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

The design and the realization of the grounding system of urban areas MV/LV substations, it's often a complicated and onerous task, considering the high values of the ground fault currents usually present. A measure to reduce the design currents of the grounding systems consists in connecting together all the ground electrodes, using the metal sheath of the MV cable lines. The present paper provides some easy-to-use tables for a practical approach to the design of the ground electrodes of the secondary substations in those distribution networks in which a metallic interconnection between the grounding systems is realized. The relevance of the work is due to the lack in the international standards of specific indications on how consider the presence of the interconnection elements in distribution networks.