Abstract: A method for the determination of the deflection of a wind turbine blade is provided. A distance between at least one root location towards a root end of the wind turbine blade and at least one tip location towards a tip end of the wind turbine blade is measured. A blade deflection profile is then calculated based on the measured distance between the root and tip locations and a known modal profile of the wind turbine blade.

Abstract: A wind turbine blade comprising a system for monitoring the deflection of a wind turbine blade is described. The system comprises a wireless range-measurement system, having at least one wireless communication device located towards the root end of the blade and at least one wireless communication device located towards the tip end of the blade, the communication devices comprising antennas polarized substantially perpendicular to the suction side of the blade and substantially parallel to the leading edge of the wind turbine blade.

Abstract: A system for monitoring the deflection of a wind turbine blade is described. The system comprises a wireless range-measurement system, having at least one wireless communication device located towards the root end of the blade and at least one wireless communication device located towards the tip end of the blade. The root end device is provided on a bracket projecting from the external surface of the blade, to provide a communication path between the root end and tip end devices which is less susceptible to interference from multipath effects, etc. There is further provided a method to derive tilt and yaw moments from measured deflections. A control method for such a system is also described, wherein the signal gain of the communication path may be varied based at least in part upon the deflection characteristics of the wind turbine blade.

Abstract: A wind turbine blade comprising a system for monitoring the deflection of a wind turbine blade is described. The system comprises a wireless range-measurement system, having at least one wireless communication device located towards the root end of the blade and at least one wireless communication device located towards the tip end of the blade, the communication devices comprising antennas polarized substantially perpendicular to the suction side of the blade and substantially parallel to the leading edge of the wind turbine blade.

Abstract: A system and method for the verification and calibration of wind turbine sensor systems is provided. The system comprises an optical capture device provided on a wind turbine which is arranged to record the position of at least one light source provided at the wind turbine during operation of the wind turbine. The motion of the light source relative to the optical capture device can provide an indication of relative motion of a portion of the wind turbine during operation, which can then be used as an input to a calibration and/or a verification system for a sensor system of the wind turbine.

Abstract: A method for the calculation of a wind turbine blade deflection is described. The method utilises a known blade modal profile in the calculation of the blade deflection, such that the a priori knowledge of the blade excitation modes can be used with a simple distance measurement to determine the blade deflection shape. The calculated blade deflection can then be used as an input to control wind turbine operation, e.g. where it is likely that the deflected blade might result in a tower strike.

Abstract: A system and method for the verification and calibration of wind turbine sensor systems is provided. The system comprises an optical capture device provided on a wind turbine which is arranged to record the position of at least one light source provided at the wind turbine during operation of the wind turbine. The motion of the light source relative to the optical capture device can provide an indication of relative motion of a portion of the wind turbine during operation, which can then be used as an input to a calibration and/or a verification system for a sensor system of the wind turbine.

Abstract: A system for monitoring the deflection of a wind turbine blade is described. The system comprises a wireless range-measurement system, having at least one wireless communication device located towards the root end of the blade and at least one wireless communication device located towards the tip end of the blade. The root end device is provided on a bracket projecting from the external surface of the blade, to provide a communication path between the root end and tip end devices which is less susceptible to interference from multipath effects, etc. There is further provided a method to derive tilt and yaw moments from measured deflections. A control method for such a system is also described, wherein the signal gain of the communication path may be varied based at least in part upon the deflection characteristics of the wind turbine blade.