A high-voltage, direct current (HVDC) Electric power transmission system uses direct current for the bulk transmission of electrical power, in contrast with the more common alternating current (AC) systems. For long-distance distribution, HVDC systems are less expensive and suffer lower electrical losses. For shorter distances, the higher cost of DC conversion equipment compared to an AC system may be warranted where other benefits of direct current links are useful.
The modern form of HVDC transmission uses technology developed extensively in the 1930s in Sweden at ASEA. Early commercial installations included one in the Soviet Union in 1951 between Moscow and Kashira, and a 10-20 MW system in Gotland, Sweden in 1954. The longest HVDC link in the world is currently the Inga-Shaba 600 MW link connecting the Inga Dam to the Shaba copper mine, in the Democratic Republic of Congo.
- ↑ Wikipedia: http://en.wikipedia.org/wiki/High-voltage direct currentfckLR