  This paper presents a closed-loop controller for wind farms to provide active
power control services using a high-fidelity computational fluid dynamics based
wind plant simulator. The proposed design enhances power tracking stability and
allows for simple understanding, where each turbine is considered as a pure
time-delay system. The paper investigates the control performance with
different nominal power distributions in a fully waked condition and limited
power availability. Results demonstrate the improvement in power production
obtained by closing the control loop, compared to greedy operation.
Additionally, power tracking capabilities are enhanced with a nominal power
distribution favored by axial-induction, as well as the occurrence of turbine
saturation and the distribution of loads.
