GIS支撑绝缘子表面状况对其雷电冲击闪络特性的影响

Influence of Surface Conditions on Flashover Characteristics of Supporting Insulators in GIS Under Lightning Impulse

SF6气体绝缘开关设备(GIS)的运行经验表明,绝缘子往往是系统绝缘最薄弱环节和决定性因素,因此研究绝缘子闪络特性的影响因素具有十分重要的意义。文中通过搭建1 000 kV陡前沿冲击试验装置,研究了雷电冲击作用下GIS内部支撑绝缘子表面状况对其闪络特性的影响。结果表明:绝缘子沿面闪络电压随表面粗糙度的增大而降低,文中从绝缘子表面吸附能力的角度对其进行了分析;绝缘子表面附着导电微粒时其闪络电压显著降低,且导电微粒距高压电极越近,绝缘子闪络电压越低,可从导电微粒附着位置对绝缘子沿面电场分布的影响上进行解释。

The operating experience of SF6 gas insulated switchgear （GIS） shows that insulators are often the weak link and key factor of system＇s insulation. Therefore it＇s important to find out factors influencing flashover charac- teristics of insulators. Based on a steep-front impulse test device, this paper presents our study about the influence of surface conditions along insulators on their flashover characteristics. The results show that increasing the surface roughness would decrease the flashover voltage of insulators, and this phenomenon is analyzed from the perspective of surface absorption ability of insulators. Flashover voltage drops obviously when conductive particle is attached to insulator surface, and the closer the particle is to the high-voltage electrode, the lower flashover voltage becomes, which is due to the change of electric filed along insulator surface brought by the change of particle position.