A Novel Control Strategy for DVR to Improve Voltage Profile in Wind Farm

Power quality is one of major concerns in the present era. It has become important, especially, with the introduction of sophisticated devices, whose performance is very sensitive to the quality of power supply. To improve the power quality, custom power devices are used. The device considered in this work is DVR. This work presents a control strategy for a DVR to improve the stability in wind farms based on SCIG. The DVR controller is designed to work under unbalanced conditions, which allows overcoming most faults in the power grid. The proposed strategy is capable of balancing voltages at wind farm terminals obtaining several advantages. Firstly, negative-sequence currents are eliminated; thus, overheating, loss of performance, and decreasing of generator useful life are avoided. Secondly, by nullifying negative sequence voltages, 2ω pulsation in the mechanical torque is prevented, reducing high stress in the turbine mechanical system, especially in the gearbox. The power system, DVR converter, and controller were implemented in the Sim power Systems blockset of SIMULINK/MATLAB®.