A combined tension leg floating wind turbine and method of installation thereof

Abstract

The application belongs to the technical field of offshore wind power generation, and relates to a combined tension leg floating type wind turbine and a mounting method thereof. The combined tension leg floating type wind turbine comprises a main floating body, a plurality of water surface floating buoys, a plurality of first tensioning tendons, a plurality of second tensioning tendons and a plurality of gravity type foundations. The upper end of the main floating body is provided with a wind turbine. The plurality of water surface floating buoys are arranged around the outer periphery of the main floating body. One end of the first tensioning tendon is connected with one water surface floating buoy, and the other end is connected with the main floating body. One end of the second tensioning tendon is connected with the main floating body, and the other end is connected with one gravity type foundation. The application realizes the modularized split mounting mode to greatly reduce the construction threshold and construction cost in the deep sea complex environment, and simultaneously utilizes the distributed floating buoys and double tensioning mooring to improve the anti-overturning and heave suppression performance.

Description

Technical Field

[0001] This invention belongs to the field of offshore wind power generation technology, and relates to a combined tension leg floating wind turbine and its installation method. Background Technology

[0002] Offshore wind power, especially deep-sea wind power, has become an important direction for future energy development due to its abundant wind resources, stable wind speeds, and relatively small impact on the terrestrial environment. When the water depth exceeds 60 meters, the economic and technical feasibility of traditional fixed foundations (such as monopiles and jackets) decreases sharply, making floating platforms the preferred solution for mounting wind turbine generators. Currently, the mainstream floating wind turbine foundation types include barge-type, semi-submersible, and tension leg platforms (TLP). Among them, TLP-type floating wind turbines are connected to the seabed foundation through tensioned vertical mooring cables, which almost completely restricts the platform's heave, pitch, and roll movements, exhibiting excellent motion performance and stability, which is highly beneficial for the operation of wind turbine generators.

[0003] Traditional TLP (Tension Levitation Platform) floating wind turbine designs typically consist of a central column and three or four buoyancy arms extending radially from it, forming an integral buoyancy structure. The entire structure is directly connected to suction piles or gravity foundations on the seabed via multiple tension legs (steel cables or pipes), with the turbine tower mounted atop the central column. The platform's stability relies primarily on the enormous pretension provided by the mooring system to resist overturning moments caused by environmental loads such as wind, waves, and currents. However, this traditional integral TLP platform has significant shortcomings in practical applications. First, its installation is difficult and costly: integral TLP platforms are bulky, placing extremely high demands on port facilities and installation vessels (such as large crane vessels). Furthermore, the connection and tensioning of the tension legs at sea is complex, sensitive to sea conditions, and carries high technical risks, resulting in high overall installation costs. Second, the mooring system design is complex: the tension legs must withstand enormous pretension and dynamic loads, placing extremely stringent requirements on material strength, fatigue performance, and the design of connectors, increasing manufacturing costs and maintenance difficulty. Secondly, traditional TLPs are quite sensitive to changes in water depth, and the length of the mooring cables needs to be prefabricated according to the precise water depth, resulting in poor adaptability. Finally, it is difficult to balance stability and economy: to obtain sufficient restoring torque to ensure platform stability, a large horizontal dimension is required, which increases the weight, volume, and construction cost of the structure. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides a combined tension leg floating wind turbine and its installation method, which significantly reduces the construction threshold and cost by using a modular, split installation method in complex deep-sea environments. At the same time, it improves the anti-capsulation and heave suppression performance by utilizing distributed buoys and dual tension mooring in synergy.

[0005] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a combined tension leg floating fan, comprising: A main float, wherein a fan is provided at the upper end of the main float; Multiple surface buoys are arranged around the outer periphery of the main buoy body; Multiple first tension ribs, one end of which is connected to one of the water surface floats, and the other end of which is connected to the main float; Multiple secondary tension ribs; Multiple gravity foundations are provided, all of which are set on the seabed; one end of the second tension rib is connected to the main buoy, and the other end is connected to one of the gravity foundations.

[0006] Preferably, the number of surface buoys is three, and the three surface buoys are evenly arranged around the circumference of the main buoy.

[0007] Preferably, the main buoy includes: A vertically positioned central column; A horizontal pontoon is fixedly connected to the lower end of the central column; One end of the first tension rib is connected to the surface buoy, and the other end is connected to the end of the horizontal buoy; one end of the second tension rib is connected to the end of the horizontal buoy, and the other end is connected to the gravity foundation.

[0008] Preferably, the horizontal pontoon comprises: The main transverse pontoon is fixedly connected to the lower end of the central column at its middle section. A longitudinal buoy, one end of which is fixedly connected to the middle of the main transverse buoy, and the longitudinal buoy is arranged perpendicular to the main transverse buoy.

[0009] Preferably, triangular reinforcing plates are provided at the connection between the main transverse pontoon and the longitudinal pontoon, as well as at the connection between the main transverse pontoon and the central column.

[0010] Preferably, the end of the horizontal pontoon is provided with a first connecting lug and a second connecting lug, the first connecting lug being hinged to the end of the first tension rib, and the second connecting lug being hinged to the end of the second tension rib.

[0011] Preferably, the surface pontoon includes a cylindrical body and a lifting lug disposed at the bottom of the cylindrical body, the lifting lug being hinged to the end of the first tension rib.

[0012] Preferably, the surface pontoon is internally provided with multiple horizontal baffles, which divide the surface pontoon into multiple independent ballast compartments arranged in a vertical direction; each independent ballast compartment is provided with a ballast water pipeline interface and a vent valve interface that communicate with the outside.

[0013] Preferably, the gravity foundation includes a concrete base and a connecting anchor ring pre-embedded in the concrete base, and the end of the second tension bar is connected to the connecting anchor ring.

[0014] Secondly, the present invention provides an installation method for a combined tension leg floating fan, comprising the following steps: The gravity foundations are respectively installed at the first predetermined positions on the seabed; The main buoy and the wind turbine installed on its upper end were transported as a whole to the installation area. Connect one end of each of the second tension ribs to the main float, connect the other end of each of the second tension ribs to the corresponding gravity foundation, and apply pretension to each of the second tension ribs; Transport the multiple surface pontoons to the second preset position corresponding to the outer periphery of the main buoy; One end of each of the first tension ribs is connected to the corresponding surface float, the other end of each of the first tension ribs is connected to the main float, and pretension is applied to each of the first tension ribs.

[0015] Compared with the prior art, the present invention has the following beneficial effects: On the one hand, the arrangement of multiple surface pontoons creates asymmetric buoyancy changes when the platform tilts, contributing additional restoring torque and significantly improving the overall anti-overturning stability. On the other hand, the dual tension mooring design, with the main float connected to the surface pontoons via a first tension rib and the main float connected to the gravity foundation via a second tension rib, allows the main float to simultaneously bear tension constraints from below and the sides, effectively limiting the platform's heave, pitch, and roll movements, providing a stable platform for wind turbine operation with near-fixed foundation stability. Furthermore, the main float, surface pontoons, and gravity foundation are all relatively independent modules that can be manufactured and transported separately. On-site assembly can be completed simply by connecting them via tension ribs, significantly reducing the reliance of traditional integral tension leg platforms on large installation vessels and deep-water ports. This achieves lower construction and installation costs and wider adaptability to different sea areas while ensuring superior motion performance. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a combined tension leg floating fan according to the present invention.

[0018] The components include: 1. Main buoy; 2. Surface buoy; 3. First tension rib; 4. Second tension rib; 5. Gravity foundation. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply refers to its direction relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0024] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0025] The present invention will now be described in further detail with reference to the accompanying drawings: The first objective of this invention is to provide a combined tension leg floating fan, such as... Figure 1 As shown, it includes: Main float 1, with a fan installed at its upper end; Multiple surface buoys 2 are arranged around the outer periphery of the main buoy 1; Multiple first tension ribs 3, one end of the first tension rib 3 is connected to one of the water surface floats 2, and the other end is connected to the main float 1; Multiple second tension ribs 4; Multiple gravity foundations 5 are provided on the seabed; one end of the second tension rib 4 is connected to the main buoy 1, and the other end is connected to one of the gravity foundations 5.

[0026] like Figure 1 As shown, the floating wind turbine includes: a main float 1, the upper end of which is used to install the wind turbine generator set (including tower, nacelle, and blades); multiple surface floats 2, which are evenly arranged around the outer perimeter of the main float 1 to form a distributed buoyancy system; multiple first tension ribs 3, one end of each first tension rib 3 is fixedly connected to a surface float 2, and the other end is connected to the lower part of the main float 1, and is in a tensioned state after installation, thereby reliably positioning the surface float 2 around the main float 1; multiple second tension ribs 4; and multiple gravity foundations 5, which are pre-placed at predetermined positions on the seabed. One end of each second tension rib 4 is connected to the main float 1, and the other end is connected to a corresponding gravity foundation 5, providing downward pretension to the main float 1 after tensioning.

[0027] During operation, the buoyancy of the main float 1 is balanced by the pretension of the second tension rib 4, effectively limiting the heave, pitch, and roll motions of the entire floating wind turbine. Simultaneously, when the wind turbine tilts under external load, the submerged volume of each surface float 2 changes asymmetrically; the float on the tilted side is further pulled into the water, increasing buoyancy, while the float on the other side rises, decreasing buoyancy. This generates a restoring moment far greater than that of traditional solutions, significantly improving the overall anti-overturning stability. Compared to existing integral tension leg platforms, this invention employs a modular design, allowing the main float 1 and surface float 2 to be manufactured, transported, and assembled at sea separately. This significantly reduces reliance on large crane vessels and deep-water ports, simplifies installation, and enhances adaptability to sea conditions. Furthermore, since the restoring moment is primarily contributed by the peripheral distributed floats, the structural dimensions and steel consumption of the main float 1 are optimized, reducing manufacturing costs. In addition, the length of the second tension rib 4 can be flexibly adjusted according to the actual water depth, making the entire system significantly more adaptable to changes in water depth than traditional solutions.

[0028] In practical engineering implementation, the number of surface pontoons 2 can be flexibly configured according to the design load, marine environment, and wind turbine capacity. As an exemplary and preferred solution, the number of surface pontoons 2 is set to three, which are evenly distributed at 120° around the circumference of the main buoy 1, forming an equilateral triangle layout. The triangular layout has inherent geometric stability, enabling all-round coverage of restoring moment with the minimum number of pontoons. At the same time, the three pontoons, three second tension ribs 4, and three gravity foundations 5 form a one-to-one force system match, making the force path of the entire system clear, the load distribution uniform, and the structural design most concise and efficient. Of course, the number of surface pontoons 2 is not limited to three. Depending on the sea state level, wind turbine power, and stability requirements of the specific project, it can also be set to four or more, and correspondingly adopt quadrilateral, pentagonal, or other polygonal layout methods. For example, in severe sea conditions with frequent typhoons and high wave heights, increasing the number of buoys can further distribute buoyancy loads and improve system redundancy. Even if a single buoy or connecting cable fails unexpectedly, the remaining buoys can still provide sufficient restoring torque, thereby enhancing the platform's fault tolerance and survivability. At the same time, the layout of more buoys can reduce the buoyancy requirement of a single buoy, thereby reducing the size and manufacturing cost of each buoy, and making it more friendly to transportation and installation operations.

[0029] Among them, the tension-leg mooring employed by the tension ribs is a highly rigid constraint method that is completely different from conventional catenary mooring. Unlike catenary mooring, which relies on the self-weight of the cables to provide restoring force, the pretension of tension-leg mooring makes the tension ribs exhibit extremely high axial stiffness in all degrees of freedom: when the platform is subjected to waves and attempts to move upward (heaving), the tension ribs are further stretched, and the pretension increases sharply, thereby generating a strong downward restoring force; when the platform drifts horizontally or tilts, the geometric changes of the tension ribs also quickly trigger tension adjustment, forming a comprehensive rigid constraint.

[0030] For example, the main buoy 1 includes: A vertically positioned central column 11; A horizontal pontoon 12 is fixedly connected to the lower end of the central column 11; One end of the first tension rib 3 is connected to the water surface buoy 2, and the other end is connected to the end of the horizontal buoy 12; one end of the second tension rib 4 is connected to the end of the horizontal buoy 12, and the other end is connected to the gravity foundation 5.

[0031] Specifically, the central column 11, as the core load-bearing component of the main float 1, supports the wind turbine generator set (including the tower, nacelle, and blades) on its upper part. It also houses multiple ballast tanks, allowing for the injection or discharge of ballast water to adjust the platform's draft and overall attitude, ensuring stable buoyancy during towing, installation, and operation. The horizontal floats 12, located below the central column 11, primarily provide additional buoyancy reserves and, through their large horizontal deployment, offer a greater restoring arm to resist wind-induced overturning moments. In terms of connection method, one end of the first tension rib 3 is connected to the surface buoy 2, and the other end is connected to the end of the horizontal buoy 12. This allows the buoyancy change generated by the surface buoy 2 when the platform tilts to act directly on the far end of the horizontal buoy 12, forming the maximum anti-overturning moment. Similarly, one end of the second tension rib 4 is also connected to the same end of the horizontal buoy 12, and the other end extends downward to the gravity foundation 5 on the seabed. This allows the main buoyancy of the entire platform, the auxiliary buoyancy of the surface buoy 2, and the mooring pretension to all converge at the end node of the horizontal buoy 12, achieving efficient force transmission and balance.

[0032] For example, the horizontal pontoon 12 includes: The main transverse pontoon is fixedly connected to the lower end of the central column at its middle section. A longitudinal buoy, one end of which is fixedly connected to the middle of the main transverse buoy, and the longitudinal buoy is arranged perpendicular to the main transverse buoy.

[0033] Specifically, the horizontal buoy 12 includes a main transverse buoy and a longitudinal buoy. The middle part of the main transverse buoy is fixedly connected to the lower end of the central column 11, allowing the main transverse buoy to extend symmetrically to the left and right sides. One end of the longitudinal buoy is fixedly connected to the middle part of the main transverse buoy (i.e., the two intersect directly below the central column), and the axis of the longitudinal buoy is perpendicular to the axis of the main transverse buoy, forming a regular T-shaped planar configuration. Compared with cross-shaped or triangular horizontal buoys, the T-shaped buoy used in this invention significantly reduces the overall length and wetted surface area of ​​the buoy while satisfying the symmetrical arrangement of the three mooring systems, thereby reducing the amount of steel used and welding work, making the manufacturing cost more economical. At the same time, due to the reduction in the projected area of ​​the underwater buoy, the hydrodynamic load of waves acting on the buoy is also reduced. Especially under high sea states, wave frequency-induced fatigue loads can be effectively suppressed, thereby extending the service life of the structure and reducing the maintenance frequency. In addition, the T-shaped configuration provides a longer restoring arm in the longitudinal direction (main wind direction), while in the transverse direction (crosswind direction), it ensures sufficient torsional stiffness through the symmetrical ends on both sides, which can better adapt to the stress requirements of offshore wind turbines under various wind, wave and flow combinations such as headwind, crosswind and diagonal wind.

[0034] Furthermore, the horizontal pontoons in this invention are not limited to the T-shaped configuration. Depending on the specific marine environment, wind turbine power level, and mooring system configuration requirements, they can also be flexibly designed into other structural forms such as Y-shaped, cross-shaped, or single-arm (I-shaped). For example, the three arms of the Y-shaped horizontal buoy are at 120° angles to each other, which can form a completely symmetrical force system with the three surface buoys 2 and the three sets of tension legs. It is suitable for sea areas where the wind, waves and current directions are relatively uniform, and its force balance is better than that of the T-shaped buoy. The cross-shaped horizontal buoy has four symmetrically distributed arms, which is suitable for use with the four surface buoys 2 and the four sets of tension legs. When the number of buoys increases, the load can be further distributed and the system redundancy can be improved. It is especially suitable for ultra-large wind turbines or extreme sea state conditions. The single-arm (I-shaped) horizontal buoy only retains one main transverse arm, which is the simplest in structure. Although the overall symmetry is weak, in sea areas where the prevailing wind direction and wave direction are very clear (such as monsoon areas), the main mooring system can be concentrated on the single arm facing the direction of the incoming current. This allows sufficient anti-overturning capacity to be achieved with the smallest buoy size and steel consumption, which significantly reduces the platform's self-weight and manufacturing cost. Through the above-mentioned diverse horizontal pontoon selection design, the present invention can be customized to match the water depth conditions, environmental load characteristics and economic objectives of different projects, and achieve the optimal balance between structural efficiency and engineering cost while ensuring the excellent motion performance of the tension leg floating wind turbine.

[0035] For example, triangular reinforcing plates are provided at the connection between the main transverse pontoon and the longitudinal pontoon, as well as at the connection between the main transverse pontoon and the central column 11. Specifically, the triangular reinforcing plates are usually made of steel plates of the same material as the pontoons, and are symmetrically arranged on both sides of the connecting weld. Their right-angled sides are attached to the surface of the intersecting components and are reliably connected to the base material through full penetration or fillet welds. Since the main transverse pontoon, the longitudinal pontoon, and the central column converge in the same area, this area is subjected to complex combined effects of bending moment, shear force, and torsion under the operation of the wind turbine and marine environmental loads, and is a high stress concentration area in the overall structure. The setting of triangular reinforcing plates can effectively expand the load transmission path, disperse the peak stress at the connection to a larger plate thickness range, and avoid premature weld cracking or fatigue crack initiation caused by stress concentration. Meanwhile, the geometry of the triangular reinforcing plate itself can significantly improve the stiffness and buckling resistance of the connection nodes with minimal increase in structural weight, suppress the relative angular deformation between the pontoon and the column under wave alternating loads, thereby protecting the alignment accuracy of the internal ballast tank and tension rib connectors.

[0036] For example, the end of the horizontal float 12 is provided with a first connecting lug and a second connecting lug, the first connecting lug is hinged to the end of the first tension rib 3, and the second connecting lug is hinged to the end of the second tension rib 4.

[0037] The connecting lugs are typically made of high-strength steel and are fixed to the structural reinforcement area at the end of the horizontal pontoon by welding or bolting. The lugs have pin holes. The ends of the tension ribs are fitted with fork-shaped or single-ear joints, forming a hinged connection with the lugs via high-strength pins. This hinged connection ensures that the tension ribs only bear axial tensile force and transmit almost no bending moment or shear force, avoiding additional bending stress within the tension ribs due to the slight rotation of the pontoon under wave action, thus effectively extending the fatigue life of the tension ribs. Simultaneously, connecting the first tension rib 3 (connecting to the surface pontoon 2) and the second tension rib 4 (connecting to the seabed foundation) to two independent lugs allows the load paths of the two sets of tension ribs to be independent, avoiding the superposition of forces at a single connection point, facilitating separate pretension adjustment and replacement maintenance. Furthermore, during installation, the second tension rib 4 can be tensioned and anchored to the gravity foundation 5 first, and then the connecting cable force of the surface pontoon 2 can be adjusted independently through the first connecting lugs, achieving precise step-by-step control.

[0038] For example, the surface pontoon 2 includes a cylindrical body and a lifting lug disposed at the bottom of the cylindrical body, the lifting lug being hinged to the end of the first tension rib 3. On the one hand, the connection point of the first tension rib 3 is located at the bottom of the pontoon, so that the line of action of the tension rib on the pontoon is basically through the vertical center line of the pontoon or slightly below it, which can effectively prevent the pontoon from capsizing or deflecting under the action of tension, and keep the pontoon in a positive floating posture at all times; on the other hand, most of the submerged volume of the pontoon is below the water surface, and the bottom lifting lug is close to the center of buoyancy of the pontoon. When the waves cause the pontoon to rise and fall, the movement amplitude at the lifting lug is relatively small, which helps to reduce the dynamic load amplitude of the first tension rib 3, thereby extending its fatigue life.

[0039] For example, the surface pontoon 2 is internally provided with multiple horizontal baffles, which divide the surface pontoon 2 into multiple independent ballast compartments arranged in a vertical direction; each independent ballast compartment is provided with a ballast water pipeline interface and a vent valve interface that communicate with the outside.

[0040] By setting up horizontal bulkheads, the internal space of the long cylindrical pontoon can be divided into several smaller compartments. When one compartment is damaged and flooded due to collision or corrosion, the other compartments can still maintain their airtightness and buoyancy, thus preventing the entire pontoon from losing buoyancy and failing, significantly improving the system's damage stability and redundancy safety. On the other hand, operators can independently inject or discharge ballast water into each independent compartment through the ballast water pipeline interface, and adjust the air pressure inside the compartment in conjunction with the vent valve interface, achieving precise control over the overall draft, buoyancy, and tilt attitude of the surface pontoon 2. For example, during towing, the ballast can be appropriately increased to lower the center of gravity and improve wind and wave resistance; after installation, the ballast can be reduced to increase the buoyancy contribution and restoring torque; and when maintenance or replacement of the first tension rib 3 is required, the relative tension between the pontoon and the main buoy 1 can be changed by adjusting the ballast. In addition, multiple horizontal baffles also act as reinforcing ribs, significantly improving the buckling resistance of the thin-walled cylinder under changes in external water pressure and internal ballast, so that the pontoon can maintain its circular cross-sectional shape without instability and deformation when subjected to hydrostatic pressure at greater depths.

[0041] For example, the gravity foundation 5 includes a concrete base and a connecting anchor ring embedded in the concrete base, and the end of the second tension bar 4 is connected to the connecting anchor ring.

[0042] Specifically, the gravity foundation 5 uses a large-volume concrete base as its main structure. Before concrete pouring, the connecting anchor ring is precisely pre-embedded in a predetermined position inside the base. The end of the second tension reinforcement 4 is reliably connected to the connecting anchor ring through shackles, connecting chains, or direct pins. The concrete base relies on its own enormous weight and the frictional force and anti-slip capability generated between itself and the seabed to resist the upward pretension of the second tension reinforcement 4 and the horizontal environmental load. Unlike pile foundations, it does not require deep piling operations, thus having a wider range of adaptability to seabed geological conditions. Whether it is a sandy, gravelly, or hard clay seabed, it can be placed after proper leveling and bedding treatment.

[0043] In practical engineering applications, the specific form of seabed foundation is not limited to gravity foundation 5. It can be flexibly selected according to the geological survey results and construction conditions of the project sea area. For example, suction pile foundation, rock anchor foundation or pile group foundation can all form a reliable connection with the second tension bar 4 of the present invention. Specifically, suction pile foundations (also known as suction anchors or suction piles) are large-diameter steel cylinders that are closed at the top and open at the bottom. By pumping water to create a pressure difference between the inside and outside, they are "sucked" into the seabed to a predetermined depth. They are suitable for relatively homogeneous strata such as sand and soft clay, and have the outstanding advantages of fast installation, no need for large piling equipment, and minimal impact on marine noise. Rock anchor foundations are anchor points formed by drilling holes in the seabed bedrock, inserting high-strength anchor rods, and pouring bonding materials. They are particularly suitable for hard seabeds (such as rock or dense soil layers) where gravity or suction piles cannot be used. They have high tensile strength and good long-term stability. Pile group foundations consist of multiple steel pipe piles or concrete piles driven into the deep seabed in a certain layout and connected to tension legs through a top cap. They are suitable for sea areas with thick soft soil layers and insufficient single pile bearing capacity. The coordinated work of pile groups can provide great tensile and horizontal resistance.

[0044] The second objective of this invention is to provide an installation method for a combined tension leg floating fan, comprising the following steps: The gravity foundations 5 are respectively installed at the first preset positions on the seabed; The main buoy 1 and the wind turbine installed on its upper end were transported as a whole to the installation sea area; Connect one end of each of the second tension ribs 4 to the main float 1, connect the other end of each of the second tension ribs 4 to the corresponding gravity foundation 5, and apply pretension to each of the second tension ribs 4. Transport the multiple surface pontoons 2 to the second preset position corresponding to the outer periphery of the main buoy 1; One end of each of the first tension ribs 3 is connected to the corresponding surface float 2, and the other end of each of the first tension ribs 3 is connected to the main float 1, and pretension is applied to each of the first tension ribs 3.

[0045] Among them, the gravity foundation 5, the main float 1, and the surface pontoons 2 can be prefabricated on land or assembled in the port, and transported to the installation area in batches by ordinary tugboats or barges. Unlike traditional integral tension leg platforms, they do not rely on large deep-water crane vessels and special dry docks, which greatly reduces the dependence on port facilities and special vessels. During the installation process, the gravity foundation 5 is first accurately positioned and settled and stabilized. Then, the second tension rib 4 and the first tension rib 3 are tensioned in stages, so that the pretension of the two sets of mooring systems can be independently controlled and mutually checked, avoiding construction risks caused by structural center of gravity shift or sudden changes in sea conditions during the overall hoisting. At the same time, the installation and connection of the surface pontoons 2 are carried out after the main float 1 has been initially fixed. At this time, the main float 1 itself has a certain degree of stability, providing a stable benchmark for the accurate positioning of the outer pontoons, further reducing the difficulty of underwater docking. Compared with existing technologies, this method decomposes the installation of complex large structures into multiple relatively simple modular operations. The requirements for the lifting capacity of construction vessels and the sea conditions of operation are significantly reduced in each step, thereby shortening the offshore construction window and reducing the use time of high-cost dynamic positioning vessels. While ensuring installation accuracy, it effectively reduces the construction cost, time cost and environmental risks of the entire project, and is especially suitable for deep-sea wind power development scenarios that lack deep-water ports.

[0046] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A combined tension leg floating fan, characterized in that, include: The main float (1) is equipped with a fan at its upper end; Multiple surface buoys (2) are arranged around the outer periphery of the main buoy (1); Multiple first tension ribs (3), one end of the first tension rib (3) is connected to a water surface float (2), and the other end is connected to the main float (1); Multiple second tension ribs (4); Multiple gravity foundations (5) are provided on the seabed; one end of the second tension rib (4) is connected to the main buoy (1), and the other end is connected to one of the gravity foundations (5).

2. The combined tension leg floating fan according to claim 1, characterized in that, The number of the surface pontoons (2) is three, and the three surface pontoons (2) are evenly arranged around the circumference of the main buoy (1).

3. A combined tension leg floating fan according to claim 1, characterized in that, The main floating body (1) includes: A vertically installed central column (11); A horizontal pontoon (12) is fixedly connected to the lower end of the central column (11); One end of the first tension rib (3) is connected to the surface buoy (2), and the other end is connected to the end of the horizontal buoy (12); one end of the second tension rib (4) is connected to the end of the horizontal buoy (12), and the other end is connected to the gravity foundation (5).

4. A combined tension leg floating fan according to claim 3, characterized in that, The horizontal pontoon (12) includes: The main transverse pontoon is fixedly connected to the lower end of the central column at its middle section. A longitudinal buoy, one end of which is fixedly connected to the middle of the main transverse buoy, and the longitudinal buoy is arranged perpendicular to the main transverse buoy.

5. A combined tension leg floating fan according to claim 4, characterized in that, Triangular reinforcing plates are provided at the connection between the main transverse pontoon and the longitudinal pontoon, as well as at the connection between the main transverse pontoon and the central column (11).

6. A combined tension leg floating fan according to claim 3, characterized in that, The horizontal pontoon (12) is provided with a first connecting lug and a second connecting lug at its end. The first connecting lug is hinged to the end of the first tension rib (3), and the second connecting lug is hinged to the end of the second tension rib (4).

7. A combined tension leg floating fan according to claim 1, characterized in that, The surface pontoon (2) includes a cylinder and a lifting lug located at the bottom of the cylinder, the lifting lug being hinged to the end of the first tension rib (3).

8. A combined tension leg floating fan according to claim 1, characterized in that, The surface pontoon (2) is provided with multiple horizontal partitions at intervals inside, which divide the surface pontoon (2) into multiple independent ballast compartments arranged in the vertical direction; each independent ballast compartment is provided with a ballast water pipeline interface and a vent valve interface that communicate with the outside.

9. A combined tension leg floating fan according to claim 1, characterized in that, The gravity foundation (5) includes a concrete base and a connecting anchor ring embedded in the concrete base, and the end of the second tension bar (4) is connected to the connecting anchor ring.

10. The installation method of a combined tension leg floating fan according to claim 1, characterized in that, Includes the following steps: Multiple gravity foundations (5) are respectively installed at first preset positions on the seabed; The main buoy (1) and the wind turbine installed on its upper end are transported as a whole to the installation sea area; Connect one end of each of the second tension ribs (4) to the main float (1), connect the other end of each of the second tension ribs (4) to the corresponding gravity foundation (5), and apply pretension to each of the second tension ribs (4); Transport multiple of the surface pontoons (2) to the second preset position corresponding to the outer periphery of the main buoy (1); Connect one end of each of the first tension ribs (3) to the corresponding surface float (2), connect the other end of each of the first tension ribs (3) to the main float (1), and apply pretension to each of the first tension ribs (3).

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