An investigation of salt contamination on insulators and the effectiveness of pin-type insulators with salt-proof dishes

Abstract

This paper investigates the contamination of the surface of various insulators suspended in the air at a certain altitude and connected in series. It is shown that salt-proof dishes attached to pin-type insulators are effective against contamination. Exposure tests of insulators on Okinawa have been made since 1985 and the results are as follows: 1 The higher the placement of the insulator, the heavier the contamination. 2 The amount of contamination on the downward surface of the suspended insulators at the lowest position was considerably smaller than that of the insulators at the other positions. 3 The extent of contamination of the pin-type insulators with the salt-proof dishes was far less in comparison to that of pin-type insulators without salt-proof dishes. 4 The maximum equivalent salt-deposit density was related closely to the small amount of precipitation during the observation period and the occurrence of high wind speed, which was higher than 10 m/s.