Abstract: A wind turbine system comprising: a wind turbine; and a monitoring system, wherein the wind turbine comprises: a tower; an arm extending from the tower, a rotor-nacelle assembly (RNA) carried by the arm; and a Global Navigation Satellite System (GNSS) sensor carried by the arm or the RNA. The monitoring system is configured to receive position data from the GNSS sensor and obtain a moment or force measurement on the basis of the position data.

Abstract: This application describes a method of detecting an error in a rotor angle sensing system of a wind turbine, where the wind turbine comprises a rotor including a plurality of wind turbine blades, a blade load sensor associated with a respective one of the wind turbine blades, and a rotor angle sensing system configured to output a rotor angle signal. The blade load sensor is configured to output a measured blade load signal. The method comprises generating an estimated blade load signal based on at least the rotor angle signal; comparing the estimated blade load signal with the measured blade load signal to determine a phase difference between them; and identifying an error if the phase difference between the estimated blade load signal and the measured blade load signal exceeds a predetermined threshold.

Abstract: A method of correcting a pitch angle deviation of a blade of a wind turbine is provided. First blade load measurements measured when the wind turbine was operating in a first operational mode are provided, and used to determine calibration parameters. Second blade load measurements measured when the wind turbine was operating in a second operational mode are provided, and the calibration parameters applied to determine calibrated blade load measurements. A pitch angle deviation of at least one blade of the turbine is estimated based on an identified difference between the calibrated blade load measurements, and a pitch angle is adjusted to correct for the pitch angle deviation.

Abstract: A method for determining the load on a wind turbine blade, comprising: measuring the blade load by way of a wind turbine blade load sensor; estimating the temperature of the blade; and determining, based on the estimated temperature and the measured load, a temperature-corrected value for the load on the wind turbine blade. The invention also relates to a sensor system for a wind turbine blade, the system comprising a load sensor; a processing unit interfaced with the load sensor and configured to provide a temperature-corrected load parameter as an output, wherein the processing unit includes: a temperature estimation module that determines an estimated temperature of the blade in the vicinity of the load sensor based on at least one wind turbine parameter; and a load compensation module that determines the temperature-corrected load parameter based on the estimated temperature and the measurement of the load sensor.

Abstract: This application describes a method of detecting an error in a rotor angle sensing system of a wind turbine, where the wind turbine comprises a rotor including a plurality of wind turbine blades, a blade load sensor associated with a respective one of the wind turbine blades, and a rotor angle sensing system configured to output a rotor angle signal. The blade load sensor is configured to output a measured blade load signal. The method comprises generating an estimated blade load signal based on at least the rotor angle signal; comparing the estimated blade load signal with the measured blade load signal to determine a phase difference between them; and identifying an error if the phase difference between the estimated blade load signal and the measured blade load signal exceeds a predetermined threshold.

Abstract: A method of calibrating load sensors of a wind turbine, and a wind turbine for such load sensor calibration, are disclosed. The wind turbine comprises a rotor, a plurality of rotor blades, and a plurality of load sensors associated with the rotor blades. While the rotor is rotating, at least one of the rotor blades is moved from a first calibration position to a second calibration position, and load values from the load sensors are measured. The number of rotor blades being moved is at least one fewer than the number of the plurality of rotor blades. The rotation of the rotor may be during idling of the wind turbine. The movement of the blade(s) may be to change the pitch angle of the blade(s). At least one of the rotor blades not being moved to a calibration position may also be moved, for example to control the rotational speed of the rotor.

Abstract: A sensor system for a wind turbine, comprising: a blade load sensor; a blade temperature sensor configured to provide a temperature measurement of an associated blade; a load calculation module configured to output a temperature-corrected blade load value; and a processing unit interfaced with the temperature sensor. The processing unit includes a temperature estimator configured to determine an estimated temperature of the wind turbine blade based on at least one wind turbine parameter; and a comparator configured to generate a fault signal based on a comparison between the blade temperature measurement and the estimated blade temperature. The invention also resides in a corresponding method.

Abstract: A sensor system for a wind turbine blade, the system comprising: a blade load sensor providing a load measurement; a processing unit interfaced with the blade load sensor and configured to provide a corrected load parameter as an output. The processing unit includes: an axial force estimation module that determines an estimated axial force on the wind turbine blade in a direction along the length of the blade; and a load calculation module that 10 determines the corrected load parameter based on the estimated axial force and the load measurement of the blade load sensor.

Abstract: A method of measuring load on a wind turbine, and a wind turbine for such load measuring, are disclosed. The wind turbine comprises at least one rotor blade and at least one load sensor associated with the rotor blade. At least one load sensor is located at a position on the rotor blade remote from both a flap bending moment axis and an edge bending moment axis of the rotor blade. At the position, a flap bending moment component and an edge bending moment component of the load on the rotor blade are measurable. A load value is measured from the load sensor, and the measured load value is used to determine a flap bending moment component of the load and an edge bending moment component of the load, and optionally or additionally an axial force component of the load.

Abstract: A method of determining torsional deformation in a drivetrain e.g. of a wind turbine. To provide a reliable and simple deformation assessment, the method comprises the step of generating a first signal representing first rotational speed of a low speed shaft, generating a second signal representing the second rotational speed of a high speed shaft, and determining torsional deformation based on changes in the ratio between the first and second signals.

Abstract: A method of measuring load on a wind turbine, and a wind turbine for such load measuring, are disclosed. The wind turbine comprises at least one rotor blade and at least one load sensor associated with the rotor blade. At least one load sensor is located at a position on the rotor blade remote from both a flap bending moment axis and an edge bending moment axis of the rotor blade. At the position, a flap bending moment component and an edge bending moment component of the load on the rotor blade are measurable. A load value is measured from the load sensor, and the measured load value is used to determine a flap bending moment component of the load and an edge bending moment component of the load, and optionally or additionally an axial force component of the load.

Abstract: A sensor system for a wind turbine blade, the system comprising: a blade load sensor providing a load measurement; a processing unit interfaced with the blade load sensor and configured to provide a corrected load parameter as an output. The processing unit includes: an axial force estimation module that determines an estimated axial force on the wind turbine blade in a direction along the length of the blade; and a load calculation module that 10 determines the corrected load parameter based on the estimated axial force and the load measurement of the blade load sensor.

Abstract: A sensor system for a wind turbine, comprising: a blade load sensor; a blade temperature sensor configured to provide a temperature measurement of an associated blade; a load calculation module configured to output a temperature-corrected blade load value; and a processing unit interfaced with the temperature sensor. The processing unit includes a temperature estimator configured to determine an estimated temperature of the wind turbine blade based on at least one wind turbine parameter; and a comparator configured to generate a fault signal based on a comparison between the blade temperature measurement and the estimated blade temperature. The invention also resides in a corresponding method.

Abstract: A method of determining torsional deformation in a drivetrain e.g. of a wind turbine. To provide a reliable and simple deformation assessment, the method comprises the step of generating a first signal representing first rotational speed of a low speed shaft, generating a second signal representing the second rotational speed of a high speed shaft, and determining torsional deformation based on changes in the ratio between the first and second signals.

Abstract: A method for determining the load on a wind turbine blade, comprising: measuring the blade load by way of a wind turbine blade load sensor; estimating the temperature of the blade; and determining, based on the estimated temperature and the measured load, a temperature-corrected value for the load on the wind turbine blade. The invention also relates to a sensor system for a wind turbine blade, the system comprising a load sensor; a processing unit interfaced with the load sensor and configured to provide a temperature-corrected load parameter as an output, wherein the processing unit includes: a temperature estimation module that determines an estimated temperature of the blade in the vicinity of the load sensor based on at least one wind turbine parameter; and a load compensation module that determines the temperature-corrected load parameter based on the estimated temperature and the measurement of the load sensor.

Abstract: A method of calibrating load sensors of a wind turbine, and a wind turbine for such load sensor calibration, are disclosed. The wind turbine comprises a rotor, a plurality of rotor blades, and a plurality of load sensors associated with the rotor blades. While the rotor is rotating, at least one of the rotor blades is moved from a first calibration position to a second calibration position, and load values from the load sensors are measured. The number of rotor blades being moved is at least one fewer than the number of the plurality of rotor blades. The rotation of the rotor may be during idling of the wind turbine. The movement of the blade(s) may be to change the pitch angle of the blade(s). At least one of the rotor blades not being moved to a calibration position may also be moved, for example to control the rotational speed of the rotor.