中文摘要：

潮湿天气环境中，凝集在车顶绝缘子表面的水珠会畸变电场，引发电晕放电，影响列车运行安全。文中针对车顶受电弓支撑绝缘子建立有限元仿真模型，分析了水滴位置、大小、数量等参数对绝缘子沿面电场的影响，并将常用于高电压等级输电线路中的均压环配置原理运用到电压等级较低的车顶绝缘子中，以抑制水珠诱发的电晕放电。结论表明：护套与伞裙连接处水珠对电场畸变最严重；伞裙上半径r=2mm的水珠对电场畸变影响最严重；水珠间距越大，沿面平均场强越小。确定了均压环环径R=85mm，管径d=24mm，屏蔽深度H=50mm的均压环最佳配置方案。

英文摘要：

Under humid condition,water droplets on the surface of roof insulator will lead electric filed distortion, and induce corona discharge,which is a threat to train operation. A roof insulator computational model is estab- lished based on finite element method to simulate the influence of water droplet parameters, like position, size and amount, on electric filed distribution along insulator surface. And grading ring frequently used on insulator for high voltage transmission line is applied to roof insulator,to suppress corona discharge induced by water droplet. The result shows,water droplet at the junction of shed and sheath has the greatest impact on electric field distortion. When the radius of water droplet is 2 mm, influence of water droplet on shed is most obvious. A larger distance between water droplets results in weaker maximum electric field along insulator surface. The optimal configuration scheme of grading ring is confirmed that radius is 85 mm,the section radius of grading ring is 24 mm,and the height apart