The purpose of transmission line grounding is to provide adequate lightning performance of the line; and effectively dissipate fault current avoiding the build-up of unsafe step and touch potentials around the tower base.

The effects of lightning strikes on earthing or protection systems designed to IEC 62305 can be modelled using an equivalent single frequency from 25kHz up to 1MHz which gives similar results to a time-domain approach. This article provides the frequency and current values to be used for modelling lightning.

Reach touch voltages are different to touch voltages and automatically set to zero when the distance between the voltage point on the ground surface and the grid conductor which is touched exceeds a reach distance.

Copper is often preferred for its superior electrical properties, while aluminum and galvanized steel are chosen for cost-effectiveness. Copper-clad steel can offer a balance between cost and performance. This article demonstrates which option is best for different scenarios.