330kV氧化锌避雷器故障诊断分析及处理

Fault Diagnosis Analysis and Treatment of 330 kV Zinc Oxide Arrester

避雷器是保护电力系统正常运行的重要设备,其安全性能对于电力网络可靠运行具有重要意义。介绍了一起330 kV氧化锌避雷器故障事件,通过对设备进行一次检查及试验、解体检查、直流泄漏及绝缘试验、扫描电镜分析以及污秽取样分析,确定故障原因为在故障前系统发生一次过电压冲击扰动,避雷器在经受系统过电压后,避雷器电阻片因本身质量存在缺陷,导致电阻片进一步劣化,劣化电阻片发热并发生热崩溃,进而导致上节内部芯体贯穿性放电击穿、内部闪络。上节防爆口因闪络动作后,喷溅出的铝蒸汽等金属粉末附着在下节避雷器瓷套表面,导致外绝缘间隙距离缩短、电场分布发生变化,从而在外表面发生贯穿性放电。该故障分析对避雷器选型和检测提出更高要求,也为今后同类隐患排查提供重要经验参考。

Lightning arrester is an important equipment to protect the normal operation of power system,and its safety performance is of great significance to the reliable operation of power network.A failure event of 330 kV zinc oxide arrester is introduced.Through the inspection and test of the equipment,disintegration inspection,DC leakage and insulation test,scanning electron microscope analysis and pollution sampling analysis,it is determined that the failure cause is an overvoltage shock disturbance occurred in the system before the failure.After the arrester is subjected to the system overvoltage,arrester resistance sheet due to its own quality defects,leading to further deterioration of the resistance sheet,deteriorated resistance sheet heating and thermal collapse,resulting in the internal core of the upper section penetration discharge breakdown,internal flassion.Due to the flasshy action of the upper section explosion-proof port,the metal powder such as aluminum steam spilled out adheres to the porcelain sleeve surface of the lightning arrester in the lower section,leading to the shortening of the distance between the outer insulation gap and the change of the electric field distribution,resulting in the penetration discharge on the outer surface.