A method for setting a fully or partially built wind power installation having a rotor having a plurality of rotor blades whose blade angle can be adjusted, wherein the wind power installation can take on variable operating situations, and each operating situation is characterized by a combination of settable installation settings of the wind power installation and environmental conditions that can be captured, with the result that an operating situation can be set for given environmental conditions by setting the installation settings, and operating situations that should be avoided and/or suitable operating situations are stored in a memory by storing a combination of environmental conditions and installation settings as a combination to be avoided for an operating situation that should be avoided in each case, and/or storing a combination of environmental conditions and installation settings as a suitable combination for a suitable operating situation in each case, and, to avoid operating situations that should be avoided, environmental conditions are captured and, depending on the captured environmental conditions and the stored combinations to be avoided and/or suitable combinations, installation settings of the wind power installation are selected and set such that installation settings of stored combinations to be avoided are avoided, and/or installation settings are selected from stored suitable combinations.

The present disclosure is related to methods (400; 500; 600) configured for detecting the state of a wind turbine blade (22). The methods (400; 500; 600) comprising receiving (401; 501) load signals from a wind turbine blade (22), determining (402; 503) an energy of the load signal in a first and second frequency and comparing (403; 504) said energy to generate a flag signal if the energy in the first frequency is smaller than the energy in the second frequency. A control system (600) suitable to detect the state of a wind turbine blade (22) is also provided, as well as wind turbines (10) including such a control system (600).

A method for tracking a gear tooth meshing angle of a gearbox of a wind turbine is disclosed. An initial reference virtual gear tooth meshing angle of the gearbox is selected, and an angular position of a high speed shaft and/or a low speed shaft of the gearbox is monitored. A virtual gear tooth meshing angle relative to the reference virtual gear tooth meshing angle is estimated, based on the monitored angular position of the high speed shaft and/or the low speed shaft and on information regarding topology of the gearbox. A number of full rotations of the high speed shaft and/or the low speed shaft which corresponds to an integer number of full periods of gear meshing of the gearbox is calculated, and the reference virtual gear tooth meshing angle is reset each time the high speed shaft and/or the low speed shaft has performed the calculated number of full rotations. The estimated virtual gear tooth meshing angle is applied to a periodic noise signal of the wind turbine.

A method for controlling operation of a generator for a wind turbine is disclosed. At least one amplitude of a harmonic in the gearbox vibrations is determined. A torque modulating signal for the generator is generated. A phase angle and the amplitude are adjusted during operation of the generator, until a minimum in amplitude of a resultant vibration is reached, thereby obtaining an adjusted torque modulating signal. The adjusted torque modulating signal is injected into the generator, resulting in the resultant vibration of vibrations of the gearbox and vibrations of the generator, corresponding to the harmonic in the gearbox vibrations, being reduced.

Techniques are provided for monitoring blades of a wind turbine by actively promoting blade vibrations by imposing a pitch actuation signal. A method of operating a wind turbine is disclosed where for each blade of a wind turbine, vibrations of the blade are actively promoted by imposing a pitch actuation signal to the pitch actuator, and at least one parameter relating to the blade vibration is determined.

The present disclosure is related to methods (400; 500; 600) configured for detecting the state of a wind turbine blade (22). The methods (400; 500; 600) comprising receiving (401; 501) load signals from a wind turbine blade (22), determining (402; 503) an energy of the load signal in a first and second frequency and comparing (403; 504) said energy to generate a flag signal if the energy in the first frequency is smaller than the energy in the second frequency. A control system (600) suitable to detect the state of a wind turbine blade (22) is also provided, as well as wind turbines (10) including such a control system (600).

A method for controlling operation of a generator for a wind turbine is disclosed. At least one amplitude of a harmonic in the gearbox vibrations is determined. A torque modulating signal for the generator is generated. A phase angle and the amplitude are adjusted during operation of the generator, until a minimum in amplitude of a resultant vibration is reached, thereby obtaining an adjusted torque modulating signal. The adjusted torque modulating signal is injected into the generator, resulting in the resultant vibration of vibrations of the gearbox and vibrations of the generator, corresponding to the harmonic in the gearbox vibrations, being reduced.

A method is for controlling a wind turbine. The wind turbine has a tower, a nacelle, a rotor with at least two rotor blades and a yaw system with at least one yaw drive configured to rotate the nacelle about a vertical axis of the tower (yaw axis). A control signal for the at least one yaw drive depends on at least one signal indicative of the wind direction. The control signal for the at least one yaw drive further depends on at least one value indicative of a vibration mode of the rotor blades.