The present disclosure relates to methods for determining reliability of an azimuth measurement system in a wind turbine. The methods comprise measuring loads with load sensors during operation and determining in-plane moments with rotor rotational speed frequency of one or more blades based on the measured loads. The methods further comprise measuring an azimuthal position of a wind turbine rotor. The method also comprises determining that the azimuth measurement system has reduced reliability if an angular phase of the in-plane moments deviates from the measured azimuthal position by more than a first threshold value. The present disclosure also relates to wind turbine systems incorporating azimuth measurements and methods for on-line determination of correct functioning of azimuth sensors.

An information generating device includes a control unit for causing a motor to rotate a pinion gear meshing with a ring gear while a predetermined braking force is applied to brake rotation of a turnable part of a wind turbine, thereby causing a fastening part to deform, where the fastening part is provided to fixedly attach the motor to a target part, a deformation amount obtaining unit for obtaining an amount of deformation experienced by the fastening part, and an information generating unit for generating correlation information indicating a correspondence between a driving torque of the motor and the amount of deformation experienced when the driving torque is used to rotate the motor.

The invention relates to a method for identifying an asymmetrical extreme load which is caused by a gust of wind and acts on a wind power installation, wherein the wind power installation has a rotor having at least three rotor blades; the rotor blades are adjustable in terms of the blade angle thereof; and the rotor by way of the rotor blades thereof sweeps a rotor field; and the method comprises continuous detecting of a blade load for each rotor blade; ascertaining for at least one sector of the rotor field at least one temporal sector load profile from blade loads detected of different rotor blades with the same azimuth position, said sector load profile describing a temporal profile of a load on the rotor blades in the sector and containing a profile extrapolated for a future temporal period, wherein the blade loads are detected or taken into account at successive detection time points which are spaced apart by a partial period in which the rotor rotates further by one rotor blade, so that successive blade loads are detected or taken into account for the respective sector; and checking in terms of expecting an extreme load as a function of the at least one sector load profile.

The disclosure relates to a method for operating a wind turbine wherein the method includes: operating the wind turbine over an operating period in accordance with a control strategy, providing one or more input values representing a load acting on at least one component of the wind turbine and providing uncertainties of the input values, determining, based on the input values, an aggregated load value representing an aggregated load acting on the at least one component of the wind turbine over an aggregation period, determining, based on the uncertainties of the input values, an uncertainty of the aggregated load value, determining a statistical load aggregate from the aggregated load value and the uncertainty of the aggregated load value, adjusting the control strategy based on the statistical load aggregate. The disclosure further relates to a wind turbine and a wind farm configured to perform the above method.

Control of a multi-rotor wind turbine system. A local controller is arranged for each wind turbine module and implementing a local model predictive control (MPC) routine. A central controller is arranged to determine a set of operational constraints of the wind turbine modules. Based on a current operational state of the wind turbine module and the set of operational constraints, one or more predicted operational trajectories are calculated and used for controlling the wind turbine module.

A method of controlling a wind turbine is provided, comprising identifying an out-of-vertical load acting in a first direction on the wind turbine. A direction of a wind load acting on the wind turbine is determined. If there is a degree of alignment between the direction of the wind load and the first direction, the wind turbine is controlled to reduce the wind load.

A method for reducing extreme loads acting on a component of a wind turbine includes measuring, via one or more sensors, a plurality of operating parameters of the wind turbine. Further, the method includes predicting at least one blade moment of at least one rotor blade of the wind turbine based on the plurality of operating parameters. The method also includes predicting a load and an associated load angle of the at least one rotor blade as a function of the at least one blade moment. Moreover, the method includes predicting a pitch angle of the at least one rotor blade of the wind turbine. In addition, the method includes generating a load envelope for the component that comprises at least one load value for the pitch angle and the load angle. Thus, the method includes implementing a control action when the load is outside of the load envelope.

The invention is about a method for controlling a wind turbine with a variable rotor area. The wind turbine comprises a rotor with one or more rotor blades which are arranged hinged at an adjustable pivot angle, where the variable rotor area depends on the pivot angle, and where the pivot angle is adjustable dependent on a variable pivot force provided by a pivot actuator. The method comprises determination of a maximal pivot force based on the input operational parameter which relate to an actual load or a predicted load of the wind turbine, determining a desired pivot force based on a desired operational performance of the wind turbine, and determining a pivot force set-point to be applied to the pivot actuator based on the desired pivot force so that the pivot force set-point is equal to or below the maximal pivot force.

A method for operating a wind turbine for generating electrical power from wind, wherein the wind turbine has an aerodynamic rotor with a rotor hub and rotor blades of which the blade angle is adjustable, and the aerodynamic rotor can be operated with a variable rotation speed, and the wind turbine has a generator, which is coupled to the aerodynamic rotor, for the purpose of generating a generator power, wherein the generator can be operated with a variable generator torque, comprising the steps of: determining a loading variable which indicates a loading on the wind turbine by the wind, and reducing the rotation speed and/or the generator power in a loading mode depending on the loading variable, wherein at least one force variable that acts on the wind turbine is used for determining the loading variable or as the loading variable.

The present disclosure relates to a method for operating a wind power installation, in particular for identifying unusual oscillation events, and an associated wind power installation and a wind farm. The method comprises the steps of: providing a parametrized limit for a value of an observed oscillation of a component of the wind power installation; determining a current limit from the parametrized limit taking account of at least one current ambient parameter, in particular an ambient parameter that is indicative for the current incident flow; determining a current value of the observed oscillation of the component; comparing the current value of the observed oscillation of the component with the current limit; and operating the wind power installation on the basis of the result of the comparison.