Power Transmission By HVDC -Applications and Characteristics

CIM Bulletin, Vol. 71, No. 794, 1978

Lars A. Bergstrom, Manager, HVDC Applications, ASEA Limited, Montreal, Que.

High-voltage direct-current transmission is a relatively new technology. The successful development and operation of AC/DC converters, capable of handling large power blocks, have made HVDC transmission generally accepted by utility engineers and planners around the world. HVDC technology still has significant development potential and, as a result, it is expected that equipment costs will escalate at a substantially slower rate than those of conventional AC equipment. This development will also result in still more compact terminal stations. This paper reviews two modern HVDC installations. In Zaire in Africa, a 1700-km overhead DC line, rated at 500 kv, will supply power to the copper mining district in the Shaba region. Another HVDC link connects Norway and Denmark through a submarine cable rated at 250 kv. This is the longest HVDC cable in the world, 127 km, and the water depth, maximum 530 m, is also much greater than for any previous similar cable. The reasons for selecting HVDC are discussed, and the design and layouts are presented.

Keywords: Equipment, HVDC transmission, Power transmission, Electric power, Skagerrak, Sea cables, Electrodes, Thyristors, Control systems, Filters, Overvoltage, protection, Inga-Shaba.