A Commentary on Voltage Stability of Multi-Infeed AC/DC System with VSC-HDVC

Multi-Infeed Direct Current (MIDC) system has become a development trend of the power grid. The complexity interactions between AC/DC system, and among DC subsystems have brought new challenges to voltage stability of the system. Aim at the stability problem of MIDC systems, voltage source converter based HVDC (VSC-HVDC) is applied to MIDC systems for improving the voltage characteristic of common AC bus in MIDC systems. For its flexible control performance and reactive power double-flow, VSC-HVDC system provides favorable conditions to improve the voltage stability of multi-infeed AC/DC power. Based on the strongly nonlinear and coupled characteristics of MIDC systems, this paper gives a commentary on voltage stability of multi-infeed AC/DC power system with VSC-HDVC. Finally, the problems to be solved in the research on voltage stability of multi-infeed AC/DC power transmission system and the future research direction in this field are also discussed. It should be the subjects investigated in future to apply the VSC-HVDC to MIDC systems for improving the voltage stability of MIDC AC/DC systems.