Evaluation of Risk of Lightning Hits on Tall Structures in Japan

Abstract

Performance of wind turbines is much influenced by hazards associated with lightning hits. Damages of wind turbines by lightning hits in Japan show seasonal and regional variations, which may reflect characteristics of lightning hits on tall structures dependent on the season and the region. It was revealed that serious lightning faults of high voltage power transmission lines, experienced so far in winter along the coastal area of the Sea of Japan, were mostly due to upward lightning initiated from transmission towers. Wind turbines in the same region, reportedly suffer from a high lightning fault rate, must also generate frequent upward lightning, which is likely the cause of the frequent lightning damages. In this paper, it is proposed to apply the method to predict lightning performance of transmission lines, in winter in Hokuriku area, to evaluate frequency of upward lightning from tall structures in cold regions of Japan in winter. Moreover, the method to evaluate the risk of lightning hits on high structures in Japan through the year, in combination with the LLS data, is proposed.