Lightning current monitoring system for wind turbines

Lightning protection and surge protection measures are essential for the availability of wind turbines and for their profitability. Whereas the electric and electronic equipment can be protected by a comprehensive surge protection concept, outer structures particularly the rotor blades are hit by direct lightning strikes. In defined maintenance cycles these damages are inspected and repaired in costly operations. In this paper a method for lightning current measurement is presented. It enables the operator to measure lightning currents directly and to determine their parameters like amplitude, current rise time and charge. The presented system with three sensor units is originally developed for wind turbines, to adapt maintenance cycle times to the real number of lightning strikes. Further applications in other industries are possible.