Low-Voltage Ride-Through Capability Improvement of DFIG-Based Wind Turbines Using Superconducting Fault Current Limiter

Since the usage of wind energy as a renewable energy source is increasing fast, there is a need to keep wind turbines connected to the grid during different grid faults. In this paper, a simple way for improving low voltage ride-through (LVRT) capability of variable speed wind turbines (WTs) equipped with a doubly fed induction generator (DFIG) is presented. The proposed strategy consists of a series Superconducting Fault Current Limiter (SFCL) with DC link capacitor and an added PID controller to rotor-side converter (RSC) control process and a conventional pitch angle controller. To highlight the proposed technique, a DFIG is considered as a wind turbine generator. The whole system is simulated in Simulink/ Matlab software. The obtained results ensure that this way is effective in decreasing the fault currents and DC link voltage fluctuations. The voltage dip characteristics are discussed in accordance with international standards for wind turbines.