Earthing effects of coated underground cables with metallic shields bonded to earth electrodes

Relatively simple expressions are derived for assessing the earthing effects of coated MV underground power cables with metallic shields (protective conductors) connected to source, and consumers´ transformer substations´ earth electrodes including the transferred potentials and touch and step voltages. The analysis performed for typical sample cases has shown that such cables might substantially affect the earthing system performances of the source substation and the associated distribution network and that, therefore, they have to be adequately taken into account for a rational and safe earthing system design