一起敞开式隔离开关操作过电压激励罐式断路器微粒放电故障分析

Analysis of Particulate Discharge Fault of Tank Circuit Breaker Excited by Open-Type Disconnector Switching Overvoltage

SF_(6)气体绝缘金属封闭开关设备又称组合电器(简称"GIS"),具有占地面积小、不受外界环境影响、运行可靠性高、免维护的优点,在电力系统得到广泛应用,组合电器故障率直接影响到电网稳定.介绍了一起252 kV罐式断路器在同间隔隔离开关操作时灭弧室内发生放电的故障,综合录波数据、解体情况分析,通过隔离开关操作过电压仿真计算、现场局部放电试验比对分析,得出故障原因为动静主触头异常磨损,产生较多金属颗粒,在操作振动(气动机构)和分合闸气流扰动下,于动触头侧的屏蔽罩下方罐体处积聚,隔离开关分闸过程中产生高频过电压,传导至断路器动触头侧,加剧罐体处积聚的金属颗粒跳动,引发屏蔽罩底部对下方罐体放电,并为后续改造提供了建议.

SF_(6)gas insulated metal enclosed switchgear,also known as Gas Insulated Switchgear(GIS for short),has the advantages of small footprint,immunity from external environmental impacts,high operational reliability,and maintenance free,and is widely used in power systems.The failure rate of GIS directly affects the stability of power grid.This paper introduces a discharge fault of 252 kV tank circuit breaker in the arc-extinguishing chamber during the operation of the disconnector at the same interval.With the recording data combined and the disassembly condition analyzed,and through the simulation calculation of the disconnector switching overvoltage and the comparative analysis of field partial discharge test,the paper comes to the following causes of the fault:Abnormal wear of the dynamic and static main contacts leads to more metal particles,which accumulate in the tank under the shield on the side of the moving contacts in the case of operating vibration(pneumatic mechanism)and the disturbance of the switching airflow.During the opening process of the disconnecting switch,high-frequency overvoltage is generated and transmitted to the moving contact side of the circuit breaker,which aggravates the dance of the metal particles accumulated in the tank and causes the bottom of the shield cover to discharge to the tank below.Thus,the paper provides suggestions for subsequent renovations.