HVDC links
Direct-current lines with lower losses over long distances, under the sea and between unsynchronised grids.
Transport · Electricity · No. 51
- Transport
- Form: Electricity
China's Changji to Guquan line sends 12,000 MW of direct current 3,293 km at ±1,100 kV, the highest voltage in service.
Chart: Illustration: HVDC links
Where it comes from
Chart: Map of where it comes from
A converter station turns AC into DC with thyristor or transistor valves. The DC runs on two poles, overhead or in cable, and a second station turns it back into AC.
Three things to know
- Each converter station loses only about 0.7-1% of the power, so DC wins once routes pass about 480 km overhead or 50 km of cable.
- A ship's anchor damaged the EstLink 2 link between Finland and Estonia on 25 December 2024; it returned to the market in June 2025.
- Viking Link between the UK and Denmark was expected to save about 600,000 t of CO2 in its first year.
The journey
- 1 AC gridPower from grids or offshore wind
- 2 RectifierValves convert AC into DC
- 3 DC lineTwo poles, overhead or subsea cable
- 4 InverterSecond station rebuilds AC in step
- 5 Receiving gridExact megawatts delivered where operators choose