This paper is concerned with lightning surge propagation on wind turbines. As wind power generation undergoes rapid growth, lightning incidents involving wind turbines have come to be regarded as a serious problem. Nevertheless, no known studies exist yet in Portugal regarding lightning protection of wind turbines. Hence, we present a case study, based on a wind turbine with an interconnecting transformer, for the analysis of lightning surges. Computer simulations obtained by using the EMTP-RV code are presented. Conclusions are duly drawn.