Modeling of ±800kV Multi-terminal LCC-MMC HVDC Controller

Combining the advantages of line commutation converter and flexible direct current transmission based on modular multilevel converter, LCC is adopted as power convergence converter station for high voltage and large capacity at sending end, LCC converter station is used in heavy load concentrated area at receiving end to provide AC power, and MMC converter station with multiple terminals is used for other areas with relatively light load to distribute electric energy flexibly. In this paper, a coordination control strategy for multi-terminal LCC-MMC system is proposed based on the ±800kV Baihetan hydropower DC transmission project with the above topology. A unipolar model of Baihetan DC project is built on PSCAD. The hybrid system can run smoothly and steadily when transmitting power. The validity of the control strategy proposed in this paper is verified.