A novel assessment index of LCC-HVDC system impact on short-term voltage stability of the receiving-end AC system

This paper proposes a novel index to quantitatively assess the impact of line commutated converter HVDC (LCC-HVDC) system on short-term voltage stability (STVS) of the receiving-end AC system. The major factor in a LCC-HVDC system to impact STVS is revealed and an analytic method is presented to depict the major factor. On this basis, an assessment index is proposed to quantify the LCC-HVDC system impact on STVS. Compared with short-circuit ratio based indices which only reflect the effects of voltage supporting strength of the receiving-end AC system, the proposed assessment index further takes into account the effects of HVDC system, induction motors, and transmission grid topology. The performance of the proposed assessment index has been validated in a simplified AC/DC system and a real large-scale power system, China Southern Grid.