Main generators produce electricity for the ship during normal operation.
Emergency generator produces electricity for the ship in the event of an emergency.
Main bus bar is a central electrical distribution point that connects the main generators, emergency generator, and emergency switchboard. The main bus bar supplies 440V directly, 220V via transformers and 24V DC via transformers and rectifiers
Emergency switchboard distributes electricity to the ship's emergency systems, such as navigation lights, communication equipment, and life support systems. Emergency generator is also connected to the emergency switch board.
Bus tie breaker is a switch that can connect the main bus bar to the emergency switchboard. This allows the emergency generator to power the ship's emergency systems in the event of a failure of the main generators. It is the devices that prevent two electrical sources from being connected to the same circuit at the same time. This helps to prevent electrical accidents.
Shore supply is a connection that allows the ship to receive electricity from a shore-based power source. This is often used when the ship is docked.
The general scheme of a ship’s electrical power system is common to nearly all ships. The below figure shows a typical electrical distribution system of a vessel.
In normal operation, the main generators are connected to the main bus bar and the main bus bar is connected to the emergency switchboard. This allows the main generators to power the ship's entire electrical system.
If there is a failure of the main generators, the bus tie breaker will automatically open, disconnecting the main bus bar from the emergency switchboard. The emergency generator will then start automatically and begin powering the ship's emergency systems.
The bus tie breaker interlock prevents the main generators and the emergency generator from being connected to the emergency switchboard at the same time. This helps to prevent electrical accidents.
Shore supply can be used to power the ship's electrical system when the ship is docked. To do this, the shore supply is connected to the main bus bar. The main generators are then turned off and the bus tie breaker is opened. This disconnects the main generators from the ship's electrical system.
The ship's electrical power system is designed to provide a secure and reliable supply of electricity to the ship and its crew.
