A method for stopping the operation of a wind turbine is disclosed. The method may generally include receiving signals associated with at least one operating condition of the wind turbine, analyzing the at least one operating condition with a controller of the wind turbine, implementing a first stopping procedure in order to stop operation of the wind turbine when analysis of the at least one operating condition indicates that a pitch system failure has occurred and implementing a second stopping procedure in order to stop operation of the wind turbine when analysis of the at least one operating condition indicates that a different wind turbine stop event has occurred.

A method for controlling the operation of a wind turbine may generally include monitoring a current yaw position of a nacelle of the wind turbine, wherein the current yaw position is located within one of a plurality of yaw sectors defined for the nacelle. In addition, the method may include monitoring a wind-dependent parameter of the wind turbine and determining a variance of the wind-dependent parameter over time, wherein the variance is indicative of variations in a wind parameter associated with the wind turbine. Moreover, the method may include determining at least one curtailed operating setpoint for the wind turbine when the variance exceeds a predetermined variance threshold, wherein the curtailed operating setpoint(s) is determined based at least in part on historical wind data for the yaw sector associated with the current yaw position.

The present invention relates to control of a wind turbine where nacelle vibration is reduced by use of blade pitching. The nacelle vibrations are reduced based on a position signal of the nacelle. A pitch signal is determined based on the position signal and applied to the pitch-adjustable rotor blades in order to reduce nacelle vibration.

Provided are a method and an apparatus for controlling a pitch of a wind turbine under an extreme turbulence wind condition. The method includes: obtaining a first pitch parameter for a current time; obtaining a historical second pitch parameter in a predetermined time period before the current time; determining an updated threshold based on the obtained historical second pitch parameter; comparing the first pitch parameter for the current time with the determined updated threshold; and updating the first pitch parameter for the current time based on a result of the comparison.

A method for protecting a wind turbine from overloading during operation caused by a fault includes receiving, via a controller, a plurality of pitch signals from a plurality of pitch control mechanisms of a pitch system of the wind turbine, the pitch system configured to rotate a plurality of rotor blades mounted to a rotatable hub of a rotor of the wind turbine about respective pitch axes. Further, the method includes determining a collective pitch rate of the pitch system as a function of the plurality of pitch signals. The method also includes defining a minimum pitch rate threshold that varies with a speed parameter of the wind turbine. Moreover, the method includes receiving a first speed parameter of the wind turbine. In addition, the method includes comparing the collective pitch rate to the minimum pitch rate threshold for the first speed parameter. Thus, the method includes controlling the wind turbine based on the comparison.

A method for detecting an accretion of ice on a rotor blade of a rotor of a wind turbine is provided. The can be operated at a variable rotational speed. The method includes recording a wind speed of a wind acting upon the rotor, recording an operating variable that is dependent on the wind speed and comparing the recorded operating variable or the recorded wind speed with a reference variable of a characteristic wind-speed-dependent operating-variable curve of the wind turbine. The characteristic operating-variable curve indicates an operating variable assumed to be optimal in dependence on the wind speed. The method includes detecting an accretion of ice on the rotor blade if the recorded operating variable or the recorded wind speed, deviates from the reference variable by at least a predetermined minimum deviation specified in dependence on the wind speed.

A method for controlling a wind power installation, wherein the wind power installation has a rotor with a plurality of rotor blades, the rotor blades are adjustable in their blade angle, each rotor blade is activatable individually, for the individual activation, in each case a total adjustment rate R.sub.of which indicates an intended speed of change of the respective blade angle is predetermined, a collective blade angle identical for all of the rotor blades is provided, a collective adjustment rate identical for all of the rotor blades describes an intended speed of change of the collective blade angle, an individual offset angle which indicates a value by which the blade angle is intended to deviate from the collective blade angle is predetermined for each rotor blade, an individual feed forward control adjustment rate which indicates an adjustment rate which is provided for reaching the offset angle is determined for each rotor blade from the individual offset angle, an individual offset deviation is determined for each rotor blade depending on a comparison of the individual offset angle and a detected blade angle of the rotor blade, and the total adjustment rate of each rotor blade is determined depending on the collective blade angle and/or the collective adjustment rate, the individual feed forward control adjustment rate, and the individual offset deviation.

A method for setting a pitch angle of a rotor blade for a rotor of a wind turbine, a control device for setting a pitch angle of a rotor blade for a rotor of a wind turbine, and a wind turbine. In particular, a method for setting a pitch angle of a rotor blade for a rotor of a wind turbine, in particular for avoiding suction-side flow separation, wherein the rotor blade is movable rotationally about a rotor blade longitudinal axis for setting the pitch angle by means of a pitch drive, comprising the steps: determining an aerodynamic power of the rotor, establishing a nominal pitch angle as a function of the aerodynamic power, and setting the pitch angle to the established nominal pitch angle.

A method for protecting a wind turbine from overloading during operation caused by a fault includes receiving, via a controller, a plurality of pitch signals from a plurality of pitch control mechanisms of a pitch system of the wind turbine, the pitch system configured to rotate a plurality of rotor blades mounted to a rotatable hub of a rotor of the wind turbine about respective pitch axes. Further, the method includes determining a collective pitch rate of the pitch system as a function of the plurality of pitch signals. The method also includes defining a minimum pitch rate threshold that varies with a speed parameter of the wind turbine. Moreover, the method includes receiving a first speed parameter of the wind turbine. In addition, the method includes comparing the collective pitch rate to the minimum pitch rate threshold for the first speed parameter. Thus, the method includes controlling the wind turbine based on the comparison.

Provided are a wind turbine, and a control method, a controller and a control system for the same. The control method includes: monitoring wind resource data at the location of a wind turbine and operation data of the wind turbine; identifying a complicated wind condition based on the wind resource data and the operation data; determining an accumulative proportion of time periods in which the complicated wind condition occurs within a first predetermined time period; and controlling the wind turbine to perform a protection operation, in response to the accumulative proportion of the time periods exceeding a first preset threshold.