动车组车顶环氧树脂绝缘子合模缝对闪络路径的影响分析

Impact analysis of closing joint on flashover path of EMU roof epoxy resin insulator

动车组车顶环氧绝缘子在注射成型过程中,伞裙表面沿竖直方向会出现两条合模缝,凸起的棱边会畸变其附近的电场。本文对动车组车顶环氧绝缘子在湿润工况下合模缝对闪络路径的影响进行研究,通过喷淋闪络试验,比较合模缝处与伞裙其他部位的闪络概率,观察水滴在环氧树脂伞裙表面的运动特性,并通过仿真分析合模缝对水带形成、电场强度和电流密度分布的影响。结果表明:在合模缝处容易形成闪络通道,且在电场的作用下,合模缝附近的水带会拉伸甚至桥接相邻伞裙。高压端伞裙表面合模缝处水带的电流密度比伞裙其他部位的水滴电流密度高1倍以上;桥接伞裙的水带会畸变局部电场,缩小爬电距离和增加单位爬电距离承担的电压值。

In the process of injection molding of the epoxy insulator on EMU roof,there will be two closing joints on the surface of the umbrella skirt along the vertical direction,the convex edges will distort the electric field near it.In this paper,the influence of the closing joint on the flashover path of the epoxy insulator on EMU roof under wet conditions was studied.Through the spray flashover test,the flashover probability between the closing joint and other parts of the umbrella skirt was compared,the motion characteristics of water droplets on the surface of the epoxy resin umbrella skirt were observed,and the effects of the closing joint on the formation of water band,electric field intensity,and current density distribution were analyzed by simulation.The results show that the flashover channel is easily form at the closing joint,and under the action of electric field,the water band near the closing joint will stretch or even bridge the adjacent skirt.The current density of water band at the closing joint of high voltage end umbrella skirt is more than one time higher than that at other parts of the umbrella skirt.The water band bridging skirt will distort the local electric field,decrease the creepage distance and increase the voltage value borne by the unit creepage distance.