Structure and installation method for installing a floating wind turbine

Abstract

An installation structure, comprising: a first floating structure that is an elongated first floating structure and has a first winch and a second winch spaced apart in the longitudinal direction; a second floating structure that is an elongated second floating structure and has a first winch and a second winch spaced apart in the longitudinal direction; a coupling structure that is attached to the first floating structure and the second floating structure and holds the first floating structure and the second floating structure so as to have an elongated open space therebetween; and a lower part of a wind turbine installed and arranged in the elongated open space between the first floating structure and the second floating structure, wherein the bottom of the lower part of the wind turbine is removably coupled to each of the first winch and the second winch of the first floating structure and the first winch and the second winch of the second floating structure by respective winch lines.

Description

Technical Field

[0001] The present invention relates to an installation structure for installing a floating wind turbine and a method for installing a floating wind turbine.

Background Art

[0002] Various configurations of floating wind turbines utilize various types of floating systems, including semi-submersible, barge, and spar types. The spar type is known for its strong resistance to wave action and can support a heavy upper structure. However, the water depth required to install a floating wind turbine using a spar-type floating system typically requires the spar-type floating system (lower part) and the upper part of the wind turbine to be transported separately from a pier to a position with sufficient water depth where the wind turbine and the final assembly of the lower part can be upended.

[0003] According to one approach described in US Patent Application Publication No. 2017 / 0197690 (Patent Document 1), the upper and lower parts are loaded onto a specially designed transport ship from a pier and transported to a position with sufficient water depth. At that position, the lower part is lifted by a crane and moved into the water, initially floating horizontally in the water. The upper end of the lower part is attached to the crane via a crane line, and then the lower part is brought into a vertical state by loading ballast into the lower part. Thereafter, the upper part is moved to a set of arm-shaped structures directly above the lower part. The lower part is lifted and moved by a crane and / or the ship is lowered so that the lower and upper parts are aligned with each other and joined by welding or bolting, etc.

[0004] In particular, the last step of integrating and joining the lower and upper parts described in Patent Document 1 is likely to be affected by the relative movement between the lower part fixed to the ship and the upper part. The vertical movement of the hull and / or the inclination of the lower part due to the sea current seems to make it very difficult to safely join the lower and upper parts.

[0005] Therefore, it is desirable to provide an improved installation of a floating wind turbine, and in particular, an installation that is less affected by local environmental conditions in deep waters, such as weather and ocean currents.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] In view of the above and other disadvantages of the prior art, an object of the present invention is to provide an improved installation of a floating wind turbine, and in particular, an installation that is less affected by local environmental conditions in deep waters, such as wind, waves, and ocean currents.

[0008] According to a first aspect of the present invention, there is provided an installation structure for installing a floating wind turbine, the wind turbine comprising an elongated lower part having a bottom and a top, and an upper part having at least one blade, the upper part being coupled to the top of the lower part when the floating wind turbine is installed, the installation structure comprising: a first elongated floating structure having a first winch and a second winch spaced apart in the longitudinal direction of the first floating structure; a second elongated floating structure having a first winch and a second winch spaced apart in the longitudinal direction of the second floating structure; a coupling structure attached to the first floating structure and the second floating structure and holding the first floating structure and the second floating structure so as to have an elongated open space therebetween; and a lower part of the wind turbine disposed in the elongated open space between the first floating structure and the second floating structure, the bottom of the lower part of the wind turbine being removably coupled to each of the first winch and the second winch of the first floating structure and the first winch and the second winch of the second floating structure by respective winch lines.

[0009] The present invention is based on the recognition that coupling the bottom of the lower part of a wind turbine to a winch line enables the lower part to be controlled and erected, and enables a stable connection between the lower part of the wind turbine and the first and second floating structures. Compared with the situation of Patent Document 1 that does not use a wire to couple the bottom of the lower part of the wind turbine to a ship that holds its upper part, the vertical sway of the ship can be considerably reduced, and the bending torque acting on the above structure that holds the top of the lower part of the wind turbine at a predetermined position so as to enable the connection between the lower part and the upper part of the wind turbine can be considerably reduced. As a result, the embodiment of the installation structure according to the present invention enables the installation of a wind turbine under weather and / or sea current conditions that cannot be carried out using currently available installation structures and installation techniques. Consequently, this brings about an increase in the operation rate of expensive equipment and ships, and the enhancement and improvement of installed offshore wind power plants.

[0010] According to a second aspect of the present invention, there is provided a method of installing a floating wind turbine, the method comprising the steps of: providing an installation vessel, the installation vessel comprising: a first elongated floating structure having a first winch and a second winch spaced apart in the longitudinal direction of the first floating structure; a second elongated floating structure having a first winch and a second winch spaced apart in the longitudinal direction of the second floating structure; and a coupling structure attached to the first floating structure and the second floating structure and configured to hold the first floating structure and the second floating structure with an elongated open space therebetween; substantially horizontally arranging an elongated lower part of the wind turbine within the open space between the first floating structure and the second floating structure of the installation vessel, wherein a bottom of the lower part of the wind turbine is removably coupled to the first winch and the second winch of the first floating structure and the first winch and the second winch of the second floating structure by respective winch lines; arranging an upper part of the wind turbine, which has at least one blade attached thereto, above the open space between the first floating structure and the second floating structure of the installation vessel and on the installation vessel; controlling each of the first winch and the second winch of the first floating structure and the first winch and the second winch of the second floating structure of the installation vessel such that the lower part of the wind turbine can be submerged until the lower part of the wind turbine is substantially vertically arranged within the open space between the first floating structure and the second floating structure of the installation vessel at the installation location; coupling the upper part of the wind turbine to the lower part of the wind turbine; and removing the winch lines from the bottom of the lower part of the wind turbine.

[0011] The steps of the method according to various embodiments of the present invention do not necessarily have to be performed in any particular order, so long as there are no technical requirements. For example, the upper part of the wind turbine may be arranged on the installation vessel before or after the lower part of the wind turbine is arranged within the elongated open space.

[0012] In summary, the present invention is an installation structure including: a first floating structure which is an elongated structure and has a first winch and a second winch spaced apart in the longitudinal direction; a second floating structure which is an elongated structure and has a first winch and a second winch spaced apart in the longitudinal direction; a coupling structure which is attached to the first floating structure and the second floating structure and holds the first floating structure and the second floating structure so as to have an elongated open space therebetween; and a lower part of a wind turbine installed in the elongated open space between the first floating structure and the second floating structure. The bottom of the lower part of the wind turbine is removably coupled to each of the first winch and the second winch of the first floating structure and the first winch and the second winch of the second floating structure by respective winch lines.

[0013] Hereinafter, these and other aspects of the present invention will be described in more detail with reference to the accompanying drawings showing exemplary embodiments of the present invention.

Brief Description of the Drawings

[0014]

Figure 1

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Embodiments for Carrying Out the Invention

[0015] Figure 1 schematically shows an offshore wind farm 1 including a plurality of wind turbines 3, where the plurality of wind turbines 3 are in the form of vertical axis wind turbines (VAWTs) floating in the ocean 5. These floating wind turbines 3 are examples of floating structures that can advantageously be installed using embodiments of the installation structure and installation method according to the present invention. However, it should be noted that the installation structure and installation method according to the present invention are not limited to the installation of VAWTs, but are also suitable for the installation of horizontal axis wind turbines (HAWTs) using a spar-type floating system.

[0016] Hereinafter, exemplary embodiments of the installation method according to the present invention, and the installation structure according to exemplary embodiments of the present invention, will be described with reference to the examples in FIGS. 2 to 11.

[0017] First, referring to FIG. 2, the elongated lower part 7 of the wind turbine 3 (of FIG. 1) is being lowered into the water from the quay 9 by the cranes 11a - b. The elongated lower part 7 can be manufactured near the quay 9, for example, by welding steel parts together.

[0018] When the lower part 7 of the wind turbine is floating approximately horizontally in the water, it is combined with the installation vessel 13 to form an installation structure according to an exemplary embodiment of the present invention. This will be described with reference to FIGS. 3 and 4a - b.

[0019] As schematically shown in FIG. 3, the installation vessel 13 includes an elongated first floating structure 15, an elongated second floating structure 17, and a connecting structure 19. The first floating structure 15 is in the form of a first version here and has a first winch 21 and a second winch 23 spaced apart in the longitudinal direction of the first floating structure 15. Similarly, the second floating structure 17 is in the form of a second version here and has a first winch 25 and a second winch 27 spaced apart in the longitudinal direction of the second floating structure 17. The connecting structure 19 is attached to the first floating structure 15 and the second floating structure 17 and holds the first floating structure 15 and the second floating structure 17 such that an elongated open space 29 exists between them, which is a catamaran configuration here.

[0020] The first winch 21 of the first floating structure 15 faces the first winch 25 of the second floating structure 17 with respect to the open space 29 between the first floating structure 15 and the second floating structure 17, and the second winch 23 of the first floating structure 15 faces the second winch 27 of the second floating structure 17 with respect to the open space 29 between the first floating structure 15 and the second floating structure 17.

[0021] In FIG. 3, the winches are shown arranged adjacent to all open spaces 29, which can simplify the routing of winch lines 35a - d. However, arranging at least one set of winches, for example, the second winch 23 of the first floating structure 15 and the second winch 27 of the second floating structure 17, further away from the open space 29 can be beneficial as it can provide a longer lever arm with respect to the torque caused by deep - sea currents etc. acting on the lower part 7 during and after standing. For example, the second winch 23 of the first floating structure 15 may be arranged on the long side of the first floating structure 15 opposite to the open space 29, and the second winch 27 of the second floating structure 17 may be arranged on the long side of the second floating structure 17 opposite to the open space 29. In some cases, by providing pulley assemblies on the first floating structure 15 and the second floating structure 17, it is ensured that the front winch lines 35b, 35d can run freely between the bottom 33 of the lower part 7 and the respective winches 23, 27.

[0022] Also in the longitudinal direction of the first floating structure 15 and the second floating structure 17, to provide a longer lever arm with respect to the torque caused by deep - sea currents etc. acting on the lower part 7 during and after standing, the first winches and the second winches of each floating structure can advantageously be longitudinally spaced apart from each other. Advantageously, the first winch 21 and the second winch 23 of the first floating structure 15 may be longitudinally spaced apart by a distance corresponding to at least 50% of the overall length of the first floating structure 15, and the first winch 25 and the second winch 27 of the second floating structure 17 may be longitudinally spaced apart by a distance corresponding to at least 50% of the overall length of the second floating structure 17. For further improvement of stability, the winches can be arranged to be even more widely spaced longitudinally, for example, spaced apart by at least 80% of the overall length of each floating structure.

[0023] As shown by the block arrows in FIG. 3, the installation vessel 13 can be moved relative to the floating lower part 7 of the wind turbine 3 and the lower part 7 can be disposed substantially horizontally within the open space 29 between the first floating structure 15 and the second floating structure 17 of the installation vessel 13.

[0024] Figures 4a and 4b are, respectively, a schematic plan view and a bottom view of an exemplary installation structure 31 according to the present invention. As shown in Figures 4a and 4b, the installation structure 31 arranges the lower part 7 of the wind turbine 3 in the open space 29 (Figure 3) between the first floating structure 15 and the second floating structure 17, and the bottom 33 of the lower part 7 is removably coupled to the first winch 21 and the second winch 23 of the first floating structure 15 and to the first winch 25 and the second winch 27 of the second floating structure 17 by respective winch lines 35a - d of these winches. In the example of Figures 4a - b, the installation structure 31 includes a winch - line - coupling structure 37 that is coupled to the respective winch lines 35a - d of the first winch 21 and the second winch 23 of the first floating structure 15 and the first winch 25 and the second winch 27 of the second floating structure 17. This winch - line - coupling structure 37 is here exemplified as a "bucket" removably coupled to the bottom 33 of the lower part 7 of the wind turbine 3. For example, since there is play between this "bucket" and the bottom 33 of the lower part 7, it may be possible to remove the "bucket" from the bottom 33 by further lowering the "bucket" when the lower part 7 is erected and floating. It should be understood that the winch - line - coupling structure 37 can be realized in many different ways. For example, a "plug" may extend axially so as to have play within a corresponding axial cavity at the bottom 33 of the lower part 7, or instead of the "bucket" shown in Figures 4a - b, a rigid or flexible net or grid may be used to surround the bottom 33 of the lower part 7, including the bottom end of the lower part 7. As an alternative to using the winch - line - coupling structure 37, the winch lines 35a - d may be directly and removably attached to the bottom 33 of the lower part 7, and in the desired case, remote control may be used to remove the winch lines 35a - d from the bottom 33 of the lower part 7. Such remote control can be achieved, for example, using one or more remotely operated vessels (ROV), which are well known to those skilled in the art.

[0025] When the installation structure 31 is formed as described above, solid ballast 39 can be added to the bottom 33 of the lower part 7. In FIG. 5, it is schematically shown that a suitable solid ballast 39, for example iron ore, is being moved from the jetty 9 through the opening 41 into the interior of the lower part 7, and the opening 41 is then closed. Also, as shown in FIG. 5, the top 43 of the wind turbine 3 can be lifted and moved from the jetty 9 to the installation vessel 13. The top 43 can advantageously be arranged on the coupling structure 19 of the installation vessel 13 above the open space 29 as shown with the lower part 7 currently being arranged. Alternatively, the top 43 may be arranged at other positions on the installation vessel 13, or two or more tops 43 may be arranged on the installation vessel 13. Although not shown in the figures, the installation vessel 13 may be equipped with a crane for moving the top 43 to the coupling structure 19.

[0026] When solid ballast 39 is added and the top 43 of the wind turbine 3 is arranged on the installation vessel 13, the installation structure 31 can be towed to a predetermined installation position as shown in FIG. 6. This predetermined installation position may be the final position of the wind power plant 1 in FIG. 1 or may be an intermediate position with sufficient water depth to enable erection.

[0027] As an alternative to the procedure described above with reference to FIGS. 2 to 6, one or more lower parts 7 may be towed or transported to the installation position, or the procedure described above with reference to FIGS. 3 to 6 may be carried out at the installation position instead of at the jetty 9.

[0028] During the path to the installation location, or when the installation structure 31 arrives at the installation location (or when the installation structure 31 is formed at the installation location), the procedure of raising the lower part 7 can be started. Due to the solid ballast (39, shown in Fig. 5) added to the bottom 33 of the lower part 7, the lower part 7 tries to rise. An intermediate state of the raising procedure is shown in Fig. 7. In this intermediate state, the first winch 21 and the second winch 23 of the first floating structure 15 of the installation structure 31 and the first winch 25 and the second winch 27 of the second floating structure 17 are controlled by a winch control system 45 coupled to each winch. In order to stabilize the installation structure by the keel formed by the lower part 7, the installation structure 31 may be controlled to this intermediate state before arriving at the installation location. In Fig. 7, the winch control system 45 is schematically represented by a simple box, and the connection to each winch is schematically represented by a line indicating a functional connection. It should be understood that the above control system may be distributed, and the connection may be wired or wireless. The winch control system 45 is configured to acquire signals indicating the tension of the winch lines 35a - d and individually control the operation of the winches based on the acquired signals. In particular, the winch control system 45 may be configured to control the first winch 21 and the second winch 23 of the first floating structure 15 and the first winch 25 and the second winch 27 of the second floating structure 17 so that the tension is maintained in all of the winch lines 45a - d during the raising procedure. This is to provide a continuous and stable connection between the lower part 7 of the wind turbine 3 and the installation vessel 13. As a result, the lower part 7 and the installation vessel 13 move together as one unit in response to external factors including wind, waves, and ocean currents.

[0029] The purpose of the procedure for raising the lower part 7 is to position the lower part 7 in alignment with the upper part 43 (which is arranged on and temporarily coupled to the coupling structure 19 of the installation vessel 13) and to couple the top 47 of the lower part 7 to the upper part 43 of the wind turbine 3, while maintaining the above-mentioned mechanical coupling between the lower part 7 and the installation vessel 13. For that purpose, the lower part 7 comprises at least one ballast tank (not shown), and the installation structure 31 may comprise a pump (not shown) for injecting or discharging sea water into or from its at least one ballast tank, to control the level of the lower part 7. Advantageously, the control of the winch by an adjustable sea water ballasting and winch control system 45 (Figure 7) may be used to lower the lower part 7 until the lower part 7 is in alignment with the upper part 43 (arranged on the coupling structure 19) directly below the upper part 43 and to maintain the tension of the wires 35a - d at a non-zero value. From that configuration, the lower part 7 can be lifted, possibly in combination with reducing the controllable ballast by controlling the winch, until the lower part 7 of the wind turbine 3 comes into contact with the upper part 43 of the wind turbine 3. Thereafter, the upper part 43 can be coupled to the lower part 7 of the wind turbine 3, for example by bolting corresponding flanges together. In particular, the configuration of the installation structure 31 according to an embodiment of the invention enables this coupling to be carried out under more difficult environmental conditions than previously possible. This is due to the stable mechanical coupling via the wires 35a - d between the installation vessel 13 and the lower part 7 of the wind turbine 3.

[0030] After this connection, the winch lines 35a - d are removed from the bottom 33 of the lower part 7. An example of such removal of the winch lines 35a - d is schematically shown in FIG. 9. This removal is achieved by controlling the winch (optionally in combination with a ballast pump) so that the "bucket" (or other structure) can be freed below the bottom 33 of the lower part 7 of the wind turbine 3 being currently assembled. Alternatively, as further described above, the winch lines 35a - d may be removed using an ROV or other means for remote control.

[0031] When the winch lines 35a - d are removed, the wind turbine 3 can be decoupled from the installation vessel 13. As schematically shown in FIG. 10, this decoupling can be achieved by first operating the winch to move the winch lines 35a - d (and any winch line coupling components 37) out of the way and then removing the wind turbine 3 from the coupling structure 19. In FIG. 10, it is schematically shown that the coupling structure 19 comprises a hinge portion 49 which can be pivoted out of the way to provide an open path along the open space 29 between the first floating structure 15 and the second floating structure 17. Alternatively, the coupling structure 19 may be analogously (although on a completely different scale) to the so - called "fifth wheel" of a trailer coupling and may be permanently open in one longitudinal direction in some cases. Finally, the installation vessel 13 is moved away from the assembled wind turbine 3 and can be used for the installation of the next wind turbine. The assembled wind turbine 3 may, in some cases, be towed to its final destination and then moored using mooring techniques known per se.

[0032] Those skilled in the art will understand that the present invention is in no way limited to the above - described preferred embodiments. On the contrary, many modifications and variations are possible within the scope of the appended claims.

[0033] In a claim, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claim. The mere fact that certain means are recited in mutually different dependent claims does not imply that a combination of these means cannot be used advantageously. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. An installation structure for the installation of a floating wind turbine, wherein the wind turbine comprises an elongated lower part having a bottom and a top, and an upper part having at least one blade, the upper part being coupled to the top of the lower part when the floating wind turbine is installed, and the installation structure is A first floating structure having an elongated shape, the first floating structure having a first winch and a second winch spaced apart in the longitudinal direction of the first floating structure, A second floating structure having an elongated shape, the second floating structure having a first winch and a second winch separated in the longitudinal direction of the second floating structure, A coupling structure attached to the first floating structure and the second floating structure, which holds the first floating structure and the second floating structure such that there is an elongated open space between them, It includes the lower part of the wind turbine, which is installed and positioned in the elongated open space between the first floating structure and the second floating structure, The bottom portion of the lower part of the wind turbine is an installation component that is detachably connected to the first and second winches of the first floating structure and the first and second winches of the second floating structure by their respective winch wires.

2. The mounting structure according to claim 1, wherein the coupling structure is configured as a catamaran and holds the first floating structure and the second floating structure.

3. The installation component according to claim 1 or 2, wherein the first winch and the second winch of the first floating structure are, with respect to the elongated open space, opposite to the first winch and the second winch of the second floating structure, respectively.

4. The first winch and the second winch of the first floating structure are separated in the longitudinal direction of the first floating structure by a distance corresponding to at least 50% of the total length of the first floating structure, and The installation component according to any one of claims 1 to 2, wherein the first winch and the second winch of the second floating structure are separated in the longitudinal direction of the second floating structure by a distance corresponding to at least 50% of the total length of the second floating structure.

5. The installation structure further comprises a winch control system coupled to the first winch and the second winch of the first floating structure, and to the first winch and the second winch of the second floating structure, and The winch control system is A signal indicating the tension of the winch wires of the first and second winches of the first floating structure and the first and second winches of the second floating structure is obtained, and, An installation component according to any one of claims 1 to 2, configured to individually control the operation of the first winch and the second winch of the first floating structure and the first winch and the second winch of the second floating structure based on the acquired signal.

6. The installation structure includes a winch wire coupling structure coupled to the winch wires of the first and second winches of the first floating structure, and the first and second winches of the second floating structure, and The installation component according to any one of claims 1 to 2, wherein the winch wire coupling component is detachably coupled to the bottom of the lower part of the wind turbine.

7. The installation structure according to claim 6, wherein the winch wire coupling structure surrounds the bottom of the lower part of the wind turbine, including the bottom end of the lower part of the wind turbine.

8. The floating wind turbine is a floating vertical-axis wind turbine (VAWT), according to the installation component according to any one of claims 1 to 2.

9. A method for installing a floating wind turbine, the said method is A step of providing an installation vessel, wherein the installation vessel is A first floating structure having an elongated shape, the first floating structure having a first winch and a second winch spaced apart in the longitudinal direction of the first floating structure, A second floating structure having an elongated shape, the second floating structure having a first winch and a second winch separated in the longitudinal direction of the second floating structure, A step to provide a ship for installation, comprising: a coupling structure attached to the first floating structure and the second floating structure, and holding the first floating structure and the second floating structure such that there is an elongated open space between them; A step of positioning the elongated lower portion of the wind turbine substantially horizontally within the open space between the first floating structure and the second floating structure of the installation vessel, wherein the bottom of the lower portion of the wind turbine is detachably connected to the first and second winches of the first floating structure and the first and second winches of the second floating structure by their respective winch wires, The step of positioning the upper part of the wind turbine, which has at least one blade attached thereto, on the installation vessel above the open space between the first floating structure and the second floating structure of the installation vessel, A step of controlling the first and second winches of the first floating structure and the first and second winches of the second floating structure of the installation vessel, so that the lower part of the wind turbine can be submerged until the lower part of the wind turbine is substantially positioned vertically within the open space between the first and second floating structures of the installation vessel at the installation location. The steps of connecting the upper part of the wind turbine to the lower part of the wind turbine, A method comprising the step of removing the winch wire from the bottom of the lower part of the wind turbine.

10. The step of controlling the first winch and the second winch of the first floating structure, and the first winch and the second winch of the second floating structure, Steps include obtaining a signal indicating the tension of the winch wires of the first and second winches of the first floating structure and the first and second winches of the second floating structure, The method according to claim 9, comprising the step of individually controlling the operation of the first winch and the second winch of the first floating structure and the first winch and the second winch of the second floating structure based on the acquired signal.

11. The method according to claim 9 or 10, wherein the first and second winches of the first floating structure and the first and second winches of the second floating structure are controlled to maintain the tension of the winch wire.

12. The method according to any one of claims 9 to 10, wherein the lower part of the wind turbine is raised until it contacts the upper part of the wind turbine, after the lower part of the wind turbine is positioned substantially vertically within the open space between the first floating structure and the second floating structure of the installation vessel.

13. The method according to claim 12, wherein the lower part of the wind turbine is lifted by controlling the first winch and the second winch of the first floating structure and the first winch and the second winch of the second floating structure to wind up the winch wire.

14. The method according to claim 13, wherein the lower part of the wind turbine is further raised by controlling the amount of ballast in the lower part of the wind turbine.

15. The winch wire coupling component is detachably coupled to the bottom of the lower part of the wind turbine. Each of the winch wires is connected to the winch wire coupling component, and The method according to any one of claims 9 to 10, wherein the winch wire is removed from the bottom of the lower part of the wind turbine by removing the winch wire coupling component from the bottom of the lower part of the wind turbine.

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