Performance of Line Insulators Under Rime Ice

Single suspension insulator units of several types as well as multi-unit strings were studied in a large refrigerated chamber. Rime ice of various densities was deposited on these insulators. The increase of leakage currents, the reduction of flashover voltages, and the alteration of voltage distributions along insulator strings caused by the presence of the ice were measured. The effects of various protective coatings on the insulator performance were examined. The process of insulator flashover under rime ice is compared with that under the usual types of industrial and marine pollution at temperatures above freezing point.