Active Current-Limiting Control to Handle Overhead Line Fault in DC Grid [柔性直流电网直流线路故障主动限流控制]

作者：Zhou M; Xiang W^*; Lin W; Wen J; Zuo W

来源：Power System Technology, 2018, 42(7): 2062-2072.

DOI：10.13335/j.1000-3673.pst.2018.0117

• Active converter
• Active current-limiting control
• DC grid
• DCCB
• Line fault

To handle line faults in a DC grid, this paper proposed a new method of active current-limiting control (ACLC) based on hybrid MMC. With this active control, breaking capacity requirement of DC circuit breaker (DCCB) will significantly decrease and DC gird investment will be reduced. Firstly, independent controllability of AC/DC voltage of converter is studied. The ACLC control architecture is proposed. To avoid overvoltage of capacitor on each arm during DC fault, a method of dynamically adjusting DC current thresholds is proposed. The ACLC optimization method, i.e., target predetermined control, is put forward. Impact of different controller delay time on the ACLC is analyzed. Transient evolution mechanisms of DC fault current are studied in a single converter system and in DC grid respectively. Finally, validity of the ACLC is verified.

• 单位
  强电磁工程与新技术国家重点实验室; 华中科技大学