Fault-Ride-Through Schemes of Grid-Interfaced DFIG: A comparative study under Symmetrical Grid Faults

The stabilized operation of Doubly Fed Induction Generator (DFIG) during symmetrical faults is a demanding problem for power system engineers. Transient peaks, oscillations, and higher-order frequency harmonics in DC link voltage and rotor circuitry will lead to the violations of the grid-code objectives during grid faults. Control actions must be taken to ensure safe operation of the Wind Energy Conversion System (WECS) during voltage sags/dips or short-circuit conditions without affecting system reliability. Based on the analysis, we propose a hybrid Fault-Ride-Through (FRT) strategy, considering grid-code specifications and converters control functions. Our work also presents a comparative and critical analysis of active FRT schemes under symmetrical faults. Moreover, our work discusses the effect of voltage and current parameters on the steady-state performance and stability of WECS. Furthermore, we analyze transient response of various performance parameters for the comparison of aforesaid schemes, such as rotor voltages and currents, DC link voltage, electromagnetic torque, active and reactive power support, and rotor speed. We used IEEE 5 Bus System interfaced with 9MW DFIG-Wind Turbine (WT) for the FRT performance evaluation in MATLAB/Simulink.