The Experts below are selected from a list of 2109 Experts worldwide ranked by ideXlab platform
Shao Fangyin - One of the best experts on this subject based on the ideXlab platform.
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Phase Conductor configuration and power frequency electromagnetic environment of uhv transmission lines in china
Power system technology, 2005Co-Authors: Shao FangyinAbstract:The strategy and measures for solving the power frequency electromagnetic environment problems in developing their UHV transmission lines in former USSR, Japan and the US are briefly introduced and analyzed. Based on the construction and operation experiences gained from 500kV transmission lines in China a new Phase Conductor configuration scheme (compact line with verse triangle configuration of Phase Conductors) is proposed. Distributions of power frequency electric field and magnetic field for the above mentioned three types of UHV transmission lines abroad and that of the proposed scheme to be developed are calculated under the same control condition. The obtained results should be helpful in choosing and determining the Phase Conductor configuration and the type of tower of the first UHV lines in China.
Zygmunt Piatek - One of the best experts on this subject based on the ideXlab platform.
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Total Eddy Currents Induced in Screens of a Symmetrical Three-Phase Single-Pole Gas-Insulated Transmission Line (GIL)
Advances in Electrical and Electronic Engineering, 2011Co-Authors: Zygmunt PiatekAbstract:In the paper we discuss the question of eddy currents induced in screens of a symmetrical three-Phase singlepole gas-insulated transmission line (GIL). First, we determine the eddy currents induced in the tubular screen by the magnetic field of self-current of the Phase Conductor. Then the magnetic field in the external parallel Phase Conductor is presented by means of a vector magnetic potential as Fourrier series. In the non-conducting external and internal area of the screen we use Laplace equation for the magnetic field strength taking into account the reverse reaction of eddy currents induced in the screen. In the conducting screen we apply Helmholtz equation for eddy currents density. Using classical boundary conditions we determine the density of the currents. The solutions obtained are used to determine the total eddy currents induced in all the screens of the GIL under consideration.
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IMPEDANCES OF FINITE-LENGTH ISOLATED Phase BUSDUCTS
2008Co-Authors: Zygmunt PiatekAbstract:The self and mutual impedances of a three-Phase high current transmission line with isolated Phases are calculated. The Phase Conductors and their sheaths are presented as a system of parallel Conductors, whose voltage drops are described by a system of three-dimensional integral Fredholm's equations of the second kind with weakly singular kernels. Next, defined are self and mutual impedances of the Phase Conductors and sheaths of a finite length gas-insulated transmission line with isolated Phases (GIL). These impedances are expressed in terms of the densities of self currents as well as densities of currents induced in the Conductors by magnetic field of other Phase Conductors. This allows including the skin and proximity effects. The proximity effect between the Phase Conductor and its sheath and sheaths of the neighbouring Phases is also taken into account. The computation of self and mutual impedances for the case of a single-Phase GIL and a system of two non-coaxial parallel tubular Conductors is discussed in detail. Analytical formulae for self and mutual impedances of the above systems are obtained by determining the same quantities for a three-Phase flat GIL with isolated Phases.
Rong Zeng - One of the best experts on this subject based on the ideXlab platform.
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Influence of ground wire on the initiation of upward leader from 110 to 1000kV AC Phase line
Electric Power Systems Research, 2016Co-Authors: Xi Wang, Rong Zeng, Farhad RachidiAbstract:The problem of upward leader inception from transmission lines has not been thoroughly discussed, largely because of the difficulty to obtain experimental data under natural circumstances. Previous studies have primarily examined reduced-scale experiments or single-Phase test lines. In this context, a real-size experimental system aimed at studying upward leader characteristics on both the Phase Conductor and ground wire is designed in this study. The results associated with real-size experiments corresponding to 110 kV, 220 kV, 500 kV and 1000 kV AC transmission lines, including the Phase Conductor and ground wire, are presented and discussed. It is shown that as the triggering voltage on the Phase Conductor increases, the streamer and leader incept earlier for a leader emerging from the Phase Conductor, and incept later for a leader emerging from the ground wire. The increase of the triggering Phase angle corresponds to a higher voltage on the Phase Conductor, thereby increasing the strike probability on the Phase Conductor. The leader velocity and charge density present, in general, an increasing trend for the Phase Conductor as a function of the Phase angle, while an opposite trend is observed for the leader emerging from the ground wire except for some special occasions. It is also determined that the Phase Conductor leader velocity is larger for a higher voltage class, while the charge density associated with the leader emerging from the Phase Conductor is smaller for a higher voltage class. (C) 2015 Elsevier B.V. All rights reserved.
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Characteristics of Upward Leader Emerging From a Single-Phase Conductor With Different Voltage Class
IEEE Transactions on Power Delivery, 2015Co-Authors: Xi Wang, Rong ZengAbstract:In order to improve the shielding effect of the transmission line, the accurate line system design is significant. The electrogeometric model and leader progression model are two typical and most widely used numerical analysis models to analyze the shielding failure performance. However, both models call for more experimental evidence for accurate application. This paper investigates the characteristics of an upward leader emerging from 110-, 220-, 500-, and 1000-kV single-Phase Conductors through simulated experiments, and the Conductor parameters and heights adopted are similar to the actual transmission lines in operation. The ac voltage generator is connected to the Conductor to apply an operating voltage to the Conductor. The influence of bundle number and Conductor height on the upward leader is also discussed in detail. The obtained characteristics of an upward leader will be helpful to build appropriate numerical analysis models for the shielding failure of the transmission line.
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Numeral analysis model for shielding failure of transmission line under lightning stroke
IEEE Transactions on Power Delivery, 2005Co-Authors: Rong Zeng, Jaebok Lee, Sughun Chang, Zhicheng GuanAbstract:The shielding failure is the occurrence of a lightning stroke that bypasses the overhead ground wires and terminates on the Phase Conductors. The correct design to improve the shielding effect of transmission line to lightning is one of the key problems of transmission line design. A numerical analysis model for shielding failure of transmission line based on electromagnetic field theory is proposed in this paper. The electrical field of the system including lightning leader, transmission line and ground is solved, the range of lightning current striking the Phase Conductor is obtained, and the shielding failure probability of transmission line is calculated. The lightning leader model and the critical breakdown electrical field intensity of long gap are discussed. The analyzed results by numerical analysis model are compared with those by the electrogeometric model.
Zygmunt Pjatek - One of the best experts on this subject based on the ideXlab platform.
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METHOD OF CALCULATING TOTAL EDDY CURRENTS INDUCED IN SCREENS OF A SYMMETRICAL THREE-Phase SINGLE-POLE GAS-INSULATED TRANSMISSION LINE
2008Co-Authors: Zygmunt PjatekAbstract:The problems of eddy currents induced in screens of a symmetrical three-Phase single-pole gas-insulated transmission line (GIL) are discussed. The solution starts from determining the eddy currents induced in the tubular screen by the magnetic field of self-current of the Phase Conductor. Then the magnetic field in the external parallel Phase Conductor is presented by means of the magnetic vector potential as a Fourier series. In the non-conducting external and internal areas of the screen the Laplace equation is used for the magnetic field strength taking into account the reverse reaction of the eddy currents induced in the screen. The domain of the conducting screen is described by the Helmholtz equation for the eddy currents density supplemented with the classical boundary conditions. The solutions obtained are used to determine the total eddy currents induced in all the screens of the GIL under consideration.
Xi Wang - One of the best experts on this subject based on the ideXlab platform.
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Influence of ground wire on the initiation of upward leader from 110 to 1000kV AC Phase line
Electric Power Systems Research, 2016Co-Authors: Xi Wang, Rong Zeng, Farhad RachidiAbstract:The problem of upward leader inception from transmission lines has not been thoroughly discussed, largely because of the difficulty to obtain experimental data under natural circumstances. Previous studies have primarily examined reduced-scale experiments or single-Phase test lines. In this context, a real-size experimental system aimed at studying upward leader characteristics on both the Phase Conductor and ground wire is designed in this study. The results associated with real-size experiments corresponding to 110 kV, 220 kV, 500 kV and 1000 kV AC transmission lines, including the Phase Conductor and ground wire, are presented and discussed. It is shown that as the triggering voltage on the Phase Conductor increases, the streamer and leader incept earlier for a leader emerging from the Phase Conductor, and incept later for a leader emerging from the ground wire. The increase of the triggering Phase angle corresponds to a higher voltage on the Phase Conductor, thereby increasing the strike probability on the Phase Conductor. The leader velocity and charge density present, in general, an increasing trend for the Phase Conductor as a function of the Phase angle, while an opposite trend is observed for the leader emerging from the ground wire except for some special occasions. It is also determined that the Phase Conductor leader velocity is larger for a higher voltage class, while the charge density associated with the leader emerging from the Phase Conductor is smaller for a higher voltage class. (C) 2015 Elsevier B.V. All rights reserved.
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Characteristics of Upward Leader Emerging From a Single-Phase Conductor With Different Voltage Class
IEEE Transactions on Power Delivery, 2015Co-Authors: Xi Wang, Rong ZengAbstract:In order to improve the shielding effect of the transmission line, the accurate line system design is significant. The electrogeometric model and leader progression model are two typical and most widely used numerical analysis models to analyze the shielding failure performance. However, both models call for more experimental evidence for accurate application. This paper investigates the characteristics of an upward leader emerging from 110-, 220-, 500-, and 1000-kV single-Phase Conductors through simulated experiments, and the Conductor parameters and heights adopted are similar to the actual transmission lines in operation. The ac voltage generator is connected to the Conductor to apply an operating voltage to the Conductor. The influence of bundle number and Conductor height on the upward leader is also discussed in detail. The obtained characteristics of an upward leader will be helpful to build appropriate numerical analysis models for the shielding failure of the transmission line.