Electric Power Distribution System on Ships (Marine Electricity)

Th ship’s pow distribution system consists of different components for distribution and safe operation of the system. The main components of this system are:

1. Ship’s generator - consists of prime mover and alternator.
2. Main switchboard - a metal enclosure taking power from the diesel generator and supplying it to different machinery systems,
3. Bus bars, acts as power carrier and allows transfer of load from one point to another.
4. Circuit breakers - act as a switch, and in unsafe conditions can be tripped to avoid breakdown and accidents.
5. Fuses - safety devices for machinery.
6. Transformers, to step up or step-down the voltage. When supply is to be given to the lighting system, a step down transformer is used in the distribution system.

In a power distribution system, the voltage at which the ship’s electrical system works is usually 440v. However, there are some large installations wherein the voltage is as high as 6600 volts. Power on ships is supplied through circuit breakers to large auxiliary machinery at high voltage. For smaller supply fuse and miniature circuit breakers are used. The power distribution system, consisting of three wires, can be neutrally insulated or earthed. Insulated system is more preferred as compare to earthed system, as during an earth fault essential machinery such as steering gear can be lost.