METHOD FOR TRANSPORTING A TOWER SECTION, TOWER SECTION, TRANSPORTATION SYSTEM AND METHOD FOR INSTALLING A WIND TURBINE

Abstract

A method for transporting a tower section of a wind turbine, comprising the steps of: providing a tower section which is adapted to be transported in a predetermined transport position, wherein the tower section when in the transport position has a longitudinal axis extending in the horizontal direction and a wall extending along the longitudinal axis, wherein the tower section is adapted to adopt a first vertical height when in an unstressed state in the transport position, applying a deformation force to the wall so as to elastically deform at least one portion of the tower section in such a way that the tower section adopts a second vertical height that is smaller than the first vertical height when in an elastically deformed state in the transport position, and locking the tower section in the elastically deformed state.

Claims

1. A method for transporting a tower section of a wind turbine, the method comprising: A) providing a tower section adapted to be transported in a predetermined transport position, wherein the tower section when in the transport position has a longitudinal axis extending in the horizontal direction and a wall extending along the longitudinal axis, wherein the tower section is adapted to adopt a first vertical height when in an unstressed state in the transport position, B) applying a deformation force to the wall so as to elastically deform at least one portion of the tower section in such a way that the tower section adopts a second vertical height that is smaller than the first vertical height when in an elastically deformed state in the transport position, and C) locking the tower section in the elastically deformed state.

2. The method according to claim 1, further comprising: D) providing a transportation system for retaining and transporting the tower section in the transport position, and/or E) moving the tower section onto the transportation system in the transport position.

3. The method according to claim 2, wherein at least one step chosen from the step D) or the step E) are carried out before step B), such that the deformation force is applied to the wall in the transport position.

4. The method according to claim 1, wherein the wall includes a flowable material and stress induced in the tower section by the deformation force is less than 0.2% proof stress and/or an elastic limit of the flowable material.

5. The method according to claim 4, wherein the stress induced in the tower section by the deformation force is within a range from 40% to 95% of a yield point or the 0.2% proof stress.

6. The method according to claim 1, wherein the tower section has a symmetrical shaped cross-section with a central area, and the deformation force is introduced into the wall of the tower section in a direction of the central area.

7. The method according to claim 1, wherein the wall has two edge regions each having an edge extending in a longitudinal direction and spaced apart from each other in a circumferential direction, and wherein the edges are guided past each other when the tower section is elastically deformed, such that the two edge regions overlap each other when the tower section is in the elastically deformed state.

8. The method according to claim 1, wherein the tower section has a constant cross-section along the longitudinal axis and is elastically deformed along its longitudinal axis in accordance with step B).

9. The method according to claim 1, wherein at least portions of the tower section tapers in such a way that height is a maximum height in the transport position and the tower section is elastically deformed in accordance with step only in a region adjacent to height in the direction of the longitudinal axis.

10. The method according to claim 1, wherein the deformation force is introduced into the wall of the tower section by at least one tensioning system which is coupled to a plurality of corresponding load introducing elements of the tower section.

11. The method according to claim 10, wherein: the tensioning system has a plurality of pull rods each having two coupling sections at respective ends and which are coupled at each of their coupling sections to a corresponding load introducing element of the tower section, wherein the deformation force for elastic deformation is introduced into the load introducing elements and the wall by the pull rods, the tensioning system has a tensioning strap or tensioning cable that is coupled to at least two load introducing elements of the tower section, and wherein the deformation force for elastic deformation is introduced into the load introducing elements and the wall by the tensioning cable.

12. The method according to claim 10, wherein the deformation force for elastic deformation of at least one portion of the tower section is introduced orthogonally to the longitudinal direction by the tensioning system into load introducing elements.

13. The method according to claim 10, wherein the deformation force is introduced by the tensioning system into the corresponding load introducing elements by a motor-driven cable pull or chain hoist or cable winch.

14. The method according to claim 1, further comprising arranging stiffening members in the tower section to brace the tower section in the vertical direction, and wherein the stiffening members are arranged in the tower section before elastic deformation.

15. The method according to claim 1, wherein: the wall has a wall thickness of between 10 mm and 70 mm and height between 4350 mm and 4850 mm, and wherein the elastic deformation of the section of the tower section has a coefficient of deformation that is the ratio of the change in vertical height in the transport position as a result of the elastic deformation to the wall thickness, and the coefficient of deformation is in a range from 1.0 to 55.

16. A tower section for a wind turbine, comprising: a tower section body that is configured to be transported in a predetermined transport position, wherein the tower section body when in the transport position has a longitudinal axis extending in the horizontal direction and a wall extending along the longitudinal axis, wherein the tower section body is adapted to adopt a first vertical height when in an unstressed state in the transport position, wherein the tower section body has a plurality of load introducing elements arranged spaced apart from each other in the direction of the longitudinal axis and configured to be coupled to a tensioning system to apply a deformation force to the wall so as to elastically deform at least a portion of the tower section in such a way that the tower section adopts a second vertical height that is smaller than the first vertical height when in an elastically deformed state in the transport position, and to fix the tower section in the elastically deformed state.

17. The tower section for a wind turbine according to claim 16, wherein: the tower section has a round, oval or polygonal cross-section having an area center, and at least two load introducing elements are fixed inside the wall opposite one another and are adapted to be coupled to each other in pairs by the tensioning system to introduce the deformation force into the wall in the direction of the area center, or the load introducing elements are arranged on the wall in such a way that the deformation force is introduced into the wall eccentrically, that is, in a direction extending at a distance from the area center.

18. The tower section for a wind turbine according to claim 16, wherein the wall includes a steel material.

19. The tower section for a wind turbine according to claim 16, wherein: the wall has two edge regions each having an edge extending in a longitudinal direction and are spaced apart from each other in the circumferential direction, and wherein the edges are designed to be guided past each other during elastic deformation of the tower section such that the two edge regions overlap each other when the tower section is in the elastically deformed state.

20. A transportation system for retaining and transporting the tower section according to claim 16, in a transport position, wherein the tower section when in the transport position has a longitudinal axis extending in the horizontal direction and a wall extending along the longitudinal axis, the transportation system comprising: a first pivot bearing and a second pivot bearing for providing a support surface for a wall of the tower section, wherein the first and second pivot bearings are adapted to retain the tower section in the transport position in an unstressed state in which the tower section adopts a first vertical height, and in an elastically deformed state in which the tower section adopts a second vertical height that is less than the first vertical height.

21. A method for installing a wind turbine at an installation site, method comprising: providing a tower section locked in an elastically deformed state, wherein the tower section is the tower section according to claim 16, relaxing the tower section at the installation site, so that that the tower section adopts an unstressed state with a vertical height of in the transport position, at the installation site, fixing a connector flange to an end portion of the tower section by plate connections, erecting the tower section in such a way that the longitudinal direction is substantially vertical and the connector flange is arranged at the bottom end of the tower section, and joining the tower section by the connector flange to a foundation embedded in the ground of the installation site.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0047] The invention shall now be described in greater detail with reference to preferred embodiments and the attached Figures, in which

[0048] FIG. 1 shows a wind turbine according to a preferred embodiment;

[0049] FIG. 2a shows a perspective view of a tower section in an elastically deformed state according to a first embodiment;

[0050] FIG. 2b shows the tower section of FIG. 2a in a side view;

[0051] FIG. 3a shows a perspective view of a tower section of a wind turbine in an elastically deformed state according to a second preferred embodiment;

[0052] FIG. 3b shows the tower section of FIG. 3a in a side view;

[0053] FIG. 4a shows a perspective view of a tower section of a wind turbine in an elastically deformed state according to a third embodiment;

[0054] FIG. 4b shows the tower section of FIG. 4a in a side view, the deformation force being introduced according to a preferred embodiment;

[0055] FIG. 4c shows the tower section of FIG. 4a in a side view, the deformation force being introduced according to another preferred embodiment;

[0056] FIG. 5 shows a tower section with joining points for load introducing elements according to a first preferred embodiment;

[0057] FIG. 6 shows a portion of the tower section of FIG. 5 with a mounted load introducing element

[0058] FIG. 7 shows a tower section with load introducing elements according to a second preferred embodiment;

[0059] FIG. 8 shows the tower section of FIG. 7 with a tensioning system;

[0060] FIG. 9 shows an connector flange for mounting on a tower section;

[0061] FIG. 10 shows a transportation system for transporting a tower section, in a first preferred embodiment; and

[0062] FIG. 11 shows a transportation system for transporting a tower section, according to a second preferred embodiment.

DETAILED DESCRIPTION

[0063] FIG. 1 shows a wind turbine 100 erected at an installation site, having a tower 102 on which a nacelle 104 is mounted. A rotor arrangement 106 is mounted rotatably on nacelle 104. Rotor arrangement 106 has a rotor hub 110 and rotor blades 108. Rotor arrangement 106 drives a generator (not shown) for generating electric power.

[0064] The tower 102 of wind turbine 100 comprises a tower section 112, 114, 116, and a connector flange 118 (only hinted at in FIG. 1) which is arranged at the bottom end of the tower section and adapted to join the tower section to a foundation embedded in the ground of the installation site, or to a foundation basket.

[0065] FIGS. 2a and b show a tower section 112 according to a first preferred embodiment. As indicated in the Figures, tower section 112 is elastically deformed by applying deformation forces F.sub.1, F.sub.2 in accordance with a method according to a first preferred embodiment.

[0066] Tower section 112 has a wall 120 and a longitudinal axis L, with wall 120 extending along longitudinal axis L. Wall 120 forms the outer surface of the cylindrical tower section 112.

[0067] FIGS. 2a and 2b show tower section 112 in a transport position, in which longitudinal axis L extends substantially in a horizontal direction. As is shown in FIG. 2b, in particular, tower section 112 in the transport position has a vertical height h.sub.1 in the relaxed state. According to the embodiment of tower section 112 shown here, the vertical height h.sub.1 is constant in longitudinal direction L.

[0068] In the present embodiment, tower section 112 has a round cross-section 121 with an area center M, cross-section 121 being constant along longitudinal axis L.

[0069] As FIG. 2b shows, in order to elastically deform at least one portion of tower section 112, deformation forces F.sub.1, F.sub.2 are applied to wall 120 in such a way that, in an elastically deformed state (indicated by the broken lines) in the transport position shown, tower section 112 adopts a second height h.sub.2 that is less than the first vertical height h.sub.1. Deformation forces F.sub.1, F.sub.2 are applied orthogonally to the longitudinal direction L, the effective direction being in the direction of area center M, with the result that cross-section 121 of tower section 112 is deformed into a substantially oval shape. Deformation forces F.sub.1 and F.sub.2 are preferably of equal magnitude and in opposite directions.

[0070] In the manner shown in FIG. 2b, deformation forces F.sub.1, F.sub.2 are applied to wall 120 uniformly and preferably at regular intervals along longitudinal axis L to wall 120 such that tower section 112 is elastically deformed uniformly along longitudinal axis L.

[0071] FIGS. 3a and 3b show a tower section 114 which has been elastically deformed by a method according to a second preferred embodiment.

[0072] Tower section 114 has a wall 120 that extends along the longitudinal axis L, and a cross-section 121, and tapers in portions in such a way that, in the transport position shown, height h.sub.1 is a maximum height from which the vertical height decreases in the direction of the longitudinal axis L.

[0073] In order to deform tower section 114 elastically, deformation forces F.sub.1, F.sub.2 are applied to wall 120 in a locally confined manner in a region which is adjacent to the maximum height h.sub.1 in the direction of the longitudinal axis. Tower section 114 thus deforms elastically only in the region adjacent the maximum height h.sub.1, the vertical height h.sub.1 being reduced thereby to a second vertical height h.sub.2.

[0074] According to the first embodiment, elastic deformation is preferably carried out by deformation forces F.sub.1, F.sub.2 of equal magnitude acting in opposite directions, the effective direction of which is in the direction of area center M. The cross-section 121 shown in the Figure is round in the present case, but it can adopt any shape, wherein a round, oval or polygonal cross-sectional area is to be preferred.

[0075] FIGS. 4a-4cshow the elastic deformation of a tower section 116 by a method according to a third preferred embodiment.

[0076] In FIG. 4a, tower section 116 is shown in a transport position in which tower section 116 has a longitudinal axis L extending in the horizontal direction, a vertical height, and a wall 120 extending along the longitudinal axis. In the unstressed state in the transport position, tower section 116 has a constant maximum height h.sub.1. The tower section also has a cross-section 121 orthogonal to the longitudinal direction L and with an area center M.

[0077] Wall 120 has two edge regions 122 that each have an edge 124 extending in a longitudinal direction L and which are spaced apart from each other in the circumferential direction.

[0078] In the method in the embodiment shown, edges 124 are guided past each other to elastically deform section 116, such that edge regions 122 overlap each other in the elastically deformed state of tower section 116, as indicated in FIGS. 4a-4c.

[0079] According to the embodiment shown in FIG. 4b, deformation forces F.sub.1, F.sub.2, which are preferably of the same magnitude and act in opposite directions, are applied to wall 120 in such a way, in order to elastically deform tower section 116, that their effective direction is in the direction of the area center M of cross-section 121. The elastic deformation of tower section 116 causes area center M to be displaced, and forces F.sub.1, F.sub.2 follow the displacement of area center M, with the result that their effective direction is still at least approximately in the direction of the displaced area center M′.

[0080] The deformation of tower section 116 as shown in FIG. 4c differs from the embodiment shown in FIG. 4b in that a deformation force F is applied eccentrically to wall 120 in edge region 122, i.e., with an effective direction that is spaced apart from area center M. Compared to the embodiment shown in FIG. 4b, this has the advantage that a reduced deformation force F is sufficient for elastic deformation of tower section 116.

[0081] According to FIGS. 4b and 4c, wall 120 is deformed thereby in such a way that it curls into a spiral or helical shape in the side view.

[0082] If a tower section 116 according to FIGS. 4a-4c is provided, it is also necessary, before erecting the wind turbine 100 according to FIG. 1, to join edges 124 to each other along the entire longitudinal axis L of tower section 116 before attaching tower section 116 to connector flange 118.

[0083] FIG. 5 shows tower section 112 in an unstressed state. Tower section 112 has a number of joining points 126 spaced apart from each other in the longitudinal direction L in wall 120. Joining points 126 are adapted to be coupled to corresponding load introducing elements 128, 129 (cf. FIGS. 6, 7 and 8) for applying a deformation force F to wall 120. Joining points 126 are provided in the form of holes and in the transport position are arranged in the region of the maximum vertical height of tower section 112.

[0084] FIG. 6 shows an example of a load introducing element in the form of a bolt arrangement 128 comprising a number of bolts 128a and a number of corresponding securing members 128b for securing bolts 128a. As FIG. 5, in particular, shows, bolts 128a are each engaged with a joining point 126 provided in the form of a hole in wall 120. Bolt 128a is secured by securing member 128b in hole 126. Securing member 128b is provided in the form of a nut.

[0085] The distance in longitudinal direction L between the individual load introducing elements 128a and hence also between the corresponding joining points 126 is dependent on the wall thickness t and the maximum height h.sub.1 of tower section 112.

[0086] For example, if the stress induced by deformation force F is no more than 300 N/m.sup.2, the wall thickness t is 60 mm and the elastic deformation as a result of applying a deformation force F in the direction of area center M, preferably 13 evenly distributed load introducing elements per meter are attached to wall 120.

[0087] Load introducing elements 128a can be coupled to each other preferably by means of pull rods or a strap or cable in order to apply the elastic deformation force. The deformation force F to be applied depends on the wall thickness t of wall 120 and the yield point or the 0.2% proof stress of the material being used and which the wall at least partly includes.

[0088] After tower section 112 has been relieved of stress or load at the installation site following transportation, load introducing elements 128a preferably remain in joining points 126 in order to reduce any weakening of tower section 112 as a result of the notch stresses.

[0089] FIGS. 7 and 8 show a tower section 112 with load introducing elements 129 according to a second preferred embodiment.

[0090] This embodiment differs from the embodiment shown in FIG. 6 in that load introducing elements 129 are thermally joined, preferably welded, to the inner side of wall 120 without any additional joining point. Load introducing elements 129 are provided in the form of metal sheets or plates with an edge extending substantially in the direction of longitudinal axis L, and which are joined thermally to the inner side of wall 120. Load introducing elements 129 have recesses 131 which are preferably cylindrical and with which tensioning systems can be brought into engagement in order to apply a deformation force F to wall 120.

[0091] As shown in FIG. 8, in particular, recesses 131 can be coupled to a tensioning system comprising a tensioning cable 130 and a cable winch or chain hoist 132 that is only outlined in FIG. 8.

[0092] Tensioning cable 130 is adapted to couple each of the load introducing elements 129 spaced apart in longitudinal direction L and arranged substantially in a row to at least one corresponding load introducing element 129 arranged spaced apart and substantially in a row in longitudinal direction L on the opposite wall. A first load introducing element 129 is preferably coupled by means of a tensioning cable 130 to only one opposite load introducing element 129, with each of the following load introducing elements 129 being coupled to two load introducing elements 129 on the opposite wall, such that tensioning cable 130 is tensioned between the opposite portions of wall 120 and engages alternately with a respective load introducing element 129. The last load introducing element in an edge portion of tower section 112 is coupled to only one opposite load introducing element 129 and is adapted to guide tensioning cable 130 in such a way that it engages with cable winch or chain hoist 132 to apply a deformation force F to each of load introducing elements 129. The tower section is subsequently relieved of stress or load at the installation site in a preferably controlled manner by means of such a cable winch or chain hoist.

[0093] Tower section 112 preferably comprises a plurality of tensioning systems that preferably have a tensioning cable 130 or tensioning strap and that can each be brought into engagement with some of the available load introducing elements 129 in the respective portion in order to apply a deformation force F to wall 120. A plurality of tensioning systems are thus used to allow deformation force F to be introduced more evenly into the respective load introducing elements 129 coupled thereto. The same also applies to the embodiment shown in FIG. 6.

[0094] The load introducing elements 128, 129 shown in FIGS. 6-8 can also be attached to a different position on wall 120, for example to allow force to be applied eccentrically so as to elastically deform tower section 112 (cf. FIGS. 4a and 4c).

[0095] FIG. 9 shows a perspective view of a connector flange 118 in a partly cutaway view. Connector flange 118 has a T-shaped cross-section 134 and comprises a base plate 136 and a web 138. Base-side holes 140 are arranged in the region of base plate 136. Base-side holes 140 are designed to connect connector flange 118 to a foundation or to a foundation basket at the installation site. Web 138 is preferably narrower in relation to base plate 136, the thickness of web 138 preferably being adapted to the wall thickness t (cf. FIG. 6) of the respective steel tower section 112, 114, 116.

[0096] In the region of web 138, connector flange 118 also has a number of tower-side holes 142 that are distributed spaced apart from each other along the circumference of connector flange 118. Tower-side holes 142 are designed to be brought into engagement with two guide plates 144a, b. The first guide plate 144a is disposed on an inside wall of web 138 and partly overlaps the web such that web 138 engages with tower-side holes 142 and the corresponding holes of guide plate 144a. The second guide plate 144b is disposed on the outwardly facing side of web 138 and partly overlaps web 138 in such a way that the holes of guide plate 144b are in alignment with the corresponding tower-side holes 142 of web 138 and can be brought into engagement therewith by means of bolt or screw connections. Guide plates 144a, b are arranged parallel to each other in such a way that a gap is formed between them with a thickness that is substantially equal to the wall thickness t (cf. FIG. 6) of tower section 112, 114, 116. To mount tower sections 112, 114, 116 (not shown, cf. FIGS. 2a-8) on connector flange 118, an end portion of tower section 112, 114, 116 can be guided into the gap formed between guide plates 144a, b and joined by means of a bolt or screw connection to the upper connection holes 146 of guide plates 144a, b. Tower section 112, 114, 116 can be arranged in the gap in such a way that the connection holes (not shown) at the end portion of tower section 112, 114, 116 and the connection holes 146 of guide plates 144a, b are aligned with each other. Bolts or screws can then be passed through connection holes 146 to join connector flange 118 to tower section 112, 114, 116 by a combination of bolting and clamping.

[0097] FIGS. 10 and 11 show the transportation system 148, which in FIG. 10 retains a tower section 112 according to a first preferred embodiment and in FIG. 11 a tower section 116 according to a third preferred embodiment in a transport position. In FIGS. 10 and 11, tower sections 112, 116 are retained in the transport position in an elastically deformed state in which they adopt vertical height h.sub.2, which is less than height h.sub.1 in a relaxed state of the respective tower section 112, 116.

[0098] To that end, transportation system 148 has a first and a second pivot bearing 150a, b, each of which is designed to provide a support surface 152 for a portion of wall 120 of tower section 112, 116. Support surfaces 152 come into contact with an area of wall 120.

[0099] By means of the two pivot bearings 150a, b, support surfaces 152 can be pivoted about a pivot point 154 of the pivot bearing so that the respective tower sections 112, 116 can be retained not only in a relaxed, unstressed state, but also in an elastically deformed state in the transport position.

LIST OF REFERENCE SIGNS

[0100] 100 Wind turbine

[0101] 102 Tower

[0102] 104 Nacelle

[0103] 106 Rotor arrangement

[0104] 108 Rotor blades

[0105] 110 Rotor hub

[0106] 112, 114, 116 Tower section

[0107] 118 Connector flange

[0108] 120 Wall

[0109] 121 Cross-section

[0110] 122 Edge regions

[0111] 124 Edge

[0112] 126 Joining point

[0113] 128 Bolt arrangement

[0114] 128a Bolt

[0115] 128b Securing member

[0116] 129 Steel plates

[0117] 130 Tensioning system, tensioning cable

[0118] 131 Recesses

[0119] 132 Cable winch, chain hoist

[0120] 134 T-shaped cross-section

[0121] 136 Base plate

[0122] 138 Web

[0123] 140 Base-side holes

[0124] 142 Tower-side holes

[0125] 144a, b Pair of guide plates

[0126] 146 Connection holes

[0127] 148 Transportation system

[0128] 150a, b First and second pivot bearings

[0129] 152 Support surface

[0130] 154 Pivot point

[0131] F, F.sub.1, F.sub.2 Deformation force

[0132] L Longitudinal axis

[0133] h.sub.1 First vertical height

[0134] h.sub.2 Second vertical height

[0135] M Area center

[0136] The various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.