Foot-expanding assembled lattice type tower suitable for large-scale wind turbine generator

Abstract

The invention discloses a structural tower suitable for a large wind turbine generator, which comprises a steel tower drum, a switching node and a lattice tower, the lattice tower comprises a foot expanding section, a straight section and a variable angle section for connecting the foot expanding section and the straight section, the straight section is positioned above a blade tip, and the foot expanding section is positioned below the blade tip; a prestressed cable bundle channel is formed in the variable-angle section in the axial direction of the variable-angle section, a smooth inward-convex structure facing the steering side is formed in the position, where the prestressed cable bundle steers, of the prestressed cable bundle channel, and the cross section, at the smooth inward-convex structure, of the prestressed cable bundle channel is a bell-shaped hole with one large end and the other small end; the small end of the bell-shaped hole is an arc section with the diameter larger than that of the prestressed cable bundle, the small end of the bell-shaped hole faces the steering direction of the prestressed cable bundle, and the shape of the bell-shaped hole is gradually reduced from the two ends of the smooth inward-protruding structure to the center hole, so that the smooth inward-protruding structure is formed. According to the application, the prestressed cable bundle can be controlled and uniformly steered, and the prestress loss is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, in particular to an expanded-leg combined lattice tower suitable for large wind turbines. Background Art

[0002] With the rapid development of wind power as a representative of clean energy, in recent years, there has been a clear trend towards larger wind turbines in order to continuously improve wind resource utilization and return on investment. This is reflected in the continuous increase in unit capacity and blade length. These factors have placed more stringent requirements on wind turbine towers and have become a bottleneck restricting the development of larger wind turbines. On the one hand, wind turbine towers need to have higher load-bearing capacity to cope with more stringent load environments, and on the other hand, wind turbine towers need to reach higher heights to lift the ever-growing number of wind turbine blades.

[0003] Traditional wind turbine towers are poorly suited for large wind turbines. For example, single-tube steel towers are prone to wall resonance, excessive steel plate thickness, and machining difficulties, making them generally suitable for construction heights around 120 meters. Single-tube hybrid towers are prone to the excessive volume of precast concrete components, making prefabrication and construction quality difficult to guarantee, and transportation challenges, making them generally suitable for heights around 180 meters. Against this backdrop, lattice wind turbine towers, with their high component load-bearing efficiency, ease of transportation and hoisting, and convenient and reliable connection, have become a more promising choice for large wind turbine support structures.

[0004] An existing Chinese invention patent application with application number 202411591277.6 discloses a lattice wind turbine tower comprising a top tower section, a transition section, and a lattice section. The top of the transition section is fixed to the top tower section, and the top of the lattice section is fixed to the transition section. The lattice section includes several corner posts and several reinforcements. All corner posts enclose a corner post frame, and the tops of all corner posts are fixed to the transition section. The reinforcements are connected to two adjacent corner posts along the sides of the corner post frame. Each corner post is provided with a corner post inflection point, at which the corner post bends outward from the corner post frame. The height of the corner post inflection point is configured to be lower than or equal to the lowest height of the blade tip to ensure that the blade does not collide with the tower during operation. This allows the taper of the lattice section below the corner post inflection point to be flexibly adjusted, resulting in higher structural efficiency and reduced material consumption. Adjusting the lattice section taper can also flexibly adjust the tower frequency, thereby avoiding the wind turbine's resonance range and ensuring tower safety.

[0005] The above-mentioned solution of expanding the feet of the lattice tower below the blade range is more suitable for the case where the blades are longer, but it will also lead to problems such as tower column variable angle and prestressed cable bundle steering. It is necessary to adopt special tower column forms and targeted structural measures, which makes the manufacturing process of the tower column in the variable angle section complicated and difficult to process, and also causes non-standard tower column specifications, which brings obstacles to large-scale production. In addition, the existing technology also has the problem of serious prestress loss at the variable angle when the prestressed cable bundle is tensioned. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a lattice tower with expanded legs suitable for large wind turbines.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention discloses an expanded foot combined lattice tower suitable for large wind turbines, comprising a steel tower, a conversion node, and a lattice tower. The lattice tower comprises an expanded foot section, a straight section, and a variable angle section connecting the expanded foot section and the straight section. The straight section is located above the blade tip, and the expanded foot section is located below the blade tip. The variable angle section is provided with a prestressed cable bundle channel along its axial direction, and the prestressed cable bundle channel forms a smooth inward convex structure facing the turning side at the position where the prestressed cable bundle turns, and the cross-section of the prestressed cable bundle channel at the smooth inward convex structure is a bell-shaped hole with one end larger than the other end, and the small end of the bell-shaped hole is a circular arc segment with a diameter larger than the diameter of the prestressed cable bundle, and the small end of the bell-shaped hole faces the direction of the prestressed cable bundle turning, and the shape of the bell-shaped hole gradually decreases from the two ends of the smooth inward convex structure to the central hole, thereby forming a smooth inward convex structure.

[0008] The present invention provides an expanded-leg combined lattice tower suitable for large wind turbines. Furthermore, the variable angle section includes an external steel pipe, an upper inner steel pipe and a lower inner steel pipe arranged at both ends of the external steel pipe, and an inner lining steel plate arranged in the center of the external steel pipe. The upper inner steel pipe, the lower inner steel pipe and the inner lining steel plate enclose a prestressed cable bundle channel, a smooth inward convex structure is formed at the inner lining steel plate, and a filler is provided between the external steel pipe and the prestressed cable bundle channel.

[0009] The present invention provides an expanded foot combined lattice tower suitable for large wind turbines. Furthermore, an inner ring plate is provided between the inner lining steel plate and the outer steel pipe, and the inner ring plate is provided with a bell-shaped hole adapted to the cross section of the inner lining steel plate.

[0010] The present invention provides an expanded-leg combined lattice tower suitable for large wind turbines. Furthermore, three inner ring plates are arranged at axial intervals along the inner lining steel plate, namely an upper inner ring plate, a middle inner ring plate and a lower inner ring plate. The bell-shaped hole on the middle inner ring plate is smaller than the bell-shaped holes on the upper inner ring plate and the lower inner ring plate.

[0011] The present invention provides an expanded-leg combined lattice tower suitable for large wind turbines. Furthermore, a web connecting portion is provided on the external steel pipe, and longitudinal stiffening ribs are provided at corresponding positions of the web connecting portion. The longitudinal stiffening ribs are located between the external steel pipe and the upper inner steel pipe, and between the external steel pipe and the lower inner steel pipe.

[0012] The present invention provides an expanded-leg combined lattice tower suitable for large wind turbines. Further, the lattice tower comprises four prestressed steel tube concrete tower columns and a plurality of diagonal webs and transverse webs distributed between the prestressed steel tube concrete tower columns.

[0013] The present invention provides an expanded-leg combined lattice tower suitable for large wind turbines. Furthermore, the upper part of the conversion node is connected to the steel tower barrel, and the lower part is connected to the lattice tower. The conversion node includes four lower connecting parts connected to the prestressed steel tube concrete tower column and an upper connecting part connected to the steel tower barrel. The upper end of the lower connecting part is provided with a prestressed cable anchor for anchoring the upper end of the prestressed cable bundle.

[0014] The present invention provides an expanded-leg combined lattice tower suitable for large wind turbines. Furthermore, the prestressed cable anchor comprises an upper cover plate, a lower cover plate, and annular ribs and radial ribs connected between the upper cover plate and the lower cover plate, and cable through holes are provided on the upper cover plate and the lower cover plate.

[0015] The present invention provides an expanded-leg combined lattice tower suitable for large wind turbines. Furthermore, a distributed foundation is provided under the lattice tower. The distributed foundation is respectively located under the tower columns of the lattice tower, and includes piles and a base. An operating cavity is provided in the base, and a cable through hole and a manhole connected to the operating cavity are reserved on the base; the lower end of the prestressed cable bundle is anchored in the operating cavity by a prestressed cable anchor.

[0016] The present invention provides an expanded foot combined lattice tower suitable for large wind turbines. Furthermore, the top of the base is provided with a through hole connected to the operating cavity, a balancing steel cylinder is provided at the through hole, and the lower end of the balancing steel cylinder is connected to a prestressed cable anchor.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. This application adds a corner section, which is a separate component from the tower column. This section can simultaneously achieve tower column angle change and prestressed cable bundle steering. This facilitates processing and ensures the uniformity of tower column component form and structure, facilitating large-scale production. When the prestressed cable bundle is tensioned, it can automatically gather and smoothly steer, reducing prestress loss caused by steering. 2. The bell-shaped hole ensures maximum cable space while allowing the prestressed cables to automatically converge toward the center after tensioning and essentially maintain their pre-deviating cross-sectional shape. This reduces prestress loss caused by deflection and prevents additional prestress loss caused by the prestressed cables contacting the hole wall after deflection. 3. The lattice tower of this application meets the load-bearing capacity and fatigue resistance requirements of the support structure of large-capacity wind turbines, breaks through the blade length limit, is easy to produce and transport, and is convenient and reliable to install; 4. The bell-shaped cross-section formed in this application can control the cross-sectional shape of the prestressed cable bundle, which is particularly important when the size difference between the channel and the cable bundle is large. In comparison, the traditional bend pipe directly turns, the cable bundle will be flattened, and the cross-sectional shape cannot be maintained well. Under wind load, the tower body vibrates back and forth, and continuous slippage and wear may occur between individual cables.

[0018] The present invention will be further described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 This is a schematic structural diagram of a prestressed steel tube concrete tower column according to the present invention; Figure 3 This is a schematic plan view of the connection between the tower column and the web member of the present invention; Figure 4 This is a schematic diagram of a conversion node of the present invention; Figure 5 This is a schematic plan view of the prestressed cable anchor of the present invention; Figure 6 This is a schematic elevation view of a prestressed cable anchor according to the present invention; Figure 7 A schematic diagram of the structure based on the present invention; Figure 8 This is a schematic diagram of the installation structure of the variable angle section of the present invention; Figure 9 Schematic diagram of the variable angle section structure of the present invention; Figure 10 This is a schematic plan view of the connection between the angle-changing section and the web member of the present invention; Figure 11 This is a schematic elevation view of the connection between the angle-changing section and the web member of the present invention; Figure 12 This is a schematic plan view of the angle-changing section at the inner ring plate of the present invention; Figure 13 This is a schematic plan view of the inner ring plate of the present invention; Figure 14 This is a schematic diagram of the installation of the low-friction plate of the present invention.

[0020] Reference numerals: 1. Steel tower; 2. Transition node; 2.1. Lower connection; 2.2. Upper connection; 2.3. Prestressed cable anchor; 2.31. Upper cover; 2.32. Lower cover; 2.33. Ring ribs; 2.34. Radial ribs; 3. Lattice tower; 3.1. Straight section; 3.2. Expanded foot section; 3.3. Variable angle section; 3.31. Upper tower column connection; 3.32. Lower tower column connection; 3.33. Web member connection; 3.34. External steel pipe; 3.35. Upper inner steel pipe; 3.36. Lower inner steel pipe; 3.37. Lining steel plate; 3. 4. Prestressed concrete-filled steel tube tower column; 3.41. Outer steel tube; 3.42. Inner steel tube; 3.43. Concrete; 3.5. Diagonal web members; 3.6. Transverse web members; 3.7. Longitudinal stiffeners; 3.8. Upper inner ring plate; 3.81. Middle hole; 3.82. Side hole; 3.9. Middle inner ring plate; 3.10. Lower inner ring plate; 3.11. Low-friction plate; 4. Foundation; 4.1. Piles; 4.2. Capping platform; 4.3. Operating cavity; 4.4. Cable hole; 4.5. Manhole; 4.6. Balancing steel cylinder; 5. Wind turbine; 6. Prestressed cable. DETAILED DESCRIPTION

[0021] like Figure 1-14 As shown, the present invention discloses an expanded-leg combined lattice tower suitable for large wind turbines, comprising a steel tower 1, a conversion node 2, a lattice tower 3 and a distributed foundation 4. The upper end of the steel tower 1 is connected to the wind turbine 5, and the lower end is connected to the conversion node 2; the upper end of the conversion node 2 is connected to the steel tower 1, and the lower end is connected to the lattice tower 3; the lower part of the lattice tower 3 is connected to the distributed foundation 4.

[0022] The lattice tower 3 is an expanded foot prestressed steel tube concrete frame, which includes a straight section 3.1, an expanded foot section 3.2 and a variable angle section 3.3. The straight section 3.1 is located above the blade tip, the outer contour of the tower cross section is small, and the tower columns are arranged vertically to avoid tower sweeping; the expanded foot section 3.2 is located below the blade tip, and the tower columns are angled near the blade tip through the assembly part variable angle section 3.3. The outer contour of the tower cross section gradually expands downward to improve the stiffness and bearing capacity of the tower.

[0023] The lattice tower 3 includes four prestressed steel tube concrete tower columns 3.4 and a number of diagonal webs 3.5 and transverse webs 3.6 distributed between the prestressed steel tube concrete tower columns 3.4. The diagonal webs 3.5 and transverse webs 3.6 are all steel tubes and are connected to the prestressed steel tube concrete tower columns 3.4 through bolt nodes.

[0024] The prestressed steel tube concrete tower column 3.4 comprises an outer steel tube 3.41, an inner steel tube 3.42, and concrete 3.43 filling the space between the two tubes. The inner steel tube 3.42 has through-holes for tensioning the prestressed cables 6. The concrete 3.43 is prefabricated in the factory, and prestressing is applied on-site using the post-tensioning method. Anchorages are located at the distributed foundations 4 and at the transition nodes 2. By filling the tower column's steel tube with concrete 3.43, the two elements work together to significantly improve the column's bearing capacity and fatigue resistance. Prestressing the tower column prevents tensile cracking in the concrete 3.43 during operation. For ease of transportation, the tower column is divided into several sections, connected by flanges. The concrete 3.43 sections at these connections are bonded on-site using adhesive. A thickened inner steel tube 3.42 is installed at the connection with the web members, and longitudinal stiffeners 3.7 are positioned at the corresponding locations on the web member connection plates to strengthen the joint area and ensure overall load-bearing.

[0025] The angle-changing section 3.3 consists of a steering portion, an upper tower column connection 3.31, a lower tower column connection 3.32, and a web connection 3.33. The upper tower column connection 3.31 is flanged, connecting to the upper tower column at the same angle as the upper tower column flange. The lower tower column connection 3.32 is also flanged, connecting to the lower tower column at the same angle as the lower tower column flange. The web connection 3.33 is a steel plate, located where the webs are to be connected. Its shape coordinates with the web distribution and contains pre-set bolt holes.

[0026] The steering portion includes an outer steel tube 3.34, an upper inner steel tube 3.35 and a lower inner steel tube 3.36 located at both ends of the outer steel tube 3.34, and an inner lining steel plate 3.37 located in the center of the outer steel tube 3.34. The upper inner steel tube 3.35, the lower inner steel tube 3.36, and the inner lining steel plate 3.37 enclose a prestressed cable bundle passage. The inner lining steel plate 3.37 is supported and shaped by an upper inner ring plate 3.8, a middle inner ring plate 3.9, and a lower inner ring plate 3.10. A smooth inward convex structure is formed at the desired position at the prestressed cable bundle steering position, thereby achieving controllable and uniform steering of the prestressed cable bundle.

[0027] Longitudinal stiffening ribs 3.7 are provided at corresponding positions of the web connecting portion 3.33. The longitudinal stiffening ribs 3.7 are located between the outer steel pipe 3.34 and the upper inner steel pipe 3.35, and between the outer steel pipe 3.34 and the lower inner steel pipe 3.36.

[0028] The inner side of the inner lining steel plate 3.37 is covered with a low-friction plate 3.11 to facilitate the tensioning of the prestressed cable strands and reduce prestress loss. The inner lining steel plate 3.37 on the outer side of the corner generally does not contact the prestressed cable strands, so the low-friction plate 3.11 may not be provided. Concrete 3.43 or high-strength grouting material is filled between the external steel pipe 3.34 and the prestressed cable strand channel to ensure the rigidity and strength of the steering portion.

[0029] The upper inner ring plate 3.8, the middle inner ring plate 3.9 and the lower inner ring plate 3.10 are similar in shape. Taking the upper inner ring plate 3.8 as an example, a middle hole 3.81 and side holes 3.82 are formed therein. The middle hole 3.81 is an eccentric bell-shaped hole with one end larger than the other. The large end is an arc segment with the same outer diameter as the upper inner steel tube 3.35, and the small end is an arc segment with a diameter slightly larger than the prestressed cable bundle. The concave portion of the arc segment faces the turning side, and the center of the circle is located at the center of the upper inner ring plate 3.8. This special shape of the opening allows the prestressed cable bundle to automatically converge toward the center after tensioning and basically maintain its cross-sectional shape before turning, while ensuring as much space as possible for cable threading. On the one hand, this can reduce the prestress loss caused by turning, and on the other hand, it can prevent the prestressed cable bundle 6 from contacting the hole wall after changing direction, causing additional prestress loss.

[0030] The middle hole 3.81 of the middle inner ring plate 3.9 is smaller than the middle holes 3.81 of the upper inner ring plate 3.8 and the lower inner ring plate 3.10 to complete the deflection of the 6 bundles of prestressed cables, forming a smooth inwardly convex through-hole structure with larger ends and a smaller center.

[0031] The turning node 2 is made of steel and comprises four lower connection parts 2.1 connected to the prestressed steel tube concrete tower column 3.4 and an upper connection part 2.2 connected to the steel tower tube 1, all of which are connected by flanges.

[0032] A beam-type prestressed cable anchor 2.3 is provided at the upper end of the lower connecting portion 2.1 for anchoring the upper end of the prestressed cable 6. The beam-type prestressed cable anchor 2.3 comprises an upper cover plate 2.31, a lower cover plate 2.32, and an annular rib 2.33 and radial ribs 2.34 connected between the upper cover plate 2.31 and the lower cover plate 2.32. Cable through holes are provided on the upper cover plate 2.31 and the lower cover plate 2.32 at positions corresponding to the prestressed cable bundles, thereby adapting to the high level of prestressing required for large wind turbines 5 and high towers and the requirements for anchoring, and solving the problem of large deformation of traditional plate-type prestressed anchors under the action of high level of prestressing.

[0033] The distributed foundation 4 is in the form of a pile cap, and there are four of them, located under the four tower columns. Each foundation 4 includes a pile 4.1 and a cap 4.2. In order to meet the prestressing operation requirements, a prestressed operation cavity 4.3 is set in the middle of the cap 4.2, and a cable hole 4.4 and a manhole 4.5 are reserved. A through hole connected to the operation cavity 4.3 is provided at the top of the cap 4.2. In order to avoid local compressive damage at the top of the cap 4.2 due to high-level prestress, a balancing steel cylinder 4.6 is provided at the through hole. The lower end of the balancing steel cylinder 4.6 is connected to the prestressed cable anchor 2.3 for anchoring the lower end of the prestressed cable 6.

[0034] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A lattice tower with expanded legs suitable for large wind turbines, comprising a steel tower, a conversion node and a lattice tower, characterized in that: The lattice tower comprises an expanded foot section, a straight section, and a variable angle section connecting the expanded foot section and the straight section, wherein the straight section is located above the blade tip, and the expanded foot section is located below the blade tip; The variable angle section is provided with a prestressed cable bundle channel along its axial direction, and the prestressed cable bundle channel forms a smooth inward convex structure facing the turning side at the position where the prestressed cable bundle turns, and the cross-section of the prestressed cable bundle channel at the smooth inward convex structure is a bell-shaped hole with one end larger than the other end, and the small end of the bell-shaped hole is a circular arc segment with a diameter larger than the diameter of the prestressed cable bundle, and the small end of the bell-shaped hole faces the direction of the prestressed cable bundle turning, and the shape of the bell-shaped hole gradually decreases from the two ends of the smooth inward convex structure to the central hole, thereby forming a smooth inward convex structure.

2. The expanded foot combined lattice tower suitable for large wind turbines according to claim 1, characterized in that: The variable angle section includes an external steel pipe, an upper inner steel pipe and a lower inner steel pipe arranged at both ends of the external steel pipe, and an inner lining steel plate arranged in the center of the external steel pipe. The upper inner steel pipe, the lower inner steel pipe and the inner lining steel plate enclose a prestressed cable bundle channel. A smooth inward convex structure is formed at the inner lining steel plate. Filling material is provided between the external steel pipe and the prestressed cable bundle channel.

3. The expanded foot combined lattice tower suitable for large wind turbines according to claim 2, characterized in that: An inner ring plate is provided between the inner lining steel plate and the outer steel pipe, and a bell-shaped hole adapted to the cross section of the inner lining steel plate is provided on the inner ring plate.

4. The expanded foot combined lattice tower suitable for large wind turbines according to claim 3, characterized in that: The inner ring plate is arranged in three rows along the axial direction of the inner lining steel plate, namely an upper inner ring plate, a middle inner ring plate and a lower inner ring plate. The bell-shaped hole on the middle inner ring plate is smaller than the bell-shaped holes on the upper inner ring plate and the lower inner ring plate.

5. The expanded foot combined lattice tower suitable for large wind turbines according to claim 2, characterized in that: The outer steel pipe is provided with a web connecting portion, and a longitudinal stiffening rib is provided at a corresponding position of the web connecting portion. The longitudinal stiffening rib is located between the outer steel pipe and the upper inner steel pipe, and between the outer steel pipe and the lower inner steel pipe.

6. The expanded foot combined lattice tower suitable for large wind turbines according to claim 1, characterized in that: The lattice tower comprises four prestressed steel tube concrete tower columns and a plurality of diagonal web members and transverse web members distributed between the prestressed steel tube concrete tower columns.

7. The expanded foot combined lattice tower suitable for large wind turbines according to claim 6, characterized in that: The upper part of the conversion node is connected to the steel tower, and the lower part is connected to the lattice tower. The conversion node includes four lower connecting parts connected to the prestressed steel tube concrete tower column and an upper connecting part connected to the steel tower. The upper end of the lower connecting part is provided with a prestressed cable anchor for anchoring the upper end of the prestressed cable bundle.

8. The expanded foot combined lattice tower suitable for large wind turbines according to claim 7, characterized in that: The prestressed cable anchor comprises an upper cover plate, a lower cover plate, and annular ribs and radial ribs connected between the upper cover plate and the lower cover plate. Cable through holes are provided on the upper cover plate and the lower cover plate.

9. The expanded foot combined lattice tower suitable for large wind turbines according to claim 1, characterized in that: A distributed foundation is provided under the lattice tower, and the distributed foundation is respectively located under the tower columns of the lattice tower, and includes piles and a pedestal. An operating cavity is provided in the pedestal, and a cable through hole and a manhole connected to the operating cavity are reserved on the pedestal; the lower end of the prestressed cable bundle is anchored in the operating cavity by a prestressed cable anchor.

10. The expanded foot combined lattice tower suitable for large wind turbines according to claim 9, characterized in that: A through hole communicating with the operating cavity is provided on the top of the pedestal, a balancing steel cylinder is provided at the through hole, and the lower end of the balancing steel cylinder is connected to a prestressed cable anchor.

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