Estimation of the lightning strike incidence of free-standing masts

An efficient method is proposed in this paper for estimating the lightning strike incidence of free-standing masts. In the proposed method, the attractive volume is defined to describe the lightning attraction characteristic of the mast. Its border is determined from the interception condition of the upward leader to the downward leader. Introducing the modified formula allows the mast height dependency to be included in the evaluation of the striking distance. An integral is performed on the attractive surface to obtain the equivalent exposure area of the mast, with the stochastic distribution of approach angle of the downward leader taken into account. Then, the annual strike incidence is calculated for various mast heights. To confirm the validity of the proposed method, a comparison is made between calculated results and empirical formulas.