一起500kV GIS内部机械运动部件缺陷引起的局部放电分析OA

In response to the abnormal partial discharge defect of the gas insulated switchgear(GIS)circuit breaker in a 500 kV substation,ultrasonic and ultra-high frequency(UHF)methods are used for on-site live detection and positioning,while X-ray is adopted for defect verification.The video endoscope is employed to examine the distribution of foreign matters,and the scanning electron microscope(SEM)combined with energy dispersive spectrometer(EDS)is applied for component analysis.Combined with the full-process disassembly inspection after returning to the factory,the source of foreign matters is traced and the causes of defects are analyzed.The direct cause of the abnormal partial discharge is electric field distortion caused by foreign matter accumulation resulting from defects in internal mechanical moving parts of the GIS.The root cause is continuous foreign matter accumulation due to equipment design deficiencies and inadequate production process control,which ultimately leading to partial discharge.A four-in-one strategy incorporating equipment rectification,specialized inspection,enhanced monitoring,and process optimization is proposed for treatment,operation and maintenance prevention and control,providing a technical reference for fault diagnosis of similar equipment.