Quantification of the probability of lightning strikes to structures using a fractal approach

Recently fractal theory has been used to model the observed paths of lightning discharges. This paper extends previous work by using a fractal approach to describe the effects of tortuosity and branching of the lightning channel. In particular, we use the model to make predictions of the probability of lightning strikes to practical structures. Some of the specific estimates include the probability of strikes as a function of interception angle, predictions of the strike points on structures, and the probability of "side strikes" to tall structures. Significant polarity and geometric effects are shown. The shielding effects of nearby taller structures, shielding failure or "breakthrough" probabilities of so-called protected objects, and the effects of ground topography are also examined. The results are discussed in terms of the implications for the protection of structures against lightning.