Development of a novel method for the correction of the nacelle wind speed in stall-controlled wind turbines

Accurate estimation of the oncoming wind is key to ensure an accurate control of any wind turbine. The wind speed is commonly measured with an anemometer located on the nacelle; hence, the measurement is influenced by the rotor and the nacelle itself and needs to be corrected so as not to incur inaccurate energy yield assessments. This study introduces an innovative method for correcting the nacelle wind speed in stall-controlled wind turbines. The development of the method has benefitted from the unique possibility of exploiting two datasets containing 10-minute averaged wind data from two identical EUNICE EW16 wind turbines and a meteorological mast located at the same site. The innovative method is systematically compared with the Nacelle Transfer Function outlined in the IEC 61400-12-2, serving as a benchmark for evaluation. The high accuracy and simplicity of the proposed method make it particularly suitable for the optimization of wind turbine performance in industrial applications. Moreover, an accurate estimation of the incoming wind speed can enable innovative control techniques, such as those based on Tip-Speed-Ratio (TSR) tracking. This is addressed in the study through simulations by comparing a TSR-Tracking strategy with the most common k-ω2 strategy. The study demonstrated that the TSR-Tracking strategy could be adopted in stall-controlled wind turbines if an accurate estimation of the free-stream wind speed is available.