According to an example aspect of the present invention, there is provided a sensor comprising at least one strut configured to be coupled to a surface of an object at a first end of the strut, a structure connected to a second end of the at least one strut, wherein the structure is V-shaped, U-shaped, curved or arched and configured to be coupled to the surface at both ends, a plurality of cavities positioned along the structure on both sides of the at least one strut, and a plurality of fibre-optic pressure transducers, wherein a single fibre-optic pressure transducer is arranged within each of the cavities, and wherein the sensor is configured such that at least some of the fibre-optic pressure transducers are arranged at different distances from the surface of the object.

A method for protecting a wind turbine from an extreme change in wind direction includes receiving a wind direction and/or a wind speed at the wind turbine. When a change in the wind direction or the wind speed exceeds a predetermined threshold, the method includes determining a margin to stall and/or zero lift of the at least one rotor blade of the wind turbine as a function of an angle of attack or change in the angle of attack at a blade span location of at least one rotor blade of the wind turbine. The method also includes implementing a corrective action for the wind turbine (without shutting down the wind turbine) when the margin to stall and/or zero lift exceeds a predetermined value so as to avoid stall and/or negative lift on the at least one rotor blade during operation of the wind turbine.

The present disclosure provides a method and system for calculating aerodynamic force of a wind turbine airfoil under different turbulence intensities. The method of the present disclosure includes: calculating a lift coefficient and a drag coefficient according to measured wind pressure, performing function fitting to obtain a fitted lift coefficient model and a fitted drag coefficient model at the different turbulence intensities, and selecting a corresponding fitted lift coefficient model and drag coefficient model according to a turbulence intensity on a wind turbine to be measured, to directly calculate a lift coefficient and a drag coefficient for the aerodynamic force of the airfoil.

A method of determining a value of a pitch speed for a pitch actuator of at least one rotor blade of a wind turbine includes: providing a quantity being indicative of a value of a bearing moment of the rotor blade; determining the value of a pitch speed based on the quantity and a reference quantity indicative of a reference value of the bearing moment of the rotor blade such that, if the quantity indicates that the value of a bearing moment of the rotor blade is below the reference value of the bearing moment of the rotor blade, the value of a pitch speed is determined to be above a reference value of the pitch speed.

A method for protecting a wind turbine from an extreme change in wind direction includes receiving a wind direction and/or a wind speed at the wind turbine. When a change in the wind direction or the wind speed exceeds a predetermined threshold, the method includes determining a margin to stall and/or zero lift of the at least one rotor blade of the wind turbine as a function of an angle of attack or change in the angle of attack at a blade span location of at least one rotor blade of the wind turbine. The method also includes implementing a corrective action for the wind turbine (without shutting down the wind turbine) when the margin to stall and/or zero lift exceeds a predetermined value so as to avoid stall and/or negative lift on the at least one rotor blade during operation of the wind turbine.

A method is provided for operation of a wind turbine having rotor blades attached to a hub, wherein a controller compensates for torsionally induced blade twist. The method includes operating the wind turbine according to a rated power output curve and maximum design thrust value, and periodically or continuously detecting for induced torsional twist in the rotor blades. Upon determination of torsional twist being induced in the rotor blades, the method includes adjusting the maximum thrust value in the control program to compensate for the induced twist. The wind turbine controller then controls pitch of the rotor blades as a function of the increased maximum thrust value so that power output of the wind turbine is not unnecessarily limited or increased by the induced twist on the rotor blades.

A method is provided for operation of a wind turbine having rotor blades attached to a hub, wherein a controller compensates for torsionally induced blade twist. The method includes operating the wind turbine according to a rated power output curve and maximum design thrust value, and periodically or continuously detecting for induced torsional twist in the rotor blades. Upon determination of torsional twist being induced in the rotor blades, the method includes adjusting the maximum thrust value in the control program to compensate for the induced twist. The wind turbine controller then controls pitch of the rotor blades as a function of the increased maximum thrust value so that power output of the wind turbine is not unnecessarily limited or increased by the induced twist on the rotor blades.

A method of determining a value of a pitch speed for a pitch actuator of at least one rotor blade of a wind turbine includes: providing a quantity being indicative of a value of a bearing moment of the rotor blade; determining the value of a pitch speed based on the quantity and a reference quantity indicative of a reference value of the bearing moment of the rotor blade such that, if the quantity indicates that the value of a bearing moment of the rotor blade is below the reference value of the bearing moment of the rotor blade, the value of a pitch speed is determined to be above a reference value of the pitch speed.

A method of controlling a wind turbine, the wind turbine comprising: a tower; a rotor-nacelle-assembly (RNA) comprising a rotor and a nacelle, the rotor comprising one or more blades. The method comprises obtaining tilt angle data indicative of a tilt angle of the RNA, yaw angle data indicative of a yaw angle of the RNA, and a thrust of the rotor. Tilt moment data is determined based on the tilt angle data and the thrust, wherein the tilt moment data is indicative of a tilt moment acting on the rotor about a tilt axis. Yaw moment data is determined based on the yaw angle data, wherein the yaw moment data is indicative of a yaw moment acting on the rotor about a yaw axis. A pitch angle of one or more of the blades is controlled based on the tilt moment data and the yaw moment data.