Transmission Line Tower Grounding Performance in Non-Uniform Soil

Detailed computer analyses of a 765 kV typical transmission tower footing grounding performance during phase-to-ground fault condition are described and discussed. It is assumed the tower is erected on a two-layer earth structure. The tower resistance, worst touch and step potentials, are calculated for various soil conditions described by the top layer height and both layer resistivities. Universal charts are presented to help the engineer in predicting and designing transmission tower ground performance.