Surface morphology and chemical characteristics of GIS epoxy insulators under microsecond-pulse excitation

Summary form only given. Gas insulated switchgear (GIS) for power system becomes more and more compact and, thus, flashover phenomenon is more likely to occur on the surface of the support devices made of epoxy in the GIS, which is harm for the insulation and operation of the GIS device¹, ². In this paper, the flashover characteristics of the epoxy insulator under microsecond-pulse excitation are investigated. In the experiments, the epoxy insulator samples are placed in a sealed chamber filled with SF₆ or other mixed gas, and the flashover voltage and flashover time is measured. The morphology and elemental composition of the surface of the samples before and after the flashover are analyzed by atomic force microscopy (AFM), 3D digital microscope and X-ray photoelectron spectroscopy (XPS). The experimental results show that the surface morphology (roughness) is closely related to the insulation strength of the epoxy surface, and the surface elemental composition is related to the insulator´s electrification level. The results will make a good reference for improving the surface flashover voltage of the epoxy insulators in the GIS device.