The advantages of a Direct Current (DC) link over an Alternating Current (AC) link are:

High voltage direct current (HVDC) technology is superior to the more common AC technology for transmission of bulk power over long distances or when transmitting between non-synchronous AC systems. HVDC advantages include:

• Lower electrical losses
• Lower T-line costs (partially offset by converter costs)
• Reduced environmental impact from more compact rights-of-way
• No AC EMF issues
• Direct power delivery and absence of loop flow

Economic Considerations

High Voltage Direct Current (HVDC) is economically superior to other applications when power flows exceed 1,000 MW and distances reach 500 miles or more.

Environmental Issues

An HVDC transmission system provides environmental benefits over conventional AC technology. The land coverage and the associated right-of-way are less for a DC transmission line. DC transmission lines require two conductors versus three AC lines. This reduces the visual impact and allows greater power to flow over the same right-of-way, thus maximizing resources. In addition, the Electromagnetic Force (EMF) effects associated with HVAC transmission lines are not present in the HVDC lines.