Comparison and Testing of Equivalent Modeling Methods for Wind Farm Composed of Doubly-Fed Induction Generators

For analyzing the power system with high penetration of wind power, it is important to establish accurate models of wind turbines and wind farms, which is a basic and important work. In the analysis of wind power grid integration, it is necessary to aggregate the equivalent value of the wind farm into one or a few wind turbines. At present, there are two commonly used equivalence methods: current source multiplication (commonly used in commercial software) and full dynamic aggregation method. The former achieves wind farm equivalence by multiplying the output current of a single wind turbine generator, while the latter dynamically aggregates the wind farm into one or several large wind turbine generators. There is still a lack of research on the differences between the two. Based on the actual wind farm structure, this paper studies the electrical characteristics of steady-state operation and transient fault ride through operation using single machine dynamic aggregation method and current source multiplication method separately, and compares the equivalent simulation results with the detailed wind farm simulation results. The equivalent accuracy of the single machine aggregation method and the current source multiplication method is calculated to provide a reference for method selection in wind farm equivalent modeling.