架空地線3条付500KV送電線のホーン間電圧のインパルス波応答測定とEMTP計算

抄録

The number of line ground faults by lightning on 500KV transmission lines has been reduced significantly during the past ten years. This is because the three-ground-wire system, which has been installed instead of the two-ground-wire system, plays an important role.
Where the ratio of voltage across the insulator horns in the two-ground-wire system was 1.0, the measured horn-to-horn voltage ratio was reduced to 0.40_??_0.64 by adapting the three-ground-wire system.
Measurement showed the voltage ratio became much smaller (0.33_??_0.57) after suspending a 77KV XLPE cable from the tower top to its foot, with the cable sheath connected at each tower arm.
These measured voltage ratios were in fairly good agreement with the calculated values obtained by the EMTP method.