High-voltage Direct Current - Advantages of HVDC Over AC Transmission - Cable Systems

Cable Systems

Long undersea / underground high voltage cables have a high electrical capacitance compared with overhead transmission lines, since the live conductors within the cable are surrounded by a relatively thin layer of insulation (the dielectric), and a metal sheath. The geometry is that of a long co-axial capacitor. The total capacitance increases with the length of the cable. This capacitance appears in parallel with the load. Where alternating current is used for cable transmission, additional current must flow in the cable to charge the cable capacitance. This current flow causes energy loss via dissipation of heat in the conductors of the cable. Additional energy losses occur as a result of dielectric loss in the cable insulation.

However, when direct current is used, the cable capacitance is charged only when the cable is first energized or when the voltage is changed; there is no steady-state additional current required. For a long AC undersea cable, the entire current-carrying capacity of the conductor could be used to supply the charging current alone. The cable capacitance issue limits the length and power carrying capacity of AC cables. DC cables have no such limitation, and are essentially bound by only Ohm's Law. Although some DC leakage current continues to flow through the dielectric insulators, this is very small compared to the cable rating and much less than with AC transmission cables.

Read more about this topic:  High-voltage Direct Current, Advantages of HVDC Over AC Transmission

Other articles related to "cable systems, cable":

Gateway UHF Broadcasting - Cable Systems
... Cable Ch ... # Coverage SkyCable 163 (Digital) 5 (Analog) Metro Manila -With several cable TV affiliates nationwide ...
WSFX-TV - History
... Future sister station WECT had a secondary CBS affiliation until cable arrived in the area in the 1970s, while Florence, South Carolina's WBTW covered most of ... the 1970s until WJKA's sign-on, local cable systems piped in either WTVD from Durham, WNCT-TV from Greenville, or WBTW ... matters, Raleigh's WRAL-TV, which had been available on cable in Wilmington for decades, switched to CBS a year after WJKA's sign-on ...
The Adult Channel - History - Spice International
... who hasd secured affiliation agreements for The Adult Channel in over thirty Spanish cable systems ... Benelux countries and in Germany via Deutsche Telekom who had 16 million cable homes user ... In Eastern Europe, securing carriage in cable systems located in Russia, Lithuania, Estonia and Slovenia ...
Tru2way - Deployment
... Plasma televisions using Tru2way in these Comcast cable systems ... In June 2008, six major cable companies had signed a "binding" memorandum of understanding (MOU) to have all of their digital cable systems ready for Tru2way by July 1, 2009 ... However, none of the cable systems that signed the agreement were ready to implement Tru2way ...
List Of United States Stations Available In Canada - Other Stations / Local Coverage - Southern Ontario
... are carried throughout the Greater Toronto Area and Golden Horseshoe on a variety of cable systems ... Call sign Affiliation Available? Notes Rochester, New York WUHF Fox Yes Carried on cable systems in Belleville, Ontario and along the northern shore of Lake Ontario ...

Famous quotes containing the words systems and/or cable:

    What is most original in a man’s nature is often that which is most desperate. Thus new systems are forced on the world by men who simply cannot bear the pain of living with what is. Creators care nothing for their systems except that they be unique. If Hitler had been born in Nazi Germany he wouldn’t have been content to enjoy the atmosphere.
    Leonard Cohen (b. 1934)

    To be where little cable cars climb halfway to the stars.
    Douglass Cross (b. 1920)