Electric fields of grounding electrodes with frequency dependent soil parameters

The profile of the electric field developed at the ground level above a horizontal grounding electrode due to the impression to the electrode of waves resembling lightning currents of first and subsequent strokes was calculated using an electromagnetic model. The simulation considered both assumptions constant values for soil parameters resistivity and permittivity and frequency dependent values. This dependence was given by an expression derived from field measurements. It was found that the frequency dependence of soil parameters is relevant, mainly at low conductivity soils and short front-time current waves, leading to a significant decrease of the electric field profile.

► The electric field due to a current-carrying grounding electrode is calculated.
► The assumptions for soil are: frequency–dependent and –independent parameters.
► The two mentioned assumptions lead to quite different results.
► The effect of frequency-dependent parameters is stronger for high resistive soils.
► The effect of frequency-dependent parameters is stronger for subsequent strokes.