Grounding Strategies for High Voltage Shore Connection of Large Passenger Vessels

High voltage shore connection of large passenger vessels is an important way to improve energy efficiency and reduce local and global emissions, as well as noise. However, it is shown that the vessels' steel hulls will act as sacrificial anodes for the grounding systems in the ports, hence accelerated corrosion of the hulls may occur. The required protective earth (PE) conductor between the hull and the grounding system on shore could also introduce touch voltages above 30 V in case of a fault, posing a safety hazard. Based on field measurements and analyses, a grounding strategy with galvanic separation in the low resistance PE conductor is recommended. It is further advised to use active and passive cathodic protection, and to reduce the set point of the impressed current cathodic protection (ICCP) system to approximately 100 mV versus zinc. These measures will reduce the corrosion rate of the vessels' hulls during power delivery from shore, while avoiding transferred touch voltages.