Simulation Study on Restrain Strategy for No-load Switching Overvoltage of UHV Transmission Line

Abstract

UHV transmission lines are characterized by small distributed resistance and inductance, large distributed capacitance, long transmission lines, etc., and their overvoltage is more serious. The overvoltage multiple is an important basis for determining the insulation level of the system. Therefore, by restraining the overvoltage we can reduce the insulation level, reduce the construction investment and reduce the damage of overvoltage to various power equipment. In this paper, the noload switching overvoltage of 1000kv transmission lines is taken as the research object. By using MATLAB software, the trategies,such as, circuit breakers with closing resistances, installing lightning arresters and the multistage closing resistances are matched with the installation of the lightning arresters are used to restrain the no-load switching overvoltage. The simulation results show the use of closing resistance and the installation of lightning arresters at both ends of the line we can restrain the maximum overvoltage of the line to a certain extent, the installation of lightning arresters at both ends of the line is better than the use of closing resistance to restrain the maximum overvoltage, but both can not meet the voltage limit requirements of uhv transmission lines, and the waveform has some distortion. By combinating of multistage closing resistances and the installation of lightning arresters at both ends of the transmission line we can effectively restrain the overvoltage of uhv transmission line, and can damp the waveform oscillation, which has certain practical value.