Sub/Super-Synchronous Oscillation Analysis and Impedance Optimization Design of Wind Power VSC-HVDC Interconnected Systems

With the continuous increase in the proportion of new energy power generation, flexible high-voltage direct current (HVDC) transmission has become an important solution for the large-scale delivery of new energy. However, the dynamic interaction of the control loops between the wind farm and the sending-end flexible HVDC system is likely to trigger a negative damping effect in the sub/super-synchronous frequency band, which in turn endangers the stable operation of the power system. In this paper, an impedance model of MMC-HVDC for wind farm integration considering frequency coupling is established. Based on this model, critical control parameters affecting MMC and wind turbine dynamics are quantitatively characterized through impedance sensitivity indices, identifying dominant stability influencers in sub/super-synchronous bands. Furthermore, An enhanced stability assessment methodology is proposed, deriving parametric stability boundaries via the improved Generalized Nyquist Criterion (GNC), establishing mathematical constraints for control parameter and impedance optimization. Finally, based on the MATLAB/Simulink simulation model, the correctness and effectiveness of the theoretical analysis are verified.