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PE, FIEEE, FACEC
Low-Voltage Shore Connection Power Systems
IEEE Industry Applications Magazine, September/October 2018
This article reviews low-voltage shore connection (LVSC) power systems for ships with up to 1,500 kVA and voltage of 400-690 V. The design concept for these systems is contained in the current LVSC draft standard, International Electrotechnical Commission (IEC)/IEEE 80005-3. Here, we attempt to clarify that an LVSC design concept using multiple parallel feeder circuit breakers does not violate National Electric Code (NEC) National Fire Protection Association (NFPA) 70 Section 240.8. We also attempt to clarify the optional design for an ungrounded shore power system, as required by certain ships and included in the draft standard. In addition, we review the safety loop circuit that enhances operator safety both onshore and onboard a ship.
Overview of LVSC Power Systems
Shore-to-ship power supply, also called alternative maritime power (AMP) or cold ironing, has been adopted around the globe to reduce, as much as practical, air pollution from ships , , . Smaller ships rated up to 1,500 kVA require an LV connection between the shore power substation and the ship switchboard, as described in the current draft standard, IEC /IEEE 80005-3. Each power plug and associated receptacle is rated at 500 A continuous and has a 16-kA short circuit rating and a voltage rating of 1,000 Vac. Therefore, for a ship load of more than 500 A, parallel feeders with plug and receptacle assembliesare necessary to meet shore power requirements. Up to five parallel feeders are needed for ships rated 1,500 kVA at 400 V.