Presentations

Abstract

We present a work on characterizing the lightning activity in two onshore wind farms and the physical parameters of the lightning strikes measured by a Class I Lightning Measurement System in the wind turbines according to IEC 61400-24 Ed. 2 Amendment 1 (CDV). The seasonal distribution of the lightning activity at this location in mid-latitudes is investigated, focusing on the lightning strikes to the wind turbine blades. The climate area in which these wind farms are located suggests a distribution biased towards a more intense lightning activity in the warm season. However, the presence of the wind turbines increases the lightning activity monitored during the cold season when the weather conditions lead to a very close gap between the blades and the clouds. The physical parameters measured of each lightning strike in the different seasons focus on the polarity and peak of the current, specific energy, charge, and steepness of the current waveform. Besides, each lightning strike is classified into upward or downward after an accurate processing of the current waveform. The physical parameters obtained are compared to the distribution provided by the lightning protection standard (IEC 61400-24 Ed.2) and the deviations from these standard distributions are highlighted. The work provides a new insight into the lightning exposure of wind turbines and how the overall lightning activity of an area is affected by the presence of tall structures. A relevant outcome of this study is a better understanding of the lightning protection system wear due to direct strikes to the blades.