Effect of the shape of the solid insulators on creeping discharge propagation under AC voltages

Abstract

This paper studies the use of circular and square shaped solid insulators on creeping discharge propagation over solid/liquid dielectric interfaces under AC voltages. A point-plane electrode arrangement based test apparatus is used to initiate creeping discharges over solid/liquid interfaces and the discharge propagation is captured using a camera. Two shapes of solid material samples are used to analyze the effect of using different shaped dielectric samples for the creeping propagation under AC voltages. Two types of solid materials, glass and acrylic, immersed in copra coconut oil are tested. Discharge length of the discharge patterns and the fractal dimension calculated by box counting method are used to explain the effect of square shaped and circular shaped dielectric samples for the morphology of creeping discharges. Results show that the shape of the solid dielectric material does not have a significant effect on the discharge length, fractal dimension and the shape of the discharge pattern.