An Improved Pitch Control-Based Strategy for Creating Power Reserve in Wind Turbines

Abstract

An improved pitch-control based frequency control strategy is presented that enables wind turbines to maintain an active power reserve for primary frequency support across the entire wind-speed operating range. Using $C p(\lambda, \beta)$ characteristics, the proposed approach deliberately shifts the turbine operating point away from the maximum power point to create a reserve that can be dispatched for frequency support when required. The strategy maintains reserve availability under varying wind conditions while respecting turbine operational limitations. To assess its performance, the control strategy is implemented on a 5-MW reference wind turbine model and evaluated using Simulink and OpenFAST. For analysis, realistic $C p(\lambda, \beta)$ characteristics derived from aeroelastic simulations are employed, thereby accounting for structural flexibility effects of the turbine. Simulation results indicate that, unlike conventional approaches whose reserve capability is constrained by generator speed limits, the proposed strategy provides the required active power reserve across the operating range. Consequently, the wind turbine can reliably participate in primary frequency control.