On the lightning incidence to wind farms

Abstract

Lightning strikes are a common cause of damage to wind turbine blades. This paper intends to discuss the lightning incidence to wind turbine parks considering both downward and upward lightning discharges. The analysis is based on numerical simulations performed with the Self-consistent Leader Inception and Propagation Model SLIM. It is found that the calculated annual frequency of strikes due to downward lightning is several orders of magnitude smaller than field observations in the Horns Reef 1 wind park. This shows that upward lightning discharges should be considered in order to obtain proper estimates of the lightning incidence to wind turbines. Thus, it is also found that the thundercloud electric field required to trigger upward lightning from wind turbines depends on whether the discharge is self-triggered or nearby-lightning triggered. A discussion about the existing limitations to estimate the upward lightning incidence in wind parks is presented.