Surface Dielectric Behavior of Polymeric Insulation under HV Outdoor Conditions

This paper is a review of surface dielectric behavior of several polymers under HV outdoor conditions. The scope of this review is limited to materials used to provide weathersheds on non-ceramic insulators and room temperature vulcanized silicone rubber coating used on ceramic insulators for combating problems related to insulator contamination. The paper is divided into three parts: Part 1 includes a brief history and philosophy which led to the development of present day materials and test methods. Part 2 deals with the dynamic nature of polymer surfaces which plays a vital role in service. In Part 3, key issues regarding dielectric properties that relate to outdoor insulator performance are put forth, and developments in the fundamental understanding of some of these issues are discussed. The paper includes an extensive list of publications on the subject.