A method for operating a wind turbine is provided. The wind turbine includes a rotor adapted to rotate at an optimal speed. The method includes determining a turbulence parameter; and operating the wind turbine at a speed that is increased by a speed deviation amount as compared to the optimal speed. The speed deviation amount is dependent on the turbulence parameter. A wind turbine (100) having a controller (202) for controlling the wind turbine according to the disclosed method is also provided.

A method for controlling a power output of a power generating unit is disclosed. An accumulated power output of the power generating unit during a predefined time interval is forecasted. An actual power output of the power generating unit is measured during the predefined time interval, and an actual accumulated power output is estimated for the predefined time interval on the basis of the measured actual power output of the power generating unit. A difference between the forecasted accumulated power output and the estimated actual accumulated power output is derived. The power output of the power generating unit is boosted, in the case that the estimated actual accumulated power output is below the forecasted accumulated power output, and the difference between the forecasted accumulated power output and the estimated actual accumulated power output is larger than a predefined threshold value.

A control arrangement for a variable-speed wind turbine includes a loading analysis module configured to analyse a number of environment values to establish whether the momentary wind turbine loading is lower than a loading threshold when the rotational speed of the aerodynamic rotor has reached its rated value; and a speed boost module configured to determine a speed increment for the rotational speed of the aerodynamic rotor if the wind turbine loading is lower than the loading threshold.

Techniques are provided for control of a wind turbine where a torque limit is set based on a control signal. A current torque value of a rotor of the wind turbine is determined and compared to an upper torque limit value and the control signal is modified if the current torque value is larger than the upper torque limit value. The upper torque limit value is based on a lower envelope signal which tracks the current torque value if the current torque value is lower than or equal to the previous lower envelope value and is set as a rising signal if the current torque value is higher than the previous lower envelope value. The upper torque limit is set to be a first amount higher than the lower envelope signal.