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 rotating machine, comprises a shaft and at least one device for measuring at least the accelerations of the shaft along pitch, yaw and roll axes of the shaft or the angular position of the shaft around the pitch, yaw and roll axes, the or each device being mounted on the shaft

A method for measuring a load on a rotor blade of a wind power plant includes deriving a deflection of the rotor blade from an acceleration value, determining a signal drift component of the deflection by using an absolute value, and determining the load by using the signal drift component and the deflection and material characteristics of the rotor blade. The acceleration value represents an acceleration on the rotor blade, and the absolute value represents an absolute measured value from an absolute sensor on the rotor blade.

The invention relates to a method of reducing oscillations in an offshore wind turbine comprising one or more thrusters, the method comprising determining an oscillation of the offshore wind turbine and operating the one or more thrusters such that the oscillation is reduced. The invention further relates to an offshore wind turbine comprising one or more underwater thrusters, oscillation determination system for determining an oscillation of the wind turbine and a control system for operating the underwater thrusters in response to signals received from the oscillation determination system.

A method for damping vibration in a wind turbine including aerodynamic devices for influencing the airflow flowing from the leading edge of a rotor blade of the wind turbine to the trailing edge of the rotor blade, each aerodynamic device being movable by an actuator between a first protruded configuration and a second retracted configuration is provided. The method includes measuring vibrations in the wind turbine, if the measured vibrations are greater than a threshold within a predefined frequency band, moving a portion of the aerodynamic devices to the second retracted configuration and continuing to measure vibrations, if the measured vibrations are still greater than a threshold within a frequency band, reducing the pitch angle interval of the blade and continuing to measure vibrations, if the measured vibrations are still greater than a threshold within a frequency band, moving all the aerodynamic devices to the second retracted configuration.

A method of operating a wind turbine power generating apparatus including a wind turbine rotor having a wind turbine blade includes: a step of obtaining a load applied to the wind turbine blade; and a step of selecting an operation mode of the wind turbine power generating apparatus on the basis of the load, from among a plurality of operation modes including a normal operation mode and at least one load-suppressing operation mode in which the load applied to the wind turbine blade is smaller than in the normal operation mode.

A method is provided for dampening oscillations in a wind turbine, the wind turbine having a tower 1, a rotor 3 arranged on the tower 1 such as to be able to rotate about an X axis, and a plurality of blades 4 with adjustable pitch mounted on the rotor. The method includes monitoring the fore-aft oscillation of the tower 1 in the direction of the X axis, at the 2nd or a higher bending mode frequency; determining a compensating torque to be applied by the rotor 3 to the tower 1 of the wind turbine about a Y axis, which is horizontal and at right angles to the X axis, for at least partly dampening the oscillation at the 2nd or higher bending mode frequency; determining for each rotor blade 4 of the wind turbine an adjustment of the pitch angle suitable to generate the compensating torque about the Y axis; and adjusting the pitch angle β1, β2, β3 of at least one of the individual blades 4 to generate at least part of the compensating torque.

A vibration sensor (5) mountable to a wind turbine generator for detecting excessive vibration of the wind turbine generator, the sensor comprising a pendulum having a pendulum bob (25) of pre-determined mass coupled to a detection switch (10), the detection switch arranged to detect oscillation of the pendulum exceeding a predetermined oscillation threshold; said pendulum bob selectively adjustable along said pendulum so as to vary the oscillation threshold of said sensor; wherein the sensor is arranged to exceed the oscillation threshold on receiving a forced vibration corresponding to a vibration threshold of the wind turbine generator.

The invention relates to a method for the individual pitch control of the rotor blades of a wind turbine. The method comprises: measuring an acceleration by means of an acceleration sensor in a rotor blade of the wind turbine; high-pass filtering of a signal of the acceleration sensor in order to determine a time-variant variable; and setting the pitch of the first rotor blade of the wind turbine using the time-variant variable, said pitch setting being part of an individual pitch control.

The present invention relates to control of a wind turbine where nacelle vibration is reduced by use of blade pitching. The nacelle vibrations are reduced based on a position signal of the nacelle. A pitch signal is determined based on the position signal and applied to the pitch-adjustable rotor blades in order to reduce nacelle vibration.