Abstract: The invention relates to a method of determining a tip-to-tower clearance of a wind turbine, the wind turbine comprising a wind turbine tower, where a distance sensor unit is arranged on at least one wind turbine blade of the wind turbine and comprises at least a transmitter and a receiver, wherein the method comprises the steps of: transmitting a signal from the distance sensor unit toward the wind turbine tower, measuring a signal reflected from the wind turbine tower, determining a distance between the wind turbine tower and the at least one wind turbine blade based on the transmitted signal and the reflected signal, wherein the method further comprises the step of correcting the measured distance based on at least one of an actual pitch angle and a deflection angle of the at least one wind turbine blade at the location of the distance sensor unit.

Abstract: The invention relates to a method of condition monitoring of a wind turbine. Measurement data and operating condition parameters are captured. A subset of the operating condition parameters is selected. A set of n characterizing moments is calculated based on the subset of operating condition parameters. A finite n-dimensional space each representing possible values for one of the characterising moments is provided. The n-dimensional space is sub-divided into a number of bins each representing a n-dimensional interval defined by n one-dimensional intervals. Each one- dimensional intervals represents an interval in one of the n dimensions. Each bin defines an acceptable range for the set of n characterizing moments. The set of the characterising moments is determined if it belongs to one of the bins. The set of the characterising moments and measurement data are accepted if the set of the characterising moments belongs to one of the bins.

Abstract: In one aspect, an alarm mask for condition monitoring in a wind turbine is automatically generated. A reference data selecting definition is selected from a control definition repository in the wind turbine. The reference data selecting definition specifies a time interval of recorded reference data. Reference data is selected from a sensor located in the wind turbine recorded during the time interval. A reference value is calculated based on the reference data. A first and a second alarm mask factor are selected from the control definition repository. A first alarm mask is calculated based on multiplying the first alarm mask factor and the reference value. A second alarm mask is calculated based on multiplying the second alarm mask factor by the reference value.

Abstract: Method and apparatus for vibration-based automatic condition monitoring of a wind turbine, comprising the steps of: determining a set of vibration measurement values of the wind turbine; calculating a frequency spectrum of the set of vibration measurement values; calculating a cepstrum of the frequency spectrum; selecting at least one quefrency in the cepstrum, and detecting an alarm condition based upon an amplitude of the cepstrum at the selected quefrency, and a wind turbine therefor.

Abstract: The invention relates to a method of condition monitoring of a wind turbine. Measurement data and operating condition parameters are captured. A subset of the operating condition parameters is selected. A set of n characterizing moments is calculated based on the subset of operating condition parameters. A finite n-dimensional space each representing possible values for one of the characterising moments is provided. The n-dimensional space is sub-divided into a number of bins each representing a n-dimensional interval defined by n one-dimensional intervals. Each one-dimensional intervals represents an interval in one of the n dimensions. Each bin defines an acceptable range for the set of n characterizing moments. The set of the characterising moments is determined if it belongs to one of the bins. The set of the characterising moments and measurement data are accepted if the set of the characterising moments belongs to one of the bins.

Abstract: In one aspect, an alarm mask for condition monitoring in a wind turbine is automatically generated. A reference data selecting definition is selected from a control definition repository in the wind turbine. The reference data selecting definition specifies a time interval of recorded reference data. Reference data is selected from a sensor located in the wind turbine recorded during the time interval. A reference value is calculated based on the reference data. A first and a second alarm mask factor are selected from the control definition repository. A first alarm mask is calculated based on multiplying the first alarm mask factor and the reference value. A second alarm mask is calculated based on multiplying the second alarm mask factor by the reference value.

Abstract: Method and apparatus for vibration-based automatic condition monitoring of a wind turbine, comprising the steps of: determining a set of vibration measurement values of the wind turbine; calculating a frequency spectrum of the set of vibration measurement values; calculating a cepstrum of the frequency spectrum; selecting at least one quefrency in the cepstrum, and detecting an alarm condition based upon an amplitude of the cepstrum at the selected quefrency, and a wind turbine therefor.