Observational and experimental study of the lightning stroke attraction effect with ground wire system constructions

Although power distribution lines are protected by ground wire systems, there are fears that these ground wires may break at their corrosion points. For practical purposes, they have therefore been removed to avoid maintenance in certain areas. The Tokyo Electric Power Company (TEPCO) has continuously observed lightning strokes and obtained 321 datasets to date. The present study has determined the potential for an anticipated lightning stroke attraction effect based on the observed data, despite the fact ground wires are eliminated while ground wire caps are left in place. Furthermore, a verification experiment using facilities simulating the power distribution system has confirmed the problem of insulated wires being struck by lightning and the extent of the impact of the ground wire cap on the lightning stroke attraction effect. These results are expected to provide a new facility-construction menu, which will help rationalize the lightning protection design.