雷击交流侧同塔双回线路时换流站过电压特性

The Overvoltage Characteristics of Converter Station When Lightning Strikes to the Double-Circuit System of 500kV AC Side

超高压电网多采用同塔双回或多回线路,由于杆塔较高,遭受雷击时可能造成多回线路闪络。依托某换流站500 kV交流侧系统,利用EMTP/ATP建立电站雷电侵入波过电压计算模型,研究换流站交流侧同塔双回线路遭受雷击时站内设备上过电压特性以及与单回线路的区别。结果表明:雷击同塔双回线路杆塔时,在两回线路均闪络的情况下,换流站设备上反击侵入波过电压在双线运行方式下幅值远高于单线运行方式,且过电压最大值一般是在雷击进线段第二基杆塔TW_2时出现,反击过电压特性与雷击单回线路差异较大;而同塔双回线路绕击侵入波过电压规律与单回线路类似,单线运行方式下设备过电压高于双线运行方式,且过电压最大值一般出现在雷电绕击距离换流站最近的TW1附近线路。

Double-circuit and multi-circuit lines are widely used in the EHV power grid and may cause multiple line flashovers when lightning strikes to the lines due to the high tower.This paper is based on the 500 kV AC part of a converter station and building the model of computing lightning invasion wave overvoltage of the converter station by means of EMTP age in the double circuit system and the differences with single circuit system.The results show that,for the double circuit system and in the case where both lines are flashing,the back flashover overvoltage on equipment is much higher in the operation mode with two lines than the operation mode with one line and it generally maximizing when the second tower(TW2)is struck,and the characteristic of back flashover invade overvoltage is obvious different with the single circuit system;The characteristic of shielding failure invade overvoltage on equipment in the double circuit system is similar to the single circuit system,and the overvoltage is higher in the operation mode with one line than the operation mode with two lines and it generally maximizing when the line on the first tower(TW1)is struck owe to the short distance.