抄録
The lightning damage on low voltage distribution systems is almost burning of low voltage distribution equipment due to flashover and are dynamic current. The lightning overvoltage causes flashover of low voltage distribution equipment. After that, the flashover causes burning, because of the impression of the commercial frequency voltage. So far, the authors have clarified this lightning damage mechanism experimentally. According to these experiments, it was proved that which equipment in a low voltage distribution line suffered the lightning damage. And, it was also proved that restricting the lightning damage position in a low voltage distribution line was possible analytically by using the EMTP. In this paper, the method for calculating the lightning damage ratio of low voltage distribution equipment is described. To begin with, the relationship between lightning damage position in a low voltage distribution line and lightning stroke current value is calculated according to the current value divided small. Next, each lightning stroke current level is compared with cumulative frequency distribution of peak return-stroke currents, electricity geometric striking distance model, etc.. And finally, the lightning damage ratio is calculated. Using this method, the lightning damage ratio was calculated for several lightning protection in low voltage distribution system, and each effect was quantitatively verified.
