アークホーンから噴出するアークジェットによる66kV架空送電線の相間短絡を防止するアークホーン形状の検討

抄録

On a 66kV overhead transmission line equipped with the arcing horns interrupting the single-line-to-ground fault current (AHIFC), a two-phase short-circuit fault between an upper and a lower line caused by a lightning strike turned into a three-phase short-circuit fault. The authors have investigated the mechanism of the fault experimentally and clarified that the arc jets spouted upwards from the arcing horns of the lower line and the arc showed a tendency of rising easily due to the arc jets, then those caused the breakdown between the lower and the middle line, and the phase-to-phase short-circuit fault (PPSCF) occurred. In this paper, the authors investigated the PPSCF for the bird-damage prevention arcing horns which were installed in 66kV overhead transmission lines. As a result, the PPSCF tended to occur as the arc current increased and the upward wind velocity increased, which were different quantitatively from, but were similar as the results for the AHIFC. Considering the breakdown phenomena between the lower and the middle line, the investigations were carried out on the form of arcing horns for preventing the PPSCF. It was clarified that the PPSCF could be prevented by decreasing the upward angle and increasing the outward angle away from the steel tower of the both arcing horns on line side and steel tower side in order to move the arc jets spouting from the arcing horns and the hot gases generated by the arc jets in a horizontal direction.