Subsynchronous oscillation of large DFIG-based wind farms integration through MMC-based HVDC

With rapid development of offshore wind power and modular multilevel converter-based high-voltage DC transmission (MMC-HVDC), subsynchronous oscillation (SSO) phenomena might occur due to the interaction between wind farms and MMC-HVDC system. This paper focuses on the SSO of DFIG-based wind farms integration through MMC-HVDC system, and the mechanism of distribution and propagation of SSO in MMC-HVDC system will be revealed. The control scheme for SSO current suppression is given from the perspective of converter control in MMC-HVDC system. Both the theoretical analysis results and the proposed SSO current mitigation strategy are validated by the simulation results.