Flashover Tests at Project UHV on Salt-Contaminated Insulators, Part II

Results of experimental studies on the contamination flashover strength of EHV insulator strings are presented. The results compare favorably with a theoretical analysis by Boehne and Weiner in 1966-1967. Nonlinearity of insulation strength with insulator length has been investigated, employing a steam fog method to simulate natural humidity and fog. The nonlinearity is caused by nonuniform voltage distribution along contaminated insulator strings. Such nonuniform distribution is created by the capacitance of insulator units to ground. This relationship was clearly demonstrated by several indirect methods. The results should be very important in future contamination studies.