Modeling of Conductors Catenary in Power Lines: Effects on the Surge Propagation Due to Direct and Indirect Lightning

In this article, the effects of the variable height in overhead power lines are investigated with reference to the surges produced by direct and indirect lightning events. Simulations are carried out both by an implicit finite-difference time-domain scheme and by the commercial tool EMTP-RV. Differences in the waveforms computed by the two approaches are discussed and clarified. Additionally, the validity of the commonly adopted assumption of weakly varying vertical component of the incident electric field is investigated.