Automatic Gain Controller for Variable Speed Wind Turbines

This paper presents a novel controller for DFIG based wind parks, designed to achieve more efficient voltage regulation, reactive power compensation and to enhance the transient stability margin of the interconnected power system. The supervisory-secondary voltage control is used to generate the local voltage reference, providing an improved overall voltage profile, while combining an automatic gain controller (AGC) to improve the transient response of the primary control loop. The controller is implemented and tested with a power system comprising of a lumped, fundamental frequency model of a DFIG based wind park, and hydro and diesel generators connected to the electric grid. The performance of the controller was investigated for both steady-state improvements as well as under extreme contingencies to demonstrate its benefits.