PERFORMANCE OF INSULATORS WITH DIFFERENT SURFACE POLLUTANTS UNDER HVDC CONDITIONS.

A systematic field and laboratory testing program was carried out to study the problem of the flashover of contaminated insulators under HVDC conditions. This study reports findings from the laboratory studies with emphasis on the performance of insulators with different surface contamination. It is found that a major factor that causes the degradation of the insulation strength is the accumulation of contaminants on the surface of an insulator after a prolonged period of exposure. To study such effects, one must first be able to quantify the pollutants, then artificially apply them onto insulators for laboratory study.