Charge Regulation and Flashover Suppression by Surface Nonlinear Conductivity Spacer

Abstract

This study discusses the approach of adaptatively regulating the surface charge and electric field distributions by nonlinear conductivity materials. Three groups of surface nonlinear conductivity (SNC) spacers, namely SNC30, SNC60 and SNC90, were prepared by coating the epoxy/Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> spacers with epoxy/SiC composites of 30, 60 and 90 phr doping contents. Experimental results show impressive abilities of the SNC spacers on relaxing the electric field distortion by adaptively regulating the surface charge accumulation through nonlinear surface conduction. Under DC stress, the SNC spacers can significantly increase the discharge inception and the flashover voltages at room temperature. As the temperature gradient increases, the discharge suppression effects of the SNC spacers get weakened first and then enhanced. Surface charges on the SNC60 and the SNC90 spacers can make a rapid adjustment along with the polarity reversal voltage, the corresponding flashover voltages are improved by 18% and 29% compared with that of the original spacer.