±800kV 宾金直流接地极线路电流不平衡异常分析

Analysis on Abnormal Unbalanced Current of ±800kV Binjin DC Earthed Electrode Line

摘要:

分析了2016年4月16日±800kV宾金直流输电工程极Ⅱ线路遭受雷击后绝缘击穿的故障，以及在极Ⅱ线路第2次再启动过程中接地极引线不平衡保护动作的原因。通过故障录波分析和登塔检查，发现宜宾换流站接地极线路一侧导线绝缘在极Ⅱ线路接地故障后发生过电压击穿，在重启过程中持续流过直流续流，并提出通过改进接地极建立绝缘配合解决此类问题。

Abstract:

Since the commissioning of the YiBin－JinHua project，several abnormal operation conditions of grounding electrode lead have been observed． In this paper，the operating conditions of this line are analyzed based on the system parameters and electrical quantities measured under various normal and abnormal conditions． Meanwhile，the reasons for the tripping of unbalanced protection are studied． The results show that this phenomenon is due to the voltage imbalance during the DC restart period． Therefore，some constructive suggestions are provided for the design of grounding electrode line．