Review and development of MMC employed in VSC-HVDC systems

The business case for MMC-HVDC is becoming popular in power transmission systems. Despite their superior potential compared to the AC and LLC-HVDC technologies, MMC-MTDC grid is yet to be efficiently realised in practice. Operation, control and modelling in such VSC-based schemes are arguably the most challenging research and development problems that academia and industry are presently engaged in. This paper endeavours to review the VSC technology on HVDC applications. Simulation cases of two-terminal symmetrical monopole point-to-point MMC-HVDC that later upgraded to three-terminal radial-configured MMC-HVDC are developed on PSCAD/EMTDC to argue the review and to show the flexibility of MMC-HVDC schemes upon severe transient conditions.