Realistic modeling of the grounding system transient behavior with frequency dependence

Abstract

For better protection of electrical networks, modeling the transient behavior of grounding systems is now fundamental before the realization step. In this work we propose a new modeling approach which permits a quick and efficient analysis of the grounding systems.In the proposed approach we solve the transmission lines equations using the Finites Differences (FD) taking into account the different electromagnetic couplings that occur during the spatial discretization of the grounding electrodes. To achieve this objective we complete the general transmission lines equations by introducing the coupling terms between the different parts of the grounding system and we calculate the self and mutual per-unit length parameters according to the geometrical position of the elements (cells). We therefore use rather the term non-uniform Transmission Lines (nuTL). This new modeling offers the advantages of calculating in a single step the currents and voltages at all the points of a grounding system, also taking into account the frequency dependence. Compared to already existing full-wave electromagnetic models our modeling is realistic because its numerical implementation is simple, retains good precision and the calculation times are much reduced.