A method for reducing noise of a wind turbine includes monitoring, via one or more sensors, a wind speed at the wind turbine. The method also includes determining, via a turbine controller, a nominal wind direction for producing rated power of the wind turbine. Further, the method includes determining a pitch angle of at least one rotor blade of the wind turbine. As such, the method includes determining a yaw offset for a nacelle of the wind turbine based on the wind speed and/or the pitch angle. Thus, the method further includes changing a yaw angle of the nacelle by the yaw offset when the wind speed exceeds a predetermined threshold so as to reduce noise of the wind turbine.

Methods for calculating a maximum safe over-rated power demand for a wind turbine operating in non-standard conditions include the steps of determining a value indicative of a risk of exceeding an ultimate design load during operation in a standard operating condition, and establishing a maximum over-rated power demand corresponding to a maximum power that the turbine may produce under the non-standard operating condition without incurring an increased risk of exceeding the ultimate design load, with respect to operation in the standard condition. A method of over-rating a wind turbine, a wind turbine controller, a wind turbine and a wind power plant are also claimed.

The present disclosure relates to a method for assessing a wind power installation, wherein a comparison is made between a test wind power installation and a comparison wind power installation for assessment purposes, comprising the steps of: synchronously operating the test wind power installation and the comparison wind power installation in an adjustment interval in an adjustment mode, in which the test wind power installation and the comparison wind power installation have matching operating settings, synchronously recording performance data relating to both wind power installations in each case in the adjustment interval in the adjustment mode, modifying the test wind power installation and/or the comparison wind power installation in a modification step such that the test wind power installation and the comparison wind power installation differ from one another, synchronously operating the test wind power installation and the comparison wind power installation, which differ from one another, at least in a comparison interval in a comparison mode, synchronously recording performance data in the comparison mode, and evaluating the performance data recorded in the adjustment mode and comparison mode in an evaluation step.

A system includes a wind turbine a wind and a first control device for controlling the wind turbine. The first control device is configured to acquire a yaw misalignment of the wind turbine, which yaw misalignment is a difference between the actual yaw angle and a wind direction at the wind turbine; and to determine at least one of a target pitch angle of the blade and a target torque of the generator based on the yaw misalignment to optimize a power output from the wind turbine. Further, a wind farm includes the system and a method of controlling a wind turbine.

The invention relates to a method for controlling a yaw offset of a plurality of wind turbines. The method uses a decision function which generates an activation parameter for determining if the yaw offset control of a specific wind turbine should be enabled or disabled. The decision function depends on two or more variables comprising a wind direction variable indicative of the wind direction of the specific wind turbine, and a wind variation variable defining at least a wind variation range where yaw offset control is disabled or enabled. Based on the decision function it is determined if a yaw offset should be added to the current yaw setting of the specific wind turbine.