Pitch control for improving the low-voltage ride-through of wind farm

One of the major concerns for the stability of power systems including large amount of wind turbine generators is how to improve the Low-Voltage Ride-Through (LVRT) capability of wind turbine generators during voltage dip occurring in power networks. In order to achieve LVRT improvement, this paper proposes a new method of pitch angle control for induction-generator-type of wind turbine. If the turbine rotor speed can be reduced quickly during voltage dip so as not to rise over the maximum speed, then the sudden disconnection of wind turbine generator can be avoided. The proposed pitch control system can modify the pitch angle in the short response time by the coordination of protective relay for wind turbine. The simulation study shows that the proposed pitch control system is effective to enhance LVRT capability of induction-generator type of wind turbine.