High Resistance Grounding Systems in MV Shipboard Power Systems

Ungrounded neutral system is widely used as it offers the advantage of continuity in power supply even if one of the phases experiences a ground fault. However, with the increasing complexity of ship power system and induction of newer technologies, the ungrounded system may not be a viable option in futuristic systems. The solidly grounding system though restricts the over voltages in the system, it is not preferred due to the high fault ground currents. High Resistance grounding (HRG) restricts the amount of fault current to a negligible value and has the benefits of both ungrounded and solidly grounded system. In this paper, the performance of all the three grounding schemes is studied with a focus on HRG scheme for a medium voltage ship power system using MATLAB. The ship power system architecture is also discussed in detail.