Application of EP/SiC Coated Insulator in DC Gas-solid Insulation System

The non-uniform electric field (E-field) distribution is typically considered a key factor in triggering surface flashover inside gas insulated lines (GILs). To improve the surface E-field distribution along GIL insulators, this study proposed the concept of an interfacial E-field self-regulating (IER) insulator. In this paper, cone-type insulators were coated with epoxy (EP)/SiC composites to fabricate IER insulators. Next, an electrical simulation model was built to calculate the E-field distributions and energy losses of different insulators. As the coating thickness or SiC content increases, the E-field regulation function of the EP/SiC coated insulator becomes increasingly significant with increasing leakage current and energy loss. The DC flashover voltage of the EP/SiC coated insulator was found to be higher than that of the conventional insulator, with the flashover voltage increasing with the SiC content in the coating layer.