A Novel Operation Boundary Searching Approach for MMC-HVDC System

A novel operation boundary searching approach for modular multilevel converter high-voltage direction current (MMC-HVDC) system is proposed in this paper. Firstly, the mathematical model of MMC-HVDC system is illustrated from the inverter side. Secondly, the operation boundary searching problem is transformed into determining the maximum and minimum reactive power output of MMC-HVDC system under a providing active power transmitted circumstance. Thirdly, the effectiveness of proposed searching approach is verified by the case study of Xiamen-Jinmen power system inter-connection project. It is illustrated that the proposed searching approach is able to provide accurate operation region as the traversal method. Meanwhile, the computation expanse is saved since only the maximum and minimum reactive power is optimized for the same active power, rather than all the possible reactive power transmission condition.