A monitoring system for monitoring a time period of a locking state of a rotor of a wind turbine includes at least one motion sensor and at least one computing unit, wherein the computing unit is confiugered to receive at least one motion measurement from the at least one motion sensor and wherein the computing unit is configured to determine whether the rotor may remain in the locking state or the rotor should be unlocked based on the at least one motion measurement. A wind turbine having the monitoring system and a method for monitoring a time period of locking state of a rotor of a wind turbine is also provided.

Disclosed is a method of establishing a wake management of a wind farm. The method comprises acts of monitoring one or more wake conditions using one or more sensors from one or more wind turbine generators (WTGs); and establishing a wake management of the wind farm as a function of the wake conditions. Disclosed is also a method of optimising operation of a wind turbine park based on wake management and a system for generating wake management.

Provided is a method of monitoring the structural integrity of a supporting structure of a wind turbine, which method includes the steps of determining a fore-aft tower oscillation frequency; determining a side-to-side tower oscillation frequency; computing a working structural indicator value from the fore-aft tower oscillation frequency and the side-to-side tower oscillation frequency; comparing the working structural indicator value to a reference working structural indicator value; and issuing an alarm if the difference between the working structural indicator value and the reference structural indicator value exceeds a predefined threshold. Also provided is a system for monitoring the structural integrity of a supporting structure of a wind turbine, a wind turbine, and a computer program product for carrying out the steps of the inventive method.

A method for detecting a failure condition in one or more components of a wind turbine is provided. The method includes actuating, via a controller, an impact device to generate a vibration having a vibration frequency and a vibration magnitude in the one or more components. The method further includes receiving data indicative of the vibration frequency and the vibration magnitude from a sensor communicatively coupled to the controller. The method further includes determining, via the controller, whether the data indicative of the vibration frequency and/or the vibration magnitude is outside of a predetermined vibration range for the one or more components.

The invention relates to a sensor arrangement for use on a wind turbine. The sensor arrangement comprises a rotor blade-related sensor, which is arranged in/on a rotor blade, and a non-rotor blade-related sensor, wherein the sensor signals, which are associated with the rotor blade-related sensor, are processed by fusion with the sensor signals which are associated with the non-rotor blade-related sensor. The invention also relates to a method for operating a wind turbine.

The present invention relates to a rotor control system for actuating pitch of pitch adjustable rotor blades of a wind turbine in order to reduce edgewise blade vibrations. The system comprises a pitch actuation unit being arranged to receive a torsional vibration signal and apply a filter to the torsional vibration signal to couple the torsional vibration signal to an edgewise vibration of the rotor blades. An m-blade coordinate transformation, such as the Coleman transformation, is applied to the filtered torsional vibrational signal to obtain pitch modification signals.

Provided is a system for determining an amount of oscillating movement of a wind turbine, the wind turbine including a tower, a non-rotating upper part supported by the tower, a rotor having a rotor axis, and a generator for generating electric power. The system includes (a) a sensor unit adapted to provide a rotor speed signal indicative of a rotational speed of the rotor relative to the non-rotating upper part, (b) a filtering unit adapted to, based on the rotor speed signal provided by the sensor unit, provide a filtered signal including information associated with an oscillating movement of the wind turbine, and (c) a processing unit adapted to determine the amount of oscillating movement based on the filtered signal provided by the filtering unit. Furthermore, a wind turbine and a method are described.

The present invention relates to a wind turbine and a method of operating a wind turbine for reducing edgewise vibrations, wherein the wind turbine comprises a wind turbine control system having at least one vibration sensor for measuring the edgewise vibrations and a controller for receiving the vibration signal from the vibration sensor. The sensor unit is preferably an accelerometer arranged in a stationary frame of reference. The controller determines at least one whirling mode frequency and the vibration level thereof. The controller initiates a corrective action if the measured vibration level exceeds a threshold value. The corrective action is preferably an adjustment of the pitch angle of the wind turbine blades which in turn dampens the edgewise vibrations.

Pitch control system (1) for at least one rotor blade (17) for a wind turbine comprising a nacelle (16), as well as a hub (15) both place on the top of a tower (18) and at least one rotor blade (17). The system comprises at least one electrical pitch drive system (3) each drive system (3) is connected to a rotor blade (17) and an electrical pitch motor (2). The electrical pitch drive system(s) (3) is/are adapted to communicate with units comprising the motor(s) (2) for pitching the rotor blade (17) it is attached to and in accordance with inputs registered from a first sensor and a second sensor (20). Each electrical pitch drive system (3) comprises a gyroscope (22) adapted to register an angle value of the longitudinal axis of the rotor blade (17) with respect to the gravity. A processor is adapted to calculate the position of the rotor blade (17) based on said values.

A method for operating a wind turbine, an associated wind turbine, and an associated wind park are provided. The wind turbine has a tower with tower loads acting thereon and an aerodynamic rotor which generates a rotor thrust. The method has a step of reducing the rotor thrust. The reduction of the rotor thrust is performed while considering the effect of the reduction of the rotor thrust on the tower loads. Thus, the reduction of the rotor thrust is avoided in cases which result in undesirable or even counter-productive effects on the tower loads.