Abstract: Systems, methods, and computer program products for determining an inclination of a wind turbine tower based on acceleration measurements by an accelerometer operatively coupled to a nacelle of the wind turbine. Acceleration data is collected from the accelerometer, which is configured to sense acceleration along an accelerometer axis while the nacelle is in each of a plurality of yaw positions. The nacelle is rotated in steps to each yaw position and stopped for a period of time. While the nacelle is stopped, acceleration data is collected, and a static level of acceleration determined along the accelerometer axis due to gravity. Once acceleration data has been collected at each of the positions, the minimum and maximum acceleration levels are identified. The inclination of the tower is then determined based on the minimum and maximum acceleration levels.

Abstract: An aspect of the invention relates to a method of reinforcing a tubular wind turbine structure using a radially adjustable ring stiffener. The ring stiffener comprises a pair of adjacent ring segments coupled together by a coupling means configured to permit radial adjustment of the ring stiffener by varying an intersegmental separation between adjacent ends of those ring segments. The method comprises: positioning the ring stiffener at a reinforcement position within the tubular wind turbine structure; and adjusting the intersegmental separation between the pair of adjacent ring segments to increase the radius of the ring stiffener; and thereby to engage an inner surface of the tubular wind turbine structure with a radial force that holds the ring stiffener at the reinforcement position by means of friction between the ring stiffener and the tubular wind turbine structure.

Abstract: The present invention relates to blade monitoring of a wind turbine by actively promoting blade vibrations by imposing a pitch actuation signal. A method of operating a wind turbine is disclosed where for each blade of a wind turbine, vibrations of the blade are actively promoted by imposing a pitch actuation signal to the pitch actuator, and at least one parameter relating to the blade vibration is determined.