Lightning strikes to towers: An attempt to identify the effect of the channel resistance on wave interactions at the return-stroke front

Abstract

This paper presents an attempt to identify the influence of the channel resistance on return-stroke current propagation resulting from a lightning strike to a tall object such as a metallic tower. For simplicity, the tall object and the lightning channel are represented as uniform transmission lines. The former is modeled as a lossless transmission line, while a nonlinear resistance is considered in the latter. Two cases are considered for different values of channel conductivity. In the first case a series voltage source is used to excite the interface between the tower and the channel assuming that the characteristic impedances of both are matched. The second case assumes unmatched characteristic impedances. The role of the per-unit-length resistance on the currents calculated in both cases is investigated. This is made to study its effect on wave interactions that take place at the return-stroke front.