Submarine communications cable

A submarine cable ( sometimes called underwater cable) is a misplaced in a water body cable for communication or for the transmission of electrical energy. Submarine cables for power transmission can not be operated with standard three-phase AC power from about 70 km in length, then the more complex high-voltage direct current (HVDC ) must be used. Postponed they are usually prepared by special vessels, so-called cable-laying.

Submarine cables must be built extremely sturdy due to the technically demanding maintenance. Monopolar submarine cables for high-voltage direct -current transmission must be marked on nautical charts as they can interfere significantly with their magnetic compass systems of ships.

• 4.1 Communication Cables
• 4.2 Three-phase cable
• 4.3 DC cable

Telecommunications cable in the deep sea

Submarine cable provides data communication over long distances. Submarine cable can carry vast amounts of data, more than even large communication satellites. Another advantage over satellite links is the significantly lower running time of the signals. They share one major drawback, however, with satellites: submarine cable as well as satellite can be modified only with great effort, maintained, extended, or a way to edit afterwards on otherwise.

Especially due to the high data volume submarine cable used particularly frequently in the Atlantic between North America and Europe. There are only a few countries that still have no access to a high-performance communications cable.

At the beginning of analog electrical signals were still transmitted. By now lying on the seabed strands of fiber optic cables. A fiber optic cable contains multiple pairs of fibers, which laid in the North Atlantic TAT -14, for example, four. About one fiber pair can flow at one time by the so-called "multiplexing" many data streams. Latest fiber pairs may well transmit a terabit of data per second. The fiber optic cables are in a copper tube, which is filled with water-repellent composite material. To this copper tube is still a tube of aluminum to protect against salt water, followed by steel cables and, depending on the strength of protection, several layers of plastic. The copper tube serves as an electrical conductor to provide the required at intervals ( in modern cables 50-80 km ) into the cable spliced ​​optical amplifier with current. As a return conductor of the sea water used. The operating voltage reaches the order of 10 kV. Before the coasts because of the rising seabed and the associated risk of damage from ship anchors or fishing trawler stronger armored cable used. However, these measures do not always help. On 28 February 2012 Waiting on a berth in the port of Mombasa ship severed an undersea cable with its anchor and laid a substantial part of Internet connectivity in East Africa lame.

Laying of submarine cables

In shallow water, the lines using a special vehicle, called a sea plow, buried in the seabed. Water is sprayed from the water tank to the sea plow under high pressure of 1,600 bar in the sand, so that quicksand is created and the cable can sink In sandy soil. The sand solidifies again and then covered the cable. At the beach the cable is routed into a shaft and guided to the landing site. The installation work can be carried out only at low tide.

History

Telegraph cable

1811 already sent the German Samuel Thomas Soemmering electrical signals through an insulated rubber wire, which had been transferred by the Isar near Munich.

However, these early attempts diseased especially at suitable insulation. So the idea of ​​laying of submarine cables have been tried several methods since the invention of the electric telegraph. But it was the invention of the gutta-percha - Press in 1847 by Werner Siemens made ​​it possible for underwater installation well-insulated cable.

On 28 August 1850, laid between Dover and Cap Gris -Nez, near Calais, the first submarine cable, which was, however, interrupted the next day after the transmission of a first telegram from a fishing boat with his nets. A year later an armored submarine cable between Britain and France was laid. This proven and solved the installation of additional submarine cable from - not always with a long shelf life.

Experiments, such as laying a cable in the Mediterranean Sea between Algeria and Sardinia, but initially failed due to poor equipment. For example, lacked a suitable cable brake, with which one could control the unwinding of the cable from the cable drum even at great water depths. Such was available only with Werner Siemens ' dynamometer.

Since that time still took the sending of a message from America to the UK for over a week, Cyrus W. Field had the idea to lay a cable on the seabed of the Atlantic.

In 1856, which was "Atlantic Telegraph Co. " was founded in order to raise the necessary funds through the sale of shares. Should be laid over a 4500 km long cable from Ireland to Newfoundland. The vessels used, Agamemnon and Niagara, began on August 3, 1857 at Ireland, had after several unrecoverable cable losses and fractures give up but after some time after the final loss of the cable.

After exercises in the Bay of Biscay in spring 1858 and another hapless attempt in June 1858, the company succeeded in the third, started on July 17 start after some troubles eventually and on August 5, the connection was made ​​. On 16 August this first submarine cable between Ireland and Newfoundland West with the exchange of congratulatory telegrams between Queen Victoria and the U.S. President James Buchanan was put into operation. However, the initial attraction developed into a large bust, because the transmission of the message of greeting the Queen to the American president took 16 hours, although they comprised only 103 words. In September 1858, the cable failed; probably the gutta-percha casing had been damaged during installation, so the cable was no longer adequately protected against corrosion by sea water. The problem was that at that time was the topography and seabed hardly known.

1864 5100 km submarine cable has been prepared with improved protective coating and the " Great Eastern " procured as lay vessel, at that time the largest line of steamers in the world. On 31 July 1865, the cable ripped during installation. Only in 1866 could be installed on the second attempt the first cable, the long-term ensured the telegraph line between America and Europe.

A few years later succeeded mainly the British, to achieve both the United States by means of submarine cables as well as on Freetown in Sierra Leone, the African continent. Another submarine ran over Freetown to Cape Town.

Egypt became an important relay station for the submarine cable telegraphy. In 1868, a submarine cable from the island of Malta was moved to Alexandria in Egypt. This section joined after 1870 indirectly London with Bombay.

The high resistance of this long cable weakened the signal much the incoming signal must therefore be evaluated by means of mirror galvanometer. Applications other than telegraphy were not feasible.

Telephone cable

From 1950, submarine cables were possible with spliced ​​amplifiers for transmission of telephone signals. The amplifiers were supplied via the inner conductor of the cable with high voltage return wire was the sea. In 1956, the first transatlantic telephone cable was laid.

Fiber optic cable

In the early 1980s the optical communication was so far advanced that the British Post Office in 1980 tentatively moved first Glasfaserseekabel in the Scottish Loch Fyne. 1984, the first fiber optic link from the island to the Isle of Wight was commissioned in 1986 by the English Channel. In 1988, with TAT- 8, the first transatlantic fiber-optic cable in operation. Until the mid- 1990s, the copper cables were also because of the capacity additions required by the development of the Internet, practically completely.

Selected submarine cable

Communication Cables

• ALBA -1 (Cuba ↔ Venezuela)
• Apollo ( Europe ↔ North America )
• Cantat ( Canada ↔ Scotland)
• COMPAC ( Canada ↔ ↔ Hawaii New Zealand - Australia)
• EASSy ( East Africa ↔ Asia, Europe), since 30 July, 2010 Operating
• HW ( California ↔ Hawaii)
• ICECAN ( Iceland ↔ ↔ Greenland Canada )
• SAFEC (Taiwan ↔ Japan)
• SAT-3/WASC/SAFE (South Africa, Namibia, Angola, Democratic Republic of the Congo, Republic of Congo, Cameroon, Nigeria, Togo, Ghana, Ivory Coast, Cape Verde, the Canary Islands ↔ Portugal) completed since 1999 and 2000 respectively
• SCOTICE (Scotland ↔ Iceland )
• SEA-ME -WE ( South East Asia Middle East ↔ ↔ Western Europe)
• TAT ( UK ↔ North America )
• T.P.C. (Hawaii ↔ Japan)
• Trans-Pacific Express (TPE ) (USA ↔ China)
• Ready Unity ( America ↔ Asia), since April 1, 2010
• WACS ( West Africa South Africa ↔ ↔ ↔ Portugal London), probably from the second quarter of 2012

Three-phase cable

• Submarine cables Sweden Bornholm (60 kV)
• Spain - Morocco undersea cables (380 kV)
• Oresund cable (380 kV)
• Submarine cables through the Strait of Messina (380 kV), as a replacement for an overhead line crossing
• Submarine cables Isle of Man - England, with a length of 105 km, the longest -powered three-phase AC submarine cables worldwide
• Submarine St. Peter Ording - Helgoland " Helgoland cable " (30 kV)

DC power cable

See high voltage direct current transmission

• HVDC Gotland
• HVDC Cross - Channel ( submarine England - France)
• HVDC Inter- Iceland ( line connection between the two islands of New Zealand )
• Kontiskan ( submarine cable between Sweden and Denmark)
• SACOI ( submarine cable between Italy, Corsica and Sardinia )
• HVDC Vancouver - Iceland ( submarine cable link between the Canadian mainland and Vancouver Iceland )
• HVDC Hokkaido Honshu ( submarine cable link between the Japanese islands of Hokkaido and Honshu )
• HVDC Cross - Skagerrak ( submarine cable link between Norway and Denmark)
• Kontek ( submarine cable link between Germany and Denmark)
• Baltic Cable ( submarine cable link between Germany and Sweden)
• SwePol ( submarine cable between Sweden and Poland)
• HVDC Italy- Greece ( submarine cable between Italy and Greece)
• HVDC Leyte - Luzon ( submarine cable link between the islands of Leyte and Luzon in the Philippines )
• Kii Channel HVDC ( submarine cable by the Kii Channel )
• HVDC Moyle ( submarine cable between Scotland and Northern Ireland)
• Bass Strait ( submarine cable between Australia and Tasmania )
• NorNed ( submarine cable between Norway and the Netherlands )
• BritNed ( submarine cable link between the UK and the Netherlands )

Submarine cables in the literature

• Under the heading " The first word of the ocean ", Stefan Zweig describes the laying of the first transatlantic cable as a great moment of humanity ( Stefan Zweig: Great moments of humanity Fischer, Frankfurt aM 2002 - Jubiläumsausg. . )
• Noise is a novel by John Griesemer, who has the first installation of a submarine cable between Europe and America in the 19th century on the subject (ISBN 3-596-51000-7 ).
• John Steele Gordon: A Thread Across the Ocean: The Heroic Story of the Transatlantic Cable. Publisher: Harper Perennial ( July 1, 2003) ISBN 978-0-0605-2446-3
• William Thompson: The Cable: The Wire That Changed the World. Publisher: Tempus ( May 28, 2007) ISBN 978-0-7524-3903-7
• Chester G. Hearn: Circuits in the Sea. The Men, the Ships, and the Atlantic Cable. Publisher: Praeger ( August 30, 2004 ) ISBN 978-0-2759-8231-7 (English)