直流运行方式对接地极线路耐雷性能影响分析

Analysis on Influence of Different Operation Modes of HVDC System on the Lightning Protection Performance of Grounding Electrode Lines

针对某直流线路接地极线路连续出现多次雷击故障,结合线路雷电防护措施情况,以不同运行方式下接地极线路雷击闪络建弧仿真计算为手段,分析了事件原因,重点研究了不同运行方式下雷击对线路的影响。结果表明:当直流系统以单极大地回路方式运行时,接地极线路遭雷击闪络后易建立稳定电弧,造成直流系统故障风险较高,而以两端中性点接地双极平衡方式运行时,接地极线路遭雷击闪络后无法建弧,造成直流系统故障概率较低;建议在雷雨多发季节,直流系统应尽量避免长时间以单极大地回路方式或两端接地双极不平衡方式运行。

As the grounding electrode line of a HVDC transmission system repeatedly suffered lightning faults during a short period, the reason of the event, especially the effects which lightning strike may bring to the grounding electrode line were analyzed by simulation calculation of arc＇s stability after lightning stroke under different operating modes based on the lightning prevention measures of the line. Conclusion can be drawn that： the grounding electrode line suffers high risk of lightning failure when operating in the monopolar ground circuit mode because the lightning flashover can easily build stable arc between arcing horn, but has a relatively low probability of lightning failure when operating in the double neutral-points grounding and bipolar symmetric mode as stable arc can＇t been built. Suggestion was proposed that HVDC transmission system must be avoided operating for a long time in the monopolar ground circuit mode or the double neutral-points grounding and bipolar asymmetric mode during the thunderstorm season.