Abstract
Surge arresters and distribution equipments with zinc-oxide elements are used for lightning protection of overhead power distribution lines in Japan. However, these surge arresters are sometimes damaged by direct lightning strokes, especially in winter. Increasing of surge arrester failures in winter is attributed to a very large electric charge of winter lightning than that of summer lightning. For improvement of surge arresters, we have measured the energy absorption capability of surge arresters using a half cycle of alternating current with a frequency of 50Hz for simulating a winter lightning current. The mean values of arrester failure energy increased in proportion to the volume of zinc-oxide element, however the values of arrester failure energy were quite uneven. We also have observed the aspects of damaged zinc-oxide elements, and have investigated the relationship between the arrester failure energy and the failure types of zinc-oxide elements. From these results, we suggest the improvement of the energy absorption capability of distribution surge arresters, especially for the uniform energy absorption capability.
