The present invention relates to a wind turbine assembly system which proposes an alternative to conventional cranes, having a main lifting structure configured to withstand the load of at least one tower section or at least one wind turbine component, and at least one secondary lifting structure configured to perform the lifting of the main lifting structure with respect to the wind turbine tower, in addition relating to a wind turbine assembly method according to the previous system, as well as the wind turbine assembled with the previous method.

A method and an arrangement for removing and lifting of a blade pitch slewing ring bearing of a wind turbine after a blade from a rotor hub of the wind turbine is removed, is disclosed. The arrangement and method enables the lowering and lifting of the wind turbine without the need of large and heavy cranes so that the replacement can be carried out cost effectively. The arrangement includes a first pulley mounted at the bottom of the wind turbine, a second pulley mounted inside a rotor hub, a lifting line running over the first pulley, the second pulley and further over a third pulley mounted inside a carrier. The carrier supports the blade pitch slewing ring bearing during lifting and lowering which is achieved through a coordinated operation of a ground winch, the lifting line and tag lines. Further, rigging equipment is attached to the lowered blade pitch slewing ring bearing to enable easy transportation.

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.

The present disclosure is directed to a hub crane assembly for a wind turbine. The hub crane assembly includes an adjustable articulating arm mountable at a first height on a hub of the wind turbine at a hinge point, a first hoist mountable at a second height of the wind turbine, the second height being greater than the first height, and a support component secured to the first hoist and a first attachment point of the articulating arm. Further, the first hoist is configured to rotate the articulating arm about the hinge point via the support component such that, as the articulating arm rotates, a clearance distance between the wind turbine and the articulating arm changes.

A nacelle component for a nacelle of a wind turbine, comprising a mainframe module and a power electronics module. The mainframe module and the power electronics module in each case have a length greater than a width. In the assembled state of the nacelle component, the mainframe module is oriented with its longitudinal axis parallel to a vertical plane which extends through the axis of a rotor shaft. The longitudinal axis of the power electronics module intersects the vertical plane which extends through the axis of the rotor shaft. A method for mounting such a nacelle component is also disclosed.

A method for mounting or dismounting a wind turbine component of an energy generating unit in a multirotor wind turbine is disclosed. The multirotor wind turbine comprises a tower configured to support one or more load carrying structures each arranged for supporting at least two energy generating units arranged at or near its ends and at opposite sides of the tower. The method comprises positioning or dispositioning a first wind turbine component at a first end of the load carrying structure, yawing the load carrying structure approximately 180 degrees, and positioning or dispositioning a second wind turbine component at the second end of the load carrying structure opposite the first end. The method may be used in erecting or servicing a multirotor wind turbine.

A method for performing maintenance on an outer surface of at least one wind turbine part, such as a tower (2), a nacelle (3) or a wind turbine blade (5), of an offshore wind turbine (1) is disclosed. An access system (10) is transported to a site of the offshore wind turbine (1), and the access system (10) is transferred to a transition platform (6) at a lower part of the offshore wind turbine (1), while operating the offshore wind turbine (1) in accordance with a normal operating mode. Normal operation of the offshore wind turbine (1) is then stopped, and maintenance is performed on an outer surface of at least one wind turbine part (2, 3, 5) of the offshore wind turbine (1), using the access system (10). When the maintenance has been completed, normal operation of the offshore wind turbine (1) is restarted in accordance with a normal operating mode. Normal operation of the offshore wind turbine (1) is only stopped while the actual maintenance takes place. Thereby the loss in power production is minimised.

A nacelle includes in turn a nacelle frame, and a yaw bearing having likewise/in turn at least a geared ring for providing a rotatable connection between the nacelle and the tower around a yaw axis. A method includes the steps of: a) disengaging the rotatable connection between the nacelle and the tower; b) lifting the nacelle from the tower by using lifting means, allowing the rotation of the geared ring; and c) rotating the geared ring around the yaw axis until the geared ring reaches a predetermined position with respect to the component to which the geared ring is connectable, either to the nacelle or the tower.

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).

The invention is a wind turbine tower and method of erection. The wind turbine tower comprises a plurality of support columns coupled to a wind turbine tower base, a lift deck coupled to the plurality of support columns configured to traverse a central longitudinal axis of the wind turbine tower, and a nacelle housing assembly coupled to the top of the plurality of support columns. The plurality of support columns spans a height of at least 85 meters may and in some embodiments are constructed of individual column segments transported and assembled via a small crane supported by the lift deck.