HVDC Cross-Channel

The HVDC Cross Channel is the high voltage direct current connection that operates under the English Channel between the European and British electricity grids.

The first connection of this kind went into service in 1961 between static inverter plants at Lydd in England and Echinghen, near Boulogne-sur-Mer, in France. This scheme was equipped with mercury vapour rectifiers. 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 and was operated symmetrically at a voltage of 100 kV and a maximum current of 800 amperes. The maximum transmission power of this facility was therefore 160 megawatts.

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 2000 megawatts between France and Great Britain, for which two new static inverter plants were built in Sellindge (UK) and in Bonningues-lès-Calais (Les Mandarins station), near Calais, (France). This new HVDC-link is 73 km long in route, with 70 km between the two ends. The undersea section consists of eight 46 km long 270 kV submarine cables, laid between Folkestone (UK) and Sangatte (France), arranged as two independent bipoles. The landside parts of the link consist of 8 cables with lengths of 18.5 km in England, and 6.35 km in France.

As of 2005 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 Europe for clean electricity, and increasing electricity demand within France. [http://web.archive.org/web/20061209070803/http://www.dti.gov.uk/files/file11257.pdf?page=63]

External links

* [http://www.nationalgrid.com/uk/Interconnectors/France/ Interconnectors - France] , National Grid plc