Frequency regulation and AGC in isolated systems with DFIG-based wind turbines

Traditionally, wind turbine generation does not participate in frequency regulation services in power systems. With increasing penetration of wind energy, system operators are demanding more and more participation of wind turbines in the ancillary services especially in frequency regulation provisions. Doubly fed induction generators (DFIGs), with their ability to deliver power with different mechanical speed, and the ability to instantly reduce speed, and release the stored mechanical energy is able to support conventional generators in regulating system frequency. This helps reduce the frequency dip efficiently when the DFIG controller is optimally tuned. This paper examines the role of DFIGs, in frequency regulation and control with different levels of wind penetration into the system. A dynamic model of the power system with conventional generator and DFIG-based wind turbines in single area frequency control is developed, and a parameter optimization method is used to tune the controllers of the DFIG so as to improve the dynamic response of the system.