Development of A Nonlinear Grounding Resistance Model for High Impulse Currents

Abstract

This paper carries experimental results of surge characteristics of a concrete pole, a buried conductor and a grounding net for high impulse current with the maximum magnitude of 40kA generated by an all-weather-type mobile impulse voltage generator. The experimental results show that the grounding resistance of the grounding electrode has a current-dependence and hysteresis characteristic.
Calculated results by a current-dependent grounding resistance model show a poor accuracy because it does not include the hysteresis effect. Based on the experimental results, a current- and energy-dependent grounding resistance model to describe the nonlinear surge characteristics has been developed. The model takes account of current dependency and hysteresis characteristics. Calculated results by the proposed model using the EMTP agree well with the experimental results. The proposed model is expected to be useful to an accurate simulation of a lightning surge.