Electrical safety in MV industrial power systems. An innovative solution with compensated neutral

This paper addresses the ground faults protection issues in the closed-loop operation of MV industrial power systems, analyzing how neutral grounding status can affect the protection system operation. In particular, besides the widely established practice in industrial plants (i.e. low-resistance grounding), in this paper an alternative neutral grounding solution is proposed, which consists in the operation with compensated neutral (Petersen coil-resistor combination). The implementation of pilot relaying schemes (PRS); supporting zero-sequence wattmetric directional relays, is evaluated in order to ensure selectivity of protection systems and improve fault clearance times.