An Active Power Control System for Wind Turbines Capable of Primary and Secondary Frequency Control for Supporting Grid Reliability

Wind energy is producing a larger share of power on many utility grids as more wind turbines are installed, providing motivation for wind turbines to provide ancillary services that are necessary for power grid reliability. The ancillary services considered in this paper consist of actively controlling the power output of the wind turbines to track power set-point commands, participate in frequency regulation, and provide frequency response. This paper focuses on the development of a wind turbine control system that is capable of varying the turbine’s active power output upon receiving de-rating power set-point commands, manual power commands, and automatic frequency regulation commands to meet the system operators’ needs in below-rated and above-rated wind speeds. The turbine is de-rated by operating at a higher than optimal tip speed ratio, storing additional inertia in the rotor, which can be used to assist in frequency regulation by providing a primary response to fluctuations in the grid frequency.