Challenges of Connecting Shipboard Marine Systems to Medium Voltage Shoreside Electrical Power

Ship service electrical power consumption at the pier side is rapidly growing and now exceeds 10-MW power range on many of the latest commercial ships. Short circuit current interruption capability of the switchgear and cables servicing the ship load at the port dictate the use of medium voltage power distribution systems at voltages from 5- to 21-kV range. Many of the high power medium voltage electrical loads must operate during unloading and loading of the docked ships. At the same time, environment protection regulations in many sea ports (California´s largest ports are examples of the most restrictive requirements) do not allow ships to operate their prime movers while at berth. Many ship operators and port authorities are struggling with the absence of appropriate standards and specifications for interconnecting the ship service loads to onshore power distribution systems. The intent of this paper is first to review the theory, practice, and existing interconnection standards and then to outline what can be done to achieve a secure, reliable, safe, and cost-effective operation of the ship service loads inside international ports. This paper will review the current state of cold ironing, existing applicable standards for ship interconnections to shore power, proven techniques for shore power interconnections, as well as approaches to mitigate challenges of high power and high voltage shore power