一起800kV GIS设备盆式绝缘子闪络故障分析及建议

Analysis and Suggestions on A Flashover Fault of Basin Insulator in 800 kV GIS Equipment

详细介绍了一起800 kV GIS设备断路器CT气室盆式绝缘子闪络故障,并通过解体检查、对放电痕迹和元素分析推断故障原因是由于盆式绝缘子表面存在“流体异物”使电场畸变。同时在设备长期运行中的累计效应导致盆式绝缘子表面逐渐爬电,而GIS设备在停电检修后供电过程中的VFTO(快速暂态过电压)使爬电贯穿,导致盆式绝缘子沿面闪络故障发生。从而提出异物进入的可能性以及GIS设备隔离开关加装分合闸电阻对抑制VFTO的有效性。

A detailed description of a 800 kV GIS equipment circuit breaker CT gas chamber basin insulator flashover fault,and through disassembly inspection,the discharge traces and element analysis inferred that the cause of the fault is due to the presence of“fluid foreign matter”on the surface of the basin insulator,which makes the electric field distortion.At the same time,the cumulative effect in the long term operation of the equipment causes the surface of the basin insulator to creep gradually,and the VFTO(fast transient overvoltage)during the power supply process of the GIS equipment after the power failure overhaul causes the creep to penetrate,causing the basin insulator to flashover along the surface.happen.Therefore,the possibility of foreign matter entering and the effectiveness of adding opening and closing resistors to the isolation switch of GIS equipment to suppress VFTO are proposed.