An Integrated Electromechanical Model of the Fixed-Speed Induction Generator for Turbine-Grid Interactions Analysis

When wind turbine is connected to the power grid, the turbine-grid interactions restrict its lifespan and produce adverse effects to the grid. Electrical or mechanical oscillations caused by turbine-grid interactions could gradually be weakened or amplified seriously at a certain frequency. This article discusses all types of interactions between a wind turbine and the grid and the influence of the initial operating point, the parallel capacitor, and the series capacitor on the stability of system. Firstly, an integrated dynamic electromechanical model of a single fixed-speed induction generator (FSIG) wind generation system is derived based on the small signal model of each element. Then, a method of stability analysis based on Kharitonov theorem is introduced. Then, the model details the frequency and damping ratio of oscillation mode and classifies those modes' interactions according to participation factors, followed by time domain simulations by the single FSIG generation system to testify the results. Finally, the article studies all the oscillation modes when the initial operating point, the parallel capacitor, or the series capacitor change in the integrated model, which can be verified by Kharitonov polynomials. The indicative findings help to design the damping control to mitigate turbine-grid interactions.