换流阀三角形侧零序环流对阀短路保护的影响

Influence of Converter Transformer D-bridge Zero Sequence Circulating Current on Valve Short Circuit Protection

笔者研究了换流阀三角形侧零序环流对阀短路保护误动作的影响。通过分析葛洲坝换流站两次阀短路保护无动作的情况,根据双极阀短路保护判据,指出零序环流使CT暂态饱和是这两次事故的主要原因,同时相应地给出了解决办法,为将来高压直流更好的安全稳定运行提供参考。

This paper studies the influence of converter transformer D-bridge zero sequence circulating current on valve short circuit protection. A case study indicates the fault trips of D-bridge differential protection due to CT transient saturation in Gezhouba converter station leads to breakdown of equipments for two times, according to the criterion of valve short circuit protection. Corresponding methods are presented for solving this problem.