The present disclosure provides a control method and device for avoiding run-away, and a wind turbine. The method may include: determining whether a brake system of the wind turbine has failed; if the brake system has failed, calculating an initial crosswind position based on a current wind direction angle, and enabling a yaw system of the wind turbine to perform a crosswind operation based on the initial crosswind position; performing a long-period and short-period filter processing on wind direction data acquired during a crosswind process to obtain an average and instantaneous wind direction angle respectively; determining whether a wind direction has a sudden change based on the average and instantaneous wind direction angle; and if the wind direction has a sudden change, calculating a new crosswind position based on the average wind direction angle, and enabling the yaw system to perform a crosswind operation based on the new crosswind position.

Provided is a method for operating a wind turbine, an associated wind turbine and a wind park. The method comprises a) providing an indicator for the occurrence of a flow separation on a pressure side of a rotor blade of a rotor of the wind turbine, and b) changing an operational management of the wind turbine using the indicator, wherein the indicator comprises a pitch angle of the rotor blade. By using the pitch angle as an indicator, a flow separation on the pressure side of the rotor blade can be effectively prevented.

Techniques for controlling loading on a wind turbine blade in the flap-wise direction. A system model has a description of flap loading on the blade and is used to predict flap loading on the blade over a prediction horizon using the system model. A dynamic flap loading limit is determined based on predicted flap loading and a measured flap loading, and a constraint is defined to limit flap loading on the blade based on the dynamic flap loading limit. The predicted flap loading is used in a cost or performance function, and the cost function is optimized subject to the constraint to determine pitch for the blade to control flap loading on the blade. Advantageously, the dynamic limit varies based on discrepancies between predicted and measured flap loading to allow for adaptive back-off from extreme loads prior to such loads building up or being exceeded.

A method for determining an incident flow at a rotor blade of a wind power installation is provided. The method includes recording at least part of a pressure spectrum of pressure, in particular wall pressure, at the rotor blade at at least one measurement position. The method includes determining at least two characteristic values from the pressure spectrum, determining an indicator value from a relationship between the at least two characteristic values and assessing whether a critical incident flow is present depending on the indicator value.

A method for operating a wind turbine includes determining at least one wind condition of the wind turbine for a plurality of time intervals. The method also includes determining a status of the wind turbine at the beginning of each of the plurality of time intervals. Further, the method includes determining at least one vibration parameter of the wind turbine for one or more preceding time intervals of the plurality of time intervals. Moreover, the method includes predicting whether a trip event is imminent based on the at least one wind condition, the status of the wind turbine at the beginning of each of the plurality of time intervals, and the vibration parameter. Thus, the method further includes implementing a control action for the wind turbine so as to prevent the trip event.

A method for operating a wind turbine to avoid stall during derating thereof includes providing an initial pitch setting for one or more rotor blades of the wind turbine. Further, the method includes operating the wind turbine based on a rated power curve with the one or more rotor blades fixed at the initial pitch setting. Further, the method includes identifying at least one condition of the wind turbine that is indicative of stall. The method also includes derating the wind turbine. Further, the method includes modifying the initial pitch setting to an updated pitch setting when the at least one condition is identified.

A sensor device for measuring flow-separation on an aerodynamic element, including a number of compliant elements with aerodynamic and/or structural properties designed to allow flow-induced vibrational motion in an air current and a sensor-element designed to measure vibrations of the number of compliant elements is provided. Further provided is an aerodynamic element, e.g. a wind turbine blade or an airfoil, with such sensor device, a method for controlling the angle of attack of an aerodynamic element, a controlling device and a wind turbine.

A method for protecting a wind turbine from an extreme change in wind direction includes receiving a wind direction and/or a wind speed at the wind turbine. When a change in the wind direction or the wind speed exceeds a predetermined threshold, the method includes determining a margin to stall and/or zero lift of the at least one rotor blade of the wind turbine as a function of an angle of attack or change in the angle of attack at a blade span location of at least one rotor blade of the wind turbine. The method also includes implementing a corrective action for the wind turbine (without shutting down the wind turbine) when the margin to stall and/or zero lift exceeds a predetermined value so as to avoid stall and/or negative lift on the at least one rotor blade during operation of the wind turbine.

Methods of measuring a stall condition of a rotor of a wind turbine are disclosed. In one aspect a stall parameter is obtained on the basis of the power parameter and a thrust parameter; and the stall parameter compared with a threshold to determine a stall condition of the rotor.

Techniques for controlling loading on a wind turbine blade in the flap-wise direction. A system model has a description of flap loading on the blade and is used to predict flap loading on the blade over a prediction horizon using the system model. A dynamic flap loading limit is determined based on predicted flap loading and a measured flap loading, and a constraint is defined to limit flap loading on the blade based on the dynamic flap loading limit. The predicted flap loading is used in a cost or performance function, and the cost function is optimized subject to the constraint to determine pitch for the blade to control flap loading on the blade. Advantageously, the dynamic limit varies based on discrepancies between predicted and measured flap loading to allow for adaptive back-off from extreme loads prior to such loads building up or being exceeded.