Surface charge accumulation on epoxy insulator installed in gas-insulated transmission line (GIL) and gas-insulated switchgear (GIS) has been recognized as a crucial factor for electric field distortion that results in the reduction of surface flashover voltage. This article reports on the gaseous ionization dependence of the charge accumulation pattern on a real-size epoxy insulator with multiarc surface profile by using various gas atmospheres. A coaxial electrode system was designed to investigate the charging behavior under dc voltages of -10, -20, and -30 kV. The insulator and electrodes were placed in a metal-enclosed test chamber, which was filled with 0.1 MPa air or 0.4 MPa SF6/N2 mixture to estimate the influence of the gas atmosphere on the charge accumulation behavior by a Kelvin-type probe. The accumulation mechanism and the electric field distortion induced by the charges were demonstrated based on numerical simulation. The results indicated that positive charges were accumulated in the shape of speckle on insulator surface in air, whereas both positive and negative charges were accumulated in SF6/N2 mixture and positive charge speckles appeared in SF6/N2 mixture only when the voltage raised up to -30 kV. It is considered that the charge accumulation behavior is determined by the competition result among the bulk, the gas and the surface conductions. As compared with the case in air, gaseous ionization in SF6/N2 mixture is more difficult to occur, which leads to the obvious difference in the charge accumulation pattern.

中文翻译：

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直流电压下复杂表面轮廓环氧绝缘体表面电荷模式的气态电离依赖性


气体绝缘输电线路（GIL）和气体绝缘开关设备（GIS）中安装的环氧树脂绝缘体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关键因素。本文报道了通过使用各种气体气氛，在具有多弧表面轮廓的真实尺寸环氧树脂绝缘体上电荷积累模式的气体电离依赖性。设计同轴电极系统来研究 -10、-20 和 -30 kV 直流电压下的充电行为。将绝缘体和电极放置在金属封闭的测试室中，其中充满0.1 MPa空气或0.4 MPa SF6/N2混合物，通过开尔文型探针评估气体气氛对电荷积累行为的影响。基于数值模拟论证了电荷的积累机制和引起的电场畸变。结果表明，空气中绝缘子表面正电荷以斑点状聚集，而SF6/N2混合物中正电荷和负电荷均聚集，并且只有当电压升高到-时，SF6/N2混合物中才出现正电荷斑点。 30 kV。认为电荷积累行为是由本体、气体和表面传导之间的竞争结果决定的。与空气中的情况相比，SF6/N2 混合物中的气体电离更难发生，这导致电荷积累模式的明显差异。