考虑先导电流的架空输电线路雷电反击研究OA

As the flashover criterion of insulator string in the calculation of lightning protection level of o-verhead transmission lines,the leader development method has been widely used at home and abroad.During the establishment of the leader channel,a large amount of charge will accumulate in the leader channel,which can be equivalent to the leader current flowing through the discharge channel,and it is generally believed that the leader current is proportional to the leader development speed.However,the leader current is usually ignored in the current insulator string flashover calculation based on the leader development method.Based on the CIGRE recommended formula,the author calculates the leader devel-opment speed and leader current,uses controllable time-varying resistor,TACS controllable switch and MODEL module to establish an insulator string flashover model considering the leader current in EMTP/ATP,and carries out the simulation of lightning protection level and lightning intrusion wave overvoltage of 500 kV and 110 kV overhead transmission lines and 500 kV typical substation,and compares the flash-over characteristics of the leader current on the insulator string,the lightning protection level of overhead transmission lines,the simulation of lightning protection level,and the effect of lightning intrusion wave overvoltage levels in substation equipment of 500 kV and 110 kV overhead transmission lines.It is found that ignoring the leader current will underestimate the lightning protection level of the transmission line,overestimate the overvoltage amplitude of the lightning intrusion wave and the high-frequency component in the overvoltage,and consider the influence of tower height and grounding resistance,and propose a correction coefficient of 500 kV and 110 kV overhead transmission line double-return drum tower coun-terattack lightning protection level considering the leader current.