Insulator Selection for AC Overhead Lines With Respect to Contamination Working Group on Application and Inspection of Insulators

Insulator contamination remains an important tech- nical 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 contam- ination 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 signif- icantly, 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.