Simplified Transient Model of DFIG Wind Turbine for COI Frequency Dynamics and Frequency Spatial Variation Analysis

With the high penetration level of renewable power generation, their impacts on the power system frequency dynamics need to be considered, especially the doubly-fed induction generator (DFIG) based wind turbines. By analogy with the synchronous generator, this article proposes the simplified transient model of DFIG wind turbines, which consists of the equivalent circuit model and the equivalent rotor motion model. It provides a viable and tractable way to analytically quantify the contribution of DFIG wind turbines to the post-disturbance frequency, both in the center of inertia (COI) frequency and frequency spatial variation cases. The unique frequency-supporting features of the DFIG wind turbine are discussed. The model implementation at the wind farm level is provided. The correctness of the proposed model is verified by simulation results of a weak power system. The comparison with the existing models on frequency dynamics analysis is discussed.