Dummies Guide to Emergency Power System on Ships

You have read about a few basics of marine electrical systems including generators, motors and switchboards. As you now find yourself enlightened with the brief gist of the crucial elements of the ship’s electrical system, you decide to take a quick coffee break and munch on a bar of snickers, simultaneously trying to recollect and imbibe whatever you have learnt so far:

The generator is the heart of the ship. To control and use the generator we use motors, motor controls and main switch boards.

Now, these elements constitute the basic requirement of the electrical system of any kind of ship. But that doesn’t mean that the ship can run solely on them. There are few other elements and parameters that need to be taken into consideration for the continuous supply of electrical power and also to ensure safety and redundancy. Let’s learn a bit more about them.

The main intention of an emergency power system is to furnish immediate, automatic electric power to a limited number of selected vital circuits. The emergency power system includes one or more diesel-driven emergency generators (which we will learn a bit more on later) as well as an emergency switch board and a distributed system. Both emergency generator and emergency switch board are kept above the waterline to minimize danger from flooding. Emergency services also include the navigation, safety and emergency lights.

All these emergency services should be supplied from the emergency switch board. An emergency switch board has distributed panels for all the emergency services onboard. The emergency switch board as we discussed earlier is always located above the bulkhead deck. This is to ensure that at the time of any emergency such as fire or flooding, the switchboard is not affected and is easily accessible and that any such emergency does not lead to loss of lighting in escape routes and other important navigation control areas.

Thus as of now, the main components of an emergency power system are a generator and switch board.

The ship’s emergency electrical system and the safety of the ship and the crew are interwoven. You can say that the electrical emergency services, also known as the “emergency power system”, is the back-bone of safety on the ship.

The arrangement and the installation of the emergency services should be so smartly done that no matter what happens to the ship the emergency system should provide energy and support lives on ship until the situation can be handled.

Firstly, let us find out what does it mean by emergency power system or emergency services?

The main intention of emergency power system is to furnish immediate, automatic source of electric power to limited number of selected vital circuits. The emergency power system includes one or more diesel driven emergency generator, which we will learn a bit more on later, emergency switch board and a distributed system. Both emergency generator and emergency switch board are kept above the waterline, to minimize danger from flooding. Emergency services also include the navigation, safety and emergency lights.

All these emergency services should be supplied from the emergency switch board. Emergency switch board has distributed panels for all the emergency services onboard. Emergency switch board as we discussed earlier is always located above the bulkhead deck. This is to ensure that at the time of any emergency such as fire or flooding, the switchboard is not affected and is easily accessible and that any such emergency does not lead to loss of lightening in escape routes and other important navigation control areas.

Thus the main components of an emergency power system are : Emergency generator and emergency lights.

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“Black out” is a condition considered similar to a “dead ship” condition. It is a condition under which the main propulsion plant, boilers and auxiliaries are not in operation and also there is no stored energy available to restore them. This is the time for the emergency generator to take over. The emergency generator has its own prime mover and fuel supply.

As the ship’s emergency generator takes over the battle functions as soon as the main power fails, utmost care should be taken at the time of installation. It’s of extreme importance that load on the generator is at the top of the priority list while considering the factors affecting. This is because when there is a sudden transfer of load from the main generators to the emergency generator there is a high chance of the later getting overloaded. Thus the emergency generators should be of the capacity same as the main generators capacity. To equalize the capacity requirement of the emergency generator to the main generator generally more then one emergency generator should be made available.

These lighting fixtures must provide an uninterrupted source of lighting in the event of power outage. The source of power for these lighting shall consist of accumulator batteries which are continuously charged from the main switch board. All these lights should operate at least for three hours.