Start Control for the MMC-HVDC

2019 4th Asia Conference on Power and Electrical Engineering

能源学;电工学

Zhang, Xiaoliang^1 ; Ning, Lianhui^1 ; Yin, Yanjiao^1 ; Zhao, Boyang^1 ; Han, Jingwen^1 ; Hu, Fangkai^1

Key Lab of Smart Grid, Xi'An Jiaotong University, Shanxi Xi'an

710049, China^1

关键词: Balancing strategy;    Capacitor voltages;    Computational formula;    Control strategies;    Current circuits;    DC voltage control;    Simulation model;    Uncontrolled charging;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/486/1/012005/pdf
DOI  :  10.1088/1757-899X/486/1/012005

来源: IOP

【 摘 要 】

This paper designs the control strategies and start procedure of MMC-HVDC. The start procedure consists of three stages, uncontrollable charging stage, controllable charging stage and power-raising stage. The current circuit is analysed and the equivalent circuit is obtained in uncontrolled charging stage. The computational formula of current-limit resistor is obtained in the uncontrollable stage. Two different control strategies to further charge the capacitors to the rated voltage in controllable charging stage are designed. Strategy one makes use of DC voltage control and balancing strategy of capacitor voltage while Strategy two divides the capacitors of one arm into two groups. In power-raising stage, to avoid the impact of power step, slope control is used in power outer loop. Finally, a simulation model is established in the PSCAD/EMTDC. The simulation results show that the effectiveness and rationality of the designed start procedure and control strategies.