The analysis of grounding system under lightning surge currents

A simulation model based on finite-element method is presented to analyze the soil ionization phenomenon around the grounding system under the impulse current. In this method, The non-linear characteristic of soil under an accidental short circuit or a stroke of lightning is taken into account by setting the resistivity of soil element varying with the electric field intensity of every element; open boundaries of earth environment are processed by introducing a spatial transformation. Meanwhile, the simulation impulse experiments are carried out on a real small grounding system. The suggested modeling is validated by compare the calculated results with experimental tests results and simulations results found in literature.