Editing HVDC Cross-Channel (section)

== 2,000 MW system (1986) ==
Because the first installation did not meet increasing requirements, it was replaced in 1975–1986 by a new HVDC system with a maximum transmission rating of 2,000{{nbsp}}MW between France and the United Kingdom, for which two new converter stations were built in [[Sellindge]], between [[Ashford, Kent|Ashford]] and [[Folkestone]] in [[Kent]], England and in [[Bonningues-lès-Calais]] (Les Mandarins station), near [[Calais]], France. Unlike most HVDC schemes, where the two converter stations are built by the same manufacturer, the two converter stations of the 2,000{{nbsp}}MW scheme were built by different manufacturers (although both have subsequently become part of the same parent company, [[Alstom]]). The Sellindge converter station was built by [[General Electric Company|GEC]]<ref>Rowe, B.A., Goodrich, F.G., Herbert, I.R., Commissioning the Cross Channel h.v.d.c. link, [[General Electric Company|GEC]] Review, Vol. 3, No. 2, 1987.</ref> and the Les Mandarins converter station was built by CGE Alstom.

This HVDC-link is {{convert|73|km|abbr=in}} long in route, with {{convert|70|km|abbr=in}}  between the two ends.  The undersea section consists of eight {{convert|46|km|abbr=in}} long 270{{nbsp}}kV [[Submarine power cable|submarine cables]], laid between Folkestone (UK) and [[Sangatte]] (France), arranged as two fully independent 1,000{{nbsp}}MW Bipoles, each operated at a DC voltage of ±270{{nbsp}}kV. Cables are laid in pairs in four trenches so that the magnetic fields generated by the two conductors are largely cancelled. The landside parts of the link consist of 8{{nbsp}}cables with lengths of {{convert|18.5|km|abbr=in}} in England, and {{convert|6.35|km|abbr=in}} in France.<ref>Compendium of HVDC schemes, [[International Council on Large Electric Systems|CIGRÉ]] Technical Brochure No. 003, 1987, pp194–199.</ref>

In common with the 1961 scheme, there is no provision to permit neutral current to flow through the sea.  Although each station includes an earth electrode, this is used only to provide a neutral reference, and only one of the two electrodes is connected at a given time so that there can be no current flow between them.

The system was built with solid-state semiconductor [[thyristor valve]]s from the outset. Initially these were air-cooled and used analogue control systems, and in 2011 and 2012 respectively, the thyristor valves of Bipole 1 and Bipole 2 were replaced by modern water-cooled thyristor valves and digital control systems supplied by Alstom.<ref name="areva">{{Cite web |date=2009-12-01 |title=Anglo – French HVDC Link |url=http://www.areva-td.com/solutions/liblocal/docs/Success%20stories/Anglo%20French%20HVDC%20Link%20Cross%20Channel%20Scheme.pdf |url-status=dead |archive-url=https://web.archive.org/web/20140708165537/http://www.areva-td.com/solutions/liblocal/docs/Success%20stories/Anglo%20French%20HVDC%20Link%20Cross%20Channel%20Scheme.pdf |archive-date=July 8, 2014 |access-date=2010-02-28 |publisher=[[Areva]]}}</ref>

This system remains the world's largest-capacity submarine cable HVDC system.<ref>{{Cite web |title=HVDC Submarine Power Cables in the World |url=http://publications.jrc.ec.europa.eu/repository/bitstream/JRC97720/ld-na-27527-en-n.pdf |access-date=6 March 2018 |publisher=Joint Research Centre}}</ref>

In November 2016, during [[Storm Angus]], a ship dragging an anchor cut four of the eight cable components, reducing capacity by 50%.<ref>{{Cite web |date=2 December 2016 |title=How a Loose Anchor Cut Up Britain's Power Link With France |url=https://www.bloomberg.com/news/articles/2016-12-02/how-a-loose-anchor-cut-up-britain-s-power-link-with-france |publisher=[[Bloomberg News]]}}</ref> Repairs were completed by the end of February 2017. The equipment occasionally faults, causing capacity to drop: in a bad year, this might happen several times. To maintain grid frequency and power, the National Grid has a variety of [[Frequency response (electrical grid)|frequency response]] assets, of which [[Battery storage power station|market batteries]] are the first to respond.<ref>{{Cite web |last=Stoker |first=Liam |date=5 June 2019 |title=Batteries act as first responders when UK-France interconnector trips |url=https://www.energy-storage.news/news/batteries-act-as-first-responders-when-uk-france-interconnector-trips |website=Energy Storage News |language=en}}</ref>

In September 2021, a major fire at the Sellindge converter station led to the shutdown of the link.<ref>{{Cite news |date=15 September 2021 |title=National Grid site fire shuts down power cable between France and UK |work=[[BBC News]] |url=https://www.bbc.co.uk/news/uk-england-kent-58570893}}</ref><ref>{{Cite news |last=Ambrose |first=Jillian |date=15 September 2021 |title=Fire shuts one of UK's most important power cables in midst of supply crunch |work=The Guardian |location=London |url=https://www.theguardian.com/business/2021/sep/15/fire-shuts-one-of-uk-most-important-power-cables-in-midst-of-supply-crunch}}</ref> National Grid initially announced that half of the link capacity would be restored within a fortnight, with full capacity being restored in March 2022. The shutdown came at a time of high prices and supply shortage in the UK electricity market, caused by low wind speeds and high prices for natural gas.<ref>{{Cite news |date=16 September 2021 |title=Fire-damaged power link will be out for six months, says National Grid |work=Sky News |url=https://news.sky.com/story/fire-damaged-power-link-will-be-out-for-six-months-says-national-grid-12409414}}</ref><ref>{{Cite web |title=The UK's Energy Price Surge Could be Just Getting Started |url=https://www.poundsterlinglive.com/economics/15947-the-uk-energy-price-surge-could-just-be-getting-started |website=Pound Sterling Live|date=16 September 2021 }}</ref> On 15 October 2021, National Grid announced that half of the link capacity would be restored within the next few days, that 75% capacity would be available between October 2022 and May 2023, and that they hoped to restore full capacity by October 2023.<ref name="guardian-20211015">{{Cite news |last=Ambrose |first=Jillian |date=15 October 2021 |title=Kent's burnt-out electricity cable will take two more years to get back to full service |work=[[The Guardian]] |url=https://www.theguardian.com/business/2021/oct/15/kent-burnt-out-electricity-cable-will-take-two-more-years-to-get-back-to-full-service |access-date=15 October 2021}}</ref>