

  7. 低压电力线载波通信与抗干扰解决途径%Solutions for low-voltage power line carrier communication and anti-jamming

    Institute of Scientific and Technical Information of China (English)

    赵新正; 姚发久; 白崇乾; 王阳

    2014-01-01

    Since the power grid is the largest,most popular and reliable network,data transmission through low-voltage power line is the most economical way to use the existing resource. The technology for low-voltage power line multi-frequency self-adaption DSSS carrier communication was created by Shaanxi Kaistar Company,in which the development of IC chip and thick film circuit were included. The jamming from low-voltage power line was completely solved on the basis of the data concentrator, data acquisition unit,data controller and anti-jamming products. The application of power line carrier communication in the energy resources measurement and monitoring platform is superior to the other technologies.%电网是最大、最普及、最可靠的供电网,利用低压电力线实现数据传输,具有利用现有资源、减少投资的现实意义。陕西凯星公司独创了低压电力线多频段自适应直接序列展频载波通信技术,从IC芯片、厚膜电路的研发,从电力线载波数据集中器、采集器、控制器及抗干扰硬件产品入手,彻底解决了低压电力线上的干扰问题。该技术应用在能源计量监控平台方面,是其他技术无法比拟的。

  8. Design and application of on-line monitoring system for capacitor voltage transformer%电容式电压互感器绝缘在线监测系统设计与应用

    Institute of Scientific and Technical Information of China (English)

    黄嘉鹏; 陈贤顺; 张福州; 李涛

    2016-01-01

    In order to ensure capacitor voltage transformer(CVT) in safe operation, an on-line monitoring system has been designed. In this paper, on on-line monitoring program is given and equivalent circuit of CVT is established. Calc-ulation formula of dielectric loss factor and capacity for CVT are deduced. Design of on-line monitoring system for ins-ulating property is in detail introduced, including current signal acquisition circuit, voltage signal acquisition circuit and A/D sampling circuit. The on-line monitoring system has been applicated to 500kV substation in Sichuan. The accuracy and effectiveness of the online monitoring system monitoring are verified by monitoring results.%为保障电容式电压互感器(Capacitor Voltage Transformer, CVT)的安全可靠运行,设计了绝缘在线监测系统。给出了CVT在线监测方案,建立了CVT等值电路,推导了介质损耗角正切值和电容量的计算公式,详细阐述了绝缘在线监测系统的设计,包括:电流信号采集电路、电压信号采集电路和A/D采样电路等。该监测系统已经在四川某500kV变电站进行了挂网运行,在线监测结果验证了在线监测系统监测的准确性和有效性。

  9. Interferences and Solutions in Power Line Carrier Communication with Low Voltage%浅谈低压电力线载波通信中的干扰及解决措施

    Institute of Scientific and Technical Information of China (English)

    胡瑞

    2015-01-01

    The power line carrier communication (PLC) is a kind of communication method that transmits the data signal and audio signal through the power line. This papers introduces the solutions to reduce or overcome the interferences based on analyzing the noises and interferences in power line carrier communication with low voltage.%电力线载波通信技术是采用电力线传送数据和话音信号的一种通信方式。本文通过分析低压电力线载波通信中存在的噪声和干扰情况,介绍了减少或克服这些干扰的解决方法。

  10. 考虑线路多种停运模式的静态电压稳定风险评估%Risk Assessment of Static Voltage Stability by Considering Multiple Outage Model of Lines

    Institute of Scientific and Technical Information of China (English)

    吴昊; 薛贵挺; 张焰; 杨增辉; 冯煜尧

    2011-01-01

    Due to the common mode outages and dependent outages have great impact on system static voltage stability,this paper focuses on the establishment of the equivalent branch outage model for two parallel transmission lines by considering outage overlapping, then computes the state probability of transmission system. Basing on the state probability model of power system, a risk index system of static voltage stability and the calculation method of every index are presented. By the voltage stability criteria based on CPF and optimal load shedding model, the loss of voltage stability of transmission system can be judged and controlled. Taking an area of power grid for east china for example, the risk of static voltage stability is assessed, which verifies the effectiveness of the proposed method.%鉴于双回平行输电线路共同模式停运和相关停运对系统电压稳定性影响较大,本文重点建立了双回线多种停运模式重叠的支路等效停运模型,进而计算输电系统状态概率.在输电系统状态概率模型的基础上,提出输电系统静态电压稳定风险评估指标体系及各项指标计算方法,其中通过基于连续潮流的电压稳定性判据及最优切负荷模型,对输电系统电压失稳进行判定及校正控制.最后以华东某地区电网为例进行静态电压稳定风险评估,说明本文所提方法的有效性.

  11. 低压电力线通讯网络技术发展的研究%Research on the development of low voltage power line communication network technology

    Institute of Scientific and Technical Information of China (English)

    李非文

    2013-01-01

    Carrier communication over high voltage power line has been developing for near one hundred years .It has many applications for voice communication in power distribution,data collection from tele-control instrumentation,and so on.However,using power line within one transformer area to provide Internet access is a just recent development.Power Line Communications Networks(here after,“PLC Networks”)addressed in this dissertation include technologies that use the low voltage power lines to carry data transmissions or establish a computer network.PLC Networks,due to the ubiquitous nature of Power lines,present a solution to providing wide reaching Internet access,which have important technological and economic implications.%  高压电力线载波通信已有近百年的历史,它在电力调度话音通信、电力系统远动装置数据采集等方面取得了卓有成效的应用,但是利用一个台区的低压电力线建立Internet接入网是近几年来国际上刚刚兴起的技术。本文论述的电力线通信(Power Line Communications)计算机网络(以下简称PLC网络)是以电力线为通信介质实现数据传输或建立计算机网络的相关技术研究。由于低压电力线的普及程度比其他任何通信介质都广泛,研究电力线作为信息传输介质在技术和经济方面都有十分重要的意义。

  12. 30 CFR 77.1503 - Augering equipment; overhead protection.

    Science.gov (United States)

    2010-07-01

    ... UNDERGROUND COAL MINES Auger Mining § 77.1503 Augering equipment; overhead protection. (a) Auger machines which are exposed to highwall hazards, together with all those parts of any coal elevating conveyors... connecting or disconnecting auger sections under a highwall, at least one person shall be assigned to...

  13. Dissolving Carboxylic Acids and Primary Amines on the Overhead Projector

    Science.gov (United States)

    Solomon, Sally D.; Rutkowsky, Susan A.

    2010-01-01

    Liquid carboxylic acids (or primary amines) with limited solubility in water are dissolved by addition of aqueous sodium hydroxide (or hydrochloric acid) on the stage of an overhead projector using simple glassware and very small quantities of chemicals. This effective and colorful demonstration can be used to accompany discussions of the…

  14. Overhead Projector Demonstrations: Some Ideas from the Past.

    Science.gov (United States)

    Kolb, Doris

    1987-01-01

    Describes nine chemistry demonstrations that can be done using an overhead projector. Includes demonstrations on common ion effect, crystal formation from supersaturated solutions, making iron positive with nitric acid, optical activity, carbon dioxide in human breath, amphoteric hydroxides, the surface tension of mercury, and natural acid-base…

  15. Phase Sensitive Cueing for 3D Objects in Overhead Images

    Energy Technology Data Exchange (ETDEWEB)

    Paglieroni, D

    2005-02-04

    Locating specific 3D objects in overhead images is an important problem in many remote sensing applications. 3D objects may contain either one connected component or multiple disconnected components. Solutions must accommodate images acquired with diverse sensors at various times of the day, in various seasons of the year, or under various weather conditions. Moreover, the physical manifestation of a 3D object with fixed physical dimensions in an overhead image is highly dependent on object physical dimensions, object position/orientation, image spatial resolution, and imaging geometry (e.g., obliqueness). This paper describes a two-stage computer-assisted approach for locating 3D objects in overhead images. In the matching stage, the computer matches models of 3D objects to overhead images. The strongest degree of match over all object orientations is computed at each pixel. Unambiguous local maxima in the degree of match as a function of pixel location are then found. In the cueing stage, the computer sorts image thumbnails in descending order of figure-of-merit and presents them to human analysts for visual inspection and interpretation. The figure-of-merit associated with an image thumbnail is computed from the degrees of match to a 3D object model associated with unambiguous local maxima that lie within the thumbnail. This form of computer assistance is invaluable when most of the relevant thumbnails are highly ranked, and the amount of inspection time needed is much less for the highly ranked thumbnails than for images as a whole.

  16. Multimodal Neural Network for Overhead Person Re-identification

    DEFF Research Database (Denmark)

    Lejbølle, Aske Rasch; Nasrollahi, Kamal; Krogh, Benjamin

    2017-01-01

    similar persons. Because of challenges regarding changes in lighting between views, occlusion or even privacy issues, more focus has turned to overhead and depth based camera solutions. Therefore, we have developed a system, based on a Convolutional Neural Network (CNN) which is trained using both depth...

  17. Conversion of Bench Demonstration Using the Overhead Projector.

    Science.gov (United States)

    Johnstone, A. H.; Al-Shuaili, Ali

    2001-01-01

    Presents a new technique for projecting science demonstrations, enabling a larger number of students to see the demonstration without scaling up the experiment. Describes innovative attachments that magnify projector images using mirrors, solutions to the problem of convergent test tubes, development of overhead projection experiments, necessary…

  18. 基于电力载波通信的LED隧道照明控制器设计%Design of LED tunnel illumination controller based on low voltage power line communication

    Institute of Scientific and Technical Information of China (English)

    汪义旺; 张波; 吴铄

    2011-01-01

    设计了一种基于低压电力载波通信技术的智能LED隧道照明控制器,用于LED隧道照明的自动化远程控制.控制器主要由LED恒流驱动电路、主控单元和电力载波通信等部分组成,利用低压电力载波通信技术,可以方便的实现LED隧道照明的组网控制.实验与工程应用结果均表明该控制器控制效果好、工作稳定、成本低且易于实现,具有很好的应用前景.%An intelligent LED tunnel illumination controller based on low voltage power line communication technology was designed, used in the LED tunnel illumination remote automation control system. The controller mainly included LED constant current driver circuit, control unit and power line communications components, and adopted the low-voltage power line communication technology to achieve LED tunnel illumination network control. The experiment and project application results show that the controller has good performance, control stable, low cost and was easy to implement. At last, the controller has great development prospect.

  19. 基于GSM/GIS的高压输电线路故障计算机监测系统%High-Voltage Transmission Line Fault Computer Inspection System Based on GSM/GIS

    Institute of Scientific and Technical Information of China (English)

    陈森法; 陈智军; 赵敏; 卢旭

    2011-01-01

    Due to wide distribution and great number of branches of high-voltage transmission line, it consumes much time and energy to find fault. According to the advantage of GSM and G1S, a high-voltage transmission line management system having GSM network as the fault transmission manner and GIS as the computer system platform is proposed . The system's overall frame is given,and the hardware and software design for the system is also given . The fault data is sent to the control center with short messages,and the backend GIS system of the control system shows directly the fault node on the map and sends short messages to maintenance personnel' s mobile. It is demonstrated in the experiment that the system can reduce obviously the maintenance time for high-voltage transmission line fault.%高压输电线路传输分布广、分支多,依靠人工方式查找故障费时费力.结合GSM和GIS的各自优点,提出以GSM网络作为故障数据传输方式和以GIS作为计算机系统平台的高压输电线路管理系统;给出了系统的整体框架,并介绍了该系统的软硬件设计.通过短消息方式,该系统将监测节点检测到的故障数据发回监控中心,监控中心的后台GIS在地图上将故障节点直观地显示出来,并发送短消息到维修人员手机上.实验结果表面,该系统能明显地降低高压输电线路故障的维修时间.

  20. 一起电容式电压互感器绝缘在线监测案例分析%Analysis of an On-line Monitoring Insulation Case of Capacitor Voltage Transformer

    Institute of Scientific and Technical Information of China (English)

    陈敏维; 李棣; 季征南; 张孔林; 江修波; 张少涵

    2012-01-01

    电容式电压互感器(CVT)是变电站的重要设备,测量其介质损耗因素和电容量可以及时发现设备的绝缘缺陷.但是由于其特殊的绝缘结构,使得诊断变得更加复杂.针对这个问题,笔者通过一起CVT的案例,基于测量的原理和基本结构,分析了电容单元在出现故障时,介质损耗因素和电容量的在线监测数据明显变化,而离线测量介质损耗因素的数据基本不变.对电容量明显变化的原因,提出了相应的预防事故措施.同时,验证了在线监测CVT数据的可靠性和有效性.%Capacitor voltage transformer is major substation equipment. Measuring their dielectric loss angle and capacitance can help one timely detect insulation defects in the equipment. However, its special insulation structure makes the diagnosis more complicated. In this paper, a fault case of capacitor voltage transformer is analyzed based on the principle of measurement and the structure of measuring device, and the result indicates that the on-line monitoring data of dielectric loss factor and capacitance change obviously when a fault happens in capacitor, while the off-line detecting data of dielectric loss factor keeps stable but capacitance changes clearly. The reliability and effectiveness of the on-line monitoring method for capacitor voltage transformer is verified. Some countermeasures against the cause corresponding to the clear variation of capacitance are suggested.

  1. Impact dynamics model of long span high voltage transmission lines subjected to iced wire breakage%大跨越高压输电线路覆冰断线的冲击动力学模型

    Institute of Scientific and Technical Information of China (English)

    刘春城; 初佂宇; 孙显鹤; 张伟

    2012-01-01

    In order to theoretically reveal the impact dynamic responses of long span high voltage transmission lines subjected to iced wire breakage, the impact dynamics model for long span high-voltage transmission lines with iced bundled conductors was developed comprehensively by using an equivalent single iced conductor instead of bundled conductors. The impact dynamics model of iced wire breakage was derived by using energy method. Taking a typical tension section of long span high-voltage transmission line as an example, the impact responses under iced wire breakage and non-iced wire breakage were computed by using this model and a good agreements were achieved. The results show that the impact dynamic response under iced wire breakage is larger than that under non-iced wire breakage, so the impact dynamic response due to iced wire breakage should not be ignored. The model can provide a theoretical basis for experiments and numerical simulations of long span high voltage transmission lines under iced wire breakage.%为了从理论上揭示大跨越高压输电线路覆冰断线的冲击动力响应,针对大跨越高压输电导线分裂布置型式的线路覆冰情况,采用等效单根导线代替分裂导线,利用能量法,建立了覆冰断线的冲击动力学模型.以某大跨越高压输电线路的一个典型耐张段为例,应用该模型计算导(地)线覆冰断线和未覆冰断线工况下对铁塔造成的冲击响应.研究表明:覆冰断线造成的冲击动力响应远大于未覆冰断线情况,覆冰断线冲击响应不容忽视.该模型可为大跨越高压输电线路覆冰断线的冲击动力响应试验分析与数值计算提供理论依据.

  2. Simulation Study of Induced Voltage and Current of Power Transmission Line in Double Circuits on the Same Tower%同塔双回输电线路中感应电压和电流仿真研究

    Institute of Scientific and Technical Information of China (English)

    孔晨华; 杨建军; 山磊; 孔令新; 李正鹏

    2015-01-01

    同塔电路回线中,当发生一回线停电检修且另一回线路正常运行时,基于其所在输电线路间电磁感应及静电感应的作用,势必会出现检修时的感应电压和电流的现象,会对低压线路上的维修人员造成威胁,针对此,文章将以同塔双回的500 kV高压输电线路为例,并结合对EMTP仿真软件的利用,分析了不正常运行情况下的感应电压、电流,验证了仿真计算结果的有效性。%In line with circuit towers, when a time line outage maintenance and normal operation of different lines, based on its transmission line electromagnetic induction and the effect of electrostatic induction, will appear the phenomenon of induction voltage and current, maintenance will pose a threat to the low-tension wire road maintenance personnel, for this. Taking the 500 kV transmission lines with double towers as an example, combined with the use of EMTP simulation software, the abnormal operation of induction voltage, current were analyzed, the validity of the simulation calculation results was veriifed.

  3. Balancing the Lifetime and Storage Overhead on Error Correction for Phase Change Memory.

    Science.gov (United States)

    An, Ning; Wang, Rui; Gao, Yuan; Yang, Hailong; Qian, Depei

    2015-01-01

    As DRAM is facing the scaling difficulty in terms of energy cost and reliability, some nonvolatile storage materials were proposed to be the substitute or supplement of main memory. Phase Change Memory (PCM) is one of the most promising nonvolatile memory that could be put into use in the near future. However, before becoming a qualified main memory technology, PCM should be designed reliably so that it can ensure the computer system's stable running even when errors occur. The typical wear-out errors in PCM have been well studied, but the transient errors, that caused by high-energy particles striking on the complementary metal-oxide semiconductor (CMOS) circuit of PCM chips or by resistance drifting in multi-level cell PCM, have attracted little focus. In this paper, we propose an innovative mechanism, Local-ECC-Global-ECPs (LEGE), which addresses both soft errors and hard errors (wear-out errors) in PCM memory systems. Our idea is to deploy a local error correction code (ECC) section to every data line, which can detect and correct one-bit errors immediately, and a global error correction pointers (ECPs) buffer for the whole memory chip, which can be reloaded to correct more hard error bits. The local ECC is used to detect and correct the unknown one-bit errors, and the global ECPs buffer is used to store the corrected value of hard errors. In comparison to ECP-6, our method provides almost identical lifetimes, but reduces approximately 50% storage overhead. Moreover, our structure reduces approximately 3.55% access latency overhead by increasing 1.61% storage overhead compared to PAYG, a hard error only solution.

  4. Generator of ultrashort megavolt voltage pulses

    CERN Document Server

    Zheltov, K A; Shalimanov, V F

    2002-01-01

    Paper describes approx 3 ns duration and > 1 MW amplitude voltage pulse generator under high-ohmic (approx 450 Ohm) load. Generator comprises pulse transformer with magnetized core, as well as, resonance tuned circuit of high-voltage solenoid and accumulating spaces of a shaping line containing, moreover, spark gap to switch charge in transmitting line. Paper contains the results of voltage measuring in generator basic units

  5. Sizing of SRAM Cell with Voltage Biasing Techniques for Reliability Enhancement of Memory and PUF Functions

    Directory of Open Access Journals (Sweden)

    Chip-Hong Chang

    2016-08-01

    Full Text Available Static Random Access Memory (SRAM has recently been developed into a physical unclonable function (PUF for generating chip-unique signatures for hardware cryptography. The most compelling issue in designing a good SRAM-based PUF (SPUF is that while maximizing the mismatches between the transistors in the cross-coupled inverters improves the quality of the SPUF, this ironically also gives rise to increased memory read/write failures. For this reason, the memory cells of existing SPUFs cannot be reused as storage elements, which increases the overheads of cryptographic system where long signatures and high-density storage are both required. This paper presents a novel design methodology for dual-mode SRAM cell optimization. The design conflicts are resolved by using word-line voltage modulation, dynamic voltage scaling, negative bit-line and adaptive body bias techniques to compensate for reliability degradation due to transistor downsizing. The augmented circuit-level techniques expand the design space to achieve a good solution to fulfill several otherwise contradicting key design qualities for both modes of operation, as evinced by our statistical analysis and simulation results based on complementary metal–oxide–semiconductor (CMOS 45 nm bulk Predictive Technology Model.

  6. Protection Principle for HVDC Transmission Lines Based on Fault Component of Voltage and Current%基于电压和电流突变量的高压直流输电线路保护原理

    Institute of Scientific and Technical Information of China (English)

    邢鲁华; 陈青; 付兆远; 高湛军; 于春光

    2012-01-01

    A new main protection principle is presented for high voltage direct current(HVDC) transmission lines.The principle is based on the variation characteristics of fault component of voltage and current,together with an indepth research on the transients caused by internal faults,external faults and lightning disturbances.By a set threshold for the ratio of amplitudes of the fault components of voltage at the same side relay location on bipolar lines,faults outside HVDC lines can be excluded,and the fault line can be distinguished.The polarities of the fault component of currents at the ends of the fault line are different for internal faults,while are the same for external faults.Accordingly,internal faults and external faults can be distinguished.Simulation results based on PSCAD/EMTDC for a practical HVDC transmission system demonstrate that the fault line can be rapidly selected and internal faults and external faults can be distinguished by the protection under bipolar neutral grounding at both ends mode.Lightning disturbances can be excluded by the proposed criterion.The protection criterion can move accurately for faults with high transition resistance and lightning induced faults,and can be also applied under one pole with 70% voltage and one pole with total voltage operation mode,anti-way power delivery operation mode,monopolar metallic return operation mode and one pole with maintenance outage.The calculation requirement of the protection criterion can be satisfied with sampling frequency in the range of 10~100 kHz.%在对高压直流输电线路区内、外故障和雷击等暂态过程研究的基础上,提出了一种基于电压、电流突变量变化特征的高压直流输电线路主保护原理。该原理对两极线路同侧保护安装处测得的电压突变量幅值的比值设定阈值,选出故障极;利用故障线路两端电流突变量的极性在线路保护区内故障时相异、在区外故障时相同,区分线路上保护区

  7. 76 FR 26949 - Special Conditions: Boeing Model 747-8 Series Airplanes; Overhead Flight Attendant Rest Compartment

    Science.gov (United States)

    2011-05-10

    ...; Overhead Flight Attendant Rest Compartment AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... installation of an overhead flight attendant rest compartment. The applicable airworthiness regulations do not... installing an overhead flight attendant rest (OFAR) compartment creates a smaller compartment volume...

  8. Analysis and modeling of low voltage electrical network at power line carrier frequencies (3-148.5 kHz); Analyse et modelisation du reseau basse tension aux frequences courants porteurs (3 KHZ-148,5 KHZ)

    Energy Technology Data Exchange (ETDEWEB)

    Duval, G.

    1998-07-01

    Electricite de France (EdF) wishes to establish a physical communication link between his clients and the EdF centres. The final link, i.e. between the high/low voltage transformation substation and the residential clients, being ensured by carrier currents. With this aim, an analysis and a modeling of the low voltage network at the carrier frequencies (3 kHz - 148.5 kHz) has been performed. This work has been carried out in parallel with an experiment involving 3500 apparatuses that use carrier currents. The diversity of the French low voltage networks and the limitations imposed by the EN50065-1 standard about the use of carrier currents in Europe do not favour the development of such carrier current systems. Disturbing voltages and localized impedances represent the main difficulties to get round. Inside accommodations, domotic carrier currents have a reduced range but a higher disturbance amplitude because of the proximity of appliances. A differential mode to common mode conversion phenomenon has been evidenced which generates network couplings and important electromagnetic fields. Energy lines and cables have been analyzed using numerical models. Load peaks have been analyzed using statistical tools in order to take into account the daily fluctuations. The modeling of the network is made in two steps: a double-wire model is considered first. Then a three-phase model is developed which analyzes the inter-phases coupling and the effect of the distribution of clients' loads on each phase. The results of this model are conformable with measurements except for underground networks. As perspectives of future works and beyond todays standard framework, the techniques that allow a sensible increase of communication flow rates have been reviewed. (J.S.)

  9. 基于低压电力线的高速载波模块设计%Design of high-speed PLC module based on low voltage power line

    Institute of Scientific and Technical Information of China (English)

    林佳森; 李智; 李乔峰; 马一森

    2012-01-01

    Effective choice of the solution is essential to achieve a real-time, bi-directional(full-duplex) communication of the smart grid. The Power Line Carrier(PLC) technology provides a low-cost solution, which suits China's own national conditions. In this paper, the advantages of OFDM PLC modulation technology are introduced. A PLC module of system model is established through the analysis of the input impedance under the low-voltage power line channel. The high-speed PLC module based on low-voltage Power Line is also designed according to the studies of power line channel. The results show that the design of the PLC module has featured high receiving sensitivity and anti-noise ability.%选择有效的方案实现智能电网中的双向实时通信至关重要,电力线载波(PLC)技术提供了一种适合中国国情的低成本解决方案.介绍了OFDM PLC调制技术的优势,通过分析低压电力线通信信道输入阻抗,建立了低压电力线载波模块系统模型.并在关于电力线信道的研究基础上,设计了基于低压电力线的高速载波模块.测试结果表明,该载波模块设计方案具有较高的接收灵敏度和抗噪声能力.

  10. The Teacher and Overhead Projection. A Treasury of Ideas, Uses and Techniques.

    Science.gov (United States)

    Schultz, Morton J.

    Overhead projection of visual material offers a simple and flexible tool for the classroom teacher. This book introduces the subject of overhead projection with a description of its use and capabilities. It presents sections outlining the best tools and techniques for handling overhead projection in teaching science, reading, mathematics, language…

  11. 30 CFR 56.16015 - Work or travel on overhead crane bridges.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work or travel on overhead crane bridges. 56... Materials Storage and Handling § 56.16015 Work or travel on overhead crane bridges. No person shall work from or travel on the bridge of an overhead crane unless the bridge is provided with...

  12. 30 CFR 57.16015 - Work or travel on overhead crane bridges.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work or travel on overhead crane bridges. 57... MINES Materials Storage and Handling § 57.16015 Work or travel on overhead crane bridges. No person shall work from or travel on the bridge of an overhead crane unless the bridge is provided...

  13. 低压电力线通信信道的多径效应分析%Analysis on multipath effect of communication channel in low-voltage power line

    Institute of Scientific and Technical Information of China (English)

    王智博

    2014-01-01

    Aiming at multipath fading effect of low-voltage power line communication channel, based on analysis the noise,fading and multipath characteristic of low-voltage power line commu-nication channel,puts forward the solution of using diversity technology reduce the error rate of the communication system,and using a matrix laboratory verifies its model by simulation method. The simulation result shows that using diversity technology the power communication system with mini-mum shift-frequency keying modulation can resist multipath effect.%针对低压电力线信道的多径衰减效应,在分析低压电力线信道噪声、衰减和多径特性的基础上,提出采用分集技术降低通信系统误码率的解决方案,并使用矩阵实验对其模型进行仿真验证。仿真结果表明:最小频移键控的电力通信系统采用分集技术可抵抗多径效应。

  14. Composite Extension Finite Fields for Low Overhead Network Coding

    DEFF Research Database (Denmark)

    Heide, Janus; Roetter, Daniel Enrique Lucani

    2015-01-01

    packet. This work advocates the use of multiple composite extension finite fields to address these challenges. The key of our approach is to design a series of finite fields where increasingly larger fields are based on a previous smaller field. For example, the design of a field with 256 elements F2222...... is based on polynomial arithmetic over a field with 16 elements F222, in turn based on a field with 4 elements F22. We propose a technique to modify standard Random Linear Network Coding (RLNC) to utilize a set of these fields instead of a single field and analyze the performance. The results show...... that total overhead is reduced due to reduced size of the coding vector, while maintaining low linear dependency between coded packets. The overhead can in some cases be reduced to less than one-fifth compared to standard RLNC and importantly the ability to recode is preserved....

  15. CLOMP: Accurately Characterizing OpenMP Application Overheads

    Energy Technology Data Exchange (ETDEWEB)

    Bronevetsky, G; Gyllenhaal, J; de Supinski, B

    2008-02-11

    Despite its ease of use, OpenMP has failed to gain widespread use on large scale systems, largely due to its failure to deliver sufficient performance. Our experience indicates that the cost of initiating OpenMP regions is simply too high for the desired OpenMP usage scenario of many applications. In this paper, we introduce CLOMP, a new benchmark to characterize this aspect of OpenMP implementations accurately. CLOMP complements the existing EPCC benchmark suite to provide simple, easy to understand measurements of OpenMP overheads in the context of application usage scenarios. Our results for several OpenMP implementations demonstrate that CLOMP identifies the amount of work required to compensate for the overheads observed with EPCC. Further, we show that CLOMP also captures limitations for OpenMP parallelization on NUMA systems.

  16. Vertical Jump Biomechanics Altered With Virtual Overhead Goal.

    Science.gov (United States)

    Ford, Kevin R; Nguyen, Anh-Dung; Hegedus, Eric J; Taylor, Jeffrey B

    2017-04-01

    Virtual environments with real-time feedback can simulate extrinsic goals that mimic real life conditions. The purpose was to compare jump performance and biomechanics with a physical overhead goal (POG) and with a virtual overhead goal (VOG). Fourteen female subjects participated (age: 18.8 ± 1.1 years, height: 163.2 ± 8.1 cm, weight 63.0 ± 7.9 kg). Sagittal plane trunk, hip, and knee biomechanics were calculated during the landing and take-off phases of drop vertical jump with different goal conditions. Repeated-measures ANOVAs determined differences between goal conditions. Vertical jump height displacement was not different during VOG compared with POG. Greater hip extensor moment (P biomechanical testing, screening, and training conditions.

  17. Field evaluation of a modified intervention for overhead drilling.

    Science.gov (United States)

    Rempel, David; Star, Demetra; Barr, Alan; Blanco, Marco Mendoza; Janowitz, Ira

    2010-04-01

    Drilling holes into concrete or metal ceilings is one of the most physically demanding tasks performed in construction. The work is done overhead with rotary impact hammer drills that weigh up to 40 N. The task is associated with pain and musculoskeletal disorders at the wrist, forearm, shoulder, and back. The mechanism of injury is thought to be the high forces and non-neutral shoulder and wrist postures applied during drilling. Previously, we described a field study of a foot lever and inverted drill press intervention devices that received poor usability ratings compared with the usual method for overhead drilling based on problems with mobility and productivity. Using a participatory intervention model, feedback from construction workers (N = 13) was used to develop a new intervention design that incorporated a wheeled tripod base and a unique method of aligning the drilling column to vertical. A different group of construction workers (N = 23) evaluated usability and fatigue of the new device during their regular overhead drilling in comparison with the usual method. Four of 12 usability ratings were significantly better with the intervention device compared with the usual method. Subjective shoulder fatigue was less with the new intervention (1.1 vs. 3.3; scale 0 to 5; p drilling were 26 N with the intervention compared with 245 N with the usual method. The percentage of time with the shoulder flexed or abducted to more than 60 degrees was less with the intervention compared with the usual method (21 vs. 40%; p = 0.007). There was significantly less head extension with the intervention compared with the usual method. There were no significant differences in overall productivity between the two methods. This study demonstrates that a new intervention device for overhead drilling has improved usability and subjective fatigue ratings compared with the usual method. These improvements are most likely due to the reduced hand forces, reduced shoulder abduction and

  18. Overhead-Performance Tradeoffs in Distributed Wireless Networks

    Science.gov (United States)

    2015-06-26

    AFRL-AFOSR-VA-TR-2015-0264 Overhead-Performance Tradeoffs in Distributed Wireless Networks Leonard Cimini UNIVERSITY OF DELAWARE Final Report 07/08...NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University of Delaware 210 Hullihen Hall Newark, DE 19716 8...NUMBER (Include area code) 302-831-4943 Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std . Z39.18 Adobe Professional 7.0 Reset DISTRIBUTION A

  19. Contract Overhead Reduction Across the Department of Defense

    Science.gov (United States)

    2016-02-16

    contracts also indicate that, in general, the predominant types of contracts are fixed price contracts, with cost plus remaining only a small...strategy, a business adds a portion or representative share of overhead costs to the sales price of items or overall price of services in order to...exceeding specified standards or goals.”5 There are two broad category types of contracts – fixed price and cost reimbursement contracts. In the first

  20. SHOULDER MUSCLE IMBALANCE AND SUBACROMIAL IMPINGEMENT SYNDROME IN OVERHEAD ATHLETES

    OpenAIRE

    Page, Phil

    2011-01-01

    Subacromial impingement is a frequent and painful condition among athletes, particularly those involved in overhead sports such as baseball and swimming. There are generally two types of subacromial impingement: structural and functional. While structural impingement is caused by a physical loss of area in the subacromial space due to bony growth or inflammation, functional impingement is a relative loss of subacromial space secondary to altered scapulohumeral mechanics resulting from glenohu...

  1. Modeling the Virtual Machine Launching Overhead under Fermicloud

    Energy Technology Data Exchange (ETDEWEB)

    Garzoglio, Gabriele [Fermilab; Wu, Hao [Fermilab; Ren, Shangping [IIT, Chicago; Timm, Steven [Fermilab; Bernabeu, Gerard [Fermilab; Noh, Seo-Young [KISTI, Daejeon

    2014-11-12

    FermiCloud is a private cloud developed by the Fermi National Accelerator Laboratory for scientific workflows. The Cloud Bursting module of the FermiCloud enables the FermiCloud, when more computational resources are needed, to automatically launch virtual machines to available resources such as public clouds. One of the main challenges in developing the cloud bursting module is to decide when and where to launch a VM so that all resources are most effectively and efficiently utilized and the system performance is optimized. However, based on FermiCloud’s system operational data, the VM launching overhead is not a constant. It varies with physical resource (CPU, memory, I/O device) utilization at the time when a VM is launched. Hence, to make judicious decisions as to when and where a VM should be launched, a VM launch overhead reference model is needed. The paper is to develop a VM launch overhead reference model based on operational data we have obtained on FermiCloud and uses the reference model to guide the cloud bursting process.

  2. Medial Epicondyle Fractures in the Pediatric Overhead Athlete.

    Science.gov (United States)

    Cruz, Aristides I; Steere, Joshua T; Lawrence, J Todd R

    2016-06-01

    The medial epicondyle serves as the proximal attachment of the medial ulnar collateral ligament and the origin of the flexor pronator musculature and as such it is responsible for resisting the main static and dynamic restraints to valgus force at the elbow. Fractures through the physis in the developing elbow are common and treatment remains controversial. Biomechanical modeling predicts that anterior should be the direction of greatest displacement. Anatomic considerations predict that anterior displacement should have the greatest effect on elbow stability and range of motion making the ulnar collateral ligament too loose in flexion and too tight in extension and potentially leading to valgus laxity in flexion and a block to full extension. In the elite overhead athlete, where elbow stability is critical both for sports performance and the long-term health of the elbow, assessment of anterior displacement is thus theoretically an important consideration. Standard radiographic views cannot adequately assess anterior displacement. Specialized radiographs and 3-dimensional modalities such as computerized tomography and magnetic resonance imaging can adequately assess anterior displacement and in the overhead athlete can sometimes aid in the decision-making process. Here, we present a review of the current literature and the rationale for a treatment algorithm for medial epicondyle fractures in the skeletally immature overhead athlete.

  3. A Method of Unbalanced Current Off-line Test for High-voltage Capacitors in Converter Station%换流站高压电容器不平衡电流离线测试方法

    Institute of Scientific and Technical Information of China (English)

    吴鹏; 摆亲; 刘志远; 张振宇

    2014-01-01

    对换流站高压电容器不平衡电流理论计算进行简单推导,并以不同工频电压作用下不平衡电流的线性关系为基本原理,介绍了低工频电压下离线试验测试不平衡电流大小与理论计算值之间的差别,并通过对误差由浅入深地分析,从而得出现场运行维护人员提高不平衡电流测试值准确性的关键方法,即合理优化现场试验接线以减少电磁干扰,并适当对比理论计算值与离线试验测试值的方法,从而确保桥臂不平衡电流离线测试值的准确性。通过电容器调整或更换,满足了离线测试不平衡电流大小要求,能保障设备投入电网后的稳定运行。%This paper describes the unbalanced current theoretical formula of the high-voltage capacitors in a converter station, and with the linear relationship of unbalanced current under the action of different power frequency voltages as the basic principle,the difference between the unbalanced current theoretical value and off-line testing value under low power frequency voltage is accounted for.Through analysis of the cause of the difference from shallow to deep,the conclusion is reached that the key method by which the field maintenance personnel can improve the accuracy of unbalanced current test is through rational and optimized test wiring to reduce electromagnetic interference and appropriately compare theoretical value with off-line test value to ensure the accuracy of the bridge arm unbalanced current off-line test value.Through the capacitor adj ustment or replacement,the off-line test values of the unbalanced current are up to requirement for ensuring stable equipment work in operation.

  4. 嵌入式低压电力线通信风机控制系统设计%Embedded Control System Design for Fan Based on Low-Voltage Power Lines communication

    Institute of Scientific and Technical Information of China (English)

    曾素琼

    2012-01-01

    Low-Voltage power lines carrier communication using the existing power lines, replacing the pain of re-wiring, it is ideal for intelligent control system induced by ventilation. Control system of low-voltage power lines carrier communication for inductive ventilation are designed based on LPC2132 (ARM7) and ST7538. The main circurts are designed, including controller o f circuit connection diagram based on the LPC2132 and ST7538, the interface circuit design of voltage power lines carrier communication; the module circuit of CO detection and smoke detection; Discussed the master/slave communication process and designed the fan' control and system software. The system is mainly used for underground parking, underground shopping malls, stadiums and other large -scale place. The design has the simple construction, low cost, plug-and-play, anti-interference ability* debugging maintain convenience etc, it has some practical value.%低压电力线载波通信利用原有供电线路,免去重新布线之苦,非常适用于诱导通风智能控制系统;设计了基于LPC2132(ARM7)与ST7538的低压电力线载波通信诱导风机控制系统,对系统的主要电路作了设计,包括基于LPC2132与ST7538的控制器电路连接图、电力线载波通信接口、CO检测、烟雾检测等模块电路;讨论了主/从通信过程、风机控制及系统的软件设计;系统主要用于地下停车场、地下商场、大型场馆等需自动通风及防火的场所;该设计方案与传统的总线式通风控制系统相比,具有系统构建简单、成本低、即插即用、抗干扰能力强、调试维护方便等优点,具有一定实用价值.

  5. 220kV高压输电线路检修的危险点分析%220 kv High-voltage Transmission Line Maintenance of Dangerous Point Analysis

    Institute of Scientific and Technical Information of China (English)

    郭海涛

    2015-01-01

    在作业过程中危险可能存在的具体地点、具体方位及具体场所和具体动作称危险点。针对220kV高压输电线路中存在的危险点,对自然灾害、天气环境情况、线路自身缺陷、线路维修不善、输电线路铺设设计不合理等常见情况进行了科学分析,并提出了相应的预防控制办法。%In the process of operation risk the exact location of the possible,specific position and specific place and specific movement to call the danger point.In 220kv high-voltage transmission lines that exist in the dangerous points,to natural disasters,weather conditions,poor bird,line itself defects,line maintenance,violate compasses operation,artificial damage, transmission line laying design unreasonable,and other common situation has carried on the scientific analysis,and put forward the corresponding prevention and control measures.

  6. Accurate Switched-Voltage voltage averaging circuit

    OpenAIRE

    金光, 一幸; 松本, 寛樹

    2006-01-01

    Abstract ###This paper proposes an accurate Switched-Voltage (SV) voltage averaging circuit. It is presented ###to compensated for NMOS missmatch error at MOS differential type voltage averaging circuit. ###The proposed circuit consists of a voltage averaging and a SV sample/hold (S/H) circuit. It can ###operate using nonoverlapping three phase clocks. Performance of this circuit is verified by PSpice ###simulations.

  7. Research and Application of Intelligent Birds Dispersing System for High Voltage Transmission Line%高压输电线路智能驱鸟防治系统的研究与应用

    Institute of Scientific and Technical Information of China (English)

    赵志刚; 许文广; 李俭; 康淑丰; 刘威伟

    2015-01-01

    文章对高压输电线路智能驱鸟防治系统进行了分析研究,提出了高压输电线路智能驱鸟防治系统技术,智能驱鸟系统采用微波感应位移模块,利用多普勒雷达(Doppler Radar)原理设计的微波移动物体探测器,微波感应位移模块信号处理采用单片机程序分析,鸟进入雷达探测区域可迅速报警,启动装置。通过在河北500kV输电线路上应用表明,该系统运行稳定可靠,采集数据准确,驱鸟措施有效明显。%The high voltage transmission line intelligent birds dispersing control system was analyzed, the technique of high voltage transmission line intelligent birds dispersing control system was proposed. The intelligent birds dispersing system adopted the microwave induced displacement module, using Doppler Radar, the principle of design of microwave moving object detector, microwave induced displacement signal processing module by single chip microcomputer program analysis, the bird into the radar detection region can rapidly alarm, initiating device. Through application in 500kv transmission lines in south power network in Hebei province shows that the system runs stable and reliable, accurate data gathering, and birds dispersing measures worked effectively.

  8. Energy storage system in medium-sized voltage lines for the integration of decentralized fluctuating energy sources; Energiespeicher im Niederspannungsnetz zur Integration dezentraler, fluktuierender Energiequellen

    Energy Technology Data Exchange (ETDEWEB)

    Bodach, M.

    2006-06-30

    The solar radiation fluctuates due to atmospheric and planetary influences. Concerning PV systems, the changes from dark clouds to clear sky result in fast and very deep fluctuations of the time behaviour of the power output fed into the low voltage (LV) network by DC-AC-Converters. On the example of a daily recorded global radiation curve with a very short sampling time (regular interval time 1 s) the paper shows that short-term sags of the solar radiation are possible up to 80% of the previous value as a result of sudden and intensive changes of the density of the clouds. These disturbances of the quality of the generated electric power are directly transformed into the LV grids. If the number of PV systems connected to existing LV networks rises essentially, the fluctuating photovoltaic energy generation will achieve a very high importance and therefore not only the well-known, but also a lot of new problems will occur. They have already been investigated theoretically in different papers and they have also been proven quantitatively by own simulations. Improvements of the energy quality at the point of common coupling will be possible if the grid-coupled PV power plants are supplemented with suitable intelligent storage systems bridging the short-term sags. So the influence of the fluctuating radiation on the generated power can be fundamentally reduced. The developed intelligent short-term storage system smoothes out the generated power of the PV system by means of a storage. It is based on the very high capacity of an electric double layer (UltraCap, produced by EPCOS) and includes a complex electronic control system. The UltraCap has the required storing characteristics and has been adjusted to the system voltage by a highly sophisticated microprocessor controlled DC/DC-converter system. Such an intelligent storage system can also be used for the connection of other decentralised power generation units (e.g. fuel cells, block-unit heating power plant) to the

  9. Smart Energy Gateway (SEG) for optimized energy flow control in new generation of vehicle's powernet with on-line multi voltage power sources

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Ignacio; Ferre, Antoni [LEAR Corporation, Tarragona (Spain)

    2010-07-01

    CO{sub 2} emissions reduction leads OEMs as a matter of facts to search alternative power trains that optimize the overall electrical power flow starting from fixed installed energy basis specified for each vehicle to accomplish with expected performance. Optimization comes from uses of already existing energy sources in the vehicle (solar radiation, exhaust gas heat waste recovery, etc.) and external ones available in certain vehicle modes as parking (grid, DC charge system, etc.). Particularity of these sources is different nature and optimum working ranges in terms of voltage and current and the mismatching among them in the expected vehicle conditions or modes. To solve this lack of smart power management in the net, this paper presents SEG (Smart Energy Gateway), a MIPEC based concept doted of Intelligence and Energy Management algorithms able to carry out by actuation over Si switches and DCDC converter working points the functionality of smartly drive the power from and to the requested source/loads at any time. Also system overview is presented along with state flow charts, and practical concreted topologies for implementation. (orig.)

  10. Application of RTK Intelligent Positioning System in Project of High Voltage Transmission Line%GPS -RTK 在高压输电线路工程中的应用

    Institute of Scientific and Technical Information of China (English)

    王晓静; 朱宝训; 何保喜

    2014-01-01

    In survey project of high voltage transmission line , due to effect of vegetations , the indivisibility condition is very poor;conventional surveying method results in not only a high cost , but also a long construction period and high surveying workload , there-fore it is difficult to ensure the restored line to be in consistence with the original straight line .With the aid of GPS ( Global Positioning System) technology, survey project of high voltage transmission line can be accomplished conveniently , swiftly, and accurately.The real-time dynamic measurement of RTK ( Real Time Kinematic ) intelligent positioning system discussed in this paper is characterized by its functions of calculating relative relationships among points , lines and surfaces as well as the function of visual graphical display , and is able to accomplish construction survey , record, as well as high intelligent and integration in calculation .Compared with tradi-tional surveying techniques , it is free from constraints of visual conditions , and can be applied to long distance , while maintaining high speed and high precision .In general, real-time dynamic measurement of RTK intelligent positioning system can significantly improve the production efficiency in engineering applications .%在高压输电线路工程测量中,由于受植被影响,通视条件极差;常规测量方法不但赔偿费用高,而且工期长,测量工作量大,很难保证恢复后的直线与原直线一致。随着全球定位系统GPS ( Global Positioning System )的广泛应用,可借助GPS定位技术方便、快速、准确地进行测量。本文论述的实时动态测量RTK ( Real Time Kine2 matic)智能定位系统,具有点、线、面之间相对关系的计算功能及直观的图形显示功能,实现了施工测量、记录、计算的高度智能化、一体化;与传统的测量技术相比,不受通视条件的限制,测量的距离远、速度快、精度高;在

  11. Design of a distributed high and low voltage line to prevent electricity theft%一种分布式高低压线路防窃电设计

    Institute of Scientific and Technical Information of China (English)

    肖监; 王玉萍; 桂专; 张秋雁

    2016-01-01

    At present the smart electricity consumption system, It mainly depend on the Remote terminal and smart me-ter to prevent electricity theft, It just use the low-voltage data, caused the instability of system, and high Rate of missing or errors. To solve this problem, design a field distributed system, it based on the Fault indicator and Low-voltage line collection, remote terminal judge the operating condition systematically. It can monitor all kinds of electricity stealing activities. It has the characteristics of high reliability, low cost and convenient maintenance. It can help the system to monitor anti-electricity theft.%目前智能用电系统中,防窃电主要依赖低压侧远方终端和电表判断,单一使用低压侧数据判断,系统不可靠,误报,漏报率高。针对该问题,设计了一种基于故障指示器和低压线路采集相结合,远方终端系统判断高压和低压数据,可有效监测各类常见窃电异常,系统可靠性高,投入成本低,运维便利,能为现有系统提供有效窃电监测。

  12. Development of a Technique for Representing Lightning Arresters in the Surge Simulations based on the FDTD Method and its Application to the Calculation of Lightning-Induced Voltages on a Distribution Line

    Science.gov (United States)

    Tatematsu, Akiyoshi; Noda, Taku

    Recently, the FDTD (Finite Difference Time Domain) method, which directly solves Maxwell's equations, has been applied to lightning surge problems involving electrical wires in three-dimensional arrangements, such as power and telecommunication circuits. Lightning arresters are installed to protect the circuits from abnormal voltages due to lightning, for example. We have already proposed a technique for representing a lightning arrester in the FDTD method. However, this technique simply represents the V-I characteristics of the arrester using just three parameters and requires a method for avoiding the numerical oscillation due to the nonlinear characteristics of the arrester. In this paper, we propose a new technique for representing the V-I characteristics of the arrester in detail using the piecewise linear function defined by several points and for improving the numerical stability without the method for avoiding the numerical oscillation. Using a test circuit, the proposed technique is validated by comparing the results calculated by the FDTD method with those by the EMTP (ElectroMagnetic Transients Program) which is a circuit-theory-based simulation program. Finally, as an example of applying the proposed technique, we calculate lightning-induced voltages on a distribution line with a lightning arrester. The calculated results by the FDTD method agree well with those by a conventional method based on circuit theroy.

  13. Induced Voltage and Current of 750kV Double Circuit Maintenance Transmission Line%750kV同塔双回线路检修线路感应电压、电流研究

    Institute of Scientific and Technical Information of China (English)

    曾林平; 文武; 阮江军; 张思寒

    2012-01-01

    Based on Lanzhou East-Pingliang 270km-long 750kV double circuit transmission line on the same tower, this paper researched the magnitude and distribution characteristics of the induced voltage of maintenance line and induced current of grounding wire in order to provide reference for the formulation of maintenance program and the selection of temporary grounding wire. The results earl also be applied in Pingliang-Qianxian 750kV double circuit transmission line.%以兰州东—平凉段270 km长的750 kV同塔双回输电线路为例,研究了检修线路的感应电压及临时接地线的感应电流的大小及分布特征,为检修方案的制定及临时接地线的选型提供参考,研究结果也可用于平凉—乾县段的750 kV同塔输电线路。

  14. 厂外排水管道交流稳态干扰防护设计%Protection Design against AC Steady-state Interference for Water Pipeline near High-voltage Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    程明; 牟华; 黄春蓉; 张平

    2013-01-01

    AC steady-state interference may affect the water pipeline near high-voltage transmission lines. Referring to some related standards, the mitigation objective and protection effect of the AC interference were analyzed, and the Right of Way (ROW) package was used to build modeling and calculation around the mitigation. The calculation results can guide the engineering design.%高压输电线路附近的厂外排水管道可能面临交流稳态干扰影响.结合相关标准要求,对交流干扰缓解目标和防护效果进行探讨分析,并利用自动计算软件包(ROW)分别对缓解前后进行建模计算分析.计算分析结果可以指导工程设计.

  15. Arrester installations for improving the lightning performance of double circuits distribution lines

    Energy Technology Data Exchange (ETDEWEB)

    Thanasaksiri, T. [ChiangMai Univ., ChianMai (Thailand). Dept. of Electrical Engineering

    2007-07-01

    The Provincial Electricity Authority (PEA) of Thailand serves 99 per cent of the the country's power customers. The main power distribution lines used by PEA consist of 22 and 33 kV high voltage distribution systems and a 400/230 V low voltage system. In order to supply more energy and for economic reasons, distribution lines for industrial and commercial loads consist of double circuits. Lightning strikes on either circuit can affect the other. There are different methods that can be used to reduce the number of flashovers on lines and improve the lightning performance of lines. This paper presented a method for improving the lightning performance of 22 kV double circuit overhead distribution lines by means of arrester installations. The study focused both on partial and full arrester installations and considered arrester energy discharge. The paper discussed the electromagnetic transients program (EMTP) model of systems studied, including a pole and footing impedance model; a line model; an arrester model; an insulator model; a flashover model; and a lightning source model. The studied configurations included pole structure types; phase and ground wire conductors; lightning arresters; insulators; and ground rods. It was concluded that full installation provides better lightning performance compared to partial installation. 7 refs., 8 tabs.

  16. Shoulder injuries in overhead sports; Schultergelenkverletzungen bei Ueberkopfsportarten

    Energy Technology Data Exchange (ETDEWEB)

    Woertler, K. [Technische Universitaet Muenchen (Germany). Institut fuer Roentgendiagnostik

    2010-05-15

    Overhead sport places great demands on the shoulder joint. Shoulder pain in overhead athletes and throwers can in the majority of cases be attributed to lesions resulting from chronic overuse of tendons and capsuloligamentous structures or to sequels of microinstability and secondary impingement. Due to its great impact on therapeutic decisions, imaging in athletes with unclear shoulder pain is a challenge. In this connection, magnetic resonance (MR) arthrography represents the cross-sectional imaging modality of first choice, as it allows depiction and exclusion of pathologic alterations of all relevant joint structures with sufficient confidence. This article reviews the biomechanical and clinical aspects and MR arthrographic features of the most common shoulder pathologies in overhead athletes, including biceps tendinopathy, superior labral anterior-posterior (SLAP) lesions, rotator cuff lesions, as well as extrinsic and intrinsic impingement syndromes. (orig.) [German] Ueberkopfsportarten stellen grosse Anforderungen an das Schultergelenk. Schulterbeschwerden bei Ueberkopf- und Wurfsportlern koennen in der Mehrzahl der Faelle auf eine chronische Ueberlastung von Sehnen und Kapsel-Band-Strukturen oder auf die Folgen einer Mikroinstabilitaet und sekundaerer Impingementsyndrome zurueckgefuehrt werden. Wegen ihres grossen Einflusses auf die Therapieentscheidung stellt die Bildgebung bei Athleten mit unklaren Schulterbeschwerden eine Herausforderung dar. Die MR-Arthrographie ist in diesem Zusammenhang als Schnittbildverfahren der ersten Wahl anzusehen, da sie den Nachweis bzw. Ausschluss pathologischer Veraenderungen aller relevanten Gelenkstrukturen mit ausreichender Sicherheit ermoeglicht. Dieser Artikel gibt eine Uebersicht ueber biomechanische und klinische Aspekte sowie MR-arthrographische Befunde der haeufigsten Schultergelenkpathologien bei Ueberkopfsportlern, wie Bizepstendinopathie, Superior-labral-anterior-posterior- (SLAP-)Laesionen, Laesionen der

  17. Path-sensitive analysis for reducing rollback overheads

    Science.gov (United States)

    O'Brien, John K.P.; Wang, Kai-Ting Amy; Yamashita, Mark; Zhuang, Xiaotong

    2014-07-22

    A mechanism is provided for path-sensitive analysis for reducing rollback overheads. The mechanism receives, in a compiler, program code to be compiled to form compiled code. The mechanism divides the code into basic blocks. The mechanism then determines a restore register set for each of the one or more basic blocks to form one or more restore register sets. The mechanism then stores the one or more register sets such that responsive to a rollback during execution of the compiled code. A rollback routine identifies a restore register set from the one or more restore register sets and restores registers identified in the identified restore register set.

  18. Characterization of overhead projector transparency as heavy ion detector

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, S.; Raju, J.; Choubey, P.P.; Dwivedi, K.K. (North Eastern Hill Univ., Shilling (India). Dept. of Chemistry)

    1991-01-01

    In an attempt to characterize overhead projector transparency (OPT) as a detector material we have carried out its elemental analysis. It has been found to be a triacetate. The optimum etching conditions were found out and the bulk etch rate V{sub G} and its activation energy E{sub a} have been determined. The maximum etchable track lengths of {sup 252}Cf fission fragments and {sup 132}Xe ranges at 14.5 and 5.9 MeV/u in OPT have been measured. Further work on correlation of V{sub T} and dE/dx is in progress. (author).

  19. Shoulder muscle imbalance and subacromial impingement syndrome in overhead athletes.

    Science.gov (United States)

    Page, Phil

    2011-03-01

    Subacromial impingement is a frequent and painful condition among athletes, particularly those involved in overhead sports such as baseball and swimming. There are generally two types of subacromial impingement: structural and functional. While structural impingement is caused by a physical loss of area in the subacromial space due to bony growth or inflammation, functional impingement is a relative loss of subacromial space secondary to altered scapulohumeral mechanics resulting from glenohumeral instability and muscle imbalance. The purpose of this review is to describe the role of muscle imbalance in subacromial impingement in order to guide sports physical therapy evaluation and interventions.

  20. 暂态边界电压法在线测试全钒液流电池阻抗%On-line resistance measurement for all vanadium redox flow battery by transient-boundary voltage method

    Institute of Scientific and Technical Information of China (English)

    潘建欣; 廖玲芝; 谢晓峰; 王树博; 王金海; 尚玉明; 周涛

    2012-01-01

    国内首次采用暂态边界电压法在线研究了全钒液流电池(VRB)的特性,建立了由电压源、电阻以及一个电阻与电容并联的3部分串联而成的等效电路模型;研究了电流密度和荷电状态(SOC)对等效电路元件的影响。实验结果表明,极化阻抗随电流密度的增加有轻微下降,在充电初期和放电末期达到最大值。与极化阻抗相比,充、放电过程中的欧姆阻抗最大,是导致电压损失的主要因素,分别为1.905Ω.cm2和2.139Ω.cm2,暂态边界电压法是一种简单且有效的表征全钒液流电池性能的新方法。%A single cell of vanadium redox flow battery(VRB) was investigated on-line by the transient-boundary voltage method.An equivalent circuit model was established using the voltage source,resistor,and a resistor in parallel with the capacitance of three-part series.The effects of current density and state of charge(SOC) on equivalent circuit components values were investigated.The experimental results showed that the polarization resistance decreased slightly with increasing current density,and reached its maximum in the beginning of charge and the end of discharge.Compared with polarization resistance,ohm impedance in the charge/discharge process was the highest respectively 1.905 cm2and 2.139 cm2.It was the main factor leading to voltage loss.The transient boundary voltage method is a simple and effective way of characterizing performance of vanadium redox flow battery.

  1. High Voltage Seismic Generator

    Science.gov (United States)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

  2. Model for the ready definition and approximate comparison of alternative high voltage transmission systems

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-01

    A model of generic overhead transmission systems in the range of 362 to 1200 kV ac, and +-400 to +-800 kV dc is developed. Such generic systems are to include (a) transmission from generation to load, and (b) interconnection of two large integrated systems, with and without the existence of an underlying, lower voltage network in either case. The model provides a means whereby an engineer with some experience in power systems planning can make a reconnaissance study of alternatives within a relatively short span of time and with fair accuracy. Given an amount of power to be transferred over a specified distance, the model can be used: to define the workable alternatives in terms of voltages, number of lines, series compensation, and certain other factors affecting transfer capability; to delineate other salient features of the selected alternatives, notably shunt compensation requirements; and to compare the alternatives in terms of potentially relevant benefits and costs. The significant properties of the model, the basis and assumptions necessary to its formulation, instructions for its use, and inherent limitations upon the accuracy to be expected are described.

  3. 基于DSP和小波变换的电压暂态扰动在线监测方法研究%Study of voltage transient disturbance on-line detection based on DSP and wavelet transform

    Institute of Scientific and Technical Information of China (English)

    王飞; 黄细霞; 张兵; 骆秀江

    2015-01-01

    A voltage disturbance detection device based on DSP2812 is designed in this paper. A method of transient voltage disturbance detection based on DSP and wavelet transform is studied. The system takes a Hall sensor and the parallel A/D con⁃verter chip as its acquisition circuit,and a kind of digital signal processing chip TMS320F2812 as its core information process⁃ing unit,by which the design of DSP and its peripheral circuit are achieved. The discrete wavelet transform(DWT)is adopted to detect transient voltage disturbance on line and realize wavelet algorithm in DSP. Software modules including the main pro⁃gram module,A/D module,interrupt module,communication module and so on were designed. Its simulation experiment was performed in Matlab to choose suitable wavelet functions and to locate disturbance position by utilizing DB4 wavelet in Matlab. The signal generator is used to produce the signal including transient voltage disturbance. The power acquisition and real⁃time analysis of transient voltage disturbance can be realized simultaneously by the strong operation ability of DSP and the effective DWT algorithm. The contrast test shows that the system has high precision,high data processing speed and perfect capability for real⁃time detection of transient voltage disturbance.%设计了一款基于DSP2812的电压暂态扰动在线检测装置,研究了基于DSP和小波变换的电压暂态扰动在线检测方法。该装置通过霍尔传感器和模数转换芯片采集电信号,以高性能数字信号处理芯片TMS320F2812为核心信息处理单元,完成了DSP及其外围电路设计。采用小波变换在线检测电压暂态扰动,并在DSP中实现了小波算法,软件还包括主程序模块、A/D采集模块、中断模块、上位机处理模块和通讯模块等设计。实验首先在Matlab中进行了仿真实验,选取合适的小波函数,利用Matlab中的DB4小波对扰动进行定位;然后再利用信号发生

  4. Applications of high-temperature superconductors in power technology[8470 High-current and high-voltage technology: power systems; power transmission lines and cables;

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R [Energy Technology Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2003-11-01

    Since the discovery of the first high-temperature superconductors (HTSs) in the late 1980s, many materials and families of materials have been discovered that exhibit superconductivity at temperatures well above 20 K. Of these, several families of HTSs have been developed for use in electrical power applications. Demonstration of devices such as motors, generators, transmission lines, transformers, fault-current limiters, and flywheels in which HTSs and bulk HTSs have been used has proceeded to ever larger scales. First-generation wire, made from bismuth-based copper oxides, was used in many demonstrations. The rapid development of second-generation wire, made by depositing thin films of yttrium-based copper oxide on metallic substrates, is expected to further accelerate commercial applications. Bulk HTSs, in which large single-grain crystals are used as basic magnetic components, have also been developed and have potential for electrical power applications.

  5. Kinematic Design of a Radius-Variable Gripper with 1-D.O.F. used in High-voltage Hot-line Cleaning Robot

    Directory of Open Access Journals (Sweden)

    Yi Gu

    2008-11-01

    Full Text Available This paper presents the design of a novel radius-variable-gripper (RVG for use as end-effector of highvoltage hot-line cleaning robot (HVCR. A eight-bar linkage mechanism is proposed to obtain the aim of 1-dof acutuation. According to the shape of insulators, the dimension design and kinematic analysis of RVG have been carried out. The optimization is performed to locate the joint points of arm segments, on which the brushes are mounted, approximately on the position circles in the whole opening-and-closing process of RVG. The prototype has been given finally, and it is showed that RVG is feasible to this special application.

  6. A Distance Protection Scheme Not Affected by Transient Characteristic of Capacitor Voltage Transformer for HV Long Transmission Line%不受电容式电压互感器暂态特性影响的距离保护

    Institute of Scientific and Technical Information of China (English)

    焦在滨; 齐倩; 杨黎明; 王优胤; 宁荣

    2014-01-01

    受电容式电压互感器(capacitive voltage transformer, CVT)暂态特性的影响,高压输电线路距离保护易发生暂态超越而误动,影响电力系统的安全稳定运行。提出了一种不受 CVT 暂态特性影响的距离保护新原理。该原理以 CVT能够正确传变工频量为基础,通过基于矩阵束的准确工频量提取方法计算保护安装处电压电流的工频量,利用贝瑞龙模型计算长距离输电线路整定点处的电压和电流,最终以整定点为观测点,通过传统的距离保护算法与方向元件配合确定故障点的位置,该原理不受CVT暂态特性的影响,同时考虑了长距离输电线路分布参数效应对距离保护的影响,具有较好的性能,仿真结果验证了所提算法的有效性。%Affected by transient characteristic of capacitor voltage transformer (CVT), the distance protection for HV transmission line is easily to mal-operate due to transient overreach, thus the secure and stable operation of power grid is affected. A new distance protection scheme that is not affected by the transient characteristics of CVT is proposed and its principle is as following:firstly, on the basis that the CVT can transmit and transform power frequency phasor, by means of the matrix pencil based accurate power frequency phasor extraction method the power frequency phasors of voltage and current at the position where the protection is installed are calculated;secondly, the voltage and current at the position of the long distance transmission line, where the protection is set, are calculated by Bergeron model; finally, coordinating with directional element and taking the setting point as the observation point, the fault point is located by traditional distance protection algorithm. The proposed principle is not affected by transient characteristic of CVT and the impacts of distributed parameters of the long distance transmission line are taken into account, thus the

  7. CLOMP: Accurately Characterizing OpenMP Application Overheads

    Energy Technology Data Exchange (ETDEWEB)

    Bronevetsky, G; Gyllenhaal, J; de Supinski, B R

    2008-11-10

    Despite its ease of use, OpenMP has failed to gain widespread use on large scale systems, largely due to its failure to deliver sufficient performance. Our experience indicates that the cost of initiating OpenMP regions is simply too high for the desired OpenMP usage scenario of many applications. In this paper, we introduce CLOMP, a new benchmark to characterize this aspect of OpenMP implementations accurately. CLOMP complements the existing EPCC benchmark suite to provide simple, easy to understand measurements of OpenMP overheads in the context of application usage scenarios. Our results for several OpenMP implementations demonstrate that CLOMP identifies the amount of work required to compensate for the overheads observed with EPCC.We also show that CLOMP also captures limitations for OpenMP parallelization on SMT and NUMA systems. Finally, CLOMPI, our MPI extension of CLOMP, demonstrates which aspects of OpenMP interact poorly with MPI when MPI helper threads cannot run on the NIC.

  8. TAUOVERSUPERMON: LOW-OVERHEAD ONLINE PARALLEL PERFORMANCE MONITORING

    Energy Technology Data Exchange (ETDEWEB)

    SOTTILE, MATTHEW JOSEPH [Los Alamos National Laboratory; NATARAJ, AROON [Los Alamos National Laboratory; MALONY, ALLEN [Los Alamos National Laboratory; MORRIS, ALAN [Los Alamos National Laboratory; SHENDE, SAMEER [Los Alamos National Laboratory

    2007-01-30

    Online or Real-time application performance monitoring allows tracking performance characteristics during execution as opposed to doing so post-mortem. This opens up several possibilities otherwise unavailable such as real-time visualization and application performance steering that can be useful in the context of long-running applications. Two fundamental components that constitute such a performance monitor are the measurement and transport systems. The former captures performance metrics of individual contexts (processes, threads). The latter enables querying the parallel/distributed state from the different contexts and also allows measurement control. As HPC systems grow in size and complexity, the key challenge is to keep the online performance monitor scalable and low overhead while still providing a useful performance reporting capability. We adapt and combine two existing, mature systems - Tuning and Analysis Utility (TAU) and Supermon - to address this problem. Tau performs the measurement while Supermon is used to collect the distributed measurement state. Our experiments show that this novel approach of using a cluster-monitor, Supermon, as the transport for online performance data from Tau leads to very low-overhead application monitoring as well as other beneits unavailable from using a traditional transport such as NFS.

  9. Does scapular positioning predict shoulder pain in recreational overhead athletes?

    Science.gov (United States)

    Struyf, F; Nijs, J; Meeus, M; Roussel, N A; Mottram, S; Truijen, S; Meeusen, R

    2014-01-01

    The objective of this prospective study is to investigate possible scapular related risk factors for developing shoulder pain. Therefore, a 2-year follow-up study in a general community sports centre setting was conducted. A sample of convenience of 113 recreational overhead athletes (59 women and 54 men) with a mean age of 34 (17-64; SD 12) years were recruited. At baseline, visual observation for scapular dyskinesis, measured scapular protraction, upward scapular rotation and dynamic scapular control were evaluated. 22% (n=25) of all athletes developed shoulder pain during the 24 months following baseline assessment. The Mean Shoulder Disability Questionnaire (SDQ) score for the painful shoulders was 34.8 (6.3-62.5; SD 17.4). None of the scapular characteristics predicted the development of shoulder pain. However, the athletes that developed shoulder pain demonstrated significantly less upward scapular rotation at 45° (p=0.010) and 90° (p=0.016) of shoulder abduction in the frontal plane at baseline in comparison to the athletes that remained pain-free. In conclusion, although these scapular characteristics are not of predictive value for the development of shoulder pain, this study increases our understanding of the importance of a scapular upward rotation assessment among recreational overhead athletes.

  10. The Motion Planning of Overhead Crane Based on Suppressing Payload Residual Swing

    Directory of Open Access Journals (Sweden)

    Liu Hua-sen

    2016-01-01

    Full Text Available Since the overhead crane system is subject to under actuation system due to that overhead crane and payload are connected by flexibility wire rope. The payload generates residual swing when the overhead crane is accelerating/ decelerating the motions. This may cause trouble for the payload precise positioning and motion planning. Hence, an optimization input shaping control method is presented to reduce the under actuated overhead crane’s payload swing caused via the inertia force. The dynamic model of the overhead crane is proposed according to the physics structure of the crane. The input shaper based on the motion planning of the crane is used as the feed forward input to suppress payload residual swing. Simulation and experiment results indicate that the ZV input shaper and ZVD input shaper can reduce the payload swing of the overhead crane.

  11. Development of sensorless easy-to-use overhead crane system via simulation based control

    Science.gov (United States)

    Tagawa, Yasutaka; Mori, Yoshihito; Wada, Masaomi; Kawajiri, Eisaku; Nouzuka, Kazuma

    2016-09-01

    This paper describes the newly developed overhead crane which has a sensorless vibration control system. Generally, loads which are carried by the overhead cranes are easy to vibrate and only skilled people can operate the cranes. Therefore, a lot of studies have been done to solve this problem by using feedback control with vibration sensors. However vibration sensors often break down in severe industrial environment and more reliable control systems are required. For this reason, we have been developing sensorless control system for overhead cranes. In this paper, we firstly introduce basic idea of simulation based control which is called IDCS, then overview and modeling of the overhead crane is presented. Next, the control system design of the overhead crane is discussed, and experimental results are shown for real overhead crane with 2 axes.

  12. Diagnosis on line and off line of induction motors of low, medium and high voltage; Diagnostico en linea y fuera de linea de motores de induccion de baja, mediana y alta tension

    Energy Technology Data Exchange (ETDEWEB)

    Carvajal, Francisco Antonio; Ramirez, Jose Manuel; Arcos, Luis Fernando [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    1999-07-01

    The induction motors of low, medium and high voltage are the electrical equipment of greatest application in industry. The importance which they have in the different productive processes does necessary to assure its operative continuity. The anticipated detection of a possible cause of fault allows to plan, with maintenance aims, the programmed removal of the motor. In this article are presented the results of the activities nowadays performed by Management of Electrical Equipment of the Instituto de Investigaciones Electricas (IIE) for the development and application of online diagnosis techniques for induction motors up to 13.8 kV. [Spanish] Los motores de induccion de baja, mediana y alta tension son los equipos eletricos de mayor aplicacion en la industria. La importancia que tienen en los diferentes procesos productivos hace necesario asegurar su continuidad operativa. La deteccion anticipada de una posible causa de falla permite planear, con fines de mantenimiento, la remocion programada del motor. En este articulo se presentan los resultados de las actividades que realiza actualmente la Gerencia de equipos Electricos del Instituto de investigaciones Electricas (IIE) para el desarrollo y la aplicacion de tecnicas de diagnostico en linea para motores de induccion de hasta 13.8 kV.

  13. New longitudinal differential protection scheme for four-circuit transmission line with different voltage grades%不同电压等级的四回线的纵联差动保护方案

    Institute of Scientific and Technical Information of China (English)

    陈金熠; 范春菊; 刘玲

    2011-01-01

    To solve the problem that the traditional longitudinal differential protection used in four-circuit transmission line on the same pole with different levels will be seriously affected by coupling inductance, a new longitudinal differential protection scheme based on inverse-sequence negative sequence difference current is proposed. Four-circuit transmission lines with different voltage grades generally consist of two double circuit transmission lines at the same tower. However, when line parameters are symmetry, the inverted sequence current is zero when the system operates normally or external faults occur. Once internal faults occur, there is inverted current in the transmission line, and the sum of inverted current at both sides is large, so the differential protection based on inverted current can operate correctly. For this method, the reliability and sensitivity under big fault resistance can be kept. And it will not be affected by capacitive current when it is applied to the main protection of four-circuit transmission line with different voltage grades. The theoretical analysis and EMTP simulation results show that the proposed principle is correct and reliable.%为克服传统纵联差动保护运用在不同电压等级的同杆四回线中容易受到耦合电感的影响,提出了基于反序负序差电流的纵联差动保护方案.不同电压等级的四回线由两个不同电压的等级的同杆双回线构成.对于同杆双回线路,当线路参数完全对称时,系统正常运行或是外部故障时,反向电流分量为零;而当双回线内部故障时,反向环流量存在于双回线的内部,双回线两侧反向电流之和比较大,可以构成基于反向环流量的纵联差动保护.该保护方案不仅可以避开电容电流对于差动保护的影响,而且有较强的抗过渡电阻能力.将该保护方案应用到不同电压等级的四回线的主保护中,保护性能优越,不仅可以可靠动作,还避免了电容

  14. Transient Voltage Stability Analysis of East China Receiving-End Power Grid With Multi-Infeed HVDC Transmission Lines%多直流馈入华东受端电网暂态电压稳定性分析

    Institute of Scientific and Technical Information of China (English)

    邵瑶; 汤涌; 郭小江; 周勤勇

    2011-01-01

    基于2015年“三华”特高压规划电网的丰大运行方式,利用短路比和多馈入短路比指标分析了华东受端电网的强度,并讨论了受端系统网架调整和直流系统落点位置对短路比/多馈入短路比的影响。采用PSD-BPA暂态稳定程序,分析了华东受端电网在各种故障下的暂态电压稳定性。结果表明:直流系统落点位置对华东受端电网强度的影响较大;交直流系统单一故障、受端特高压交流通道和逆变站换流母线附近线路发生三相永久性短路跳双回故障,大部分直流系统双极闭锁均不会导致华东受端电网暂态电压失稳;锦屏-同里、锡盟-金坛、复龙-奉贤和溪洛渡-浙西特高压直流发生双极闭锁故障后,送端电网需采取切机措施才能保持系统稳定。%Based on the summer peak load operation mode of the planned "North China-Central China-East China" UHV power grid in 2015, there will be 10 HVDC transmission lines feeding into East China power grid. The strength of East China receiving-end power grid is analyzed by short circuit ratio (SCR) and multi-infeed short circuit ratio (MISCR), and the impacts of network topology adjustment in receiving-end power grid and the positions where the multi-infeed DC transmission lines are connected with East China receiving-end power grid on SCR/MISCR are dissected. By use of PSD-BPA transient stability program, transient voltage stability of East China receiving-end power grid under various faults is analyzed. Analysis results show that the positions, where the multi-infeed DC transmission lines are connected with East China receiving-end power grid, greatly impacts the strength of the latter; all unipolar block faults occurred in DC systems, single faults occurred in AC/DC system, three-phase permanent short-circuit fault, which causes the tripout of two circuits, occurred in UHVAC transmission line of receiving-end system and that

  15. 低压电力线载波信道测试装置设计%Design of a testing device for low voltage power line carrier communication channel

    Institute of Scientific and Technical Information of China (English)

    王立城; 胡科军; 霍超; 李建岐

    2015-01-01

    Power line carrier communication is widely used in automatic meter reading and street lamp control etc. However, the power line is not a dedicated communication channel, and influenced by the electrical equipment,power load,grid structure and other factors largely.The channel transmission characteristics vary in time domain and fre-quency domain, which directly influence the business carrying capacity and application effect of power communication products.This paper introduces a portable low voltage power line carrier communication channel testing device, which can realize the online measurement of noise, impedance and attenuation of the power line carrier channel, and can get the variation characteristics of carrier channel through the real-time analysis software.The device is of great signifi-cance to the technology realization and engineering application of power line communication products.%电力线载波通信在居民抄表、路灯控制等领域广泛应用,然而由于电力线不是专用信道,且受用电设备、电力负荷、线路结构等影响较大,其传输特性在时域、频域上具有多变性,直接影响到电力载波通信产品的业务承载能力和应用效果。文中研制了一种便携化低压电力线载波通信信道测试装置,实现了电力线载波信道的阻抗、衰减和噪声三个重要信道参量的在线测量,并可通过即时分析软件实时掌握载波信道的变化特征,对电力线通信产品的技术实现和工程化应用具有重要意义。

  16. Reducing the quantum-computing overhead with complex gate distillation

    Science.gov (United States)

    Duclos-Cianci, Guillaume; Poulin, David

    2015-04-01

    In leading fault-tolerant quantum-computing schemes, accurate transformations are obtained by a two-stage process. In a first stage, a discrete universal set of fault-tolerant operations is obtained by error-correcting noisy transformations and distilling resource states. In a second stage, arbitrary transformations are synthesized to desired accuracy by combining elements of this set into a circuit. Here we present a scheme that merges these two stages into a single one, directly distilling complex transformations. We find that our scheme can reduce the total overhead to realize certain gates by up to a few orders of magnitude. In contrast to other schemes, this efficient gate synthesis does not require computationally intensive compilation algorithms and a straightforward generalization of our scheme circumvents compilation and synthesis altogether.

  17. Phase Sensitive Cueing for 3D Objects in Overhead Images

    Energy Technology Data Exchange (ETDEWEB)

    Paglieroni, D W; Eppler, W G; Poland, D N

    2005-02-18

    A 3D solid model-aided object cueing method that matches phase angles of directional derivative vectors at image pixels to phase angles of vectors normal to projected model edges is described. It is intended for finding specific types of objects at arbitrary position and orientation in overhead images, independent of spatial resolution, obliqueness, acquisition conditions, and type of imaging sensor. It is shown that the phase similarity measure can be efficiently evaluated over all combinations of model position and orientation using the FFT. The highest degree of similarity over all model orientations is captured in a match surface of similarity values vs. model position. Unambiguous peaks in this surface are sorted in descending order of similarity value, and the small image thumbnails that contain them are presented to human analysts for inspection in sorted order.

  18. Counteracting Byzantine Adversaries with Network Coding: An Overhead Analysis

    CERN Document Server

    Kim, MinJi; Barros, Joao

    2008-01-01

    Network coding increases throughput and is robust against failures and erasures. However, since it allows mixing of information within the network, a single corrupted packet generated by a Byzantine attacker can easily contaminate the information to multiple destinations. In this paper, we study the transmission overhead associated with detecting Byzantine adversaries at a trusted node using network coding. We consider three different schemes: end-to-end error correction, packet-based Byzantine detection scheme, and generation-based Byzantine detection scheme. In end-to-end error correction, it is known that we can correct up to the min-cut between the source and destinations. However, if we use Byzantine detection schemes, we can detect polluted data, drop them, and therefore, only transmit valid data. For the dropped data, the destinations perform erasure correction, which is computationally lighter than error correction. We show that, with enough attackers present in the network, Byzantine detection scheme...

  19. Wearable IMU for Shoulder Injury Prevention in Overhead Sports

    Directory of Open Access Journals (Sweden)

    Samir A. Rawashdeh

    2016-11-01

    Full Text Available Body-worn inertial sensors have enabled motion capture outside of the laboratory setting. In this work, an inertial measurement unit was attached to the upper arm to track and discriminate between shoulder motion gestures in order to help prevent shoulder over-use injuries in athletics through real-time preventative feedback. We present a detection and classification approach that can be used to count the number of times certain motion gestures occur. The application presented involves tracking baseball throws and volleyball serves, which are common overhead movements that can lead to shoulder and elbow overuse injuries. Eleven subjects are recruited to collect training, testing, and randomized validation data, which include throws, serves, and seven other exercises that serve as a large null class of similar movements, which is analogous to a realistic usage scenario and requires a robust estimator.

  20. New composite fiber-optic overhead ground wire

    Science.gov (United States)

    Nishiyama, S.; Kitayama, Y.; Ona, A.; Shimada, S.; Kikuta, T.

    1986-11-01

    A composite fiber-optic overhead ground wire (OPGW) has already been used commercially. Most of the electric power companies have the plans to establish new telecommunication networks by means of OPGW, and it is greatly needed to develop OPGW which has a maximum number of fibers for specific ground wire size with low transmission loss, easy handling and higher reliability. We have developed New OPGW, which satisfies these demands. It has the following features: (1) 18 fibers within 75 sq mm ground wire. (2) The fiber is a pure silica core and a fluorine-doped cladding single mode fiber with the average transmission loss of 0.4 dB/km at 1.3 micron. (3) Six fibers are stranded into a compact bunch and three bunches are housed in the spiral grooves of an aluminum spacer.

  1. 75 FR 75 - Special Conditions: Boeing Model 787-8 Airplane; Overhead Crew Rest Compartment

    Science.gov (United States)

    2010-01-04

    ... Model 787-8 Airplane; Overhead Crew Rest Compartment AGENCY: Federal Aviation Administration (FAA), DOT... installation of an overhead crew rest compartment. The applicable airworthiness regulations do not contain... Design Features Crew rest compartments have been installed and certificated on several Boeing...

  2. 31 CFR Appendix I(f) to Part 13 - Estimated Overhead and Administrative Costs

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Estimated Overhead and Administrative Costs I(F) Appendix I(F) to Part 13 Money and Finance: Treasury Office of the Secretary of the Treasury... Pt. 13, App. I(F) Appendix I(F) to Part 13—Estimated Overhead and Administrative Costs Date:...

  3. Efficient datapath merging for the overhead reduction of run-time reconfigurable systems

    NARCIS (Netherlands)

    Fazlali, M.; Zakerolhosseini, A.; Gaydadjiev, G.

    2010-01-01

    High latencies in FPGA reconfiguration are known as a major overhead in run-time reconfigurable systems. This overhead can be reduced by merging multiple data flow graphs representing different kernels of the original program into a single (merged) datapath that will be configured less often

  4. Efficient datapath merging for the overhead reduction of run-time reconfigurable systems

    NARCIS (Netherlands)

    Fazlali, M.; Zakerolhosseini, A.; Gaydadjiev, G.

    2010-01-01

    High latencies in FPGA reconfiguration are known as a major overhead in run-time reconfigurable systems. This overhead can be reduced by merging multiple data flow graphs representing different kernels of the original program into a single (merged) datapath that will be configured less often compare

  5. Performance analysis of surge arrester on high voltage systems using ATP

    Energy Technology Data Exchange (ETDEWEB)

    Nallagownden, P.; Magumane, A.H. [Univ. Teknologi Petronas, Perak (Malaysia); Kanth, K.S.R. [Tenaga National Berhad (Malaysia)

    2008-07-01

    Lightning strikes are among the major factors that cause failures in electrical power systems. Phase to ground arresters are commonly installed at power transformer terminals to offer some lightning protection. However, it is important to understand the performance of metal oxide arresters under very fast transient overvoltages in order to determine the protection zone of the arrester and to achieve economical benefits. This study investigated lightning overvoltage protection in a complete three-phase scheme of a 500 KV substation. Overvoltages originated from direct lightning stroke on a phase of a real overhead line (OHL) model. The effect of the separation distance of the arrester from the transformer connected at the open end of the substations was investigated as well as the performance of the arrester for different substation configurations. In the first scenario, the connection of the arrester and transformer was done with a direct connection of an overhead line. In the second scenario, the connection of these devices was done through a cable. Both the overhead line and cable lengths were varied and the maximum overvoltages coming to the transformer were recorded. The results showed that there is a direct proportionality between overvoltages and length of the overhead line or cable. As long the length of the line or cable between the arrester and the transformer was increased, the vulnerability of the transformer to receive high overvoltages also increased. Surge overvoltages were found to be very sensitive to impedance of the line or cable. The direct connections of overhead lines between the arrester and transformer make it necessary to add some protective device. It was suggested that surge arresters should be installed every 200 meters along the overhead lines in order to ensure the safety of equipment. 12 refs., 4 tabs., 8 figs.

  6. Induced voltage in an open wire

    CERN Document Server

    Morawetz, K; Trupp, A

    2015-01-01

    A puzzle arising from Faraday's law is considered and solved concerning the question which voltage is induced in an open wire feeling a time-varying homogeneous magnetic field. The longitudinal electric field contributes 1/3 and the transverse field 2/3 to the induced voltage. The representation of a homogeneous and time-varying magnetic field implies unavoidably a certain symmetry point or line dependent on the geometry of the source. As a consequence the induced voltage of an open wire is found to be the area covered with respect to the symmetry line or point perpendicular to the magnetic field. This in turn allows to find the symmetry points of a magnetic field source by measuring the voltage of an open wire. We present two exactly solvable models for a symmetry point and for a symmetry line. The results are applicable to open circuit problems and for astrophysical applications.

  7. 高压输配电线路在线监测设备供电电源的研究%Research on power supply of online monitoring equipment for high-voltage transmission and distribution line

    Institute of Scientific and Technical Information of China (English)

    谢志远; 毕亭亭; 金慧莹; 李亚康

    2016-01-01

    A new design scheme of power supply is proposed to solve the problems existing in current power supply of online monitoring equipment for high voltage transmission and distribution lines .We adopt two cores of different mate-rials in parallel, and choose appropriate core to work according to the scope of current and combine the induction pow -er supply with the lithium battery power supply .By comparing properties of different core materials , the nanocrystal-line alloy and silicon steel are selected , and the power supply circuit is designed .Experimental results show that the power supply can provide sable power between zero to one thousand amperes and have no power dead -band.%针对目前高压输配电线路在线监测设备供电电源的缺点,提出了一种新型供电电源设计方案.采用两个不同材质的取能磁芯并行工作,根据电流范围选择合适的磁芯进行取能,同时将感应取能供电与锂电池供电相结合.通过对比不同磁芯材料的特性,选定了铁基纳米晶合金与硅钢片制作磁芯,并设计了电源电路.实验测试结果表明:该供电电源可在电流为0 A~1000 A范围内稳定供电,无电源死区.

  8. AODV routing overhead analysis based on link failure probability in MANET

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qin-juan; WU Mu-qing; ZHEN Yan; SHANG Cui-li

    2010-01-01

    This article puts forward an Ad-hoc on-demand distance vector routing(AODV)routing overhead analysis method in mobile Ad-hoc network(MANET).Although multiple routing protocols have been proposed to improve the performance,scarcely any paper analyzed the routing overhead caused by routing setup and maintenance processes in mathematical way.Routing overhead consumes part of network resources and limits the supported traffic in the network.For on-demand routing protocols like AODV,the routing overhead depends on the link failure probability to a great extent.This article analyzes the collision probability caused by hidden-node problem and the impact on link failure probability.In chain and rectangle scenarios,it presents a mathematical analysis of the theoretical routing overhead of AODV protocol based on link failure probability.Simulations on OPNET 14.5platform match well with the theoretical derivation which confirms the effectiveness of the analysis method.

  9. Fundamentals of Inter-cell Overhead Signaling in Heterogeneous Cellular Networks

    CERN Document Server

    Xia, Ping; Andrews, Jeffrey G

    2011-01-01

    Heterogeneous base stations (e.g. picocells, microcells, femtocells and distributed antennas) will become increasingly essential for cellular network capacity and coverage. Up until now, little basic research has been done on the fundamentals of managing so much infrastructure -- much of it unplanned -- together with the carefully planned macro-cellular network. Inter-cell coordination is in principle an effective way of ensuring different infrastructure components behave in a way that increases, rather than decreases, the key quality of service (QoS) metrics. The success of such coordination depends heavily on how the overhead is shared, and the rate and delay of the overhead sharing. We develop a novel framework to quantify overhead signaling for inter-cell coordination, which is usually ignored in traditional 1-tier networks, and assumes even more importance in multi-tier heterogeneous cellular networks (HCNs). We derive the overhead quality contour for general K-tier HCNs -- the achievable set of overhead...

  10. Varying Overhead Ad Hoc on Demand Vector Routing in Highly Mobile Ad Hoc Network

    Directory of Open Access Journals (Sweden)

    V. Balaji

    2011-01-01

    Full Text Available Problem statement: An inherent feature of mobile ad hoc networks is the frequent change of network topology leading to stability and reliability problems of the network. Highly dynamic and dense network have to maintain acceptable level of service to data packets and limit the network control overheads. This capability is closely related as how quickly the network protocol control overhead is managed as a function of increased link changes. Dynamically limiting the routing control overheads based on the network topology improves the throughput of the network. Approach: In this study we propose Varying Overhead - Ad hoc on Demand Vector routing protocol (VO-AODV for highly dynamic mobile Ad hoc network. The VO-AODV routing protocol proposed dynamically modifies the active route time based on the network topology. Results and Conclusion: Simulation results prove that the proposed model decreases the control overheads without decreasing the QOS of the network.

  11. Special insulator for installation of optical phase conductor on 15 kV line

    Energy Technology Data Exchange (ETDEWEB)

    Argasinska, H. [Energoprojekt-Warszawa, Warsaw (Poland); Fleszynski, J.; Sojda, E.; Tyman, A. [Wroclaw Univ. (Poland)

    1997-12-31

    The use of optical fibres for the transmission of information over high-voltage lines was discussed. Three designs of fibre optic cables that can be run on HV lines: (1) optical ground wire (OPGW) cables run within ground wires, (2) all dielectric self-supporting (ADSS) cables suspended from overhead transmission line, and (3) Fibwrap (Skywrap) cables wrapped around the ground wire and which, in some cases, run on the phase conductors. To date, the market has been dominated by OPGW. Transmission of information by fibre optic cable requires a special insulator-separator. Tests were conducted on insulator-separators made of polycarbonate, silicon rubber-thermosetting, silicon rubber-RTV and polymer concrete to check their compliance with the high voltage requirements for pollution zone 3. Not all the materials met the requirements for this zone. A Polish-made insulator made of silicon rubber RTV and which met the requirements for pollution zone 3, was installed on a 15 kV power line. 5 refs., 1 tab., 4 figs.

  12. Evaluation of the cytotoxic effects of PLGA coated iron oxide nanoparticles as a carrier of 5- fluorouracil and mega-voltage X-ray radiation in DU145 prostate cancer cell line.

    Science.gov (United States)

    Hajikarimi, Zahra; Khoei, Samideh; Khoee, Sepideh; Mahdavi, Seied Rabi

    2014-12-01

    The purpose of this study was to investigate the uptake and cytotoxic effects of magnetic poly lactic-co-glycolic acid (PLGA)-coated iron oxide nanoparticles as a carrier of 5-fluorouracil (5-FU) and X-ray on the level of proliferation capacity of DU145 prostate carcinoma cell line in monolayer culture. Following monolayer culture, DU 145 cells were treated with different concentrations of 5-FU or 5-FU loaded nanoparticles for 24 h and 2Gy X-ray (6 Mega-voltage (MV)). The rate of nanoparticles penetration was then measured using atomic adsorption spectroscopy (AAS). The cytotoxicity effect of these nanoparticles with/ without X-ray radiation was evaluated using colony formation assay. Spectroscopy results showed that iron content and therefore the cellular uptake of 5-FU loaded nanoparticles increased with increasing nanoparticle concentrations. Further, the proliferation capacity of the cells decreased with the increase of 5-FU and 5- FU loaded nanoparticle concentrations in combination with X-ray radiation. However the extent of reduction in colony number following treatment with 5-FU-loaded nanoparticles in combination with 2Gy of megavoltage X-ray radiation was significantly more than for free 5-FU. Thus, drug-loaded nanoparticles could deliver 5-FU more efficiently into the cells. PLGA coated iron oxide nanoparticles are therefore effective drug delivery vehicles for 5-FU. PLGA coated iron oxide nanoparticles are biocompatible and this coating is an appropriate surface that can penetrate into the cells.

  13. 跨越式高压输电线路巡线机器人动力学研究%Leaping high-voltage transmission line inspection robot dynamics study

    Institute of Scientific and Technical Information of China (English)

    王婷; 吴功平

    2015-01-01

    The structure character of leaping high voltage transmission line inspection robot is analysed and inspection robot spatial coordinates is built with the DH method, and then the dynamic model of the robot manipulator is establishedon the basis of Lagrange principle.The dynamics simulation and experiment study of one type posture of the manipulatorjoints are accomplished, the force or torque of joints is confirmed after presetting displacement curve and speed curve and theoretical foundation is prepared for the real-time control of robot.%分析了跨越式高压输电线路巡线作业机器人的结构特征,采用D-H法构建巡线机器人空间坐标,用Lagrange方法建立了机器人机械臂的动力学模型。基于此动力学模型,对一种典型工况进行了机械臂各关节动力学逆问题仿真,通过给定已知运动轨迹对应的各关节位移、速度曲线,确定所需的关节力矩或关节力,为机器人的实时控制提供理论依据。

  14. Transient Voltage Recorder

    Science.gov (United States)

    Medelius, Pedro J. (Inventor); Simpson, Howard J. (Inventor)

    2002-01-01

    A voltage transient recorder can detect lightning induced transient voltages. The recorder detects a lightning induced transient voltage and adjusts input amplifiers to accurately record transient voltage magnitudes. The recorder stores voltage data from numerous monitored channels, or devices. The data is time stamped and can be output in real time, or stored for later retrieval. The transient recorder, in one embodiment, includes an analog-to-digital converter and a voltage threshold detector. When an input voltage exceeds a pre-determined voltage threshold, the recorder stores the incoming voltage magnitude and time of arrival. The recorder also determines if its input amplifier circuits clip the incoming signal or if the incoming signal is too low. If the input data is clipped or too low, the recorder adjusts the gain of the amplifier circuits to accurately acquire subsequent components of the lightning induced transients.

  15. High Voltage Power Transmission for Wind Energy

    Science.gov (United States)

    Kim, Young il

    The high wind speeds and wide available area at sea have recently increased the interests on offshore wind farms in the U.S.A. As offshore wind farms become larger and are placed further from the shore, the power transmission to the onshore grid becomes a key feature. Power transmission of the offshore wind farm, in which good wind conditions and a larger installation area than an onshore site are available, requires the use of submarine cable systems. Therefore, an underground power cable system requires unique design and installation challenges not found in the overhead power cable environment. This paper presents analysis about the benefit and drawbacks of three different transmission solutions: HVAC, LCC/VSC HVDC in the grid connecting offshore wind farms and also analyzed the electrical characteristics of underground cables. In particular, loss of HV (High Voltage) subsea power of the transmission cables was evaluated by the Brakelmann's theory, taking into account the distributions of current and temperature.

  16. Energy Storage Options for Voltage Support in Low-Voltage Grids with High Penetration of Photovoltaic

    DEFF Research Database (Denmark)

    Marra, Francesco; Tarek Fawzy, Y.; Bülo, Thorsten

    2012-01-01

    The generation of power by photovoltaic (PV) systems is constantly increasing in low-voltage (LV) distribution grids, in line with the European environmental targets. To cope with the effects on grid voltage profiles during high generation and low demand periods, new solutions need to be establis...

  17. Application of Geographic Information System for the Installation of Surge Arrestors on over head 132 k-v Power Line

    Directory of Open Access Journals (Sweden)

    Kamran Hafeez

    2012-01-01

    Full Text Available Power system consists of generation, transmission and distribution of electrical energy. Transmission lines transport the desired amount of electrical power from one place to another. The Protection of Power line is a very important factor in smooth transfer of electric power. Lightning is a major cause of overhead line faults.It is necessary to protect the power apparatus from over volts in electric system, namely lighting over voltages & switching over voltages. The objectives of this study is to protect the power system equipment's from lightning using geographic information system approach A Geographical Information System (GIS is a collection of software's that allows you to create, visualize, query and analyse geographic data.This paper presents the idea of installing line surge arrestors by marking the exact location of towers using a multispectral satellite image and image processing software with the help of gps points taken on the ground. A case study of 132 k-v existing double circuit line from Sheik Muhammadi 500 k-v grid to 132 k-v city grid Peshawar is considered for results where as input data to GIS is in the form of spot-5 satellite image having 2.5m resolution.

  18. Reducing the overheads of hardware acceleration through datapath integration

    Science.gov (United States)

    Jääskeläinen, Pekka; Kultala, Heikki; Pitkänen, Teemu; Takala, Jarmo

    2008-02-01

    Hardware accelerators are used to speed up execution of specific tasks such as video coding. Often the purpose of hardware acceleration is to be able to use a cheaper or, for example, more energy economical processor for executing the majority of the application in software. However, when using hardware acceleration, new overheads are produced mainly due to the need to transfer data to and from the accelerator and signaling the readiness of the accelerator computation to the processor. We find the traditional mechanisms suboptimal for fine-grain hardware acceleration, especially when energy efficiency is important. This paper explores a technique unique to Transport Triggered Architectures to interface with hardware accelerators. The proposed technique places hardware accelerators to the processor data path, making them visible as regular function units to the programmer. This way communication costs are reduced as data can be transferred directly to the accelerator from other processor data path components and synchronization can be done by polling a simple ready flag in the accelerator function unit. Additionally, this setup enables the instruction scheduler of the compiler to schedule the hardware accelerator like any other operation, thus partially hide its latency with other program operations. The paper presents a case study with an audio decoder application in which fine-grain and coarse-grain hardware accelerators are integrated to the processor data path as function units. The case is used to study several different synchronization, communication, and latency-hiding techniques enabled by this kind of setup.

  19. Automatic voltage imbalance detector

    Science.gov (United States)

    Bobbett, Ronald E.; McCormick, J. Byron; Kerwin, William J.

    1984-01-01

    A device for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.

  20. 带弧垂特高压交流输电线路的电磁剂量学分析%Analysis of electromagnetic dosimetry by ultra high voltage AC transmission line with belt sag

    Institute of Scientific and Technical Information of China (English)

    张利航; 逯迈; 陈小强; 侯立伟

    2016-01-01

    采用Comsol仿真软件和人体模型计算分析倒三角较贴近实际的带弧垂特高压交流输电线路对人体产生的电场效应,并与理想直导线的结果进行对比。结果表明,人体以及人体附近电场和感应电流分布不均匀,体外电场最大值集中于人体头部表面上方,关节连接处和端部的电场、感应电流密度较大。带弧垂特高压输电线路在人体各组织产生的电场和感应电流密度均较理想笔直导线线路下高约17%~19%;与国际非电离辐射防护委员会(International commission on non-ionizing radiation protection, ICNIRP)导则限值相比较,电场强度无论是对专业人员还是普通民众均在 ICNIRP 导则限值范围内;而感应电流密度除人体腿部下部、头皮与颈部连接处附近的略高于ICNIRP导则中普通民众的限值外,其他均在ICNIRP导则限值范围内。两种类型特高压输电线路所产生的电磁辐射对专业人员是安全的,对普通民众应注意适当的防护。%The aim is to investigate the electric field effect produced by the ultra high voltage (UHV) AC transmission lines with belt sag on the human body. A simulation software named Comsol and a human body model were used to calculate and analyze the electric field effect caused by the nabla UHV AC transmission lines closely to the reality, and then the result was compared with the one produced by ideal straight lines. The results indicated that in the human and the near-field region, the distribution of electric field and induced current was nonuniform. The maximum electric field focused on the above region of human head surface. The value of electric field intensity and  induced current density in the joints of the body were high. Below the actual and ideal straight UHV transmission lines, the electric field intensity and induced current density produced by the belt sag wire in all tissues including central nervous system of human was 17

  1. Mixed voltage VLSI design

    Science.gov (United States)

    Panwar, Ramesh; Rennels, David; Alkalaj, Leon

    1993-01-01

    A technique for minimizing the power dissipated in a Very Large Scale Integration (VLSI) chip by lowering the operating voltage without any significant penalty in the chip throughput even though low voltage operation results in slower circuits. Since the overall throughput of a VLSI chip depends on the speed of the critical path(s) in the chip, it may be possible to sustain the throughput rates attained at higher voltages by operating the circuits in the critical path(s) with a high voltage while operating the other circuits with a lower voltage to minimize the power dissipation. The interface between the gates which operate at different voltages is crucial for low power dissipation since the interface may possibly have high static current dissipation thus negating the gains of the low voltage operation. The design of a voltage level translator which does the interface between the low voltage and high voltage circuits without any significant static dissipation is presented. Then, the results of the mixed voltage design using a greedy algorithm on three chips for various operating voltages are presented.

  2. 电力变压器离线局部放电测量试验中的容升现象分析%Analysis of capacitive voltage rise during off-line partial discharge tests on power transformers

    Institute of Scientific and Technical Information of China (English)

    王烜; 曹晓珑; 李云阁; 刘英

    2007-01-01

    Partial discharge test on a transformer is carried out according to the items in IEC 60. During the test, unproved measuring system is calibrated by proved system at a voltage no less than 50% the rated testing voltage. The result is then extrapolated linearly, leading to an error related to the distribution of stray capacitance, which varies with the testing frequency, especially to large transformers. In this paper a factor, named the capacitive rise fact, is introduced to assess the rise. The factor can be adjusted to some extent by changing the reactance that is connected to the LV side of the testing circuit to lower the capacity of the power source. However, the factor changes when the voltage divider on the high voltage side is removed after the voltage ratio has been calculated, and a great error is resulted under unfavorable conditions.

  3. A low voltage CMOS low drop-out voltage regulator

    Science.gov (United States)

    Bakr, Salma Ali; Abbasi, Tanvir Ahmad; Abbasi, Mohammas Suhaib; Aldessouky, Mohamed Samir; Abbasi, Mohammad Usaid

    2009-05-01

    A low voltage implementation of a CMOS Low Drop-Out voltage regulator (LDO) is presented. The requirement of low voltage devices is crucial for portable devices that require extensive computations in a low power environment. The LDO is implemented in 90nm generic CMOS technology. It generates a fixed 0.8V from a 2.5V supply which on discharging goes to 1V. The buffer stage used is unity gain configured unbuffered OpAmp with rail-to-rail swing input stage. The simulation result shows that the implemented circuit provides load regulation of 0.004%/mA and line regulation of -11.09mV/V. The LDO provides full load transient response with a settling time of 5.2μs. Further, the dropout voltage is 200mV and the quiescent current through the pass transistor (Iload=0) is 20μA. The total power consumption of this LDO (excluding bandgap reference) is only 80μW.

  4. Calculation and Analysis on Steady-State Induced Voltage During Maintenance Operation of Multi Parallel Circuits of EHV/UHVDC/UHVAC Transmission Lines%并行多回交直流输电线路检修作业时稳态感应电压计算与分析

    Institute of Scientific and Technical Information of China (English)

    张文杰; 张弓达; 岳灵平; 张瑞; 楼平; 周沛洪; 张晓琴

    2014-01-01

    Erecting multi circuits of AC and DC transmission lines in the same corridor can save the land resources, however there are electrostatic and electromagnetic couplings among multi circuits of AC and DC transmission lines. It is favorable for the safety of maintenance operation of these transmission lines to research the steady-state induction voltage of transmission lines parallelly erected in the corridor. Through the calculation by electromagnetic transient program (EMTP), a computation model of six UHVAC and EHVDC/UHVDC transmission lines parallelly erected in the corridor located in Huzhou, Zhejiang province is established;the influence due to the coupling between UHVAC lines and EHVDC/UHVDC lines are calculated; the amplitudes and distributions of electrostatic induction voltages and electromagnetic induction voltages during the live-line overhaul and power-off maintenance under the combination of different operating modes of UHVAC and EHVDC/UHVDC lines are analyzed. Analysis results show that the influence of the steady-state induction voltage among parallelly erected multi circuits of AC and DC transmission line on the live-line overhaul and power-off maintenance modes and tools specified in current operating instruction can be neglected.%同走廊架设多回交直流输电线路可节约土地资源,但多回交直流输电线路相互之间存在静电和电磁耦合。研究并行走廊内各回线路稳态感应有利于线路检修作业安全。通过电磁暂态计算程序建立湖州多回并行走廊内的6条超、特高压交直流输电线路计算模型,计算了特高压交流线路与超、特高压直流线路之间的耦合影响,分析了带电和停电检修作业时在交直流线路不同运行方式组合下各检修线路静电和电磁感应电压的幅值和分布。结果表明,湖州地区并行多回交直流线路之间稳态感应电压对目前规程规定的带电和停电检修作业方式和工具的影响可以不予考虑。

  5. A Wiring-Aware Approach to Minimizing Built-In Self-Test Overhead

    Institute of Scientific and Technical Information of China (English)

    Abdil Rashid Mohamed; Zebo Peng; Petru Eles

    2005-01-01

    This paper describes a built-in self-test (BIST) hardware overhead minimization technique used during a BIST synthesis process. The technique inserts a minimal amount of BIST resources into a digital system to make it fully testable.The BIST resource insertion is guided by the results of symbolic testability analysis. It takes into consideration both BIST register cost and wiring overhead in order to obtain the minimal area designs. A Simulated Annealing algorithm is used to solve the overhead minimization problem. Experiments show that considering wiring area during BIST synthesis results in smaller final designs as compared to the cases when the wiring impact is ignored.

  6. ANALISIS PEMBEBANAN BIAYA OVERHEAD PABRIK TERHADAP HARGA JUAL PRODUK PADA UKM DI WILAYAH SUKABUMI

    Directory of Open Access Journals (Sweden)

    Yuri Rahayu

    2016-03-01

    Full Text Available Abstract - Knowledge of the classification of costs on the perpetrators of Small and Medium Enterprises (SMEs is very minimal, they average only know and understand that the elements of the cost of production only raw material costs and labor costs alone, even if such costs exist, they regard it as another charge Other, when it goes into the category of Factory Overhead so they are often mistakenly treated and taken of the Factory Overhead. The aim of this study was to menganalsisi and provide an overview and input on what and how to treat seharusnnya Factory Overhead against Selling price of the product. Quantitative research methods with the Technical Descriptive analysis of the population is a sub-sector of Small and Medium Enterprises (SMEs located in the city of Sukabumi. Sample used by purposive sampling. The conclusion from this study showed that the need for step-by-step in the determination of loading Factory Overhead ranging from understanding the categories included in the Factory Overhead Costs, Making Budget, Select base load, so that the company knows how Overhead factory that has been absorbed by the unit of product that produced that effect to the determination of Product Sales Price is Right so the survival of the company could be maintained. Keywords: BOP, SMEs, Caculation, Treatment Abstraksi - Pengetahuan akan penggolongan biaya pada pelaku Usaha Kecil dan Menengah (UKM memang sangat minim, mereka rata-rata hanya mengetahui dan paham bahwa unsur dari biaya produksi hanya Biaya bahan baku dan biaya tenaga kerja saja, sekalipun biaya tersebut ada, mereka menganggapnya sebagai biaya lain-lain, padahal itu   masuk ke dalam katagori Biaya Overhead Pabrik sehingga mereka sering keliru memperlakukan dan memperhitungan Biaya Overhead Pabrik tersebut. Tujuan dari penelitian ini untuk menganalsisi dan memberikan gambaran dan masukan tentang apa dan bagaimana seharusnnya memperlakukan Biaya Overhead Pabrik terhadap harga Jual produk

  7. Improving the Performance of CPU Architectures by Reducing the Operating System Overhead (Extended Version

    Directory of Open Access Journals (Sweden)

    Zagan Ionel

    2016-07-01

    Full Text Available The predictable CPU architectures that run hard real-time tasks must be executed with isolation in order to provide a timing-analyzable execution for real-time systems. The major problems for real-time operating systems are determined by an excessive jitter, introduced mainly through task switching. This can alter deadline requirements, and, consequently, the predictability of hard real-time tasks. New requirements also arise for a real-time operating system used in mixed-criticality systems, when the executions of hard real-time applications require timing predictability. The present article discusses several solutions to improve the performance of CPU architectures and eventually overcome the Operating Systems overhead inconveniences. This paper focuses on the innovative CPU implementation named nMPRA-MT, designed for small real-time applications. This implementation uses the replication and remapping techniques for the program counter, general purpose registers and pipeline registers, enabling multiple threads to share a single pipeline assembly line. In order to increase predictability, the proposed architecture partially removes the hazard situation at the expense of larger execution latency per one instruction.

  8. Combined Digital Electronic Current and Voltage Transducer

    Institute of Scientific and Technical Information of China (English)

    段雄英; 邹积岩; 等

    2002-01-01

    A high-performance current and voltage measurement system has been developed in power system.The system is composed of two parts:one current measurement element and one voltage measurement element.A Rogowski coil and a capacitive voltage divider are used respectively for the line current and voltage measurements.Active electronic components are used to modulate signal,and power supply for these components is drawn from power line via an auxiliary current transformer,Measurement signal is transmitted y optical fibers,which is resistant to electromagnetic induction and noise,With careful design and the use of digital signal processing technology,the whole system can meet 0.5% accuracy for metering and provides large dynamic range coupled with good accuracy for protective relaying use.

  9. 高压输电线路除冰机器人机械本体结构的研究%Mechanical Structure Research of Deicing Robot for High Voltage Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    曹雷; 郭锐; 张峰

    2013-01-01

    北方输电线路冬季因受冰雪危害引起的供电中断事故严重,修复工作难度大、周期长、停电面积广,是全世界范围内需解决的难点问题.针对高压输电线路覆冰情况,提出了一种线路除冰机器人,由移动机构、除冰刀具、电源系统和控制系统组成,机器人利用固定在前端的三角形刀具的撞击力清除覆冰;驱动轮采用V型结构.适应一定范围的线径,采用的锁紧机构和防倾倒机构,为机器人提供了足够的稳定支撑,有效防止了机器人激烈碰撞时向后倾斜.该机器人体较小、除冰效率高,可清除厚度20mm的覆冰.%Transmission lines of power in northern region are being harmed because of overloading snows and ice during winter. This kind of accident often can cause large-areas blackout for days and masses of complicated repair as well, which has come into notice not only in china but all around the world. According to the icing condition of high voltage transmission lines, a kind of deicing robot is proposed. By moving mechanism, deicing tool, power system and control system, this robot uses the impact force of the triangular tools which are fixed in front of the robot. Using V type structure of driving wheel can adapt to a range of wire diameter. The locking mechanism and the dumping mechanism can provide sufficient stability support and effectively prevent robot tilted backwards. The robot has the advantages of light weight,small size and high deicing efficiency and can remove the20mm thickness of ice.

  10. Headgear Accessories Classification Using an Overhead Depth Sensor

    Science.gov (United States)

    Luna, Carlos A.; Marron-Romera, Marta; Mazo, Manuel; Luengo-Sanchez, Sara; Macho-Pedroso, Roberto

    2017-01-01

    In this paper, we address the generation of semantic labels describing the headgear accessories carried out by people in a scene under surveillance, only using depth information obtained from a Time-of-Flight (ToF) camera placed in an overhead position. We propose a new method for headgear accessories classification based on the design of a robust processing strategy that includes the estimation of a meaningful feature vector that provides the relevant information about the people’s head and shoulder areas. This paper includes a detailed description of the proposed algorithmic approach, and the results obtained in tests with persons with and without headgear accessories, and with different types of hats and caps. In order to evaluate the proposal, a wide experimental validation has been carried out on a fully labeled database (that has been made available to the scientific community), including a broad variety of people and headgear accessories. For the validation, three different levels of detail have been defined, considering a different number of classes: the first level only includes two classes (hat/cap, and no hat/cap), the second one considers three classes (hat, cap and no hat/cap), and the last one includes the full class set with the five classes (no hat/cap, cap, small size hat, medium size hat, and large size hat). The achieved performance is satisfactory in every case: the average classification rates for the first level reaches 95.25%, for the second one is 92.34%, and for the full class set equals 84.60%. In addition, the online stage processing time is 5.75 ms per frame in a standard PC, thus allowing for real-time operation. PMID:28796177

  11. a Distance Protection Strategic Spare Relay for 132/66 kv Overhead Lines

    Science.gov (United States)

    Harris, R. T.; Roberts, A. G.; Marks, A.; Phipps, W.

    2010-06-01

    The South African electrical supply utility (Eskom) has been experiencing problems in the field of protection, maintenance and in-service breakdowns which influence the quality of electrical supply to the consumer, an important and integral component of the utility business. As a result, further development of the generic relay, implemented as a strategic spare relay for the replacement of several schemes operating within Eskom's southern region has been initiated. These include the electromechanical, solid state and numerical distance protection relays and scheme failures on the 132/66 kV feeder network. The research considers the development, testing and configuration of the strategic spare relay in terms of software and peripheral hardware for the input and output terminal connections, generic equations and settings, for the purpose of scheme replacements. The various schemes are assessed for stepped distance and permissive intertripping for three and single pole operation. This is done in conjunction with the internal and external circuit diagrams to understand the detailed operation of the scheme and to ensure the effective implementation of the strategic spare relay. The generic relay is configured for the emergency replacement of the various schemes during in-service breakdowns. This constitutes a temporary installation and therefore the downtime of all the distance protection schemes that require replacement, is limited to a minimum.

  12. Dynamic Analysis of Overhead Power Lines after Ice-Shedding Using Finite Element Method

    Science.gov (United States)

    Murín, Justín; Hrabovský, Juraj; Gogola, Roman; Janíček, František

    2016-12-01

    In this paper, the analysis of ice-shedding from ACSR conductors to its swing up height and vibration using Finite Element Method (FEM) is presented. For the numerical simulations the effective material properties of the ACSR conductor are calculated using the homogenisation method. Numerical analysis concerning vibration of one and triple-bundle conductors with icing for a whole range or on their certain parts are performed. The impact of ice-shedding to the mechanical tension in the conductors at the points of attachment is investigated and evaluated. Identification of the impact of ice-shedding from the ACSR conductors on its mechanical state may contribute to increasing the safety and quality of an electrical transmission system.

  13. High voltage electricity installations a planning perspective

    CERN Document Server

    Jay, Stephen Andrew

    2006-01-01

    The presence of high voltage power lines has provoked widespread concern for many years. High Voltage Electricity Installations presents an in-depth study of policy surrounding the planning of high voltage installations, discussing the manner in which they are percieved by the public, and the associated environmental issues. An analysis of these concerns, along with the geographical, environmental and political influences that shape their expression, is presented. Investigates local planning policy in an area of the energy sector that is of highly topical environmental and public concern Cover

  14. A Revive on 32×32 Bit Multiprecision Dynamic Voltage Scaling Multiplier with Operands Scheduler

    Directory of Open Access Journals (Sweden)

    Mrs.S.N.Rawat

    2016-02-01

    Full Text Available In this paper, we present a Multiprecision (MP reconfigurable multiplier that incorporates variable precision, parallel processing (PP, razor-based dynamic voltage scaling (DVS, and dedicated MP operands scheduling to provide optimum performance for a variety of operating conditions. All of the building blocks of the proposed reconfigurable multiplier can either work as independent smaller-precision multipliers or work in parallel to perform higher-precision multiplications. Given the user’s requirements (e.g., throughput, a dynamic voltage/ frequency scaling management unit configures the multiplier to operate at the proper precision and frequency. Adapting to the run-time workload of the targeted application, razor flip-flops together with a dithering voltage unit then configure the multiplier to achieve the lowest power consumption. The single-switch dithering voltage unit and razor flip-flops help to reduce the voltage safety margins and overhead typically associated to DVS to the lowest level. The large silicon area and power overhead typically associated to reconfigurability features are removed. Finally, the proposed novel MP multiplier can further benefit from an operands scheduler that rearranges the input data, hence to determine the optimum voltage and frequency operating conditions for minimum power consumption. This low-power MP multiplier is fabricated in AMIS 0.35-μm technology. Experimental results show that the proposed MP design features a 28.2% and 15.8% reduction in circuit area and power consumption compared with conventional fixed-width multiplier. When combining this MP design with error-tolerant razor-based DVS, PP, and the proposed novel operands scheduler, 77.7%–86.3% total power reduction is achieved with a total silicon area overhead as low as 11.1%. This paper successfully demonstrates that a MP architecture can allow more aggressive frequency/supply voltage scaling for improved power efficiency

  15. Anterior internal impingement of the shoulder in rugby players and other overhead athletes

    Directory of Open Access Journals (Sweden)

    Siddharth R. Shah, MBBS, MSc Sports Medicine (UK, MRCS-Ed

    2017-04-01

    Conclusion: This series of anterior internal impingement, which we believe is the largest in the literature to date, demonstrates the value of an to assess and successfully treat overhead athletes with anterior impingement syndrome.

  16. Isokinetic Scapular Muscle Performance in Overhead Athletes With and Without Impingement Symptoms

    OpenAIRE

    Ann M. Cools; Witvrouw, Erik E.; Mahieu, Nele N; Danneels, Lieven A

    2005-01-01

    Context: Overhead activities such as throwing, tennis, or volleyball place athletes at considerable risk for overuse injuries. A relationship between scapulothoracic muscle imbalance and shoulder pain has been suggested.

  17. Effects of overhead work configuration on muscle activity during a simulated drilling task.

    Science.gov (United States)

    Maciukiewicz, Jacquelyn M; Cudlip, Alan C; Chopp-Hurley, Jaclyn N; Dickerson, Clark R

    2016-03-01

    Overhead work is a known catalyst for occupational shoulder injury. Industrial workers must often adopt awkward overhead postures and loading profiles to complete required tasks, potentially elevating injury risk. This research examined the combined influence of multiple overhead working parameters on upper extremity muscular demands for an industrial drilling application. Twenty-two right-handed males completed 24 unilateral and bilateral overhead work exertions stratified by direction (upward, forward), point of force application (15, 30 and 45 cm in front of the body), and whole-body posture (seated, standing). The dependency of electromyographic (EMG) activity on several factors was established. Significant two-way interactions existed between point of force application and direction (p heights are not ideal, and should be avoided, and where this is not possible reaches should be reduced.

  18. Software in the DOE: The Hidden Overhead of''The Build''

    Energy Technology Data Exchange (ETDEWEB)

    Kumfert, G; Epperly, T

    2002-02-28

    ''The Build'' is the infrastructure needed to convert software from source code to usable form. It is intimately tied to the software it supports, knowing about every file and automating every transformation needed to produce a working program. Every developer knows that a project spends some labor overhead on ''the build.'' How big is this hidden overhead? According to 34 scientific software developers we surveyed at Lawrence Livermore National Labs, among colleagues at other DOE labs, and a handful of academics the ''perceived'' overhead averages around 12%. Individual cases of 20% to 30% were not uncommon. In one project claiming a 20% overhead, we found supporting evidence by combing through their CVS repository.

  19. OPGW光纤复合架空地线异常发热现场测量分析及仿真%On-site Measurement Based Analysis and Simulation of Abnormal Heating of Optical Fiber Composite Overhead Ground Wires

    Institute of Scientific and Technical Information of China (English)

    彭向阳; 刘毅刚; 张穗强

    2012-01-01

    In allusion to the phenomenon of abnormal heating at the joint where the optical fiber composite overhead ground wire (OPGW) is connected to the truss of substation, the on-site measurement of the induced current and voltage of the grounding circuit of OPGW was performed, and based on the measured results the reason causing the abnormal heating was analyzed. Analysis results showed that the bad contact of OPGW with the truss made the grounding current of OPGW transferring to the circuit of tensional joint and the heating power was larger and concentrated. On this basis the simulation research on induced current of OPGW and heating power are conducted, and simulation results basically conform to the measured data. Research results show that power flow of transmission line, tower grounding resistance and contact resistance of the joint where OPGW is connected to the truss differently influence on the shunt of grounding current of OPGW and the heating power.%针对光纤复合架空地线foptical fiber composite overhead ground wire,OPGW)在变电站构架连接处的异常发热问题,对其接地回路感应电流、电压进行现场实测,分析出异常发热原因是构架处OPGW主接地不良导致接地电流转移至耐张连接回路,且发热功率较大及较集中。据此进一步开展OPGW感应电流、发热功率的仿真研究,仿真与实测数据基本吻合。研究表明线路负荷电流、杆塔接地电阻以及OPGW与构架连接接触电阻对OPGW接地回路分流及发热功率存在不同程度的影响。

  20. A LQR Optimal Method to Control the Position of an Overhead Crane

    Directory of Open Access Journals (Sweden)

    J. Jafari

    2014-05-01

    Full Text Available In this paper, a LQR (Linear Quadratic Regulation optimal method is implemented to control position of an overhead carne. To do this, a tracking formulation of LQR is developed and applied to the system. Hence the dynamic model of the overhead crane is presented, the dynamic of the actuator motor of the trolley is considered. As the parameters of the optimal controller assigned, some simulations are done to show the efficiency of the proposed method.

  1. Overhead shoulder press – In-front of the head or behind the head?

    Directory of Open Access Journals (Sweden)

    Mark R. McKean

    2015-09-01

    Conclusion: Shoulder ROM was within passive ROM for all measures except external rotation for males with the behind the head technique. To avoid possible injury passive ROM should be increased prior to behind the head protocol. Females showed greater spine movements, suggesting trunk strengthening may assist overhead pressing techniques. For participants with normal trunk stability and ideal shoulder ROM, overhead pressing is a safe exercise (for the shoulder and spine when performed either in-front of or behind the head.

  2. 750kV同塔同窗同相序双回紧凑型线路的潜供电流和感应电压%Research on Secondary-Arc Currents and Induced Voltages for 750 kV Compact Double-Circuit Transmission Lines on the Same Tower With the Same Phase Sequence in the Same Tower Window

    Institute of Scientific and Technical Information of China (English)

    王晓彤; 班连庚; 朱普轩; 郑彬

    2011-01-01

    A model of 750kV compact double-circuit transmission lines on the same tower with the same phase sequence in the same tower window is built by use of electromagnetic transient program (EMTP). The problems of secondary-arc currents and recovery voltages, induced voltages and induced currents are studied when the structure of double-circuit compact transmission lines on the same tower with the same phase sequence in the same tower window are applied to full or partial length of the project. Research results show that in the viewpoint of suppressing secondary arc current, recovery voltage, induced voltage and induced current, it is not suitable to adopt such a line structure, i.e., double-circuit transmission lines on the same tower with the same phase sequence in the same tower window, to full length of the project while high voltage shunt reactors are configured. For this reason, following scheme that conventional type is used for the main part of this project and the structure of compact double-circuit transmission lines on the same tower with the same phase sequence in the same tower window is only applied in the sections where the land for line corridors is undersupplied. If the length of the section where the compact double-circuit transmission lines on the same tower with the same phase sequence in the same tower window is applied is short enough, the values of secondary arc current and induced voltages can be suppressed into a rational level. For short transmission lines where the high voltage shunt reactors are not to be configured, if the problem of switching-off induced currents can be solved, it is worthy of consideration to adopt the structure of compact double-circuit transmission lines on the same tower with the same phase sequence in the same tower window to the full lengths of transmission lines.%使用电磁暂态程序(electromagnetic transient program,EMTP),建立了750kV同塔同窗同相序双回紧凑型线路模型.研究了全线或部分采

  3. Characteristics and Clinical Outcomes in Overhead Sports Athletes after Rotator Cuff Repair

    Directory of Open Access Journals (Sweden)

    Tomoyuki Muto

    2017-01-01

    Full Text Available Rotator cuff tears in young overhead sports athletes are rare. The pathomechanism causing rotator cuff tears in young overhead athletes is different from that in aged patients. The purpose of this study was to investigate rotator cuff tear characteristics in young overhead sports athletes to reveal the pathomechanism causing these injuries. This study included 25 overhead sports athletes less than 30 years old with atraumatic rotator cuff tears necessitating repair. Rotator cuff tear characteristics were evaluated intraoperatively, including rotator cuff tear shape and injured rotator cuff tendon. Clinical outcome measures were assessed before surgery and at the final follow-up. In this study, 22 patients reported minimal to no shoulder pain and returned to sports without significant complaints at last follow-up. The isolated infraspinatus tendon was most often injured; the incidence rate of the tear at this site was 32% (8 cases. In the deceleration phase of overhead motion, the eccentric contraction force of the ISP (infraspinatus tendon peaks and the increased load leads to injury at the ISP tendon. The pathomechanism of rotator cuff injuries in young overhead athletes might be not only internal or subacromial impingement, but also these mechanisms.

  4. Technological Aspects: High Voltage

    CERN Document Server

    Faircloth, D C

    2013-01-01

    This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered.

  5. Stray voltage mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Jamali, B.; Piercy, R.; Dick, P. [Kinetrics Inc., Toronto, ON (Canada). Transmission and Distribution Technologies

    2008-04-09

    This report discussed issues related to farm stray voltage and evaluated mitigation strategies and costs for limiting voltage to farms. A 3-phase, 3-wire system with no neutral ground was used throughout North America before the 1930s. Transformers were connected phase to phase without any electrical connection between the primary and secondary sides of the transformers. Distribution voltage levels were then increased and multi-grounded neutral wires were added. The earth now forms a parallel return path for the neutral current that allows part of the neutral current to flow continuously through the earth. The arrangement is responsible for causing stray voltage. Stray voltage causes uneven milk production, increased incidences of mastitis, and can create a reluctance to drink water amongst cows when stray voltages are present. Off-farm sources of stray voltage include phase unbalances, undersized neutral wire, and high resistance splices on the neutral wire. Mitigation strategies for reducing stray voltage include phase balancing; conversion from single to 3-phase; increasing distribution voltage levels, and changing pole configurations. 22 refs., 5 tabs., 13 figs.

  6. High voltage engineering

    CERN Document Server

    Rizk, Farouk AM

    2014-01-01

    Inspired by a new revival of worldwide interest in extra-high-voltage (EHV) and ultra-high-voltage (UHV) transmission, High Voltage Engineering merges the latest research with the extensive experience of the best in the field to deliver a comprehensive treatment of electrical insulation systems for the next generation of utility engineers and electric power professionals. The book offers extensive coverage of the physical basis of high-voltage engineering, from insulation stress and strength to lightning attachment and protection and beyond. Presenting information critical to the design, selec

  7. High voltage test techniques

    CERN Document Server

    Kind, Dieter

    2001-01-01

    The second edition of High Voltage Test Techniques has been completely revised. The present revision takes into account the latest international developments in High Voltage and Measurement technology, making it an essential reference for engineers in the testing field.High Voltage Technology belongs to the traditional area of Electrical Engineering. However, this is not to say that the area has stood still. New insulating materials, computing methods and voltage levels repeatedly pose new problems or open up methods of solution; electromagnetic compatibility (EMC) or components and systems al

  8. Design of Chebyshev coupling circuitry for low-voltage power line carrier communications%低压电力线载波通信的无源耦合电路设计

    Institute of Scientific and Technical Information of China (English)

    刘述钢; 刘宏立

    2011-01-01

    Low-voltage power line is a wired communication channel which is very complex. Its stability is poor and the communications are extremely easy to be destroyed. In this paper, we propose a combination couphng method of a transformer and a Chebyshev band-pass filter. Then we have carefully analyzed the structure of the coupled circuits and the principles of selecting components. The point-to-point communication capabilities are tested in the laboratory and the field, respectively. The results have demonstrated that the method proposed could completely meet the energy consumption information acquisition system for electric power consumer test technology specification of National Grid. The success ratio of the communication surpasses 98% at 110 meters distance in the field environment. At the same time, the ratio is more than 80% at 150 meters distance. This has indicated that the coupling circuit performance can effectively satisfy automatic metering reading.%低压电力线是一种通信环境十分恶劣的有线信道,其通信的稳定性差且极易被破坏.提出一种变压器与Chebyshev带通滤波器相结合的耦合方法,分析了耦合电路的结构和元件的设计原则.分别对实验室和现场环境中点对点通信能力进行数据统计,结果显示完全满足国家电网用电信息采集系统的检验技术规范,在现场环境中距离110m的范围内通信成功率超过98%,距离150 m时也可达80%以上,这表明了依照此方法设计的耦合电路性能完全能满足集中自动抄表要求.

  9. 基于低压电力载波通信的单相智能电表的设计%Design of Single-phase Smart Meter Based on low Voltage Power Line Carrier-Current Communication

    Institute of Scientific and Technical Information of China (English)

    宋树祥; 韦正丛; 梁承福; 何婷婷

    2012-01-01

    In order to remote real-time monitoring and management of single-phase smart meters, a single-phase smart meters has been designed based on carrier chip PL3201 and metering chip 90E24. This design used the low-voltage power line carrier communication, by the direct sequence spread spectrum communication technology, making the system's anti - jamming capability improved significantly. Meanwhile, the design uses the IDT's latest high - precision chip 90E24, the measurement accuracy is better than current industry standards, in a considerable time, the power sector to meet national requirements for measurement accuracy. Practical results show that the design is not only Low-cost, simple, and the measurement of high precision, strong anti -interference, for low carrier concentration meter reading system.%为了对单相智能电表进行远程实时监控管理,设计了一种基于载波芯片PL3201和计量芯片90E24的单相智能电表;该设计把直接序列扩频通信技术应用于低压电力线载波通信,使得系统的抗干扰能力得到显著提升;同时,该设计采用了IDT公司最新推出的高精度计量芯片90E24进行计量,其计量精度优于目前业内水平,能在相当时间内满足国家电力部门对计量精度的要求;实践结果表明,该设计不仅成本低廉、方法简单,且计量精度高、扰干扰能力强,适用于低压载波集中抄表系统.

  10. Mitigation of Unbalanced Voltage Sags and Voltage Unbalance in CIGRE Low Voltage Distribution Network

    OpenAIRE

    Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar; Cecati, Carlo

    2013-01-01

    Any problem with voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM) etc. can be used to mitigate the voltage problems in the distribution system. The voltage problems dealt with in this paper are to show how to mitigate unbalanced voltage sags and voltage unbalance in the CIGRE Low Voltage (LV) test network and net-works like this. The voltage unbala...

  11. A New Secondary Control Approach for Voltage Regulation in DC Microgrids

    DEFF Research Database (Denmark)

    Peyghami Akhuleh, Saeed; Mokhtari, Hossein; Davari, Pooya;

    2016-01-01

    feeders with much voltage drop on the line resistances, the conventional methods may not guarantee the voltage regulation on the load busses. Therefore, in addition to compensate the voltage drop of the primary controller, it is necessary to regulate the voltage of critical loads. In this paper, a new...

  12. Understanding Voltage Decay in Lithium-Rich Manganese-Based Layered Cathode Materials by Limiting Cutoff Voltage.

    Science.gov (United States)

    Yang, Jingsong; Xiao, Lifen; He, Wei; Fan, Jiangwei; Chen, Zhongxue; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2016-07-27

    The effect of the cutoff voltages on the working voltage decay and cyclability of the lithium-rich manganese-based layered cathode (LRMO) was investigated by electrochemical measurements, electrochemical impedance spectroscopy, ex situ X-ray diffraction, transmission electron microscopy, and energy dispersive spectroscopy line scan technologies. It was found that both lower (2.0 V) and upper (4.8 V) cutoff voltages cause severe voltage decay with cycling due to formation of the spinel phase and migration of the transition metals inside the particles. Appropriate cutoff voltage between 2.8 and 4.4 V can effectively inhibit structural variation as the electrode demonstrates 92% capacity retention and indiscernible working voltage decay over 430 cycles. The results also show that phase transformation not only on high charge voltage but also on low discharge voltage should be addressed to obtain highly stable LRMO materials.

  13. 高压输电线路无线电干扰和电磁散射对GPS卫星信号影响测试及分析%Test and Analysis on Effect of High Voltage Transmission Lines Corona Radio Interference and Scattering to GPS Signal

    Institute of Scientific and Technical Information of China (English)

    刘兴发; 尹晖; 邬雄; 张建功; 裴春明; 干喆渊

    2011-01-01

    为分析高压输电线路对邻近作业全球定位系统(GPS)接收信号的影响,从高压输电线路发出的无线电干扰和线路对GPS卫星信号的散射两方面分析了高压输电线路对GPS接收装置观测信号的影响。高压输电线路导线电晕产生无线电干扰主要集中在10MHz以下,通过比较高压输电线路带电前后的定位误差,分析了高压输电线路对GPS接收信号的影响;高压输电线路作为大型构架对GPS卫星信号产生散射,改变卫星信号的幅值、相位和路径,GPS接收装置可能产生定位误差。通过比较离开高压输电线路不同距离测点的定位误差,分析了高压输电线路对GPS接收信号的影响。在交流特高压试验线段下进行现场试验,获得了试验线段带电和不带电运行2种工况下24个测点定位数据。试验结果表明,随着测点离开试验线段0、30、60、120、180m,坐标精度没有明显降低,与距离远近和线路是否带电运行没有明显规律。高压输电线路对邻近作业的GPS接收信号没有影响。%To analyze the interference from the high voltage transmission lines to GPS signal receiving,we analyzed the interference from the high voltage transmission lines including corona radio interference and electromagnetic scattering to GPS satellite signal.The radio interference caused by high voltage transmission line wires corona is mainly below 10 MHz.The electric power fittings and insulator producto radio interference contains more than 30 MHz,due to the influence of high frequency set skin effect,pulse interference current in the conductors reduced in attenuation,so more than 30 MHz interference is considered to be the unconnected-distribution.Through the comparison of high voltage transmission line before and after a charged positioning error analysis,the influence of high voltage transmission lines on GPS receiving signals is analyzed;High voltage transmission lines as a large structure

  14. Voltage verification unit

    Science.gov (United States)

    Martin, Edward J.

    2008-01-15

    A voltage verification unit and method for determining the absence of potentially dangerous potentials within a power supply enclosure without Mode 2 work is disclosed. With this device and method, a qualified worker, following a relatively simple protocol that involves a function test (hot, cold, hot) of the voltage verification unit before Lock Out/Tag Out and, and once the Lock Out/Tag Out is completed, testing or "trying" by simply reading a display on the voltage verification unit can be accomplished without exposure of the operator to the interior of the voltage supply enclosure. According to a preferred embodiment, the voltage verification unit includes test leads to allow diagnostics with other meters, without the necessity of accessing potentially dangerous bus bars or the like.

  15. Specific Considerations on IEC Standardization of Externally Gapped Line Surge Arresters (EGLAs)

    Science.gov (United States)

    Ishizaki, Yoshihiro; Tsuge, Kenji; Kobayashi, Misao; Izumi, Kunikazu; Kawamura, Tatsuo

    The application of externally gapped line surge arresters (EGLAs), which have been developed and established in Japan, is now expanding into many countries. Therefore, the maintenance team 4 (MT4) in the international electrotechnical commission (IEC) technical committee 37 (TC37) for surge arresters advances the standardization works to specify the minimum criteria for requirements and testing methods of EGLAs. EGLAs are effective lightning protection of overhead transmission lines, and have unique required performances originated from the external series gap. The unique required performances of EGLA are insulation coordination performance of EGLA sparkover voltage for lightning overvoltage with the insulator assembly to be protected, withstand voltage performance for switching surge overvoltage and TOV, and follow current interruption performance. This paper discusses the specific issues to be considered for the standardization, such as classification of lightning discharge current rating and a test procedure for follow current interruption performance, based on the Japanese technology through more than twenty years of experience with a large numbers of EGLAs in 22kV to 500kV systems.

  16. Competition Mechanism of Lightning Upward Leaders Issued from UHVDC Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    SHI Wei; LI Qingmin; LU Xinchang; ZOU Liang; SUN Qiuqin

    2012-01-01

    Research on the lightning shielding failure characteristics of UHVDC transmission lines is important for adequate transmission line protection and safe operation of a power grid. Focusing the competition characteristics of upward leaders in the lightning attachment process, this work provides technical reference for efficient evaluations of lightning shielding failures and reliable lightning protection designs of UHVDC transmission lines. The charge simulation method is employed to calculate electric field distributions. Based on the calculation and some data obtained by recent long-gap discharge and lightning observations, the effect of several upward leaders starting from UHVDC transmission lines on lightning attachment processes is studied by numerical simulation. The results show that the upward leader inception is delayed, the propagation velocity is smaller, and the propagation direction of the upward leader is changed with interaction among all upward leaders, which influences the selection of lightning striking point. Therefore, in order to improve the accuracy of calculating the lightning shielding failure rate of UHVDC transmission lines, the interaction characteristics of upward leaders should be taken into account . In addition, an analysis of the influence of operating voltage and the protection angle of UHVDC transmission lines based on competition mechanism of upward leaders is made. It is found that the existence of operating voltage mainly affects the ability of the conductor and the overhead ground wire at the same side to incept upward leaders, while the protection angle mainly affects the position of the "starting points" of upward leaders. The results indicate that positive polar conductors should be installed closer to hillsides and the negative protection angle of towers is suggested.

  17. Evaluation of lightning-induced voltages on low-voltage distribution networks

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Fernando H.; Visacro, Silverio [Federal University of Minas Gerais (LRC/UFMG), Belo Horizonte, MG (Brazil). Lightning Research Center], Emails: silveira@cpdee.ufmg.br, visacro@cpdee.ufmg.br

    2007-07-01

    This paper presents a set of evaluations concerning lightning-induced voltages on low-voltage networks. Such evaluations were performed by means of the Hybrid Electromagnetic Model, a frequency-domain code based on electromagnetic field equations. Sensitivity analyses were developed in order to investigate the role played by the most relevant line parameters on the voltages induced along the electrical system and at the consumer service entrance. The performance of two different low voltage line configurations (conventional versus multiplexed) usually adopted in Brazil was also investigated. The obtained results constitute a contribution to this theme and also provide elements to the development of protection practices to the electrical system and to the consumer against such phenomenon. (author)

  18. Two-Level Incremental Checkpoint Recovery Scheme for Reducing System Total Overheads

    Science.gov (United States)

    Li, Huixian; Pang, Liaojun; Wang, Zhangquan

    2014-01-01

    Long-running applications are often subject to failures. Once failures occur, it will lead to unacceptable system overheads. The checkpoint technology is used to reduce the losses in the event of a failure. For the two-level checkpoint recovery scheme used in the long-running tasks, it is unavoidable for the system to periodically transfer huge memory context to a remote stable storage. Therefore, the overheads of setting checkpoints and the re-computing time become a critical issue which directly impacts the system total overheads. Motivated by these concerns, this paper presents a new model by introducing i-checkpoints into the existing two-level checkpoint recovery scheme to deal with the more probable failures with the smaller cost and the faster speed. The proposed scheme is independent of the specific failure distribution type and can be applied to different failure distribution types. We respectively make analyses between the two-level incremental and two-level checkpoint recovery schemes with the Weibull distribution and exponential distribution, both of which fit with the actual failure distribution best. The comparison results show that the total overheads of setting checkpoints, the total re-computing time and the system total overheads in the two-level incremental checkpoint recovery scheme are all significantly smaller than those in the two-level checkpoint recovery scheme. At last, limitations of our study are discussed, and at the same time, open questions and possible future work are given. PMID:25111048

  19. ACUTE EFFECTS OF DIFFERENT SELF-MASSAGE VOLUMES ON THE FMS™ OVERHEAD DEEP SQUAT PERFORMANCE.

    Science.gov (United States)

    Monteiro, Estêvão Rios; Škarabot, Jakob; Vigotsky, Andrew D; Brown, Amanda Fernandes; Gomes, Thiago Matassoli; Novaes, Jefferson da Silva

    2017-02-01

    The Functional Movement Screen (FMS™) is a battery of tests designed to assess movement competency; the overhead deep squat test, specifically, has been shown to be an accurate predictor of overall FMS™ scores. Self-massage (SM) is a ubiquitous warm-up utilized to increase joint range of motion and, therefore, may be effective for improving performance of the overhead deep squat test. To examine how different doses (30, 60, 90, and 120 seconds) of SM of different areas of the body (plantar fascia, latissimus dorsi, and lateral thigh) affects the score obtained on an overhead deep squat test. Twenty recreationally active females were recruited to be tested on four occasions: sessions one and two consisted of baseline testing, session three consisted of SM applied to the lateral thigh, and session four consisted of SM applied to the lateral torso and plantar fascia. In all SM conditions, at least 90 seconds was required for a change in deep squat score from baseline; therefore, it is concluded that SM the lateral torso, plantar fascia, and lateral thigh for 90 seconds or more are effective interventions for acutely improving overhead deep squat scores. Self-massage appears to be an effective modality for inducing acute improvements in the performance of the FMS™ overhead deep squat in all conditions tested. 2b.

  20. ACUTE EFFECTS OF DIFFERENT SELF‐MASSAGE VOLUMES ON THE FMS™ OVERHEAD DEEP SQUAT PERFORMANCE

    Science.gov (United States)

    Škarabot, Jakob; Vigotsky, Andrew D; Brown, Amanda Fernandes; Gomes, Thiago Matassoli; Novaes, Jefferson da Silva

    2017-01-01

    Background The Functional Movement Screen (FMS™) is a battery of tests designed to assess movement competency; the overhead deep squat test, specifically, has been shown to be an accurate predictor of overall FMS™ scores. Self‐massage (SM) is a ubiquitous warm‐up utilized to increase joint range of motion and, therefore, may be effective for improving performance of the overhead deep squat test. Purpose To examine how different doses (30, 60, 90, and 120 seconds) of SM of different areas of the body (plantar fascia, latissimus dorsi, and lateral thigh) affects the score obtained on an overhead deep squat test. Methods Twenty recreationally active females were recruited to be tested on four occasions: sessions one and two consisted of baseline testing, session three consisted of SM applied to the lateral thigh, and session four consisted of SM applied to the lateral torso and plantar fascia. Results In all SM conditions, at least 90 seconds was required for a change in deep squat score from baseline; therefore, it is concluded that SM the lateral torso, plantar fascia, and lateral thigh for 90 seconds or more are effective interventions for acutely improving overhead deep squat scores. Conclusion Self‐massage appears to be an effective modality for inducing acute improvements in the performance of the FMS™ overhead deep squat in all conditions tested. Level of evidence 2b PMID:28217420