摘要
针对一起220 kV线路纵联零序方向保护误动事件,分析了环网系统接地故障零负序电流分布特征,结果表明在环网系统线路区外特定地点发生接地故障时,可能出现线路同一侧零负序功率方向相反的情况,若两侧功率方向判据方法不一致,可能导致线路纵联零序方向保护误动。根据误动原因分析,提出了改进措施,对提升系统线路纵联保护可靠运行有良好的借鉴作用。
In view of a malfunction event of 220 kV line pilot zero-sequence direction protection, this paper analyzed the distribution characteristics of the zero-negative-sequence current of grounding fault in the loop network system. The analysis shows that the zero-negativepower on one end of a line could be in the opposite direction when the grounding fault occurs at a specific location outside of the line in the loop network system. If the power direction criterion on two ends of the line is inconsistent, it may cause the malfunction of the line pilot zero-sequence direction protection. On the basis of the analysis of malfunction causes. This paper puts forward some improving measures, which could be used to improve the reliability of the line pilot protection with good reference functions.
引文
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