冲击电压下特高压支柱绝缘子表面电场研究

特高压输变电工程对支柱绝缘子提出了更高的技术要求,运行中支柱绝缘子会因雷击发生污闪,而支柱绝缘子的电场、电位分布和闪络现象存在一定关系。为研究特高压支柱绝缘子表面电场分布特性,建立了1 100kV支柱绝缘子的有限元计算模型。理论分析与仿真结果表明,雷电冲击电压作用下支柱绝缘子表面电场分布随时间变化的曲线在波形上与激励源雷电波的波形相似,第一对和最后一对大小伞的电场强度较大,中间大小伞的电场强度较小,最大场强点位于金属电极下端的绝缘护套表面。

Research on the exterior electric field of the ultra-high voltage post insulator under impulse voltage

Higher technical requirements of post insulator for ultra-high voltage(UHV) transmission and transformation project have been proposed.The polluted post insulators on service may flashover as a result of lightning.The electrical field and potential distribution of the post insulator have relations with the flashover.In order to study the character of exterior electric field distribution in UHV post insulator,a finite element computation model is set up by theory analysis.The electric field distribution of 1 100 kV post insulator for substation operated in standard lightning impulse is computed.Research result can be achieved that the electric field distribution curve changed with time is similar to the excitation source of thunder.The electric field of the first and the last big or small umbrella is large,and the middle umbrella is relative small.The biggest electric field lies in the insulation jacket surface,which is a serious challenge for insulating medium.