一例误上电保护误动作的事故分析

Analysis of an Accidental Power-on Protection Malfunction

误上电保护作为机组启动及并网过程中的重要保护,通常采用发电机变压器组出口断路器、灭磁开关辅助接点作为逻辑判别条件,而因开关辅助接点问题造成的保护误动时有发生。针对一起机组启动中因逻辑设定的常开常闭辅助接点与外回路接线不一致导致的误上电保护误动作案例,从误上电保护的设计、校验、运行维护等方面提出了相应的建议。

As important protection in the process of unit start-up and grid-connection,generator transformer group outlet circuit breaker and demagnetizing switch auxiliary contacts are usually used as logical identification conditions,and the protection malfunction caused by the switch auxiliary contact problem often occurs.In order to deal with a case of accidental power-on protection malfunction caused by the inconsistency between the normally open and normally closed auxiliary contacts set by logic and the wiring of external circuit during unit startup,corresponding suggestions for the design,verification,operation and maintenance of accidental power-on protection are put forward.