±500kV换流站复合绝缘设备雨闪事故分析及预防措施

Analysis and Preventive Measures of Rain Flashover Fault of DC Composite Insulation Devices in ±500 kV Converter Station

针对近年来±500 kV换流站直流复合绝缘设备发生的雨闪故障,通过对复合绝缘设备的外闪机理、外闪后性能影响,以及多起雨闪事故的特征及原因和现场处置措施进行分析后发现,复合绝缘子的大伞间距及伞伸出参数、爬电距离、表面污秽程度、复合绝缘老化程度和雨量大小等是引起复合绝缘设备发生雨闪的关键因素。在此基础上,提出了及时开展复合绝缘设备绝缘评估、加强巡查、及时清污、加装辅助伞裙、更换大爬距设备等有效预防复合绝缘设备雨闪事故发生的措施。

Aiming at rain flashover faults of DC composite insulation device in ±500 kV converter station happened in recent years. After the analysis of the mechanism of external flashover, the influence of external flashover to performance, and characteristics, reasons and field disposal measures of several rain flashover faults, it is found that key factors that cause the rain flashover of composite insulation devices are including： the large umbrella spacing of composite insulation, the extending parameters of umbrella, the creepage distance, the pollution degree of surface, the aging degree of composite insulation and the amount of rainfall and so on. Based on that, measures to prevent effectively the rain flashover fault of composite insulation device are proposed including： evaluating the insulation of composite insulation devices, strengthening patrol and inspection, clearing timely pollution, adding auxiliary umbrella skirt, replacing with larger creepage distance devices and so on.