Damage Threshold of Surge Arrester Depending on Configuration of Power Distribution Line

The authors investigated the probability of surge arrester burnout accidents for the various configurations of power distribution lines. Specifically, the authors calculated damage threshold of surge arresters in case of lightning strike to the center of LIL(a straight distribution line of infinite length), near the branch pole of LWB (a distribution line with a branch point), or near the termination of LWT (a straight distribution line with a termination point), based on numerical calculation by XTAP (expendable transient analysis program). If there is an overhead ground wire on a distribution line, damage threshold of surge arresters on the LWB and on the LWT is influenced by the branch position in relation to the lightning striking pole as well as the wave tail duration of lightning current. If there is no overhead ground wire, damage threshold of surge arresters is almost the same regardless of the line configuration and position of lightning strike. All above results can be explained easily by the equivalent circuit developed in this paper.