Supporting column for wind power station

Abstract

A support column (1) for a wind power plant. The support column comprises an elongate body (5) configured to hold the wind turbine in a raised position or to transfer rotational energy to a rotor of the wind turbine. The elongated body comprises: a central structure (10) configured to provide structural stability to the support post; and a protective layer (20) on the central structure, the protective layer configured to protect the central structure from interaction with the ambient environment. The central structure mainly comprises a biologically derived fibrous composition and the protective layer comprises at least one rigid plate (22) arranged to be attached in a prestressed manner to at least an outer surface of the central structure.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of support column for wind power station, in particular to a kind of support column for offshore wind power station.Support column includes long body, the long body is configured to keep wind turbine at elevated position, and / or alternatively, support column is connected to turbine rotor shaft and long body transmits rotary energy to generator.Long body includes central structure, the central structure is configured to provide structural stability to support column for keeping wind turbine or for transmitting rotary energy to the rotor of wind turbine.Support column further includes protective layer on central structure, the protective layer is configured to protect central structure from the interaction of central structure with surrounding environment.

[0002] The utility model further relates to a kind of method for establishing support column for wind power station and the use of this support column for wind power station. BACKGROUND

[0003] Wind power station uses different types of support column, for keeping wind turbine with wind blade, for example horizontal axis wind turbine (HAWT) at elevated position, or for keeping wind blade and transmitting rotary energy to the rotor of wind turbine, for example so-called vertical axis wind turbine (VAWT) by support column.

[0004] Support column can have considerable height, for example several hundred meters. Even height up to 400 meters is proposed. In order to provide sufficient structural stability, support column of prior art usually uses various special materials, for example fiber reinforced polymer, carbon fiber, etc. Although sufficient strength is provided, the problem of these materials is that they are expensive and significantly increase the total cost of wind power station.

[0005] In order to reduce the cost of support column, alternative materials can be used, for example various bio-derived fiber compositions. In particular, laminated wood has shown to provide excellent performance as structural material, and laminated wood can have higher strength-to-weight ratio compared to concrete and steel material. The problem of such bio-derived fiber compositions is to avoid structural strength deterioration due to the influence of surrounding environment, for example due to moisture intrusion into the material of support column. This problem is particularly evident when using support column in offshore environment.

[0006] Another problem of support column of prior art is how to assemble multiple segments into support column with significant height.

[0007] WO2008153489 (A1) discloses an example of wooden support column for wind power unit.

[0008] CN 206220559 U discloses a fiber cloth for prestressed reinforcement of a pole, relating to the technical field of wood. CN 205936983 U discloses a thick bamboo cylinder section with prestressed concrete outside, comprising a tower section of thick bamboo cylinder body. WO 2008 / 153489 A1 discloses a wind power unit, wherein the material of the support column is essentially wood. CN 217421428 U discloses a prestressed concrete-wood combined wind-driven generator tower cylinder. CN 211201336 U relates to a multidirectional prestressed cylindrical orthotropic laminated wood structure wind power tower. Utility model content

[0009] It is an object of the utility model to provide an improved support column for a wind power plant. In particular, it is a first object of the utility model to provide an improved support column that reduces the deterioration of the structural strength of a bio-derived fiber composition used in the support column. It is a second object of the utility model to provide an improved support column that is easy to assemble. It is a third object of the utility model to provide an improved method for assembling a support column.

[0010] These objects are achieved by a support column for a wind power plant, wherein the support column comprises an elongated body configured to hold a wind turbine in an elevated position and / or to transfer rotational energy to a rotor of the wind turbine. The body comprises a central structure configured to provide structural stability to the support column and a protective layer on the central structure configured to protect the central structure from interaction with the surrounding environment.

[0011] The central structure mainly comprises a bio-derived fiber composition, and wherein the protective layer comprises at least one rigid plate arranged to be attached to at least an outer surface of the central structure in a prestressed manner.

[0012] By attaching the protective layer to at least an outer surface of the central structure in a prestressed manner, the outer surface can be protected from moisture intrusion into the bio-derived fiber composition. Furthermore, the prestressed state of the rigid plate enables the fibers in the bio-derived fiber composition to be held in place, thereby ensuring that the structural stability of the support column is maintained.

[0013] The term "bio-derived fiber composition" is to be understood as a material derived from a biological source material, excluding fossil materials or materials embedded in geological formations. The composition further comprises fibers that contribute to its structural strength.

[0014] The protective layer has the function of protecting the central structure from interaction with the surrounding environment. The protective layer is in particular a layer having water-repellent properties. The protective layer comprises at least one rigid plate which is composed of a material having shape stability, thereby ensuring that the protective layer remains attached to the central structure in a pre-stressed state during use of the support column.

[0015] According to an embodiment of the present application, the rigid plate of the protective layer mainly comprises one of an aluminum alloy, a glass fiber reinforced plastic, a thermoplastic, a stainless steel or a combination thereof. Although the protective layer can comprise an expensive special material, the amount of the protective layer is small relative to the extent of the central structure and only a small part of the total cost of the support column.

[0016] According to an embodiment of the present application, the protective layer has a thickness in the interval of 1 mm to 50 mm, preferably the protective layer has a thickness in the interval of 2 mm to 10 mm.

[0017] According to an embodiment of the present application, the central structure has a circular outer surface. Preferably, the central structure has a circular outer surface with an inner wall diameter of 1 m to 30 m, preferably 2 m to 21 m.

[0018] According to an embodiment of the present application, the at least one rigid plate of the protective layer is attached to the central structure by one of a glue joint and a bolt joint or a combination thereof.

[0019] By providing the glue at a high temperature, for example at a temperature between 20 °C to 50 °C, the glue is adapted to form a pre-stressed manner of adhesion between the rigid plate and the central structure. The glue is for example an epoxy resin.

[0020] According to an embodiment of the present application, the bio-derived fiber composition mainly comprises one of a wood material, bamboo, straw, cotton, reed, hemp fiber, flax or a combination thereof. These materials have the advantage of providing a high strength to weight ratio while being cost effective.

[0021] According to an embodiment of the present application, the wood material mainly comprises a glued laminated wood, for example a glued laminated wood mainly comprising spruce. The laminated wood has the advantage of providing a high strength to weight ratio while being cost effective.

[0022] According to an embodiment of the present application, the protective layer comprises two or more rigid plates which are joined by friction stir welding. Friction stir welding is particularly suitable for joining rigid plates of aluminum alloys.

[0023] According to an embodiment of the utility model, the protective layer is attached to the central structure in a prestressed manner in the interval of 5MPa to 100MPa, preferably in the interval of 10MPa to 30MPa at the working temperature of the support column. The working temperature is usually in the interval of -10 DEG C to 30 DEG C.

[0024] According to an embodiment of the utility model, the elongated body comprises an opening extending along the longitudinal axis of the body and defining an inner surface of the central structure, wherein the protective layer is arranged to the inner surface of the central structure. The opening defines a hollow interior space of the support column. The hollow interior space can be used for wiring, etc.

[0025] According to an embodiment of the utility model, the wall thickness of the central structure is in the interval of 5cm 2 to 200cm 2 .

[0026] According to an embodiment of the utility model, the rigid plates of the protective layer are wound in a spiral form on the central structure. By winding the protective layer in a spiral form, the protective layer can be provided by a roll that holds the rigid plates, which facilitates the process of applying the rigid plates and attaching them to the central structure in a prestressed manner.

[0027] According to an embodiment of the utility model, the elongated body comprises 2 to 12 body segments, preferably the elongated body comprises 3 body segments, each body segment having two end sides and two long sides, wherein the body segments are attached together at the long sides of the body segments so that they jointly form a circumferential portion of the body.

[0028] According to an embodiment of the utility model, the elongated body comprises three elongated body segments, each elongated body segment having two end sides and two long sides, wherein the body segments are attached together at the long sides of the body segments so that the body segments jointly form a circumferential portion of the body. By attaching the three elongated body segments together so that they jointly form a circumferential portion of the elongated body, a rigid attachment between the segments is obtained.

[0029] According to an embodiment of the utility model, the three elongated body segments are arranged as respective truss assemblies, each truss assembly comprising a hollow interior between the outer surface and the inner surface and one or more support beams extending between the outer surface and the inner surface. The truss assemblies have the advantage of providing an improved strength-to-weight ratio.

[0030] According to an embodiment of the utility model, the truss assemblies are arranged with a convex outer surface and alignment parts configured to abut and connect to the respective truss assemblies so that they jointly form a circumferential portion of the central structure. By the alignment parts, the positioning and joining of the body segments is facilitated.

[0031] According to an embodiment of the utility model, the three elongated body segments are completely enclosed in a protective layer. By completely enclosing the body segments, handling of the body segments is facilitated. For example, the body segments can be stored externally, exposed to weather, before assembling the body segments into a support column.

[0032] According to an embodiment of the utility model, the three body segments have a tapering outer surface, such that they together form a conical outer surface in the direction of the elongated extension of the support column.

[0033] According to an embodiment of the utility model, the body segments comprise first attachment means connecting the body segments together along the long sides of the body segments, wherein the first attachment means comprise tongue-and-groove joints. The tongue-and-groove joints of the first attachment means can preferably be reinforced with one of a glue joint and a bolt joint or a combination thereof.

[0034] According to an embodiment of the utility model, the body segments comprise second attachment means attaching the body segments together along the short sides of the body segments, wherein the second attachment means comprise tongue-and-groove joints. The tongue-and-groove joints of the second attachment means can preferably be reinforced with one of a glue joint and a bolt joint or a combination thereof.

[0035] According to an embodiment of the utility model, the body segments comprise a first type of segment, a second type of segment and a third type of segment, wherein the length of the third type of segment is one third of the first type of segment and the length of the second type of segment is two thirds of the first type of segment, wherein the body is compiled connecting the end sides and the long sides of the first type of segment, the second type of segment and the third type of segment such that the connection of the end sides between two body segments is located at the long sides of the further two body segments forming a circumferential portion.

[0036] By the configuration of the first type of segment, the second type of segment and the third type of segment, the elongated body is compiled such that the connection of the end sides is located at the long sides of the further two segments forming a circumferential portion of the elongated body. Thereby, the connection strength between the segments is improved and the overall strength of the elongated body is improved.

[0037] The utility model also aims at a method for establishing a support column for a wind power plant, wherein the support column comprises an elongated body configured to hold a wind turbine in an elevated position or to transfer rotational energy to a rotor of the wind turbine, wherein the method comprises the following steps:

[0038] - preparing at least one body segment of the elongated body by:

[0039] i) forming a central structure, the central structure mainly comprising a bio-derived fibre composition; and ii) attaching a protective layer comprising at least one rigid plate to at least an outer surface of the central structure in a pre-stressed manner.

[0040] According to embodiments of the present application, the step of attaching the protective layer in a pre-stressed manner comprises forming one of a glue joint and a bolt joint or a combination thereof.

[0041] According to embodiments of the present application, the step of attaching the protective layer in a pre-stressed manner comprises:

[0042] - attaching two or more rigid plates to the central structure, and

[0043] - joining the two or more rigid plates together, for example by friction stir welding.

[0044] According to embodiments of the present application, the method comprises:

[0045] - positioning the rigid plates of the protective layer to the central structure by winding the protective layer in a spiral form on the central structure.

[0046] According to embodiments of the present application, the method comprises:

[0047] - preparing three body segments of an elongated shape having two end sides and two long sides by:

[0048] i) forming a central structure for the body segments, the central structure mainly comprising a bio-derived fibre composition, and

[0049] ii) attaching a protective layer comprising at least one rigid plate to at least an outer surface of the central structure in a pre-stressed manner, such that the fibres of the fibre composition are held in place, and

[0050] - connecting the three body segments of an elongated shape together at their long sides such that they jointly form a circumferential portion of the body.

[0051] According to embodiments of the present application, the method comprises:

[0052] - preparing a first type of segment, a second type of segment and a third type of segment, wherein the length of the third type of segment is one third of the first type of segment, the length of the second type of segment is two thirds of the first type of segment, and

[0053] - connecting the end sides and the long sides of the first type of segment, the second type of segment and the third type of segment such that the connection of the end sides between two body segments is located at the long sides of the other two body segments forming the circumferential portion.

[0054] By using the support column according to any one of the above embodiments of the present application, the object of the present application is further achieved.

[0055] According to the embodiment of the present application, the support column is used for holding a structural component of a wind power plant at an elevated position.

[0056] According to the embodiment of the present application, the support column is used for transferring rotational energy to a turbine of a wind power plant. BRIEF DESCRIPTION OF DRAWINGS

[0057] Embodiments of the present application will now be described, by way of example only, with reference to the following drawings:

[0058] Figure 1 a side view of a support column for a wind power plant according to an embodiment of the present application is shown,

[0059] Figure 2a a cross section of a support column according to an embodiment of the present application is shown,

[0060] Figure 2b a cross section of a support column according to another embodiment of the present application is shown,

[0061] Figure 3a a side view of a support column according to an embodiment of the present application is shown, wherein the support column comprises connected segments,

[0062] Figure 3b a cross section of a body segment in the form of a truss assembly according to an embodiment of the present application is shown,

[0063] Figure 3c a cross section of three body segments joined together according to an embodiment of the present application is shown, Figure 3b

[0064] Figure 3d a side perspective view of Figure 3c is shown,

[0065] Figure 3e a side perspective view of a body segment in Figure 3b is shown,

[0066] Figure 3f a side perspective view of another body segment is shown,

[0067] Figure 4a a side view of a configuration of body segments for assembling a support column according to an embodiment of the present application is shown,

[0068] Figure 4b a cross section of a body segment for assembling a support column according to an embodiment of the present application is shown,​Figure 4a three types of body sections of the support column,

[0069] Figure 5a a flow chart of a method for establishing a support column according to an embodiment of the utility model is shown,

[0070] Figure 5b a flow chart of a method for establishing a support column according to another embodiment of the utility model is shown, and

[0071] Figure 5c a flow chart of a method for establishing a support column according to yet another embodiment of the utility model is shown. DETAILED DESCRIPTION

[0072] With reference to Figure 1 , a side view of a support column 1 for a wind power plant according to an embodiment of the utility model is shown. The support column 1 comprises an elongated body 5 which is configured to be arranged in an upright position. The elongated body 5 is further configured to hold a wind turbine in an elevated position. The elongated body 5 is further configured to transfer rotational energy to a rotor of the wind turbine. Thus, the elongated body 5 has a structural strength for this purpose.

[0073] The elongated body 5 comprises a central structure 10 which is configured to provide such structural stability to the support column 1. The central structure 10 mainly comprises a bio-derived fiber composition, preferably one of a wood material, bamboo, straw, cotton, reed, hemp fiber, flax or a combination thereof. Such a material has the advantage of having a high strength to weight ratio while being cost effective. Preferably, the central structure 10 uses a wood material mainly comprising glued laminated timber.

[0074] The elongated body 5 further comprises a protective layer 20 on the central structure 10 which is configured to protect the central structure 10 from interaction with the surrounding environment. The protective layer 20 in particular has water repellent properties. The protective layer 20 is arranged at least on the outer surface of the central structure 10. Preferably, the protective layer 20 is arranged to completely enclose the central structure 10.

[0075] The protective layer 20 further comprises at least one rigid plate 22 which is arranged to be attached to the central structure 10 in a pre-stressed manner such that the fibers of the fiber composition are held in place. Thus, the strength of the elongated body 5 is maintained during use of the support column 1.

[0076] The rigid plates 22 are preferably attached to the central structure 10 with a pre-stress in the interval of 5 MPa to 100 MPa, preferably in the interval of 10 MPa to 30 MPa. The attachment is such that the pre-stress interval is maintained at the working temperature of the support column 1.

[0077] The rigid plates 22 of the protective layer 20 preferably comprise mainly one of an aluminium alloy, a glass fibre reinforced plastic, a thermoplastic, a stainless steel or a combination thereof. In particular, aluminium alloys have an advantage in terms of cost-weight strength ratio.

[0078] In the disclosed embodiment, the protective layer 20 comprises a plurality of rigid plates 22 which are arranged adjacent to each other and are joined together at the connection 24, for example by friction stir welding. In particular, the rigid plates 22 in the form of aluminium alloys have proven advantageous for joining by friction stir welding.

[0079] In an alternative embodiment, the rigid plates 22 of the protective layer 20 are wound in a spiral on the central structure 10. The number of necessary joining pieces is thereby reduced. Furthermore, the application of the protective layer 20 is also more convenient, since the rigid plates 22 can be stored and provided by a coil which holds the rigid plates 22.

[0080] In a preferred embodiment of the utility model, the thickness of the protective layer 20 is in the interval of 1 mm to 50 mm, preferably in the interval of 2 mm to 10 mm. This thickness has proven to be sufficient to protect the central structure 10 from moisture ingress. Furthermore, this thickness is sufficient for the proposed rigid plates 22 to maintain the pre-stressed attachment to the central structure 10 during use of the support column 1.

[0081] The rigid plates 22 are preferably attached to the central structure 10 by one or a combination of a glue joint and a bolt joint. Preferably, the glue is applied at an elevated temperature, for example at a temperature above 20°C. Thus, the pre-stressed attachment is provided after curing of the glue. The glue is for example an epoxy resin. The pre-stressed attachment can preferably be supported by the bolt joint.

[0082] Reference is made to Figure 2a which shows a cross section of a support column 1 according to an embodiment of the utility model. The protective layer 20 is attached to the outer and inner surface of the central structure 10. Furthermore, a plurality of rigid plates 22 are joined together at the connection 24 to form the protective layer 20. In Figure 2a , four schematic rigid plates 22 are shown attached in a pre-stressed manner on the outer surface.

[0083] Reference is made toFigure 2b The diagram shows a cross-section of a support column 1 according to another embodiment of the present invention. The elongated body 5 is composed of three body segments 50. Each of the three body segments 50 has two end portions and two long sides. The three body segments 50 are attached together at their long sides, such that the three body segments together form the circumferential portion of the body 5.

[0084] The three body segments 50 include a first attachment device 52 that attaches the body segments 50 together along their long sides. Preferably, the first attachment device 52 includes a tongue-and-groove type engagement member.

[0085] In the disclosed embodiment, each of the three body segments 50 has a protective layer 20 on both its outer and inner surfaces. However, the three body segments 50 lack a protective layer 20 on their long sides, where the body segments 50 are attached via a first attachment device 52. In an alternative embodiment, each of the three body segments 50 has a protective layer 20 on all its sides, thereby completely surrounding the central structure 10 of each body segment 50.

[0086] refer to Figure 3a A side view of the support column 1 according to an embodiment of the present invention is shown. Figure 3a The diagram schematically illustrates an embodiment of the support column 1, wherein the elongated body 5 includes a body segment 50, which is connected at its long side by a first attachment device 52 and at its short side by a second attachment device 54.

[0087] refer to Figures 3b to 3e The following embodiments of the present invention are disclosed: the elongated body 5 is assembled from three elongated body segments 50 in the form of corresponding truss components. Figure 3b The image shows a cross-section of one segment. Figure 3c The image shows a cross-section of the three body segments 50 joined together. Figure 3d It shows Figure 3c A side perspective view of the support column 1 in the diagram. Figure 3e It shows Figure 3b A side perspective view of the main body segment 50. Figure 3f It shows Figure 3a A side perspective view of another body section 50 used in this study.

[0088] The truss assembly includes a hollow interior located between the outer and inner surfaces of the elongated body 5. The truss assembly also includes beams 62 located between the outer and inner surfaces of the elongated body 5. In the disclosed embodiment, three beams 62 are shown. However, it should be understood that other numbers of beams 62 may be used. The beams 62 serve to improve the structural stability of the body segment 50.

[0089] The truss assembly further comprises alignment portions 64, see Figure 3b . The alignment portions 64 are configured to abut and connect with the respective truss assembly such that the alignment portions 64 collectively form the circumferential portion of the elongated body 5, as shown in Figure 3c .

[0090] In the disclosed embodiment of the utility model, each of the body segments 50 is completely surrounded by the protective layer 20. However, it is understood that alternatively only the outer surface of each body segment 50 is provided with the protective layer 20. In Figure 3b , Figure 3c , the protective layer 20 is indicated by a dashed line.

[0091] In the disclosed embodiment of the utility model, the outer surface is convex, while the inner surface is flat. When the body segments 50 are joined together, the outer surfaces of the body segments 50 form the circumferential portion of the elongated body 5. In the disclosed embodiment, the elongated body has a circular circumferential portion.

[0092] In the preferred embodiment of the utility model, the three body segments 50 have an outer surface tapering in its longitudinal extension. Thus, when the three body segments 50 are joined together, they collectively form an outer surface tapering in its extension direction.

[0093] With reference to Figure 4a , a side view of a configuration of body segments 50 for assembling a support column 1 according to an embodiment of the utility model is shown. The body segments 50 comprise a first type segment 50a, a second type segment 50b and a third type segment 50c, see Figure 4b . The three body segments 50 are such that the length of the third type segment 50c is one third of the length of the first type segment 50a and the length of the second type segment 50b is two thirds of the length of the first type segment 50a.

[0094] The three body segments 50 are configured to be assembled such that they collectively form the circumferential portion of the support column 1 and are stacked on top of each other to collectively form the height of the support column 1. Furthermore, the three body segments 50 are configured to be assembled such that the connection of the end side portion between two body segments 50 is located at the long side portion of the other two body segments 50 forming the circumferential portion.

[0095] This is shown in Figure 4aare shown in Fig. 2, wherein the left-hand column of segments comprises from the bottom a third type segment 50c, followed by two first type segments 50a. The middle column of segments comprises from the bottom a second type segment 50b, followed by a first type segment 50a, and followed by a second type segment 50b. The right-hand column of segments comprises from the bottom two first type segments 50a, followed by a third type segment 50c. Hence, the connection of the end side is always at the long side of two further body segments 50 in the adjacent column. Thereby, the overall strength of the support column 1 is improved.

[0096] Referring to Figure 5a Fig. 6, a flow chart of a method for establishing a support column 1 according to an embodiment of the utility model is disclosed.

[0097] The method comprises in step 110 preparing at least one body segment 50 of an elongated body 5, forming in step 120 a central structure 10 comprising mainly a bio-derived fiber composition, and attaching in step 130 a protective layer 20 comprising at least one rigid plate 22 to at least an outer surface of the central structure 10 in a pre-stressed manner such that the fibers of the fiber composition are held in place.

[0098] The at least one body segment 50 can be completely or partially attached with the protective layer 20. The step of attaching the protective layer 20 in a pre-stressed manner preferably comprises forming one or a combination of a glue joint and a bolt joint. Step 130 can also comprise attaching two or more rigid plates 22 to the central structure 10 and joining the plates 22, for example by friction stir welding. Step 130 can also comprise winding the rigid plates 22 onto the central structure 10 in a helical manner.

[0099] Referring to Figure 5b Fig. 7, a flow chart of a method for establishing a support column 1 according to another embodiment of the utility model is disclosed. The method comprises in step 110 preparing three elongated body segments 50 having two end side and two long sides, forming in step 120 a central structure 10 for the body segments 50, the central structure 10 comprising mainly a bio-derived fiber composition, and attaching in step 130 a protective layer 20 comprising at least one rigid plate 22 to at least one outer surface of the central structure 10 in a pre-stressed manner such that the fibers of the fiber composition are held in place. The method further comprises in step 140 connecting the three elongated body segments 50 together at their long sides such that they jointly form a circumferential portion of the elongated body 5.

[0100] Referring to Figure 5c Fig. 8, a flow chart of a method for forming a support column 1 according to another embodiment of the utility model is disclosed. The method is similar to the method of Fig. 6, and the steps of the method of Fig. 6 are indicated by the same reference numerals as in Fig. 6. The method of Fig. 8 differs from the method of Fig. 6 in that the method of Fig. 8 comprises in step 150 connecting the three elongated body segments 50 together at their end sides such that they jointly form an end side of the elongated body 5. Figure 5bThe difference between the embodiment in Fig. 1 and the embodiment in Fig. 2 is that the step 110 of producing three elongated body sections 50 further comprises producing a first type section 50a, a second type section 50b and a third type section 50c, wherein the length of the third type section 50c is one third of the length of the first type section 50a and the length of the second type section 50b is two thirds of the length of the first type section 50a. The method differs from the method in Fig. 1 in that the step 140 comprises connecting the end sides and the long sides of the first type section 50a, the second type section 50b and the third type section 50c such that the connection of the end sides between two body sections 50 is located at the long side of the adjacent body section 50 forming a circumferential portion. Figure 5b The difference between the embodiment in Fig. 1 and the embodiment in Fig. 2 is that the step 110 of producing three elongated body sections 50 further comprises producing a first type section 50a, a second type section 50b and a third type section 50c, wherein the length of the third type section 50c is one third of the length of the first type section 50a and the length of the second type section 50b is two thirds of the length of the first type section 50a. The method differs from the method in Fig. 1 in that the step 140 comprises connecting the end sides and the long sides of the first type section 50a, the second type section 50b and the third type section 50c such that the connection of the end sides between two body sections 50 is located at the long side of the adjacent body section 50 forming a circumferential portion.

[0101] In an embodiment of the application, the support column 1 is used to hold a structural component of a wind power plant, for example a wind turbine with a wind blade, in an elevated position. In an alternative embodiment of the application, the support column 1 is used as a shaft for transmitting rotational energy to a turbine of a wind power plant. In another embodiment of the application, the first and second support columns 1 are used to counter-rotate a wind power plant.

[0102] It should be noted that the above-described embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

[0103] For example, it will be appreciated that embodiments of the application can be applied independently of the features of the central structure being composed of a bio-derived fibre composition and independently of the features relating to the protective layer on the central structure.

Claims

1. A support column for a wind power plant, wherein The support column (1) comprises an elongated body (5) configured to hold a wind turbine in an elevated position and / or to transfer rotational energy to a rotor of the wind turbine, wherein the elongated body (5) comprises: - a central structure (10) configured to provide structural stability to the support column (1), and - a protective layer (20) on the central structure (10) configured to protect the central structure (10) from interaction with the surrounding environment, characterized in that: the central structure (10) comprises a bio-derived fiber composition, and wherein the protective layer (20) comprises at least one rigid plate (22) arranged to be attached to at least an outer surface of the central structure (10) in a pre-stressed manner.

2. The support column of claim 1, wherein, The rigid plate (22) of the protective layer (20) consists of one of an aluminum alloy, a glass fiber reinforced plastic, a thermoplastic, a stainless steel.

3. Support column according to claim 1 or 2, characterized in that The protective layer (20) has a thickness in the interval of 1 mm to 50 mm.

4. The support column according to claim 1 or 2, characterized in that The protective layer (20) has a thickness in the interval of 2 mm to 10 mm.

5. The support column according to claim 1 or 2, characterized in that At least one of the rigid plates (22) is attached to the central structure (10) by one of a glue joint and a bolt joint or a combination thereof.

6. The support column of claim 1 or 2, wherein, The bio-derived fiber composition comprises a wood material.

7. The support column of claim 6, wherein, The wood material comprises a glued laminated wood.

8. The support column of claim 7, wherein, The glued laminated wood is a glued laminated wood comprising spruce.

9. The support column of claim 1 or 2, wherein, The protective layer (20) comprises two or more rigid plates (22) which have been joined by friction stir welding.

10. The support column of claim 1 or 2, wherein, The protective layer (20) is attached to the central structure (10) in a pre-stressed manner at a working temperature of the support column (1) in the interval of 5 MPa to 100 MPa.

11. The support column of claim 1 or 2, wherein, The protective layer (20) is attached to the central structure (10) in a pre-stressed manner at a working temperature of the support column (1) in the interval of 10 MPa to 30 MPa.

12. The support column of claim 1 or 2, wherein, The elongated body (5) comprises an opening extending along a longitudinal axis of the elongated body (5) and defining an inner surface of the central structure (10), wherein the protective layer (20) is arranged to the inner surface of the central structure (10).

13. The support column of claim 1 or 2, wherein, The rigid plate (22) of the protective layer (20) is wound onto the central structure (10) in a spiral form.

14. The support column of claim 1 or 2, wherein, The elongated body (5) comprises three elongated body segments (50), each body segment having two end sides and two long sides, wherein the body segments (50) are attached together at the long sides of the body segments (50) such that the body segments (50) together form a circumferential portion of the elongated body (5).

15. The support column of claim 14, wherein, The three elongated body segments (50) are arranged as respective truss assemblies, each comprising a hollow interior between an outer surface and an inner surface of the elongated body (5) and one or more support beams (62) extending between the outer surface and the inner surface.

16. The support column of claim 15, wherein, The truss assemblies are provided with a convex outer surface and alignment portions (64) configured to abut and connect to respective truss assemblies such that the truss assemblies collectively form a circumferential portion of the central structure (10).

17. The support column of claim 14, wherein, The three elongated body segments (50) are completely enclosed in the protective layer (20).

18. The support column of claim 14, wherein, The three body segments (50) have a tapered outer surface such that the three body segments (50) collectively form a tapered outer surface in the direction of the elongated extension of the support column (1).

19. The support column of claim 14, wherein, The body segments (50) comprise first attachment means (52) attaching the body segments (50) together along long sides of the body segments (50), wherein the first attachment means (52) comprise tongue and groove joints.

20. The support column of claim 19, wherein, The body segments (50) comprise second attachment means (54) attaching the body segments (50) together along short sides of the body segments (50), wherein the second attachment means (54) comprise tongue and groove joints.

21. The support column of claim 14, wherein, The body segments (50) comprise a first type segment (50a), a second type segment (50b) and a third type segment (50c), wherein the third type segment (50c) has a length of one third of the first type segment (50a) and the second type segment (50b) has a length of two thirds of the first type segment (50a), and wherein the elongated body (5) is assembled to connect end sides and long sides of the first type segment (50a), the second type segment (50b) and the third type segment (50c) such that a connection of end sides between two body segments (50) is located at a long side of two other body segments (50) forming the circumferential portion.

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