Modeling by Nonuniform Transmission-Line Approach of Grounding Electrodes Under Lightning Currents

In this paper, we propose a modeling of the transient behavior of a grounding system. This modeling, in the frequency or time domain, is developed from the equations of non-uniform transmission lines (nuTL) and the numerical method of finite differences. The equations of non-uniform transmission lines will make it possible to introduce in the proposed mathematical model all the electromagnetic couplings which occur during the spatial discretization of the grounding composed of conductive wires and thus approach the full-wave modeling deduced from the Maxwell's equations. The frequency modeling that we propose makes it possible to consider the variation with the frequency of the electrical characteristics (resistivity and permittivity) of the ground and the temporal modeling to consider the ionization of the ground when the injected current is of very high intensity.