Ships, over the years, have advanced massively. A modern-day ship is no less than a technological wonder, floating across the oceans throughout the whole wide world, to serve in a multitude of ways. Hence, it should come as no surprise, that in order to operate such heavy and elaborate pieces of tech throughout the ship, we need an active and efficient power generation system on board ships. The following feature is about that exact topic and an effort to make it more absorbable for you.
How is Power Generated?
In a main vessel, usually an A.C. Generator setup is employed in order to cater the Electric needs throughout the ship. A prime mover is used with an alternator to generate A.C. current on the ship.
It is a simple A.C. generator that works on the Principle of Faraday’s law of Electromagnetic induction, which states that Electromotive force is generated when a current carrying circuit is moved in a uniform magnetic field.
An A.C. generator consists of a stator, which is basically an iron core, wound up with copper coils. A rotating magnetic is used as a rotor which rotates within the stator and generates induced EMF which is then transmitted through slip rings and brushes. In this way power generation takes place.
As important it is to efficiently generate electricity on a marine vessel, it is equally important to channel this electricity all across the ship, to power various machinery like Steering, naviga00tion system, communication systems etc. Alternating Current is really easy and convenient to interrupt and control using various power management systems. Stepping-up or down the voltage is also barely an inconvenience while working with A.C. Instruments like Distribution boxes, shore connection boxes, test panels, and motor starter boxes are crucial in order to seamlessly distribute electricity onboard ships. In case of emergency, various circuit breakers and emergency switch-off panels are employed in order to avoid any miss happenings on the ship.
Why is A.C. preferred over D.C.?
Marine Vessels not only require the most efficient power generation, but it is also actively required for the engineers to ensure safety and avoid deadly catastrophe onboard ships. Alternating current is way easier to generate as well as manage and distribute on a vessel.
A.C. is way easier and cheaper to not only generate from alternators, but it is way convenient to convert from one voltage from another by the use of simple and cost-effective transformers, as compared to D.C. which takes a decent effort and cost to transform from one voltage to another.
In case of current leakages, it is way easier to detect an Alternating current leakage in comparison to a Direct Current. Alternating current leakages can be easily detected using a standard GFCI (Ground Fault Circuit Interrupter), whereas in case of D.C., it requires special equipment which are not as cheap and hassle-free compared to a GFCI.
Also, in case of a current overload or short-circuit, A.C. is easier to interrupt using simple devices like MCBs and fuses and hence some serious mishaps can easily be avoided on ships. D.C. on the other hand is notorious to be tough to interrupt, meaning it would again require special and possibly expensive instruments to interrupt and operate on ships, where it is of utmost importance to evade the slightest possibility of a potential fire hazard. Due to the same property of being difficult to interrupt, it is not possible to operate a D.C. with the cost-efficient and space-efficient switchgears as it is the case for A.C.
Therefore, for the plethora of reasons as stated above, it is not favorable to use D.C. onboard ships.
Components of a Power Generation system
So, in order to produce, harness and distribute power throughout the ship, it is obvious that a lot of constituents are going to be involved.
- An A.C. generator is required with a prime mover to produce electricity.
- Main switchboards, which are used to channel this energy to other components of the ship.
- A variety of Circuit breakers and fuses are used throughout the systems to act as a failsafe measure to trip off to avoid breakdown and accidents on the ship.
- The power Distribution system usually operates at around 440V, whereas in some heavy vessels, it can go as high as 6600V. Which is why transformers are also used to step-up or step-down the voltage onboard.
Emergency switchboards also play a crucial role to ensure that the ship can carry on functioning even when the main switchboards are shut down due to some unexpected hazard.
In case of failure of main power supply, or some other accidents leading to the shutting down of the main power supply system, there is a separate Emergency power solution, which either involves batteries or a separate, small-scale power generation system or both in some ships. These batteries and generators are kept away from the main system, preferably located outside the main or auxiliary machinery space. This is done so as to ensure that it is reachable even in case of some unexpected turn of events which might lead to the main machinery space being inaccessible.
It is also to be noted that the emergency power supply should be capable enough to easily deliver the electrical needs of the essential components of the ship, (such as the steering gear system, communication systems, navigation and emergency lights, fire-fighting systems) if not the whole entire vessel until the main power supply is functional again.