Electrical installations in the maritime environment

Issue 38 – May 2012

Steam propulsion, which ushered in the era of modern ships, was introduced in the first decade of the nineteenth century. The next major technical milestone – electric power – was initially installed on passenger liners in the early 1880s to provide electric lighting, which was then viewed as providing a significant commercial advantage. As the benefits of electric power became apparent, all ships were soon being designed and equipped with it. Since then, electrical installations have become ever more important in the maritime environment. The International Electrotechnical Commission (IEC) plays a central role in preparing Standards for these.

Harsh environment

Ships and offshore drilling units rely on electrical installations for safe and reliable operation. The installations may be subjected to harsh conditions and environmental or chemical hazards, but should still continue operating. To do so they must meet stringent Standards.

IEC technical committee (TC) 18: Electrical installations of ships and of mobile and fixed offshore units, prepares such Standards for the maritime sector; its subcommittee (SC) 18A deals specifically with Standards for electric cables. An IEC Committee of Action meeting in Bellagio (Italy) in 1927 identified a need for standardisation of electrical installations in ships. This led to a specific advisory committee to work in this domain and this committee then became TC 18.

The provision of electricity is vital to the operation of any vessel and continuity of supply is taken for granted while the crew, sometimes with only the most rudimentary electrical training, must be able to operate a power station with an output of anywhere between a few hundred kilowatts to over 100 MW. At the 1986 meeting of TC 18 in Bergamo, Italy, it was decided to expand the TC's scope to cover electrical installations on board fixed and mobile offshore oil and gas exploration units, as it was felt that the existing Standards for ships were not necessarily appropriate to these environments. In 1988 it was agreed that a separate Standard should be prepared to cover offshore installations.

Leading global adoption

International Maritime Organization (IMO), the United Nations agency with special responsibility for the safety and security of shipping, acknowledging the IEC's expertise, established a formal relationship with TC 18 to collaborate in the field of electrical systems on ships and offshore units.

A central part of IMO activity is to adapt the Safety of Life at Sea Convention (SOLAS) to changes in technology and safety requirements as they occur. This convention applies to all commercial international seagoing ships of 500 gross tonnes and above. Rather than opting to develop their own standards, most of the industry's bureaus or registers of shipping, such as the American Bureau of Shipping, Bureau Veritas, Det Norske Veritas, Lloyd's Register, the Korean Register of Shipping, and the Russian Maritime Register of Shipping, to name just a few, rely on IEC Standards as their preferred choice.

IEC 60092, the series of Standards for Electrical installations in ships, the first edition of which was published in 1957, is referenced in the SOLAS Convention. Thus all the Standards in the series are used extensively at a global level. Both the Standards for ships and those for mobile and fixed offshore installations are implemented worldwide by naval architects, marine engineering design and consulting companies, and all industries involved in the shipbuilding and related sectors.

These Standards are used to support regulations and as the basis for contracts, and often replace the statutory authority documents.

Coping with increased power and computing

As the electrical power requirements of modern ships continue to increase, there is a tendency to introduce higher operating voltages for power consumers, propulsion, and machinery auxiliaries.

Currently the most important technical developments in the shipbuilding and offshore industry relate to the increasing use of computer hardware and software control and monitoring systems for machinery and the introduction of additional and more sophisticated passenger/crew safety systems. The latter include addressable fire alarm and low level lighting systems, and passenger and crew address systems.

Problems are already being seen with the increased complexity of systems on board vessels, which has outstripped the ability of shipbuilders and operators to understand and deal with the systems installed.

Fire

Fire has always been a major threat to mariners: they have nowhere to escape to and no external aid is available. Today there is a growing understanding not only of the dangers of fire but also of the consequences of the spread of fire and of the risks associated with smoke. Special attention is paid to characteristics such as flame retardancy, fire resistance, smoke emission, toxicity, corrosivity, and halogen-free materials for both electrical equipment and cables.

Bigger, faster ships on the horizon

The current types of ship will continue to exist but will do so in parallel with new, larger, and more efficient container and passenger ships. High-speed vessels of a variety of types and sizes will also be introduced, accompanied by requirements to reduce the weight of all installed machinery and systems, including electrical installations.

Energy efficiency aimed at reducing greenhouse gas emissions from ships is under discussion within IMO. This may lead to more efficient power generation and distribution system and TC 18 is closely monitoring developments there.

Ship to shore connections cutting pollution in ports

To cut heavy fuel consumption and reduce greenhouse gases, such as CO2 and NOx (nitrogen oxide), and noise from ships while in port, today there is a tendency to provide electrical power from shore to ships while in port. In 2009, TC 18 issued a PAS (publicly available specification), IEC 60092-510, Electrical installations in ships – Part 510: Special features – High-voltage shore connection systems, giving requirements for such shore connections.

This Standard has now been further developed in cooperation with the International Organization for Standardization (ISO) and the Institute of Electrical and Electronics Engineers (IEEE) into an international Standard, IEC/ISO/IEEE 80005-1, Utility connections in port – Part 1: High Voltage Shore Connection (HVSC) Systems – General requirements. Publication of this Standard is expected in the second quarter of 2012.

There has also been collaboration with IEC SC 23H: Industrial plugs and socket-outlets, which has prepared Standards for plugs, socket-outlets, and ship couplers for HVSC systems.

More environmental issues

Environmental issues are becoming more important with the rise in public and political concern over pollution and global warming. This is impacting national and international legislation and the Standards developed to support these.

TC 18 is aware that laws in different countries focus on the restrictions on the usage of hazardous materials, substances, and processes. The committee is conscious of the need to protect the environment and strives to ensure that the materials employed in the installations are environmentally friendly and cause the minimum of pollution possible.

Electrical propulsion

The shipping industry is also experiencing a shift towards electric and hybrid propulsion systems. This started in the cruise ship industry and is due primarily to the development of power electronics.

Hybrid solutions use a combination of diesel engines or gas turbines, generators, batteries, and motors to drive the propulsion system; they will require improved and modified Standards. A move to variable speed auxiliary drives is also being seen for the same reasons. The Standard for electrical propulsion is being updated and a revised Standard is expected in 2013.

Mobile and fixed offshore installations

The first Standard in the IEC 61892 series for offshore installations was issued in 1997. The series consists of seven publications covering general requirements, system design, equipment, choice and installation of cables, mobile offshore units, installation requirements, and hazardous areas. It was completed in 2007.

The offshore series is a referenced document in the IMO Code for the construction and equipment of mobile offshore drilling units (MODU) Code. The Standards are referenced by three national regulatory bodies but are widely used by oil companies and major drilling contractors.

Multilateral cooperation

Even if the electrical system is an important part of a ship or an offshore unit, it is only one of a number of systems required for full functionality of the ship or offshore unit. This means that collaboration with other standardisation bodies such as ISO or IEEE is necessary in addition to close cooperation with IMO.

Given the extent of its scope and the expansion and fast-changing pace of the shipping and offshore sectors, TC 18 has a busy schedule ahead, updating a number of international Standards and preparing new ones.

Related Touchstone article

Summarised from IEC's 'e-tech', April 2012.

Published in energy.