Impact of Inertia Control of DFIG-Based WT on Electromechanical Oscillation Damping of SG

Doubly fed induction generator (DFIG)-based wind turbines (WTs) occupy a high penetration in power systems and are being required to emulate inertia response as synchronous generators (SGs). Therefore, it is of value to study the impact of inertia control of DFIG-based WT on electromechanical oscillation damping (EOD) of SG. However, relevant studies that are mainly based on eigenvalue analysis method are not enough and general mechanism study is still lacking. This paper studies the impact rules and mechanism of inertia control parameters (proportional constant and time constant) of WT on EOD of SG with a novel approach. First, linearized model of WT under inertia control is derived based on motion equation concept, which can explicitly describe the external characteristic of WT. From the model, it is clear that the proportional constant determines the inertia characteristic of WT, while time constant has decisive effect on the damping characteristic. Then, by interaction analysis based on motion equation models of both SG and WT, the impact rules and mechanism of inertia control parameters on EOD of SG are explained clearly. Besides, since variable inertia control parameters mean variable inertia and damping coefficients of WT, the impact mechanism can be understood from a general perspective.