Soil ionization in earth electrodes by a finite difference time domain scheme

This paper proposes a finite difference time domain numerical scheme devoted to analyze the transient behavior of earth electrodes during the soil breakdown that can take place when a surge current has to be drained. To this aim, Maxwell´s equations together with a space-time variable resistivity function are used. The model has been validated by comparing the computed results with data available in the technical literature. Simulation results related to complex earth electrodes of limited extension are reported. Electrodes of larger extension can be easily simulated but requiring more computational resources.