METHOD FOR MANUFACTURING A WIND TURBINE, TOWER OF A WIND TURBINE AND WIND TURBINE

Abstract

Provided is a method for manufacturing a wind turbine, the wind turbine including a high voltage cable configured to connect a generator of the wind turbine with a switch gear of the wind turbine, the method: a) guiding the high voltage cable inside a tower of the wind turbine from an upper part of the tower to a lower part of the tower, and b) returning the high voltage cable at the lower part of the tower up again. Returning the high voltage cable at the lower part of the tower up again simplifies storing an additional length of the high voltage cable inside the tower.

Claims

1. A method for manufacturing a wind turbine, the wind turbine comprising a high voltage cable configured to connect a generator of the wind turbine with a switch gear of the wind turbine, the method comprising: a) guiding the high voltage cable inside a tower of the wind turbine from an upper part of the tower to a lower part of the tower; and b) returning the high voltage cable at the lower part of the tower up again.

2. The method according to claim 1, wherein the high voltage cable is returned at the lower part of the tower up again such that it forms a U-shape.

3. The method according to claim 1, wherein the high voltage cable is returned at least up to a first platform of the tower.

4. The method according to claim 3, wherein the high voltage cable is returned by a winch.

5. The method according to claim 1, comprising the step of transporting, the tower produced in accordance with steps a) and b) to a wind harvesting site.

6. The method according to claim 1, comprising: arranging the tower on a transition piece of the wind turbine, the transition piece being connected to a foundation of the wind turbine; and lowering the high voltage cable into the transition piece.

7. The method according to claim 2, wherein the high voltage cable is lowered into the transition piece by lowering the U-shape of the high voltage cable into the transition piece.

8. The method according to claim 6, wherein the high voltage cable is lowered into the transition piece by lowering it through cutouts in one or more platforms of the tower and/or the transition piece.

9. The method according to claim 8, wherein one or more of the cutouts include a roller assembly to guide the high voltage cable through the cutout.

10. The method according to claim 1, comprising the step of fixing the high voltage cable to a ladder of the wind turbine.

11. The method according to claim 1, comprising: hoisting a lower part of the high voltage cable into a tray of a support structure, the support structure being in particular located on a switch gear footbridge; and adjusting an inclination of the tray to a length of the high voltage cable.

12. The method according to claim 11, wherein the lower part of the high voltage cable is hoisted into the tray by a second winch and/or a carrying strap.

13. The method according to claim 11, comprising pivoting at least a portion of the support structure to change an orientation of the lower part of the high voltage cable.

14. A tower of a wind turbine, comprising: a high voltage cable configured to connect a generator of the wind turbine with a switch gear of the wind turbine, wherein the high voltage cable is arranged inside the tower such that it is guided from an upper part of the tower to a lower part of the tower, where it is returned up again.

15. A wind turbine, comprising: a generator, a switch gear, a platform above the switch gear, a high voltage cable connecting the generator to the switch gear; and means to lower a returned portion of the high voltage cable from the platform towards the switch gear.

16. The method according to claim 4, wherein winch located on the first platform or on a second platform of the tower and/or including a rope connected to a free end of the high voltage cable.

17. The method according to claim 5, wherein the step of transporting is by a vessel.

18. The method according to claim 6, further comprising the step of lowering includes lowering the high voltage cable towards the switch gear in the transition piece.

Description

BRIEF DESCRIPTION

[0062] Some of the embodiments will be described in detail, with references to the following Figures, wherein like designations denote like members, wherein:

[0063] FIG. 1 shows, in partial cross-section, a wind turbine according to an embodiment;

[0064] FIG. 2 shows, in cross-section, a portion of a tower of the wind turbine of FIG. 1;

[0065] FIG. 3 shows schematically the transport of the tower of FIG. 2 to a wind harvesting site according to an embodiment;

[0066] FIG. 4 shows, in cross-section, a portion of the tower of the wind turbine of FIG. 2 erected on a transition piece;

[0067] FIG. 5 shows, in plan view, a platform of the transition piece FIG. 4;

[0068] FIG. 6 shows, in partial perspective view, a portion of the transition piece of FIG. 4;

[0069] FIG. 7 shows, in perspective view, a switch gear footbridge with a support structure according to an embodiment; and

[0070] FIG. 8 shows a flowchart illustrating a method for manufacturing a wind turbine according to an embodiment.

DETAILED DESCRIPTION

[0071] FIG. 1 shows an offshore wind turbine 1 according to an embodiment.

[0072] The wind turbine 1 comprises a rotor 2 connected to a generator 3 arranged inside a nacelle 4. The nacelle 4 is arranged at the upper end of a tower 5 of the wind turbine 1. The tower 5 is arranged on a transition piece 6. The transition piece 6 is a “Super Extended Transition Piece” with a height of 40 meters or more. The transition piece 6 is erected on a monopile 7 which is driven into the sea bed 8.

[0073] The rotor 2 comprises, for example, three rotor blades 9. The rotor blades 9 are connected to a hub 10 of the wind turbine 1. A shaft (not shown) connects the hub 10 to the generator 3.

[0074] The generator 3 is electrically connected to a switch gear 11 in the transition piece 6 by a high voltage cable 12.

[0075] The tower 5 comprises one or more tower sections 13, 14, 15. In the example of FIG. 1, the tower 5 comprises a bottom tower section 13, a middle tower section 14, and a top tower section 15. The tower sections 13, 14, 15 include each one or more flanges 18 bolted to a corresponding flange 18 of another tower section 13, 14, 15. Further, the bottom tower section 13 of the tower 5 includes a flange 21 for a bolted connection with the transition piece 6.

[0076] The tower 5 comprises inside one or more platforms 22, 23, 24, 25. The tower 5 comprises, for example, a low voltage platform 22 in the bottom tower section 13 on which a low voltage transformer (not shown) is located. The tower 5 comprises, for example, bolt platforms 23 and 24 configured for a worker to bolt the corresponding tower sections 13, 14, 15 to each other when assembling the tower 5.

[0077] The transition piece 6 comprises on its outside a landing platform 26 to provide access to the interior of the transition piece 6 and the tower 5. The transition piece 6 comprises further one or more platforms 27, 28, 29 inside. The transition piece 6 comprises, in particular, a switch gear platform 27 on which the switch gear 11 is arranged. Further, the transition piece 6 comprises, for example, a switch gear footbridge 28. The transition piece 6 may further comprise a bolt platform 29 for a worker to connect the transition piece 6 and the tower 5 by bolts.

[0078] The transition piece 6 includes inside at a lower end thereof above the monopile 7 an airtight platform 30 to prevent poisonous gases from the sea bed 8 from entering the upper part of the transition piece 6.

[0079] In the following, a method for manufacturing the wind turbine 1 of FIG. 1 is described.

[0080] FIG. 2 shows a detailed view of a portion of the tower 5 of FIG. 1, in particular the bottom tower section 13.

[0081] In a step S1 of the method, the high voltage cable 12 is guided inside the tower 5 of the wind turbine 1 from an upper part of the tower 5 to a lower part of the tower 5. The upper part of the tower 5 is, for example, the platform 25 shown in FIG. 1. The lower part of the tower 5 is, for example, a part below the platform 22. The portion of the high voltage cable 12 guided from the upper part of the tower 5 (platform 25) to the lower part of the tower 5 (below platform 22) is henceforth called first portion 31 (FIG. 2) of the high voltage cable 12.

[0082] In a step S2, the high voltage cable 12 is returned at the lower part of the tower 5, i.e. below platform 22, up again. In the example of FIG. 2, the high voltage cable 12 is returned with its free end 48 up to the bolt platform 23 of the bottom tower section 13. The portion of the high voltage cable 12 returned from the lower part of the tower (below platform 22) up to the bolt platform 23 is henceforth called second portion 32 (FIG. 2) of the high voltage cable 12. The high voltage cable 12 forms a U-shape 33 between the first portion 31 and the second portion 32 (FIG. 2). The U-shape 33 comprises a semi-circular portion, a first leg being continuous with the first portion 31 and a second leg being continuous with the second portion 32.

[0083] The high voltage cable 12 is returned by a winch 34 arranged on the platform 23. The winch 34 includes a rope 35 (FIG. 4) which is connected to the free end 48 of the second portion 32 of the high voltage cable 12 via a protection cap 36. The protection cap 36 is, for example, a steel cap releasably fastened to the free end 48. By winding up the rope 35, the winch 34 pulls up the second portion 32 of the high voltage cable 12.

[0084] In a step S3, the tower 5 comprising the high voltage cable 12 guided from the platform 25 to below the platform 22 and returned up again to the platform 23 is transported by a jack-up vessel 19 to the wind harvesting site 20 out at sea.

[0085] FIG. 3 shows schematically the route of transport from a factory hall 16 to a harbor site 17 and further to the offshore wind harvesting site 20. The tower sections 13, 14, 15 that have been manufactured at the factory hall 16 are transported to the harbor site 17. At the harbor site 17, the tower sections 13, 14, 15 are assembled to form the tower 5 and the high voltage cable 12 is installed inside the tower 5 according to method steps Si and S2. From the harbor site 17 the tower 5 is transported by the vessel 19, in particular in a vertical orientation, to the wind harvesting site 20.

[0086] In a step S4, the tower 5 is arranged on the transition piece 6 (FIG. 3) which was connected beforehand to a foundation of the wind turbine 1 such as a monopile 7.

[0087] In a step S5, the high voltage cable 12 is lowered into the transition piece 6, as shown in FIG. 4. By unwinding the rope 35 of the winch 34, the high voltage cable 12 is gradually lowered into the transition piece 6 and towards the switch gear 11 on the switch gear platform 27. In particular, the U-shape 33 of the high voltage cable 12 is lowered successively into the transition piece 6. In order to pass platforms between the lower part of the tower 5 and the switch gear 11, such as the platform 29 of the transition piece 6, these platforms comprise cutouts 38. FIG. 5 shows exemplarily a cutout 38 of the platform 29 in a plan view. The U-shape 33 of the high voltage cable 12 is lowered through the cutout 38. The cutout 38 includes a roller assembly 39 to guide the high voltage cable 12 smoothly through the cutout 38. As shown in the enlarged view of FIG. 5, the roller assembly 39 includes one or more rolls 39 arranged in one of the corners of the cutout 38.

[0088] After the high voltage cable 12 has been lowered all the way to the switch gear platform 27, the rope 35 and the protection cap 36 are disconnected from the high voltage cable 12.

[0089] In a step S6, the high voltage cable 12 is fixed to a ladder 40 inside the transition piece 6 at several connection points 41 in order to support the weight of the high voltage cable 12, as shown in FIG. 6.

[0090] In a step S7, a lower part 49 of the high voltage cable 12 is hoisted into a tray 42 of a support structure 43 located on the switch gear footbridge 28, as shown in FIGS. 6 and 7. The lower part 49 of the high voltage cable 12 is hoisted by a second winch 44 arranged on the platform 29 and by a carrying strap 45 (FIG. 6). The carrying strap 45 includes a mesh structure that is laid around a portion of the lower part 49 of the high voltage cable 12. The second winch 44 then hoists the carrying strap 45 that is carrying the lower part 49 of the high voltage cable 12. Thereby, the second winch 44 hoists the high voltage cable 12 into the tray 42 (FIG. 7).

[0091] In a step S8, the inclination of the tray 42 is adjusted to a length of the high voltage cable 12. By increasing the inclination of the tray 42 for shorter cables 12 and decreasing the inclination for longer cables 12, it is possible to take up tolerances of the high voltage cable 12. As shown in FIG. 7, the support structure 43 includes means 46 to adjust the inclination of the tray 42. The means 46 include, for example, two supporting plates with each three bolts. FIG. 7 shows three different examples for inclining the tray 42 denoted with 42, 42′ and 42″. In the first example, the tray 42 is accommodating the high voltage cable 12 in a horizontal orientation. In the second example, the tray 42′ is accommodating the high voltage cable 12′ in an inclined orientation. In the third example, the tray 42″ is accommodating the high voltage cable 12″ in a more inclined orientation. The enlarged view of FIG. 7 shows the means 46 to adjust the inclination of the tray 42 along with the tray 42, 42′, 42″ at the three different example inclinations. The high voltage cable 12, 12′, 12″ is omitted in the enlarged view of FIG. 7 for clarity.

[0092] In a step S9, a portion 47 of the support structure 43 is pivoted to change an orientation of the lower part 49 of the high voltage cable 12. The support structure 43 includes means to pivot the portion 47 about a vertical axis 50. In the example of FIG. 7, the portion 47 includes pivotable guiding bars. By pivoting the portion 47 of the support structure 43, the position at which the lower part 49 of the high voltage cable 12 is coming down towards the switch gear 11 is further adjusted.

[0093] In a step S10, the free end 48 of high voltage cable 12 is connected with the switch gear 11.

[0094] FIG. 8 shows the described method steps Si to S10 in a flowchart.

[0095] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0096] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.