Research on control and protection system for Shanghai Nanhui MMC VSC-HVDC demonstration project

The modular multilevel converter (MMC) is a newly introduced switch-mode converter topology with the potential for high-voltage direct current (HVDC) transmission applications. This paper mainly focuses on the hierarchical structure, functional components and hardware configuration of the control and the protection (C&P) system for MMC VSC-HVDC. The overall structure of (C&P) system based on design and realization of system controller(SC), valve base controller (VBC) and sub-module controller (SMC) are proposed. The experimental results are introduced with the dynamic imitation system and Shanghai Nanhui VSC-HVDC demonstration project, which validates the good performance of proposed C&P system both at steady and transient conditions so as to suitable application in practical VSCHVDC project.