Grounding Strategies for High Voltage Shore Connection of Large Passenger Vessels

Abstract

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.

Cold Ironing Galvanic Corrosion Issues with Regard to a Shore-to-Ship Medium Voltage Connection

“…Interestingly the same electrochemical processes occur between the steel hull and quay [18] in the presence of electrolytes, During the cold ironing process, the electric shock hazard is increased by the presence of salty seawater and the decrease of the human body's total impedance (which drops to 1 kΩ in the presence of voltage exceeding 50 V). This is especially dangerous at the interface area between the concrete berth and the ship [16][17][18][19]. In the case of HVSC, IT connected systems equipped with neutral earthing resistors, for a shipside fault, the total impedance equals the equipotential wire PE impedance in parallel to the series of the two neutral point connected resistances.…”

Assessing High-Voltage Shore Connection Safety: An In-Depth Study of Grounding Practices in Shore Power Systems

“…The IEEE80005-1 standard and rated literature have discussed that, during faults, electric shock incidents occurring anywhere in the system due to direct or transferred voltages must be avoided. In addition, the touch or step voltage should be limited to not exceed 30 V. Furthermore, the limitation on single-phase ground fault currents must be further discussed regarding galvanic corrosion issues to ensure the integrity of the ship's structure [26][27][28][29][30].…”