System and method for connecting service vessels and floating support structures

Abstract

The present invention describes a system and method for connecting a service vessel (1) and a floating support structure (2) for a wind turbine (3). The service vessel comprises a stern coupling section (5) and a ship contact means (6) located on the stern coupling section (5), which can be raised up and down between a higher contact position and a lower free position by a lifting means. The floating support structure (2) comprises a central coupling space (7) capable of receiving the stern coupling section (5) and a support structure contact means (8) for interacting with the ship contact means (6) when the stern coupling section (5) is positioned in the center of the coupling space (7) and the ship contact means (6) is moved upward. The ship contact means (6) is positioned at a height below the support structure contact means (8) when the ship contact means (6) is in the lower free position.

Description

Technical Field

[0001] The present invention relates to offshore wind energy, and more particularly to a system for coupling service vessels to a floating support structure and enabling them to be moved as one structure.

Background Art

[0002] Offshore winds are a growing energy source that will be part of the future energy mix. Since it is a remote location relative to suitable onshore locations for maintenance and repair, it is desirable to be able to perform all maintenance and repairs at an offshore location, eliminating the need to remove the floating body to tow it to the shore. In the prior art, important maintenance work has been solved by disconnecting the connection between the floating body assembly and the wind turbine and towing it to the port. This is a costly and very time-consuming solution, which will involve the removal of both the anchoring system and the electrical cable before towing the wind turbine to an onshore location.

[0003] Fred Olsen 1848 AS solves the important maintenance problem simply by attaching a crane on the support structure of the wind turbine. This takes time and requires a support structure designed to suit the purpose, as shown in its homepage: Non-Patent Document 1. Fred Olsen also describes an alternative solution in its homepage: Non-Patent Document 2. Here, a jack-up barge has its base in contact with the pontoon of the floating structure of the wind turbine, lifting the barge above the water to eliminate the relative movement between the barge and the floating structure. The problems with this solution are that the pontoon needs to be strengthened and the jack-up process takes a long time.

[0004] Critical maintenance work may require large, critical components such as gearboxes and even complete RNA (Rotor Nacelle Assembly). Providing the necessary lifting capacity in areas where jack-up vessels cannot be used due to water depth is a challenge. In addition, the relative movement between the crane and the floating support structure complicates crane operations. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] https: / / www.fredolsen1848.com / technologies / floating-maintenance-solution / [Non-Patent Document 2] https: / / www.fredolsen1848.com / news / fred-olsen-1848-is-developing-a-complete-om-solution-and-operational-procedure-for-major-component-exchange-that-is-optimized-for-the-floating-foundation-brunel / [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide a system and method for connecting a service vessel and a wind turbine structure in deep water, enabling the service vessel to perform all service operations on-site. [Means for solving the problem]

[0007] One aspect of the present invention describes a system for connecting a service vessel to a floating support structure for a wind turbine. The service vessel comprises a stern coupling section, a ship contact means located on the stern coupling section, and a lifting means coupled to the ship contact means at one end and to the deck of the service vessel at the other end. The ship contact means and the lifting means are configured to move the ship contact means up and down between a higher contact position and a lower free position. The floating support structure comprises a central coupling space capable of receiving the stern coupling section of the service vessel, and a support structure contact means positioned above the coupling space such that the stern coupling section is centered in the coupling space and the ship contact means moves upward to interact with the ship contact means. The ship contact means is positioned at a lower height than the support structure contact means when the ship contact means is in the lower free position, and the ship contact means contacts the support structure contact means before reaching the higher contact position.

[0008] In embodiments of the present invention, the support structure contact means comprises a reinforced section, and the ship contact means comprises a support fender configured to receive the reinforced section.

[0009] In a further embodiment of the present invention, the support structure contact means comprises a reinforced section, and the ship contact means comprises a crib configured to receive the reinforced section thereon.

[0010] In a further embodiment of the present invention, the lifting means comprises a ballast tank located above the waterline having a large outlet hatch for rapid deballasting, and a ballast tank located below the waterline having a large intake hatch for rapid ballast intake.

[0011] In a further embodiment of the present invention, the lifting means comprises one or more lifting tables having ship contact means located at the top.

[0012] In a further embodiment of the present invention, the ship contact means contacts the support structure contact means at at least three positions, and the line between the at least three positions encloses the gravity point (G).

[0013] In a further embodiment of the present invention, the support structure comprises two transverse floating forward units connected to each other by a horizontal transverse section, the horizontal transverse section having an intermediate point on the waterline connecting the two transverse floating forward units, a stern longitudinal section, and a stern floating unit connected to the intermediate point on the waterline by the stern longitudinal section, thus forming a central coupling space between the floating units and the stern floating unit.

[0014] The support structure may comprise three main sections, each of which comprises a horizontal section above the waterline and a vertical section directly or indirectly connected to each horizontal section and oriented in a common vertical plane with respect to each horizontal section. The vertical sections can provide buoyancy to the floating support structure. The support structure may further comprise a transition piece for joining the three main sections to a central region. The joining space may be located below the three horizontal sections and between the vertical sections.

[0015] In a further embodiment of the present invention, the system further comprises a wind turbine connected to the top of a floating support structure, wherein the gravity point (G) of the combined structure of the wind turbine and support structure is located perpendicular to the centerline (L) of the central coupling space.

[0016] In another aspect of the present invention, a method for connecting a service vessel and a floating support structure for a wind turbine using the system described above is described. The method is: A: The step of positioning the ship contact means at a lower, freer position, B: operating the stern connection section of the service vessel into the central connection space of the floating support structure to a position where the vessel contact means can interact with the support structure contact means; C: raising the vessel contact means to a higher contact position for interacting with the support structure contact means; comprising.

[0017] In an embodiment of the present invention, step C includes further lifting the vessel contact means so that a part of the weight of the floating support structure can be placed on the vessel contact means.

[0018] In an embodiment of the present invention, step B includes using a dynamic positioning system to accurately operate the stern connection section 5 of the vessel into the central connection space 7 of the support structure.

[0019] The following drawings are attached to facilitate understanding of the present invention. The drawings show embodiments of the present invention described only as examples, and the same reference numerals in different drawings indicate the same features.

Brief Description of the Drawings

[0020] [Figure 1a] A diagram showing an embodiment of a service vessel and a floating support structure connected together. [Figure 1b] A diagram showing an alternative embodiment of a service vessel and a floating support structure connected together. [Figure 2] A diagram showing an embodiment of a service vessel. [Figure 3a] A diagram showing an embodiment of a floating support structure including a connection space viewed from above. [Figure 3b] A diagram showing an embodiment of a floating support structure including a connection space viewed from the front. [Figure 3c] A diagram showing an alternative embodiment of a floating support structure including a related connection space viewed from above. [Figure 3d]FIG. showing an alternative embodiment of a floating support structure including the associated coupling space seen from the front. [Figure 4a] FIG. showing a service vessel and an embodiment of a floating support structure arranged in a row for coupling. [Figure 4b] FIG. showing a service vessel and an alternative embodiment of a floating support structure arranged in a row for coupling. [Figure 5] FIG. showing an embodiment of lifting means with a lifting table. [Figure 6] FIG. showing an embodiment of lifting means with a hydraulic piston. [Figure 7] FIG. showing an embodiment of ship contact means with a support fender and a damping cushion. [Figure 8] FIG. showing an embodiment of ship contact means with a platform and lifting means in the form of ballast tanks. [Figure 9] FIG. showing an embodiment of lifting means with a pair of lifting arms connected at their upper ends. [Figure 10] FIG. showing a wire connection and wires for strengthening the connection between the floating support structure and the service vessel.

BEST MODE FOR CARRYING OUT THE INVENTION

[0021] The present invention describes a system for connecting a service vessel 1 and a floating support structure 2 for a wind turbine 3, as shown in FIGS. 1a and 1b. The system is intended to integrate the service vessel and the floating support structure into one structure against the movements caused by wind and waves. The first contact between the service vessel and the floating support structure still requires a period of favorable weather, but the present invention enables important maintenance work to be carried out once the connection is made. The additional weight obtained by the combined structure, as well as the additional width and length, can also stabilize the combined structure.

[0022] The system comprises a service vessel 1 and a floating structure 2 for a wind turbine. An embodiment of the service vessel 1 is shown in Figure 2, and two alternative embodiments of the floating support structure 2 are shown in Figures 3a and 3b, and 3c and 3d, respectively. The service vessel includes a stern coupling section 5 configured to interact with the central coupling space 7 of the floating support structure 2. As shown in Figures 4a and 4b, the service vessel moves into the coupling space 7 and then lifts the floating structure with sufficient force to remain in stable contact with the floating structure in prevailing weather conditions. Lifting can be done in many different ways, several examples of which are described in this document. In most embodiments, the stern coupling section 5 is the stern portion of the service vessel 1.

[0023] The stern coupling section 5 of the service vessel 1 is equipped with a ship contact means 6 located on the stern coupling section, as shown in Figure 2. The ship contact means directly or indirectly contacts the lifting means 10, which can move the ship contact means 6 up and down between a higher contact position and a lower free position. The lifting means 10 can automatically compensate to suppress relative movement between the floating support structure and the service vessel during connection. As can be seen in Figure 2, it is preferable that large lateral fenders 29a and aft fenders 29b are positioned laterally and aft of the service vessel, respectively.

[0024] In advantageous embodiments, the service vessel is equipped with a dynamic positioning system (DP system) to facilitate the maneuver of the service vessel into the coupling space. The DP system may be based on positioning points connected to a floating support structure or on GPS signals. Many such systems are commercially available and will not be described in further detail.

[0025] The central coupling space 7 of the service vessel 1 is configured to receive the stern coupling section 5 of the service vessel 1, as shown in Figures 3a to 3d. For this purpose, the support structure contact means 8, shown in Figure 5, is positioned on the upper side 9 of the coupling space 7 to interact with the ship contact means 6 when the stern coupling section 5 is centrally located in the coupling space 7 and the ship contact means 6 is moved upward toward a higher contact position. In some embodiments, the support structure contact means 8 is simply the upper side of the coupling space 7, and it may be reinforced to handle the weight of the floating support structure that rests on the ship contact means.

[0026] The height above sea level of the different interaction functions in the ship and the floating support structure 2 is of great importance. The ship contact means 6 of the service vessel 1 must be positioned at a height below the support structure contact means 8 when the ship contact means 6 is in a lower, free position. This height difference also needs to allow for some wave action when the stern contact section 5 enters the coupling space 7. When the lifting means 10 is activated, the ship contact means 6 must be able to contact the support structure contact means 8 before reaching a higher contact position.

[0027] Generally, the coupling space 7 extends to a depth less than the deepest draft of the service vessel 1, and is free of obstructions in the space between the water surface and the contact means.

[0028] After contact is made between the ship contact means 6 and the support structure contact means 8, the lifting means must continue its upward movement until sufficient weight is transferred from the buoyant portion of the floating structure 2 to the support ship 1. When the given weight is transferred to the service ship 1, the combined structure of the service ship and the floating support structure will behave as a single unit, as long as forces from waves, wind, and other external sources remain below a threshold determined primarily by the given weight and properties of the ship contact means 6 and the support structure contact means 8. Generally, transferring more weight to the support ship allows the combined structure to withstand stronger forces from larger waves and stronger winds.

[0029] Transferring weight from the floating support structure 2 to the service vessel 1 will result in a change in the distribution of forces acting on the floating support structure. In some embodiments, the support structure contact means 8 includes a reinforced section 27, as shown in Figures 4 and 5. Embodiments of the vessel contact means shown in Figures 5 and 7 include a support fender 11 configured to receive the reinforced section 27 of the support structure contact means 8. The support fender 11 may have a shape that conforms to the shape of the floating support structure, for example, a rounded recess that conforms to the tubular shape of the floating support structure. Embodiments shown in Figure 5 also show damping cushions 15 on each side of the support fender, which may have an inflatable function. The damping cushions 15 will provide a damping effect by first contacting the support structure contact means when the action of the waves causes the vessel contact means to collide with the floating support structure before stable contact is established.

[0030] In the embodiment shown in Figure 8, the ship contact means 6 includes a support base 12 configured to receive a reinforced section 27 of the support structure contact means.

[0031] The lifting means 10 can have many embodiments, and in the embodiment shown in Figure 8, the lifting means 10 comprises a high ballast tank 19 located above the waterline with a large outlet hatch for rapid deballasting, and a low ballast tank 28 located below the waterline with a large intake hatch for rapid ballast intake.

[0032] In the embodiment shown in Figure 5, the lifting means 10 comprises one or more lifting tables 13 having ship contact means 6 located at the top. In a preferred embodiment, the lifting means comprises both ballast tanks 19, 28 and lifting tables.

[0033] In the embodiment shown in Figure 6, the lifting means 10 comprises a plurality of hydraulic pistons 16 connected to a support structure contact means 8 in the form of a rigid point connector 18 connected to a rigid point 17 of a hydraulic piston 16. A clear difference from embodiments of the ship contact means 6 representing a support base 12 or support fender 11 is that, in the case of the hydraulic pistons 16 and the rigid point connector 18 interacting with the rigid point 17, it is possible to configure them to maintain contact with the floating support structure even if, in the absence of a hydraulic piston 16 to hold it, an external force such as a wave would lift the support structure away from the stern coupling section.

[0034] To reinforce the connection between the service vessel and the floating support structure, several wires 26 can be attached to the stern coupling section 5 and to wire connectors 25 on the floating support structure, as shown in Figure 10. This can be an option when lifting heavy items from the wind turbine to the service vessel. A nacelle can weigh 800 tons, and if the weight of the nacelle detached from the wind turbine and placed on the service vessel, and the weight transferred from the support structure to the service vessel, is less than 1600 tons, the service vessel will have looser contact with the floating support structure. Obviously, such work can only be done in clear weather and will probably require a limited period of good weather, but this is acceptable even if it is a limited period of good weather, compared to detaching the wind turbine from the anchor and electrical cables, waiting a week, and then towing the wind turbine onto land.

[0035] In one embodiment, the wire 26 can constitute the lifting means 10. The wire 26 can be fixed to the stern coupling section 5 and the floating support structure 2, and when fixed to the winch, the ship contact means 6 is moved to a higher contact position that provides contact between the ship contact means and the support structure contact means.

[0036] In another embodiment shown in Figure 9, the lifting means comprises a pair of lifting arms 20 connected together at their upper ends, the lower ends of which are raised by a wire system below the deck that operates within a guide track 21 and pulls the lower ends toward each other to raise their upper ends.

[0037] In this embodiment, the ship contact means 6 contacts the support structure contact means 8 at at least three positions, and the line between the at least three positions surrounds the gravity point of the wind turbine and the floating support structure, as shown in Figure 4.

[0038] Figures 3a and 3b show an embodiment of the support structure 2, which comprises two transverse floating forward units 30a and 30b connected to each other in the water by a horizontal transverse section 31. Furthermore, a stern floating unit 32 is connected in the water by a horizontal stern longitudinal section 34 to the midpoint 33 of the horizontal transverse section 31, thus forming a central coupling space 7 between the floating units 30a, 30b, and 32 for receiving the stern coupling section 5 of the service vessel 1. Obviously, other configurations are also possible. Instead of three floating units, there may be four or five, or the floating support structure may be formed as a catamaran, with the coupling space located between the two hulls of the catamaran. However, it should be noted that the tripod type shown in Figures 3a and 3c gives the best rating when evaluating the stability achieved per ton of iron, and the tubular shape of the transverse section and the stern longitudinal section can be lifted by a service vessel without much additional reinforcement.

[0039] The gravity point G of the combined structure of the wind turbine 3 and the support structure 2 is preferably positioned perpendicularly to the centerline L of the coupling space 7, as shown in Figure 3a. Since the mass of the support structure below the contact point has a stabilizing function, it is advantageous for the contact point between the ship and the support structure to be at a high position.

[0040] Figures 3c and 3d show preferred embodiments of the support structure 2 from above and the side. The support structure comprises three main sections 35a, 35b, and 35c, each of which comprises a horizontal section 36 above the waterline and a vertical section 37 directly or indirectly connected to each horizontal section 36 and oriented in a vertical plane common to each horizontal section 36. The vertical sections 37 provide buoyancy to the floating support structure 2. The support structure further comprises a transition piece 15 to connect the three main sections 35a, 35b, and 35c in a central region and to provide a solid base for the wind turbine tower. The connecting space 7 is located below the three horizontal sections 36 and between the vertical sections 37. Preferably, the vertical portions are positioned at each corner of the equidistant triangle, and the joining space comprises an extension of a rectangular cube positioned along the sides of the aforementioned triangle, extending backward in a direction perpendicular to the aforementioned side until it touches the vertical portion (37) on the opposite side of the aforementioned side, as shown in Figure 3c.

[0041] The embodiments shown in Figures 3c and 3d have the advantage that, due to the symmetry of the structure, the gravity point and buoyancy of the support structure coincide with the gravity point of the combined structure, and three alternative coupling spaces are provided, allowing the operator to select the most convenient coupling space according to weather conditions. Furthermore, compared to the embodiments shown in Figures 3a and 3b, it allows the operator to move the crane closer to the tower.

[0042] The present invention also describes a method for connecting a ship and a floating structure for a wind turbine using the above system. The method is as follows: A step of positioning the ship contact means 6 at a lower, freer position, Step B involves maneuvering the stern coupling section of service vessel 1 into the central coupling space 7 of the floating support structure 2 so that the ship contact means 6 can interact with the support structure contact means 8. C. A step of raising the ship contact means 6 to a higher contact position for interaction with the support structure contact means 8, Includes.

[0043] In this embodiment of the method, step C includes the step of further lifting the ship contact means 6 upward so that a portion of the weight of the support structure can be placed on the ship contact means 6.

[0044] In this embodiment, step C may first include raising the lifting table until the ship contact means 6 contacts the support structure means 8, and then emptying the high ballast tank 19.

[0045] Preferably, step B includes using a dynamic positioning system to precisely maneuver the stern coupling section 5 of the ship into the central coupling space 7 of the support structure.

[0046] Preferably, the stern coupling section 5 can be quickly separated from the coupling space 7 in the event of a sudden weather change or other imminent threat. In most embodiments, since the only thing holding the two structures together is the weight of the support structure mounted on the stern coupling section 5, the service vessel can be separated from the floating support structure in minutes by filling the low ballast tank 28. If a locking type connector is used, it should have a release mode to allow for quick release in case of emergency. [Explanation of Symbols]

[0047] 1 service vessel 2 Support structure 3 Wind Turbines 5. Stern coupling section 6 Ship contact means 7. Central Joint Space 8 Support structure contact means 9. Upper side of the central bonding space 10 means of ascending 11 Support fender - High deformation support means 12 Support stand 13 Ascending Table 14 Cranes 15 Damping cushion - Low deformation support means 16 Hydraulic piston 17. Strong point 18 Strong Point Connectors 19 Ballast Tank 20 Lifting Arms 21 Guide Tracks 22 Anchor Line 23 Rotor Blades 24 Nacer 25 Wire Connectors 26 wires 27 Enhanced Sections 28 Low ballast tank 29a Side fender 29b Rear fender 30a Floating unit that crosses the area 30b Transverse floating unit 31 Horizontal cross section 32. Stern floating unit 33 Midpoint of a horizontal cross section 34. Stern longitudinal section 35a main part 35b Main part 35c main part 36 horizontal part 37 Vertical section

Claims

1. A system for connecting a service vessel (1) and a floating support structure (2) for a wind turbine (3), The aforementioned service vessel (1) Stern coupling section (5), A ship contact means (6) located on the stern coupling section (5), A lifting means (10) directly or indirectly connected to the aforementioned ship contact means (6), Equipped with, The ship contact means (6) and the lifting means (10) are configured to move the ship contact means (6) up and down between a higher contact position and a lower free position. The floating support structure (2) is, A central coupling space (7) capable of receiving the stern coupling section (5) of the service vessel (1), The stern coupling section (5) is positioned at the center of the central coupling space (7), and when the ship contact means (6) moves upward, a support structure contact means (8) is positioned above (9) the central coupling space (7) to interact with the ship contact means (6), Equipped with, The ship contact means (6) is positioned at a lower height than the support structure contact means (8) when the ship contact means (6) is in a free position lower than the above. The ship contact means (6) contacts the support structure contact means (8) before reaching the higher contact position.

2. The system according to claim 1, wherein the support structure contact means (8) comprises a reinforced section (27), and the ship contact means (6) comprises a support fender (11) configured to receive the reinforced section (27).

3. The system according to claim 1, wherein the support structure contact means (8) comprises a reinforced section (27), and the ship contact means (6) comprises a support base (12) configured to receive the reinforced section (27) thereon.

4. The aforementioned lifting means (10) A ballast tank (19) located above the waterline has a large outlet hatch for rapid deballasting, A ballast tank (19) located below the water level line has a large intake hatch for rapid ballast intake, A system according to any one of claims 1 to 3, comprising:

5. The system according to any one of claims 1 to 4, wherein the lifting means (10) comprises one or more lifting tables (13) having the ship contact means (6) located at the top.

6. The system according to any one of claims 1 to 5, wherein the ship contact means (6) contacts the support structure contact means (8) at at least three positions, and the line between the at least three positions encloses the gravity point (G).

7. The floating support structure (2) is, Two transverse floating forward units (30a, 30b) connected to each other by a horizontal transverse section (31), wherein the horizontal transverse section (31) connects the two transverse floating forward units (30a, 30b) on the waterline and has an intermediate point (33), The longitudinal section at the stern (34) and On the waterline, a stern floating unit (32) is connected to the midpoint (33) by the stern longitudinal section (34), The system is equipped with such a feature, and therefore the central coupling space (7) is formed between the floating forward unit (30a, 30b) and the stern floating unit (32). The system according to any one of claims 1 to 6, wherein the central coupling space is located below the horizontal transverse section and the stern longitudinal section, and between the two transverse floating forward units and the stern floating unit.

8. The floating support structure (2) is, There are three main sections (35a, 35b, 35c), and each of the three main sections (35a, 35b, 35c) is, The horizontal portion (36) above the water level line, Each of the horizontal portions (36) is directly or indirectly connected to a vertical portion (37) which is oriented within a common vertical plane with respect to each of the horizontal portions (36), Equipped with, The vertical portion (37) comprises three main sections (35a, 35b, 35c) that provide buoyancy to the floating support structure (1), In the central region, a transition piece (15) for connecting the three main sections (35a, 35b, 35c), Equipped with, The system according to any one of claims 1 to 6, wherein the central coupling space (7) is located below the three horizontal portions (36) and between the vertical portions (37).

9. The system according to any one of claims 1 to 8, further comprising a wind turbine (3) connected to the upper part of the floating support structure, wherein the gravity point (G) of the combined structure of the wind turbine (3) and the floating support structure (2) is located perpendicular to the center line (L) of the central coupling space (7).

10. A method for connecting a service vessel (1) and a floating support structure (2) for a wind turbine (3) using the system described in any one of claims 1 to 7, A: The step of positioning the ship contact means (6) at a lower, free position, B: The step of moving the stern coupling section (5) of the service vessel (1) into the central coupling space (7) of the floating support structure (2) to a position where the ship contact means (6) can interact with the support structure contact means (8), C: A step of raising the ship contact means (6) to a higher contact position for interaction with the support structure contact means (8), Methods that include...

11. The method according to claim 9, as referenced to claim 2 or 3, wherein step C includes the step of further lifting the ship contact means (6) upward so that a portion of the weight of the floating support structure (2) can be placed on the ship contact means (6).

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