Patent Description:
A horizontal axis wind turbine is known to have an electric generator in a nacelle on top of a tower, where a rotor with a substantially horizontal axis mounted to the nacelle and arranged to drive the generator. The nacelle is usually arranged to be rotated in relation to the tower, to point the rotor towards the wind.

With growing sizes of horizontal axis wind turbines, challenges in handling of components for the wind turbines, e.g. at installation or service, increase. For example, such handling may require the use of very large cranes, which may cause increased costs with an increased usage time.

<CIT> relates to a method for assembling a wind turbine with a drive train and a nacelle, the outside of which is formed at least partially by at least one shell segment in the fully assembled state, with a partially assembled nacelle being mounted on an already erected supporting structure, comprises the following steps: The shell segment and at least one component of the drive train are attached together to a single load handling device and are lifted in a single lifting process by a hoist.

It is an object of the present invention is to facilitate the handling of wind turbine components. It is a further object of the invention to reduce the installation time of a wind turbine component.

The objects are reached with a method according to claim <NUM>. Thus, the invention provides a method for installing or removing components of a wind turbine. The method comprises separately fastening two or more wind turbine components to a respective receiving structure of the wind turbine, or separately releasing the components from the respective receiving structure. The method further comprises, before the fastening of the components, or subsequently to the releasing of the components, lifting the components simultaneously, so as to be carried by a lifting line of a crane. The directional inter-relationship of the components, during the lifting of the components, is substantially the same as the directional inter-relationship of the components when fastened to the respective receiving structure.

Separately fastening the components to the respective receiving structure, may comprise individually fastening the components to the respective receiving structure. Separately releasing the components from the respective receiving structure, may comprise individually releasing the components from the respective receiving structure.

Fastening the components to the respective receiving structure may provide for the components being finally installed in the wind turbine. Fastening the components to the respective receiving structure may provide for the components being secured in the wind turbine.

Lifting two or more components at the same time, will save installation time. Further, since the directional inter-relationship of the components, during the lifting of the components, is substantially the same as the directional inter-relationship of the components when fastened to the respective receiving structure, the components will be, when installed, lined up when reaching the receiving structures, as they are lined up when finally installed. Thereby, the need to move the components in relation to each other, in order to reach their respective receiving structure, may be minimised. In addition, the need to move the components in relation to each other, when removing them from the wind turbine, may be minimised. This will reduce the installation time of wind turbine components.

Preferably, the spatial inter-relationship of the components, during the lifting step, is substantially the same as the spatial inter-relationship of the components when fastened to the respective receiving structure. Thus, the position of one of the components in relation to the position(s) of the other component(s) will be substantially the same during the lifting step, as when the components are fastened to the respective receiving structure. Thereby, the components may be lifted with the spatial inter-relationship of their final installation.

Thereby, the need to move the components in relation to each other, in order to reach their respective receiving structure, or when removing them from the wind turbine, may be further minimised or even eliminated.

It should be noted that in some embodiments, as exemplified below, the distance between the components may be slightly larger or smaller during the lifting step compared to the distance between the components when fastened to the respective receiving structure. However, herein, even if there is a small such distance deviation, the spatial inter-relationship of the components, during the lifting step, is still considered to be substantially the same as the spatial inter-relationship of the components when fastened to the respective receiving structure.

The components are arranged, during the lifting of the components, one above the other. Thereby, the directional inter-relationship of the components may be that the one of the components that is above the other one, when the components are lifted, is also above the other one when the components are fastened to the respective receiving structure. Thereby, the components may be lifted in a vertical stack. Thereby, the components may be installed one on top of the other. A wind turbine may present a plurality of components installed one on top of the other. For example, components installed one on top of the other in the nacelle. By lifting the components, one on top of the other, the operating time of the crane may be reduced. Thereby, the overall installation time and cost may be reduced.

In some embodiments, fastening the components comprises fasting one of the components while the at least one other component is still carried by the lifting line. Thereby, a sequential fastening of the components is made provided. This will allow an accurate positioning of the components during installation. Also, this will allow a smooth installation procedure. Similarly, releasing the components may comprise releasing one of the components while the at least one other component is carried by the lifting line. This will allow a smooth component removal procedure.

Preferably, a lifting device is arranged to be suspended in the lifting line, the components being suspended, during the lifting of the components, individually from the lifting device. Thereby, the components could be suspended individually from the same lifting equipment. This will facilitate fasting one of the components while the at least one other component is still carried by the lifting line. Also, releasing one of the components while the at least one other component is carried by the lifting line may be facilitated by the individual suspension from the lifting device. The lifting device could be a lifting yoke. The lifting device could be a crane hook. The lifting device could be a combination of a lifting yoke and a crane hook.

Preferably, where, during the lifting step, a lower of the components is lifted below an upper of the components, the upper component presents one or more through openings. Thereby, one or more suspension lines, with which the lower component is suspended from the lifting device, may extend through a respective of the one or more through openings. Thereby, individual suspension of the components is facilitated, even if the upper component is interposed between the lower component and the lifting device.

Preferably, where, during the lifting step, a lower of the components is lifted below an upper of the components, the vertical distance between the lower and upper components is larger or smaller during the lifting step, than when fastened to the respective receiving structure. Preferably, during fastening or releasing of the lower component, to or from the receiving structure for the lower component, the upper component is above a position which the upper component has when the upper component is fastened to the receiving structure for the upper component.

This is particularly advantageous when a lifting device is arranged to be suspended in the lifting line, and the components are suspended, during the lifting step, individually from the lifting device. Where the vertical distance between the components is larger during the lifting step, than when finally installed, the lower component may be fasted to its receiving structure, while the upper component is still suspended from the lifting line. The shorter distance may be accomplished by suspension lines between the upper component and the lifting device, e.g. the lifting yoke, being shorter than needed to provide exactly the same inter-component distance as when the components are finally installed. When the lower component is fastened, the suspended upper component may be easily manipulated to be correctly positioned for being fastened to its receiving structure. When the lower component is fixed, the upper component may be lowered to its receiving structure. This allows for an accurate and smooth installation procedure.

Similarly, during component removal, the upper component may be released from its receiving structure, while the lower component is still fixed to its receiving structure. Subsequently, the upper component may be lifted, and allow to be suspended from the lifting line, while the lower component is released from it receiving structure. This allows for a smooth component removal procedure.

It should be noted that where the vertical distance between the components is smaller during the lifting step, than when the components are finally installed, the upper component may be fasted to its receiving structure, while the lower component is still suspended from the lifting line.

According to the invention, during the lifting step, a lower of the components is lifted below an upper of the components, and the lower component is suspended from the crane lifting line, e.g. via a lifting device such as a lifting yoke, the upper component is at least partly supported on the lower component. Thereby, the upper component is at least partly supported on the lower component via at least one support element. The support element may be provided in any suitable form, e.g. a leg, or some other form of distance device. Thus, the upper component rests, at least partly, on the first component. In some embodiments, the lower component supports the full weight of the upper component, so that the upper component may rest fully on lower component. In other embodiments, a part of the weight of the upper component may be carried by suspension lines extending from the upper component to a lifting device carried by the lifting line. Thereby, a safe environment may be provided for staff working under the upper component, before the latter is fastened, e.g. while fastening the lower component.

Where the upper component is at least partly supported on the lower component, the components could be removed as follows: The upper component may be lifted, e.g. by suspension lines to a lifting device carried by the lifting line. Subsequently, the one or more support elements may be placed on the lower component. Subsequently, the upper component may be lowered, so as to rest on the support element(s). Subsequently, the lower component may be lifted, suspended from the crane lifting line, while the upper component is supported on the lower component.

A first of the components may be a main component adapted to be housed in a nacelle of the wind turbine. The wind turbine main component may be a generator, a transformer, an electrical cabinet, a drivetrain component, or a combination thereof. The drivetrain component may be a gearbox, a rotor shaft, a main bearing housing, or any combination thereof. In some embodiments, the first component may be an assembled drivetrain for the wind turbine. The drivetrain may include a rotor shaft, a main bearing housing, and a gearbox. A second of the components may be a roof element of the nacelle or a part of the roof of a nacelle. The roof may be a canopy, a roof section, a covering panel, or a hatch for the nacelle of the wind turbine. The roof element may be lifted above the main component. Thereby, a particular advantage is obtained in certain wind turbine component removal and installation procedures. When removing and/or installing the main component, the nacelle roof element may be removed to access the main component from above. Removing the roof element first, and lowering it to the ground, and subsequently removing the main component, requires a relatively large amount of time, and therefore cost. Embodiments of the invention provides for lifting the roof element together with the main component, thereby saving time. In addition, since the roof element may be lifted above the main component, they are lifted with the same directional inter-relationship as they have when installed. Thereby, the components do not need to be moved to any substantial degree, in the wind turbine, before or after the lifting step.

Also, where the roof element (also herein called roof covering device) is lifted above the main component, the main component may obtain an increased protection against weather elements, during an installation or removal process. For example, embodiments of the invention allows for the nacelle to be closed immediately, or shortly, after the main component has been installed. This will reduce the risk of the main component being damaged by rain or snow entering the nacelle before the roof covering device has been installed.

Preferably, an area to mass ratio of a first of the components is less than <NUM>% of an area to mass ratio of a second of the components. Preferably, the area to mass ratio of the first component is less than <NUM>%, more preferably less than <NUM>%, for example approximately <NUM>%, of the area to mass ratio of the second component. Each area to mass ratio may be a maximum area of a two-dimensional projection of the respective component, divided by the mass of the respective component. Where the second component is relatively light, and has relatively large dimensions, a lifting operation with the second component alone may be difficult, e.g. due to wind gusts moving the component. This may form a safety issue. By lifting the second component together with the first component, which has an area to mass ratio of less than <NUM>% of the area to mass ratio of the second component, the second component may be stabilised by the first component, during the lifting step. Thereby, the lifting operation may be improved. The second component may be lifted above the first component. The first component may thereby service to stabilise, or anchor, the second component. Thereby, safety may be increased.

Below, embodiments of the invention will be described with reference to the drawings, in which.

Reference is made to <FIG>. A wind turbine <NUM> may include a foundation <NUM>, and a tower <NUM> coupled to the foundation <NUM> at a lower end thereof. A nacelle <NUM> may be disposed at the apex of the tower <NUM>. A rotor <NUM> may be operatively coupled to a generator housed inside the nacelle <NUM>. The rotor <NUM> of the wind turbine <NUM> may serve as the prime mover for a electromechanical system of the wind turbine. In addition to the generator, the nacelle <NUM> may house miscellaneous components required for converting wind energy into electrical energy. The nacelle <NUM> may also house various components needed to operate, control, and optimize the performance of the wind turbine <NUM>. While an on-shore wind turbine <NUM> is illustrated in <FIG>, it should be recognised that aspects of the present invention may also be used for off-shore wind turbines as well. The rotor <NUM> of wind turbine <NUM> may include a central hub <NUM> and at least one blade <NUM> that projects outwardly from the central hub <NUM>. In the representative embodiment, the rotor <NUM> includes three blades <NUM>, but the number may vary. The wind turbine may be a horizontal-axis wind turbine. The blades <NUM> may be configured to interact with the passing air flow to produce lift that causes the rotor <NUM> to rotate about a substantially horizontal axis <NUM>.

<FIG> shows a cross-section of the nacelle <NUM>. A rotor shaft <NUM> may be supported by two or more bearings in a shaft housing <NUM>, herein also referred to as a main bearing housing. The rotor shaft <NUM> may be arranged to connect the rotor <NUM> to a gearbox <NUM>. The generator <NUM> may be connected to the gearbox <NUM> via a high speed shaft <NUM>.

The nacelle may be connected to the tower <NUM> via a yaw system. The yaw system may include a yaw bearing <NUM>. The shaft housing <NUM> may be mounted on top of the yaw bearing <NUM>.

The nacelle <NUM> may comprise a lower nacelle structure <NUM>. The lower nacelle structure may be fixed to the shaft housing <NUM>. The lower nacelle structure <NUM> may support the gearbox <NUM>. Thereby, the lower nacelle structure <NUM> may form what is herein referred to as a receiving structure for the gearbox <NUM>.

A generator support structure <NUM> may be arranged to support the generator <NUM>. Thereby, the generator support structure <NUM> may form what is herein referred to as a receiving structure for the generator <NUM>. The generator support structure <NUM> may be supported by the lower nacelle structure <NUM>.

The nacelle <NUM> may comprise a shell <NUM>. The shell <NUM> may enclose the components in the nacelle. On a top side of the nacelle <NUM>, the shell <NUM> may present an opening <NUM>. In this example, the opening is located above the generator <NUM>. The size of the opening <NUM> may be adapted to lifting the generator <NUM> though the opening. The nacelle may further comprise a covering panel <NUM>, adapted to cover the opening <NUM>. A plurality of posts <NUM> may form a receiving structure for the covering panel <NUM>. The posts <NUM> may be supported by the generator support structure <NUM>. In this example, the receiving structure for the covering panel <NUM> comprises four posts <NUM>.

<FIG> shows a crane <NUM>. The crane may comprise a lifting line <NUM>. A lifting device, e.g. a yoke <NUM>, may be suspended from the lifting line <NUM>. The crane might be used for installing or removing components of the wind turbine <NUM>.

The crane may comprise an undercarriage <NUM>. The undercarriage may be arranged to be supported by the ground. The crane may be a mobile crane. The crane may comprise an over carriage <NUM>. The over carriage <NUM> may be arranged over the under carriage <NUM>. The over carriage <NUM> may be connected to the undercarriage <NUM> via a slewing bearing <NUM>. The over carriage <NUM> may be arranged to rotate, around a substantially vertical axis, in relation to the undercarriage <NUM>, by means of the slewing bearing <NUM>.

The crane may comprise an elongated boom assembly <NUM>. The boom assembly may be mounted on the over carriage <NUM>. The boom assembly may comprise one or more boom segments <NUM>, <NUM>. The boom assembly may comprise a first boom segment <NUM>, and a second boom segment <NUM>, as exemplified in <FIG>. The first boom segment may form a main boom <NUM>. The second boom segment may form a jib <NUM>. A lower end of the second boom segment <NUM> may be, in an erected condition of the boom assembly, connected to an upper end of the first boom segment <NUM>. The second boom segment lower end may be connected to the first boom segment upper via a flexible segment joint <NUM>. This may allow luffing of the second boom segment in relation to the first boom segment. Luffing may be performed by means of a jib guy line <NUM>. The boom assembly <NUM> may be connected to the over carriage <NUM> via an assembly joint <NUM>. More specifically, a lower end of the first boom segment <NUM> may be connected to the over carriage <NUM> via the assembly joint <NUM>. This may allow luffing of the first boom segment <NUM> in relation to the over carriage <NUM>. Such luffing may be performed by means of a boom guy line <NUM>.

The crane may be adapted to keep a load <NUM>, <NUM> suspended from the boom assembly. In this example, the load comprises a plurality of components for the wind turbine. More specifically, in this example, the load comprises the generator <NUM> and the covering panel <NUM>, as exemplified further below. The load <NUM>, <NUM> may be suspended from the lifting device <NUM>. The crane <NUM> may be adapted to keep the load <NUM>, <NUM> suspended from the second boom segment <NUM>. The crane may be adapted to keep the load suspended from an upper end of the second boom segment <NUM>. The crane may be adapted to carry the load <NUM>, <NUM> by means of the lifting line <NUM>. The height of the load <NUM> may be controlled by a winding drum <NUM>. The winding drum <NUM> may be provided on the over carriage <NUM>. Thus, the winding drum <NUM> may be arranged to reel the lifting wire <NUM> in or out.

With reference to <FIG>, an embodiment of a method according to the invention, for installing wind turbine components, will be described.

The components <NUM>, <NUM> may be placed on the ground. The lifting device <NUM> may be arranged to be suspended from a crane hook <NUM>, for example as depicted in <FIG>. The components in this example are the generator <NUM>, and the covering panel <NUM>. The components are here also referred to as a first and a second component <NUM>, <NUM>. The components are arranged so as to be suspended, during the lifting of the components, individually from the lifting device <NUM>. The components may be arranged, during the lifting of the components, one on top of the other. For this, the second component <NUM> may be arranged to be suspended from the lifting device <NUM> by means of one or more second component suspension lines <NUM>, as exemplified in <FIG>. The second component suspension lines <NUM> may be slings, ropes, chains, or any other suitable type of lines. Thereby, the second component <NUM> may be rigged S1 to the lifting device <NUM> by means of one or more second component suspension lines <NUM>.

The second component may be the covering panel <NUM>. The covering panel may present a rectangular shape. Each of the second component suspension lines <NUM>, in this example four of them, may extend from a respective corner of the covering panel <NUM> to the lifting device <NUM>. The lifting device may be provided as an elongated, horizontal boom. Two of the second component suspension lines <NUM> may be connected to one end of the lifting device <NUM>, and two further of the second component suspension lines <NUM> may be connected to the other end of the lifting device <NUM>.

Subsequently, the second component <NUM> may be moved S2 by means of the crane to a position above the first component <NUM>. Thereby, the second component <NUM> may be suspended from the lifting device <NUM> by means of the second component suspension lines <NUM>. Subsequently, the first component <NUM> may be arranged to be suspended from the lifting device <NUM> by means of one or more first component suspension lines <NUM>, as exemplified in <FIG>. The first component suspension lines <NUM> may be slings, ropes, chains, or any other suitable type of lines. Thereby, the first component <NUM> may be rigged S3 to the lifting device <NUM> by means of one or more first component suspension lines <NUM>.

The first component may be the generator <NUM>. Each of the first component suspension lines <NUM>, in this example four of them, may extend from a respective fastening device, e.g. an ear, on the generator <NUM> to the lifting device <NUM>. Two of the first component suspension lines <NUM> may be connected to one end of the lifting device <NUM>, and two further of the first component suspension lines <NUM> may be connected to the other end of the lifting device <NUM>.

Connecting the first component suspension lines <NUM> to the lifting device may be done while the second component <NUM> is positioned over the first component <NUM>. The second component <NUM> may present one or more through openings <NUM>. Thereby, the first component suspension lines <NUM> may extend through a respective of the through openings <NUM>.

Subsequently, the stacked components <NUM>, <NUM> may be lifted S4. The stacked components may be lifted to their installation position. Thereby, the components are lifted simultaneously, so as to be carried by the lifting line <NUM>. Thereby, the directional inter-relationship of the components <NUM>, <NUM>, during the lifting of the components, may be substantially the same as the directional inter-relationship of the components when fastened to the respective receiving structure <NUM>, <NUM> in the wind turbine, (<FIG>). More specifically, in this example, the first component <NUM> is lifted below the second component <NUM>, and the first component is below the second component when the components are fastened to the respective receiving structure. The first component <NUM> may also be referred to as the lower component, and the second component <NUM> may also be referred to as the upper component. The spatial inter-relationship of the components, during the lifting of the components, may be substantially the same as the spatial inter-relationship of the components when fastened to the respective receiving structure.

In some embodiments, the crane hook <NUM> may form a lifting device <NUM>. Thereby, the components may be arranged so as to be suspended, during the lifting of the components, individually from the crane hook <NUM>.

The area to mass ratio of the first component <NUM>, e.g. a generator, may be considerably smaller than the area to mass ration of the second component <NUM>, e.g. a cover panel. Preferably, an area to mass ratio of the first component <NUM> is less than <NUM>% of an area to mass ratio of the second component <NUM>. Herein, each area to mass ratio is a maximum area of a two-dimensional projection of the respective component, divided by the mass of the respective component. Thereby, the first component may serve to anchor the second component during the lifting of the components, as also discussed above. Thereby, the lifting procedure may be less sensitive to wind gusts, etc., tending to disturb the second component <NUM>, presenting a relatively high area to mass ratio.

It should be noted that each of the components <NUM>, <NUM> may be connected to the lifting device <NUM> with any number of suitable suspension lines <NUM>, <NUM>, for example two, three, four, or more. In some embodiments, the crane hook <NUM> could form the lifting device. Thereby, the suspension lines <NUM>, <NUM> could be joined in the crane hook <NUM>. In some embodiments, the lifting device could comprise one or more master links or similar equipment. Thereby, the suspension lines could be joined to the crane hook by means of the master link(s). The master link may be a ring, for example oval in shape, for connecting a plurality of the suspension lines. The master link may allow the suspension lines to be attached to the crane hook.

It should be noted the components could be any suitable type of wind turbine components. For example, the first component may be nacelle main component, such as a gearbox, a generator, a main bearing housing, or any combination thereof. For example, the second component could be nacelle roof covering device, such as a canopy, a nacelle roof section, a covering panel, or a hatch for the wind turbine nacelle.

Subsequently, the components may be fastened to their respective receiving structure, in this example in the nacelle <NUM>, (<FIG>). For this, the first component <NUM> is positioned on its receiving structure <NUM>, for example as shown in <FIG>. Subsequently, the first component <NUM> is fastened S5 to the receiving structure <NUM> for the first component.

Preferably, the distance between components <NUM>, <NUM> is larger during the lifting of the components, than when fastened to the respective receiving structure. Preferably, this difference in distance is relatively small. The difference between the distance between the components during the lifting of the components, and the distance between the components when the components are fastened to the respective receiving structure, may be at least one order of magnitude smaller than the largest extension of the components. Thereby, the spatial inter-relationship of the components, during the lifting of the components, may be substantially the same as the spatial inter-relationship of the components when fastened to the respective receiving structure.

As exemplified in <FIG>, where the distance between components <NUM>, <NUM> is larger during the lifting of the components, than when fastened to the respective receiving structure <NUM>, <NUM>, the second component <NUM> may be, during fastening of the first component to the receiving structure <NUM> for the first component, above a position which the second component <NUM> has when the second component is fastened to the receiving structure <NUM> for the second component. Therefore, the second component <NUM> may be still suspended when the first component <NUM> is fastened, and can still be manipulated into its position on its receiving structure <NUM>. Such manipulation is exemplified in <FIG> by the double arrows A, and B.

Thus, fastening the components comprises fasting one of the components while the at least one other component is still carried by the lifting line. Subsequently, the second component <NUM> is positioned on its receiving structure <NUM>, for example as shown in <FIG>. Thereby, the first component suspension lines <NUM> may be slacked, for example as shown in <FIG>. Subsequently, the second component <NUM> is fastened S6 to the receiving structure <NUM> for the second component. Subsequently, the suspension lines <NUM>, <NUM> may be detached from the components. Subsequently, the suspension lines <NUM>, <NUM> may follow the lifting device <NUM>, when the latter is moved away.

In embodiments of the invention, components are removed from a wind turbine. For example, with the components and devices described with reference to <FIG>, this could be done as follows:
The second component <NUM> may be rigged to the lifting device <NUM> by means of one or more second component suspension lines <NUM>. The first component <NUM> may be rigged to the lifting device <NUM> by means of one or more first component suspension lines <NUM>. Subsequently, the second component <NUM> may be released from the receiving structure <NUM> for the second component. Subsequently, the first component <NUM> may be released from the receiving structure <NUM> for the first component.

Subsequently, the stacked components <NUM>, <NUM> may be lifted. Thereby, the components may be lifted simultaneously, to be carried by the lifting line <NUM>, wherein the directional inter-relationship of the components, during the lifting of the components, is substantially the same as the directional inter-relationship of the components when fastened to the respective receiving structure.

Subsequently, the first component may be placed on the ground. Subsequently, the first component <NUM> may be released from the first component suspension lines <NUM>, while the second component <NUM> is carried by the lifting line <NUM>. Subsequently, the second component <NUM> may be moved by means of the crane away from the position above the first component <NUM>. The second component may be placed on the ground. Subsequently, the second component <NUM> may be released from the second component suspension lines <NUM>.

<FIG> depicts a further embodiment of the invention. During the lifting of the components, the upper component, i.e. the second component <NUM>, may supported on the lower component, i.e. on the first component <NUM>, via at least one support element <NUM>. The support element <NUM> may comprise more than one support component <NUM>, as exemplified in <FIG> or <FIG>. Thereby, the lower component <NUM> may be suspended from the crane lifting line <NUM>, and the upper component <NUM> may be supported on the lower component <NUM>. In some embodiments, additional control of the upper component <NUM> may be provided by way of e.g. upper component suspension lines <NUM>, connected between the upper component <NUM> and the lifting device <NUM>, while the upper component <NUM> is at the same time supported on the lower component <NUM>. Lifting lines <NUM> between a lifting device <NUM> and a lower component <NUM> may extend through openings <NUM> in an upper component <NUM>. In embodiments, the support element <NUM> may be retractable, in particular, a support component <NUM> of the support element <NUM> may be retractable. In particular, the support element <NUM> or support component <NUM> may be extendable and/or retractable. For example, a support component <NUM> may comprise a length adjuster <NUM> to extend or retract the length of a support component <NUM> of a support element <NUM>, thereby increasing or decreasing the effective separation distance between the upper and the lower component <NUM>, <NUM>. In one embodiment, the support element <NUM> may comprise multiple support components <NUM>. Preferably the support element <NUM> may comprise two support components <NUM> spaced apart, each supporting an opposite end of an upper component <NUM>. For example, one support component <NUM> may be positioned on each side of a gearbox <NUM>. A nacelle roof may be supported on top of the gearbox <NUM> via a pair of support components <NUM>.

Each support component <NUM> may preferably be length adjustable as mentioned to allow the upper component <NUM> to be lowered into its final position in a controlled manner. A length adjuster <NUM> of a support component <NUM> may comprise a jack, such as e.g. a hydraulic jack or a worm-screw type jack. In one embodiment, illustrated in <FIG>, a support component <NUM> comprises an upright pillar <NUM> extending between a lower component <NUM> and an upper component <NUM>. The upright pillar <NUM> may in particular be removably fixed to the lower component <NUM>. The upright pillar <NUM> may comprise an attachment foot <NUM>, for removable attachment to the lower component <NUM>. The attachment foot may be configured for direct attachment to a part of the lower component <NUM>. The pillar <NUM> may thereby be directly supported on the lower component <NUM>. In embodiments, a support shoe may be fitted to the lower component <NUM>. The attachment foot <NUM> may be supported on the support shoe of the lower component.

In the embodiment of <FIG>, the upright pillar <NUM> is in the form of a central column of the support component <NUM>, and may be telescopic. In particular, the telescopic upright pillar <NUM> may comprise a length adjuster <NUM> driven by a lead screw or hydraulic piston. By way of example, a lead screw may be driven by a motor at the upright pillar <NUM>. A lead screw drive motor may be provided at the foot <NUM> of a pillar <NUM>. The upright pillar <NUM> may house a gear unit. The lead screw for adjusting the length of the support component <NUM> may be driven from the gear unit. A gear unit may be housed at the foot <NUM> of the upright pillar <NUM>. A gear unit may be actuated by a drive motor in the upright pillar <NUM>. Alternatively, an external motor may be applied to the gear unit to drive the lead screw and actuate the extension or retraction of the length adjuster <NUM> and thereby of the support component <NUM>. For example, a hand drill may be used as a motor for the gear unit to actuate the jacking motion of the length adjuster <NUM>. Alternatively, the length adjuster <NUM> may be hydraulic. The length adjuster may comprise a hydraulic motor. A hydraulic motor may be housed in or at the upright pillar <NUM>. A hydraulic motor may be housed in or at the foot <NUM> of the upright pillar <NUM>. The length adjuster <NUM> may be actuated manually or using a control switching arrangement.

Optionally, the upper component <NUM> may be supported on a support element <NUM> via a lateral adjustment element <NUM>. In particular, the support element <NUM> may comprise one or more lateral adjustment elements <NUM> on which the upper component <NUM> rests during a lift. With the lower component <NUM> in position in the nacelle, the upper component <NUM> may then be brought into alignment for positioning precisely in its position. With the upper component <NUM> correctly aligned for positioning a length adjuster <NUM> at the support element <NUM> e.g. at a support component <NUM> thereof, may be actuated to retract the support component <NUM> thereby lowering the upper component <NUM> to its final position. With the upper component <NUM> in position e.g. on the wind turbine nacelle, the support element <NUM> and/or any other fastenings may be removed.

The interface between the upper component <NUM> and the support element <NUM> may include lateral adjustment elements <NUM> in the form of ball transfer units. These may optionally be retractable. When lateral adjustment of the position of the upper component is required, the ball transfer units may be brought into an extended position, in which these allow lateral positional adjustment of the upper component, even while keeping the upper component <NUM> supported on the support element <NUM>, during positioning thereof.

In addition to an upright pillar <NUM>, the support component <NUM> may include a lateral arm <NUM> joined to the upright pillar <NUM>. The lateral arm <NUM> may provide a support for the upper component <NUM> on the upright pillar <NUM>. The lateral arm <NUM> may extend from one lateral side of the upright pillar <NUM> or, preferably, it may extend away in opposite directions from the upright pillar <NUM>. The lateral arm <NUM> may be a compound arm, i.e. it may be articulated, e.g. at or near a mid-point thereof. The lateral arm <NUM> may articulated at a joint between the lateral arm <NUM> and the upright pillar <NUM>, e.g. at or near a mid-point thereof. The articulation may be a double articulation e.g. in the case of an arm <NUM> which extends away from the upright pillar <NUM> in two directions e.g. in opposite directions. The lateral arm <NUM> may be retractable. The lateral arm <NUM> may be supported on one or more buttresses <NUM> which extend between the lateral arm <NUM> and the upright pillar <NUM>. The buttresses <NUM> may be movable in translation up or down the support pillar <NUM>. The one or more buttresses <NUM> may be lockable in a support position at a location between an upper and a foot <NUM> of the upright pillar <NUM>. Hence, the support component <NUM>, and thereby the support element <NUM> may be collapsible e.g. for easy handling and storage when being assembled, dismantled, or when not in use.

Preferably, the upper and lower components <NUM>, <NUM> are fastened and suspended together such that lateral movement of the upper component <NUM> is constrained by the effect of the suspended mass of the lower component <NUM>. In particular, when the mass of the lower component is greater than the mass of the upper component. For example, a lateral gust of wind may tend to laterally urge the suspended upper component <NUM>, but this effect may be counteracted or neutralised by the resistance to lateral movement of the suspended lower component <NUM>. A resistance of the upper component <NUM> against lateral movement may be provided either by virtue of a support element <NUM> between the lower component <NUM> and the upper component <NUM> or by virtue of lifting lines <NUM> passing through the upper component <NUM>.

Claim 1:
A method for installing or removing components (<NUM>, <NUM>) of a wind turbine (<NUM>), comprising separately fastening two or more wind turbine components (<NUM>, <NUM>) to a respective receiving structure (<NUM>, <NUM>) of the wind turbine, or separately releasing the components (<NUM>, <NUM>) from the respective receiving structure (<NUM>, <NUM>), which comprises, before the fastening of the components (<NUM>, <NUM>), or subsequently to the releasing of the components, lifting the components (<NUM>, <NUM>) simultaneously, so as to be carried by a lifting line (<NUM>) of a crane (<NUM>), wherein the directional inter-relationship of the components, during the lifting of the components (<NUM>, <NUM>), is substantially the same as the directional inter-relationship of the components when fastened to the respective receiving structure (<NUM>, <NUM>) and wherein, during the lifting of the components (<NUM>, <NUM>), an upper component (<NUM>) is lifted above a lower component (<NUM>) wherein, during the lifting of the components (<NUM>, <NUM>), a lower of the components (<NUM>) is lifted below an upper of the components (<NUM>), and the lower component is suspended from the crane lifting line (<NUM>), characterized in that the upper component is at least partly supported on the lower component via at least one support element (<NUM>).