Grounding effects of HV and MV underground cables associated with urban distribution substations

This paper derives a model for the evaluation of the performances of composite grounding systems of urban main distribution substations and associated cable networks. The effects of the cables upon the dangerous voltages, transferred potentials, and ground fault current distribution are encompassed including the conductive and magnetic coupling among grounding system elements, as well as the nonlinearity of cables sheaths impedances. An application example is presented and some experimental data.