Method for positioning and aligning mega-blocks of semi-submersible floater for offshore wind turbine

Abstract

The invention relates to a method for positioning and aligning mega-blocks of a semi-submersible floater (2) for an offshore wind turbine, the floater consisting of the assembly of at least two different individual mega-blocks, the method comprising: positioning of each individual mega-block on a plurality of positioning systems (30) each comprising a platform (32) on which the mega-block of the floater is intended to rest and which is mounted on a controlled mechanism for horizontal and vertical translation; and coordinated adjustment of the platforms of the positioning systems by measuring the positioning and controlling the positioning systems associated with each individual mega-block as a function of a target block in order to position and align the individual mega-blocks with respect to one another.

Description

Description Title of the invention: Method for positioning and aligning semi-submersible float mega-blocks for offshore wind turbines Technical Field

[0001] The invention relates to the general field of mass production of floats for offshore wind turbines. More specifically, it relates to a method for positioning and aligning unitary mega-blocks forming such floats. Prior art

[0002] An offshore wind turbine uses wind energy to generate electricity using a turbine and an electric generator. There are two main types of offshore wind turbines: fixed wind turbines, which are installed on the seabed (at shallow depths, typically less than 50m), and floating wind turbines, which offer the advantage of being able to be built on land and installed in areas where the seabed depth typically exceeds 50m.

[0003] The floating wind turbines to which the present invention relates comprise a turbine generally formed by a motor with several horizontal-axis rotating blades and an electric generator coupled to the motor, the motor and generator being fixed to an upper end of a vertical mast (or pylon).

[0004] The lower end of the mast is mounted on a floating support structure (called a "float"). There are different types of floats, namely semi-submersible floats (with or without pendulum counterweight), submerged floats with tensioned cables (or "TLP" platforms for "Tension-Leg Platform" in English), "SPAR" type floats (for "Single Point Anchor Reservoir"), semi-submersible "barge" type floats, etc. For example, we can refer to the publication WO 2019 / 106283 which describes a floating support structure whose main structure has a toroidal or polygonal shape.

[0005] Offshore wind turbines are most often grouped together in a "wind park" or "wind farm" generally comprising between 20 and 50 wind turbines with a unit power of several megawatts.

[0006] In floating offshore wind farm development projects, the floater delivery schedule is a key parameter for the successful delivery of large offshore wind farms within tight installation windows. Furthermore, the ability to secure local floater production is of utmost importance, but land space available for floater assembly is usually a major obstacle.

[0007] Patent application FR 23 02023 filed on March 3, 2023 discloses a method for the mass production of floats for offshore wind turbines, each consisting of the assembly of at least two different unitary mega-blocks of floats. This method is remarkable in that it allows floats for offshore wind turbines to be manufactured in series on a very limited land area.

[0008] Implementing such a production process poses a number of technical problems, in particular that of having to position the mega-blocks of floats with great precision to enable their assembly. Statement of the invention

[0009] The invention therefore aims to propose a method for positioning and aligning semi-submersible float mega-blocks making it possible to address this problem.

[0010] According to the invention, this aim is achieved by means of a method for positioning and aligning semi-submersible float mega-blocks for offshore wind turbines, the float being constituted by the assembly of at least two different unit mega-blocks, the method comprising: - the positioning of each unitary mega-block on a plurality of positioning systems each comprising a platform on which the float mega-block is intended to rest and which is mounted on a controlled horizontal and vertical translation mechanism, and - the coordinated adjustment of the platforms of the positioning systems by measuring the positioning and controlling the positioning systems associated with each unit mega-block according to a target block in order to position and align the unit mega-blocks relative to each other.

[0011] The method according to the invention is remarkable in that it uses a plurality of positioning systems on which the unitary mega-blocks rest and which are controlled in a coordinated manner in order to adjust the mega-blocks relative to each other during the various stages of manufacturing the floats. This positioning process is thus carried out automatically with a minimum of human intervention.

[0012] Positioning systems can be measured using a surveying device. Positioning systems can also be measured and controlled remotely using wired or wireless methods.

[0013] The invention also relates to a positioning system for implementing the method as defined above, comprising a platform on which the float mega-block is intended to rest and which is mounted on a horizontal and vertical translation mechanism.

[0014] The invention also relates to a method for the mass production of semi-submersible floats for offshore wind turbines, each consisting of the assembly of two to six individual steel mega-blocks, the method successively comprising the manufacture of a plurality of steel mega-blocks on a dedicated construction surface provided with a loading dock; - the transport by sea of ​​mega-blocks from the construction area and their storage in different storage areas of a production area separate from the construction area and equipped with an unloading dock, the same mega-blocks of floats being stored in the same storage area of ​​the production area; - the final production line of floats comprising successively for each float, a step of preparing the mega-blocks at their storage area, a step of assembling and primary welding the float mega-blocks together at an assembly and primary welding area separate from the storage areas and adjacent to them, followed by a step of final welding of the mega-blocks together at a final welding area separate from the other areas of the production area, followed by a step of completing the float at a completion area separate from the other areas of the production area; - the mega-blocks of floats and the floats being manufactured being moved on the production surface between the different zones thereof mainly according to translational movements; and - the float mega-blocks and the floats being manufactured being positioned and aligned in the primary assembly and welding, final welding, and completion areas using the process as defined above.

[0015] The positioning systems are advantageously sized to elevate the mega-float blocks and floats being manufactured to allow the passage of multi-wheeled transport vehicles.

[0016] Each float may be formed by assembling three mega-blocks: a first mega-block comprising a central column, an outer column and a lower pontoon, and two second identical mega-blocks each comprising an outer column and a lower pontoon, in which case, at the primary assembly and welding area, the first mega-block is static and constitutes a target block and the positioning of the second two mega-blocks is adjusted according to the position of the first mega-block.

[0017] Each float mega-block can be positioned in the primary assembly and welding, final welding, and completion areas by means of two parallel rows of positioning systems. Brief description of the drawings

[0018] [Fig. 1] Figure 1 is a schematic and perspective view of an example of an installation for implementing the positioning method according to the invention.

[0019] [Fig. 2] Figure 2 is a top view of a float in the process of being manufactured showing the positioning systems according to the invention.

[0020] [Fig. 3] Figure 3 is a perspective view of an exemplary positioning system according to the invention.

[0021] [Fig. 4A-4D] Figures 4A to 4D show the different possible displacements of the platform of the positioning system of Figure 3. Description of the embodiments

[0022] The invention relates to the general field of mass production and the chain of floats for offshore wind turbines, in particular semi-submersible type floats.

[0023] The floats to which the present invention applies have the particularity of being able to be manufactured by assembling two to six individual steel mega-blocks.

[0024] In the application example described below, each float 2 comprises, as shown in Figures 1 and 2, four columns including a central column 4 which is intended to receive a wind turbine mast and three external columns 6 which are connected to the central column by lower pontoons 8.

[0025] In practice, such floats 2 can each be formed by assembling three mega-blocks: a first mega-block Bl comprising the central column 4, an outer column 6 and a lower pontoon 8, and two second identical mega-blocks B-2 each comprising an outer column 6 and a lower pontoon 8.

[0026] Of course, the invention applies to other types and other forms of floats, the latter having to be formed by the assembly of two to six unitary steel megablocks.

[0027] The preliminary step in the mass production process of such floats consists of manufacturing the various mega-blocks Bl, B-2 then required for the production of the floats. This manufacturing is carried out on a dedicated construction surface (not shown in the figures) which is equipped with a loading dock and which is separate (and can be remote) from the production surface on which the floats are produced. This mass production of mega-blocks consists of assembling and welding steel sheets to form the various unit mega-blocks required for the manufacture of the floats.

[0028] The mass production process for the floats requires a land-based production area 10 capable of accommodating the various components and equipment required for the manufacture of the floats. This production area 10 is separate from the construction area on which the steel mega-blocks are manufactured.

[0029] As shown in Figure 1, this production area 10 is divided into different zones Z1 to Z6, namely: a first storage zone Z1 on which the mega-blocks B1 are stored, a second storage zone Z-2 on which the mega-blocks B-2 are stored, an assembly and primary welding zone Z-3 on which the different mega-blocks B1, B-2 constituting the same float are assembled together and subjected to primary welding, a final welding zone Z-4 ​​on which the different mega-blocks constituting the float undergo a new welding pass, a completion zone Z-5 on which the float is inspected and equipped with various equipment, and a zone Z-6 buffer on which a 2' float with manufacturing defects can be removed for repair.

[0030] A transport barge 20 is moored at the loading dock of the production area. Float 2 located in the Z-5 completion zone is then loaded onto the transport barge by means of transport.

[0031] It should be noted that the mega-float blocks and floats being manufactured are moved between the different areas of the construction surface by multi-wheeled transport vehicles or by skidding, i.e. mainly following translational movements.

[0032] At the level of the assembly and primary welding zones Z-3, final welding Z-4, and completion Z-5, the mega-blocks Bl, B-2 and the floats being manufactured are positioned and aligned by means of a method according to the invention illustrated in particular by figure 2.

[0033] According to this positioning and alignment method, each block B1, B-2 is positioned at these areas on a plurality of positioning systems 30.

[0034] As shown in Figure 3, each positioning system 30 comprises in particular a platform 32 on which the float mega-block is intended to rest and which is mounted on a controlled mechanism 34 for horizontal and vertical translation.

[0035] More precisely, the controlled mechanism 34 (for example with hydraulic or mechanical jacks) makes it possible to move the platform 32 in the two horizontal directions X, Y and the vertical direction Z. Figures 4A to 4D illustrate, in side view, these movements of the platform 32 in the directions X and Z.

[0036] It should be noted that the controlled mechanism 34 is sized to allow the platform to take the full weight of the mega-float block (typically greater than 100 tonnes).

[0037] It will also be noted that the positioning systems 30 are arranged on fixed foundations 36 forming supports. These foundations 36 allow to avoid collisions with multi-wheeled transport vehicles during transfers of float mega-blocks. They also help to minimize deformation and stress on float mega-blocks during assembly phases. They also help to minimize the bearing pressure on the floor of the production area.

[0038] Furthermore, the platforms 32 of the different positioning systems 30 on which the same float mega-block B1, B-2 are positioned are adjusted relative to each other in order to position and align the blocks relative to each other for the purpose of their assembly and welding.

[0039] More specifically, at the Z-3 primary assembly and welding area, a first float mega-block is brought in and positioned on positioning systems. This first float mega-block acts as a target block.

[0040] The other two float mega-blocks are then brought and positioned on positioning systems. The platforms of these systems are adjusted in a coordinated manner to position and align the two mega-blocks in relation to the target block in particular.

[0041] This adjustment can be carried out within a minimum time constraint (typically less than 10 minutes) and with precision of the order of a millimeter to allow the execution of butt joining and welding operations.

[0042] Additionally, adjustment is coordinated between the different positioning systems by measuring the positioning and controlling the positioning systems associated with each float mega-block based on the target block.

[0043] As shown in Figure 2, the measurement of the positioning of the different positioning systems 30 can be carried out by topographic devices 38 (laser, scanner, theodolite, etc. type) located angularly between the branches of the float. These topographic devices 38 are connected to the control mechanisms of the positioning systems 30 to send them the appropriate control orders.

[0044] The transmission of instructions between the topographic devices 38 and the control mechanisms of the positioning systems 30 can be wired or wireless (for example remotely by waves).

[0045] Thus, the invention consists of a system that controls all the degrees of freedom of the mega-block being installed by using buffers with a capacity of 300 tons for each of them, driven by electric motors controlling the displacement (with a stroke of + / - 150 mm) in the three directions of space. The point of contact between the structure of the mega-block and each buffer is made by a hemisphere (integrated in the structure of the buffer) allowing rotations around the three axes (with an amplitude of + / - 3°). The movements and rotations of the buffers are then managed by an automaton that ensures the positioning of the mega-block on the required position and orientation with absolute precision.

[0046] The system according to the invention ensures the compensation of the ground displacement once the load of the mega-block is transferred from the multi-wheeled transport vehicles to the positioning systems and eliminates the need to shim with plates of different dimensions and thicknesses the interface between the positioning systems and the mega-blocks to level / align the surfaces to be joined. In addition, the system according to the invention is capable of directly and continuously controlling the gap necessary for welding.

Claims

Claims

1. Method for positioning and aligning semi-submersible float megablocks (2) for offshore wind turbine, the float being constituted by the assembly of at least two different unit megablocks (B1, B-2), the method comprising: - the positioning of each unitary mega-block on a plurality of positioning systems (30) each comprising a platform (32) on which the float mega-block is intended to rest and which is mounted on a controlled mechanism (34) for horizontal and vertical translation, and - the coordinated adjustment of the platforms of the positioning systems by measuring the positioning and controlling the positioning systems associated with each unit mega-block according to a target block in order to position and align the unit mega-blocks relative to each other.

2. A method according to claim 1, wherein the measurement of the positioning of the positioning systems is carried out by a topographical apparatus (38).

3. Method according to one of claims 1 and 2, in which the measurement of the positioning and the control of the positioning systems are carried out in a wired manner.

4. Method according to one of claims 1 and 2, in which the measurement of the positioning and the control of the positioning systems are carried out remotely.

5. Positioning system (30) for implementing the method according to any one of claims 1 to 4, comprising a platform (32) on which the float mega-block (B-1, B-2) is intended to rest and which is mounted on a horizontal and vertical translation mechanism (34).

6. Method for mass production of semi-submersible floats (2) for offshore wind turbines, each consisting of the assembly of two to six unitary mega-blocks (Bl, B-2) made of steel, the method successively comprising: - the manufacture of a plurality of steel mega-blocks on a dedicated construction area equipped with a loading dock; - the transport by sea of mega-blocks (Bl, B-2) coming from the construction area and their storage in different storage areas (Zl, Z-2) of a production area (10) separate from the construction area, the same mega-blocks of floats being stored in the same storage area of the production area; - the final production line of floats comprising successively for each float, a step of preparing the mega-blocks at their storage area, a step of assembling and primary welding the float mega-blocks together at an assembly and primary welding area (Z-3) separate from the storage areas and adjacent to them, followed by a step of final welding of the mega-blocks together at a final welding area (Z-4) separate from the other areas of the production area, followed by a step of completing the float at a completion area (Z-5) separate from the other areas of the production area; - the mega-blocks of floats and the floats being manufactured being moved on the production surface between the different zones thereof mainly according to translational movements; and - the float mega-blocks and floats being manufactured being positioned and aligned in the primary assembly and welding, final welding, and completion areas by means of the method according to any one of claims 1 to 5.

7. The method of claim 6, wherein the positioning systems (30) are sized to elevate the float mega-blocks and floats being manufactured to allow passage of multi-wheeled transport vehicles.

8. Method according to one of claims 6 and 7, in which: - each float is formed by the assembly of three mega-blocks: a first mega-block (Bl) comprising a central column (4), an outer column (6) and a lower pontoon (8), and two second identical mega-blocks (B-2) each comprising an outer column (6) and a lower pontoon (8), and in which - at the primary assembly and welding area, the first mega-block is static and constitutes a target block and the positioning of the second two mega-blocks is adjusted according to the position of the first mega-block.

9. A method according to any one of claims 6 to 8, wherein each float mega-block is positioned in the primary assembly and welding, final welding, and completion areas by means of two parallel rows of positioning systems.

Images