抄録
There is a possibility that satisfactory protective effects for a three-phase power distribution line are attained even if it has surge arresters on only two phases. In order to evaluate the lightning protection effects, experiments of direct lightning strokes and analysis using the EMTP were done.
Lightning protection effects were quantitatively clarified by experiments of direct lightning strokes on simulated full-scale power distribution line with surge arresters on two phases.
Analytical results, which were got by taking the reducing effect of grounding resistance into account, agree well with experimental results. If the value of grounding resistance is less than 30 ohm, the power distribution line with surge arresters on two phases did not suffer from any flashover against the direct lightning stroke with a peak current of-40kA.
