Fractal simulation of soil breakdown under lightning current

A stochastic probability model based on fractal theory is first introduced to simulate and analyze the initiation and propagation processes of the actual discharge in soil under lightning current in this paper. The influences of the length of grounding electrodes, the critical field gradient of soil breakdown and the soil resistivity on the processes of soil breakdown are discussed. And the conception of impulse effective length of grounding electrodes under impulse current is explained.