Abstract: Lubrication method and wind turbine comprising a rotor with a hub supported by a main bearing with two opposite bearing races coaxially spaced by rotatably fitted bearing rollers in a lubrication area which is sealed by oil sealing rings between the bearing races. The lubrication area comprises one or more oil inlets operatively connected to an oil supply, and one or more oil outlets. The vertical distance between the outlet(s) and the lowest point of the lubrication area is 0-0.2 times the inner diameter of the outer bearing race. The inlet (s) and the oil supply are configured to supply an oil flow not exceeding the drain capacity of the one or more outlets.

Abstract: A method and a system for generating auxiliary power for an islanded wind turbine are described, wherein the wind turbine may comprise a generator configured to provide power to a main grid. The method comprises: detecting an island mode of operation wherein said wind turbine is electrically disconnected from said main grid; in response to said disconnection, adjusting the rotational speed of said wind turbine to a value within a range of low rotational speeds; converting said generator output to a value suitable for charging said auxiliary power distribution system; and, connecting the output of said converter to said auxiliary power distribution system.

Abstract: A method and controller for controlling the torque in a wind turbine is described wherein the wind turbine is configured to deliver power via a converter to a public grid. The method comprises the steps of: receiving a fault signal; and, in response to said fault signal, a converter controller controllably ramping down the torque of said turbine from a nominal torque value to a predetermined low torque value within a predetermined time window selected from 0.2-2 seconds, preferably 0.5-1.5 seconds.

Abstract: A method and a system are described for island operation of at least two wind turbines associated with a wind farm, wherein said wind farm is configured for providing power generated by wind turbines in said wind farm to a main grid and wherein the method comprises: detecting at least two or more deactivated wind turbines in said wind farm, said deactivated wind turbines being disconnected from said main grid; configuring at least one islanded local grid for electrically connecting said two or more deactivated wind turbines; activating at least one of said deactivated wind turbine using a black start operation; and, connecting said at least one activated wind turbine and at least one of said deactivated wind turbines to said local grid, said activated wind turbine acting as a power supply for said at least one deactivated wind turbine connected to said local grid.

Abstract: The invention relates to a wind turbine of the horizontal axis, direct-drive type, wherein the wind turbine comprises a hub provided with one or more blades, a generator with a centerline that is technically horizontal, the generator comprising an inner rotor which is driven by the hub and an outer stator, the stator comprising a front plate, a back plate and stacked, arcuate laminates. The wind turbine according to the invention is characterized in that the front plate and the back plate are connected by tension rods so as to form a stator unit with the stacked, arcuate laminates being sandwiched between the back plate and the front-plate under compression, wherein of a first arcuate laminate in contact with a second arcuate laminate stacked against it the outer edge of the first arcuate laminate is at a larger distance from the centerline of the generator than the outer edge of the second arcuate laminate so as to increase the outer surface area of the stator for dissipating heat to the atmosphere.

Abstract: A wind turbine of the horizontal axis, direct-drive type, comprises a hub provided with one or more blades, a generator with a centerline that is technically horizontal, the generator comprising an inner rotor which is driven by the hub and an outer stator, the stator comprising a front plate, a back plate and stacked, arcuate laminates. The front plate and the back plate are connected by tension rods so as to form a stator unit with the stacked, arcuate laminates being sandwiched between the back plate and the front-plate under compression, the arcuate laminates having protrusions over the circumference of the stator for dissipating heat to the atmosphere. The invention also relates to a direct-drive generator.

Abstract: A protected turbine blade includes a first turbine blade shell and a second turbine blade shell, being fiber-reinforced, are connected by a cured resin and provided with a protective cover at a leading edge. The protective cover is a composite comprising a layer of UV-resistant thermoplastic material and a layer of cured epoxy resin, the UV-resistant thermoplastic material having the following properties a surface free energy of less than 35 mJ/m2, and a erosion resistance of the thermoplastic material larger than the erosion resistance of the cured resin connecting the turbine blade shells. The layer of cured epoxy-resin covers the cured resin over at least part of the length of the distal half of the turbine blade, and is bonded to said turbine blade. A method of manufacturing such a turbine blade, and to a turbine having such turbine blades is also provided.

Abstract: Wind turbine provided with a bearing supporting a hub carrying rotor blades, the bearing comprising a rotational bearing race connected to the hub and a stationary bearing race, a lubrication area between the bearing races which area is confined at both ends by first seal rings sealing the gap between the rotational bearing race and stationary parts to form a lubrication barrier. At one or both ends of the lubrication area a redundant seal ring is arranged at a distance from the first seal ring in or near the gap to be sealed.

Abstract: Wind farm comprising at least one buoyant structure having two corners provided with a wind turbine and a third corner comprising a mooring section, e.g., with a disconnectable mooring turret. The third corner does not carry one of the wind turbines. Shared facilities for the two wind turbines, such as a helideck and/or electrical equipment, such as a converter and/or transformer, can be located on or near the third corner.

Abstract: A method and a system for generating auxiliary power for an islanded wind turbine are described, wherein the wind turbine may comprise a generator configured to provide power to a main grid. The method comprises: detecting an island mode of operation wherein said wind turbine is electrically disconnected from said main grid; in response to said disconnection, adjusting the rotational speed of said wind turbine to a value within a range of low rotational speeds; converting said generator output to a value suitable for charging said auxiliary power distribution system; and, connecting the output of said converter to said auxiliary power distribution system.

Abstract: Wind turbine comprising a generator section with a generator rotor and a generator stator. A first air gap is defined between a first surface of the generator rotor and the stator, and magnets and electro conductive windings are provided at opposite sides of the first air gap to create a magnetic field over the first air gap during operation. The wind turbine comprises distance measurement means arranged to measure the radial length of a second air gap defined between a second surface of the generator rotor and a stationary part of the generator section. The second air gap is located at a radial distance from the first air gap at a position where there is no interference of a magnetic field generated by the magnets over the first air gap, and the length of the second air gap corresponds directly to the length of the first air gap. This enables accurate measurement and monitoring of the air gap length.

Abstract: Lubrication method and wind turbine comprising a rotor with a hub supported by a main bearing with two opposite bearing races coaxially spaced by rotatably fitted bearing rollers in a lubrication area which is sealed by oil sealing rings between the bearing races. The lubrication area comprises one or more oil inlets operatively connected to an oil supply, and one or more oil outlets. The vertical distance between the outlet(s) and the lowest point of the lubrication area is 0-0.2 times the inner diameter of the outer bearing race. The inlet (s) and the oil supply are configured to supply an oil flow not exceeding the drain capacity of the one or more outlets.

Abstract: Method of constructing a wind turbine comprising a tower with a bottom section housing electric equipment, which is built in the bottom tower section before the bottom tower section is positioned on a foundation. Prefabricated bottom tower section for a wind turbine comprising electric equipment, e.g., positioned on two or more floors.

Abstract: A method and a system are described for island operation of at least two wind turbines associated with a wind farm, wherein said wind farm is configured for providing power generated by wind turbines in said wind farm to a main grid and wherein the method comprises: detecting at least two or more deactivated wind turbines in said wind farm, said deactivated wind turbines being disconnected from said main grid; configuring at least one islanded local grid for electrically connecting said two or more deactivated wind turbines; activating at least one of said deactivated wind turbine using a black start operation; and, connecting said at least one activated wind turbine and at least one of said deactivated wind turbines to said local grid, said activated wind turbine acting as a power supply for said at least one deactivated wind turbine connected to said local grid.

Abstract: A wind turbine of the horizontal axis, direct-drive type, comprises a hub provided with one or more blades, a generator with a centerline that is technically horizontal, the generator comprising an inner rotor which is driven by the hub and an outer stator, the stator comprising a front plate, a back plate and stacked, arcuate laminates. The front plate and the back plate are connected by tension rods so as to form a stator unit with the stacked, arcuate laminates being sandwiched between the back plate and the front-plate under compression, the arcuate laminates having protrusions over the circumference of the stator for dissipating heat to the atmosphere. The invention also relates to a direct-drive generator.

Abstract: The invention relates to a wind turbine of the horizontal axis, direct-drive type, wherein the wind turbine comprises a hub provided with one or more blades, a generator with a centerline that is technically horizontal, the generator comprising an inner rotor which is driven by the hub and an outer stator, the stator comprising a front plate, a back plate and stacked, arcuate laminates. The wind turbine according to the invention is characterized in that the front plate and the back plate are connected by tension rods so as to form a stator unit with the stacked, arcuate laminates being sandwiched between the back plate and the front-plate under compression, wherein of a first arcuate laminate in contact with a second arcuate laminate stacked against it the outer edge of the first arcuate laminate is at a larger distance from the centerline of the generator than the outer edge of the second arcuate laminate so as to increase the outer surface area of the stator for dissipating heat to the atmosphere.

Abstract: Wind farm comprising at least one buoyant structure having two corners provided with a wind turbine and a third corner comprising a mooring section, e.g., with a disconnectable mooring turret. The third corner does not carry one of the wind turbines. Shared facilities for the two wind turbines, such as a helideck and/or electrical equipment, such as a converter and/or transformer, can be located on or near the third corner.

Abstract: A protected turbine blade includes a first turbine blade shell and a second turbine blade shell, being fibre-reinforced, are connected by a cured resin and provided with a protective cover at a leading edge. The protective cover is a composite comprising a layer of UV-resistant thermoplastic material and a layer of cured epoxy resin, the UV-resistant thermoplastic material having the following properties a surface free energy of less than 35 mJ/m2, and a erosion resistance of the thermoplastic material larger than the erosion resistance of the cured resin connecting the turbine blade shells. The layer of cured epoxy-resin covers the cured resin over at least part of the length of the distal half of the turbine blade, and is bonded to said turbine blade. A method of manufacturing such a turbine blade, and to a turbine having such turbine blades is also provided.

Abstract: Wind turbine provided with a bearing supporting a hub carrying rotor blades, the bearing comprising a rotational bearing race connected to the hub and a stationary bearing race, a lubrication area between the bearing races which area is confined at both ends by first seal rings sealing the gap between the rotational bearing race and stationary parts to form a lubrication barrier. At one or both ends of the lubrication area a redundant seal ring is arranged at a distance from the first seal ring in or near the gap to be sealed.

Abstract: A lubrication seal such as an oil seal is described for providing a lubrication barrier to confine lubrication in a bearing with a first bearing ring and second bearing ring, comprising a support ring that rotates with one of the bearing rings, mounted in the support ring are a first seal ring and a second seal ring which seal rings are suitable for forming the lubrication barrier with a sealing surface that rotates with the other bearing ring and which support ring is displaceable from a first sealing position in which the first seal ring forms the lubrication barrier with a first sealing area and the second seal ring does not engage the sealing surface to a second sealing position in which the second seal ring forms the lubrication barrier. The sealing surface comprises a second sealing area that only cooperates with the second seal ring after the support ring is displaced into the second sealing position.