Insulator Selection for AC Overhead Lines With Respect to Contamination

Insulator contamination remains an important technical problem because contamination-caused insulator flashovers may jeopardize the security of high voltage power systems. This paper updates an insulator selection guide with respect to contamination first published 25 years ago. As in that guide, this update relates primarily to contamination conditions in North America. Results of research that have led to a better understanding of contamination-caused flashovers, particularly for some types of nonceramic insulators are summarized. Assessment techniques for site severity are discussed. Even though they have improved significantly, no leading method has emerged. Artificial contamination test methods have been standardized. Mitigation techniques are discussed for extreme contamination-caused dangers, including important new knowledge regarding ice and snow flashover voltage reduction. caused.