A device may receive historical operational data for a mechanical system, such as a rotor blade of a wind turbine. The device may determine one or more quality grades for each of one or more materials of the system, e.g., the rotor blade. The one or more quality grades may be determined by using a data model to process the historical operational data. The data model may be trained using machine learning based on one or both of historical operational data for similar systems, e.g., other rotor blades, and end-of-life (EOL) testing data for the same. The device may determine a recycling recommendation based on the one or more quality grades. The recycling recommendation may include instructions relating to recycling the one or more materials. The device may deliver the recycling recommendation to another device or recipient.

A service life evaluation method and device for a pitch bearing of a wind turbine are provided. The method includes: acquiring a probability density of a pitch driving torque in M historical periods, wherein M is a positive integer; acquiring an angle cumulative value of a pitch angle in each of the M historical periods; determining an equivalent load of the pitch bearing based on the pitch driving torque, the probability density of the pitch driving torque in the M historical periods, and angle cumulative values in the M historical periods; and determining a consumed service life of the pitch bearing based on the equivalent load of the pitch bearing

A method is for operating a wind turbine. The wind turbine includes a nacelle including a nacelle component, in particular a rotor bearing, and a nacelle air flow influencing unit. The nacelle air flow influencing unit is configured to influence an air flow entering, flowing through and/or exiting the nacelle. The method includes: determining an operating condition of the nacelle component, determining a cooling demand of the nacelle component dependent on the determined operating condition of the nacelle component, controlling an operation of the nacelle air flow influencing unit dependent on the cooling demand of the nacelle component to adapt the air flow to the cooling demand of the nacelle component.

A load control method and a load control apparatus for a wind turbine generator system are provided, and the load control method includes: obtaining feature parameters of the wind turbine generator system for load prediction; obtaining a load estimation value of the wind turbine generator system by inputting the obtained feature parameters into a virtual load sensor; adjusting a control strategy of the wind turbine generator system based on the obtained load estimation value. A controller and a computer readable storage medium storing a computer program are further included. With the load control method and apparatus for the wind turbine generator system, a trained virtual load sensor can be used to realize real-time monitoring of the load of the on-site wind turbine generator system, and a reference for adjusting the control strategy can be provided according to the load.

The present disclosure relates to controlling an operation of a wind turbine. A first plurality of extreme load measures indicative of extreme loads experienced by at least part of the wind turbine during the first period of time are determined and a load probability characteristic is then determined based on a statistical analysis of the distribution of the first plurality of extreme load measures. A control strategy for controlling the operation of the wind turbine is then modified based at least in part on a comparison of the load probability characteristic and a design load limit and the wind turbine is then subsequently controlled in accordance with the modified control strategy for a second period of time.

A load mitigation arrangement of a non-mounted rotor blade, includes at least one actuatable lift-modification device arranged on a surface of the rotor blade; a monitor configured to estimate the magnitudes of loads acting on the non-mounted rotor blade; a controller configured to actuate the lift-modification device on the basis of the estimated magnitudes to mitigate the loads acting on the non-mounted rotor blade. Further provided is a rotor blade assembly, and a method of performing load mitigation on a non-mounted rotor blade.

A control arrangement for a variable-speed wind turbine includes a loading analysis module configured to analyse a number of environment values to establish whether the momentary wind turbine loading is lower than a loading threshold when the rotational speed of the aerodynamic rotor has reached its rated value; and a speed boost module configured to determine a speed increment for the rotational speed of the aerodynamic rotor if the wind turbine loading is lower than the loading threshold.

A test rig for testing a blade bearing of a wind turbine blade is provided. The blade bearing includes a first part and a second part that is rotatable about an axial direction with respect to the first part. The test rig includes a bearing support, which is configured to be mounted to the first part of the blade bearing, a shaft element, which is configured to be mounted to the second part of the blade bearing and able to rotate with respect to the bearing support. A test load unit is configured to apply a load in the axial direction to the shaft element. The test load unit includes at least one actuator that is controllable to apply the load.

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).