A method for installing at least one damper unit in a tower section of a wind turbine tower is disclosed. The tower section is arranged with its centre axis in a substantially horizontal orientation, and a guiderail is introduced into the tower section. A trolley is mounted on a part of the guiderail extending out of the tower section, the damper unit is mounted on the trolley, and the trolley with the damper unit is moved along the guiderail to a position inside the tower section. The damper unit is positioned in an installation position being vertically offset from the centre axis of the tower section, wherein the positioning comprises elevating the damper unit, and the damper unit is attached to the tower section at the installation position.

A method of handling an auxiliary nacelle unit (24, 26) of a wind turbine (10) includes assembling a temporary hoist (52) on a main nacelle unit (22) by pivotally connecting a boom (64) to the main nacelle unit (22), pivotally connecting a mast (66) to the main nacelle unit (22), connecting the actuator (68) between the mast (66) and the boom (64), and routing a hoist cable (56) from a winch (54) to a hoist cable locator (60). The method further includes connecting the hoist cable (56) to an auxiliary nacelle unit (24, 26), activating the winch (54) to move the auxiliary nacelle unit (24, 26) from a first position to a second position, and activating the actuator (68) to move the boom (64) between the retracted position and the extend position. A lifting arrangement (50) for handling an auxiliary nacelle unit (24, 26) of a wind turbine (10) is also disclosed.

An apparatus is for performing parts of an operation to install a wind turbine, wherein the wind turbine has a tower, wherein the apparatus has a travelling car for travelling up and down along the tower for the wind turbine, and wherein the travelling car has a movable portion of a deck of the travelling car, wherein the movable portion of the deck is configured to carry an item to be installed as part of the wind turbine to a height for installation of the item and for moving the item substantially horizontally into a position for installation of the item when the travelling car is in a vertical position for installation of said item. Further is disclosed a method of installing at least a part of a wind turbine.

A wind turbine assembly includes a falling weight system to store potential energy within the wind turbine assembly. The falling weight system utilizes a pair of gears that can rotate to raise and lower weights within a cavity of the tower section. In addition, an assembly ring that is configured to climb a tower section of a wind turbine assembly may be used to assemble a wind turbine assembly or to perform maintenance on wind turbine assemblies. In some examples, a ballast weight system utilizing a ballast weight tank that lowers by being filled with water may be used to input rotational energy into a generator to create electricity.

A wind turbine (10) supported by a plurality of cables (20). The wind turbine (10) includes a tower (12). An energy generating unit (14) is disposed on the tower (12) and is configured to produce electrical energy from wind (40). The tower (12) includes an upper section and a lower section. Each of the upper and lower sections includes an inwardly directed flange (82, 90) having a plurality of through-bores (84, 92, 96). An annular member (62, 120) has one or more ears (50, 204) that extend outwardly. Each ear (50, 204) is configured to be coupled to one of the plurality of cables (20). The annular member (62) includes a plurality of bores (68, 72, 104) that align with the through-bores (84, 92, 96) in the inwardly directed flanges (82, 90). The bores (68, 72) each includes a screw thread (100, 102). Threaded fasteners (94) are used to secure the annular member (62, 120) to the tower (12). A method of installing includes tensioning cables (20) after installing the interface module (18, 120) on the tower (12) and before installing the energy generating unit (14).

A frustum connector for connecting wind turbine tower portions is provided, which frustum connector includes a plurality of individual steel segments, wherein each segment includes two side edges, an upper edge and a lower edge, wherein the length of the lower edge of a segment exceeds the length of the upper edge of that segment; and wherein the vertical side edges of adjacent segments are adapted for connection at a wind turbine installation site. A wind turbine tower and a method of constructing a wind turbine tower is also provided.

A windmill construction (10), comprising a rotor-nacelle assembly (12) with blades (14), a tower (16), a substructure (20) and a foundation (22). The substructure (20) comprises a first guide collar (24) and a second guide collar (26) for support of the tower (16), said first guide collar (24) being located in a lower part of the substructure (20) and said second guide collar (26) being located in an upper part of the substructure (20). The substructure (20) comprises a jack-up assembly (30) for receipt of modular tower segments (18), said tower segments (18) are arranged to be assembled in the substructure (20) and erectable by the jack-up assembly (30) to produce an assembled tower (16). The invention is also directed to a method for assembly of a windmill construction.

A method for installing at least one damper unit in a tower section of a wind turbine tower is disclosed. The tower section is arranged with its centre axis in a substantially horizontal orientation, and a guiderail is introduced into the tower section. A trolley is mounted on a part of the guiderail extending out of the tower section, the damper unit is mounted on the trolley, and the trolley with the damper unit is moved along the guiderail to a position inside the tower section. The damper unit is positioned in an installation position being vertically offset from the centre axis of the tower section, wherein the positioning comprises elevating the damper unit, and the damper unit is attached to the tower section at the installation position.

In an installation of a wind turbine on a floating foundation in floating condition and subject to sea-state induced motions, e.g. at the site of an offshore windfarm, use is made of a vessel with a crane arranged on the hull and provided with a hoisting system adapted to support the weight of the wind turbine and suspend the wind turbine from the crane. A heave compensation device compensates for sea-state induced heave motion of the wind turbine mast relative to the mast mounting structure of the floating foundation. Use is made of a mast alignment system configured to engage on the suspended wind turbine, e.g. on the mast of the suspended wind turbine, and to bring and maintain the mast of the wind turbine in alignment with the mounting axis of the floating foundation in order to compensate for sea-state induced motions, at least including tilt motions in one or more vertical planes, of the wind turbine mast relative to the mounting axis of the floating foundation.

A hybrid wind turbine tower includes at least one polygonal tower section with a polygonal cross-sectional profile connected to a foundation, at least one tubular tower section with a circular cross-sectional profile for connection to the nacelle, and a transition piece disposed between the at least one polygonal tower section and the at least one tubular tower section. The transition piece includes an upper portion having a circular cross-sectional profile connected to a lower end of the at least one tubular tower section, and a lower portion having a polygonal cross-sectional profile connected to an upper end of the at least one polygonal tower section. A method for assembling a hybrid wind turbine tower is also disclosed.