Response and Protection of DFIG System under Grid Fault

The use of doubly fed induction generators (DFIG) in large wind turbines has become quite common over the last few years. However, DFIG are very sensitive to grid disturbances, especially to voltage dips, therefore low voltage ridethrough(LVRT) technology for DFIG becomes one of the critical technology in the uninterrupted operation of wind power generation. In order to help the study of low voltage ride-through(LVRT) technology for DFIG, a detailed thoretical analysis of the dynamic behavior of DFIG during grid voltage drop and recovery has been proposed, and obtained the maximum instantaneous rotor voltage when the voltage drop and the maximum and minimum rotor voltage when voltage recovery, then given the relevant simulation waveform. At last, the method on crowbar design is proposed.