乐滩水电站发电机出口断路器控制回路断线故障分析与处理

Fault Analysis and Treatment of Generator Outlet Circuit-Breaker Control Loop in Letan Hydropower Station

笔者针对乐滩水电站3号发电机出口断路器合闸时监控系统报"第一组控制回路断线""第二组控制回路断线"信号,发电机出口断路器分闸时不报警情况的问题,进行故障分析与处理。通过对现场信号反馈并结合图纸将3号发变组保护改造部分与改造前进行对比分析,从监控、保护到断路器二次接线部分逐一排查找原因,最终确定是断路器监控合闸回路正负电源不取自同一空开的原因所致,并采取重新接线将断路器监控合闸回路电源引自同一空开正负电源取电。通过处理,消除了3号发电机出口断路器合闸时监控系统报"第一组控制回路断线""第二组控制回路断线"信号。结合理论及现场实际分析处理故障,对机组安全稳定运行具有重要意义。

The author carries out fault analysis and treatment for the problems that the monitoring system reports the signal of "the first of control loop disconnection" and "the set of control loop disconnection"when the No.3 generator outlet circuit-breaker closes in Letan Hydropower Station and the alarm does not occur when the generator outlet circuit-breaker opens.Through the feedback of the field signal and the comparison and analysis of the protection transformtion part of No.3 generator-transformer unit with that before the transformation,the reasons are investigated one by one from the monitoring,protection to the secondary wiring part of the circuit-breaker.Finally,it is determined that the positive and negative power supply of the circuit-breaker monitoring and closing circuit is not taken from the same open space,and the reconnection is adopted to lead the power supply of the circuit-breaker monitoring and closing circuit from the same open positive and negative power supply.Through processing,the signals of "the first set of control disconnection" and "the second set of control loop disconnection" reported by the monitoring system when the No.3 generator outlet circuit-breaker closes are eliminated.Combined with the theoretical and practical analysis,the fault is processed,which is of great signifiance to the safe and stable operation of the unit.