真空中典型沿面绝缘结构的电场分析

在高电压作用下,由复合绝缘介质构成的沿面绝缘结构的耐电强度远低于其绝缘材料自身的击穿场强,这一现象与其电场的分布特点密切相关。笔者针对真空中平行平板、平面和棒-板电极系统等多种典型沿面绝缘结构的电场分布进行了仿真计算,探讨了电极-介质结合处的间隙、圆台形绝缘子的圆锥角角度、平面电极的高度以及绝缘子介电常数等因素对电场分布的影响。仿真结果表明,接触间隙的存在导致局部电场的加强和电场方向的变化,间隙宽度越大、高度越小,间隙处电场畸变越大;圆锥角越大,绝缘子的介电常数越大,场强畸变也越大。该分析结果有利于真空中沿面绝缘结构的设计。

Electric Field Analysis of Typical Surface Insulation Configurations in Vacuum

Under high voltage stress,the electric strength of surface insulation system configured with compound dielectrics is far lower than the breakdown strength of its insulating material,which is closely related to its electric field distribution.The electric field distributions of typical surface insulation structures in vacuum was simulated,such as the parallel flat plate,planar and stick-plate electrode systems.Such influential factors were considered as the gap of electrode-dielectric contact,the coning angle of circular truncated cone,the height of planar electrode,and the dielectric constant of insulator,etc.The simulation results reveal that the contact gap results in the enhancement of local electric field and the change of its direction,more serious distortion of electric field will occur with larger contact gap,conical angle and dielectric constant or smaller electrode hieight.This conclusion will be helpful to the design of surface insulation structure in vacuum.