220kV同塔双回线路雷击双回同跳防雷改造

Lightning Protection for the Flashover of 220kV Double-Circuit Transmission Line on the Same Tower

同塔双回输电线路双回同跳严重威胁电网的安全稳定运行。内蒙古地区包青线220k V同塔双回输电线路发生过2次雷击造成双回同跳事故,本文采用EMTP软件对事故进行仿真复现。仿真计算结果表明:一定幅值的雷电流击中塔顶时,可能造成与现场实际吻合的双回线路C相同跳。通过比较绝缘子串两端雷电过电压中几个分量对最终闪络电压的贡献度得知,220 k V线路工频相位是影响双回输电线路ABC三相闪络顺序的主要原因。降低杆塔冲击接地电阻和安装线路避雷器是提高耐雷水平和降低雷击跳闸率最简单可行的措施。当非全相安装避雷器时,若每回路安装一支避雷器,建议安装在下相;若每回路安装两支避雷器,建议安装在中相和下相。

Double-circuit transmission line double-circuit flashover is a big accident,which is bad for the stability of the power system. There were two double-circuit transmission line double-circuit flashover hitting in Baotou Electric Power Corporation,the paper uses EMTP lightning flashover model to simulate. The results show that when the lightning hit the top of the tower will cause the C-phase flashover,which is consistent with actual running situation. Through the comparison of the contribution of several components in lightning overvoltage to the final overvoltage on the insulator,we learn that power frequency voltage is the main reason affecting double-circuit transmission line flashover＇s order. Reducing the impulse grounding resistance and installing line lightning arrester are the most effective ways of improving the lightning resisting level and reduce lightning trip-out rate. According to the result analysis,if only one-phase line arresters are installed on 220 k V doublecircuit transmission line,they should be installed on middle-phases or bottom-phase;if two line surge arresters are installed on two phase on every circuit,they should be mounted on two middle and two bottom phases.