Low-Voltage Ride Through Strategy for MMC With Y₀/Y₀ Arrangement Transformer Under Single-Line-to-Ground Fault

IEEE Access

Bin Lin¹  Rui Xie¹  Qing Chen¹  Xiaohe Wang¹  Xu Cai² 

[1] Key Laboratory of Far-Shore Wind Power Technology of Zhejiang Province, Hangzhou, China;Wind Power Research Center, Shanghai Jiao Tong University, Shanghai, China;

关键词: Modular multilevel converter (MMC);    grid fault;    high-voltage direct-current (HVDC);    low-voltage ride through (LVRT);   

DOI  :  10.1109/ACCESS.2021.3073950

来源: DOAJ

【 摘 要 】

In the offshore wind farm high-voltage direct-current (HVDC) system, the power delivery capability of the onshore modular multilevel converter (MMC) decreases severely under grid fault, which makes the DC-bus voltage increase rapidly and threatens the safe operation of the system. This paper proposes a low-voltage ride through (LVRT) strategy for MMC with $\text{Y}_{0}/\text{Y}_{0}$ arrangement transformer under single-line-to-ground (SLG) fault. The influence of different transformer arrangements to the MMC under SLG fault is analyzed. On this basis, a power delivery capability enhanced method is proposed for MMC with $\text{Y}_{0}/\text{Y}_{0}$ arrangement transformer to take advantage of its control ability on zero sequence current. In addition, an optimized LVRT strategy based on resonant controller is proposed, which has simple control structure and can ride through the SLG fault without DC chopper. The offshore wind farm MMC-HVDC simulation system is established in PSCAD/EMTDC and simulation studies are conducted to validate the effectiveness of the proposed LVRT strategy.

【 授权许可】

Unknown