NL2025208B1

NL2025208B1 - Method and device for connecting a blade of a wind turbine to a hub

Info

Publication number: NL2025208B1
Application number: NL2025208A
Authority: NL
Inventors: Marc Aarts Robert; Antonius Alphonsus Geene Paul; De Vos Roland
Original assignee: Heerema Marine Contractors Nl
Priority date: 2019-11-26
Filing date: 2020-03-25
Publication date: 2021-08-30

Abstract

The present invention relates to a blade positioning system configured for positioning wind turbine blades at a hub of a nacelle of a wind turbine from an installation vessel at an offshore location, the blade positioning system comprising: the installation vessel comprising: — at least one lifting device configured for lifting wind turbine components, and — an auxiliary support tower extending upwardly from the installation vessel, the auxiliary support tower comprising: o a nacelle support for supporting the nacelle, o a root end moving assembly defining a guide path which extends over a vertical distance, the root end moving assembly comprising a movable root end support base and a root end support configured for supporting and guiding the root end of the blade, the root end support being connected to the movable root end support base, the root end support being movable along the guide path, the root end moving assembly being configured for moving the root end of the blade along the guide path from the engagement position to an installation position, the at least one lifting device being configured for lifting the nacelle onto the auxiliary support tower, wherein the at least one lifting device and the root end moving assembly are configured tojointly support and jointly move the blade upwards towards the hub, wherein during the movement the root end is supported by the root end support and the lifting device carries a majority of the vertical loads on the blade.

Description

P34263NLOO/WHA/RSM Title: Method and device for connecting a blade of a wind turbine to a hub

FIELD OF THE INVENTION The invention relates to the field of offshore wind turbine installation and in particular to a method and device for moving a wind turbine blade toward a hub of a nacelle, wherein the nacelle is positioned on a mast in an offshore environment, and wherein the blade is moved toward the hub with the help of a crane on an installation vessel.

BACKGROUND OF THE INVENTION In the field of offshore wind turbine installation, various methods of connecting the blades to a nacelle exist.

Many requirements and considerations apply to methods of connecting blades to a nacelle offshore. For instance, the total installation time is an important factor in the cost of installation. Further, weather conditions may impede the installation, and for this reason the installation time should be short.

Furthermore, safety issues are important, offshore installation methods generally carry a certain risk for personnel, and this risk should be minimized.

Furthermore, during installation, many different steps need to be carried out. As a whole the installation of a wind turbine at sea is quite complex, and reducing this complexity can result in an increase of safety and a reduction of costs.

Furthermore, there is a general tendency that wind turbines are ever-increasing in size and thus installation occurs at high elevation. Additionally, this means that the blades of these turbines also increase in size, and currently may have a length greater than 100m. With this increase in size, the handling becomes increasingly difficult.

Furthermore, there is a tendency to install wind turbines at increasing water depths. As jack-up rigs have limitations when it comes to water depth, an increase in water depth results in an increase in size of the jack-up rig. This in turn leads to an increase in jack-up time, resulting in higher costs.

An alternative to a jack-up rig is the use of a floating vessel. Although a floating vessel may be more adequate for large water depths, it is more susceptible to environmental conditions.

Furthermore, the environmental conditions at offshore wind turbine sites often involve high waves and strong winds. Preferably the installation method should allow for wind and waves and not be overly dependent on good weather.

All of these considerations make it difficult to create a method that is not only simple, fast and safe, but also cost efficient.

US2011/0056168A1 (hereinafter D1) discloses a method and device for the installation of a wind turbine, where the system consists of a hoisting platform and a carrier placed on a jack-up rig. The carrier is positionable along the hoisting platform and the hoisting platform is positionable along at least one of the jack up rig’s legs. The carrier can position a component for installation at a site where a foundation is present.

In one embodiment of D1, shown in figures 20-24, a blade handler is connected to the carrier and a blade is positioned in the handler. Subsequently, the blade is positioned adjacent a nacelle and tower unit placed on a foundation for installation thereto.

Once the blade is in the vertical position, see fig. 23, the carrier is moved along the hoisting platform such that the blade is horizontally aligned with the nacelle. The blade is then moved upwardly and connected to the nacelle. The nacelle may then be rotated, and the process is repeated for additional blades.

Although it appears that this method works, it was recognized in the present invention that this method has a number of drawbacks.

First, the location of the nacelle on top of the wind turbine tower means that the connecting of the blades to the nacelle must be carried out at a high elevation. This means that an operator situated on the deck of the vessel may not have a clear view of the root end connector of the blade. This may pose a problem when aligning the root end of the blade with the root end connector of the hub. This issue is emphasised due to the lack of a guidance system.

Furthermore, the blade needs to be rotated from a horizontal orientation to a vertical orientation during the lifting of the blade. In order not to damage the blade, significant care must be taken in order to avoid any collision with other objects situated on the deck.

In addition, the blade is not free to rotate about all three axes. This limits alignment options during the final step of installation. Where this is not a problem if the initial positioning in the blade handler is done right, it imposes a requirement on the quality of positioning and therefore will cost more time.

US2010/0293781A1 discloses an installation vessel and method for the installation of offshore wind turbines. In one embodiment, a cantilever mast is used to transfer components from a jack-up rig to an offshore installation site. In another embodiment, a crane is used in cooperation with a guide arm to transfer and guide components from an installation vessel to an offshore installation site.

In the first embodiment shown in figure 3, a nacelle comprising a hub is placed on a platform connected to a cantilever mast that is moveable about the deck of the installation vessel. The platform may translate in the vertical direction, along the cantilever mast. Subsequently, a blade is picked up by a blade handling crane and is positioned by that crane to be connected to the hub. Hereafter, the hub is rotated 120 degrees to allow installation of a subsequent blade. The nacelle is then positioned for assembly to the wind turbine tower by moving the cantilever tower to an adequate position.

In the second embodiment shown in figure 5, the blades are directly attached to a hub- nacelle assembly installed on the tower sections of the turbine, which in turn have been installed on the foundation of the turbine. A blade handling crane lifts a blade and places it in an elevator connected to the cantilever mast. This elevator then lifts the blade up to a desired height for the cantilever mast to move into position for the attachment of the blade to the hub. Hereafter, the hub is rotated 120 degrees to allow the installation of a subsequent blade.

Figures 7A-7E disclose a third embodiment in which a so-called tower trolley 730 is connected to the mast 15. The frame 730 is configured to support an RNA (Rotor Nacelle Assembly) The frame is configured to move the RNA upward to the top of the mast. See paragraphs 62-69.

It was recognized in the present invention that this method and its embodiments have several disadvantages. A first disadvantage relates to the first embodiment; the blade is solely handled by a blade handling crane. The fact that the assembly is performed only by a crane without any guidance system is difficult because the crane operator must position and align the blade at a significant distance from his own position. Furthermore, in this first embodiment, the use of a jack-up rig is necessary with respect to the influence of environmental conditions.

A disadvantage of the second embodiment lies in the fact that the cantilever tower and the elevator connected to it may only translate. This limits the ease, and therefore the speed, with which a blade can be connected to a hub.

Furthermore, the fact that only translations are possible, limits the use of the invention to a jack-up rig. Use of the invention on a floating vessel would be impossible as any wave motion would be passed along into a motion of the cantilever tower, and with that the blade root end connector.

A disadvantage of the third embodiment is that the entire RNA needs to be transferred to the tower trolley by the crane on the jack-up rig. This results in a considerable risk of collision between the RNA and the tower, in particular with high winds, because the gap between the RNA and the tower is quite small and there is little control over the movements of the RNA. Perhaps this operation is possible from a jack-up rig, although it would be quite risky. It is believed to be very risky or even technically impossible to carry out such an operation from a floating installation vessel. It is important to note that blades of a wind turbine are light constructions which are designed to catch wind. Blades are therefore very sensitive to wind.

This increases the risk of collision WO2013983614A1 discloses an invention relating to the assembly of a wind turbine at sea. The discloses device comprises lifting means adapted to place components on a foundation present in the sea, wherein the device further comprises a robot arm with a tool for the supporting of components, at least during placing thereof. Likewise, the invention relates to a method for assembling a wind turbine at sea.

The invention makes use of a crane and a robot arm for the installation of the blades to a hub that is connected to a nacelle that is placed on a turbine tower placed on a foundation present in the sea. The blade is lifted by the crane and is supported by the robot arm. The robot arm is used for the alignment between the lifted blade and the nacelle placed on the turbine tower.

Although it appears that this method seems to work, it was recognized in the present invention that this method has a number of drawbacks. First, while the use of a robot arm for the alignment of a blade to the nacelle is innovative, 5 the size of the blade makes that an already expensive piece of equipment like a robot arm must be able to handle extremely large items, further increasing costs of installing such a blade. Furthermore, the use of the invention is limited to a jack up rig; Use of the invention on a floating vessel would be extremely difficult as any wave motion would be passed along into a motion of the tower and should then be compensated by the robot arm.

OBJECT OF THE INVENTION lt is an object of the invention to provide an installation method and an installation device for installing wind turbine blades to a nacelle at sea which is relatively fast, safe, structured, reliable and cost-effective.

SUMMARY OF THE INVENTION In order to achieve the object, the present invention provides a method for connecting wind turbine blades to a hub of a nacelle of a wind turbine at or near an offshore target location, the method comprising the steps: a) positioning an installation vessel at the target location, the installation vessel comprising a lifting device configured for lifting wind turbine components, wherein the installation vessel further comprises an auxiliary support tower extending upwardly from a hull or deck of the installation vessel, the auxiliary support tower comprising: o a nacelle support for supporting the nacelle, o a root end moving assembly defining a guide path which extends over a vertical distance, the root end moving assembly comprising a movable root end support base and a root end support configured for supporting and guiding the root end of the blade, the root end support being connected to the movable root end support base, the root end support being movable along the guide path, the root end support being configured for engaging the root end of the blade in an engagement position thereof, the root end moving assembly being configured for moving the root end of the blade upward along the guide path from the engagement position to an installation position of the blade, b) positioning a nacelle comprising a hub on the auxiliary support tower,

c) engaging a blade with the root end support at the engagement position and moving the blade upwards towards the hub from the engagement position to the installation position in a joint operation of the root end moving assembly and the lifting device, wherein the root end is supported and guided by the root end support and the lifting device carries a majority of the vertical loads on the blade, d) connecting the root end of the first blade to the hub, e) repeating steps c) and d) for at least one subsequent blade, and in particular all blades, thereby forming either a complete rotor nacelle assembly (RNA) or a partial (RNA). The present invention advantageously allows the structured and safe assembly of turbine blades to a nacelle by making use of a relatively fast, safe and cost-effective procedure. Until now, such a procedure was not available. Given the ever increasing size of offshore wind turbine, the increasing depths at which those turbines are installed, and the difficulties accompanied by them, the present invention is a valuable contribution to this field of technology.

The lifting device carries the majority of the vertical loads on the blade (forces in the Z- direction). The vertical loads may comprise the weight and vertical forces resulting from vertical accelerations.

The root end moving assembly may carry the majority of horizontal loads in the longitudinal direction of the blade (forces in the X-direction).

The forces in a horizontal direction in a Y-direction (orthogonal to the longitudinal direction of the blade) may be carried by a combination of the crane, possible tugger lines and also the root end moving assembly.

Moments about the X-axis, Y-axis and Z-axis may be carried by a combination of the lifting device, one or more tugger lines and the root end moving assembly.

The words “extending upwardly from a hull or deck of the installation vessel” are to be interpreted broad. The auxiliary support tower does not need to be connected directly to the hull or deck, as long as it rises upward from the hull or deck.

The invention comprises a support structure, wherein, in one embodiment, the support tower is a tower extending upwardly from the hull or deck of an installation vessel. A nacelle support connected to this support tower is configured to temporarily support a nacelle during the connecting of one or more blades thereto.

This tower may be shorter than a turbine mast, with the result that installation may occur at low elevation.

In an embodiment the blade is held horizontally or substantially horizontally by the root end moving assembly and the lifting device during the lifting operation.

In an embodiment the blade is held horizontally or substantially horizontally by the root end moving assembly and the lifting device during the positioning operation

In a further, independent aspect, the invention relates to a method for connecting wind turbine blades to a hub of a nacelle of a wind turbine at an offshore target location, the method comprises the steps:

a) positioning an installation vessel at a wind turbine mast assembly at the target location,

the installation vessel or vessels comprising a lifting device configured for lifting wind turbine components, the wind turbine mast assembly comprising:

o amast, co a nacelle support at an upper end of the mast, o a root end moving assembly defining a guide path which extends over a vertical distance, the root end moving assembly comprising a movable root end support base and a root end support configured for supporting and guiding the root end of the blade, the root end support being connected to the movable root end support base, the root end support being movable along the guide path, the root end support being configured for engaging the root end of the blade in an engagement position thereof, the root end moving assembly being configured for moving the root end of the blade upward along the guide path from the engagement position to an installation position of the blade,

b) positioning a nacelle comprising a hub on the mast,

c) engaging a blade with the root end support at the engagement position and moving the blade upwards towards the hub from the engagement position to the installation position in a joint operation of the root end moving assembly and the lifting device, wherein the root end is supported and guided by the root end support and the lifting device carries a majority of the vertical loads on the blade,

d) connecting the root end of the first blade to the hub,

e) repeating steps c) and d) for at least one subsequent blade, and in particular all blades, thereby forming either a complete rotor nacelle assembly (RNA) or a partial (RNA).

In yet a further, independent aspect, the invention relates to a method for connecting wind turbine blades to a hub of a nacelle of a wind turbine at an offshore location, the method comprises the steps: a) positioning an installation vessel at a wind turbine mast assembly at the target location, the installation vessel comprising a lifting device configured for lifting wind turbine components, wherein the installation vessel further comprises an auxiliary support structure connected to a hull or deck of the installation vessel, the auxiliary support structure comprising: o a positioning assembly, o aroot end moving assembly comprising a movable root end support base and a root end support configured for supporting and guiding the root end of the blade, the root end support being connected to the movable root end support base, the root end support being configured for engaging the root end of the blade in an engagement position thereof, the root end moving assembly being configured for moving the root end of the blade from the engagement position to an installation position of the blade, wherein the root end moving assembly is connected to the positioning assembly and the positioning assembly allows the movement of the root end moving assembly.

the wind turbine mast assembly comprising: o amast, co anacelle support at an upper end of the mast, b) positioning a nacelle comprising a hub on the mast, c) engaging a root end of the blade with the root end support at the engagement position and moving the blade towards the hub from the engagement position to the installation position in a joint operation of the auxiliary support structure and the lifting device, wherein the root end is supported and guided by the root end support and the lifting device carries a majority of the vertical loads on the blade, d) connecting the root end of the first blade to the hub, e) repeating steps c) and d) for at least one subsequent blade, and in particular all blades, thereby forming either a complete rotor nacelle assembly (RNA) or a partial (RNA).\ This embodiment can be particularly useful when the installation vessel is a non- floating device, in particular a jack-up rig. This embodiment can also be used on a floating vessel.

When used on a floating device, the floating device can be a semi-submersible vessel that comprises a dynamical position system in order to remain at substantially the same position. Alternatively, the floating vessel can be physically moored in order to remain at substantially the same position. The auxiliary support structure can then offer one or more degrees of freedom to uncouple the movement of the mast from the movement of the installation vessel. In this embodiment, the root end moving assembly may comprise a mast stop configured to engage the mast or the nacelle in the installation position and that can be uncoupled from the movement of the installation vessel together with the root end moving assembly. The installation position can be located outboard of the installation vessel.

The positioning assembly can comprise an elongated member, wherein the elongated member is connected to the hull or deck of the installation device via a hinge located at one extremity of the elongated member and wherein the root end moving assembly is connected to the opposite extremity of the elongated member.

The positioning assembly may extend at least partially upwards from the deck or hull of the installation vessel.

In the embodiment wherein the root end moving assembly comprises a mast stop, the mast stop may comprise a mast gripper configured to engage the mast and to connect the root end moving assembly to the mast, wherein the positioning assembly comprises at least of degree of freedom allowing the relative motion of the root end moving assembly and mast with respect to the installation vessel.

More specifically, the positioning assembly comprises three degrees of freedom.

The nacelle can be placed on the wind turbine mast which is already placed on its foundation. This can be a fixed foundation (jacket/monopole) or a floating foundation. A nacelle support forms the interface between nacelle and mast. The nacelle support is configured to support the nacelle during the operational life of the wind turbine.

In some embodiments, the guide path of the blade moving system comprises of a loading rail, having one end at the nacelle support, and having another end, further away from the nacelle support. The wind turbine mast assembly may have been pre-installed by the same installation vessel or by a different installation vessel. The installation of the wind turbine assembly may be a sub-procedure part of step a) and be carried out prior to step b). Along this loading rail, a movable root end support base may roll or slide between a pickup location and an installation position. Herein, a root end support is directly or indirectly mounted to the movable root end support base and is moved by the combination of the movable root end support base and a drive system. This drive system may be embodied by the use of winches. However, the skilled person will note that a variety of drive systems is possible.

This root end support may then engage the root end of a blade and may then move together with the movable root end support base, moving the root end of the blade along a guide path to the root end connector of the nacelle.

In order to minimise the load on the root end moving assembly, part of the blade is engaged by a lifting device, in particular near the centre of gravity of the blade, more in particular at the centre of the gravity. The crane lifts the blade in cooperation with the root end moving assembly. If the blade is engaged near the centre of gravity, the root end moving assembly carries a small portion of the weight of the blade. If the blade is engaged in the centre of gravity, the root end moving assembly only guides the root end of the blade. The pickup orientation of the blade may vary, however, it is preferable that the blade be in harizontal orientation.

In one embodiment, the joint operation of the lifting device and upward movement of the root end moving assembly leads to the maintaining of the horizontal orientation of the blade during the blade movement from an engagement position to an installation position.

To reduce loads on the blade due to a potential mismatch in velocity or position of the crane and root end moving assembly, in one embodiment, the rotation around the Y and Z direction is fully released between the root end support and the movable root end support base.

In another embodiment, the rotation around the Y and Z direction is partially released in the connection between the root end support and the movable root end support base to reduce loads on the blade. The partial release may be done by using actuators or springs or any other obvious device. Using this freedom in rotation, when the root end support has been moved into position, the crane may be used to pivot the blade around the Y and Z direction. By doing so, the plane of root end of the blade may be aligned with the plane of the root end connector of the hub of the nacelle. The connection between the movable root end support base and the root end support may comprise actuators, the final alignment and positioning of the root end of the blade may use these actuators. These actuators may translate the blade in X, Y, and Z direction or rotate the blade about any of these directions. This is particularly useful for the alignment of the multiple threaded ends of the blade root end to the holes of the root end connector.

To oversee and control the assembly process during the lifting of the blade and during the installation process, the loads on the blade are monitored by use of sensors. In addition, the orientation of the blade with respect to a fixed coordinate system is also monitored by use of sensors.

The operator of the lifting device also operates the auxiliary support structure or the root end moving assembly. Herein, the operator can be provided with means to monitor the orientation of the blade with respect to a fixed coordinate system and to monitor the loads on the blade moving system as a result of the orientation of the blade.

The lifting device and the auxiliary support structure or the root end moving assembly can be coupled via a control unit and the control unit can be used to move the lifting device and the root end moving assembly in tandem, wherein input data for the control unit comprises the vertical position of both the root end moving assembly and the connection point of the lifting device to the blade and wherein said input data is used to calculate relative locations and/or speeds of the connection point of the lifting device to the blade and of the root end support.

In yet another independent aspect, the invention relates to a method for disconnecting wind turbine blades from a hub of a nacelle of a wind turbine at or near an offshore location is also provided, wherein the wind turbine comprises a mast and a nacelle support at the upper end of the mast, the method comprising the steps: a) positioning an installation vessel at the target location, the installation vessel comprising a lifting device configured for lifting wind turbine components, and b) positioning a root end moving assembly on the mast, the root end moving assembly defining a guide path which extends over a vertical distance, the root end moving assembly comprising a movable root end support base and a root end support for supporting a root end of the blade, the root end support being connected to the movable root end support base, the movable root end support being moveable over a vertical distance, c) supporting a blade jointly with the root end moving assembly and the lifting device at a de-installation position of the blade, and d) disconnecting the root end of a first blade from the hub, and e) supporting and/or guiding the blade jointly with the root end moving assembly and the lifting device and moving the blade downwards towards a disengagement position in a joint operation of the root end moving assembly and the lifting device, wherein the root end is supported by the root end support of the root end moving assembly and the lifting device carries the majority of the vertical loads on the blade, and f) disengaging the root end from the root end support and removing the blade from the root end moving assembly, and g) repeating the steps c) to f) for at least one subsequent blade.

In an even further, independent aspect, the invention relates to a method for disconnecting blades from a hub of a nacelle of a wind turbine at or near an offshore location, wherein the wind turbine comprises a mast and a nacelle support at the upper end of the mast, the method comprises the steps: a) positioning an installation vessel according to claim 3 at the target location, the installation vessel comprising a lifting device configured for lifting wind turbine components, and b) positioning the root end moving assembly at a de-installation position of the blade, c) supporting a blade jointly with the auxiliary support structure and the lifting device at the de-installation position of the blade, and d) disconnecting the root end of a first blade from the hub, and e) supporting and/or guiding the blade jointly with the auxiliary support structure and the lifting device and moving the blade downwards towards a disengagement position in a joint operation of the auxiliary support a structure and the lifting device, wherein the root end is supported by the root end support of the root end moving assembly and the lifting device carries the majority of the vertical loads on the blade, and f) disengaging the root end from the root end support and removing the blade from the root end moving assembly, and g) repeating the steps c) to f) for at least one subsequent blade.

The blade moving system is positioned near the side of the installation vessel to minimise lift time and lift distance when a blade or nacelle is being transferred.

The present invention further relates to a blade positioning system configured for positioning wind turbine blades at a hub of a nacelle of a wind turbine from an installation vessel at an offshore target location, wherein the blade positioning system comprises: the installation vessel comprising: — atleast one lifting device configured for lifting wind turbine components, and — an auxiliary support tower extending upwardly from a hull or deck of the installation vessel, the auxiliary support tower comprising: o a nacelle support for supporting the nacelle, o aroot end moving assembly defining a guide path which extends over a vertical distance, the root end moving assembly comprising a movable root end support base and a root end support configured for supporting and guiding the root end of the blade, the root end support being connected to the movable root end support base, the root end support being movable along the guide path, the root end support being configured for engaging the root end of the blade in an engagement position thereof, the root end moving assembly being configured for moving the root end of the blade upward along the guide path from the engagement position to an installation position of the blade, wherein at least one lifting device is configured for lifting the nacelle onto the auxiliary support tower, wherein at least one lifting device and the root end moving assembly are configured to jointly support a blade and jointly move the blade upwards towards the hub, wherein during the upward movement the root end is supported by the root end support of the root end moving assembly and the lifting device carries a majority of the vertical loads on the blade.

The present invention further relates to a blade positioning system configured for positioning wind turbine blades at a hub of a nacelle of a wind turbine from an installation vessel at an offshore target location, wherein the blade positioning system comprises: — the installation vessel comprising at least one lifting device configured for lifting wind turbine components, and

— awind turbine mast assembly positioned at the target location adjacent the installation vessel, the wind turbine mast assembly comprising: — amast, — a nacelle support located at an upper end of the mast and — a root end moving assembly connected to the mast and defining a guide path which extends over a vertical distance, the root end moving assembly comprising a movable root end support base and a root end support configured for supporting and guiding the root end of the blade, the root end support being connected to the movable root end support base, the root end support being movable along the guide path, the root end support being configured for engaging the root end of the blade in an engagement position thereof, the root end moving assembly being configured for moving the root end of the blade upward along the guide path from the engagement position to an installation position of the blade, wherein the at least one lifting device is configured for lifting the nacelle onto the wind turbine mast, wherein the at least one lifting device and the root end moving assembly are configured to jointly support a blade and jointly move the blade upwards towards the hub, wherein during the upward movement the root end is supported by the root end support of the root end moving assembly and the lifting device carries a majority of the vertical loads on the blade.

The present invention also relates to a blade positioning system configured for positioning wind turbine blades at a hub of a nacelle of a wind turbine from an installation vessel at an offshore target location, wherein said wind turbine comprises: — a wind turbine mast assembly comprising: * a mast, e a nacelle support at an upper end of the mast, and wherein the blade positioning system comprises: — the installation vessel comprising: ¢ at least one lifting device configured for lifting wind turbine components, and e an auxiliary support structure comprising o a positioning assembly, o a root end moving assembly comprising a movable root end support base and a root end support configured for supporting and guiding the root end of the blade, the root end support being connected to the movable root end support base, the root end support being configured for engaging the root end of the blade in an engagement position thereof, the root end moving assembly being configured for moving the root end of the blade from the engagement position to an installation position of the blade, wherein the at least one lifting device is configured for lifting the nacelle onto the wind turbine mast, and wherein the at least one lifting device and the root end moving assembly are configured to jointly support a blade and jointly move the blade upwards towards the hub, wherein during the upward movement the root end is supported by the root end support of the root end moving assembly and the lifting device carries a majority of the vertical loads on the blade.

In one embodiment, the installation device comprises a loading rail and a movable root end support base that moves along the loading rail. This loading rail is connected to the nacelle support structure having a one end at the nacelle support, and another end further away from the nacelle support. This loading rail defines a guide path along which the movable root end support base moves. This loading rail extends over a vertical distance and may be exactly vertical.

In the engagement position of the root end support, the root end support may engage a root end of a blade which is in a horizontal or substantially harizontal position.

The root end support is connected to the movable root end support base in a manner so that the blade may rotate with respect to the movable root end support base. This rotation may be free in one embodiment, while in another embodiment it is partially braked and/or dampened.

In one embodiment, the connection between the root end support and the root end support base may not only rotate, but may also be actuated to move the root end (and the blade) in all six degrees of freedom.

In order to reduce the complexity and improve the safety of the instalment of the blades to the nacelle, several sensors may be present. In one embodiment, the installation device is equipped with sensors to measure the load on the blade. In another embodiment, the installation device is equipped with sensors to observe the orientation of the blade relative to a fixed coordinate system.

The present invention further relates to a root end moving assembly according to claim 69 and to a wind turbine mast assembly according to claim 71.

Further advantageous features are defined in the dependent claims.

These and other aspects of the invention will be more readily appreciated as the same becomes better understood by reference to the following detailed description and considered in connection with the accompanying drawings in which like reference symbols designate like parts.

BRIEF DESCRIPTION OF THE FIGURES Figures 1A and 1B depict the top view of two embodiments of the invention on two different ships.

Figures 2A-2C depict the process of transporting a blade between an engagement and an installation position along an auxiliary tower.

Figures 3A, 3B depict a root end supported by a blade positioning system at an engagement position.

Figures 4A, 4B depict a root end supported by a blade loader rotated around the vertical axis and towards the nacelle.

Figures 5A, 5B depict a root end supported by a blade loader rotated around the vertical axis and away from the nacelle.

Figures 6A, 6B depict a root end supported by a blade loader rotated around a horizontal axis with the crane block at a higher position than the root end support.

Figures 7A, 7B depict a root end supported by a blade loader rotated around a horizontal axis with the crane block at a lower position than the root end support.

Figures 8A-8C depict a blade engaging a root end support.

Figures 9A-9C depicts a root end supported by a blade loader at the installation position. The blade is shown in an extreme position furthest away from the nacelle, in a central position, and in an extreme position closest to the nacelle.

Figures 10A-10C depicts a root end supported by a blade loader at the installation position. The blade is shown at various positions along the X-direction along the longitudinal direction of the blade, during the installation process.

Figures 11A, 11B depict a further embodiment of the invention.

Figures 12A, 12B, 12C depict three top views of the nacelle, root end support, and blade.

Figures 13A, 13B depict two embodiments of the blade positioning system. Figure 13A shows an embodiment wherein the movable root end support base is not able to move along the guide path, and Figures 13B shows an embodiment comprising a guide path that does not extend along the full length of the mast of tower.

Figures 14A-C depict another embodiment of the invention comprising an auxiliary support structure at an engagement position, and intermediate position and an installation position.

Figures 15A and 15B depict a further embodiment of the invention comprising an auxiliary support structure.

Figures 16A-C depict an embodiment wherein the mast stop engages the mast.

Figures 17A-C depict another embodiment of the auxiliary support structure being moved between an engagement position and an installation position.

Figures 18A and 18B depict the top of the auxiliary support structure wherein the blade is in the installation position. The root end of the blade is moved to be connected to the hub.

Figures 19A-19C depict a root end supported by a blade loader at the installation position. The blade is shown in an extreme position furthest away from the nacelle, in a position closer to the nacelle, and in an extreme position closest to the nacelle.

Figures 20A-20C depict a root end of a blade being supported by a blade loader. The blade being rotated counter clockwise with respect to an aligned position, being rotated clockwise with respect to an aligned position and being in an aligned position.

Figures 21A-21E depict an installation of a blade. The root end of the blade is shown between a remote position and a connected position.

Figures 22A-22C depict the root end of a blade being supported by a blade loader in a position relatively far away from a hub, in a position closer to a hub and in a position connected toahub.

Figures 23A-23C depict a root end supported by a blade positioning system rotated around the vertical axis towards the nacelle, in a neutral position, and away from the nacelle.

Figure 24A-24C depict a root end supported by a blade positioning system being moved in a vertical direction.

Figures 25A-25C depict a root end supported by a blade loader at the installation position. The blade is shown in an extreme position furthest away from the nacelle, in a central position, and in an extreme position closest to the nacelle.

Figures 26A-26B depict two top views of the blade positioning system and shows the increased clearance when engaging the root end of the blade at the engagement position instead of the installation position.

Figures 27A-27B depict two embodiments for which a blade is loaded and attached to a hub under an angle.

Figures 28A-28C depicts the process of moving a blade in the direction orthogonal to the X- and Y-direction.

DETAILED DESCRIPTION OF THE FIGURES Turning to figures 1A , 1B, and 1C three embodiments of the blade positioning system comprising an installation vessels 10A, 10B, 10C positioned at an offshore target location are shown. The embodiment of figure 1C represents a separate invention that is closely related to the two embodiments in figures 1A and 1B. On the decks 12A, 12B, 12C of the installation vessels lifting devices 14A, 14B, 14C are shown. In these embodiments, the lifting device is a crane. This lifting device is configured to lift wind turbine components. With reference to figures 1A and 2A-2C, an auxiliary support tower 20 extends upwardly from a deck 12A of the installation vessel 10A. The auxiliary support tower also may be connected to the hull, for instance on the side thereof, and rise upwardly from the hull. The auxiliary support tower comprises a nacelle support 22A for supporting the nacelle. A root end moving assembly 30 is provided comprising a movable root end support base 32 and a root end support 34 which is configured for supporting and guiding the root end of the blade. The root end support is connected to the movable root end support base.

A guide path 24 is located adjacent the auxiliary support tower. The root end support 34 and the root end support base 32 are movable along the guide path, in this embodiment, the guide path comprises a rail. The guide path extends over a vertical distance. The guide path may be vertical. The root end moving assembly 30 is configured for moving the root end of the blade upward along the guide path from and engagement position 242 to an installation position 241 of the blade. The installation position is at the nacelle support 22A. The engagement position 242 is located at a distance below the installation position. The root end moving assembly 30 is connected to the auxiliary support tower. The root end moving assembly comprises a movable root end support base 32 and a root end support 34. The root end support is equipped for supporting a root end 52 of the blade

50. Herein, the root end support is connected to the movable root end support base. The root end support 34 is moveable along the guide path 24 between the engagement position 242 and the installation position 241.

In the second embodiment, depicted in figures 1B and 13B, a wind turbine mast assembly 40 has been installed at an offshore location and comprises a mast 42, a nacelle support 22B at an upper end of the mast, and a guide path 24 extending over a vertical distance. the guide path being defined between an installation position 241 at the nacelle support and an engagement position 242 which is located below the installation position. The second embodiment is similar to the first embodiment in many ways, but instead of the auxiliary support tower the mast 42 of the actual wind turbine is used. This is a more direct method.

In the separate, but related invention depicted in figure 1C, a wind turbine mast assembly 40 has been installed at an offshore location and comprises a mast 42 and a nacelle support at an upper end of the mast. The installation vessel 12C is shown comprising an auxiliary support structure 70 which comprises a positioning assembly 72 and a root end moving assembly.30 The root end moving assembly 30 is provided comprising a movable root end support base and a root end support which is configured for supporting and guiding the root end of the blade. The root end support is connected to the movable root end support base.

In the invention depicted in figure 1C, the installation vessel 12C is shown to be a jack- up rig. For this embodiment, while also applicable for a floating vessel, a jack-up rig is a preferred installation vessel.

Returning to figures 2A, 2B and 2C, the method for connecting a wind turbine blade to a hub 44 of a nacelle 46 of a wind turbine is shown. The auxiliary support tower 20 extends upwardly from a deck 12 of the installation vessel 10. The nacelle with a hub has been placed on the auxiliary tower. Two blades 50B, 50C have already been connected to the hub. The hub 44 has been oriented for a root end connector 441 to be available to engage the root end 52 of a blade 50A.

In figure 2A, a blade 50A is supported by a lifting frame 16 connected to a lifting device 14A or 14B (not shown in these figures) via one or more cables. The root end 52 of the blade is supported by the root end moving assembly 30. The lifting device is connected close to, and more in particular at, the centre of gravity of the blade. The root end support 34 is positioned at a distance below the installation position 241. The root end support is in particular positioned at the engagement position 242. The root end support base 32 is connected to a guide path

24.

In figure 2B, through the joint operation of the root end moving assembly 30 and lifting device, the blade 50 has been moved upwardly away from an engagement position 242 to an intermediate position 243. The intermediate position lies in between the engagement position 242 and the installation position 241.

In figure 2C, the root end support 34 is at an installation position 241. Here, the root end 52 of the blade is positioned in the vicinity of the root end connector 441 of the hub 44. At this location, the blade may be connected to the hub, thus forming (part of} a rotor nacelle assembly. Obviously, the skilled person will understand that the general principle described above and depicted in figures 2A-2C may also be applicable for a guide path extending along an installed wind turbine mast as shown in figure 13B for the second embodiment. Also, in the embodiment shown in figure 2A-2C, the blade may be oriented horizontally during every step of the process. It may be understood that the angle between the blade and the horizon may also be larger or smaller than zero degrees.

Turning to figures 3A and 3B, the root end support 34 is shown at a lower end of the guide path 24. The movable root end support base 32 of the root end moving assembly 30 is shown and is connected to the guide path 24. The root end support is connected to the movable root end support base extending outwardly from the guide path. The root end 52 of the blade is supported by the root end support 34. In this embodiment, the lifting device 14 is connected to the blade via a lifting frame 16. Figure 3A shows the root end moving assembly at the base 26 of the auxiliary tower 20. Figure 3B shows the root end moving assembly at the lower position of the guide path 24 in an embodiment where the guide path doesn’t extend over the entire length of the auxiliary tower or over the entire length of a turbine mast.

Turning to figures 4A and 4B, similar situations to figure 3 are shown. In figure 4, the blade is rotated counter-clockwise with respect to the vertical. Figure 4A shows this rotation with respect to the situation in figure 3A at the lower end of the guide path. Figure 4B shows this rotation with respect to the situation in figure 3B at the upper end of a guide path. It can easily be understood that this rotation is also possible at any intermediate position 243 between the engagement position 242 and the installation position 241.

Turning to figures 5A and 5B, similar situations to figure 3 are shown. In figure 5, the blade is rotated clockwise with respect to the vertical. Figure 5A shows this rotation with respect to the situation in figure 3A at the lower end of the guide path. Figure 5B shows this rotation with respect to the situation in figure 3B at the upper end of a guide path. It can easily be understood that this rotation is also possible at any intermediate position between the engagement position 242 and the installation position 241.

The rotation of the blade around the Z-axis is allowed through the pivotal connection of the root end support 34 to the movable root end support base 32. In one embodiment, at the installation position 241 of the root end moving assembly 30, the pivot point 38 (as shown in figure 6) around which the root end support pivots, lies in the plane of the root end connector 441 of the hub 44 and coincides with the X-axis 1, which coincides with the longitudinal axis of the blade 50. The X-axis does not intersect a vertical mast/tower axis 421 of the auxiliary support tower or mast but instead extends at a horizontal distance from the vertical mast/tower axis which horizontal distance corresponds to a hub projection distance over which the hub projects forward from the vertical mast/tower axis when the nacelle is positioned on the nacelle support. In doing so the movement relative to the root end connector remains as small as possible. Turning to figures 6A-6B, similar situations to figure 3 are shown. In figure 6, the blade is rotated upwards with respect to the Y-axis 2. The Y-axis is defined by being orthogonal to the longitudinal direction 1 of the blade 50 and by being in the horizontal plane. Figure 8A shows this rotation with respect to the situation in figure 3A at the lower end of the guide path. Figure 6B shows this rotation with respect to the situation in figure 3B at the upper end of a guide path. It can easily be understood that this rotation is also possible at any intermediate position between the engagement position 242 and the installation position 241.

Turning to figures 7A-7B, similar situations to figure 3 are shown. In figure 7, the blade is rotated downwards with respect to the Y-axis 2. The Y-axis is defined by being orthogonal to the longitudinal direction 1 of the blade 50 and by being in the horizontal plane. Figure 7A shows this rotation with respect to the situation in figure 3A at the lower end of the guide path. Figure 7B shows this rotation with respect to the situation in figure 3B at the upper end of a guide path. It can easily be understood that this rotation is also possible at any intermediate position between the engagement position 242 and the installation position 241. The rotation of the blade around the Y-axis is allowed by the connection of the root end support 34 via a support base 36 to the movable root end support base 32. In one embodiment, this connection is realised by pivotally connecting through a hinge a separate support member to the root end support. In one embodiment, the rotation of the blade around the Z-axis is allowed through the pivotal connection of the intermediate frame 36 to the movable root end support base 32 In one embodiment, at the installation position 241 of the root end moving assembly, the pivot point

38 around which the root end support pivots, lies in the plane of the root end connector 441 of the hub 44 and coincides with the longitudinal axis 1 of the blade 50. In one embodiment, the rotation about the Y-axis 2 and the vertical Z-axis is free and unhindered. In another embodiment, the rotation about the Y-axis 2 and the vertical Z-axis may be braked or dampened. This freedom in rotation may be used to compensate for a potential mismatch in displacement of the connection of the lifting device to the blade with respect to the root end moving assembly.

In one embodiment, the rotation about the Y-axis 2 and the vertical Z-axis is realised by the movement of the blade 50 by the lifting device 14 with respect to the root end moving assembly 30. This can be achieved by moving the connection of the lifting device to the blade up and down to rotate the blade over the Y-axis 2. To achieve the rotation about the vertical Z- axis, the connection of the lifting device to the blade may be moved in a direction parallel to the Y-axis 2.

In one embodiment, this rotation around the Y-axis and the Z-axis may be used to align the root end 52 of the blade 50 with the root end connector 441 of the hub 44 during the aligning and connecting of the blade to the hub when the root end moving assembly 30 is in the installation position 241.

In figures 3A, 4A, 5A, 6A, and 7A, the auxiliary tower 20 is shown with the guide path 24 being embodied by a rail. In the middle of this rail, a possible embodiment of a drive system is shown. Here, the drive system comprises a rack 28 that may extend over the entire length of the guide path 24. In this embodiment, a pinion 321 connected to the root end moving assembly engages the rack 28 and permits the root end moving assembly 30 to move along the guide path 24.

It will be understood that this rack 28 and pinion 321 may be used to align the root end 30 52 of the blade 50 with the root end connector 441 of the hub 44 in the Z-direction.

Turning to figures 8A-8C, the process of engaging the root end 52 of the blade 50 and the root end support 34 is depicted at the engagement position. In figure 8A, the projections 341A, 341B are in the open position ready to receive the root end 52 of the blade 50. Moving to figure 8B, the root end 52 of the blade has been positioned on (or in) the root end support 34 and is still supported by the lifting device 14 through the lifting frame 16. Moving to figure 8C, the projections 341A, 341B have been closed and grip the root end 52 of the blade 50.

Turning to figures 9A-9C, the root end moving assembly 30 is depicted at the installation position 241. In this embodiment, the intermediate frame 36 is moveably connected to the movable root end support base 32. In figure 9A, an actuator 361 has moved the intermediate frame 36 towards the nacelle 46 along the Y-direction. Figure 9B depicts the middle position of the root end support. Figure 9C shows the situation where an actuator 361 has moved the root end support away from the nacelle along the Y-direction. The movement of the root end support with respect to the movable root end support base may be used to align the root end 52 of the blade 50 with the root end connector 441 of the hub 44 along the Y-direction. Turning to figures 10A-10C, the root end moving assembly 30 is depicted at the installation position 241. In this embodiment, the intermediate frame 36 is moveably connected to the movable root end support base 32. In figure 10A, the intermediate frame 36 is located furthest away from the hub 44 of the nacelle 46 as possible. Figure 10B shows the root end support having been moved away from the position in figure 10A towards the hub of the nacelle. Figure 10C shows the root end support being moved towards the hub of the nacelle even further. In the position of figure 10C, the root end of the blade and the root end connector have been aligned and may be connected. Turning to figures 11A and 11B root end moving assembly is shown together with the personnel support platform 23. In figure 11A, the root end moving assembly 30 is shown at the installation position 241. In this representation, the root end 52 has been aligned and connected to the root end connector 441 of the hub 44. At a lower elevation than the installation position 241, a personnel support platform 23 is shown. This personnel support platform 23, providing access to the root end moving assembly, is used by people to assist the blade positioning system and it is used for maintenance purposes.

In figure 11B, the root end moving assembly is shown positioned at the lower end of the guide path 24. The blade 50 has been engaged by the root end support 34. A personnel support platform 23 provides access to the root end moving assembly and is used to assist the blade positioning system and for maintenance purposes.

Turning to figures 12A-12C, a top view of the nacelle 46, the hub 44, the blade 50, and the root end moving assembly 30 is shown in three different ways. In figure 12A, a top view is shown of the movable root end support base 32 and the intermediate frame 38, which are left out in figure 12B and 12C.

In figure 12C, various axes and planes are depicted; the longitudinal axis 461 of the nacelle, the centre axis 245 of the guide path, the plane of the root end 52 of the blade 50, the plane 442 of the root end connector 441 of the hub 44.

In figure 13A, a different embodiment is shown of the blade positioning system wherein the movable root end support base is not moveable along a guide path. In other words, the installation position 241 and the engagement position 242 coincide. Further, figure 13B shows a mast of a wind turbine instead of an auxiliary support tower and relates to a further embodiment of the method in which the connecting of the blades to the hub takes place when the nacelle including the hub are already placed on the mast.

In figures 14A-14C, an embodiment of the invention is shown wherein the installation vessel is a jack-up rig with jack-up legs 15 (as shown in Fig. 1C) and comprises an auxiliary support structure 70. In figure 14A, the auxiliary support structure 70 is shown with the root end moving assembly 30 in the engagement position 242. The nacelle 46 with a hub 44 has been placed on the turbine mast 42. Two blades have already been connected to the hub. The hub 44 has been oriented for a root end connector to be available to engage the root end of a blade

50.

In figure 14A, a blade 50 is supported by a lifting frame 16 connected to a lifting device 14 via one or more cables. The root end 52 of the blade is supported by the root end moving assembly 30. The blade 50 has been connected to the root end moving assembly 30 in the engagement position 242.

From a stored position on deck (not shown in this figure) the long blade 50 is lifted by the lifting device 14 which is connected close to, and more in particular at, the centre of gravity of the blade 50. The blade 50 is carefully lifted upwards and positioned above the root end moving assembly before engaging it in the root end moving assembly 30. This process may be quite challenging because wind may act on the movement of the blade. In figures 21A-21E, the engagement of a blade 50 by the root end moving assembly 30 is further depicted in detail.

The majority of the vertical loads on the blade 50 are carried by the lifting device 14 through the lifting frame 16. The auxiliary support structure 70 comprises a positioning assembly 72 that is connected to the deck of the installation vessel at one extremity.

The positioning assembly 72 comprises an elongated member 76A which can pivot about a rotation axis 78A via a hinge 79A. The root end moving assembly is located at the upper extremity of the elongated member 768A. In figure 14B, the positioning assembly 72 has pivoted around an axis 78A via a hinge 79A located at the lower extremity that is connected to the deck and by actuators 75 that are also connected to the deck. In doing so, the root end moving assembly 30 has been positioned closer to the hub 44 that is connected to the nacelle 486, which is supported by the mast 42. In figure 14C, the positioning assembly 72 has been pivoted even further so that the mast stop 74 engages the mast 42. Turning to figures 15A-15B, the positioning assembly 72 is shown with a mast stop 74 comprising a mast gripper 741 comprising two projections that may act as a jaw. These projections are used to grip the mast in order to couple the motion of the root end moving assembly 30 with the motion of the top of the mast where the nacelle 46 is located. Figure 15A depicts the engagement position of the root end moving assembly 30 and figure 15B shows the positioning assembly 72 being rotated towards the mast 42.

Turning to figures 18A-16C, the process of gripping the mast is shown. In figure 16A, the mast stop 74 has engaged the mast 42 through the rotation of the positioning assembly

72. The blade 50 is supported by the root end support 34 which is connected to the movable root end support base 32 through the intermediate frame 36. In figure 16B, the mast gripper 741 has closed as a result of the actuation of actuators 742a, 742b (742b is not shown in the figure) and grips the mast 42. In figure 16C, the mast gripper 741 grips the mast 42 and the positioning assembly 72 creates one degree of freedom in direction 9 which allows the relative motion of the mast 42 with the root end moving assembly 30 with respect to the installation vessel 10C (the installation vessel is not shown in figure 16) . In another embodiment, the positioning assembly may create multiple degrees of freedom in directions other than direction

9. An example of such a degree of freedom may be the rotation around a horizontal axis of the root end moving assembly with respect to the elongated members. Further details of possible degrees of freedom that are created by the positioning assembly are depicted in figures 29A- C and 30A-C.

In figures 17A-17C, another embodiment of the auxiliary support structure 70 is shown, wherein the positioning assembly 72 comprises an elongated member 76B extending upwardly from the deck of the installation vessel. On the upper extremity of the elongated member, the positioning assembly comprises a lateral element 77 relative to which the movable root end support base may move. The lateral element 77 cantilevers outwardly over a horizontal distance from the elongated member 76B. A mast stop 74 is located under the moveable root end support base 32. In figure 17B, the moveable root end support base 32 has been laterally moved towards the mast 42. In doing so, the mast stop 72 engages the mast. In figure 17C,

the same situation is shown as in figure 17B, wherein there is no mast stop located under the moveable root end support base 32. Turning to figures 18A-181B, the embodiment shown in figure 17A-B is shown after the movement of the movable root end support base has caused the mast stop 74 to engage the mast 42. The root end of the blade 52 is supported by the root end support 34 which is connected to the moveable root end connector 32 through the intermediate frame 36. In figure 18B, the intermediate frame 36 has moved with respect to the movable root end support base 32 after the alignment of the root end 52 of the blade 52 with the root end connector 441 of the hub 44. In this position, the blade 50 can be fastened to the hub 44 of the nacelle 46. By first engaging the mast 42 with the mast stop 74, the motion of the root end moving assembly 30 is coupled to the motion of the mast 42, and with that to the motion of the hub 44. Because the top of the mast may move relative to the installation vessel, it is more effective to physically connect the root end moving assembly’s movement to the mast rather than to try and control it with, for example, a feedback loop. Because the mast stop 74 couples the motion of the mast 42 to the motion of the root end moving assembly 30, the alignment of the root end 52 of the blade 50 can be achieved. Figures 19A-19C depict the same movement as is shown in figures 9A-C. Herein, seen in top view, the root end 52 of the blade is aligned in the Y-direction with the root end connector 441 of the hub 44. Turning to figures 20A-20C, the alignment of the root end 52 of the blade 50 with the root end connector 441 is shown in top view. In figure 20A, the blade 50 is shown in a position corresponding to the rotation direction about the vertical axis depicted in figure 4. In figure 20B, the blade has been rotated about the vertical axis in a clockwise direction corresponding to the rotation in figure 5. In figure 20C, the root end 52 has been aligned with the root end connector 441 wherein the rotation corresponds to the rotation in figure 3. The rotation that is depicted is controlled by the operator of the lifting device by moving the blade 50 using the lifting device

14. Figure 21A-21E shows the process of installing a blade 50 for the embodiment of figure

14. It will be understood that this process can also be applied to the embodiment of figures 18A-18B and, for both embodiments, in the installation position 241 and the engagement position 242. In figure 21A, the mast gripper 741 has engaged the mast 42 and the projections 341A, 341B of the root end support 34 are in the open position ready to receive the root end

52 of the blade 50. The blade 50 is still relatively far away from the root end moving assembly

30. In figure 21B, the blade 50 has been positioned above the root end moving assembly 30 and is ready to be lowered to be engaged by the root end moving assembly 30.

Moving to figure 21C, the root end 52 of the blade has been positioned on (or in) the root end support 34 and is still supported by the lifting device 14 through the lifting frame 16. Moving to figure 21D, the projections 341A, 341B have been closed and grip the root end 52 of the blade 50. In figure 21E, the root end moving assembly 30 has been used to align and to connect the root end 52 of the blade 50 to the hub 44.

In figures 22A-22C, the root end moving assembly 30 is shown in top view. In figure 22A, the root end 52 of the blade 50 has been placed on the root end support 34, the root end support 34 being rotated away from the root end connector 441. This position increases the clearance between the root end 52 of the blade 50 and the root end connector in order to increase workability and reduce the chances of damaging the wind turbine components. Figure 22B depicts the blade 50 having been rotated from the position in figure 22A to the position in which the root end 52 of the blade 50 can be aligned with the root end connector 441. In figure 22C, the root end 52 of the blade 50 is connected to the root end connector 441.

In figures 23A-23C, a different embodiment is shown of the blade positioning system wherein the root end moving assembly 30 comprises a base frame 33. The base frame 33 has been lifted onto the mast 42 of the auxiliary support tower 20 prior to the attachment of the installation of the blades 50 with the lifting device 14. The root end moving assembly 30 further comprises the movable root end support base 35 that is directly connected to the base frame.

This connection allows the movable root end support base to rotate around the Z-axis, the Z- axis being offset over an offset distance from the root end support. The offset distance corresponds in particular substantially to the distance between the root end support and the root end connector of the hub, measured when the root end moving assembly supports the blade in the installation position. The control of this rotation is similar to that depicted in figures 3-5. The root end moving assembly also comprises a root end support 34 that is connected to the movable root end support base 35. In order to be able to align the root end 52 of the blade 50 with the root end connector 441, the root end moving assembly 30 comprises an actuator 362 that is able to move the root end support 34 upwards in the Z-direction.

In figure 23A the root end support 34 is rotated about the Z-axis away from the nacelle by the lateral movement of the lifting frame 16. In figure 23B, the root end support is in a neutral position. In figure 23C, the root end is rotated about the Z-axis towards the nacelle 46 by the lateral movement of the lifting frame 16. Similar to figures 6 and 7, rotation about the Y-axis may be achieved by the freedom of rotation in the root end support.

Turning to figures 24A-24C, the movement of the root end support along a guide path is depicted. In figure 24A, the root end support is at an engagement position 242. The engagement process of the blade and the root end support is similar to that depicted in figure

8. In figure 24B, the root end support has been moved along the guide path in the Z-direction through a joint operation of the actuator 362 of the root end moving assembly 30 and the lifting device 14. In figure 24C, the root end support has been moved even further along the guide path in the Z-direction until the longitudinal axis of the blade is collinear with the centre axis of the root end connector 441 of the hub 44.

Turning to figures 25A-25C, the movement of the root end support at the installation position is depicted. In figure 25A, the root end support has been positioned such that longitudinal axis of the blade is collinear with the centre axis of the root end connector 441 of the hub 44. In figure 25B, the root end of the blade has been moved along the X-axis towards the root end connector, wherein the X-axis is defined as the longitudinal axis of the blade. In figure 16C, the root end has been moved even further along the X-direction until the root end connector of the hub and the root end of the blade engage and can be connected. The movement along the X-direction can be achieved in several ways. An example of such a way is by the extension of an actuator that pushes the root end support 34 towards the root end connector 441. Another example is the use of a rack and pinion, wherein the movable root end support base 35 comprises a rack that can be engaged by a pinion driving the root end support 34 along the X-direction.

In figures 26A and 26B, the top views of figure 12B and 12C are shown depicting the increase in clearance when the root end of the blade would be engaged at a position lower than the installation position. For example, such an engagement may occur at 70% of the mast height of higher. In figure 26A, the root end 52 of a blade is shown while engaged in the engagement position. The distance 91 is the smallest distance along the longitudinal direction of the blade between the root end 52 of the blade and the closest object. In the engagement position, this object is the guide path 24 embodied by a rail. In figure 26B, a blade is shown while engaged in installation position. The distance 92 is the smallest distance along the longitudinal direction of the blade between the root end of the blade and the closest object. In the installation position, this object is the nacelle 46. It may be seen from figures 26A-B that the smallest distance 91 is larger than the smallest distance 92; figure 26A thus shows a larger clearance.

With respect to workability, the clearance of the root end of the blade is an important factor. By engaging the blade away from the installation position, the clearance increases. Additionally, the use of the engagement position is beneficial since a potential collision would only damage the blade and the guide path, instead of the blade and the nacelle when engaging the blade at the installation position.

In figures 27A and 27B, two different embodiments are shown. Figure 27A shows an embodiment of the invention at the top of an auxiliary support tower 20, and figure 27B shows the same embodiment at the top of a turbine mast 42. Both figures depict an embodiment wherein the moveable root end support 34 is connected under an angle to the guide path via the moveable root end support base 32. The blade 50 is oriented under the same angle.

By connecting the blade under an angle, the connecting point of the blade lifting arrangement is brought down. In doing so, the lifting device used to lift the blade may be significantly shorter than a lifting device lifting the blade in a horizontal orientation.

Turning to figures 28A, 28B, and 28C, the moveable root end support base is shown in the installation position 241 at the top of an auxiliary support tower 20. In this embodiment, the intermediate frame 36 is moveably connected to the movable root end support base 32. In figure 28A, the intermediate frame 36 is located furthest away from the hub 44 of the nacelle 46 as possible. Figure 28B shows the root end support having been moved away from the position in figure 28A towards the hub of the nacelle. Figure 28C show the root end support being moved towards the hub of the nacelle even further. In the position of figure 28C, the root end of the blade and the root end connector have been aligned and may be connected.

The connection between the intermediate frame 36 and the moveable root end support base 32 comprises at least an actuator configured to move the intermediate frame in the X- direction: the longitudinal direction of the blade. Additionally, it may also comprise an actuator which is configured to move the intermediate frame 38 in the horizontal Y-direction that is orthogonal to the X-direction. Also, it may comprise an actuator which is configured to move the intermediate frame 36 in the direction orthogonal to the X-direction and the Y-direction.

In the embodiment shown in figures 27A-B and 28A-C, the plane spanned by the X and Y direction is oriented under an angle with respect to the vertical, wherein the angle under which this plane is oriented is normal to the face of the root end connector of the hub.

In figures 29A-29C, the positioning assembly 70 of figure 15 is shown after the mast gripper 75 has engaged the mast 42. In the embodiment depicted in figures 29A-29C, the installation vessel is a floating vessel that either makes use of a dynamical positioning system or of a mooring system in order to remain at substantially the same position.

However, because none of either systems can eliminate all the movements of the installation vessel, the movement of the mast gripper, the root end moving assembly, and the mast 42 should be able to be uncoupled from the movement of the installation vessel. In figure 29B, the installation vessel is in the position where the mast gripper has just engaged the mast

42. The elongated member 72 is connected to the installation vessel at least via a hinge 79B. This hinge 79B permits the rotation around a vertical axis 78B of the positioning assembly 70.

The position of the installation vessel in this figure can be called the neutral position.

In figure 29A, while the vertical rotation axis 78B has not moved with respect to the mast 42, the installation vessel has rotated anti-clockwise around the axis 78B with respect to the neutral position. The positioning assembly 70 has also rotated around the axis 78B relative to the vessel via hinge 79B. In figure 29C, the vertical rotation axis 78B has still not moved with respect to the mast 42. The installation vessel has rotated clockwise around the vertical axis 78B relative to the neutral position. The positioning assembly 72 has rotated with respect to the installation vessel around the vertical axis 78B via hinge 79B. Because the positioning assembly 72 can create degrees of freedom by rotating with respect to the installation vessel, the movement of the mast gripper, the movement of the root end moving assembly and the mast can be uncoupled from the movement of the installation vessel.

Because the point of view in these figures is located on the installation vessel, it may seem that the mast 42 is moving relative to the installation vessel. However, this is not the case; the installation vessel moves with respect to the mast 42.

In figures 30A-30D, the same positioning assembly 70 and installation vessel are shown as in figure 29. Figure 30A depicts the situation wherein the mast stop 74 has just engaged the mast 42. Prior to the engagement of the mast 42 by the mast stop 74, the root end 52 of the blade 50 has been engaged with the root end moving assembly 30 in an engagement position and the elongated member has rotated about the horizontal axis 79A towards the installation position, bringing the root end 52 towards the root end connector 441.Figure 30B shows the same situation but from a top view. Herein, the root end 52 of the blade 50 is gripped by the projections 341A, 341B of the root end support 34 of the root end moving assembly 30 and is ready to be aligned with the root end connector 441 of the hub 44 of the nacelle 46. The elongated member 72 of the positioning assembly 70 has rotated around the horizontal axis 78A via hinge 79A to allow the mast stop 74 to engage the mast 42.

In figure 30D, the same situation as in figure 30C is shown in top view. In figure 30C, the installation vessel has remained in the same orientation with respect to the mast 42, but has translated away from the mast 42. To uncouple the movement of the installation vessel from the movement of the mast stop 74, root end moving assembly 30, and the mast 42, the positioning assembly creates degrees of freedom by combining its shortening and elongation with rotations and translations relative to the installation vessel. Adding to the degree of freedom in the direction 9, as is shown in figure 16C, the elongated member may also rotate around the horizontal axis 78A via hinge 79A after the mast stop 74 has engaged the mast 42.

In doing so, the installation vessel can translate away and towards the mast 42 while its movement does not affect the movement of the mast stop 74, root end moving assembly 30, and the mast 42.

The skilled person will understand that the degrees of freedom shown in figures 29 and 30 can be combined to uncouple the heave, sway, yaw, and roll of the installation vessel from the mast stop, root end moving assembly and mast. The surge and pitch of the installation vessel can also be uncoupled up to a certain range, for example from +10 to -10 degrees. For example, by adding a rotational degree of freedom around, for example, an axis orthogonal to the horizontal axis 79A and vertical axis 79B. In particular, this rotational degree of freedom can be located at the connection between the installation vessel and the positioning assembly and/or between the positioning assembly and the root end moving assembly.

The terms "a" or "an", as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising i.e., open language, not excluding other elements or steps.

Any reference signs in the claims should not be construed as limiting the scope of the claims or the invention. It will be recognized that a specific embodiment as claimed may not achieve all of the stated objects.

The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

White lines between text paragraphs in the text above indicate that the technical features presented in the paragraph may be considered independent from technical features discussed in a preceding paragraph or in a subsequent paragraph.

Claims

CONCLUSIONS

A method of connecting wind turbine blades (50) to a hub (44) of a nacelle (46) of a wind turbine at or near an offshore target site, the method comprising the steps of: a) positioning an installation vessel (12 ) at the target site, the installation vessel comprising a lifting device (14) adapted to lift wind turbine components, the installation vessel further comprising a support tower extending upwardly from a hull or deck of the installation vessel, the support tower comprising: o a nacelle support (20) for supporting the nacelle, o a base end movement system (30) defining a guideway extending a vertical distance, the base end movement system comprising a movable base end support base (32) and a base end support ( 34), arranged to support and guide the base end of the blade, the b shaft end support is connected to the movable base end support base, the base end support is movable along the guideway, the base end support is arranged to engage the base end of the blade in an engaged position thereof, the base end moving system is arranged to move upwards from the base end of the blade along the guideway from the engagement position to an installation position of the blade, b) positioning a nacelle (46) including a hub (44) on the support tower, c) engaging the blade with the base end support in the engagement position and raising the blade to the hub from the engagement position to the installation position in a joint operation of the base end moving system and the lifting device, the base end being supported and guided by the base end support and the lifting device a majority of the v bear ertical loads on the blade, d) connecting the base end of the first blade to the hub, e) repeating steps c) and d) for at least one subsequent blade, and in particular all blades, thereby either to form a complete rotor nacelle system (RNA) or a partial one (RNA).

A method of connecting wind turbine blades (50) to a hub (44) of a nacelle (46) of a wind turbine at an offshore target site, the method comprising the steps of: a) positioning an installation vessel (10) at a wind turbine tower system at the target site, the installation vessel or vessels comprising a lifting device (14) arranged for lifting wind turbine components, the wind turbine tower system comprising: o a mast (42), o a nacelle support at an upper end of the mast, o a base end movement system (30) defining a guideway extending a vertical distance, the base end movement system comprising a movable base end support base (32) and a base end support (34) arranged to support and guiding the base end of the blade, wherein the base end support is connected to the movable base end unbase, the base end support is movable along the guideway, the base end support is arranged to engage the base end of the blade in an engaged position thereof, the base end movement system is arranged to move the base end of the blade up along the guideway from the engagement position to an installation position of the blade, b) positioning a nacelle (46) including a hub (44) on the mast, c) engaging a blade with the base end support in the engaged position and raising moving the blade to the hub from the engagement position to the installation position in a joint operation of the base end moving system and the lifting device, the base end being supported and guided by the base end support and the lifting device carrying a majority of the vertical loads on the blade, d) connecting the base end of the ee first blade with the hub, e) repeating steps c) and d) for at least one subsequent blade, and in particular all blades, thereby forming either a complete rotor nacelle system (RNA) or a partial (RNA) .

A method of connecting wind turbine blades (50) to a hub (44) of a nacelle (46) of a wind turbine at an offshore target site, the method comprising the steps of:

a) positioning an installation vessel (10) at a wind turbine tower system at the target location, the installation vessel comprising a lifting device (14) adapted to lift wind turbine components, the installation vessel further comprising a support structure (70) connected to a deck or hull of the installation vessel, the support structure comprising: o a positioning system (72), o a base end movement system (30), comprising a movable base end support base (32) and a base end support (34) arranged to support and guiding the base end of the blade, the base end support being connected to the movable base end support base, the base end support is arranged to engage the base end of the blade in an engaged position thereof, the base end moving system is adapted to move the base end of the blade from the engagement position to an installation position of the blade, wherein the base end movement system is connected to the positioning system, in particular at a top thereof, and the positioning system allows the movement of the base end movement system, the wind turbine tower system comprising: o a mast (42), o a nacelle support on an upper end of the mast, b) positioning a nacelle (46) comprising a hub (44) on the mast, Cc) engaging a blade with the base end support in the engaged position and raising the the blade to the hub from the engagement position to the installation position in a joint operation of the base end moving system and the lifting device, wherein the base end is supported and guided by the base end support and the lifting device carries a majority of the vertical loads on the blade, d) connecting the base end of the first sheet m With the hub, €) repeating steps c) and d) for at least one subsequent blade, and in particular all blades, thereby forming either a complete rotor nacelle system (RNA) or a partial one (RNA).

A method according to the preceding claim, wherein the base end movement system comprises a mast stop (74) adapted to engage the mast or nacelle in the installation position and the movement of the mast stop and the base end movement system is disengaged from the movement of the installation vessel, in particular to follow the movement of the mast.

The method of any of claims 3-4, wherein the installation position is located outboard of the installation vehicle.

The method of any one of claims 3-5, wherein the positioning system comprises an elongate body, the elongate body being connected to the hull or deck of the installation vessel via a hinge located at one end of the elongate body and the base end movement system is connected to the opposite end of the elongate body.

The method of any of claims 3-6, wherein the positioning system extends at least partially upward from the deck or hull of the installation vessel.

The method of any of claims 3-7, wherein the mast stop comprises a mast gripper (741) adapted to engage the mast and connect the base end movement system to the mast, the positioning system having at least one degree of freedom creates to allow the relative movement of the base end movement system with respect to the installation vessel.

The method of any one of claims 3-8, wherein the positioning system creates three degrees of freedom in translation for the base end movement system relative to the elongate body when the mast stop is engaged on the mast.

A method according to any one of the preceding claims, wherein the movable base end support base comprises wheels or sliding elements, wherein during step c) the movable base end support base rolls or slides.

A method according to any preceding claim, wherein the base end support (34) is movably connected to the movable base end support base, thereby allowing rotation of the blade relative to the movable base end support base about the Z axis and/or Y-axis, where the Z-axis is vertical and the Y-axis is horizontal and perpendicular to an X-axis corresponding to a longitudinal axis of the blade, when the blade is in the installation position, wherein during the upward movement the blade rotates about the Z axis and/or Y axis due to a relative movement between the base end movement system and a lifting position where the lifting device supports the blade.

A method according to any one of the preceding claims except claim 11, wherein the base end movement system comprises: o a base frame (33), o the movable base end support base (35) connected to the base frame and movable, in particular rotatable, relative to the base frame, the base end support (34) connected to the movable base end support base (35), the base end support being movable relative to the movable base end support base.

The method of claim 12, wherein the base end support (34) is movably connected to the movable base end support base (35), thereby allowing rotation of the blade and the base end support (34) relative to the movable base end support base (35). support base about the Y axis, the Y axis being horizontal and perpendicular to an X axis corresponding to a longitudinal axis of the blade when the blade is in an installation position, and the movable base end support base is rotatable connected to the base frame about the Z axis, the Z axis being vertical, during the upward movement the blade rotates about the Z axis and/or Y axis due to a relative movement between the base end support and a lifting position where the lifting device supports the blade.

The method of any preceding claim, wherein the base end motion system comprises one or more brakes or dampers to limit or dampen the rotation of the base end support about the Y axis and the Z axis, more in the particularly, the one or more brakes or dampers only limit or dampen the rotation of the base end support about the Y axis and the Z axis in or near the blade installation position, more preferably while connecting the base end of the blade blade with a hub base end connector.

A method according to any one of the preceding claims 11-14, wherein the Z-axis is offset by an offset distance from the base end support,

wherein the offset distance corresponds substantially to the distance between the base end support and the base end connector of the hub, measured when the base end is supported by the base end support in the installation position.

A method according to any preceding claim, wherein in step c) the base end of the blade engages the base end support in the engaged position, while the lifting device carries a majority of the weight of the blade.

A method according to any one of the preceding claims except claims 3-9, wherein the guideway comprises at least one rail connected to the support tower or the mast, in particular fixed thereto, the rail having a first, lower end and has a second, upper end, the upper end being at the nacelle support and the lower end being below the upper end, wherein in step c) the movable base end support base moves up along the rail, thereby raising the base end .

The method of any preceding claim, wherein the base tip movement system carries the majority of horizontal loads acting on the blade in the longitudinal direction of the blade (forces in the X direction), and wherein the forces on the blade in a horizontal Y direction, which is perpendicular to the longitudinal direction of the blade, are carried by a combination of the crane, one or more pulllines extending from the installation vessel to the blade and carried by the base end movement system.

A method according to any one of the preceding claims, wherein during step d) the blade extends along the X-axis, the X-axis intersecting a vertical mast/tower axis of the support tower or mast, but rather intersecting it. extending therefrom a horizontal distance from the vertical mast/tower axis, wherein the horizontal distance corresponds to a hub overhang by which the hub extends forward from the vertical mast/tower axis when the nacelle is placed on the nacelle support.

A method according to any preceding claim, wherein a longitudinal axis (461) of the nacelle and the hub extends in a longitudinal direction of the nacelle, a radial line (245) defining a major vertical axis of the support tower or the mast and intersects a central portion of the guideway, extending at an acute angle to the longitudinal axis, the acute angle being in particular between 25 and 65 degrees, and wherein the base end support of the base end movement system extends forward from a vertical axis of the support tower or mast is located and spaced from the longitudinal axis, wherein a vertical plane extending through the base end support is oriented at an acute angle B with respect to the radial line such that the vertical plane is substantially parallel is on the front of the base end connector of the nacelle hub (46).

The method of any preceding claim, wherein the base end moving system comprises one or more actuators arranged to move the base end support a distance in the X and Y directions relative to the movable base end support base and wherein during step c) the one or more actuators are used to align the base end with the base end connector on the hub while the lifting device carries a majority of the vertical loads on the blade.

The method of any preceding claim, wherein the base end moving system further comprises at least one Z actuator configured to move the base end support a distance in the Z direction, wherein during step c) the Z actuator is used to align the base end with the base end connector on the hub while the linkage bears a majority of the vertical loads on the blade.

A method according to any preceding claim, wherein the base end movement system comprises the at least one actuator adapted to move the base end support a distance in a direction perpendicular to the X and Y directions, wherein, in particular, the direction perpendicular to the X and Y directions is at a descending angle to the horizon, and where, during step c), the Z actuator is used to align the base end with the base end connector on the hub while the linkage carries a majority of the vertical loads on the blade.

A method according to any preceding claim, wherein the base end connector of the hub comprises a rotatable ring having a plurality of holes into which threaded ends of the base end fit,

wherein in step c) the ring is rotated about the X-axis to align the threaded ends with the holes and wherein in step d) the threaded ends are inserted into the holes.

The method of any preceding claim, wherein in step c) the lifting device raises or lowers a central portion of the blade to align the base end of the blade with the base end connector of the hub about the Y axis, and /or the lifting device moves a central portion of the blade in a direction parallel or substantially parallel to the Y axis, to align the base end of the blade with the base end connector of the hub about the Z axis, more particularly the twists are used to orient the base end of the blade parallel to the base end connector of the hub.

A method according to any one of the preceding claims, wherein the lifting device supports the blade at or near the center of gravity of the blade, in particular via a lifting frame connected to the blade and extending over part of the length of the blade wherein the lifting frame is in particular the same lifting frame as that which supports the blade when engaged with the base end support.

A method according to any one of the preceding claims, wherein the lifting device comprises a crane, the blade being suspended from the lifting device by means of at least one cable attached to the lifting frame or to the blade itself.

A method according to any one of the preceding claims, wherein the crane comprises a base which is rotatable about a vertical axis and comprises a boom which extends up and out at an adjustable boom angle.

A method according to any preceding claim, wherein the blade is connected to the base end support while the blade is substantially horizontal.

The method of any preceding claim comprising repeating steps c) and d) for at least one subsequent blade and base end connector (441) until a blade is joined to two or three base end connectors of the hub.

The method of any preceding claim except claims 3-9, wherein the guideway extends over only an upper portion of the support tower or mast, the upper portion being less than 30 percent of the height of the support tower or mast, wherein the engagement position is above 70 percent of the height of the support tower or mast.

The method of any preceding claim, wherein the lifter and the base end movement system are both operated by the operator of the lifter, and wherein the operator is provided with means for monitoring the orientation of the blade relative to a fixed coordinate system and load on the blade loader due to blade orientation.

A method according to any one of the preceding claims, wherein the lifting device and the base end movement system are coupled via a control unit and the control unit is used to move the lift device and the base end movement system in tandem, wherein input data for the control unit is the vertical position of both the base end movement system and the linkage point of the linkage to the blade, and wherein the input data is used to calculate relative locations and/or speeds of the linkage point of the linkage to the blade and of the base end support.

A method according to any one of claims 3-31, wherein the lifting device and the support structure are both operated by the operator of the lifting device, and wherein the operator is provided with means to monitor the orientation of the blade relative to a fixed coordinate system and monitor the loads on the blade loader due to blade orientation.

A method according to any one of claims 3-31 and claim 34, wherein the lifting device and the support structure are coupled via a control unit and the control unit is used to move the lifting device and the base end movement system in tandem, input data for the control unit is the vertical position of both the base end movement system and the linkage point of the linkage to the blade, and wherein the input data is used to calculate relative locations and/or speeds of the linkage point of the linkage to the blade and of the base end support.

A method according to any one of claims 12-33, wherein the rail or base frame is connected to the wind turbine tower before step b) and is removed from the wind turbine tower after all blades have been connected to the hub.

A method according to any one of claims 2-36, comprising installing a wind turbine tower system at the target site with the same installation vessel or with a second, different installation vessel, the second installation vessel in particular being smaller than the first installation vessel.

A method of decoupling wind turbine blades (50) from a hub (44) of a nacelle (46) of a wind turbine at or near an offshore target site, wherein the wind turbine comprises a tower (42) and a nacelle support at the upper end of the mast, the method comprising the steps of: a) positioning an installation vessel (10) at the target location, the installation vessel comprising a lifting device (14) adapted to lift wind turbine components, and b) positioning a base end movement system (30) on the mast, the base end movement system defining a guideway extending a vertical distance, the base end movement system a movable base end support base (32) and a base end support (34) for supporting a base end of the blade includes, the base end support is connected with the movable base end support base, the movable base end the support is movable a vertical distance, c) with the base end movement system and the lifting device jointly supporting the blade in a blade removal position, and d) uncoupling the base end of the first blade from the hub, and e) jointly supporting and/or lowering the blade with the base end movement system and the lifting device to the disengagement position in a joint operation of the base end movement system and the lifting device, wherein the base end is supported by the base end support of the base end movement system and the lifting device the carries majority of the vertical loads on the blade, and f) disengaging the base end from the base end support and removing the blade from the base end movement system, and g) repeating steps c) through f) for at least at least one subsequent sheet.

A method of decoupling wind turbine blades (50) from a hub (44) of a nacelle (46) of a wind turbine at or near an offshore target site, wherein the wind turbine comprises a mast (42) and a nacelle support at the upper end of the mast, the method comprising the following steps:

a) positioning an installation vessel (10) according to claim 3 at the target location, wherein the installation vessel comprises a lifting device (14) adapted to lift wind turbine components, and b) positioning a base end movement system (30) in a release position of the blade, c) jointly supporting the blade with the base end movement system and the lifting device in an uninstall position of the blade, and d) uncoupling the base end of the first blade from the hub, and e) connecting the base end movement system with the base end movement system and jointly supporting the lifting device and/or guiding the blade down to the disengagement position in a joint operation of the base end movement system and the lifting device, the base end being supported by the base end support of the base end movement system and the lifting device supporting the majority of the vertical loads bears the leaf, and f) disengaging the base end from the base end support and removing the blade from the base end movement system, and g) repeating steps c) through f) for at least one subsequent blade.

A blade positioning system configured for positioning wind turbine blades on a nacelle hub of a wind turbine from an installation vessel at an offshore target location, the blade positioning system comprising: the installation vessel comprising: at least one lifting device arranged for lifting wind turbine components, and - a support tower (20) extending upwardly from a hull or deck of the installation vessel, the support tower comprising: o a nacelle support (22A) for supporting the nacelle, o a base end movement system (30) defining a guideway extending a vertical distance, the base end moving system comprising a movable base end support base (32) and a base end support (34) adapted to support and guide the base end of the blade , where the base end support is connected to the move base end support base, the base end support is movable along the guideway, the base end support is arranged to engage the base end of the blade in an engaged position thereof, the base end movement system is arranged to move the base end of the blade upwardly along the guideway from the engagement position to an installation position of the blade, wherein the at least one lifting device is arranged for lifting the nacelle on the support tower, the at least one lifting device and the base end movement system being arranged to jointly support a leaf and jointly lift the blade up towards the hub, during the upward movement the base end is supported by the base end support of the base end movement system and the lifting device carries a majority of the vertical loads on the blade.

A blade positioning system configured for positioning wind turbine blades on a hub of a wind turbine nacelle from an installation vessel at an offshore target location, the blade positioning system comprising: the installation vessel comprising at least one lifting device arranged for lifting wind turbine components, and — a wind turbine tower system located at the target location adjacent to the installation vessel, the wind turbine tower system comprising: o a mast (42), o a nacelle support (22B), located at an upper end of the mast and o a base end movement system (30) connected to the mast and defining a guideway extending a vertical distance, the base end movement system comprising a movable base end support base (32) and a base end support (34), arranged for supporting and guiding the base end of the blade, When the base end support is connected to the movable base end support base, the base end support is movable along the guideway, the base end support is adapted to engage the base end of the blade in an engaged position thereof, the base end movement system is adapted to raising the base end of the blade along the guideway from the engagement position to an installation position of the blade, the at least one lifting device adapted to lift the nacelle on the wind turbine tower, the at least one lifting device and the base end movement system are arranged to jointly support a blade and jointly move the blade up towards the hub, during the upward movement the base end is supported by the base end support of the base end movement system and the lifting device provides a majority of the vertical load and bears on the sheet.

A blade positioning system adapted to position wind turbine blades on a nacelle hub of a wind turbine from an installation vessel at an offshore target location, said wind turbine comprising: - a wind turbine tower system comprising: o a mast (42) o a nacelle support (22B) located at an upper end of the mast, the blade positioning system comprising: - the installation vessel comprising: o at least one lifting device adapted to lift wind turbine components, and o a support structure (70), comprising: e a positioning system (72), e a base end moving system (30) comprising a movable base end support base (32) and a base end support (34) adapted to support and guide the base end of the blade, the base end support being connected to the movable base end support base, the base end support i s adapted to engage the base end of the blade in an engaged position thereof, the base end moving system is adapted to move the base end of the blade from the engagement position to an installation position of the blade, the at least one lifting device being arranged for lifting of the nacelle on the wind turbine tower, wherein the at least one lifting device and the base end movement system are arranged to jointly support a blade and jointly move the blade towards the hub, wherein during the movement the base end is supported by the base end support of the base end movement system and the lifting device carries a majority of the vertical loads on the blade.

The blade positioning system of claim 40, 41 or 42, wherein the at least one lifting device and the base end movement system are configured to jointly support a blade and jointly move the blade downwardly away from the hub in a blade removal operation, wherein during the downward movement the base end is supported by the base end support of the base end movement system and the lifting device carries a majority of the vertical loads on the blade.

A blade positioning system according to any one of claims 40-43, wherein the base end movement system system comprises at least one rail connected to, in particular attached to, the support tower or the turbine tower, the rail having a first, upper end at the nacelle support and has a second, lower end.

A blade positioning system according to any one of claims 40 to 44, wherein a personnel support platform or a plurality of personnel support platforms are positioned along the guideway, the one or more personnel support platforms being adapted to accommodate persons assisting in maintenance of the said guideway. blade positioning system or performing this maintenance, wherein such personnel support platform is in particular located at least at the lower end of the guideway.

A blade positioning system according to any one of claims 40-45, wherein the base end moving system comprises a drive for moving the base end support base or the base end support along the guideway.

A blade positioning system according to any one of claims 40 to 48, wherein the base end moving system comprises one or more actuators arranged to move the base end support a distance in the X direction and the Y direction relative to the movable base end support base. move, where the X direction is the longitudinal direction of the blade, the Y direction is horizontal and is perpendicular to the X axis.

The blade positioning system of any one of claims 40 to 47, wherein the base end movement system further comprises at least one Z actuator adapted to move the base end support a distance in the Z direction relative to the movable base end support base. , where the Z direction is the vertical direction.

The blade positioning system of any one of claims 40-47, wherein the base end movement system further comprises at least one actuator adapted to move the base end support a distance perpendicular to the X and Y directions relative to the movable base end support base. , wherein, in particular, the direction perpendicular to the X and Y directions is at a descending angle to the horizon.

A blade positioning system according to any one of claims 40-49, wherein the base end support is rotatable with respect to the support tower or with respect to the mast about the Y-axis and/or the Z-axis, and rotation of the supported blade around the Y-axis and/or Z-axis.

A blade positioning system according to the preceding claim, wherein the Y-axis and/or the Z-axis are offset from the base end support by an offset distance which in particular corresponds substantially to a horizontal distance between the base end support and the base end support. base end connector of the hub when the base end engages the base end connector.

A blade positioning system according to any one of claims 40-51, wherein the base end movement system, the base end support base and the base end support are not adapted to support the nacelle.

A blade positioning system according to any one of claims 40-52, wherein the base end support comprises a bottom portion that includes a recess having a rounded shape that faces upwardly and is adapted to engage and engage the base end of a blade. support when the blade is in a horizontal or substantially horizontal position.

The blade positioning system of the preceding claim, wherein the base end support comprises a first projection and a second projection extending upwardly from the bottom portion and defining a retaining space between them, the first and second projections having rounded edges on the retaining space side. wherein the rounded edge is adapted to engage the base end without damaging the base end, the first and second projections having respective upper ends defining a gap that allows a base end of a blade through the gap to to lower it onto the bottom part.

The blade positioning system of the preceding claim, wherein at least one of the first and second projections is movable toward and away from the other projection to grip the base end.

The blade positioning system of any one of claims 46-55, wherein the movable base end support base extends outwardly from the rail, and wherein the base end support defines a horizontal longitudinal axis along which a blade extends when the base end of said blade passes through the base end. - support is supported, and wherein the horizontal longitudinal axis does not intersect a vertical axis of the support tower or the mast, but instead extends a horizontal distance from the vertical axis of the mast corresponding to a hub overhang through which the hub extends extending forward from the vertical mast/tower axis when the nacelle is positioned on the nacelle support.

A blade positioning system according to any one of claims 40 to 56, wherein a longitudinal axis (461) of the nacelle and the hub extends in a longitudinal direction of the nacelle, a radial line (245) defining a major vertical axis of the support tower or the mast and intersects a central portion of the guideway, extending at an acute angle to the longitudinal axis, the acute angle being in particular between 25 and 65 degrees, and wherein the base end support of the base end movement system extends forward from a vertical of the support tower or mast and spaced from the longitudinal axis, wherein a vertical plane extending through the base end support is oriented at an acute angle B with respect to the radial line so that the vertical plane in is substantially parallel to the front of the base end connector of the nacelle hub (48).

A blade positioning system according to any one of claims 40 to 57 except 56, wherein the base end movement system comprises a rack, the rack adapted to be engaged by a gear of the movable base end support base.

A blade positioning system according to any one of claims 40-58, wherein the at least one lifting device is a crane separated from the support tower and separated from the wind turbine tower, respectively.

A blade positioning system according to the preceding claim, wherein the crane comprises a dome which is rotatable about a vertical dome axis and comprises a boom which extends up and out at an adjustable boom angle.

A blade positioning system according to any one of claims 40 to 80, wherein the base end movement system is equipped with one or more sensors to measure the loads of the blade on the base end support, the base end movement system further comprising a screen on which the loads are visualized for the operator of the lifting device.

A blade positioning system according to any one of claims 40 to 81, wherein the base tip movement system is equipped with one or more sensors to measure the orientation of the blade in terms of angles relative to a fixed coordinate system, the base tip movement system further comprising a screen, on which the orientation is made visible to the operator of the lifting device.

A blade positioning system according to any one of claims 40 to 82, comprising a control unit, wherein the base end movement system and the lifting device are both connected to the control unit, the control unit being adapted to move the lifting device and the base end movement system in tandem, input data for the control unit include a vertical position of the base end movement system and of the linkage point of the linkage to the blade obtained from one or more sensors, and wherein the data controller calculates relative locations and/or speeds of the linkage point of the linkage and of the base end support and controls at least one winch of the lifting device and a drive of the base end movement system to keep the blade horizontal or substantially horizontal.

A blade positioning system according to any one of claims 40 to 83, wherein the base end movement system comprises one or more brakes and/or dampers to limit or dampen rotation of the base end support about the Y-axis or Z-axis.

A blade positioning system according to any one of claims 40-64, wherein the installation vessel is a floating installation vessel.

A blade positioning system according to any one of claims 40-84, wherein the installation vessel is a non-floating installation vessel, in particular a jack-up platform.

A blade positioning system according to any one of claims 40 to 66 except 42, wherein the guideway extends the entire height of the mast.

A blade positioning system according to any one of claims 40 to 87 except 42, wherein the guideway extends over only an upper portion of the mast, more particularly up to the upper 30 percent of the mast.

69. A base end movement system comprising a movable base end support base (32) and a base end support (34) for supporting a base end of a blade, the base end support being connected to the movable base end support base.

The base end movement system of claim 69, comprising any of the features of claims 44, 46-50, 53-55, 58, 81 and/or 62.

71. A wind turbine tower system comprising: — a tower (42), — a nacelle support at an upper end of the tower, and — a base end movement system (30) connected to the tower and defining a guideway extending a vertical distance wherein the base end movement system comprises a movable base end support base (32) and a base end support (34) adapted to support and guide the base end of the blade, the base end support being connected to the movable base end support base, the base end support base base end support is movable along the guideway, the base end support is arranged to engage the base end of the blade in an engaged position thereof, the base end moving system is arranged to raise the base end of the blade along the guideway from the engagement position to an installation position of the blade.

The wind turbine tower system of the preceding claim, wherein the guideway comprises at least one rail connected to the tower, the rail having a first, lower end and a second, upper end, the upper end being at the nacelle support and the lower end is below the upper end.

The wind turbine tower system of claim 71 or 72, wherein the guideway extends over only an upper portion of the support tower or mast, the upper portion being less than 30 percent of the height of the support tower or mast, the engagement position being above 70 percent. percent of the height of the support tower or mast.

A wind turbine tower system according to any one of claims 71-73, wherein the base tip movement system is one of the features of claims 4-15, 17, 19-20, 24, 31-39, 44-486, 50, 56-58, 67-68 .

A support structure comprising: - a positioning system, - a base end movement system (30), comprising a movable base end support base (32) and a base end support (34) adapted to support and guide a base end of a blade, wherein the base end support is connected to the movable base end support base, the base end support is arranged to engage the base end of the blade in an engaged position thereof, the base end moving system is adapted to move the base end of the blade from the engagement position to an installation position of the blade.

The support structure of claim 75, wherein the base end movement system is connected to the positioning system via one or more actuators that create one or more degrees of freedom for the base end movement system relative to an installation vessel when a mast stop engages a mast.

A support structure according to any one of claims 75-76, wherein the movement of the movable base end support base engages the mast stop on the mast.

A support structure according to any one of claims 75-77, wherein the positioning system comprises any of the features of claims 4-9, 34-35, 39 and 42.

The support structure of any of claims 75, 78, wherein the base end movement system has any of the features of claims 3-15, 18, 20-22, 24, 32-35, 39, 45, 47, 55, 57-58, 61- 64, and 69-70.