Practical tables for the design of the grounding systems in distribution networks in presence of metallic interconnection

The present paper deals with the dependence of the ground current, due to a single-line-to-ground fault in a secondary substation, on the electrical and geometrical parameters of a Medium Voltage distribution network in which a metallic interconnection between the grounding systems is realized. Examining different situations, some easy-to-use tables are provided for a practical approach to the design of the ground electrodes of the secondary substations in these networks. The relevance of the work is due to the lack in the international standards of specific indications on how to consider the presence of the interconnection elements in distribution networks.