A wind turbine and method are provided for defining a plurality of thrust limits for the wind turbine located at a site and having a rotor with rotor blades, wherein the thrust limits define values of aerodynamic thrust on the rotor not to be exceeded in operation. The method includes providing a wind speed distribution representative for the site and defining one or more isolines of constant turbulence probability representing a turbulence parameter as a function of wind speed. The isolines correspond to quantile levels of turbulence of the wind speed distribution and the turbulence parameter is indicative of wind speed variation. The turbulence parameter is determined by continuously measuring wind speed upstream of the rotor with an active sensing system and calculating the wind speed variations from the measured wind speed. Turbulence ranges are defined with respect to the isolines and thrust limits are defined for the turbulence ranges.

Provided are a wind farm noise prediction method, apparatus and system. The method comprises: collecting, in real time, a wind speed at a site of at least one wind turbine generator system, which impacts noise at a noise detection point, in a wind farm; according to a noise acoustic power level database and a system database, respectively calculating a noise acoustic power level, at the collected wind speed, of each wind turbine generator system from among the at least one wind turbine generator system; according to a wind farm noise propagation database, respectively calculating a noise propagation loss value, at the collected wind speed, of each wind turbine generator system; and using the noise acoustic power level and the noise propagation loss value of each wind turbine generator system to calculate a total noise acoustic pressure level at the noise detection point.

Provided is a system for determining a soiling state of a wind turbine rotor blade. The system includes a pressure sensor adapted to measure a plurality of pressure values corresponding to a plurality of different heights above a trailing edge region of the wind turbine rotor blade, and a processing unit in communication with the pressure sensor and adapted to determine the soiling state of the wind turbine rotor blade by estimating an air flow velocity distribution above the trailing edge region of the wind turbine rotor blade based on the plurality of pressure values. Furthermore, a corresponding method of determining a soiling state of a wind turbine rotor blade is described.

A method for controlling a wind turbine is disclosed, the wind turbine comprising a set of wind turbine blades (1), each wind turbine blade (1) being provided with at least one air deflector (2) being movable between an activated position in which it protrudes from a surface of the wind turbine blade (1) and a de-activated position. The occurrence of an event causing a change in operational conditions is registered, and a new operating state for the wind turbine is determined, the new operating state meeting requirements of the changed operational conditions. The air deflectors (2) of the wind turbine blades (1) and pitch angles of the wind turbines blades (1) are controlled in order to reach the new operating state for the wind turbine, and in such a manner that the control of the pitch angles of the wind turbine blades (1) is performed while taking information regarding the control of the air deflectors (2) into account.

A system comprising a blade pitch system having a set of locking holes. A pitch drive assembly is coupled to the blade pitch system and configured to rotate clockwise or counterclockwise within a range of angular degrees to adjust a blade pitch angle. The system includes a pitch lock pin-and-hole system including an interface plate and at least one blade pitch lock assembly coupled to the interface plate. Each lock assembly includes a locking pin having a pin center axis parallel with a center axis of a locking hole to engage a respective one locking hole of the set to lock the blade pitch angle.

A method for controlling a wind turbine and an associated wind turbine. The wind turbine is operated according to an operating point, wherein the operating point is determined at least by a pitch angle and a tip speed ratio, wherein one of the operating points corresponds to a maximum power coefficient, wherein, in a partial load range, the wind turbine is operated at an operating point which differs from the operating point with the maximum power coefficient. The distance of the operating point from the operating point with the maximum power coefficient is set in accordance with a measured turbulence measure.

A vertical axis wind turbine includes two or more cells arranged one above the other along a vertical machine axis, wherein each of the cells includes a plurality of vertical blades which are arranged within the cell distributed on a concentric circle about the machine axis and which are connected so as to be able to move together on this circle and which are rotationally fixed with a main shaft, and wherein the blades in the cell are each individually mounted so as to be able to rotate about a vertical axis of rotation which in particular runs internally through them.

Provided are a wind farm noise prediction method, apparatus and system. The method comprises: collecting, in real time, a wind speed at a site of at least one wind turbine generator system, which impacts noise at a noise detection point, in a wind farm; according to a noise acoustic power level database and a system database, respectively calculating a noise acoustic power level, at the collected wind speed, of each wind turbine generator system from among the at least one wind turbine generator system; according to a wind farm noise propagation database, respectively calculating a noise propagation loss value, at the collected wind speed, of each wind turbine generator system; and using the noise acoustic power level and the noise propagation loss value of each wind turbine generator system to calculate a total noise acoustic pressure level at the noise detection point.

The present invention relates to wind turbines with variable rotor blades whose pitch angles are adjustable. An adjustment unit is provided for adjusting the pitch angle of the rotor blades with a pivot bearing comprising at least two coaxial bearing rings that are rotatable against each other, at least one adjustment actuator for rotating the two bearing rings, and a supply unit for supplying the adjustment actuator with energy, whereby the adjustment actuator and the supply unit are disposed on opposite sides on a plate-shaped adjustment drive carrier part which is rotatably connected with one of the bearing rings and comprises a rotatable support bearing for the support of the adjustment actuator. A least one part of the supply unit is rotatably mounted on the carrier part such that the supply unit or its rotatably mounted part and the adjustment actuator are jointly rotatably mounted and/or swivel-mounted on the carrier part.

The invention relates to control of a wind turbine comprising a plurality of multi-axial accelerometers mounted at different positions in the nacelle and/or in a top portion of the tower. The position and orientation of each accelerometer as mounted is obtained, accelerations in at least two different directions by each accelerometer are measured during operation of the wind turbine. From a number of predetermined mode shapes for the movement of the wind turbine is then determined an absolute position of at least one of the accelerometers during operation of the wind turbine based on the measured accelerations, the mount position and orientation of each accelerometer and the pre-determined mode shapes. Hereby a more precise absolute position during operation is obtained which can be used in the controlling of the turbine.