Triangular tension integral offshore wind power foundation structure

Abstract

The application provides a triangular tension integral offshore wind power foundation structure and relates to the field of offshore wind power foundation engineering.The device comprises a triangular floating platform, a triangular gravity foundation and a tension connection system; the tension connection system comprises a plurality of groups of cables, one end of the cable is connected to the triangular floating platform, the other end of the cable is connected to the triangular gravity foundation, and a static tension integral structure is formed between the triangular floating platform and the triangular gravity foundation. The triangular tension integral offshore wind power foundation structure is adopted, the platform displacement and the ballast demand are reduced, the complex mooring system and the piling operation are avoided, the production cost is reduced, the construction is simplified, the structural reliability and the dynamic performance are improved, and the device is suitable for the wind power development in the continental shelf sea area with a water depth of 50-200 meters.

Description

Technical Field

[0001] This invention relates to the field of offshore wind power foundation engineering, and in particular to a triangular tensioned integral offshore wind power foundation structure. Background Technology

[0002] Offshore wind energy reserves are abundant, and compared to onshore wind power, it has advantages such as higher wind speeds, more stable wind conditions, no occupation of land resources, and less noise and visual pollution. Offshore wind turbine foundations are mainly divided into two types: fixed and floating. Fixed foundations are mostly suitable for shallow sea areas with a water depth of less than 50 meters, and are fixed to the seabed using foundations such as monopiles or jackets. Floating foundations use a floating platform to support the superstructure of the wind turbine and are then anchored to the seabed by a mooring system; these include semi-submersible, SPAR, and tension leg foundations. Wind power development in nearshore waters with a water depth of less than 50 meters is mainly based on fixed foundations and is nearing saturation; moving towards deeper waters is an inevitable trend for offshore wind power development. Most continental shelf areas have water depths of less than 200 meters; therefore, finding new offshore wind turbine foundation structures suitable for water depths of 50 to 200 meters, with controllable costs, convenient installation and construction, and excellent dynamic performance has become a major demand for offshore wind power development.

[0003] The current technological bottleneck lies in the following: Semi-submersible and SPAR-type offshore wind turbine foundations use catenary anchor chains to fix them to the seabed. Their mooring systems primarily resist horizontal displacement caused by wind, waves, and currents. The restoring stiffness provided by the platform for vertical heave displacement and rotational displacement in the three directions is relatively small. Therefore, it is necessary to increase the size in the horizontal or vertical directions and utilize hydrostatic force or gravity to provide sufficient restoring stiffness. This results in the platform size and displacement being much larger than the overall structural empty weight, requiring the use of a large amount of ballast and significantly increasing costs. Tension leg offshore wind turbine foundations have a more compact platform design and maintain constant positive buoyancy. The tension legs in the mooring system are constantly under tension, and the tensile tension of the tension legs provides restoring stiffness for the platform. Therefore, tension leg platforms are less expensive than semi-submersible and SPAR-type platforms, but their tension leg mooring system is much more expensive than that of catenary mooring. Furthermore, there are technical challenges regarding fatigue damage of the tension legs and domestic alternatives. In addition, all of the above floating wind turbine foundations require a ground foundation to fix them to the seabed for mooring.

[0004] Therefore, there is an urgent need for a new type of structure that falls between fixed platforms and floating platforms to solve the economic problems of high wind power development costs and poor dynamic performance of wind power foundations in transitional deep water areas, so as to be suitable for transitional deep water areas with water depths of 50 to 200 meters and achieve cost reduction and efficiency improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a triangular tensioned integral offshore wind power foundation structure, which aims to solve the problems of high production cost, poor dynamic performance, and complex installation and construction of existing floating wind power foundations in water depths of 50 to 200 meters. It reduces platform displacement and ballast requirements, avoids complex mooring systems and piling operations, lowers production costs, simplifies construction, and improves structural reliability and dynamic performance, thus making it suitable for wind power development in continental shelf waters with depths of 50 to 200 meters.

[0006] To achieve the above objectives, the present invention provides a triangular tensioned integral offshore wind power foundation structure, comprising a triangular floating platform, a triangular gravity foundation, and a tensioning connection system; The tensioning connection system includes several sets of cables. One end of the cable is connected to the triangular floating platform, and the other end is connected to the triangular gravity foundation, so that the triangular floating platform and the triangular gravity foundation form a statically determinate tensioned integral structure.

[0007] Preferably, the triangular floating platform includes a triangular floating platform frame and three pontoons, which are respectively located at the three vertices of the triangular floating platform frame; a downwardly extending vertical support column is connected to one of the vertices of the triangular floating platform frame.

[0008] Preferably, the triangular gravity foundation includes a triangular gravity foundation outer frame and an upwardly extending vertical support column, which is connected to one of the vertices of the triangular gravity foundation outer frame.

[0009] Preferably, the centroids of the triangular floating platform and the triangular gravity foundation are aligned vertically, and the two are rotated 180 degrees relative to each other in the horizontal direction, so that their horizontal projections form a regular hexagon.

[0010] Preferably, the tensioning connection system includes seven sets of cables, one set of central cables and six sets of peripheral inclined cables; The central cable connects the lower end of the vertical downward support column to the upper end of the vertical upward support column; the six sets of peripheral inclined cables are paired up and correspond one-to-one with the three vertices of the triangular floating platform frame. Each set of peripheral inclined cables starts from the corresponding vertex and connects to the two endpoints of the side of the triangular gravity foundation frame closest to that vertex.

[0011] Preferably, the center of the outer frame of the triangular floating platform is provided with a tower base for installing the wind turbine tower, and the tower base is connected to three floating cylinders respectively through three crossbeams.

[0012] Therefore, the present invention adopts the above-mentioned triangular tensioned integral offshore wind power foundation structure, and the beneficial technical effects are as follows: (1) The triangular floating platform of the present invention is equipped with a pontoon, which can independently support the self-weight of the triangular floating platform, the wind turbine tower and the wind turbine under the action of buoyancy, so that the cables in the tension connection system are not stressed when there is no displacement between the triangular floating platform and the triangular gravity foundation, which greatly reduces the performance requirements of the mooring cables compared with the tension leg foundation.

[0013] (2) The triangular floating platform of the present invention can be towed to the installation area by tugboat during installation, thereby reducing the installation and construction costs.

[0014] (3) The triangular gravity foundation of the present invention is made of reinforced concrete and sits on the seabed as a gravity foundation of the whole system. Except for the settlement and bottoming, no additional piling or other foundation work is required. It has the advantages of low manufacturing cost, fast installation and construction time and low cost.

[0015] (4) The triangular floating platform of the present invention is connected to the triangular gravity foundation by seven sets of cables to form a complete tensioned integral structure. This structure is a statically determinate structure. When the triangular gravity foundation is fixed, the seven sets of cables can restrict the displacement of all six rigid body degrees of freedom of the triangular floating platform in three-dimensional space.

[0016] (5) The triangular floating platform and the triangular gravity foundation of the present invention rotate 180 degrees relative to each other in the horizontal direction. The triangle vertices of the triangular floating platform and the triangle vertices of the triangular gravity foundation are connected alternately and obliquely by six sets of external inclined cables. Compared with no relative rotation and vertical connection of the vertices, it can provide greater vertical axis rotation (yaw) torsional stiffness for the triangular floating platform.

[0017] (6) The seven sets of cables of the present invention are installed, connected and tightened after the upper and lower parts are in place. During this process, the relative position of the upper and lower parts of the structure can be adjusted by adjusting the length and tension of different sets of cables to compensate for the errors in the manufacturing and installation of the wind power system.

[0018] (7) The seven sets of cables of the present invention do not need to be subjected to long-term stress after installation and adjustment, which can greatly reduce the fatigue damage of the cables, thereby using low-cost materials to manufacture (such as ordinary steel chains), reducing costs and improving reliability. Attached Figure Description

[0019] Figure 1 This is an overall structural framework diagram of an embodiment of a triangular tensioned integral offshore wind power foundation structure according to the present invention; Figure 2 This is a top view of an embodiment of a triangular tensioned integral offshore wind power foundation structure according to the present invention; Figure 3 This is a side view of an embodiment of a triangular tensioned integral offshore wind power foundation structure according to the present invention; Figure 4 This is a front view of an embodiment of a triangular tensioned integral offshore wind power foundation structure according to the present invention.

[0020] Figure Labels 1. Triangular floating platform outer frame; 2. Floating pontoons; 3. Vertical downward support columns; 4. Tower base; 5. Crossbeams; 6. Triangular gravity foundation outer frame; 7. Vertical upward support columns; 8. Central cable; 9. Outer inclined cable. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0023] Example 1 like Figure 1 As shown, a triangular tensioned integral offshore wind power foundation structure includes a triangular floating platform, a triangular gravity foundation, and a tensioning connection system.

[0024] like Figure 2 , Figure 3 As shown, the triangular floating platform includes a triangular floating platform frame 1 and three pontoons 2. The three pontoons 2 are respectively located at the three vertices of the triangular floating platform frame 1, and provide buoyancy support for the triangular floating platform, wind turbine tower, and wind turbine. A downwardly extending vertical support column 3 is connected to one of the vertices of the triangular floating platform frame 1. A tower base 4 for installing the wind turbine tower is located at the center of the triangular floating platform frame 1. The tower base 4 is connected to the three pontoons 2 through three crossbeams 5, and the tower base 4 and the crossbeams 5 provide connection and support for the wind turbine tower and wind turbine.

[0025] like Figure 2 , Figure 3 As shown, the triangular gravity foundation includes a triangular gravity foundation outer frame 6 and an upwardly extending vertical support column 7, which is connected to one of the vertices of the triangular gravity foundation outer frame 6.

[0026] The triangular floating platform and the triangular gravity foundation are aligned vertically, and the two are rotated 180 degrees relative to each other in the horizontal direction, so that their horizontal projections are regular hexagons.

[0027] In this embodiment, the tensioning connection system includes seven sets of cables. One end of each cable is connected to a triangular floating platform, and the other end is connected to a triangular gravity foundation, thus forming a statically determinate tensioned monolithic structure between the triangular floating platform and the triangular gravity foundation. Figure 3 , Figure 4As shown. The buoyancy of the triangular floating platform can independently support the weight of the triangular floating platform itself, as well as the wind turbine tower and the wind turbine. This ensures that the cables are not stressed when there is no relative displacement between the upper and lower structures (i.e., the triangular floating platform and the triangular gravity foundation), which significantly reduces the performance requirements of the mooring cables compared to tension leg foundations.

[0028] The tensioning connection system includes seven sets of cables, one set of central cables 8 and six sets of peripheral inclined cables 9. The central cable 8 connects the lower end of the vertical downward support column 3 to the upper end of the vertical upward support column 7. The six sets of peripheral inclined cables 9 are paired up and correspond one-to-one with the three vertices of the triangular floating platform outer frame 1. Each set of peripheral inclined cables 9 starts from the corresponding vertex and connects to the two endpoints of the side of the triangular gravity foundation outer frame 6 closest to that vertex.

[0029] During installation, the triangular floating platform can self-float using the buoyancy of its three pontoons 2 and be towed to the installation area by tugboat. The triangular gravity foundation is made of reinforced concrete and sits on the seabed as a gravity foundation, requiring no additional piling or other foundation work except for settling. After the upper and lower structures are in place, seven sets of cables are installed, connected, and tightened. The relative position of the upper and lower structures is adjusted by changing the length and tension of different sets of cables to compensate for manufacturing and installation errors.

[0030] Once installed and adjusted, the seven sets of cables do not require prolonged stress, significantly reducing fatigue damage and allowing for the use of low-cost materials (such as ordinary steel chains) in manufacturing, thus lowering costs and improving reliability. When the triangular gravity foundation is fixed, the seven sets of cables can restrict the displacement of the triangular floating platform in all six rigid body degrees of freedom in three-dimensional space. The specific restriction process is as follows: downward displacement of the triangular floating platform causes tension on the central cable 8, thus restricting it; upward displacement of the triangular floating platform causes tension on the outer inclined cables 9, thus restricting it; horizontal displacement of the triangular floating platform causes tension on all seven sets of cables, thus restricting it; rotational displacement of the triangular floating platform about two horizontal axes (i.e., roll and pitch) causes tension on the outer inclined cables 9 on the side away from the gravity foundation, thus restricting it; rotational displacement of the triangular floating platform about the central vertical axis (i.e., yaw) causes tension on one of the outer inclined cables 9 in one of the tilting directions, and simultaneously causes tension on the central cable 8, thus restricting it.

[0031] Therefore, the present invention adopts the above-mentioned triangular tensioned integral offshore wind power foundation structure, which solves the problems of high production cost, poor dynamic performance, and complex installation and construction of existing floating wind power foundations in water depth transition areas of 50 meters to 200 meters. It reduces platform displacement and ballast requirements, avoids complex mooring systems and piling operations, lowers production costs, simplifies construction, and improves structural reliability and dynamic performance. It is suitable for wind power development in continental shelf waters with depths of 50 meters to 200 meters.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A triangular tensioned monolithic offshore wind power foundation structure, characterized in that, Includes a triangular floating platform, a triangular gravity foundation, and a tensioning connection system; The tensioning connection system includes several sets of cables, one end of which is connected to the triangular floating platform and the other end of which is connected to the triangular gravity foundation, so that the triangular floating platform and the triangular gravity foundation form a statically determinate tensioned integral structure.

2. The triangular tensioned integral offshore wind power foundation structure according to claim 1, characterized in that, The triangular floating platform includes a triangular floating platform frame and three pontoons, which are respectively located at the three vertices of the triangular floating platform frame; a downwardly extending vertical support column is connected to one of the vertices of the triangular floating platform frame.

3. The triangular tensioned integral offshore wind power foundation structure according to claim 2, characterized in that, The triangular gravity foundation includes a triangular gravity foundation outer frame and an upwardly extending vertical support column, which is connected to one of the vertices of the triangular gravity foundation outer frame.

4. The triangular tensioned integral offshore wind power foundation structure according to claim 1, characterized in that, The triangular floating platform and the triangular centroid of the triangular gravity foundation are aligned vertically, and the two are rotated 180 degrees relative to each other in the horizontal direction, so that their horizontal projections form a regular hexagon.

5. The triangular tensioned integral offshore wind power foundation structure according to claim 3, characterized in that, The tension connection system includes seven sets of cables, one set of central cables and six sets of peripheral inclined cables; The central cable connects the lower end of the vertical downward support column to the upper end of the vertical upward support column; the six sets of peripheral inclined cables are paired up and correspond one-to-one with the three vertices of the triangular floating platform frame. Each set of peripheral inclined cables starts from the corresponding vertex and connects to the two endpoints on the side of the triangular gravity foundation frame closest to that vertex.

6. The triangular tensioned integral offshore wind power foundation structure according to claim 2, characterized in that, The outer frame of the triangular floating platform is provided with a tower base for installing the wind turbine tower at its center. The tower base is connected to three floating cylinders by three crossbeams.

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