The HVDC Cross-Channel is the high voltage direct current (HVDC)

High-voltage direct current

A high-voltage, direct current electric power transmission system uses direct current for the bulk transmission of electrical power, in contrast with the more common alternating current systems. For long-distance transmission, HVDC systems may be less expensive and suffer lower electrical losses...

 connection that operates under the English Channel

English Channel

The English Channel , often referred to simply as the Channel, is an arm of the Atlantic Ocean that separates southern England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest to in the Strait of Dover...

 between the continental European and British electricity grids.

1961 cable

The first HVDC Cross-Channel went into service in 1961 between static inverter plant

Static inverter plant

A static inverter station, also known as an HVDC Converter Station, is the terminal equipment for a high-voltage direct-current transmission line, in which direct current is converted to three-phase alternating current, and, usually, the reverse...

s at Lydd

Lydd

Lydd is a town in Kent, England, lying on the Romney Marsh. It is one of the larger towns on the Marsh, and the most southerly town in Kent. Actually located on Denge Marsh, Lydd was one of the first sandy islands to form as the bay evolved into what is now called the Romney Marsh...

 in England and Echinghen

Echinghen

Echinghen is a commune in the Pas-de-Calais department in the Nord-Pas-de-Calais region of France.-Geography:A farming village, some southeast of Boulogne, at the junction of the D127 and the D127e4 roads.-Population:-References:* -External links:...

, near Boulogne-sur-Mer

Boulogne-sur-Mer

-Road:* Metropolitan bus services are operated by the TCRB* Coach services to Calais and Dunkerque* A16 motorway-Rail:* The main railway station is Gare de Boulogne-Ville and located in the south of the city....

, in France. This scheme was equipped with mercury vapour rectifiers

Mercury arc valve

A mercury-arc valve is a type of electrical rectifier used for converting high-voltage or high-current alternating current into direct current . Rectifiers of this type were used to provide power for industrial motors, electric railways, streetcars, and electric locomotives, as well as for...

. In order to keep the disturbances of the magnetic compasses of passing ships as small as possible, a bipolar cable was used. The cable had a length of 64 kilometres (39.8 mi) and was operated symmetrically at a voltage of 100 kV and a maximum current of 800 amperes. The maximum transmission power of this cable was 160 megawatts (MW). The cable was built by ABB Group.

1986 cable

Because the first installation did not meet increasing requirements, it was replaced in 1985–1986 by a new HVDC line with a maximum transmission rate of 2,000 MW between France and Great Britain, for which two new static inverter plant

Static inverter plant

A static inverter station, also known as an HVDC Converter Station, is the terminal equipment for a high-voltage direct-current transmission line, in which direct current is converted to three-phase alternating current, and, usually, the reverse...

s were built in Sellindge

Sellindge

Sellindge is a civil parish and village on the A20 road between Ashford and Folkestone in Kent, South East England. Sellindge is part of North Downs West Ward of Shepway District Council but part of the Elham ward of Kent County Council....

 (UK) and in Bonningues-lès-Calais

Bonningues-lès-Calais

Bonningues-lès-Calais is a commune in the Pas-de-Calais department in the Nord-Pas-de-Calais region of France.-Geography:A farming village located 5 miles southwest of Calais, on the D243 road near to junction 39 of the A16 autoroute....

 (Les Mandarins station), near Calais

Calais

Calais is a town in Northern France in the department of Pas-de-Calais, of which it is a sub-prefecture. Although Calais is by far the largest city in Pas-de-Calais, the department's capital is its third-largest city of Arras....

, (France). The cable and substations were built by Areva

Areva

AREVA is a French public multinational industrial conglomerate headquartered in the Tour Areva in Courbevoie, Paris. AREVA is mainly known for nuclear power; it also has interests in other energy projects. It was created on 3 September 2001, by the merger of Framatome , Cogema and...

. This HVDC-link is 73 kilometres (45.4 mi) long in route, with 70 kilometres (43.5 mi) between the two ends. The undersea section consists of eight 46 kilometres (28.6 mi) long 270 kV submarine cable

Submarine power cable

Submarine power cables are major transmission cables for carrying electric power below the surface of the water. These are called "submarine" because they usually carry electric power beneath salt water but it is also possible to use submarine power cables beneath fresh water...

s, laid between Folkestone

Folkestone

Folkestone is the principal town in the Shepway District of Kent, England. Its original site was in a valley in the sea cliffs and it developed through fishing and its closeness to the Continent as a landing place and trading port. The coming of the railways, the building of a ferry port, and its...

 (UK) and Sangatte

Sangatte

Sangatte is a commune in the Pas-de-Calais department on the northern coast of France on the English Channel.Like many place names in French Flanders, the name is of Flemish origin and means "gap in the sand".-Engineering:...

 (France), arranged as two independent bipoles. The landside parts of the link consist of 8 cables with lengths of 18.5 kilometres (11.5 mi) in England, and 6.35 kilometres (3.9 mi) in France.

Significance

imports of electricity from France have historically accounted for about 5% of electricity available in the UK. Imports through the interconnector have generally been around the highest possible level, given the capacity of the link. In 2006, 97.5% of the energy transfers have been made from France to UK, supplying the equivalent of 3 million English homes. The link availability is around 98%, which is among the best rates in the world. The continued size and duration of this flow is open to some doubt, given the growth in demand in continental Europe for clean electricity, and increasing electricity demand within France.

Sites

! Site >

Coordinates
Echingen Static Inverter Plant (out of service)	50°41′48"N 1°38′21"E
Lydd Static Inverter Plant (out of service)	50°54′54"N 0°56′50"E
Les Mandarins Static Inverter Plant	50°54′11"N 1°47′5"E
Sellindge Sellindge Sellindge is a civil parish and village on the A20 road between Ashford and Folkestone in Kent, South East England. Sellindge is part of North Downs West Ward of Shepway District Council but part of the Elham ward of Kent County Council....  Static Inverter Plant	51°6′21"N 0°58′32"E

External links

• Interconnectors - France, National Grid plc
  National Grid plc
  National Grid plc is a multinational electricity and gas utility company headquartered in London, United Kingdom. Its principal activities are in the United Kingdom and northeastern United States and it is one of the largest investor-owned energy companies in the world.National Grid is listed on...
  
  
• Timesonline Story
• http://web.archive.org/web/20051115122606/www.transmission.bpa.gov/cigresc14/Compendium/CROSS2.htm
• http://web.archive.org/web/20051115122606/www.transmission.bpa.gov/cigresc14/Compendium/Cross2%20Pictures.pdf