Effect of Overhead Ground Wires on Reduction of Failure Rates of Surge Arresters on Power Distribution Lines

Abstract

Surge arresters are sometimes damaged by lightning strokes with high energy, in spite of installation of a conventional protection method. In order to reduce the number of failure of surge arresters, we should consider another protection method, such as increase of withstand capability of surge arresters and installation of additional overhead ground wires. However quantitative comparison of these methods for preventing damages of surge arresters against lightning strokes with high energy has never been performed.
This paper describes effects of additional overhead ground wires for preventing damages of surge arresters. The main results are as follows:
(1) The failure rate of surge arresters on a distribution line with two overhead ground wires is about 3 times smaller than that with a overhead ground wire.
(2) Installation of the second overhead ground wire of 6_??_8 spans from the termination of a line is as effective to reduce the failure rate of a surge arrester at the termination as increasing of withstand capability by a factor of two.