Critical Distance for Line Breakage Prevention Capitalizing on Creeping Discharge Characteristics of Insulated Wires

Abstract

Although zinc oxide arresters are generally used on poles of distribution lines to prevent line breakage and minimize temporary failures caused by lightning strokes in Japan, installation cost has become a problem requiring solution with the increasing number of arresters.
A new line breakage prevention measure has been proposed which capitalizes on the characteristics of creeping discharge along overhead insulated power wires in order to promote cost reduction in lightning protection measures.
The results of a superimposition test with lightning impulse voltage and AC voltage indicate that if the puncture site on an insulation cover is at least at a critical distance from the line post insulator, line breakage may not arise because the creeping discharge between the puncture site and insulator would not result in an AC follow current which could vaporize the power wires.