Shape Optimization of the Spacer of 220 kV DC GIL

Abstract

Both experimental and numerical studies demonstrate that electric field formation mechanisms and insulation behavior at SF6/epoxy interface are substantially different for ac and dc voltage excitations. In this paper, based on fixed dc GIL dimensions and spacer-electrode joints, three types of alumina filled epoxy resin spacers with different shapes were designed with FEA software in order to find a way to provide a reliable spacer performance in HVDC gas insulated systems. The generalized design criteria for dc spacers were put forward. Results show that shape design of spacer in dc GIL is distinct from that in ac GIL. Moreover, distinctions between dc spacer and ac one in shape design are proposed, which could be beneficial for practical use of dc GIL.