Comparison with AC Advantages A long-distance, point-to-point HVDC transmission scheme generally has lower overall investment cost and lower losses than an equivalent AC transmission scheme. Although HVDC conversion equipment at the terminal stations is costly, the total DC transmission-line costs over long distances are lower than for an AC line of the same distance. HVDC requires less conductor per unit distance than an AC line, as there is no need to support three phases and there is no skin effect. AC systems use a higher peak voltage for the same power, increasing insulator costs.
comparison with ac advantages a long-distance point-to-point hvdc transmission scheme generally has lower overall investment cost and lower losses than an equivalent ac transmission scheme although hvdc conversion equipment at the terminal stations is costly the total dc transmission-line costs over long distances are lower than for an ac line of the same distance hvdc requires less conductor per unit distance than an ac line as there is no need to support three phases and there is no skin effect ac systems use a higher peak voltage for the same power increasing insulator costs