Substation Surge Distribution During a Direct Lightning Strike

In this paper, a new model for calculating current and voltage distribution on the shield conductors of power substations during ligthning strikes reaching the physical installations is presented. The model is based on multiconductor transmission line theory. First, the electrical parameters of vertical and horizontal shield conductors are calculated, then modal analysis is used to obtain a two port network representation for all the shield conductors, considering both their direction and inter-conection. The model is solved using a simplified representation for the substation grounding grid. Finally, the model results are compared with those presented by other authors in the literature, with good results.