A method of retrofitting a wind turbine having a tower and a first energy generating unit with a second energy generation unit is disclosed. The wind turbine has been operated for a first period of time at a first tower life rate and has a first tower life expectancy design value. The method includes determining the tower life of the wind turbine tower used during the first period of time; determining the remaining tower life of the wind turbine tower; replacing the first energy generating unit with the second energy generating unit; and operating the retrofitted wind turbine at a second tower life rate less than the first tower life rate so as to extend the life expectancy value of the tower beyond the first tower life expectancy design value.

A method is provided for monitoring a pitch control system for a rotor blade of a wind turbine. The method comprises a step of receiving a blade pitch signal representative of a pitch position of the rotor blade, a step of determining a pitch deviation, based on the blade pitch signal and a blade pitch reference. If the determined pitch deviation exceeds a first pitch deviation threshold, a pitch deviation variable is increased by an amount that depends on the determined pitch deviation, the first pitch deviation threshold, and a duration of a time period during which the determined pitch deviation has been exceeding the first pitch deviation threshold. An error signal is provided when the increased pitch deviation variable exceeds a pitch deviation variable threshold.

A method of determining an offset angle to the wind direction measured from a wind vane of a wind turbine includes the steps of: defining a plurality of power bins representing an interval of power which can be produced by the wind turbine, calculating an efficiency of the wind turbine for a plurality of time slots, determining a power output of the wind turbine for the plurality of time slots, comparing the efficiency of the wind turbine in two different time slots, and updating a value of the one of the power bins representing the interval of power determined for one of the compared time slots. The value of the power bin is updated with the result of the highest efficiency or a value derived from the highest efficiency multiplied with a constant.

A system and method are provided for controlling a wind turbine. Accordingly, a controller of the wind turbine detects a loss of traction of the slip coupling based on a difference between data indicative of a rotor operating parameter and data indicative of a generator operating parameter. The controller then determines an angle of slip corresponding to the loss of traction as a function of the difference. Based, at least partially on the angle of slip, a degradation value for the slip coupling is determined. A control action is implemented based on the degradation value.

According to an example aspect of the present invention, there is provided a sensor comprising at least one strut configured to be coupled to a surface of an object at a first end of the strut, a structure connected to a second end of the at least one strut, wherein the structure is V-shaped, U-shaped, curved or arched and configured to be coupled to the surface at both ends, a plurality of cavities positioned along the structure on both sides of the at least one strut, and a plurality of fibre-optic pressure transducers, wherein a single fibre-optic pressure transducer is arranged within each of the cavities, and wherein the sensor is configured such that at least some of the fibre-optic pressure transducers are arranged at different distances from the surface of the object.

An automated system for mitigating risk from a wind turbine includes a plurality of optical imaging sensors. A controller receives and analyzes images from the optical imaging sensors to automatically send a signal to curtail operation of the wind turbine to a predetermined risk mitigating level when the controller determines from images received from the optical imaging sensors that an airborne animal is at risk from the wind turbine.

A self-inspection method for a hydraulic control turning system of a generator rotor includes: establishing a length dimension relationship table among a plurality of hydraulic cylinders of the hydraulic control turning system; selecting a reference hydraulic cylinder, and acquiring a reference length dimension when the reference hydraulic cylinder is located at a target working position, the target working position is a position at which a turning pin corresponding to the reference hydraulic cylinder is inserted into an adapted hole; and performing a function inspection of a motion execution module in sequence by the plurality of the hydraulic cylinders, based on the reference length dimension and the length dimension relationship table.

A system and method are provided for controlling a wind turbine. Accordingly, a controller of the wind turbine detects a transient grid event and generates a torque command via a drive-train-damper control module. The torque command is configured to establish a default damping level of a torsional vibration resulting from the transient grid event. The controller also determines at least one oscillation parameter relating to the torsional vibration and determines a target generator torque level based thereon. The target generator torque level corresponds to an increased level of damping the torsional vibration relative to the default damping level.

Disclosed is a method of condition monitoring a WTG (Wind Turbine Generator) comprising acts of collecting and storage of at least the following data sets together with their time stamps. Collection of generator power production measurements. Collection of mechanical status measurements. Collection of generator torque measurements. Collection of nacelle direction measurements. Collection of meteorological conditions measurements. The method compromises a further act of synchronizing the data sets. The invention also relates to a system for condition monitoring a WTG. The invention further relates to a system for visually inspecting a WTG.

Disclosed is a method of condition monitoring a WTG (Wind Turbine Generator) comprising acts of collecting and storage of at least the following data sets together with their time stamps. Collection of generator power production measurements. Collection of mechanical status measurements. Collection of generator torque measurements. Collection of nacelle direction measurements. Collection of meteorological conditions measurements. The method compromises a further act of synchronizing the data sets. The invention also relates to a system for condition monitoring a WTG. The invention further relates to a system for visually inspecting a WTG.