Investigation of Lightning Damages on Distribution Lines

Lightning damage on 3.3-and 6.6-kV overhead distribution lines is investigated. The damaged apparatus and its components are distributed on the line in the vicinity of lightning stroke point. Induced lightning surges are very dangerous at the line ends and they attack the poles branching the line harder than the neighboring poles. It is considered that blowing of primary fuses for distribution transformers is often caused by power short circuits formed by flashover of induced lightning surges on the bushings when lightning strikes close to the line. The appearance of lightning damage suggests that hitherto accepted mechanism of induced lightning surges should be re-examined. Also the actual results show that protective effect of overhead ground wire on induced lightning surges is considerably high.