500 KV station-post insulator performance at P G and E´s outdoor laboratory at moss landing

This paper discusses a three-and-one-half-year study of constantly energized 500 kV station-post insulator performance in a coastal environment where ocean salt, moderate industrial contaminant, and coastal fog are encountered. Under test at PG and E´s Moss Landing EHV Laboratory are semiconductive, siliconed, and untreated porcelain glazed posts. Semiconductive and full length siliconed posts have not flashed over during the test period. Multiple flashovers of the untreated posts in nighttime fog have required summer hotwashing to allow continued testing.