A hybrid frequency-time domain methodology for the modeling of grounding systems

This paper presents a numerical modeling, combined the finite element method in frequency domain with the finite difference time domain, to calculate the transient impulse characteristic of grounding systems including the ionization phenomenon. In this numerical method, space-time variable soil resistivity is used to simulate the soil ionization phenomenon and no a priori hypothesis on the geometrical shape of the ionized region around the electrodes is necessary. The proposed numerical scheme is validated by comparing computed results with experimental results in literature.