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, and the first HVDC link to be embedded within an AC system, rather than interconnecting two asynchronous systems.
[2] 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 converter 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.
However the capacitor banks located at Kingsorth were used for voltage control on the network.