Lightning protection of wind turbines - a comparison of measured data with required protection levels

Latest wind turbine lightning protection systems have been refined to the point where lightning damage is now relatively rare. This is increasingly important as wind turbines move offshore where access for maintenance is more difficult than for most land-based wind farms. Manufacturers have been trying to make sure that the lightning protection systems they install comply with the highest protection levels stipulated in the relevant IEC standards. In this study, data from the Nysted Offshore Wind farm in Denmark and that from a large number of other wind turbines worldwide is reviewed to show the range of lightning currents that have been measured on wind turbines currently in operation. These current values are compared with the required protection levels within the standards.