Contribution to the analysis of wind turbine exposure to direct lightning strikes
Abstract
It is known that, based on the recommendations from IEC 61400-24:2010, the lightning protection of wind turbines (VA) is based on the assessment of the risk associated with lightning strikes (direct and indirect strikes to the VA and connection lines). The mentioned risk assessment, among other things, contains an estimate of the number of hazardous events (ie, lightning strikes) in the VA during a certain period of time (usually an annual level is taken). It is based on the so-called the electric shadow method and includes the so-called orographic (ambient) coefficient that should take into account the (increased) exposure of VA to direct lightning strikes (eg its position on top of a hill, etc.), as well as the consequence of the appearance of upward lightning strikes initiated by VA itself. Furthermore, IEC 61400-24:2010 also introduces the concept of effective height VA, but treats it in a rudimentary way. This paper will present a comparative analysis of VA exposure to direct lightning strikes based on the relevant IEC recommendation and treating the effective height of VA in a sophisticated manner.
