INSTALLING EQUIPMENT IN OFFSHORE MONOPILE FOUNDATIONS

Abstract

An equipment canister for supporting and enclosing electrical equipment of a wind turbine. The canister comprises: a housing defining or containing at least one internal platform for supporting the equipment; a lifting interface on a top of the housing; an at least one support formation positioned on or projecting laterally beyond a side wall of the housing. The support formation is capable of supporting the weight of the canister suspended therefrom when the canister is installed within a monopile wind turbine foundation. Various wind turbine arrangements and wind turbine assembly methods incorporating such a canister are also described.

Claims

1. A wind turbine equipment canister for supporting and enclosing electrical equipment of a wind turbine, the canister comprising: a housing defining or containing at least one internal platform for supporting the equipment; a lifting interface on a top of the housing; and at least one support formation positioned on or projecting laterally beyond a side wall of the housing, the side wall having at least a portion that tapers in diameter downwardly toward a base of the housing, and the support formation being capable of supporting the weight of the canister suspended therefrom when the canister is installed within a monopile foundation for a wind turbine.

2. The canister of claim 1, wherein the side wall comprises a cylindrical upper portion and a frusto-conical lower portion that tapers downwardly from the upper portion.

3. The canister of claim 1 or claim 2, wherein the downwardly-tapering portion of the side wall serves as the support formation.

4. The canister of any preceding claim, further comprising at least one vertically-oriented alignment formation on the side wall.

5. The canister of any preceding claim, wherein the top of the housing is substantially closed, or is penetrated by at least one opening that is closable by a hatch.

6. The canister of any preceding claim, wherein the support formation is substantially level with the top of the housing.

7. The canister of claim 6, wherein the support formation is a lateral extension of the top of the housing.

8. The canister of any of claims 1 to 5, wherein the support formation is at a level beneath the top of the housing.

9. The canister of any preceding claim, wherein the lifting interface comprises posts upstanding from the top of the housing, the posts having a quick-release mechanism for engagement with a lifting frame.

10. The canister of any preceding claim, attached to a work platform that extends laterally beyond a diameter of the housing.

11. The canister of claim 10, hanging beneath or extending through the work platform.

12. A monopile foundation for a wind turbine, comprising the canister of any preceding claim, wherein at least a part of the canister is contained within the monopile foundation.

13. The foundation of claim 12, wherein the housing is a sliding fit for longitudinal movement within an open top of the foundation.

14. The foundation of claim 12 or claim 13, further comprising an internal support formation that is positioned to engage the support formation of the canister.

15. The foundation of claim 14, wherein the internal support formation projects inwardly from a surrounding wall of the foundation.

16. The foundation of claim 14 or claim 15, wherein the internal support formation defines a support surface that is inclined inwardly and downwardly.

17. The foundation of any of claims 12 to 16, wherein the canister comprises at least one alignment formation as recited in claim 4 and the foundation comprises at least one internal guide formation that is configured for engagement with the alignment formation.

18. The foundation of claim 17, wherein the guide formation comprises downwardly-converging rails.

19. The foundation of any of claims 12 to 18, wherein the canister is recessed fully beneath a top end of the foundation.

20. The foundation of any of claims 12 to 18, wherein the support formation of the canister rests upon a top interface of the foundation that is configured for mounting a tower upon the foundation.

21. The foundation of claim 20, wherein the support formation of the canister is disposed inboard of an outer portion of the top interface, which outer portion is configured for mounting the tower upon the foundation.

22. The foundation of any of claims 12 to 21, wherein the support formation of the canister overlies an upper hang-off formation of a support structure that embraces the canister.

23. The foundation of claim 22, wherein a lower part of the support structure comprises an inwardly-facing support formation that complements the housing of the canister.

24. A wind turbine comprising a tower mounted on the foundation of any of claims 12 to 23, enclosing the canister.

25. The wind turbine of claim 24, wherein the support formation of the canister is sandwiched between mutually-opposed ends of the foundation and the tower.

26. The wind turbine of claim 25, wherein fastenings that join the tower to the foundation extend through holes in the support formation of the canister.

27. The wind turbine of any of claims 24 to 26, further comprising an external work platform.

28. The wind turbine of claim 27, wherein the tower and the foundation are in mutual abutment.

29. The wind turbine of claim 28, wherein the tower and/or the foundation extend through a wider opening that penetrates the work platform.

30. The wind turbine of claim 28, wherein the work platform is sandwiched between mutually-opposed ends of the foundation and the tower.

31. The wind turbine of claim 30, wherein the work platform is penetrated by an opening that is narrower than the mutually-opposed ends of the foundation and the tower.

32. The wind turbine of claim 30 or claim 31, wherein fastenings that join the tower to the foundation extend through holes in the work platform.

33. The wind turbine of any of claims 27 to 32, wherein the work platform is supported by legs that are disposed externally around the foundation.

34. The wind turbine of any of claims 24 to 33, wherein the support formation of the canister rests on a bottom interface of the tower, which interface is configured to mount the tower to the foundation.

35. A wind turbine comprising: a monopile foundation; a tower mounted atop the foundation; and a canister disposed at least partially within the foundation and supporting and enclosing electrical equipment of the wind turbine, wherein a side wall of a housing of the canister has at least a portion that tapers in diameter downwardly toward a base of the housing; and/or an external work platform extending outside the foundation or the tower; wherein a part of the canister and/or the work platform is sandwiched between mutually-opposed ends of the foundation and the tower.

36. The wind turbine of claim 35, wherein fastenings that join the tower to the foundation extend through holes in the sandwiched part of the canister and/or the work platform.

37. A method of assembling a wind turbine on a pre-installed monopile foundation, the method comprising: lowering a canister into an open top of the foundation, the canister supporting and enclosing electrical equipment of the wind turbine; and mounting a tower on the foundation, sandwiching part of the canister between mutually-opposed ends of the foundation and the tower.

38. A method of assembling a wind turbine on a pre-installed monopile foundation, the method comprising: lowering an external work platform onto an open top of the foundation; and mounting a tower on the foundation, sandwiching part of the work platform between mutually-opposed ends of the foundation and the tower.

39. The method of claim 38, comprising: lowering a canister into an open top of the foundation, the canister supporting and enclosing electrical equipment of the wind turbine; supporting the external work platform on the canister; and enclosing the canister when mounting the tower on the foundation.

40. The method of claim 39, comprising lowering the work platform and the canister onto the foundation when the work platform and the canister are conjoined.

41. A method of assembling a wind turbine on a pre-installed monopile foundation, the method comprising: lowering a canister into an open top of the foundation, the canister supporting and enclosing electrical equipment of the wind turbine; and suspending at least part of the canister from a support formation of the foundation.

42. The method of claim 41, further comprising mounting a tower on the foundation in mutual end-to-end abutment, enclosing the canister.

43. The method of claim 41 or claim 42, comprising sliding the canister down within the foundation.

44. The method of any of claims 41 to 43, comprising orienting the canister about horizontal and/or vertical axes in consequence of downward movement of the canister relative to the foundation.

45. The method of any of claims 41 to 44, comprising seating the canister into a support structure that is suspended from the support formation.

46. The method of any of claims 41 to 44, comprising: suspending the canister from an inboard side of the support formation; and mounting a tower on an outboard side of the support formation.

47. A method of assembling a wind turbine on a pre-installed monopile foundation, the method comprising: mounting at least a lower part of a tower on the foundation; and lowering a canister into the foundation through the tower, or the part of the tower, that is mounted on the foundation, the canister supporting and enclosing electrical equipment of the wind turbine.

48. The method of claim 47, comprising suspending at least part of the canister from a support formation of the tower.

49. The method of claim 48, wherein the support formation of the tower is also a bottom interface formation for mounting the tower on the foundation.

Description

[0063] In order that the invention may be more readily understood, reference will now be made, by way of example, to the accompanying drawings in which:

[0064] FIG. 1 is a side view of a canister of the invention;

[0065] FIG. 2 is a further side view of the canister of FIG. 1;

[0066] FIG. 3 is a perspective view of the canister of FIGS. 1 and 2, partially cut away to show its internal features;

[0067] FIG. 4 is a top plan view of the canister of FIGS. 1 to 3;

[0068] FIG. 5 is an exploded perspective view showing the canister of FIGS. 1 to 4 in conjunction with the top of a monopile foundation, a work platform and a lifting frame that is cooperable with a lifting interface on top of the canister;

[0069] FIG. 6 is a side view of the monopile foundation shown in FIG. 5 supporting the work platform also shown in FIG. 5 and containing the canister of FIGS. 1 to 4;

[0070] FIGS. 7a to 7c are a sequence of schematic sectional side views showing a first embodiment and method of the invention for assembling a canister with a monopile foundation and a work platform;

[0071] FIGS. 8a to 8c are a sequence of schematic sectional side views showing a second embodiment and method of the invention for assembling a canister with a monopile foundation and a work platform;

[0072] FIGS. 9a and 9b are schematic sectional side views showing a third embodiment and method of the invention for assembling a canister with a monopile foundation and a work platform;

[0073] FIGS. 10a to 10c are a sequence of schematic sectional side views showing a fourth embodiment and method of the invention for assembling a canister with a monopile foundation and a work platform;

[0074] FIGS. 11a to 11c are a sequence of schematic sectional side views showing a fifth embodiment and method of the invention for assembling a canister with a monopile foundation and a work platform; and

[0075] FIGS. 12a to 12c are a sequence of schematic sectional side views showing a sixth embodiment and method of the invention for assembling a canister with a monopile foundation and a work platform.

[0076] Referring firstly to FIGS. 1 to 4 of the drawings, a wind turbine equipment canister 10 of the invention comprises a hollow, substantially closed housing or shell whose side wall is rotationally symmetrical about a vertical central longitudinal axis 12. The side wall of the shell comprises a cylindrical upper portion 14 of substantially constant circular cross-section and a frusto-conical lower portion 16 that tapers downwardly from the diameter of the upper portion 14.

[0077] The shell is completed and closed at its bottom end by a flat circular base 18 and at its top end by a generally flat circular roof 20. The base 18 and the roof 20 lie in respective horizontal planes. The roof 20 is surmounted by a lifting interface that, in this example, comprises hollow vertical posts 22 equiangularly spaced about the central longitudinal axis 12. The canister 10 is stable when free-standing on its base 18.

[0078] A male hang-off formation projects outwardly in a horizontal direction from the upper portion of the side wall. In this example, the hang-off formation takes the form of a circumferential flange 24 surrounding the shell in alignment with the upper portion 14. The flange 24 is shown here at the level of the roof 20, for example as a horizontal extension of the roof 20.

[0079] The flange 24 need not be continuous as shown here but could be interrupted by one or more circumferential gaps. In other examples, a flange or other hang-off formation could be at a different vertical level along the canister 10, for example at the level of the lower portion 16 or at the interface between the upper and lower portions 14, 16. It would also be possible to support the canister 10 other than by a hang-off arrangement.

[0080] Elongate alignment formations 26 mounted externally on the side wall of the shell lie in respective vertical planes that also contain the central longitudinal axis 12. Those planes, and hence the alignment formations 26, are also equiangularly spaced about the central longitudinal axis 12.

[0081] On its upper side within the shell, the base 18 defines a lower equipment platform or deck of the canister 10. A parallel upper equipment platform or deck 28 extends across the canister 10 at the junction between the upper and lower portions 14, 16 of the shell. The base 18 and the upper equipment deck 28 support items of equipment (not shown) that are required for operation of the wind turbine, such as switchgear, a transformer, a converter and/or control equipment. When the canister 10 is installed in a wind turbine, cables from outside the canister 10 can be connected to that equipment to convey power and data signals within, into and out of the wind turbine as required. The roof 20 may, of course, also serve as an equipment deck after the canister 10 has been installed.

[0082] The roof 20 is penetrated by a central opening 30 that communicates with the interior of the shell. The opening 30 can be closed by a hatch 31 shown here beside the opening, hence weatherproofing the roof 20 and substantially sealing the shell of the canister 10. When the hatch is open as shown, a frame 32 within the shell may extend upwardly from the base 18 and through the upper equipment deck 28 to protrude above the roof 20 through the central opening 30. The frame 32 may, for example, support cables that extend into the tower of the completed wind turbine structure and/or may serve as the base of a lift shaft also extending into the tower. At its lower end, the frame 32 may extend to cable hang-off provisions mounted on the base 18 for supporting cables that, in use, hang down toward the seabed into the foundation beneath the canister 10.

[0083] An internal ladder 34 provides alternative access between the base 18, the upper equipment deck 28 and the roof 20 of the canister 10. Again, a hatch 35 may close the opening that accommodates the ladder 34.

[0084] Moving on now to FIGS. 5, 6 and 7a to 7c, these drawings shows the canister 10 in its context of use, in which the canister 10 is supported above sea level in the monopile foundation of a wind turbine.

[0085] In the exploded view of FIG. 5, the canister 10 is shown in coaxial alignment with the open top of a pre-installed foundation in the form of a tubular monopile 36 that receives the canister 10 telescopically as the canister 10 is lowered by a crane. In effect, the canister 10 is installed as a cartridge into a socket within the open top of the monopile 36. FIG. 7a also shows the canister 10 when lowered into position within the monopile 36.

[0086] For the purpose of lifting and lowering the canister 10, FIGS. 5 and 7a show a lifting frame 38 that can be engaged from above with the lifting interface of the canister 10. Specifically, the lifting frame 38 comprises vertical pins 40 that are positioned to engage within respective ones of the upstanding tubular posts 22 on the roof 20 of the canister 10. A mechanical quick-connector system such as the aforementioned Balltech LiftLOK may act between the pins 40 and the posts 22 to engage and disengage the lifting frame 38. FIG. 7a also shows a load orientation system 42 that may be interposed between the lifting frame 38 and the hook 44 of a crane to control the orientation of the canister 10 about a vertical axis.

[0087] The monopile 36 has a female hang-off formation that forms part of a first interface of the monopile 36, namely that between the monopile 36 and the canister 10. The female hang-off formation is exemplified here by an inner circumferential flange 46 that is cooperable with the corresponding flange 24 of the canister 10 to support the weight of the canister 10. The inner flange 46 lies in a horizontal plane that is spaced sufficiently beneath the top of the monopile 36 as to recess the top of the canister 10 at a level beneath the horizontal plane of the upper end of the monopile 36.

[0088] Conveniently, cooperation between the flange 24 of the canister 10 and the flange 46 of the monopile 36 effects or enables a seal. That seal protects the interior of the monopile 36 and the portion of the canister 10 beneath the flange 46 from the weather once the canister 10 has been installed. The roof 20 of the canister 10 may also be weatherproofed, for example with hatches 31, 35 as noted above. This means that a temporary cap over the open top of the monopile 36 is not essential to protect the equipment within the canister 10 from the weather, hence simplifying the wind turbine installation process.

[0089] FIG. 5 shows downwardly-converging Y-shaped alignment rails 48 that are angularly spaced around the interior of the monopile 36. Each of the alignment rails 48 serves as a guide formation, being positioned to receive a respective one of the alignment formations 26 of the canister 10 and to guide the canister 10 into correct angular alignment with the monopile 36 as the canister 10 is lowered into the open top of the monopile 36. Once seated into the monopile 36 in the correct angular alignment, the canister 10 may be held down by anti-lift fixings acting between the cooperating circumferential flanges 24, 46 of the canister 10 and the monopile 36.

[0090] Externally, the monopile 36 is encircled by an angularly-spaced array of outwardly-projecting studs 50 that lie in a horizontal plane spaced beneath the top of the monopile 36. The studs 50 align with, and support, respective legs 52 of a work platform 54 that is also shown in FIGS. 5, 6, 7b and 7c. Thus, the studs 50 and the legs 52 together define a second interface of the monopile 36, namely that between the monopile 36 and the work platform 54. Specifically, the legs 52 hang from the work platform 54 and lie against the exterior of the monopile 36 to engage the studs 50. That engagement between the legs 52 and the studs 50 fixes the work platform 54 relative to the monopile 36 as shown in FIG. 7b before a tubular tower 56 is mounted on the monopile 36 as shown in FIGS. 6 and 7c.

[0091] FIG. 6 also shows a ladder arrangement 58 beneath and connecting to the work platform 54 that provides for docking a service vessel to the wind turbine and for access of personnel to the wind turbine via the work platform 54.

[0092] FIG. 5 shows that a circular opening 60 penetrates the work platform 54 in coaxial alignment with the top of the monopile 36. In this example, the work platform 54 is asymmetric in plan view, having a major portion laterally offset to one side of the opening 60.

[0093] In this example, the opening 60 in the work platform 54 has an inner diameter that is slightly smaller than the outer diameter of the top of the monopile 36. The opening 60 is surrounded by a circular array of holes 62 that together receive a corresponding array of pins or bolts 64 projecting vertically from a flange 66 at the top of the monopile 36 and into a complementary flange 68 at the bottom of the tower 56 as shown in FIG. 7c.

[0094] The bolts 64 and flanges 66, 68 form part of a third interface of the monopile 36, namely that between the monopile 36 and the tower 56 that surmounts the monopile 36. It will be apparent that the peripheral region of the work platform 54 immediately surrounding the opening 60 is sandwiched and indeed clamped between the monopile 36 and the tower 56, thereby further locating the work platform 54 relative to the monopile 36.

[0095] FIGS. 7a to 7c show further provisions for defining the first interface between the monopile 36 and the canister 10. These provisions may be additional to, or instead of, the cooperating flanges 24, 46 at or near the top of the canister 10. They comprise additional cooperating flanges 70 at a lower position on the upper portion 14 of the side wall, and wedge-faced supports 72 extending inwardly from the side wall of the monopile 36 in opposition to the lower portion 16 of the side wall. The wedge faces of the supports 72 engage, and complement the inclination and curvature of, the frusto-conical lower portion 16 of the side wall. The supports 72 could be discrete structures angularly-spaced around the central longitudinal axis 12 of the canister 10 or could be parts of a circumferentially-continuous ring that encircles the interior of the monopile 36.

[0096] The flanges 24, 46, the additional flanges 70 and the supports 72 may be used individually or in any combination. In the remaining drawings, the flanges 70 are omitted for simplicity but the supports 72 are retained or replaced with equivalent features.

[0097] FIGS. 8a to 12c show various other arrangements and methods of the invention for assembling a wind turbine that incorporates a canister 10 of the invention. Like numerals are used for like features.

[0098] The arrangement and method steps shown in FIGS. 8a to 8c correspond to those of FIGS. 7a to 7c except that the circular opening 60 in the work platform 54 is wider than the outer diameter of both the monopile 36 and the tower 56. Consequently, the monopile 36 and/or the tower 56 can extend through opening 60 and hence through the work platform 54 to abut directly at their mutual interface, where the bolts 64 extend through the abutting flanges 66, 68. In this arrangement, unlike that of FIGS. 7a to 7c, the work platform 54 is not clamped between monopile 36 and the tower 56 but instead relies upon engagement of the legs 52 under the work platform 54 with the studs 50 on the exterior of the monopile 36.

[0099] FIGS. 9a and 9b show a variant of the invention in which the work platform 54 is attached directly to the canister 10 before or after the canister 10 is installed in the monopile 36. In the former case, the work platform 54 and the canister 10 are installed together on the monopile 36, being lifted together as an assembly by a lifting frame 38 as shown in FIG. 9a. For example, the canister 10 could be pre-inserted into the opening 60 in the work platform.

[0100] In the example shown in FIGS. 9a and 9b, the work platform 54 is clamped between the monopile 36 and the tower 56 in a manner similar to that shown in FIG. 7c. In other words, the bolts 64 extend through the flanges 66, 68 and through the platform 54 sandwiched between the flanges 66, 68. In view of this, and as the work platform 54 can also rely upon its attachment to the canister 10 for support, legs 52 under the work platform 54 engaging with studs 50 on the monopile 36 are optional and have been omitted from these drawings. However, a second interface such as that defined by the studs 50 and the legs 52 could be provided, for example in an alternative arrangement in which the opening 60 of the work platform 54 is wide enough for the monopile 36 and the tower 56 to abut directly at their mutual interface in a manner akin to that shown in FIG. 8c.

[0101] FIGS. 10a to 10c show an arrangement of the invention in which the top of the canister 10 is not recessed below the top of the monopile 36 but instead projects above the top of the monopile 36. In this example, the flange 24 of the canister 10 lies on an inwardly-projecting flange 66 that is positioned at or near to the top of the monopile 36. The arrangement is such that at least part of the canister 10, in this case the posts 22 of the lifting interface, extends above the top of the monopile 36. Thus, this upwardly-projecting part of the canister 10 lies within the base of the tower 56 as shown in FIG. 10c.

[0102] In FIGS. 10b and 10c, the work platform 54 is supported, optionally, by legs 52 under the work platform 54 engaged with studs 50 on the monopile 36. Also, the opening 60 of the work platform 54 is wide enough for the monopile 36 and the tower 56 to abut directly at their mutual interface in a manner akin to that shown in FIG. 8c. However, with a narrower opening 60, it would instead be possible for the work platform 54 to be clamped between the monopile 36 and the tower 56 like the arrangement of FIGS. 7c and 9b. In either case, the flange 24 of the canister 10 could be clamped between the flanges 66, 68 of the monopile 36 and the tower 56, or between one of the flanges 66, 68 and the work platform 54. Also, the bolts 64 that extend through the flanges 66, 68 of the monopile 36 and the tower 56 could, in principle, also extend through the flange 24 of the canister 10.

[0103] The arrangement of the invention shown in FIGS. 11a to 11c corresponds to that shown in FIGS. 10a to 10c except that an intermediate support structure 74 hangs from the inwardly-projecting flange 46 of the monopile 36. The support structure 74 has a hang-off flange 76 at its upper end that lies on the flange 66 of the monopile 36. The flange 24 of the canister 10 lies on the hang-off flange 76 of the support structure 74 and so is also supported by the underlying flange 66 of the monopile 36.

[0104] The support structure 74 also an inwardly-facing frusto-conical surface 78 at its lower end that complements, receives and supports the lower portion 16 of the side wall of the canister 10. That frusto-conical surface 78 replaces the supports 72 of the preceding embodiments, which are therefore omitted from FIGS. 11a to 11c.

[0105] The variants mentioned in relation to the arrangement of FIGS. 10a to 10c could also be applied to the arrangement of FIGS. 11a to 11c. Analogously, the hang-off flange 76 of the support structure 74 could be clamped directly or indirectly between the flanges 66, 68 of the monopile 36 and the tower 56. Similarly, the bolts 64 that extend through those flanges 66, 68 of the monopile 36 and the tower 56 could extend through the hang-off flange 76. However, in the arrangement shown in FIG. 11c, the hang-off flange 76 is inboard of the inwardly-projecting flange 68 at the base of the tower 56. The complementary flange 66 at the top of the monopile 36 is extended in a radially inward direction to accommodate the combined width of the concentric flanges 62, 76.

[0106] Turning finally to FIGS. 12a to 12c, these drawings show a further arrangement of the invention in which the canister 10 is lowered into the monopile 36 only after mounting the tower 56 to the monopile 36 as shown in FIG. 12c. This arrangement is apt to be used where the tower 56 comprises stacked sections affixed end-to-end, meaning that the canister 10 does not have to be lifted to and lowered from the full height of the tower 56 but only to and from the height of its lowest section.

[0107] In the example shown in FIG. 12c, the flange 24 of the canister 10 rests upon an inwardly-projecting flange 68 within the tower 56, for example at the base of the tower 56 as shown. The major portion of the canister 10 beneath the flange 68 hangs into the open top of the monopile 36, where optional supports 72 cradle the lower portion 16 of the side wall of the canister 10.

[0108] Again, the work platform 54 shown in FIGS. 12b and 12c is supported, optionally, by legs 52 under the work platform 54 engaged with studs 50 on the monopile 36. Also, the opening 60 of the work platform 54 is wide enough for the monopile 36 and the tower 56 to abut directly at their mutual interface in a manner akin to that shown in FIGS. 8c, 10c and 11c. However, with a narrower opening 60, it would instead be possible for the work platform 54 to be clamped between the monopile 36 and the tower 56 like the arrangement of FIGS. 7c and 9b. In either case, the bolts 64 that extend through the flanges 66, 68 of the monopile 36 and the tower 56 could, in principle, also extend through the flange 24 of the canister 10.