Comparison on ac icing flashover performance of porcelain, glass, and composite insulators

Abstract

The electrical performance of insulators under the comprehensive conditions of low air pressure, pollution and icing, is an important basis for the selection of external insulation of transmission lines and substations in icing regions. However, little research has been dedicated to the comparison on ac icing flashover performance of composite, porcelain and glass insulators in this environment. Based on the investigations carried out in the artificial climate chamber on three types of iced insulators, the ac flashover performances of insulators were researched in this paper. In addition, the paper analyzed and compared the effects of various factors, including ice thickness, pollution and air pressure on the flashover performance of three types of iced insulators. The experimental results show that the flashover voltage of three types of insulators decreased with the increase of ice thickness, pollution, and the altitude. The characteristic exponent characterizing the influence of the ice thickness, pollution and atmospheric pressure on the flashover voltage were related with the insulator types. The effect of ice thickness and atmospheric pressure on icing flashover voltage was more apparent for composite insulator than porcelain and glass insulator. The characteristic exponent characterizing the influence of pollution on the flashover voltage was small for composite insulators. Under the same condition, the flashover voltage gradients of ice-covered composite insulators are slightly greater than porcelain and glass insulators.