Flashover Analysis for Medium-Voltage Line Considering Frequency and Current Dependent Grounding Resistance

Abstract:
The grounding resistance in the medium voltage line becomes low due to soil ionization caused by high current injecting into the grounding electrode. Thus, lightning current makes the grounding resistance low. Frequency dependence of soil resistivity and soil permittivity is another factor to be considered in lightning surge analysis. The author has proposed a simulation model to simultaneously consider the frequency and current dependence of the grounding resistance for lightning surge analysis. This paper discusses a flashover on an insulator of a medium voltage line considering the frequency and current dependence using the proposed model. This paper considers nonlinear phenomena such as the current dependence of a reinforced concrete pole and the flashover.