Installation of a wind turbine on a floating foundation

Abstract

For example, at the site of an offshore wind farm, a wind turbine is installed on a floating foundation, which is in a floating state and subjected to movements caused by sea conditions. A vessel with a crane is used, the crane being arranged on the hull and provided with a lifting system adapted to support the weight of the wind turbine and to suspend the wind turbine on the crane. A heave compensation device compensates for the heave movement of the wind turbine mast with respect to the mast mounting structure of the floating foundation caused by sea conditions. A mast alignment system is used, which is configured to engage on the suspended wind turbine, for example on the mast of the suspended wind turbine, and which is configured to align and keep aligned the mast of the wind turbine with the mounting axis of the floating foundation, to compensate for the movement of the wind turbine mast with respect to the mounting axis of the floating foundation caused by sea conditions, which movement comprises at least a tilting movement in one or more vertical planes.

Description

Technical Field

[0001] This invention relates to the installation of a wind turbine on a floating base. Background Technology

[0002] In the field of offshore wind farms, it is known to install a fixed base, such as a support or monopile, on the seabed, and then mount the wind turbine on top of the fixed base. The latter is typically accomplished in a step-by-step manner, for example, where the mast is first installed on a pre-installed base, then the nacelle is mounted on top of the mast, and finally the rotor blades are assembled onto the nacelle's hub. Other methods, such as providing a nacelle with two rotor blades (out of three) already assembled in a so-called rabbit-ear configuration, are also known.

[0003] Fixed-base offshore wind turbines are highly effective in relatively shallow waters. In deeper waters, floating-base wind turbines are expected to be the most economical, for example. For instance, patent document WO2009 / 131826 discloses several designs for floating-base wind turbines.

[0004] In the field of floating base wind turbines, it is generally accepted that the assembly of the entire floating base wind turbine, i.e., the combination of the floating base and the wind turbine, is completed far from the actual wind farm. For example, assembly is completed at a port terminal. The entire floating base wind turbine is then towed from the assembly site to the remote offshore wind farm location.

[0005] For example, Hywind Scotland is a wind farm that uses floating-base wind turbines. These turbines have 120-meter-high masts mounted on spar-type floating bases. The wind turbines are installed on the spar-type floating bases using a Saipem 7000 floating crane in the Norwegian fjords. These components are then towed across the North Sea to the Scottish coast near Peterhead. At the wind farm, three suction anchors hold the floating bases to the seabed. Summary of the Invention

[0006] The present invention aims to provide an alternative method for assembling floating base wind turbines and / or for creating wind farms having one or more floating base wind turbines.

[0007] The present invention provides a method for mounting a wind turbine on a floating base, the floating base being in a floating state and subject to movement caused by sea conditions.

[0008] Preferably, the installation is completed at the offshore wind farm site. It should be understood that this avoids the need for long-distance towing of the entire wind turbine from its shore-based location, such as a dock, to the wind farm. Such towing requires considerable effort, is time-consuming, and can be affected by weather conditions.

[0009] More preferably, before the wind turbine is installed on the base, the floating base has been anchored to the seabed at the final location in the wind farm, for example by at least a portion of the anchoring device.

[0010] The wind turbine to be installed includes a wind turbine mast with a lower end, and a rotor assembly with rotor blades mounted on the wind turbine mast. Preferably, the mast of the wind turbine to be installed can be a single mast, but it can also consist only of an upper mast section, with the lower mast section integrated with the floating base.

[0011] The floating base includes a mast mounting structure configured to mount the mast of a wind turbine onto the mast mounting structure, and the mast mounting structure has an upward-pointing mounting axis. The base can be any design, such as any design disclosed in WO2009 / 131826.

[0012] For example, a floating base includes three or more interconnected and floating stabilizing columns, such as three stabilizing columns interconnected by beams arranged in a triangular (e.g., equilateral triangle when viewed from above) shape.

[0013] For example, a floating base (e.g., each buoyancy column of the floating base) is provided with one or more ballast tanks for containing ballast material, such as ballast fluid, for example, ballast water. In one embodiment, a ballast control system is provided, configured to move the ballast fluid between the ballast tanks of, for example, at least three stabilizing columns to adjust the vertical direction of the upward-pointing installation axis.

[0014] In the implementation scheme, one of the stabilizing columns of the floating base is provided with a mast mounting structure configured to mount the mast of the wind turbine onto the mast mounting structure.

[0015] In the implementation, the floating base includes one or more water-collecting plates, for example, each of which is attached to the lower end of one of the stabilizing columns.

[0016] The method uses a vessel comprising:

[0017] - Floating hulls, such as semi-submersible vessels, or non-elevator vessels.

[0018] - A crane, which is mounted on the hull.

[0019] The crane is equipped with a lifting system suitable for supporting the weight of the wind turbine and suspending the wind turbine on the crane. This lifting system is adapted to raise and lower the wind turbine in a controlled manner.

[0020] At offshore wind farm sites, unlike the installation locations of (protected) shore-based (e.g., docks), wave conditions can be more pronounced (year-round), so floating bases and crane vessels will be affected by sea conditions, each typically exhibiting its own dynamic behavior.

[0021] Ship cranes and / or their lifting systems include heave compensation devices adapted to compensate for heave movements of the wind turbine mast relative to the mast mounting structure of the floating base caused by sea conditions. Particularly for lifting devices with one or more lifting winches and lifting cables, as preferred herein, suitable heave compensation devices are well known in the art, whether passive, active, or a combination thereof. For example, the lifting device includes one or more winches and one or more lifting cables, with heave compensation achieved by proper operation of the (electric) winches and / or by one or more heave compensation cylinders carrying one or more cable pulleys, wherein the lifting cable passes through one or more cable pulleys.

[0022] The method uses a mast alignment system configured to engage with a suspended wind turbine, such as the mast of a suspended wind turbine, and configured to align and maintain alignment between the mast of the suspended wind turbine and the mounting axis of the floating base to compensate for movement of the wind turbine mast relative to the mounting axis of the floating base caused by sea conditions, including tilting movements in at least one or more vertical planes.

[0023] The method includes the following steps—when the ship's hull is floating and the floating base is floating:

[0024] - The wind turbine is suspended on a crane using a lifting system.

[0025] - The lower end of the mast of the suspended wind turbine is positioned above the mast mounting structure of the floating base.

[0026] - Operate the heave compensation device to compensate for the heave motion of the wind turbine mast relative to the mast mounting structure of the floating base caused by sea conditions.

[0027] - Operate the mast alignment system to align and maintain alignment between the wind turbine mast and the mounting axis of the floating base, compensating for tilting movements of the wind turbine mast relative to the mounting axis of the floating base caused by sea conditions.

[0028] - When the heave compensation device and mast alignment system are in operation, operate the lifting system to lower the suspended wind turbine and the lower end of the mast together onto the mast mounting structure of the floating base.

[0029] - A mast mounting structure that secures the mast and its lower end to the floating base.

[0030] Therefore, this method envisions providing and operating a mast alignment system to enable the lower end of the mast to be correctly lowered onto the mast mounting structure of the floating base. Generally, the mast alignment system is used to force the suspended wind turbine off its vertical direction so that its mast is aligned with and remains aligned with the mounting axis, which is continuously subjected to at least tilting motion relative to the mast due to sea conditions acting on the floating hull and floating base of the vessel.

[0031] For example, this invention enables the anchoring of multiple floating bases at their final locations within an offshore wind farm, all without wind turbines, followed by the descent of a vessel to the wind farm and the sequential installation of wind turbines onto the floating bases. This method allows for a more (economically) efficient way to establish floating base offshore wind farms compared to the methods mentioned above, where fully assembled floating wind turbines must be towed over a relatively long distance to their locations within the wind farm. In this embodiment, the floating bases for the wind farm are installed within one calendar year, with the associated wind turbines installed on these bases in subsequent calendar years.

[0032] For example, the present invention can use a deep-draft floating base, such as a cylindrical base, which does not require a deep-draft installation location close to the coast as in the fjords mentioned above.

[0033] In the implementation, lowering the mast onto the mast mounting structure may facilitate or subsequently establish initial fastening between the mast and the base, thereby stabilizing the wind turbine relative to the base, for example, enabling the cessation of the alignment system's operation, or enabling the removal of the alignment system.

[0034] For example, the lower end of the mast is configured for insertion into or over a mast mounting structure on the floating base, the insertion providing a stable initial fastening between the mast and the base. Alternatively, the lower end of the mast and the floating base are configured to establish a sliding joint connection. Typically, a sliding joint comprises one or more pairs of mating tapered engagement surfaces. In another embodiment, the mast consists of a lower mast section and an upper mast section, with the sliding joint connecting the two mast sections, for example, the lower mast section already mounted to the floating base. Providing a sliding joint allows for relatively quick installation and can optionally facilitate later disassembly of the wind turbine. For example, in a sliding joint connection, the relative angular orientation of the mating portions (affected by sea conditions) may be less important compared to a conventional flange connection using only bolts.

[0035] In the example, one or more preliminary fastener devices are provided on the lower end and / or mast mounting structure, which, for example automatically or by command, establish preliminary fastening between the mast and the base. Final fastening from the lower end to the mast mounting structure can then be performed, for example, by providing a connection through bolts, welding, grouting, etc.

[0036] In one implementation, the lower end of the mast and the mast mounting structure are provided with cooperative self-actuating fastening members (e.g., like an automatic latch) that fasten the mast to the base.

[0037] In the implementation, at least the mast alignment system remains operational during some or all of the fastening steps, for example, in which the system is used or assists in stabilizing the wind turbine relative to the base.

[0038] In one embodiment, at least the heave compensation device remains operational during some or all of the fastening steps; for example, the device is also used in this step to support at least a portion of the weight of the wind turbine relative to the base. In another embodiment, once the lower end of the mast has been lowered onto the mast mounting structure of the floating base, the weight of the wind turbine is transferred from the crane to the floating base. This can be accomplished, for example, through the appropriate operation of the lifting system and / or the heave compensation device.

[0039] In the preferred installation method—at least in the step of lowering the mast onto the base—the vessel faces the waves with its bow or stern. Most preferably, the vessel is configured to suspend the wind turbine at its bow or stern, preferably at the midplane of the vessel.

[0040] In practical implementations, as is known in the art, vessels are equipped with dynamic positioning systems, commonly referred to as DP systems. For example, water depth may prevent vessels with anchors from mooring on the seabed.

[0041] Preferably, during the wind turbine installation process, the floating base is constrained, at least to some extent, by a restraint system, at least in the horizontal plane relative to the vessel. This restraint may, for example, involve multiple mooring lines (e.g., at least three mooring lines) arranged between the floating base and the hull in different directions to provide a connection between the floating base and the hull, at least in the horizontal plane.

[0042] In the implementation plan, the restraint system is located at the bow of the semi-submersible vessel.

[0043] The constraint of the floating base can also involve, for example, the use of a clamping device mounted on a vessel, such as a monopile clamp known for installing monopiles in the seabed, having an engagement member, such as a ring member, engaged with the floating base (e.g., on the mast mounting structure of the floating base), and having an active controlled motion mechanism configured and operated to provide controlled movement of the engagement member relative to the hull of the vessel, and thereby providing controlled constraint of the engaged floating base relative to the hull of the vessel. For example, the active controlled motion mechanism is implemented to actively constrain the engaged floating base relative to the hull of the vessel in at least one horizontal direction, possibly in two non-parallel horizontal directions, such as in orthogonal horizontal directions.

[0044] In the implementation scheme, the vessel is provided with tensioner lines, preferably at least two tensioner lines, which are configured to secure the vessel to the base and to reduce vertical movement of the floating base relative to the vessel.

[0045] Even when using a constraint system that at least partially restricts the movement of the mast mounting structure relative to the ship in the horizontal plane, or when such constraint is absent, embodiments of the invention envision the mast alignment system also configured to compensate for horizontal movement of the wind turbine mast relative to the mounting axis of the floating base caused by sea conditions in at least one horizontal direction, for example, in two non-parallel horizontal directions, such as two orthogonal horizontal directions. In this embodiment, in addition to the aforementioned relative tilting movement, the alignment system is also responsible for the relative horizontal movement of the lower end of the mast and the mast mounting structure.

[0046] In one embodiment, the alignment system includes at least one mast engagement device having a mast engagement member and an active controlled motion mechanism configured and operated to provide controlled movement of the mast engagement member in the horizontal plane to align and maintain alignment of the mast of the suspended wind turbine with the mounting axis of the floating base. At least one mast engagement device is typically conceived to actively force the suspended wind turbine away from its vertical orientation and align it with the mounting axis.

[0047] In the implementation scheme, the alignment system includes an upper mast engagement device and a lower mast engagement device, each device having a mast engagement member and an active controlled motion mechanism configured and operated to provide controlled movement of the mast engagement member in the horizontal plane, wherein the mast engagement devices act on the mast at different heights, for example, the lower one below the center of gravity of the wind turbine to be installed, and the higher one above the center of gravity, and wherein the active controlled motion mechanism is operated to align and maintain alignment of the mast of the suspended wind turbine with the mounting axis of the floating base. For example, the upper and lower mast engagement devices are at least 20 meters apart in the vertical direction.

[0048] In a possible implementation, the active controlled horizontal motion mechanism includes a first set of one or more horizontal rails extending in a first horizontal direction, the first set of one or more horizontal rails supporting at least one first carrier, and the one or more first carriers supporting a second set of one or more horizontal rails extending in a second horizontal direction different from the first direction, for example, the first and second directions are orthogonal, the second set of one or more horizontal rails supporting one or more additional second carriers supporting the mast engagement device.

[0049] In practical implementations, the active controlled horizontal motion mechanism includes one or more horizontal displacement actuators, such as hydraulic cylinders or assemblies of one or more cables and associated (electric) winches, or rack and pinion drives.

[0050] In an embodiment, at least one (preferably each) mast engagement device of the alignment system includes, for example, a trolley vertically guided along one or more vertical guides, such as those mounted on the hull of a vessel and / or a crane, the trolley supporting a mast engagement member, and an active controlled motion mechanism inserted between the trolley and the mast engagement member to provide controlled movement of the mast engagement member in the horizontal plane, for example, in two orthogonal horizontal directions. It should be understood that, herein, vertical and horizontal are rough representations of the movement of the vessel caused by sea conditions.

[0051] In the implementation, the trolley of the mast engagement device, such as the trolley of the upper mast engagement device, is suspended from a crane. For example, the upper mast engagement device is suspended from the crane by the same lifting system that suspends the wind turbine, and is subjected to the same heave compensation device, such that the trolley moves in unison with the heave compensation movement of the wind turbine.

[0052] In one embodiment, the alignment system includes a mast engagement device, such as an upper mast engagement device, comprising trolleys vertically guided, for example, along one or more vertical guides mounted on the hull of a vessel and / or a crane. The trolleys support a mast engagement member. An active, controlled motion mechanism is inserted between the trolleys and the mast engagement member to provide controlled movement of the mast engagement member in a horizontal plane, for example, in two orthogonal horizontal directions, wherein a wind turbine is suspended from the mast engagement member, and wherein the mast engagement member is suspended from a crane via a lifting device. In another embodiment, one or more suspension cables extend between an attachment member assembled (e.g., temporarily assembled) on the mast at a height below the upper mast engagement device and the mast engagement member. In the implementation scheme, the crane is provided with a first and second horizontally spaced-apart upper pulley group and the mast joint member is provided with a first and second horizontally spaced-apart lower pulley group. A first multi-rope cable device extends between the first and second upper pulley groups, and a second multi-rope cable device extends between the second upper and second lower pulley groups. Preferably, this configuration ensures that the nacelle and a blade of the upward-pointing wind turbine are located between the multi-rope cable devices, which do not contact either the blade or the nacelle.

[0053] In one embodiment, the crane has a vertical crane structure erected on the hull of a vessel, for example having a pivot arm at its top, wherein the lifting device includes one or more winch drive cables hanging from one or more pulley blocks arranged on the pivot arm.

[0054] In one embodiment, the vertical crane structure has a lower section of the crane structure fixed to the hull and a rotatable top section of the crane structure, wherein the lifting device includes, for example, one or more winch drive cables on a pivot arm of the rotatable top section, which hang from one or more pulley blocks arranged on the rotatable top section. In another embodiment, the rotation of the top section can be used to retrieve assembled wind turbines from the deck of the vessel via the lifting device and to bring the wind turbines with masts above the mast mounting structure of the floating base.

[0055] In one embodiment, the alignment system is mounted on a vertical crane structure that is erected on the hull of a vessel and subjected to motion caused by sea conditions similar to those of the vessel's hull. For example, the alignment system includes one or more mast engagement devices mounted on the vertical crane structure, each implemented as described herein.

[0056] In the implementation scheme, the rotatable top section of the vertical crane structure is provided with an upper mast engagement device, and the fixed lower section of the vertical crane structure is provided with a lower mast engagement device. For example, a vertical guide rail is provided on the rotatable top section for a pulley of the upper mast engagement device. For example, a vertical guide rail is provided on the lower section for a pulley of the lower mast engagement device.

[0057] For example, when it is desired to attach a wind turbine above or near its center of gravity, the height of the crane structure must be more than 75 meters above the waterline, and possibly more than 100 meters.

[0058] In the implementation scheme, the vessel is a type referred to as a semi-submersible vessel, having a pair of substantially parallel, laterally spaced buoyancy pontoons (e.g., with ballast tanks) to allow the pontoons to move between an underwater state and a surface-floating state, and the vessel has a row of multiple columns supported by each pontoon and extending upward from each pontoon, and a deck structure supported by the upper ends of the columns. A crane is mounted on the deck structure of the hull.

[0059] In the implementation plan, the semi-submersible vessel has a bow and a stern, wherein a crane is mounted on the bow, for example, on a deck structure between two pontoons (viewed from above), with the bow end of the deck structure located aft of the pontoon bow.

[0060] In the implementation, the floating base has a stabilizing post (viewed from above) at its corner, on which the wind turbine will be mounted, for example, on a triangular base, as described in WO2009 / 131826, wherein the semi-submersible vessel and its pontoon, for example, the bow portion of the semi-submersible vessel, are arranged on opposite sides of the stabilizing corner, and a crane suspends the mast of the wind turbine above the mast mounting structure on the stabilizing post.

[0061] In this implementation, one or more sensors are used to monitor the movement of the mast mounting structure relative to the lower end of the mast in one or more directions during installation. Preferably, these one or more sensors are linked to a controller, such as a computerized controller, configured and operated to automatically activate the heave compensation device and / or alignment system. For example, the one or more sensors may be implemented as one or more cameras, radars, displacement sensors, etc.

[0062] For example, one or more motion monitoring sensors can be combined with the constraint system discussed in this paper.

[0063] For example, one or more motion monitoring sensors are configured to monitor the tilt of the mast mounting structure relative to the ship's hull, such as relative to the restraint system, such as about the vertical horizontal axis, such as corresponding to the ship's pitch and roll directions.

[0064] In the implementation, the restraint system includes at least three mooring lines that secure the floating base to the vessel, for example, to the bow of the vessel, with the mooring lines extending in different directions, for example, primarily on the horizontal plane. This allows for maintaining a substantially fixed relative horizontal position between the vessel and the floating base. Preferably, the base is anchored to the seabed in this configuration.

[0065] In the implementation plan, in addition to a portion of the vessel being attached to an anchored floating base via a restraint system, the vessel is anchored to the seabed via multiple anchor cables. For example, during installation, the restraint system attaches the bow of the vessel (e.g., a semi-submersible vessel) to the floating base (e.g., the stabilizing post of the floating base) and one or more anchor cables extend from the stern.

[0066] In the implementation scheme, the restraint system may also include, for example, one or more tension line assemblies arranged on the vessel, each tension line assembly including one or more tension lines and one or more corresponding tensioning devices that provide controlled tension to the tension lines connected to the floating base. The tension line assemblies are configured and operated to tension the one or more lines, thereby restraining the floating base primarily in the heave direction relative to the vessel.

[0067] It should be noted that the vessel may only be used for installation procedures, while the supply of the assembled wind turbines is carried out by another vessel, such as a barge, from an onshore location.

[0068] Preferably, the assembly of the wind turbine to be installed is completed, at least for complete completion, on an installation vessel equipped with a crane for mounting the wind turbine onto a floating base. For example, the mast is provided to or stored on the vessel in two parts (i.e., a lower mast section and an upper mast section). For example, the nacelle is provided to or stored on the vessel. For example, the blades are provided to or stored on the vessel. The assembly of the wind turbine is then completed on the vessel, for example, in which the final stage is installation on the floating base as described herein. For example, in a first assembly stage, the nacelle is installed on the upper mast section. Then, in a second assembly stage, the blades are assembled onto the hub, for example, involving the methods and apparatus described in, for example, as described in, NL2026734 (not previously disclosed), which is incorporated herein by reference. Then, in a third assembly stage, the sub-assemblies are lifted and placed on top of the lower mast section, where the mast sections are secured to each other to complete the wind turbine assembly. The assembly is then installed on the floating base as described herein. In embodiments, additional cranes are provided on the vessel to handle the mast sections and / or the nacelle and / or the blades during assembly. Other cranes can also be used to load such wind turbine components from supply vessels (e.g., barges) onto ships.

[0069] In the implementation plan, it is envisioned that the lower mast section is already installed on the floating base, for example, during its production process. For example, the height of the lower mast section is at least 30% of the total mast height. The upper mast section, nacelle, and rotor blade sub-assemblies are then lifted and installed on top of the lower mast section, with the mast sections secured to each other.

[0070] For example, a vessel sails to a wind farm already anchored on a floating base. The vessel carries multiple wind turbines in an unassembled state stored on the vessel, such as at least five wind turbines. For instance, the upper mast section, lower mast section, nacelle, and rotor blades of at least five wind turbines are stored separately on the vessel. In another embodiment, the nacelle already has two blades arranged in a so-called rabbit-ear configuration.

[0071] In one embodiment, the vessel includes one or more quick-fill ballast tanks configured to hold ballast water below the waterline. The quick-fill ballast tanks include ballast water filling doors located below the waterline for dumping seawater into the quick-fill ballast tanks, for example, during and / or after lowering the mast onto the floating base, to compensate for the weight transfer from the vessel to the base caused by the placement of the wind turbine onto the floating base.

[0072] In one implementation, the floating base is provided with one or more quick-release ballast water tanks configured to hold ballast water above the waterline. The quick-release ballast water tanks include ballast water dumping doors, preferably located above the waterline, for dumping ballast water, for example, during and / or after lowering the mast onto the floating base, to compensate for the weight transfer from the ship to the base caused by the lowering of the wind turbine.

[0073] It should be noted that, in alternative implementations, other water-filling and / or ballast dumping devices may be provided in addition to or as alternatives to water-pouring and water-filling doors.

[0074] In one implementation, the alignment system is suspended on a crane, for example, on a lifting device similar to that used for wind turbines.

[0075] In the implementation plan, the alignment system is temporarily placed on a floating base.

[0076] The present invention further provides a floating base, for example for supporting a wind turbine, wherein the floating base is provided with one or more quick-release ballast tanks for maintaining ballast water above the waterline. The quick-release ballast tanks include ballast water dumping doors, preferably located above the waterline, for dumping ballast water, for example during and / or after lowering the mast onto the floating base, to compensate for the weight transfer from the vessel to the base caused by moving the wind turbine. The invention also relates to the use of such a floating base, for example, in the process of installing a wind turbine on a floating base. In an embodiment, a vessel using such a floating base includes one or more quick-fill ballast tanks configured to maintain ballast water below the waterline. The quick-fill ballast tanks include ballast water filling doors for dumping seawater into the quick-fill ballast tanks, for example during and / or after lowering the mast onto the floating base, to compensate for the weight transfer from the vessel to the base caused by placing the wind turbine onto the floating base.

[0077] The present invention also relates to a system for mounting a wind turbine on a floating base, which is floating at the site of an offshore wind farm and subject to movement caused by sea conditions.

[0078] The wind turbine to be installed includes at least a portion of a wind turbine mast having a lower end, and includes a rotor assembly with rotor blades mounted on the wind turbine mast.

[0079] The floating base includes a mast mounting structure configured to mount the mast of the wind turbine onto the mast mounting structure, and the mast mounting structure has an upward-pointing mounting axis.

[0080] The system includes ships, which include:

[0081] - Floating hull

[0082] - A crane, which is mounted on the hull.

[0083] The crane is equipped with a lifting system suitable for supporting the weight of the wind turbine and suspending the wind turbine on the crane. This lifting system is suitable for raising and lowering the wind turbine in a controlled manner.

[0084] The ship's cranes and / or lifting systems include heave compensation devices adapted to compensate for the heave motion of the wind turbine mast relative to the mast mounting structure on the floating base caused by sea conditions.

[0085] The system further includes a mast alignment system configured to engage with, for example, the mast of a suspended wind turbine, and configured to align and maintain alignment between the wind turbine mast and the mounting axis of the floating base to compensate for movement of the wind turbine mast relative to the mounting axis of the floating base caused by sea conditions, including tilting movements in at least one or more vertical planes.

[0086] The system is configured to be used in a method that includes the following steps—when the ship's hull is floating and the floating base is floating:

[0087] - The wind turbine is suspended on a crane using a lifting system.

[0088] - The lower end of the mast of the suspended wind turbine is positioned above the mast mounting structure of the floating base.

[0089] - Operate the heave compensation device to compensate for the heave motion of the wind turbine mast relative to the mast mounting structure of the floating base caused by sea conditions.

[0090] - Operate the mast alignment system to align and maintain alignment between the wind turbine mast and the mounting axis of the floating base, compensating for tilting movements of the wind turbine mast relative to the mounting axis of the floating base caused by sea conditions.

[0091] - When the heave compensation device and mast alignment system are in operation, operate the lifting system to lower the suspended wind turbine and the lower end of the mast together onto the mast mounting structure of the floating base.

[0092] - A mast mounting structure that secures the mast and its lower end to the floating base.

[0093] The system, such as a ship and / or its mast alignment system, may include one or more features discussed herein with reference to the methods of the present invention.

[0094] The present invention also relates to an alignment system for mounting a wind turbine on a floating base as described herein.

[0095] The present invention also relates to cranes mounted on ships and alignment systems for mounting wind turbines on floating bases as described herein.

[0096] The present invention also relates to vessels equipped with cranes and alignment systems for mounting wind turbines on floating bases as described herein.

[0097] The invention also relates to vessels equipped with cranes and restraint systems for mounting wind turbines on floating bases as described herein, for example, in the absence of alignment systems as described herein.

[0098] The present invention also relates to a method for constructing an offshore wind farm, wherein multiple floating bases already exist at the wind farm site, preferably already anchored in their final positions, and wherein the vessels used include:

[0099] - A floating hull with a deck.

[0100] - Cranes mounted on the hull

[0101] The crane is equipped with a lifting system suitable for supporting the weight of the wind turbine and suspending the wind turbine on the crane. This lifting system is suitable for raising and lowering the wind turbine in a controlled manner.

[0102] The ship's cranes and / or lifting systems include heave compensation devices adapted to compensate for the heave motion of the wind turbine mast relative to the mast mounting structure on the floating base caused by sea conditions.

[0103] In this method, a vessel sails to a wind farm already anchored on a floating base. The vessel has multiple wind turbines stored on the vessel in an unassembled state, for example, at least five wind turbines. The masts (e.g., upper mast section, lower mast section), nacelles, and rotor blades of at least five wind turbines are stored separately on the vessel.

[0104] And this method includes assembling the wind turbine to be installed onto the ship.

[0105] And the method includes the following steps—when the ship's hull is floating and the floating base is floating:

[0106] - The wind turbine is suspended on a crane using a lifting system.

[0107] - The lower end of the mast of the suspended wind turbine is positioned above the mast mounting structure of the floating base.

[0108] - Operate the heave compensation device to compensate for the heave motion of the wind turbine mast relative to the mast mounting structure of the floating base caused by sea conditions.

[0109] - Possibly, operate the mast alignment system to align and maintain alignment of the wind turbine mast with the mounting axis of the floating base, in order to compensate for tilting movements of the wind turbine mast relative to the mounting axis of the floating base caused by sea conditions.

[0110] - When the heave compensation device and mast alignment system are in operation, operate the lifting system to lower the suspended wind turbine and the lower end of the mast together onto the mast mounting structure of the floating base.

[0111] - A mast mounting structure that secures the mast and its lower end to the floating base.

[0112] Preferably, a mast alignment system is used, which is configured to engage with a suspended wind turbine, such as the mast of a suspended wind turbine, and is configured to align and maintain alignment between the wind turbine mast and the mounting axis of the floating base to compensate for movement of the wind turbine mast relative to the mounting axis of the floating base caused by sea conditions, including tilting movements in at least one or more vertical planes.

[0113] Preferably, all rotor blades are stored horizontally on the vessel, for example, stacked along one side of the vessel, and all rotor blades are mounted to the hub, for example as described in NL2026734, which is incorporated herein by reference.

[0114] Preferably, the vessel is a semi-submersible vessel. Attached Figure Description

[0115] The invention will now be described in detail with reference to the accompanying drawings. In the drawings:

[0116] - Figure 1 The installation of a wind turbine according to the invention on a floating base is shown.

[0117] - Figure 2 The installation is shown in a top view.

[0118] - Figure 3 The installation is shown in a front view, with the wind turbine suspended vertically from the ship's crane.

[0119] - Figure 4 Shown in side view Figure 3 Installation,

[0120] - Figure 5 yes Figure 4 An enlarged view of the portion showing the upper mast assembly and the suspension of the wind turbine.

[0121] - Figure 6 Shown in front view Figure 5 Part of

[0122] - Figure 7 yes Figure 4 The enlarged view shows the lower mast connection and the restraint system acting on the stabilizing columns of the floating base.

[0123] - Figure 8 The operation of the alignment system of the present invention is shown in a front view.

[0124] - Figure 9The operation of the alignment system of the present invention is shown in a side view.

[0125] - Figure 10 yes Figure 8 An enlarged view of the portion showing the upper mast assembly.

[0126] - Figure 11 yes Figure 9 The enlarged view shows the lower mast connection and the restraint system acting on the stabilizing columns of the floating base.

[0127] - Figure 12 Shown in front view Figure 11 Part of

[0128] - Figure 13a , Figure 13b , Figure 13c The upper mast engagement device of the alignment system is shown.

[0129] - Figures 14a-14e The upper mast engagement assembly of the crane and alignment system is shown.

[0130] - Figure 15 The diagram shows a pre-assembled assembly with the upper mast, nacelle, and rotor blades mounted on a floating base that already has the lower mast section.

[0131] - Figure 16a , Figure 16b It shows in Figure 15 The method involves the operation of the alignment system. Detailed Implementation

[0132] The accompanying drawings show the installation of a wind turbine 1 on a floating base 100, which is floating and subject to movement caused by sea conditions, for example, at the site of an offshore wind farm.

[0133] The wind turbine 1 to be installed includes at least a portion of a wind turbine mast 2 having a lower end, and includes a rotor assembly, here implemented as a nacelle 3 with a hub and rotor blades 4, which has been mounted on the wind turbine mast 2.

[0134] The floating base 50 is shown as an example with the design detailed in WO2009 / 131826. A mast mounting structure 52 is provided at one of the stabilizing columns 51 at the corner of the base. The mast mounting structure 52 is configured to mount the mast 2 of the wind turbine 1 onto the mast mounting structure 52. This structure 52 has an upward-pointing mounting axis 53 as its main axis, along which the mast 2 is lowered onto the base 50.

[0135] Using the vessel 200 described below, which is a semi-submersible vessel, said vessel includes:

[0136] -Floating hull 201,

[0137] - 250 cranes are mounted on the hull.

[0138] The crane 250 is equipped with a lifting system 275 suitable for supporting the weight of the wind turbine 1 and suspending the wind turbine 1 on the crane 250. The lifting system is suitable for raising and lowering the wind turbine in a controllable manner.

[0139] The crane 250 and / or its lifting system 275 includes a heave compensation device 300 adapted to compensate for the heave movement of the wind turbine mast 2 relative to the mast mounting structure 52 of the floating base 50 caused by sea conditions.

[0140] For example, a heave compensation device includes one or more motion sensors for monitoring actual heave motion.

[0141] The mast alignment system 400 described below is configured to engage with the suspended wind turbine, specifically with the mast 2 of the suspended wind turbine 1, and to align and maintain the alignment of the wind turbine mast 2 with the mounting axis 53 of the floating base to compensate for movement of the wind turbine mast 2 relative to the mounting axis of the floating base 50 caused by sea conditions, including tilting movements in at least one or more vertical planes.

[0142] Typically, the installation method involves the following steps: the hull of vessel 200 is in a floating state, and the floating base 50 is in a floating state.

[0143] -The wind turbine 1 is suspended on the crane 250 via the lifting system 275.

[0144] - The lower end of the mast 2 of the suspended wind turbine 1 is placed above the mast mounting structure 52 of the floating base 50.

[0145] - Operate the heave compensation device 300 to compensate for the heave motion of the wind turbine mast 2 relative to the mast mounting structure 52 of the floating base 50 caused by sea conditions.

[0146] - Operate the mast alignment system 400 to align and maintain the alignment of the mast 2 of the wind turbine 1 with the mounting axis 53 of the floating base 50, in order to compensate for the tilting movement of the wind turbine mast 2 relative to the mounting axis 53 of the floating base caused by sea conditions.

[0147] When the heave compensation device 300 and the mast alignment system 400 are in operation, the lifting system 275 is operated to lower the suspended wind turbine 1 and the lower end of the mast 2 together onto the mast mounting structure 52 of the floating base 50.

[0148] - Mast mounting structure 52 that secures mast 2 and its lower end to the floating base.

[0149] Preferably, at least the mast alignment system 400 remains operational during some or all of the fastening steps, for example, during which the system 400 is used to or assists in stabilizing the wind turbine relative to the base.

[0150] Preferably, at least the heave compensation device 300 remains operational during part or all of the fastening steps. For example, the device 300 is also used during this step to support at least a portion of the weight of the wind turbine relative to the base, for example to use or assist in gradually transferring the weight of the wind turbine to the base, for example, by ballasting the vessel to compensate for this transfer.

[0151] It can be seen that during the installation of the wind turbine, the floating base is constrained by the restraint system 350 at least or only in the horizontal plane relative to the ship 200.

[0152] As an example, the restraint system for the base involves the use of a clamping device 351 mounted on the vessel, which has a coupling member 352 engaged with the floating base, here engaged with the mast mounting structure of the floating base. The clamping device 351 has an active controlled motion mechanism 353, similar in design to, for example, the mast coupling devices 420, 440, which is configured and operates to provide controlled movement of the coupling member 352 relative to the hull of the vessel 200, thereby achieving controlled restraint of the engaged floating base 50 relative to the hull of the vessel.

[0153] like Figure 1 and Figure 2 As shown, in this example, the assembly of the wind turbine 1 to be installed is envisioned to be completed on the vessel 200. The vessel sails to a wind farm where floating bases already exist, for example, where the vessel anchorage has multiple wind turbines 1 in an unassembled state stored on the vessel.

[0154] For example, at least five major components of a wind turbine are stored separately on the ship, namely the upper mast section 2a, the lower mast section 2b, the nacelle 3, and the rotor blades 4.

[0155] Preferably, multiple floating bases 50 are already anchored in their final positions in the offshore wind farm, none of which have wind turbines 1. The vessel 200 sails to the wind farm and assembles the wind turbines on board in sequence, and then installs the wind turbines on the floating bases 50.

[0156] Preferably, the mast 2 is lowered onto the mast mounting structure 52 so as to establish an initial fastening between the mast and the base, thereby stabilizing the wind turbine relative to the base, for example, enabling the operation of the alignment system 400 to be stopped, or enabling the alignment system to be disengaged.

[0157] The alignment system 400 shown as an example includes an upper mast engagement device 420 and a lower mast engagement device 440, each having mast engagement members 421, 441 and active controlled motion mechanisms 422, 442 configured and operated to provide controlled movement of the mast engagement members in the horizontal plane.

[0158] The mast coupling devices 420 and 440 act on the mast 2 at different heights. For example, the lower one is below the center of gravity G of the wind turbine 1 to be installed, while the higher one is above the center of gravity G.

[0159] The active controlled motion mechanisms 422 and 442 are configured and operated to align and maintain the alignment of the mast 2 of the suspended wind turbine 1 with the mounting axis 53 of the floating base 50 at relevant moments during the installation process.

[0160] For example in Figures 13a-13c The diagram shows that each active controlled horizontal motion mechanism 422, 442 includes a first set of one or more horizontal tracks 422a extending in a first horizontal direction, the first set of one or more horizontal tracks 422a supporting at least one first carrier 422b1, 422b2, and the one or more first carriers supporting a second set of one or more horizontal tracks 422c1, 422c2 extending in a second horizontal direction different from the first direction, for example, the first direction and the second direction are orthogonal, the second set of one or more horizontal tracks supporting one or more additional second carriers 422d1, 422d2, which support mast engagement devices 421, 441.

[0161] Each mast engagement assembly 420, 440 of the alignment system 400 is shown to include trolleys 425, 445 vertically guided along one or more vertical guide rails 426, 446 mounted on a crane 250. Each trolley supports a mast engagement member, and an active controlled motion mechanism is inserted between the trolley and the mast engagement member to provide controlled movement of the mast engagement member in the horizontal plane, for example, in two orthogonal horizontal directions.

[0162] The mast joint member 421 is suspended from the upper part of the crane 250 by a lifting device, and the wind turbine 1 is suspended from the mast joint member 421.

[0163] The crane has a vertical crane structure 260 erected on the hull of the ship. Here, the vertical crane structure has a lower section 261 of the crane structure fixed to the hull and a rotatable top section 262 on a slewing bearing 262a.

[0164] The lifting device includes one or more winch drive cables 276, 277, which hang from pulley blocks 278, 279 arranged on a rotatable top section, here arranged on a fork-shaped pivot arm 265 of the rotatable top section.

[0165] The rotation of the top section 262 can be used to pick up the assembled wind turbine 1 from the deck of the vessel 200 via a lifting device and bring the wind turbine and its mast to the mast mounting structure of the floating base 50.

[0166] As shown in the figure, the rotatable top section 262 of the vertical crane structure is equipped with an upper mast connecting device 420, and the fixed lower section 261 of the vertical crane structure is equipped with a lower mast connecting device 440.

[0167] Now refer to Figure 15 , Figure 16a , Figure 16b The installation of the wind turbine on the floating base 50' is described in detail. As shown, the lower mast section 2b has been installed on the base 50', for example during the production of the base 50' or at sea, for example using the vessel 200' used to complete the wind turbine or another offshore vessel, such as a vessel equipped with a general-purpose heavy-duty crane.

[0168] Figure 15 , Figure 16a , Figure 16b The pre-assembled assembly of the upper mast section 2a, engine room 3, and rotor blades 4 is shown being handled as a sub-assembly or unit by the crane 250' of the ship 200' for placing the unit on top of the lower mast 2b. Alternatively, the crane structure of the crane 250 is shown configured to handle two such assemblies simultaneously. Here, Figure 15 The left-hand component is supported in the operating position above the lower mast section 2b, which is already installed on the floating base 50', while the right-hand component is supported in the transport position at a height lower than the operating position due to the stability of the ship.

[0169] For example, a method for installing a wind turbine can be performed using vessel 200', wherein the method includes the following steps, with the hull of vessel 200' and base 50' in a floating state:

[0170] -will be in a lower transportation position ( Figure 15The wind turbine assembly (or multiple wind turbine assemblies) on the right side of the image is transported from the pre-assembly location to the existing installation location at the base 50', such as a wind farm.

[0171] Moving the vessel 200' to a position relative to the base 50' and maintaining the vessel in such a relative position preferably involves the use of restraint devices 350, 351 as described herein.

[0172] -Lifting the wind turbine components from a lower transport position to an elevated operating position ( Figure 15 (on the left side of the base), and place the wind turbine assembly above the lower mast section 2b already installed on the base 50', for example, involving moving the vessel 200' relative to the (moored) base 50'.

[0173] As from Figure 16a , Figure 16b The method further comprises aligning and maintaining the alignment of the upper mast section 2a with the lower mast section 2a (at a certain distance above the tip of the lower mast section) due to the operation of two active horizontal movement devices 420, 440 engaged on the sub-assembly to be installed, in order to compensate for motion caused by sea conditions, such as tilting motion of the base and / or the vessel due to the sea conditions shown. It is considered that the sub-assembly is preferably engaged by the two devices 420, 440 because balancing only this assembly is actually more difficult than balancing a wind turbine including the full-length mast. For example, there is a vertical spacing of at least 20 meters between the devices 420, 440 engaged on the sub-assembly.

[0174] Crane 250' is preferably also equipped with a related heave compensation device to compensate for the vertical movement of the lower end of the upper mast section 2a relative to the lower mast section 2b mounted on the floating base caused by sea conditions.

[0175] Figure 16b Two active horizontal movement devices 420, 440 are shown operating to maintain the alignment of the mast section before and during (at least in the first phase) the assembly descends to the top of the lower mast section 2b.

[0176] In a preferred embodiment, the vessel 200' is stabilized by appropriately operating one or more damping devices, such as roll and / or pitch motion damping devices. For example, the vessel 200' is equipped with a roll damping device comprising one or more movable solid pressure vessels guided on tracks on the hull, and associated displacement actuators and displacement drive controllers, the drive controllers being adapted to induce movement of the one or more solid pressure vessels to compensate for roll motion caused by sea conditions. For example, the vessel further includes at least one pitch damping device comprising one or more movable solid pressure vessels guided on tracks, and associated displacement actuators and displacement drive controllers, the drive controllers being adapted to induce movement of the one or more solid pressure vessels to compensate for pitch motion caused by sea conditions.

Claims

1. A method for mounting a wind turbine on a floating base (50, 50'), the floating base being in a floating state and subject to motion caused by sea conditions, in, The wind turbine to be installed includes at least a portion of a wind turbine mast (2, 2a, 2b) having a lower end, and includes a rotor assembly having rotor blades (4) mounted on the wind turbine mast. The floating base includes a mast mounting structure configured to mount the mast of the wind turbine onto the mast mounting structure, and the mast mounting structure has an upward-pointing mounting axis. Among them, the following vessels (200, 200') are used, and the vessels include: - Floating hull (201). - Cranes (250, 250') are mounted on the hull. The crane is equipped with a lifting system suitable for supporting the weight of the wind turbine and suspending it on the crane. This lifting system is adapted to raise and lower the wind turbine in a controlled manner. The crane includes a heave compensation device adapted to compensate for the heave motion of the wind turbine mast relative to the mast mounting structure of the floating base caused by sea conditions. The vessel includes a mast alignment system (420, 440) configured to engage with the mast of the suspended wind turbine and to align and maintain alignment between the wind turbine mast and the mounting axis of the floating base, compensating for movement of the wind turbine mast relative to the mounting axis of the floating base caused by sea conditions, including tilting movements in at least one or more vertical planes. The method includes the following steps—when the ship's hull is floating and the floating base is floating: - The floating base is constrained in the horizontal plane relative to the ship by a restraint system. - The wind turbine is suspended on a crane using a lifting system. - The lower end of the mast of the suspended wind turbine is positioned above the mast mounting structure of the floating base. - Operate the heave compensation device to compensate for the heave motion of the wind turbine mast relative to the mast mounting structure of the floating base caused by sea conditions. - Operate the mast alignment system (420, 440) to align and maintain alignment of the wind turbine mast with the mounting axis of the floating base, compensating for tilting motion of the wind turbine mast relative to the mounting axis of the floating base caused by sea conditions. - When the heave compensation device and mast alignment system are in operation, operate the lifting system to lower the suspended wind turbine and the lower end of the mast together onto the mast mounting structure of the floating base. - A mast mounting structure that secures the mast and its lower end to the floating base.

2. The method according to claim 1, wherein, The mast alignment system is also configured to compensate for horizontal movement of the wind turbine mast relative to the mounting axis of the floating base caused by sea conditions in at least one horizontal direction.

3. The method according to claim 1, wherein, Multiple floating bases (50, 50') are anchored in their final positions in the offshore wind farm, none of which have wind turbines, and the ship sails to the wind farm and installs the wind turbines on the floating bases in sequence.

4. The method according to claim 1, wherein, The mast is lowered onto the mast mounting structure so that, or subsequently, an initial fastening is established between the mast and the floating base, stabilizing the wind turbine relative to the floating base, enabling the operation of the alignment system to be stopped, and enabling the system to be disengaged.

5. The method according to claim 1, wherein, At least the mast alignment system (420, 440) remains operational during some or all of the fastening steps, and the mast alignment system is used or assists in stabilizing the wind turbine relative to the base during the fastening steps.

6. The method according to claim 1, wherein, At least the heave compensation device remains operational during some or all of the fastening steps, and the heave compensation device is also used or assists in supporting at least a portion of the weight of the wind turbine relative to the base during the fastening steps.

7. The method according to claim 1, wherein, The restraint system includes multiple mooring lines extending in different directions and arranged between the floating base and the hull of the vessel, so as to provide a connection between the floating base and the hull, at least or only in the horizontal plane.

8. The method according to claim 1, wherein, The restraint system includes a clamping device (351) mounted on the vessel, the clamping device having an engaging member engaged on a floating base, and the clamping device having an active controlled motion mechanism configured and operated to provide controlled movement of the engaging member relative to the hull of the vessel, thereby achieving controlled restraint of the engaged floating base relative to the hull of the vessel.

9. The method according to claim 1, wherein, The alignment system includes at least one mast engagement device (420, 440) having a mast engagement member and an active controlled motion mechanism configured and operated to provide controlled movement of the mast engagement member in the horizontal plane so as to align and maintain alignment of the mast of the suspended wind turbine with the mounting axis of the floating base.

10. The method according to claim 1, wherein, The alignment system includes an upper mast engagement device (420) and a lower mast engagement device (440), each of which has a mast engagement member and an active controlled motion mechanism configured and operated to provide controlled movement of the mast engagement member in the horizontal plane, wherein the mast engagement device acts on the mast at different heights, and wherein the active controlled motion mechanism is operated to align and maintain alignment of the mast of the suspended wind turbine with the mounting axis of the floating base.

11. The method according to claim 9, wherein, Each active controlled horizontal motion mechanism includes a first set of one or more horizontal rails extending in a first horizontal direction, the first set of one or more horizontal rails supporting at least one first carrier, and the at least one first carrier supporting a second set of one or more horizontal rails extending in a second horizontal direction different from the first direction, the second set of one or more horizontal rails supporting one or more additional second carriers, the second carriers supporting the mast engagement device.

12. The method according to claim 9, wherein, Each mast engagement device (420, 440) of the alignment system includes a trolley supporting a mast engagement member along one or more vertical guide rails, and an active controlled motion mechanism inserted between the trolley and the mast engagement member to provide controlled movement of the mast engagement member in the horizontal plane.

13. The method according to claim 1, wherein, The alignment system includes an upper mast engagement device (420) comprising a trolley vertically guided along one or more vertical guide rails, the trolley supporting a mast engagement member, an active controlled motion mechanism inserted between the trolley and the mast engagement member to provide controlled movement of the mast engagement member in a horizontal plane, wherein a wind turbine is suspended from the mast engagement member, and wherein the mast engagement member is suspended from a crane by a lifting device.

14. The method according to claim 1, wherein, The crane is provided with a first upper pulley group and a second upper pulley group that are horizontally spaced apart, and the mast joint is provided with a first lower pulley group and a second lower pulley group that are horizontally spaced apart, wherein a first multi-rope cable device (276) extends between the first upper pulley group and the first lower pulley group, and a second multi-rope cable device (277) extends between the second upper pulley group and the second lower pulley group, and wherein the mast (2) is suspended on the mast joint.

15. The method according to claim 1, wherein, The crane has a vertical crane structure erected on the hull of a ship, wherein the vertical crane structure has a lower section of the crane structure fixed to the hull and a rotatable top section, wherein the lifting device includes one or more winch drive cables hanging from one or more pulley blocks arranged in the rotatable top section, wherein the rotation of the top section is used to pick up the assembled wind turbine from the deck of the ship via the lifting device and bring the wind turbine with a mast to above the mast mounting structure of the floating base.

16. The method according to claim 15, wherein, The alignment system is installed on the vertical crane structure of the crane, and the rotatable top section of the vertical crane structure is provided with an upper mast engagement device, and the fixed lower section of the vertical crane structure is provided with a lower mast engagement device.

17. The method according to claim 1, wherein, The vessel is a semi-submersible vessel with a pair of substantially parallel, laterally spaced buoyancy pontoons and a row of columns supported by each pontoon and extending upward from each pontoon, as well as a deck structure supported by the upper ends of the columns, wherein a crane is mounted on the deck structure of the hull.

18. The method according to claim 17, wherein, Viewed from above, the floating base has a stabilizing column at its corner, on which the wind turbine will be mounted, and in which a semi-submersible vessel and pontoons are arranged on opposite sides of the stabilizing column, and in which a crane suspends the mast of the wind turbine above the mast mounting structure on the stabilizing column.

19. The method according to claim 1, wherein, One or more sensors are used to monitor the movement of the mast mounting structure relative to the lower end of the mast floating base in one or more directions during installation, wherein the one or more sensors are linked to a computerized controller configured and operated to cause the automatic operation of the mast alignment system.

20. The method according to claim 1, wherein, The assembly of the wind turbines to be installed is completed on the ship, which sails to the wind farm where there are already floating bases. The ship has multiple wind turbines in an unassembled state stored on the ship, with the masts, nacelles and rotor blades of at least 5 wind turbines stored separately on the ship.

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