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 for operating a power generation system coupled to a power grid during a grid unbalance event, a method for determining an injection current to be supplied into a power grid by a power generation system, and a method for addressing an asymmetric grid fault in a power grid connected to a power generation system are provided. The methods may be carried out based on a reactive or an active power/current priority.

Abstract: A power generation system, wind turbine, and method of pulse width modulation (PWM) for power converters are disclosed. The method generally includes generating a substantially random distribution of timing values, applying a filter to the random distribution to produce a modified random distribution, and delivering PWM timing signals based on the modified random distribution to the power converters.

Abstract: A wind turbine tower configured to support a wind turbine nacelle and a rotor, and with a tower wall of an inner surface and an outer surface. The tower is tethered by a number of cables, each cable extending between a first end anchored to an anchoring element and an opposite, second end attached to the tower at an attachment element. Two cables extending from two different anchoring elements are attached to the tower such that longitudinal projection lines from the second ends of the two cables converge at a convergence point, which lies at a location at a certain height and inside the tower wall thickness. Alternatively, the convergence point lies inside the tower within a distance of three wall thicknesses from the wall inner surface as measured at the height and in a direction perpendicular to the central longitudinal axis of the tower.

Abstract: The present invention relates to a method of manufacturing a wind turbine blade or a part of a wind turbine blade. The method comprises arranging at least one of layer of uncured resin pre-impregnated fibres, called prepregs, and at least one layer of cured fibre reinforced resin in an at least partly overlaying relationship, and curing the resin of the at least one layer comprising uncured resin. The at least one layer of cured fibre reinforced resin is assembled with at least one layer of uncured resin-preimpregnated fibres prior to being placed on a moulding surface. The method may e.g. be used to manufacture a wind turbine blade shell member or a wind turbine blade spar member. The invention further relates to a wind turbine blade shell member or a wind turbine blade spar member manufactured by such a method.

Abstract: A method, converter arrangement, and controller are disclosed for connecting an output of a converter with an electrical grid to control inrush currents into a grid filter assembly connected with the output of the converter, the electrical grid carrying an alternating current (AC) signal having one or more phases. The method includes determining a voltage of the AC signal and operating, after pre-charging a direct current (DC) link of the converter to a predetermined voltage, the converter using open-loop voltage control to produce an AC output signal that substantially matches the AC signal of the electrical grid. The open-loop voltage control is based on the determined voltage of the AC signal. The method further includes closing, after a predetermined amount of time of operating the converter using the open-loop voltage control, a switching device to thereby connect the output of the converter with the electrical grid.

Abstract: The invention presents a method for operating a horizontal axis wind turbine, the wind turbine comprising a tower and a rotor with at least one rotor blade, the rotor being connected to the tower, and being adapted to drive a generator connected to a utility grid, wherein a pitch angle of each rotor blade is adjustable, the method comprising detecting, when the wind turbine is in an idling power producing situation in relation to the utility grid, a tower oscillation, and controlling, when the wind turbine is in the idling power producing situation, the pitch angle of the at least one rotor blade so as to produce aerodynamic forces counteracting the detected tower oscillation.

Abstract: A method for controlling a wind turbine is provided. The wind turbine is a turbine of the type that is operated to perform a control function that controls the amount of power produced based upon measures of fatigue life consumption of one or more turbine components. The method comprises initialising the control function by: over-riding or bypassing (405) the control function for a predetermined period of time, such that power produced by the wind turbine is not altered based upon the determined measures of fatigue life consumption; during the predetermined period of time, operating (407) one or more fatigue lifetime usage estimation algorithms, to determine a measure of the fatigue life consumed by each of the one or more turbine components; and after the predetermined period of time has elapsed, activating (409) the control function and using, in the control function, at least one of the measures of fatigue life consumption determined during the predetermined period of time.

Abstract: A lifting arrangement (1) for lifting a wind turbine tower segment (2), the lifting arrangement (1) comprising at least two component pulley arrangements (3) connected to a flange (5) of the tower segment, and at least one hoisting pulley arrangement (4), arranged to be connected to a hoisting apparatus. A rope (8) interconnects the component pulley arrangements (3) and the hoisting pulley arrangements (4), in such a manner that each component pulley arrangement (3) is connected to two hoisting pulley arrangements (4), or to one hoisting pulley arrangement (4) and a rope end attachment point (9), via the rope (8), and each hoisting pulley arrangement (4) is connected to two component pulley arrangements (3), via the rope (8), the rope (8) being arranged movably in each pulley arrangement (3, 4). The tower segment (2) is automatically rotated from a first orientation into a second orientation during the lifting process. Load distribution among various parts of the rope (8) is ensured.

Abstract: For fixating a blade segment (1a) of a rotor blade of a wind turbine to a mould (20a), in which the blade segment is manufactured, a fixing device (10) is provided comprising a first portion (11) for selectively applying a clamping force on the fixating extension and a second portion (12) for fixating the fixing device to the mould. In the fixing device (10) one of the first and second portions comprises a cylinder portion (15a) with a threaded structure, and a threaded abutment structure (15b) encircling the cylinder portion and engaging its threaded structure. The respective other portion comprises an aperture (14) and a recess with a second abutment structure (16a) within the aperture. The aperture (14) is adapted to receive the cylinder portion (15a) such that the cylinder portion (15a) protrudes the aperture (14) along its cylinder axis, and the second abutment structure (16a) is adapted to engage and exert a force on the threaded abutment structure (15b) in a direction parallel to the cylinder axis.

Abstract: Controlling a wind turbine during a grid fault where the grid voltage drops below a nominal grid voltage. After detection of a grid fault, the total current limit for the power converter output is increased to a total maximum overload current limit. Depending on whether active or reactive current generation is prioritized, an active or reactive current reference is determined. The active current reference is determined in a way so that a reduction in active power production due to the grid voltage drop is minimized and based on the condition that the vector-sum of the active output current and the reactive output current is limited according to the total maximum overload current limit, and a maximum period of time is determined in which the power converter can be controlled based on the active/reactive current references. Afterwards the power converter is controlled based on the active and reactive current references.

Abstract: A wind turbine system comprising a plurality of wind turbine modules mounted to a support structure, wherein each of the wind turbine modules comprises a rotor including one or more variable-pitch blades, each defining a respective blade pitch angle and being controlled by a pitch control system, and a control system operable to control the blade pitch angles of the plurality of blades of the wind turbine modules. The control system is configured to identify the presence of a predetermined stop condition and, in dependence thereon, is operable to control the blade pitch angles of the respective blades to predetermined stop positions that reduce oscillation of the support structure. Aspects of the invention also relate to a method of controlling a wind turbine system, to a controller for implementing the method, and to a computer program product.

Abstract: A cabinet comprising an outer wall which encapsulates an internal space comprising electronic components, the outer wall having a rupture line forming a release wall portion which by rupturing of the rupture line in response to an increased pressure in the internal space can be released and thereby define an opening forming arc-vent for the internal space. To protect against penetration of objects of a predetermined size into the electronic components, the cabinet further comprises a ventilation-open inner lining arranged in the internal space to cover the opening. If arching should occur, the increased pressure may rupture the line and the opening will allow venting. In this situation, the inner lining prevents against penetration.

Abstract: A detachable reinforcement tool (1) for providing temporary reinforcement of a rear frame structure (6) for a nacelle of a wind turbine is disclosed. The rear frame structure (6) comprises a plurality of truss members (4) and a plurality of joints (5), each joint (5) interconnecting ends of at least two truss members (4). The reinforcement tool (1) comprises a reinforcement part (2), and attaching means (3) for detachably attaching the reinforcement part (2) to two different parts (4, 5) of the rear frame structure (6). The reinforcement tool (1) is arranged to provide a load transferring connection between two parts (4, 5) of the rear frame structure (6) when the reinforcement part (2) is attached to the two parts (4, 5) of the rear frame structure (6) by means of the attaching means (3). The rear frame structure (6) is capable of handling extreme loads without being designed to handle such loads permanently. Manufacturing costs and weight of the rear frame structure (6) are reduced.

Abstract: The invention relates to techniques for verifying a nacelle yaw position sensor installed on a wind turbine and for taking restorative action to control the nacelle yaw position. The invention relates to a method performing the comprising determining a first absolute wind direction signal associated with the first wind turbine; determining a second absolute wind signal direction signal associated with the plurality of other wind turbines; comparing the two wind direction signals; and issuing a nacelle yaw position sensor fault signal if the first signal is beyond a predetermined error range of the second signal. A benefit of the invention is that it enables the detection of an inaccurate nacelle yaw sensor without direct measurement or inspection.

Abstract: Embodiments of the present disclosure generally relate to apparatus and methods for preventing power dips associated with power ramping in wind turbines. One embodiment of the present disclosure provides a method for stabilizing power output in a wind turbine, which includes tracking a rate of change in an external reference, such as an external power reference or external torque reference, computing a feed-forward pitch angle adjustment according to the rate of change in the external power reference, and sending the feed-forward pitch angle adjustment to the wind turbine to adjust a pitch angle of rotor blades simultaneously with adjusting power output according to the external reference.

Abstract: A method is disclosed for controlling a wind turbine generator to provide power above a rated level. The wind turbine includes one or more electrical components that conduct current from the internal generator to supply the external grid. The control method calculates the maximum current that the electrical components can carry at the ambient temperature. The calculated current is combined with a measurement of the voltage and an estimate of reactive power in the system to give a maximum power at which the wind turbine can operate without the maximum allowable current being exceeded for the electrical components. The electrical components may be housed in the main electrical panel of the wind turbine.

Abstract: A method is provided of protecting a wind turbine with a doubly-fed induction generator (DFIG) against a sub-synchronous resonance (SSR) event acting on the wind turbine. A plurality of power-output values or current-output values is measured over a given period of time that corresponds to a measurement cycle. It is determined whether power-output values or current-output-values measured in the at-least-one measurement cycle are indicative of an SSR-event critical for further operation of the wind turbine. The wind turbine is shut down if the measured power-output values or current-output values are indeed indicative of an SSR-event critical for operation of the wind turbine.

Abstract: A method for controlling a wind power plant, the wind power plant including a plant controller for controlling a plurality of wind turbine generators. The method for controlling a wind power plant allows the wind power plant to continue operating through a grid fault in a weak grid environment. In the method, a fault recovery process is carried out with a wind turbine power controller during a wind turbine fault recovery state to determine a grid voltage (VWTG), compare the grid voltage to a predetermined reference voltage (Vref) to obtain a difference value, and determine a current reference (QrefVC) based on the difference value for generating a reactive current (Idref) for regulating the grid voltage to the predetermined reference grid voltage. A corresponding wind power plant is further provided.