A method for controlling pitching of at least one rotor blade of a wind turbine includes receiving, via one or more position localization sensors, position data relating to the at least one rotor blade of the wind turbine. Further, the method includes determining, via a controller, a blade deflection signal of the at least one rotor blade based on the position data. Moreover, the method includes determining, via a computer-implemented model stored in the controller, a pitch command for the at least one rotor blade as a function of the blade deflection signal and an azimuth angle of the at least one rotor blade.

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.

In a wind turbine comprising a tower supporting a nacelle, at least one blade rotationally attached to the nacelle and having a blade-tip section, a system for measuring the separation distance between the tower and the blade-tip-section of the wind turbine, comprising an indicator stripe on the surface of the blade-tip section, an indicator ring encircling the tower, a camera in the nacelle and positioned such that the blade-tip section and the indicator ring are within the camera's field of view when the blade-tip is at its closest approach position to the tower, the camera digitally recording an image of its field of view at this closest approach position, the distance between indicator ring and camera being essentially equal to the distance between the indicator stripe and the camera at this closest approach position, and an image processor and tip-tower clearance calculator unit receiving the digitally recorded image and calculating a physical separation distance between the indicator stripe and the indicator ring using the digitally recorded image information, the physical separation distance being indicative of the blade tip-tower clearance.

A system and method are provided for controlling a wind turbine in response to a blade liberation event. Accordingly, estimated response signatures for the wind turbine are determined. Sensor data indicative of at least two actual response signatures of components of the wind turbine to a rotor loading are collected. The actual response signatures are compared to the estimated response signatures. The two or more actual response signatures meeting or exceeding the estimated response signatures is indicative of a blade liberation event. In response to detecting the blade liberation event, a rapid shutdown control logic is initiated to decelerate the rotor at a rate which exceeds a nominal deceleration rate of the rotor.

A method for operating a wind turbine wherein a parameter for a wind hitting the wind turbine is determined from present values for the generator speed and/or the wind speed at each point in time (t). A temporal change variable is formed for the parameter at each point in time (t). For the temporal change variables, which occurred in a past time interval, the third and/or fourth statistical moment is calculated for a distribution of the temporal change values in the time interval. If at least one of the statistical moments exceeds a predetermined value, then a detection signal is set for an extreme gust, which triggers one or both of the steps: increasing a setpoint value for the blade pitch angle starting from an actual value thereof, and reducing a setpoint value for the generator speed starting from an actual value thereof.

A method is disclosed for controlling a wind turbine generator to provide power above a rated level. The wind turbine includes one or more electrical components that conduct current from the internal generator to supply the external grid. The control method calculates the maximum current that the electrical components can carry at the ambient temperature. The calculated current is combined with a measurement of the voltage and an estimate of reactive power in the system to give a maximum power at which the wind turbine can operate without the maximum allowable current being exceeded for the electrical components. The electrical components may be housed in the main electrical panel of the wind turbine.

An upwind wind turbine comprising a tower and a rotor is described. The wind turbine additionally includes a pressure-sensing device supported by the tower at a location within the wake of the rotor. The pressure-sensing device is configured to sense air pressure and provide a signal indicative of the sensed air pressure to a wind turbine controller for use in controlling the rotor of the wind turbine.

A method of operating a wind turbine power generating apparatus includes a step of obtaining a wind direction of a wind; a step of obtaining at least one of a wind velocity of the wind or an index of turbulence degree of the wind velocity; and a step of selecting an operation mode of the wind turbine power generating apparatus from among a plurality of operation modes including a normal operation mode and at least one load-suppressing operation mode in which a load applied to a wind turbine blade is smaller than in the normal operation mode, on the basis of whether the at least one of the wind velocity or the index of turbulence degree is at least a threshold. The threshold of the at least one of the wind velocity or the index of turbulence degree is variable in accordance with the wind direction.

A method of determining a blade clearance during operation of a wind turbine is provided, the blade clearance corresponding to a distance between a rotor blade and a tower of the wind turbine. The method includes (a) detecting a rotor blade velocity, (b) emitting a first signal from an observer location, the first signal having a first frequency, (c) receiving a second signal at the observer location, the second signal being reflected from the rotor blade when the first signal impinges on the rotor blade, (d) determining a Doppler shift of the second signal relative to the first signal, and (e) determining the blade clearance based on the first frequency, the Doppler shift, the observer location, and the rotor blade velocity, wherein the step of determining the blade clearance utilizes a mathematical model. A corre-sponding system and a wind turbine comprising such a system are also provided.

A control system and control method of a wind farm allows taking into account dynamic variations in the possibilities of reactive power generation of each wind turbine with respect to maximum reactive power generation capacities. The system is configured to receive from at least one first wind turbine of the wind turbines of the wind farm a maximum reactive power limit desired lower than a minimum reactive power capacity required. The system is configured to calculate the individual reactive power setpoints for each of the at least two wind turbines of the wind farm such that the individual reactive power setpoint for the at least one first wind turbine of the wind farm does not exceed the maximum reactive power limit desired.