Step Voltage Calculation Above the Horizontal Grounding Electrode

The paper deals with the step voltage calculation for the case of the simple grounding system (horizontal grounding electrode) injected with the fault current. Analysis is based on the thin wire antenna theory and corresponding frequency domain Pocklington integro-differential equation. The influence of a ground-air interface is taken into account via the Fresnel reflection coefficient (RC). The Pocklington integral equation is solved by the Galerkin Bubnov indirect boundary element procedure. After the current distribution along the grounding wire is calculated, electric potential at an arbitrary point on the ground surface is readily obtained by integrating the normal field component from infinity to the observation point. Step voltage is calculated as the voltage difference between two points 0.5 m to 1 m apart (average separation between human feet) along and perpendicular to the grounding electrode. Furthermore, step voltage is also calculated over the whole area in the vicinity of the grounding system taking into account direction of the steepest change of the potential and thus the worst case scenario.