A single-end protection scheme for hybrid MMC HVDC grids considering the impacts of the active fault current-limiting control

Yang, Saizhao and Xiang, Wang and Zhou, Meng and Zuo, Wenping and Wen, Jinyu (2020) A single-end protection scheme for hybrid MMC HVDC grids considering the impacts of the active fault current-limiting control. IEEE Transactions on Power Delivery. ISSN 0885-8977 (https://doi.org/10.1109/TPWRD.2020.3017895)

[thumbnail of Yang-etal-IEEE-TOPD-2020-A-single-end-protection-scheme-for-hybrid-MMC-HVDC]
Preview
Text. Filename: Yang_etal_IEEE_TOPD_2020_A_single_end_protection_scheme_for_hybrid_MMC_HVDC.pdf
Accepted Author Manuscript

Download (1MB)| Preview

Abstract

In the hybrid modular multilevel converter (MMC) based high voltage direct current (HVDC) systems, the fault current can be actively suppressed by the converter itself, which endows a smaller requirement for current-limiting reactors (CLR) and a larger time margin for fault detection algorithms, comparing with the half-bridge MMC. But the robustness to fault resistance and noise disturbance of existing boundary protection schemes will be deteriorated with small CLRs. Moreover, the fast response of the fault current-limiting control will change the output DC voltage of hybrid MMC, which affects the fault characteristics and may cause mal-operation of existing protection algorithms. Thus, a single-end protection scheme considering the impacts of the active current-limiting control is proposed for the hybrid MMC based DC grids. The traveling-wave characteristics under different fault stages are analyzed to evaluate the impacts of the fault current-limiting control. In addition, a coordination protection strategy versus different fault conditions is adopted to improve reliability. Various cases in PSCAD/EMTDC are simulated to verify that the proposed method is robust to fault resistance, fault distance, power reversal, AC faults, and immune to noise.