HVDC Kingsnorth
Encyclopedia
HVDC Kingsnorth was a high-voltage direct-current
(HVDC) transmission system at Kingsnorth
in Kent
. It was at one time the only application of the technology of high voltage direct current transmission for the supply of transformer stations in a city.
It was designed in the first half of the 1970s and went into service in 1975. It ran from Kingsnorth power station
as a 59 kilometers long bipolar (3-wire) underground cable. The positive pole operating at a voltage of +266 kV terminated at the static inverter station
in Beddington
near Croydon
. The negative pole continued to run a further 26 kilometers at -266 kV line to a similar station at Willesden
in North London.
There was also the possibility, if the static inverter station in Kingsnorth was out of service, to run the system as monopolar HVDC between the Beddington and Willesden stations. The HVDC Kingsnorth was the last HVDC equipped with mercury vapour rectifiers, whereby each static inverter for 266kV consisted of two six-pulse valve bridges for 132kV switched in series, which were each fed via a star-star and a star-delta switched transformer.
All later-built HVDC systems used thyristor
valves. The HVDC Kingsnorth could transfer a maximum power of 640 megawatts (320 megawatts per pole).
The system described was shut down according http://www.ece.uidaho.edu/hvdcfacts/Projects/HVDCProjectsListingMay2008-existing.pdf in 1987 following system reinforcement on the network it was embedded in. However the capacitor banks located at Kingsorth were used for voltage control on the network. These were later removed from the system completely in the mid 1980s? (1990s?) as they contained PCB
.
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Coordinates
Kingsnorth Static Inverter Plant ( out of service)
51°25′11"N 0°35′46"E
London-Beddington Static Inverter Plant ( out of service)
51°22′23"N 0°7′38"W
London-Willesden Static Inverter Plant ( out of service)
51°32′41"N 0°15′29"W
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...
(HVDC) transmission system at Kingsnorth
Kingsnorth (Medway)
Kingsnorth is a place in Kent, England, on the south side of the Hoo Peninsula. It is distinct from the village of Kingsnorth, also in Kent, near Ashford. The nearest village is Hoo St Werburgh and the nearest town Rochester, Kent....
in Kent
Kent
Kent is a county in southeast England, and is one of the home counties. It borders East Sussex, Surrey and Greater London and has a defined boundary with Essex in the middle of the Thames Estuary. The ceremonial county boundaries of Kent include the shire county of Kent and the unitary borough of...
. It was at one time the only application of the technology of high voltage direct current transmission for the supply of transformer stations in a city.
It was designed in the first half of the 1970s and went into service in 1975. It ran from Kingsnorth power station
Kingsnorth power station
Kingsnorth is a dual-fired coal and oil power station on the Hoo Peninsula at Medway in Kent, South East England. The four-unit station is owned and operated by energy firm E.ON UK, and has a generating capacity of 1,940 megawatts. It is capable of operating on either coal or oil though in practice...
as a 59 kilometers long bipolar (3-wire) underground cable. The positive pole operating at a voltage of +266 kV terminated at the static inverter station
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...
in Beddington
Beddington
Beddington is a settlement between the London Boroughs of Sutton and Croydon. The BedZED low energy housing scheme is located here. In Beddington was a static inverter plant of HVDC Kingsnorth....
near Croydon
Croydon
Croydon is a town in South London, England, located within the London Borough of Croydon to which it gives its name. It is situated south of Charing Cross...
. The negative pole continued to run a further 26 kilometers at -266 kV line to a similar station at Willesden
Willesden
Willesden is an area in North West London which forms part of the London Borough of Brent. It is situated 5 miles north west of Charing Cross...
in North London.
There was also the possibility, if the static inverter station in Kingsnorth was out of service, to run the system as monopolar HVDC between the Beddington and Willesden stations. The HVDC Kingsnorth was the last HVDC equipped with mercury vapour rectifiers, whereby each static inverter for 266kV consisted of two six-pulse valve bridges for 132kV switched in series, which were each fed via a star-star and a star-delta switched transformer.
All later-built HVDC systems used thyristor
Thyristor
A thyristor is a solid-state semiconductor device with four layers of alternating N and P-type material. They act as bistable switches, conducting when their gate receives a current trigger, and continue to conduct while they are forward biased .Some sources define silicon controlled rectifiers and...
valves. The HVDC Kingsnorth could transfer a maximum power of 640 megawatts (320 megawatts per pole).
The system described was shut down according http://www.ece.uidaho.edu/hvdcfacts/Projects/HVDCProjectsListingMay2008-existing.pdf in 1987 following system reinforcement on the network it was embedded in. However the capacitor banks located at Kingsorth were used for voltage control on the network. These were later removed from the system completely in the mid 1980s? (1990s?) as they contained PCB
Polychlorinated biphenyl
Polychlorinated biphenyls are a class of organic compounds with 2 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings. The chemical formula for PCBs is C12H10-xClx...
.