Enhancing flashover performance of alumina/epoxy spacers by adaptive surface charge regulation using graded conductivity coating.

Surface flashover properties of alumina/epoxy spacers, involving a surface charge accumulation process, are critical for the safe and reliable operation of a high-voltage direct-current (HVDC) gas-insulated transmission line (GIL). This study reports surface charging behavior and flashover performance of alumina/epoxy spacers with different surface conductivity graded coating (SCGC) schemes in SF/N mixtures under DC stress. Four kinds of SCGC schemes, i.