Influence of Grounding Resistance Connecting to Surge Arresters on Effectiveness of Lightning Protection Caused by Direct Hit for Power Distribution Lines

Abstract

The grounding resistance of surge arresters (Arrs) for the lightning protection of power distribution lines is generally maintained below 30Ω in Japan. Therefore, electric power companies have been spending a large amount of money on the construction and maintenance of low grounding resistances. In this paper, the influence of grounding resistance on lightning protection measures is clarified for power distribution lines with both a ground wire (GW) and Arrs by EMTP analysis and experiments. These results showed that even if the grounding resistance of Arrs becomes high, effectiveness of lightning protection is hardly decreased. Moreover, the results indicated that it is more important for constructing a rational lightning protection system to install a lot of lightning devices on power distribution lines than to lower the grounding resistance of Arrs.