Surface charge accumulation on epoxy insulator installed in gas insulated switchgear (GIS) or gas insulated transmission line (GIL) has been recognized as an important factor for electric field distortion that results in reduction of surface flashover voltage. This paper reports on surface charge accumulation behavior on a actual epoxy insulator for 100 kV GIL prototype with multi-arc surface profile. A coaxial electrode system is used to investigate the charging behavior under DC voltages with metal particles positioned at various positions of the surface so as to estimate its influence on the charge accumulation behavior using a Kelvin type probe. The results show that positive charges are accumulated mainly on the nonplanar region around the high voltage electrode in the shape of speckles, and the average charge distribution along the radial direction presented a double-peak feature. Moreover, the charge accumulation is enhanced by metal particles contacting to the grounded electrode. Using a numerical simulation method, it is suggested that the charge accumulation is mainly determined by gaseous ionization which is enhanced by the metal particle induced electric field distortion.

中文翻译：

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直流电压下金属颗粒促进多弧形环氧绝缘体表面电荷积累

安装在气体绝缘开关设备 (GIS) 或气体绝缘输电线路 (GIL) 中的环氧绝缘子上的表面电荷积累已被认为是导致表面闪络电压降低的电场畸变的重要因素。本文报告了具有多弧表面轮廓的 100 kV GIL 原型的实际环氧树脂绝缘体的表面电荷积累行为。同轴电极系统用于研究直流电压下金属颗粒位于表面不同位置的充电行为，以使用开尔文型探针估计其对电荷积累行为的影响。结果表明，正电荷主要以散斑状聚集在高压电极周围的非平面区域，沿径向的平均电荷分布呈现双峰特征。此外，接触接地电极的金属颗粒增强了电荷积累。使用数值模拟方法，表明电荷积累主要由气态电离决定，而气态电离是由金属颗粒引起的电场畸变增强的。