What is Marine Electricity And How It is Generated?
The ship’s operation is dependent on marine electricity or marine electrical power. Ships without marine electricity would not be capable of running any machinery or performing their core function of sailing from one location to the next.
It is impossible to define Marine Electricity in its entirety. First, we must understand each element separately to fully grasp its meaning.
Marine– The term “marine” is used here to refer to ships, drydocks and other structures that allow cargo to be shipped by sea.
Electricity is a type if energy that results from the existence charged particles (such electrons or protons), either as a statically aggregation or strong as flowing current.
Marine electricity is the electricity produced, supplied, and distributed onboard ships, ports, drydocks, shipyards for running or repairing cargo and passenger vessels.
Marine Electricity Generation
You can generate marine electricity onboard ships using either diesel, shaft, or steam-driven generators.
Marine electricity is used to power inland structures, ports and shipyards.
The generator of the ship has insulated neutral points, which is different from land. It is not connected to or grounded by the ship’s hull. This is to make sure that all machinery is running, even if there’s an earth fault.
International vessels are generally equipped with 3 phase D.C. supplies and a 440v insulated neutral system. Ships like RORO, passenger etc. Large electrical loads require high voltage operating generators. These gensets are available in the range of 3KV – 11KV.
The frequency of power supply can vary depending on where you are located. The 60hz frequency is used on ships. This allows hundreds of motors to run at higher speeds, even though they are smaller.
A transformer is used to reduce the voltage at 440V to 220V or 110V in order for low power signal equipment and lights.
Although all electrical equipment aboard ships is similar to that on land, it has been upgraded to withstand the harsh environment of the sea and moving ship. They can withstand high temperatures, salinity, vibrations, and other hazards.
Parts and components of the Marine Electricity System
Diverse parts of the marine electric system
There are five systems that can be broken down into the electrical onboard ship system:
- Generator system
- Main Switchboard System
- Emergency Switchboard System
- Distribution system
The generator system is composed of an alternator, driver for the alternator, which can either be a diesel-driven engine or a steam-driven one.
Many ships have a shaft generator. This allows the ship’s main engine to rotate the alternator, which generates additional electricity.
These marine generators generate power that is then transported to the Main switchboard via Busbars. The main and emergency switchboards are not equipped with electrical wires for power supply. Bus bars connect all high-voltage and high current systems.
Main Switchboard System
The ship’s main switchboard acts as the distribution hub for the ship’s electrical systems. It receives power from the generator and distributes it to all power consumers spread throughout the ship. It supplies power to all major ships machinery at 440V.
One part of the main switchboard has a 220V supply through a stepdown transformer. It includes bridge equipment, navigation lights, radio communication equipment, etc. The auxiliary switchboard provides power to charge the battery that is used for emergency lighting.
Emergency Switchboard System
If the main generator goes out, an emergency generator must be available to power the switchboard. The emergency generator will automatically start and supply power to the emergency switchboard.
The emergency switchboard is the main point of contact for all emergency equipment. The emergency switchboard can also be divided into two sections, 440V or 220V. This allows for the supply of appropriate machinery and equipment.
The distribution system is located after the switchboard. It consists of the following:
Distribution boxes These boxes contain metal and are used to provide power to specific parts of the ship’s machinery.
Motor starter boxes: Many motors are responsible for operating various mechanical machinery aboard ships. There are many of them. Each motor group is equipped with a starter box that contains their “On and OFF” switch, as well as safety devices. The starter panel contains local gauges for temperature and amperage.
Shore connection boxes: Ships are able to run their machinery using shore power when they are in ports with strict emission controls or dry-docking. A shore panel is located at the accommodation entrance or near the bunker station. It is used to accept shore supply cable.
Lighting distribution panel
The lighting distribution panel provides power for lighting systems, accommodation systems and small heating appliances. It also powers motors with 1/4 HP or less.
Emergency switch-off panel: To protect personnel and ship machinery, there are several Emergency Switch Off Panels that can be used to shut down machinery and equipment in emergency situations.
A distribution system’s main purpose is to provide an alarm and safety solution for any machine or group. Circuit breakers supply power to large auxiliary machines at high voltage. Miniature circuit breakers and supply fuse are used for smaller supplies.
Marine generator working principle
The principle behind the generator is that a magnetic field around the conductor can vary, which causes a current to be induced in it.
Generators are composed of a set of conductors that are wound in coils around an iron core. This is called the stator. This stator is home to the rotating magnet known as the rotor, which creates a magnetic field. The magnetic field creates an induced EMF (or electro-magnetic force) as the mechanical input causes rotor to turn.
Induction in a brushless alternator generates the magnetic field. A rotor winding is energized with DC current through slip rings, brushes and slip rings.
Safety of the marine electricity system
Safety of marine electrical system includes protection of personnel from electric shock and damage to machinery caused by electrical malfunction.
A relay, circuit breaker, or fuse can be used to protect machinery from overcurrent and overheating, depending on its size.
Temperature gauges, RPM motor, direction indicator, amp meter, and others. Different equipment are used to assess the health and performance of electrical machinery.
Books on Marine Electrical System
All maritime professionals need to be familiar with the operation, design and maintenance of marine electrical systems. Maritime professionals often neglect marine electricity during their career. Below is a list of top ebooks about marine electricity written by experts.
Maintenance and troubleshooting marine electrical systems – Volume 1
This ebook, a bestseller in the field of marine electrical, is written exclusively for deck officers, engineers, and other electrical officers. This ebook is essential for everyone.
Marine Control Technology
This ebook, now in its fourth edition, is a comprehensive guide to marine control technology. It also contains information about the most recent developments in the shipping industry.
Marine Electrical Technology
This book is your ultimate source for all things related to marine electric technology. This ebook is essential for all maritime professionals at all levels of the merchant navy.
Testing Electronic Components on Ships and Land
Locating the problem component is an important aspect of diagnosing electrical faults. This will help you determine if it’s faulty. This guide will assist you in understanding how to test electronic components.
Marine High Voltage Technology
This ebook contains all information about marine high voltage equipment and technology, in accordance with STCW 2010 Manila Amendments.
Competency in Marine Electrical Technology
This guide is for applicants and those preparing to apply for competency certificates.
MEO Class IV & ETO
This book contains 3100 questions and answers about marine electrotechnology, electric, electronics, and control engineering.
Applied Marine Control And Automation
This ebook is for those who want to learn more about instrumentation, control engineering, and marine automation.
Explosion Protection Equipment Guide for Mariners
Are you looking to learn how to safely work with hazardous electrical equipment onboard ships of all kinds? This guide is for you.