Investigation of sub-synchronous resonance conditions in dfig-based wind turbines using TCSC

The rapid growth of renewable energy has brought a profound transformation to the energy sector, with wind power emerging as one of the fastest-developing technologies. Doubly-Fed Induction Generators (DFIGs) are widely used in large-scale wind applications due to their high efficiency and controllability under variable wind speeds. However, series compensation applied to enhance transmission capacity may induce sub-synchronous oscillations in the generator-grid interaction, leading to Sub-Synchronous Resonance (SSR).In this thesis, MATLAB/Simulink was employed to conduct comprehensive simulations. The SSR phenomenon was first analyzed without any supplementary control, and subsequently with a Thyristor-Controlled Series Capacitor (TCSC) integrated into the DFIG-based wind farm. The system's response—active and reactive power, DC-link voltage, and rotor speed—was examined under various wind speeds and compensation levels.Finally, a fuzzy logic-based controller replaced the conventional Proportional-Integral (PI) controller within the TCSC structure. Results show that the fuzzy controller effectively damps SSR oscillations and enhances overall system stability. The analysis confirms that the grid-connected DFIG system achieves rapid stabilization, with oscillations efficiently suppressed in a short period.