500kV失灵保护误动分析与反措

Analysis of 500kV Failure Portecion Misoperation and Its Anti Accident Measures

阐述了一起500kV失灵保护误动事故,其误动原因是母线保护失灵回路光耦开入回路设计不完善,动作电压不满足55%~70%额定直流电压要求,当光耦正端接地时,造成光耦开入回路误导通而母线失灵保护误动作出口。根据国家电网公司继电保护反事故措施要求,对母线保护开入回路插件进行更换,以满足动作电压要求。

This paper describes a 500kV failure portccion misoperation accident, the reason of misoperation is that the design of busbar protection failure loop＇ s optocoupler open circuit is not complete, its action voltage could not satisfy 55%-70% DC voltage range. Optocoupler＇ s positive is grounded, which leads to circuit＇ s conduction and busbar failure protection trip. According to state grid corporation＇ s anti accident measurement, open circuit is replaced, which satisfying action voltage.