Abstract: A method to control a wind power installation is provided. The wind power installation includes a generator and a converter. The generator is configured to convert wind power into electrical power and to provide the electrical power from the generator to the converter. The converter is configured to adapt and to provide the electrical power to an electrical grid. The converter is operable to comply with pre-determined grid code requirements during a grid fault. An amount of electrical power, which is present in the wind power installation during the grid fault, is fed into the generator. The generator is operable to convert the respective amount of electrical power into a generator loss.

Abstract: Provided is a method for determining at least one characteristic of a boundary layer a wind turbine rotor blade, including capturing at least one movement of at least one flexible element of at least one sensor being attached to or being part of a surface of the rotor blade, determining the at least one characteristic of the boundary layer based on the at least one captured movement of the at least one flexible element. Further, a sensor device, a wind turbine and a device as well as a computer program product and a computer readable medium are suggested for performing the method.

Abstract: A method is provided for determining an orientation of a rotor plane of a wind turbine, including the following steps: determining direction information of a moving part of a wind turbine on basis of at least one signal of a positioning system received at the moving part, determining the orientation of the rotor plane on basis of the determined direction information. Further, a wind turbine and a device as well as a computer program product and a computer readable medium are suggested for performing the method.

Abstract: Provided is a method of controlling a rotational speed of a rotor of a wind turbine having a rotor with blades connected thereon, at least one blade including a blade profile changing equipment, the method including: changing the blade profile dependent on a rotational speed deviation of an actual rotational speed of the rotor or the generator rotor from a reference rotational speed.

Abstract: Provided is a method of controlling a permanent magnet generator, the method including: measuring mechanical noise of the generator; deriving two quantities indicative of an amplitude and a phase of an undesired harmonic of the measured noise; deriving, based on the quantities, a current to be injected in stator coils of the generator such as to reduce the undesired harmonic.

Abstract: Provided is a method of determining an inclination angle of a wind turbine tower at which a nacelle is mounted, the method including measuring plural acceleration values of an acceleration of the nacelle in a predetermined direction relative to the nacelle for plural yawing positions of the nacelle; deriving the inclination angle based on the plural acceleration values.

Abstract: Provided is a method for damping a side-side oscillation of a tower of a wind turbine having a generator connected to a converter, the method including: measuring an acceleration value of the tower; determining, based on the acceleration value, at least one frequency value of at least one tower oscillation mode, including a second tower oscillation mode; controlling the converter of the wind turbine based at least on the acceleration value and the frequency value.

Abstract: A method for computer-assisted determination of usage of electrical energy produced by a power generation plant such as a renewable power generation plant is provided. The method uses a plurality of neural networks having a different structure or being learned differently for calculating future energy amounts produced by a power generation plant. To do so, the energy outputs of the power generation plant forecasted by the plurality of the neural networks are used to build histograms. Based on the histograms, energy amounts for different confidence levels describing the likelihood of the availability of the energy amount are determined, and different uses are assigned to different energy amounts. Energy amounts having a higher likelihood of availability in the future are sold at higher prices than other energy amounts.

Abstract: A method for estimating grid properties of a power grid coupled to a generator at a point of common coupling is provided. First, a voltage VPCC at the point of common coupling is measured. Second, a current IPCC at the point of common coupling is measured. Third, the grid properties are estimated by a grid model using as input parameters the measured voltage VPCC at the point of common coupling, the measured current IPCC at the point of common coupling and the determined phase angle. Advantageously, the absolute phases of the voltage and the current at the point of common coupling are not necessary, which makes the present method less prone to errors due to measurement noise. Further, a device and a computer program product are provided.

Abstract: A method is proposed for operating at least one wind turbine of a wind farm including determining wind turbine individual offset information based on reactive power provided by the respective wind turbine and reactive power provided by at least one further wind turbine of the wind farm, determining wind turbine individual control information based on the wind turbine individual offset information and wind farm specific control information, operating the at least one wind turbine according to the wind turbine individual control information. Further, a controller and a device as well as a computer program product and a computer readable medium are also provided.

Abstract: A method is proposed for detecting damage to at least one rotor blade of a wind turbine, including the following steps, monitoring during rotation of the at least one rotor blade at least one internal air condition inside a blade root of the at least one rotor blade, wherein the internal air condition is affected by a centrifugal effect pumping the air inside the at least one rotor blade from a root end towards a tip end and out of at least one hole of the at least one rotor blade, detecting damage to the at least one rotor blade based on the at least one monitored internal air condition. Further, a wind turbine and a device as well as a computer program product and a computer readable medium are suggested for performing the method.

Abstract: Provided is a method of controlling a rotational speed of a rotor of a wind turbine having a rotor with blades connected thereon, at least one blade including a blade profile changing equipment, the method including: changing the blade profile dependent on a rotational speed deviation of an actual rotational speed of the rotor or the generator rotor from a reference rotational speed.

Abstract: A method for adjusting a power parameter of a wind turbine is disclosed. The method includes determining a load parameter indicative of a mechanical load of the wind turbine; estimating a turbulence of a wind speed based on the determined load parameter; and adjusting the power parameter relating to a power of the wind turbine based on the estimated turbulence. A system for adjusting a power parameter of a wind turbine is also described.

Abstract: A method for detecting a rotor blade pitch angle adjustment fault of a rotor blade of a wind turbine is provided, the method includes measuring a rotor blade pitch angle speed; predicting, based on an actual rotor speed, a rotor blade pitch angle speed; indicating a fault, if a first criterion is satisfied, wherein the first criterion is satisfied, if deviation between the measured rotor blade pitch angle speed and the predicted rotor blade pitch angle speed exceeds a speed threshold.

Abstract: A method is proposed for operating at least one wind turbine of a wind farm including determining wind turbine individual offset information based on reactive power provided by the respective wind turbine and reactive power provided by at least one further wind turbine of the wind farm, determining wind turbine individual control information based on the wind turbine individual offset information and wind farm specific control information, operating the at least one wind turbine according to the wind turbine individual control information. Further, a controller and a device as well as a computer program product and a computer readable medium are also provided.

Abstract: A method is provided for calibrating a yaw system of a wind turbine, including the following steps: determining a true sun position in relation to the position of the wind turbine, calibrating the yaw system based on the true sun position and based on turbine specific information. Further, a wind turbine and a device as well as a computer program product and a computer readable medium are suggested for performing said method.

Abstract: A method to control a wind power installation is provided. The wind power installation includes a generator and a converter. The generator is configured to convert wind power into electrical power and to provide the electrical power from the generator to the converter. The converter is configured to adapt and to provide the electrical power to an electrical grid. The converter is operable to comply with pre-determined grid code requirements during a grid fault. An amount of electrical power, which is present in the wind power installation during the grid fault, is fed into the generator. The generator is operable to convert the respective amount of electrical power into a generator loss.

Abstract: A method of operating a wind park having a plurality of wind turbines is provided. The method includes determining a grid condition indicator indicative of the condition of a grid into which the wind park feeds; determining a first maximum power value of the wind park on the basis of the grid condition indicator; determining an operating margin on the basis of the grid condition indicator, for a grid condition indicator indicative of a weak grid; determining a second maximum power value on the basis of the operating margin; and curtailing the active power output of the wind park according to a maximum power value. A computer program product for carrying out the steps of such a method; an active power controller adapted for use in operating a wind turbine of a wind park; a wind turbine; and a wind park are also provided.

Abstract: A wind turbine device having in one embodiment a diesel generator to initialize a black start in case of a blackout of an electricity network is disclosed. For performing the black start, the diesel generator provides a predetermined voltage to a power output of the wind turbine device in order to imitate the electricity network in its running state. A wind park is also disclosed, the wind park having in one embodiment at least two wind turbine devices. In one embodiment a wind park controller provides the same reference value for the phase angle ? for the at least two turbines.

Abstract: An arrangement to measure deflection of a blade of a wind turbine is provided. A transmitter is arranged close to the tip end of the blade, while a receiver is arranged close to the root end of the blade. The transmitter and receiver are prepared for a wireless transfer of a monitoring signal, which is sent from the transmitter to the receiver. A monitoring system is arranged close to the root end of the blade. The monitoring system is adapted to generate the monitoring signal. The monitoring system is connected with the transmitter by a cable-bound communication line, thus the monitoring signal is transferred from the monitoring system to the transmitter. The monitoring system is connected with the receiver, thus the monitoring signal is transferred from the receiver to the monitoring system. The monitoring system is adapted to determine the deflection of the blade based on the transferred monitoring signal.