车顶绝缘子绝缘薄弱域的形成及影响因素研究

随着空气湿度及固体污秽等因素的影响,动车组车顶绝缘子表面存在的局部沿面放电会给列车运行安全造成严重威胁.依据有限元分析法,建立了25kV动车组车顶绝缘子流场及电场的三维模型,研究了高速气流、水珠及固体污秽对车顶绝缘子绝缘薄弱域形成的影响规律.结果表明:绝缘子表面气流速度较高、气压较低的侧风面及背风面区域容易发生局部沿面放电.当绝缘子表面附着雨滴和固体污秽后,表面电场发生了畸变,水珠周围局部电场强度增大;当水珠局部电场强度较大区域附着固体污秽时,水珠-污秽-空气-硅橡胶结合处形成新的绝缘薄弱域.

Research on formation and influence factors of weak insulation area of roof insulator

With effect of air humidity and solid pollution,partial surface discharge on roof insulator is a serious threat to the safety of electric multiple units(EMUs).According to theory of finite element analysis,three dimensional(3D) fluid field and electric field models of 25 kV roof insulator are set up.The effect of high speed air flow,droplets and contamination on weak insulation area of roof insulator is explored.Results show that discharge along insulator surface is more possible to occur on side surface and leeward area of insulator with higher flow velocity and lower air pressure at the high speed of EMUs.The electric field is distorted and partial electric field intensity around droplets rises after droplets and solid contamination are attached on the surface of insulator,making the bonded area of droplets,contamination,air and silicon rubber the new insulation weak area.