Research on Supporting Characteristics of VSC HVDC for Multiple Feed-in System

Although with large capacity of hydro power, Central China Power Grid is considered as an important load center in China. And with the increasing electricity consumption, it has been developed to a multiple LCC HVDC (line-commutated converter HVDC) feed-in architecture and its transient characteristics have profoundly changed. In this scenario, a reasonable partition with VSC HVDC (voltage-sourced converter HVDC) link has been a possible choice. Evaluation of DC access capability and the strength of the interregional connection with VSC HVDC connection becomes an urgent issue. This paper investigates the indexes for evaluating the strength of multi-feeder systems, the calculation of short-circuit ratio based on operating impedance, and further discusses the transient support schemes with VSC HVDC partition.