Abstract: A wind turbine blade includes a first blade portion and a second blade portion coupled together by a connection joint. A first spar cap is associated with an upper shell half and a second spar cap is associated with the lower shell half of each of the first and second blade portions. A shear web extends between the first spar cap and the second spar cap of each of the first and second blade portions. The shear web is terminated away from a joint interface at which the first and second blade portions meet, and there is no shear web extending in a longitudinal direction across the joint interface. The shear web extending between the first spar cap and the second spar cap is branched in the longitudinal direction toward the first and second blade interfaces of the first and second blade portions respectively.

Abstract: The invention relates to a wind turbine system with a plurality of wind turbine modules each with a rotor. A control system is arranged to execute a shutdown procedure with a first control command for terminating power production from a first subset of wind turbine modules resulting in a thrust force change with a reduced thrust force from the wind on a first part of the support structure carrying the first subset of wind turbine modules. A second control command is applied to a second subset of wind turbine modules for enabling thrust control of the second subset of wind turbine modules to oppose the thrust force change at the first part. Thus, there is obtained an improved and cost-effective way of stabilizing a wind turbine system with multiple rotors during shutdown.

Abstract: A wind turbine (1) comprising a tower (2) and a nacelle (3) mounted on the tower (2) is disclosed. A movable container (39) is mounted on a lower part of the nacelle (3) or suspended below the nacelle (3), the movable container (39) housing a hoisting mechanism for hoisting and/or lowering the movable container (39) and for hoisting and/or lowering wind turbine components (9, 10, 11).

Abstract: The present invention relates to a method for controlling a power plant for reducing spectral disturbances in an electrical grid being operative connected to the power plant, the power plant comprising a plant controller, at least one wind turbine and at least one auxiliary energy source, wherein the at least one wind turbine comprises a rotor adapted to drive a power generator via a shaft, wherein the generator is connectable with the electrical grid, and at least one damping controller configured to compensate structural oscillations of the wind turbine by controlling a torque on the shaft, wherein the at least one damping controller is capable of setting a limit of a control action on the shaft, the method comprising the steps of determining disturbance information for the power plant in the form of an electrical disturbance at a point of measurement electrically connected to the power plant, determining set-points for the at least one auxiliary energy source based on the determined disturbance information

Abstract: A wind turbine controller includes a thrust limiter for controlling the thrust of the blades of wind turbine using an estimate of the air density at the wind turbine. In one embodiment, the controller receives the blade flap load indicating the current load on one of the blades which varies linearly to the air density experienced by the wind turbine. In one embodiment, the controller determines the mean of a plurality of the blade flap load values measured during a predefined time period. Using a transfer function, the controller converts the mean of the blade flap loads to an estimate of the air density at the turbine. Generally, higher air density results in greater loads on the blades while lower air density results in lower loads on the blades.

Abstract: A method for wind turbine tower damping is disclosed, as well as an associated controller and wind turbine. The method comprises generating, using at least a first sensor signal, a first pitch reference signal for one or more rotor blades of a wind turbine during partial load operation. The method further comprises determining, using at least a second sensor signal, dynamic state information for a tower of the wind turbine. The method further comprises generating a second pitch reference signal by adapting the first pitch reference signal using the dynamic state information. The method further comprises selecting a maximum pitch reference signal from the second pitch reference signal and a saturation pitch reference signal. The method further comprises communicating the maximum pitch reference signal to control a pitch of the one or more rotor blades.

Abstract: A main computing system maintains and optimizes a predictive control model for an energy system, wherein the main computing system receives state information for the energy system, optimizes the predictive control model, and generates control rules for control of the energy system. The one or more local computing systems, each have a local memory for storing control rules for controlling the associated local state. The main computing system receives local state information and updates control rules, wherein the updated control rules comprise a subset of the control rules generated by the main computing system selected to be appropriate to the local state information received at the main computing system.

Abstract: The invention relates to a method for the controlled and automatic tensioning of bolts pre-installed in a flange joint between a hub and a main shaft in a nacelle of a wind turbine as well as to a bolt tensioning system for such method. The method comprises arranging a fixture inside the nacelle and mounting a bolt tensioning tool to the fixture which is mounted movable in an axial direction and in a working area perpendicularly hereto. First the flange joint is rotated to position a first set of bolts within the working area of the bolt tensioning tool, and then the bolt tensioning tool is controlled alternately to move the tensioning tool into a position for tensioning a bolt and to tension the bolt, until all bolts of the first set of bolts have been tensioned. The rotation of the flange joint may be controlled by operating a rotation tool operably connected to the main shaft, gearbox, and/or generator.

Abstract: A base frame assembly (24) for supporting a main shaft housing of a wind turbine comprises a base frame (50) having a plurality of mounting pads (42) for receiving the main shaft housing (20) thereon; and a brace component (52) comprising a plurality of arm portions (54), each arm portion (54) terminating in a respective support plate (56). Each one of the mounting pads (42) of the base frame (50) is configured to interface with and be secured to a corresponding one of the support plates (56) of the brace component (52).

Abstract: A method 400 of predicting tonal noise produced by a wind turbine is disclosed.

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 for use in controlling a wind turbine generator of a wind power plant based on a condition of a power converter or a component forming part of a power converter in the wind power plant. The method comprises determining the initial condition of the power converter or a component forming part of a power converter and determining the evolution of the condition from the initial condition based on notional power reference values of the wind turbine generator. The method further comprises comparing the evolution of the condition to a predetermined threshold and determining, from the comparison, a time period by which the condition of the power converter or a component forming part of a power converter will substantially equal the predetermined threshold.

Abstract: A wind turbine (1) comprising a tower (2) and one or more nacelles (3) mounted on the tower (2) is disclosed, at least one of the nacelle(s) (3) housing one or more drive train components (9,10,11) and a transportation system for moving drive train components (9,10,11) of the wind turbine (1). The transportation system comprises one or more sliding rails (15) configured to carry a drive train component (9, 10,11) during movement, and one or more sledges (19). Each sledge (19) is movably connected to a sliding rail (15), and configured to be attached to a drive train component (9,10,11), thereby allowing the drive train component (9,10,11) to move along the sliding rail(s) (15). Each sliding rail (15) comprises two or more rail modules (6,13,14) being detachably connected to each other along a direction of movement defined by the sliding rail (15).

Abstract: A nacelle for a wind turbine and a method for erecting a wind turbine are disclosed. The nacelle comprises a main unit arranged to be connected to a wind turbine tower, via a yawing arrangement, and at least one side unit mounted along a side of the main unit in such a manner that direct access is allowed between the main unit and the side unit(s), each side unit accommodating at least one wind turbine component, and at least one side unit being capable of carrying the wind turbine component(s) accommodated therein. The main unit and at least one of the side unit(s) are distributed side by side along a substantially horizontal direction which is substantially transverse to a rotational axis of a rotor of the wind turbine. A sufficient interior space of the nacelle is obtained while allowing the nacelle to be transported due to the modular construction. The weight of the wind turbine components is arranged close to the tower due to the transversal arrangement of the side unit(s) relative to the main unit.

Abstract: A method and a lifting arrangement for mounting a blade on a wind turbine rotor carried by a wind turbine structure. The method comprises providing a control line guide at the wind turbine structure, the control line guide forming a control line point configured to restrain the control line attaching the control line to the control line point; lifting the blade with an external blade lifting crane while a root end of the blade is guided towards the rotor by use of said control line restrained at said control line point, and connecting said blade to said rotor.

Abstract: A method for preparing a wind power facility for a transition from a first mode of operation to a second mode of operation includes the steps of specifying a set of operational parameters to be applied by the wind power facility in connection with the second mode of operation, said specified set of operational parameters being available for the wind power facility in response to a provided transition triggering signal, and providing the transition triggering signal and applying the specified set of operational parameters in the wind power facility in response thereto, wherein a subset of the specified set of operational parameters is applied in each of a plurality of wind turbine generators in response to the provided transition triggering signal. The first mode of operation may involve a normal mode of operation whereas the second mode of operation may involve an island mode of operation.

Abstract: An assembly, installation package and method for installing a wind turbine tower. The assembly (139) comprises an installation unit (114) having unit guides (140), each configured to engage a corresponding engagement guide (130) adjacent to an upper inner edge of the tower section (110) to guide the assembly while it is lowered into the tower section. The assembly also includes a yoke (136) releasably connected to the installation unit and comprising yoke guides (146), each configured to engage a corresponding engagement guide (130) adjacent to the upper inner edge of the tower section to guide the assembly while it is lowered into the tower section (110). The assembly (139) is configured such that at least one of the unit guides (140) and/or the yoke guides (146) is or are substantially continuously engaged with the engagement guides (130) from when the assembly (139) enters the tower section (110) until the assembly reaches its installation position within the tower section.

Abstract: A method is provided for braking a rotor of a wind turbine. The rotor comprises rotor blades. The wind turbine comprises a pitch adjustment system for adjusting a pitch of the rotor blades. The method comprises detecting a system failure of the pitch adjustment system, estimating a current wind speed, estimating an available brake torque and estimating a required brake torque, based on the estimated current wind speed. The method further comprises determining a suitable point in time for activating a rotor brake, based on the estimated available brake torque and the estimated required brake torque. The rotor brake is then activated at the determined suitable point in time.

Abstract: A method of forming a structural web for a wind turbine blade comprises providing a web member having a web portion and a flange portion extending away from each other, where 5 a heel of substantially curvilinear form is located between the web portion and the flange portion. A planar flange extender comprising a cured composite material is arranged together with the web member with the flange extender positioned adjacent to the flange portion so that a portion of the flange extender projects past the heel and away from the web portion. The flange extender is integrated with the web member in a resin matrix, or 10 with an adhesive, to form the structural web. A structural web and a wind turbine blade comprising the web is disclosed.

Abstract: A method for controlling a renewable energy power plant comprising a plurality of renewable energy generators, the method comprising: carrying out the following steps dynamically: determining a reactive power capability value of the power plant based on the generated active power of each of the renewable energy generators within the power plant; determining a reactive power exchange limit value based on a measured grid voltage level; and controlling the power plant so that the generated reactive power does not exceed the lower of the determined reactive power capability value and the determined reactive power exchange limit value that are determined dynamically.