500kV线路保护两侧重合闸定值问题分析与处理

Analysis and Processing on Reclosing Value Setting Problem of the 500kV Transmission Line Protection with Both Sides

伊敏电厂伊换I线5053断路器U相电流互感器烧损,电流互感器与断路器连接母线脱落,造成U相接地故障。伊敏换流站伊换Ⅰ线线路保护U相差动保护动作,5043断路器重合于故障点未能成功断开故障电流,造成5043断路器损坏。分析原因为故障线路两侧重合闸时间定值设置不当,使5043断路器未能成功断开故障电流所致。重新整定线路两侧断路器保护重合闸定值时限,使故障情况下两侧断路器保护有序配合,以避免线路故障时两侧断路器同时重合于故障而造成断路器损坏事故。

In Yimin Power Plant, the U phase current transformer of the changed I line 5053 circuit breaker breakdown.The bus current connect transformer with the circuit breaker off, resulting in U phase grounding fault. Yimin Converter Station U phase differential protection of the changed I line protection operating, side breaker 5043 failed cut the fault current because of it reclosing to fault point. Reason analysis was that the 5043 breaker could not break the fault current successfully because the reclosing times on both sides of the line were not set correctly. The reclosing time of the breakers on the both sides of the line should be reset to ensure that the breaker protections can coordinate orderly under fault conditions. It can avoid that the breakers on both sides reclose at the same time when the fault still exists under fault conditions and the breakers are destroyed.