A Two-Layer Soil Model for the Calculation of Electrical Parameters of Grounding Systems under Lightning Strikes

This article aims to overcome the drawback of the consideration a uniform soil model in approaches based on the transmission line model by considering a two-layer soil structure. In this regard, the electrical parameters equations for the two-layer soil model based on the method of images in the literature which are suitable for power frequency waves are developed to be applicable to the lightning studies. Also, the developed equations are then used in the multiconductor transmission line approach to study the lightning behaviors of grounding systems. Furthermore, in order to check the validity of the procedure, the results of the multiconductor transmission line approach are compared with those obtained by the electromagnetic field approach through the simulation of horizontal, vertical and mesh grounding grids. The results show the accuracy of the two-layer soil model for the lightning analysis of grounding systems.