Small Signal Stability Analysis of DFIG Penetrated Multi-machine Power System with Synthetic Inertia Control

In recent times, renewable energy resource based bulk power plants are being implemented in power system and wind energy based farms are one amongst them. The induction machines employed in the wind farms possess different characteristics compared to conventional synchronous generator plants. The behaviour of these induction generators, can affect the stability of power system when they operate in synchronism with synchronous generators. Also, the frequency response of the power system has been deteriorated with integration of converter based wind turbine generators because of their inability to provide natural inertial response. One of the remedies for this can be to operate the doubly fed induction generators (DFIG) as a synchronous generator to provide inertial response during frequency event. In the literature, small signal stability has been analyzed for the SMIB system integrated with the wind farm. This paper offers small signal stability analysis of multi-machine power system integrating DFIG based wind farm. It further analyzes the changes in small signal response and frequency improvement while the DFIGs are operated in order to emulate the synthetic inertia. Detailed modeling of the wind generators and their integration with the multi-machine system is presented in this paper. Eigenvalue analysis has been performed for it and the effect of DFIG based wind farm on the frequency oscillations and damping of the system is discussed.