Influence of Lightning Strike on Availability of Wind Turbine and its Damage Analysis

There are usually no high structures that block the wind around a wind turbine. Therefore, wind turbines are often struck by lightning. From such a background, “Interpretation of technical standards for wind power generation systems” was revised in Japan, it was obligatory to stop the operation of the wind turbine with an emergency stop system and to restart the operation after confirming the soundness when a lightning detection system installed on the wind turbine detects a lightning strike. But it may take time to restart because sometimes it is difficult to visit the wind turbine for immediate inspection after stopping. In this paper, we investigated the influence of lightning strikes to wind turbines on the availability. In order to consider countermeasures to improve the availability, it is necessary to understand lightning damage situations of the wind turbine. According to the periodic safety management review system in Japan, blade inspection data and maintenance data of each wind turbine had to be recorded. Based on these data, we also report the relationship between lightning damage and lightning parameters.