Three phase harmonic load flow in an unbalanced AC system including HVDC link

Recent technology advances have made HVDC transmission an economically attractive alternative for power transmission over long distances. In unbalanced conditions ,the AC to DC and DC to AC conversion processes in the HVDC transmission ,in addition to characteristic harmonics generate non characteristic harmonics. When calculating non characteristic harmonics generated by HVDC converters, because of unbalance at the AC system ,three phase HVAC/HVDC load flow must be taken in solution. In this paper therefore, equations of three phase HVAC/HVDC load flow is explored. Finally, three phase harmonic load flow was done by three phase frequency scan technique in an unbalanced AC system including HVDC link.