Pitch Angle Centralized Optimization Strategy for Wind Farm considering Fluctuation Range of Wind Speed of Nonpitch Regulation

With the increasing proportion of wind power integrated into the grid, wind turbines need to accurately respond to power commands issued by the grid and actively participate in the automatic generation control. To reduce the drastic pitch angle change triggered by frequent touching of the rotor speed boundary in the process of wind turbines responding to power commands, the existing researches have proposed the fluctuation range of wind speed of nonpitch regulation, which makes the rotor speed within the variable speed range as much as possible by proactively setting the reference of pitch angle to match the predict wind speed fluctuation. However, the above studies are limited to the independent optimization at the turbine aspect, and when they are applied to wind farm, the additional pitch angle action will still occur in some turbines due to the wake effect. To address this problem, this paper firstly analyses the mismatch between the corresponding fluctuation range of wind speed of nonpitch regulation and the actual wind speed when each turbine is optimized independently due to neglecting the wake effect between the upstream and downstream turbines. And this is the key reason why the existing methods still have large pitch angle action when applied to wind farm. On this basis, this paper proposes a pitch angle centralized optimization strategy based on the improved sparrow search algorithm to determine the pitch angle set of all wind turbines that minimize the amount of pitch angle action of the wind farm. The effectiveness and superiority of centralized optimization are illustrated by the Matlab/Simulink case.