A Dynamic Equivalent Method for the Offshore Wind Power Farm Based on Operation State

For the purpose of improving the efficiency of small signal analysis and equivalent analysis in the large-scale offshore wind power farm, a dynamic equivalent method based on the operation states is proposed in this paper. Firstly, the dynamic model of multi-infeed wind power farm in the global coordinate is derived for the small signal stability analysis, and then the characteristic equation of the system is formed. Secondly, the characteristic equation is further simplified to a low-order sum form by eigenvalue decoupling method. Then, we can divide and aggregate the converters in the offshore wind power farm based on the numerical comparison process between the eigenvalues of devices and the system’s equivalent eigenvalues under the dominant modes. Further, the equivalent parameters of the equivalent model can be obtained according to the critical conditions. Finally, the effectiveness of the dynamic equivalent method for offshore wind power farm is verified by the eigenvalue analysis and the time domain simulation.