Natural Contamination test of Insulators at Noto Testing Station Near Japan Sea

This paper describes the results of investigation into the performance of various types of insulators energized with 200 kV ac and ±280 kV dc voltages and exposed to natural conditions by the seaside for about five years. DC voltage application had almost the same influence on the salt deposit density as ac voltage application. Salt deposit density and flashover characteristics of insulators were much affected by their types. Flashover voltage for dc is almost the same as that for ac in rms value.