Electric power transmission through interconnectors using high-voltage direct-current (HVDC) involves usually two converter stations and a transmission line. Generally overhead lines are used, but an important class of HVDC projects use submarine power cables. A back-to-back station has no transmission line and joins two separate AC grids at a single point. Historical HVDC systems used the Thury system of motor-generators but these have all been made obsolete by later developments such as mercury-arc valves (now also obsolete), thyristors, and IGBT power transistors.

Legend

Converter technology:

• Thury = Series-connected generators as designed by René Thury

• Merc = Mercury-arc valve rectifier and inverter

• Thyr = Thyristor rectifier and inverter

• IGBT = Insulated gate bipolar transistor

• BIGT = Bi-mode insulated gate transistor

• IEGT = Injection enhanced gate transistor

Line status:

Africa

Australia and Oceania

Asia

Europe

2 As of 9 December 2015, LitPol Link started trial operations. 3 Caithness Moray HVDC serves a number of renewable energy sources in the north of Scotland - see map 4 Contracts due to be placed in 2016. 5 Elia says construction expected to start in late 2017. 6 Date is that quoted to support the Shetland Wind Farm that SSE is a part investor in. 7 Decision on project expected in 2017 following consultation - see SSE PD reference.

North America

South America

Back to back

Maps

Africa

Australia and Oceania

Europe

North America

South America

See also

• Asian Super Grid

• Desertec

• Electrode line

• European super grid

• High-voltage direct current

• List of high voltage underground and submarine cables

• Lyon-Moutiers DC transmission scheme

• Scotland-Norway interconnector

• HVDC converter station

• Super grid

• Submarine power cable

• Transmission tower

• Uno Lamm

• Valve hall

References

Sources