A Modified Power System Frequency Response Model Incorporating DFIG Primary Frequency Control Dynamics

Wind turbines (WTs) provision of frequency support has become a must due to the reduction of system inertia caused by their replacement of conventional synchronous generators (SGs). The addition of frequency control complicates WT's frequency response, which hinders power system’ planning and operation for the assurance of frequency stability. To address this issue, the paper takes doubly-fed induction generator (DFIG) based WT as an example, and proposes a modified power system frequency response (SFR) model. Firstly, allowing for the mechanical and control behavior of DFIG electromechanical dynamics, a synthetic motion equation model is built to explicitly characterize its inertia and damping characteristics. Then, considering system power balance relation, a modified SFR model is constructed by inserting the DFIG submodule. And lastly, time-domain simulation is conducted in Matlab/Simulink to verify the accuracy of the proposed model.