Abstract: A method for operating a wind farm having a string (S1-S3) of wind turbines (100-100c) which are electrically connectable with each other and a grid (510, 550) is disclosed. Each wind turbine includes a rotor (106) with rotor blades (108), a power conversion system (118, 210, 238) mechanically connected with the rotor (106), and at least one auxiliary subsystem (105, 109).

Abstract: A method for operating a wind farm having a string (S1-S3) of wind turbines (100-100d) which are electrically connectable with each other and a grid (510, 550) via power connections (Cab-Cd) is disclosed. Each wind turbine includes a rotor (106) with rotor blades (108), and a power conversion system (118, 210, 238) mechanically connected with the rotor (106). The method includes disconnecting the string (S1-S3) from the grid (510, 550), and identifying a primary wind turbine (100a, 100c) of the disconnected string (S1-S3) which is electrically connectable with at least one secondary wind turbine (100b-10d) of the disconnected string (S1-S3). The power conversion system (118, 210, 238) of the primary wind turbine (100a, 100c) includes a reactive power capability (RPC) that at least matches a reactive power (RP) of a cluster (C1, C11, C12) to be formed by electrically connecting the primary wind turbine (100a, 100c) with the at least one secondary wind turbine (100b-100d) of the disconnected string (S1-S3).

Abstract: The present disclosure relates to methods (100, 200) for controlling and operating wind turbines (10). More particularly, the present disclosure relates to methods and systems for determining a surface condition of one or more wind turbine blades (22) of a wind turbine (10). a method comprises rotating the wind turbine rotor (18) under the influence of a wind in predetermined rotation conditions, wherein the predetermined rotation conditions include at least a predetermined pitch angle (252) of the additional wind turbine blades (222, 223). The method further comprises determining a current value of one or more parameters of the wind turbine (10) when rotating in the predetermined rotation conditions and comparing the current value of the one or more parameters of the wind turbine with one or more reference values (37) to determine the surface condition of the wind turbine blades (22).

Abstract: The present disclosure relates to electrical machines and methods for cooling active elements of electrical machines. More in particular, the present disclosure relates to rotors of electrical machines. An electrical machine may for example be a generator for a direct drive wind turbine. An electrical machine comprises a rotor comprising a plurality of active rotor elements, a stator comprising a plurality of active stator elements, and an air gap separating the active rotor elements and the active stator elements. The rotor further comprises one or more rotor openings configured for letting air flow enter the electrical machine and cool the active rotor elements and/or active stator elements in response to a rotation of the rotor.

Abstract: A rotor blade assembly for a wind turbine includes at least one rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root. The surfaces are constructed of a polymeric composite material. The rotor blade assembly also includes a protection cap arranged adjacent to one or more of the surfaces of the rotor blade so as to cover at least a portion of the one or more surfaces of the rotor blade. The protection cap includes a body defining an overall length. Further, at least a first segment of the protection cap is constructed of a tungsten-based metal. Thus, the protection cap is configured to reduce erosion and resist corrosion of the rotor blade caused by particle or liquid impact.

Abstract: A rotor blade assembly for a wind turbine includes at least one rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root. The surfaces are constructed of a polymeric composite material. The rotor blade assembly also includes a protection cap arranged adjacent to one or more of the surfaces of the rotor blade so as to cover at least a portion of the one or more surfaces of the rotor blade. The protection cap includes a body defining an overall length. Further, at least a first segment of the protection cap is constructed of a tungsten-based metal. Thus, the protection cap is configured to reduce erosion and resist corrosion of the rotor blade caused by particle or liquid impact.

Abstract: In a first aspect, a system for rotating an unbalanced direct drive wind turbine is provided. The system includes an auxiliary converter and a power source coupled to the auxiliary converter, wherein the auxiliary converter is configured to supply a current to the wind turbine generator for generating a torque to rotate the hub. In a further aspect, a method of rotating an unbalanced hub of a direct drive wind turbine is provided. In a yet further aspect, a method of installing a blade in a hub of a direct drive wind turbine is provided.

Abstract: In a first aspect, a system for rotating an unbalanced direct drive wind turbine is provided. The system comprises an auxiliary converter and a power source coupled to the auxiliary converter, wherein the auxiliary converter is configured to supply a current to the wind turbine generator for generating a torque to rotate the hub. In a further aspect, a method of rotating an unbalanced hub of a direct drive wind turbine is provided. In a yet further aspect, a method of installing a blade in a hub of a direct drive wind turbine is provided.

Abstract: A wind energy system is provided with said wind energy system including a hub pivotable about a rotation axis, a first bearing connected to said hub, a tapered adapter, a second bearing connected to said first bearing by said adapter, wherein said first and second bearings and said adapter are arranged such that the tilt angle of said rotation axis of said hub is adjustable. Further, a tilt adjustment system for a wind energy system and a method for operating a wind energy system is provided.

Abstract: A braking system for a wind turbine is provided. The system includes one or more motors for driving a part of the wind turbine, a first group of brakes for braking the part of the wind turbine, and a second group of brakes for braking the part of the wind turbine. The first group of brakes is in a normally closed condition and the second group of brakes is in a normally open condition, so that a default brake torque can be selectively chosen that is less than a maximum brake torque.

Abstract: A wind energy system is provided with said wind energy system including a hub pivotable about a rotation axis, a first bearing connected to said hub, a tapered adapter, a second bearing connected to said first bearing by said adapter, wherein said first and second bearings and said adapter are arranged such that the tilt angle of said rotation axis of said hub is adjustable. Further, a tilt adjustment system for a wind energy system and a method for operating a wind energy system is provided.

Abstract: A braking system for a wind turbine is provided. The system includes one or more motors for driving a part of the wind turbine, a first group of brakes for braking the part of the wind turbine, and a second group of brakes for braking the part of the wind turbine. The first group of brakes is in a normally closed condition and the second group of brakes is in a normally open condition, so that a default brake torque can be selectively chosen that is less than a maximum brake torque.

Abstract: A flange connection is provided which includes a first flange having a first mounting hole and at least one second flange having a second mounting hole adapted to be aligned with the first mounting hole. A bolt including a shaft portion having a threaded portion, and a head portion formed at one end of the shaft portion is adapted to pass through the first and second mounting holes. A screw nut is adapted to be screwed onto the threaded portion and for connecting, when tightened, the first flange and the at least one second flange. At least one of the head portion and the screw nut includes a convex surface which is oriented towards the respective flange, and the respective flange includes, at the mounting hole, a flange recess which is oriented towards the convex surface.

Abstract: A yaw bearing assembly includes a first component having a first sliding surface and a second sliding surface, and a brake assembly coupled with respect to the first component and adjacent to at least one of the first sliding surface and the second sliding surface. The brake assembly includes a piston, a sliding pad coupled to the piston, and an activation device coupled to the piston for moving the sliding pad with respect to at least one of the first sliding surface and the second sliding surface.

Abstract: A nacelle for a wind turbine generator includes a spaceframe having at least one exterior panel and at least one interior panel joined to the exterior panel. Each of the exterior and interior panels have a plurality of generally U-shaped channel portions with flanges extending outward from the channel portion. The flanges of the exterior panel are joined to the flanges of the interior panel to define a plurality of ribs, a plurality of joints, and a plurality of openings.