Damage of nonceramic insulator end fittings by power arc currents

The damage to weathersheds of nonceramic insulators caused by fault current flowing during a flashover may not be significant for subsequent operation of the transmission line. However, the fault current may result in reduction of the insulator´s mechanical strength and possible line dropping. Due to the concerns of a major electric utility user of nonceramic insulators, the effects of fault current on the strength of nonceramic insulators were investigated by power arc tests conducted in a laboratory. This testing focused on the effect of fault currents on the galvanized layer, the effect on the compression end fitting strength and the special case of high contact resistance caused by corroded end fittings.