Evaluating hazards of lightning strike on stationary vehicles under overhead lines

Abstract

This article examines safety concerns concerning persons touching a vehicle located near an overhead line hit by lightning. Two models of lightning strikes are assumed for the analysis. The first model includes the entire lightning channel and current distribution along the channel while the second model is a short channel of surge current injected directly at the top of the struck tower. In order to evaluate the effects of the lightning model on the shock hazard level, the transient current passing through the body of a person touching the vehicle is evaluated and compared to the case of a person touching directly the struck tower. An integral formulation of Maxwell's equations is used to model the whole structure including the vehicle, power line, towers, grounding network, and lightning channel. The vehicle is modeled as an array of metallic plates, while the remainder of the system is modeled as an array of wire mesh conductors. Computations are carried out using the Method of Moments (MoM) for surface-wire integral equation in a stratified medium. Results show that safety is affected more by the indirect radiation and induction effects of the lightning channel for the case of a person touching the vehicle than for the case of a person touching the struck tower.