Study of power transfer capability of DC systems incorporating AC loads and a parallel AC line

Concepts of maximum power transfer of dc systems and associated ac voltage variations, particularly at inverter stations having low short - circuit ratios, have been extended to include various ac load models and an ac line in parallel with the dc line. The operating capabilities are shown to vary from those predicted from either a Thevenin ac source model or the corresponding short-circuit ratio. The study used an ac/dc load flow program. Keywords - HVDC, short-circuit ratio, power transfer, ac/dc interaction.