Tension leg spiral anchor set system and full-submersible type offshore wind turbine platform

Abstract

The invention discloses a tension leg spiral anchor set system and a full-submersible type offshore wind turbine platform. The tension leg spiral anchor set system comprises a tension leg set and a spiral anchor set. The upper part of the tension leg group is used for loading the floating platform, and the lower part is connected with the spiral anchor group; the spiral anchor set comprises a plurality of spiral anchor pairs rotating in the reverse direction, each spiral anchor comprises a bottomless steel pipe pile and a plurality of spiral discs, the spiral discs of every two adjacent spiral anchors are opposite in direction, and the spiral anchor pairs rotating in the reverse direction are formed. The tension leg set provides pulling force for limiting horizontal and vertical motion response of the floating platform, and the spiral anchor set provides pulling force for fixing the bottom ends of the tension legs. Due to the fact that the spiral anchor is provided with the spiral disc, the uplift bearing capacity of the spiral anchor is greatly improved. And meanwhile, the design of the spiral anchor pairs rotating in the reverse direction is adopted, subsea construction is facilitated, the tension leg spiral anchor set system is adopted by the full-submersible type offshore wind turbine platform, the stability and reliability of all parts of equipment can be greatly improved, and the service life of all the parts of the equipment can be greatly prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of offshore wind power generation, and in particular relates to a tension leg spiral anchor group system and a fully submersible offshore wind turbine platform. Background Art

[0002] The existing floating offshore wind turbine mooring systems mainly have the problems of low space utilization and high mooring costs. For example, the water depth of the Three Gorges Leader is about 40 meters, but its catenary length is 600-800 meters, which not only wastes space but also increases costs. In addition, the catenary mooring method currently used by floating wind turbines cannot limit the vertical displacement of the platform, causing the vertical translation and rotation of the wind turbine to be too large in sea areas with large tidal changes, which is not conducive to the stable operation of the wind turbine equipment.

[0003] The tension leg mooring method can effectively limit the vertical translation and rotation of the platform. However, most traditional tension leg moorings use semi-submersible floating platforms. Under the change of tide level, the vertical displacement of the semi-submersible platform is large, resulting in drastic changes in the tension of the tension leg. At high tide, there is a risk of the tension leg being broken; at low tide, the tension of the tension leg may become zero or become pressure, which makes the tension leg at risk of buckling instability.

[0004] Tension leg mooring has high requirements for the pull-out bearing capacity of the anchor foundation, but traditional plate anchors, large grip anchors, suction anchors, torpedo anchors, pile anchors, etc. cannot meet the requirements. If the pull-out bearing capacity of the traditional anchor foundation is increased by increasing the size, it will not only lead to excessively high costs, but also difficult to install and difficult to achieve.

[0005] Therefore, it is necessary to propose an integrated design scheme for offshore wind turbine floating platforms and mooring anchoring systems suitable for sea areas with large water level changes, in order to solve the above problems economically, reasonably and effectively. Summary of the invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a tension leg spiral anchor group system, so that the floating wind turbine platform in the sea area with large water level changes has good stability, the space utilization rate of the mooring system is high, the bearing capacity of the anchoring system is improved and the cost is reduced, and a fully submersible offshore wind turbine platform is realized.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A first aspect of the present invention is a tension leg helical anchor group system, comprising a tension leg group and a helical anchor group;

[0009] The upper part of the tension leg group is used to load the floating platform, and the lower part is connected to the spiral anchor group; the spiral anchor group includes multiple pairs of spiral anchors rotating in opposite directions, each spiral anchor includes a bottomless steel pipe pile and a plurality of spiral discs, and the spiral discs of two adjacent spiral anchors are in opposite directions, forming a pair of spiral anchors rotating in opposite directions; the tension leg group provides tension for limiting the horizontal and vertical movement response of the floating platform, and the spiral anchor group provides tension for fixing the bottom end of the tension leg.

[0010] Since the spiral anchor is equipped with a spiral plate, its pull-out bearing capacity is greatly improved. At the same time, the reverse-rotating spiral anchor pair design is adopted, which is conducive to underwater construction.

[0011] In one embodiment, the floating platform may be a fully submersible or semi-submersible platform, that is, the tension leg spiral anchor group system of the present invention is applicable to both semi-submersible platforms and fully submersible platforms, which fully demonstrates that it can ensure the stability of the anchor foundation under tension changes.

[0012] In one embodiment, the tension leg group includes a plurality of tension bars and connecting keys and ball joints matched with the tension bars; each tension bar is connected to the floating platform through the connecting key and to the spiral anchor group through the ball joint, and the ball joint only limits the translation of the bottom end of the tension bar and the top end of the bottomless steel pipe pile, and does not limit the rotation of the top end of the bottomless steel pipe pile at the bottom end of the tension bar.

[0013] In one embodiment, the screw disk is made of steel and is welded to at least the middle and lower parts of the bottomless steel pipe pile.

[0014] The second aspect of the present invention is a fully submersible offshore wind turbine platform, which is also a specific application of the tension leg spiral anchor group system of the first aspect. The fully submersible offshore wind turbine platform includes a floating wind turbine device and a fully submersible platform and the tension leg spiral anchor group system of the first aspect of the present invention; the fully submersible platform is arranged below the sea level, the upper part is connected to the floating wind turbine device to provide buoyancy for the floating wind turbine device, the lower part is connected to the tension leg group, the spiral anchor group is buried in the seabed, the top of which is exposed to a certain distance from the seabed and connected to the tension leg group.

[0015] Since the fully submersible platform is below sea level, the overall structure of the floating wind turbine equipment and the fully submersible platform has an extremely small waterline area. In this case, the sea wave force on the platform can be greatly reduced, the platform stability is increased, and the impact of water level changes on buoyancy is extremely small. The platform is not prone to vertical displacement, and the tension leg tension change range is extremely small, which can greatly improve the stability, reliability and service life of various parts of the equipment.

[0016] In one embodiment, the fully submersible platform includes a central column, three ballast columns, three ballast cross tubes and a central ballast cylinder; the upper part of the central column is connected to the floating wind turbine equipment, and the lower part is connected to the central ballast cylinder, and the three ballast columns are connected to the central ballast cylinder through three ballast cross tubes.

[0017] In one embodiment, the fully submersible platform further includes: three diagonal braces, one end of each of the three diagonal braces is connected to the central column, and the other end is respectively connected to three ballast columns, and the end connected to the central column is higher than the end connected to the column.

[0018] In one embodiment, the three ballast columns are located at three vertices of an equilateral triangle, and the central ballast cylinder is located at the center of the equilateral triangle.

[0019] In one embodiment, the internal spaces of the three ballast columns, three ballast cross tubes and one central ballast cylinder are interconnected, and store a certain amount of ballast water. By adjusting the quality of the ballast water, it is ensured that the fully submersible platform is still below the sea level at the lowest water level, and the waterline area is only the outer diameter cross section of the central column.

[0020] In one embodiment, the ballast water is injected and discharged through a ballast water pump, and the tensioning force on the tension tendon is monitored by a tension monitoring system arranged on the connection key. When the tensioning force is not within a set threshold range, the mass of the ballast water is adjusted by the ballast water pump to adjust the weight of the platform, thereby achieving the effect of adjusting the tensioning force of the tension tendon, so that the tension change of the tension tendon is within a set range.

[0021] In one embodiment, the fully submersible platform is a concrete structure to provide its own weight.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention proposes a scheme combining a tension leg group mooring system with a spiral anchor group anchoring system. The presence of the spiral disk greatly improves the pull-out bearing capacity of the spiral anchor, ensuring the safety of the anchor foundation under tension changes; at the same time, the spiral anchor is small in size, which can reduce the material cost of the anchor foundation.

[0024] The present invention proposes an installation method for spiral anchors that combines simultaneous reverse rotation and pressing, which not only reduces installation resistance but also eliminates torque reaction force of construction equipment, thereby reducing the construction cost of the anchor foundation and achieving cost reduction and efficiency improvement of the anchor foundation.

[0025] The fully submersible platform proposed in the present invention ensures that the platform is always below sea level by adjusting the ballast water volume, and the waterline area is only the cross-section of the outer diameter of the central column. Therefore, the sea wave force on the platform is greatly reduced, thereby increasing the stability of the platform. At the same time, the buoyancy change caused by the water level change is also smaller, and the vertical displacement of the platform is smaller.

[0026] The present invention proposes a solution combining a fully submersible platform with a tension leg group mooring system, so that the tension variation of the tension leg is small, thereby ensuring the safety of the tension leg and also ensuring the vertical stability of the wind turbine in sea areas with large tidal changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification are used to explain the principles of the present application, and do not constitute an improper limitation on the present application.

[0028] Figure 1 The figure is a detailed structural diagram of a tension leg and a spiral anchor group in the tension leg spiral anchor group system of the present invention.

[0029] Figure 2 This is a detailed structural diagram of a spiral anchor pair of the present invention.

[0030] Figure 3 It is a schematic structural diagram of a fully submersible offshore wind turbine platform of the present invention.

[0031] Figure 4 It is a detailed structural diagram of the fully submersible platform of the present invention.

[0032] In the figure:

[0033] 1. Floating wind turbine equipment; 2. Fully submersible platform; 3. Tension leg group; 4. Screw anchor group; 201. Center column; 202. Diagonal brace; 203. Ballast column; 204. Ballast cross pipe; 205. Center ballast cylinder; 301. Connecting key; 302. Tension bar; 303. Ball joint; 400. Screw anchor pair; 401. Bottomless steel pipe pile; 402. Screw plate. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0035] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0038] Traditional tension leg mooring not only has high requirements for anchor foundation, but also the tension of the tension leg varies greatly at different tide levels and lacks stability. To this end, the present invention provides a tension leg spiral anchor group system, see Figure 1 and Figure 2 It mainly includes two parts: a tension leg group 3 and a spiral anchor group 4.

[0039] The spiral anchor group 4 includes a plurality of pairs of spiral anchors 400 that rotate in opposite directions. Each spiral anchor includes a bottomless steel pipe pile 401 and a plurality of spiral discs 402. The spiral discs 402 of two adjacent spiral anchors are in opposite directions, forming a pair of spiral anchors 400 that rotate in opposite directions. Figure 1 Two pairs of helical anchor pairs 400 are shown.

[0040] The lower part of the tension leg group 3 is connected to the spiral anchor group 4, and is located directly above the spiral anchor group 4, and is used to carry a floating platform, which can be fully submersible or semi-submersible, and is connected to the upper part of the tension leg group 3. The tension leg group 3 provides tension to limit the horizontal and vertical movement response of the floating platform, and the spiral anchor group 4 can provide tension to fix the bottom end of the tension leg.

[0041] Please continue to refer to Figure 1 The tension leg group 3 is composed of a number of tension legs, each of which includes a connection key 301, a tension bar 302 and a ball joint 303. The connection key 301 and the ball joint 303 are matched with the tension bar 302. The connection key 301 is located at the top of the tension bar 302 and is used to connect with the bottom of the floating platform. The ball joint 303 is located at the bottom of the tension bar 302 and is connected to the lower spiral anchor group 4. The ball joint 303 only limits the translation of the bottom of the tension bar 302, but does not limit its rotation, so as to prevent the tension bar 302 from being damaged by excessive shear force. When the platform is working, the tension bar 302 always maintains a tensioned state and bears a large tension force to limit the displacement of the floating platform. The connection between the connection key 301 and the tension bar 302 adopts the existing technology, and the present invention will not repeat this aspect.

[0042] In some embodiments of the present invention, the tension bar 302 is preferably made of a hollow steel tube, and the buoyancy it receives is controlled to be equal to the gravity, so that the tension bar 302 is balanced and only bears the tensioning force from the floating platform, thereby increasing the safety of the tension bar 302.

[0043] Please continue to refer to Figure 2 The spiral anchor group 4 is composed of a number of spiral anchors, each of which includes a bottomless steel pipe pile 401 and two screw discs 402. The screw discs 402 can be made of steel and welded to the bottom and middle of the bottomless steel pipe pile 401. When the spiral anchor 402 bears the tension force transmitted by the tension bar, the anti-pulling force provided by the spiral anchor is not only the friction between the bottomless steel pipe pile 401 and the soil, but also the bite force between the screw disc 402 and the soil body, which can expand the bearing range of the spiral anchor and greatly increase the anti-pulling bearing capacity of the spiral anchor, especially for the vertical pull-out force transmitted by the tension leg floating platform. Under the premise of ensuring the safety of the platform, the size of the main pile can be reduced and the cost can be reduced. Each tension bar 302 is connected to the top of the bottomless steel pipe pile 401 of a spiral anchor through its ball joint 303. The ball joint 303 only limits the translation of the bottom end of the tension bar 302 and the top of the bottomless steel pipe pile 401, and does not limit the rotation of the bottom end of the tension bar 302 and the top of the bottomless steel pipe pile 401. The connection between the tension bar 302, the ball joint 303 and the bottomless steel pipe pile 401 all adopts the existing technology, and the present invention will not elaborate on this aspect.

[0044] For example, in the embodiment of the present invention, the screw disk 402 is a spiral structure made of steel, such as a blade-type screw disk. The screw disk 402 is welded to the middle and lower parts of a bottomless steel pipe pile 401 respectively. The screw disks 402 on the same bottomless steel pipe pile 401 are in the same direction, and the screw disks 402 on two adjacent bottomless steel pipe piles 401 are in opposite directions. During installation, they are pressed in by rotating in opposite directions at the same time to eliminate the torque reaction force of the construction equipment.

[0045] The focus of the present invention is to propose a solution of combining a tension leg group mooring system with a spiral anchor group anchoring system for the large vertical pull-out force transmitted to the anchor foundation by the tension leg platform. The presence of the screw disk 402 greatly improves the vertical pull-out bearing capacity of the spiral anchor pair 400. The installation of the spiral anchor pair 400 is an installation method that combines simultaneous reverse rotation and pressing. Compared with the traditional driven installation of steel pipe piles, the installation method of the present invention not only reduces the installation resistance, but also eliminates the torque reaction force of the construction equipment, thereby reducing the construction cost of the anchor foundation and achieving cost reduction and efficiency improvement of the anchor foundation.

[0046] Based on the above tension leg screw anchor system, the present invention also provides a fully submersible offshore wind turbine platform, referring to Figure 3As shown, it includes a floating wind turbine device 1, a fully submersible platform 2, and a tension leg screw anchor group system consisting of a tension leg group 3 and a screw anchor group 4. The fully submersible platform 2 is arranged below the sea level, the upper part is connected to the floating wind turbine device 1 to provide buoyancy for it, and the lower part is connected to the tension leg group 3. The screw anchor group 4 is vertically buried and anchored on the seabed, and the top is exposed to a certain distance from the seabed.

[0047] In the fully submersible offshore wind turbine platform, the buoyancy provided by the fully submersible platform 2 is used to bear the self-weight of the fully submersible platform 2 and the load of the floating wind turbine equipment 1, and secondly, to make the tension leg group 3 bear a tensioning force, thereby limiting the displacement of the platform; and the tensioning force of the tension leg group 3 is borne by the anchoring force provided by the bottom spiral anchor group 4. Due to the presence of the anchor plate 402, the vertical pull-out bearing capacity that the spiral anchor can provide is greatly increased, thereby reducing the cost of the platform while ensuring the safety of the platform.

[0048] In the embodiments of the present invention, see Figure 4 The fully submersible platform 2 includes a central column 201, three ballast columns 203, three ballast transverse tubes 204 and a central ballast cylinder 205. The lower part of the central column 201 is connected to the central ballast cylinder 205, and the upper part is connected to the floating wind turbine device 1. The three ballast columns 203 are connected to the central ballast cylinder 205 through three ballast transverse tubes 204. Preferably, the three ballast columns 203 are located at the three vertices of an equilateral triangle, and the central ballast cylinder 205 is located at the center of the equilateral triangle. The internal spaces of the ballast columns 203, the ballast transverse tubes 204 and the central ballast cylinder 205 are connected and store a certain amount of ballast water. For the convenience of connection, the ballast columns 203 in this embodiment are shaped as hollow cubes, and the central ballast tube 205 is shaped as a hollow hexagonal column. The ballast columns 203 and the central ballast tube 205 provide most of the buoyancy and ballast space of the platform, while the ballast cross tube 204 is a hollow cuboid, which serves to connect the three ballast columns 203 and the ballast central tube 205, and also provides a certain amount of buoyancy and ballast space. The ballast water is injected and discharged by a ballast water pump, and the tension force on the tension bar 302 is monitored by a tension monitoring system set on the connection key 301. When the tension force is too large or too small, the weight of the platform can be adjusted by adjusting the mass of the ballast water, and finally the tension force of the tension bar is adjusted, so that the tension change of the tension bar is within a certain range, ensuring the safety of the tension leg.

[0049] Furthermore, in this embodiment, the fully submersible platform 2 further includes three diagonal braces 202, the higher ends of the three diagonal braces 202 are connected to the central column 201, and the lower ends are respectively connected to three ballast columns 203. Each diagonal brace 202 is located directly above a ballast cross pipe 204. By providing three diagonal braces 202, the lateral load on the upper floating wind turbine equipment 1 is transferred to the ballast columns 203 at the bottom of the platform, thereby improving the stress condition of the platform and increasing the overall rigidity of the platform.

[0050] The fully submersible platform 2 in this embodiment has the following characteristics: Different from the traditional tension leg platform, the fully submersible tension leg platform of the present application is always below the sea level, and the waterline area is only the outer diameter cross-section of the central column. On the one hand, it reduces the size of the sea wave force on the platform, increases the stability of the platform, and reduces the platform motion response, thereby improving the power generation efficiency of the wind turbine; on the other hand, it makes the buoyancy change caused by the water level change smaller, so that the tension change amplitude of the tension leg is smaller, ensuring the safety of the tension leg, and the size of the tensioning force of the tension leg can be adjusted by adjusting the quality of the ballast water in the platform, thereby improving the safety and stability of the platform and reducing the cost of platform construction.

[0051] The fully submersible platform 2 of the present invention may be constructed of concrete to provide its own weight.

[0052] The bottom end of the central ballast cylinder 205 can be connected to a plurality of tension bars 302 via a plurality of connection keys 301 , four of which are shown in the figure.

[0053] The present invention uses a fully submersible platform 2 to provide buoyancy for a floating wind turbine device 1, and its small water plane reduces the influence of water level changes on the system; the tension leg group 3 is used to limit the fully submersible displacement and has large vertical and horizontal rigidity; the spiral anchor group 4 is buried in the seabed and can provide the tension required to fix the bottom end of the tension leg. The present invention is suitable for floating offshore wind turbines in sea areas with large water level changes.

[0054] The specific steps of installing and constructing the fully submersible offshore wind turbine platform of this embodiment are as follows:

[0055] S1: Install the central column 201, the diagonal brace 202, the ballast column 203, the ballast cross pipe 204, and the central ballast cylinder, connect them into a structure, and use wet towing to the installation position to form a floating platform;

[0056] S2: A plurality of spiral anchor pairs 400 are vertically anchored on the seabed by a combination of rotation and pressing, so as to realize the installation of the bottom anchor foundation;

[0057] S3: adjusting the mass of the ballast water in the fully submersible platform 2 so that the fully submersible platform is in a pre-installation floating state, that is, when the platform is at the installation depth, the buoyancy and gravity are as close as possible;

[0058] S4: Install the tension bar 302, which is connected to the fully submersible platform 2 through the connecting key 301 and connected to the lower spiral anchor group 4 through the ball joint 303;

[0059] S5: Adjust the mass of the ballast water in the fully submersible platform 2 so that each tension bar 302 is in a tensioned state to ensure the stability of the platform during the installation process.

[0060] S6: Hoist the floating wind turbine equipment 1 onto the fully submersible platform 2. During the hoisting process, the mass of the ballast water in the fully submersible platform 2 is adjusted so that the tension force of the tension tendons 302 always meets the requirements.

[0061] From the above, it can be seen that the fully submersible offshore wind turbine platform and the tension leg spiral anchor mooring anchor system provided in this example, by making the platform always below the water surface and reducing the waterline area of ​​the platform, on the one hand, reduce the size of the wave force on the platform, reduce the motion response of the platform, and thus improve the power generation efficiency of the wind turbine; on the other hand, the buoyancy change caused by the water level change is small, so that the tension change amplitude of the tension leg is small, ensuring the safety of the tension leg, and improving the safety of the platform as a whole. At the same time, the bottom anchor adopts a spiral anchor. For the vertical pulling force transmitted from the tension leg to the anchor foundation, the spiral anchor causes the screw plate and the soil to bite each other, which can greatly improve its vertical pull-out resistance and greatly reduce the cost of the anchor foundation. In addition, the installation of the spiral anchor pair is an installation method that combines simultaneous reverse rotation and pressing. Compared with the traditional steel pipe pile driving installation, the installation method of the present invention not only reduces the installation resistance, but also eliminates the torque reaction force of the construction equipment, which can reduce the construction cost of the anchor foundation.

[0062] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A tension leg screw anchor system, characterized in that: It includes a tension leg group (3) and a spiral anchor group (4); The upper part of the tension leg group (3) is used to load the floating platform, and the lower part is connected to the spiral anchor group (4); the spiral anchor group (4) includes a plurality of pairs of spiral anchors (400) that rotate in opposite directions, each spiral anchor includes a bottomless steel pipe pile (401) and a plurality of spiral discs (402), and the spiral discs (402) of two adjacent spiral anchors are in opposite directions, forming a pair of spiral anchors (400) that rotate in opposite directions; the tension leg group (3) provides tension for limiting the horizontal and vertical movement response of the floating platform, and the spiral anchor group (4) provides tension for fixing the bottom end of the tension leg.

2. The tension leg screw anchor system according to claim 1, characterized in that: The floating platform is a fully submersible or semi-submersible platform.

3. The tension leg screw anchor system according to claim 1, characterized in that: The tension leg group (3) comprises a plurality of tension bars (302) and a connecting key (301) and a ball joint (303) matched with the tension bars (302); each tension bar (302) is connected to the floating platform via the connecting key (301) and to the spiral anchor group (4) via the ball joint (303); the ball joint (303) only limits the translation of the bottom end of the tension bar (302) and the top end of the bottomless steel pipe pile (401), but does not limit the rotation of the bottom end of the tension bar (302) and the top end of the bottomless steel pipe pile (401).

4. The tension leg screw anchor system according to claim 1, characterized in that: The screw disk (402) is made of steel and is a blade-type screw disk in a spiral shape. It is welded to the middle and lower parts of the bottomless steel pipe pile (401). The screw disks (402) on two adjacent bottomless steel pipe piles (401) are in opposite directions, forming a pair of spiral anchors that rotate in opposite directions. During installation, they are pressed in by rotating in opposite directions at the same time to eliminate the torque reaction force of the construction equipment.

5. A fully submersible offshore wind turbine platform, characterized in that: The invention comprises a floating wind turbine device (1) and a fully submersible platform (2) and a tension leg helical anchor group system as claimed in any one of claims 1 to 4; the fully submersible platform (2) is arranged below the sea level, the upper part of which is connected to the floating wind turbine device (1) to provide buoyancy for the floating wind turbine device (1), and the lower part of which is connected to the tension leg group (3); the helical anchor group (4) is buried in the seabed, the top of which is exposed to a certain distance from the seabed and is connected to the tension leg group (3).

6. The fully submersible offshore wind turbine platform according to claim 5, characterized in that: The fully submersible platform (2) comprises a central column (201), three ballast columns (203), three ballast transverse pipes (204) and a central ballast cylinder (205); the upper part of the central column (201) is connected to the floating wind turbine equipment (1), and the lower part is connected to the central ballast cylinder (205); the three ballast columns (203) are connected to the central ballast cylinder (205) via three ballast transverse pipes (204).

7. The fully submersible offshore wind turbine platform according to claim 6, characterized in that: The fully submersible platform (2) further comprises: three diagonal braces (202), one end of each of the three diagonal braces (202) being connected to the central column (201), and the other end of each of the three diagonal braces being connected to three ballast columns (203), and the end connected to the central column (201) being higher than the end connected to the column (203).

8. The fully submersible offshore wind turbine platform according to claim 6, characterized in that: The three ballast columns (203) are located at the three vertices of an equilateral triangle, and the central ballast cylinder (205) is located at the center of the equilateral triangle.

9. The fully submersible offshore wind turbine platform according to claim 6, characterized in that: The internal spaces of the three ballast columns (203), the three ballast cross pipes (204) and the central ballast cylinder (205) are interconnected and store a certain amount of ballast water. By adjusting the quality of the ballast water, it is ensured that the fully submersible platform (2) is still below the sea level at the lowest water level, and the waterline area is only the outer diameter section of the central column (201).

10. The fully submersible offshore wind turbine platform according to claim 9, characterized in that: The ballast water is injected and discharged through a ballast water pump, and the tension force applied to the tension tendon (302) is monitored by a tension monitoring system arranged on the connection key (301). When the tension force is not within a set threshold range, the mass of the ballast water is adjusted through the ballast water pump to adjust the weight of the platform, thereby achieving the effect of adjusting the tension force of the tension tendon, so that the tension change of the tension tendon is within a set range.

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