污秽绝缘子安装并联间隙的雷电击穿特性分析

为了分析不同盐密值下污秽绝缘子并联间隙的雷电冲击击穿特性，以SC-210瓷横担绝缘子为例进行雷电冲击试验，通过对比清洁和污秽绝缘子的电场仿真结果，对试验时多次发生沿绝缘子表面闪络的现象进行了分析. 试验和分析表明:安装并联间隙的SC-210瓷横担，其雷电冲击击穿电压U_50%随盐密值增加而降低，更容易趋于饱和；污秽绝缘子与防雷间隙的雷电冲击伏秒特性曲线逐渐相交，试验时多次发生沿绝缘子表面闪络的现象. 研究结果建议在进行并联间隙与绝缘子串的绝缘配合整定时，应考虑绝缘子表面污秽对闪络/击穿部位的影响. 

Analysis of Lightning Breakdown Characteristics of Contaminated Insulators in Parallel Clearance

To analyse the lightning impulse breakdown characteristics of the parallel gaps of contaminated insulators with different salt densities, the SC-210 porcelain cross-arm insulator was used to conduct the lightning impulse test. Comparing with the electric field simulation results of the clean and contaminated insulators, the phenomenon of flashover along the surface of the insulator was analysed several times during the test. The tests and analysis indicate that in case of the SC-210 porcelain cross-arm installed with parallel gaps, its lightning impulse breakdown voltage U50% decreases with increasing salt density and tends to saturate more readily. The voltage-time characteristics curve of the lightning impulse of the contaminated insulator and the lightning protection gap gradually intersect, and the phenomenon of flashover along the surface of the insulator occurs several times during the test. The results of the study suggest that the effect of contamination on the flashover/breakdown location on the surface of the insulator should be considered in the insulation timing of the parallel gap and the insulator string.