Dominant mode and participation factor analysis of sub-synchronous oscillation of wind power connected to weak transmission end of the flexible HVDC system
In the scenario where wind power is connected to the weak transmission end of flexible HVDC system, the interaction between power electronic equipments may cause sub-synchronous oscillation. This paper focuses on the small-signal modeling and stability analysis of wind power connected to the weak-end flexible HVDC transmission system, and carries out the following work: the DC voltage time scale model of the double-fed wind turbine connected to the weak-end flexible HVDC transmission system is established, which fully reflects the sub-synchronization coupling between devices in the frequency band; study the dominant mode of sub-synchronous oscillation of the system and the participation factors of each control loop in different physical scenarios, and analyze the influence weight of each control loop in the dominant mode, reveal the influence rule of control loop bandwidth on system sub-synchronous oscillation; the time-domain simulation model is established in MATLAB, and the above stability analysis results are verified. The research results show that the dominant mode of the system sub-synchronous oscillation is closely related to the strength of the sending end grid, the operating point and the control loop bandwidth.