500 kV GIS断路器单相接地故障分析和处理

Analysis and Treatment of a Single-phase Grounding Fault in 500 kV GIS Circuit Breaker

基于某大型水电站500 kV GIS开关站1台发变组出口断路器在分闸状态发生单相接地故障,造成该断路器所在联合单元进线串短线差动保护动作,1台运行机组从系统解列。通过对保护故障录波、故障范围SF6隔室气体成分分析和故障断路器解体检查,明确了故障原因,通过更换断路器解决了故障。经对故障原因进行深入探讨,提出了有针对性的设备运行维护策略。

A single-phase grounding fault of a circuit breaker in its opening state occurred in a 500 kV GIS switch station in a large hydropower station,which led to the short line differential protection action on the joint incoming line of the units where the circuit breaker is located,and the disconnection of an operating unit.With the analysis of the protection fault recording,composition of the SF6 gas in the compartments in the fault range,and the fault circuit breaker,the cause of the fault is determined.By replacing the fault breaker,the problem is successfully solved.Also,some targeted operation and maintenance suggestions are proposed with an in-depth discussion of the fault.