Evaluation of High Resistance Grounding in Medium Voltage Marine Systems

Grounding schemes play a significant role in maintaining the safety and operational efficiency onboard ships. The widely preferred grounding scheme is the floating neutral system due to the advantage of continual operation despite a fault in any of the phases. However, the transient voltages during the fault may result in multi-phase faults and eventually damage the complete system. The High Resistance Grounding (HRG) scheme resolves this problem while retaining all the benefits of an ungrounded system. The complexity in implementing the HRG scheme lies in choosing a resistor whose magnitude is less than the charging capacitance of the system. As per IEEE 45.4 −2018, the HRG scheme is recommended for LV systems only. To extend the benefits of HRG to MV systems, a comprehensive analysis with real-time data is necessary. In this paper, the performance of the HRG system for MV ship systems is evaluated, considering the specific challenges and design considerations unique to MV systems. The results of the HRG system are found satisfactory as the transients are not reflected when a high impedance fault is created.