Typical power system architecture for a large cruise ship with integrated
electrical propulsion.
The main generators power the propulsion motors and all service loads from one main bus. The industry standards require emergency power in all cruise ships.
The emergency power distribution should have three buses as shown at the top. The temporary emergency power comes from the battery or UPS, which is then automatically transferred to the final emergency generator bus when it acquires the rated voltage at rated frequency.

The kW power and the main power reliability and availability requirements dictated by the industry standards require additional features in the shipboard power system. The following architecture incorporates these features often found in today’s ships.