Flashover Voltage Characteristics of Contaminated Bushing Shells for UHV Transmission Systems

This paper describes the power frequency withstand voltage test results of contaminated bushing shells for UHV transmission systems up to 15 m under fog condition. Described first are the facilities for testing such tall bushing shells of a large diameter. The test results show a linearity in relationship between effective length and withstand voltage both by the fog withstand method and the equivalent fog method. Assessment of 20 different shed shapes is made. The relation between average diameter and withstand voltage can be expressed in a quadratic curve.