220 kV金属氧化物避雷器异常原因的分析

Analysis of Abnormal Causes of 220 kV Metal Oxide Arrester

基于某220 kV氧化锌避雷器运行中持续电流检测结果异常故障,通过停电试验、解体分析发现瓷套法兰周围锈蚀严重,内部电阻片受潮,判断因法兰螺栓紧固不均匀、密封圈材质缺陷、压缩率过大等原因造成法兰面密封失效,潮气侵入避雷器内部,导致电阻片受潮、电气性能劣化,引起避雷器泄漏电流异常和红外热像测温异常。确认故障原因后,结合运检经验,提出改进密封盖板材质、标准化圆形法兰密封紧固工艺、加强密封圈等密封组件质量抽检等预防措施,以避免类似故障的发生。

A 220 kV zinc oxide surge arrester in operation has abnormal continuous current detection results.Through power outage test and disassembly analysis,it is found that the periphery of the porcelain sleeve flange is severely corroded,and the internal resistance piece is damp.the sealing failure of the flange face due to uneven tightening of flange bolts,material defects of the sealing ring,excessive compression rate,etc.Moisture intrudes into the arrester,resulting in damp resistance and deterioration of electrical performance,abnormal leakage current of arrester and abnormal infrared thermal image temperature measurement.After confirming the cause of the fault,combined with the experience of operation inspection,preventive measures such as improving the material of sealing cover plate,standardizing the sealing fastening process of circular flange and strengthening the quality sampling inspection of sealing components such as sealing ring are put forward to avoid similar faults.