CN116292125B - A three-floating fully submersible wind turbine foundation structure at sea - Google Patents

Abstract

The present invention relates to the field of offshore wind power generation technology, specifically, to an offshore three-floating fully submersible wind turbine foundation structure, including a floating structure, the floating structure including a column, three base columns, a plurality of lateral buoys, a lower support rod and an upper support rod; the length direction of the base column and the column is consistent, and the three base columns are distributed in a circular array around the column, and two adjacent base columns are connected by lateral buoys; the upper part of each base column is connected to the upper part of the column through an upper support rod, and the lower part of each base column is connected to the lower part of the column through a lower support rod. The present application is designed in this way, the overall structure of the wind turbine foundation structure is more regular, the force is more stable and uniform, and the integrity is strong. It is located below the water surface in the working state, and the waterline area of the wind turbine foundation structure is small, so that the wave load is greatly reduced, and the movement of each degree of freedom of the wind turbine under the action of waves can be reduced, and the overall rigidity and stability of the wind power platform can be improved.

Description

A three-floating fully submersible wind turbine foundation structure at sea

Technical Field

The present invention relates to the technical field of offshore wind power generation, and in particular to an offshore three-floating fully submersible wind turbine foundation structure.

Background technique

The limited energy resources and the seriousness of environmental pollution make optimizing the energy structure and developing clean energy the most important tasks at present. Wind energy is a new clean energy that has been widely valued by countries around the world. my country has a coastline of more than 18,000 kilometers and an available sea area of 3 million square kilometers. It has abundant offshore wind energy resources and is not restricted by terrain and urban planning. Since offshore wind power is usually close to energy consumption centers and has better wind resources than onshore wind power, the utilization and development of wind power is gradually shifting from land to sea, showing an accelerating development trend.

According to the different sea areas and the influence of economic factors, offshore wind turbine foundations are divided into fixed foundations and floating foundations. Offshore fixed wind turbines have high construction costs, complex installation processes, large disassembly workloads, and are only applicable to shallow water areas near the coast. In contrast, offshore floating wind turbines are easy to disassemble and recycle, and can be built in deep sea areas far from the coast. The farther from the coast, the higher the wind energy density. Under the same power generation, the power generation capacity of floating wind turbines can be increased by 10% to 20% compared to fixed wind turbines. Therefore, countries around the world have further accelerated the exploration of wind energy in the deep sea, and designed corresponding types of floating wind turbines for different sea areas and functions, and have successively carried out in-depth research.

At present, the development of offshore wind power technology in my country mainly involves shallow water fixed wind turbines, but the wind speed in deep sea areas is sufficiently stable and the wind energy density is high. In addition, the space requirements and acoustic impact on residents have further pushed the demand for offshore wind farms from shallow water areas to deeper coastal deep waters. Offshore floating wind turbines are mainly composed of floating foundations, mooring systems, wind turbines and towers. The design concept of the floating foundation is derived from the platform design of oil development technology. At present, several types of floating foundations can be used: column type, semi-submersible, tension leg platform and barge type. However, the existing floating foundation has a large degree of freedom under the action of waves, and the overall rigidity and stability of the wind power platform are insufficient.

Summary of the invention

The object of the present invention is to provide an offshore three-floating fully submersible wind turbine foundation, which can reduce the movement of various degrees of freedom of the wind turbine under the action of waves and improve the overall rigidity and stability of the wind power platform.

The technical solution of the present invention is achieved in this way:

An offshore three-floating fully submersible wind turbine foundation structure comprises a floating structure, wherein the floating structure comprises a column, three foundation columns, a plurality of lateral buoys, a lower support rod and an upper support rod;

The length directions of the base column and the upright column are consistent, and three base columns are distributed in a circular array around the upright column, and two adjacent base columns are connected by the lateral buoys;

The upper part of each base column is connected to the upper part of the upright column through the upper support rod, and the lower part of each base column is connected to the lower part of the upright column through the lower support rod.

In the working state, the top of the column is higher than the top of the base column, and the bottom of the column is higher than the bottom of the base column.

Furthermore, the three upper support rods are distributed in a circular array around the column, and the three lower support rods are distributed in a circular array around the column.

Furthermore, there are six lateral buoys in total, and the tops of two adjacent base columns are connected by the lateral buoys, and the bottoms of two adjacent base columns are also connected by the lateral buoys. The upper lateral buoy and the lower lateral buoy are parallel to each other and perpendicular to the base columns.

Furthermore, the base column, the lateral buoy and the lower support rod are all hollow structures, and the inner cavity of the base column, the inner cavity of the lateral buoy located below and the inner cavity of the lower support rod are interconnected to form a sealed cavity, and the sealed cavity is filled with ballast water.

Furthermore, a cable guide hole group is provided at the bottom of each base column, and each cable guide hole group includes at least one cable guide hole.

Furthermore, it also includes a mooring system, which includes a plurality of mooring ropes, one end of which is connected to the base column and the other end of which is connected to an anchor pile on the seabed.

Furthermore, the mooring system also includes a ballast device, and the ballast device is hung on each of the mooring ropes.

Furthermore, the mooring rope is selected to be an anchor chain.

Furthermore, the number of the anchor chains ranges from 3 to 9.

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

The offshore three-floating fully submersible wind turbine foundation structure of the present application includes a floating structure, and the floating structure includes a column, three base columns, a plurality of lateral buoys, a lower support rod and an upper support rod. In the working state, the base column and the column are both vertically arranged, and the three base columns are distributed in a circular array around the column, and two adjacent base columns are connected by the lateral buoys, and the upper part of each base column is connected to the upper part of the column by the upper support rod, and the lower part of each base column is connected to the lower part of the column by the lower support rod; the present application is designed in this way, and the overall structure of the wind turbine foundation structure is distributed in a circular array around the central axis of the column, so that the overall structure is more regular, the force is more stable and uniform, and the integrity is strong. It is located below the water surface in the working state, and the waterline area of the wind turbine foundation structure is small, so that the wave load is greatly reduced, which can reduce the movement of each degree of freedom of the wind turbine under the action of waves, and improve the overall rigidity and stability of the wind power platform.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

FIG1 is a schematic structural diagram of a three-floating fully submersible wind turbine foundation structure disclosed in the present invention;

FIG2 is a top view of the three-floating fully submersible wind turbine foundation disclosed in the present invention;

FIG3 is a diagram showing the arrangement of the mooring system disclosed in the present invention;

FIG. 4 shows the arrangement of the anchor chain disclosed in the present invention.

In the figure: (Description of reference numerals)

101-column; 102-base column; 103-lateral buoy; 104-lower support rod; 105-upper support rod; 106-mooring system; 107-mooring rope; 108-ballast device; 109-fairlead hole.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition and explanation in the subsequent drawings.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the inventive product is usually placed when 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 position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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 elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

Example 1

This embodiment provides an offshore three-floating fully submersible wind turbine foundation structure. The improved wind turbine foundation takes into account the anti-corrosion performance, and reduces the contact area between the foundation and the water surface to a certain extent, reduces the movement of each degree of freedom of the wind turbine under the action of waves, and makes the platform have good anti-tilting stability, heave performance (heave movement) and hydrodynamic performance, as follows:

With reference to Fig. 1 to Fig. 4, this embodiment provides an offshore three-floating fully submersible wind turbine foundation structure, including a floating structure and a mooring system, wherein the floating structure includes a column 101, three foundation columns 102, a plurality of lateral buoys 103, a lower support rod 104, and an upper support rod 105, and the column 101, the three foundation columns 102, the plurality of lateral buoys 103, the lower support rod 104, and the upper support rod 105 can all be made of lightweight materials to ensure their buoyancy in seawater during operation. A preferred embodiment of the present application is that the column 101, the three foundation columns 102, the plurality of lateral buoys 103, the lower support rod 104, and the upper support rod 105 are all set as a hollow structure, and the hollow structure can ensure the buoyancy required in the water.

The length direction of the base column 102 is consistent with that of the column 101, and the three base columns 102 are distributed in a circular array around the column 101. Two adjacent base columns 102 are connected by the lateral buoy 103, and the angle between two adjacent base columns 102 is 120°. The upper and lower ends of the outer side of the base column 102 are fixedly connected and interconnected by the lateral buoy 103 respectively, and the interior of the base column 102 is interconnected with the inner cavity of the lateral buoy 103 below and the lower support rod 104, which is used to adjust the draft, so as to lower the center of gravity of the foundation and improve the overall stability of the floating foundation.

When working in seawater, the top of the column 101 is higher than the top of the base column 102, and the bottom of the column 101 is higher than the bottom of the base column 102. The following content is described in detail based on the state of the wind turbine foundation structure when working in seawater.

The upper part of each base column 102 is connected to the upper part of the column 101 through the upper support rod 105 , and the lower part of each base column 102 is connected to the lower part of the column 101 through the lower support rod 104 .

The angle between the lower support rod 104 and the central axis of the column 101 is 60°; the two ends of the upper support rod 105 are jointly connected to the top of the column 101 and the base column 102, wherein the upper support rod 105 is smaller than the lower support rod 104. When the upper support rod 105 and the column 101 partially sink below the water surface, a part of them is located near the water surface. Corrosion-resistant materials can be used to improve the corrosion resistance of the wind turbine to extend the service life of the wind turbine. At the same time, the surface area of the wind turbine foundation near the water surface is smaller, which can reduce the movement of various degrees of freedom of the platform under the action of wind and waves to a certain extent, ensure the operation effect of the wind turbine, and improve productivity.

The top and bottom of the base column 102 and the bottom of the column 101 are all in a sealed state. At the same time, the upper support rod 105, the lower support rod 104, the lateral buoy 103 and the connection between the base column 102 and the column 101 are fixedly connected to ensure that when the wind turbine foundation encounters a complex wave environment, no seawater will enter the interior of the wind turbine foundation structure, thereby ensuring the stability of the wind turbine base column 102.

The present application is designed in such a way that the overall structure of the wind turbine foundation structure is distributed in a circular array around the central axis of the column 101, so that the overall structure is more regular, the force is more stable and uniform, and the integrity is strong. When it is in working state, it is located below the water surface. The waterline area of the wind turbine foundation structure is small, so that the wave load is greatly reduced, which can reduce the movement of each degree of freedom of the wind turbine under the action of waves and improve the overall rigidity and stability of the wind power platform.

The top and bottom of the base column 102 and the bottom of the column 101 are all in a sealed state, which can prevent water from entering the wind turbine foundation structure under the action of complex wind and waves, thereby causing the wind turbine to become unstable; the wind turbine foundation structure as a whole sinks below the water surface, and the transition section between the upper wind turbine and the foundation structure can adopt corrosion-resistant materials to reduce corrosion from seawater and prevent performance degradation; in addition, the internal cavities of the floating structure are interconnected, so as to facilitate the adjustment of the height of the buoyancy center of the wind turbine foundation through ballast water.

In this embodiment, the specific implementation is as follows: As shown in FIG1 , preferably, the top of the column 101 is higher than the top of the base column 102, and the bottom of the column 101 is higher than the bottom of the base column 102. In this way, when the upper part of each base column 102 is connected to the upper part of the column 101 through the upper support rod 105, each upper support rod 105 is inclined. When the lower part of each base column 102 is connected to the lower part of the column 101 through the lower support rod 104, each lower support rod 104 is inclined.

Preferably, the three upper support rods 105 are distributed in a circular array around the column 101, and the three lower support rods 104 are distributed in a circular array around the column 101. The advantage of the three upper support rods 105 and the three lower support rods 104 being distributed in a circular array is that when the fan foundation structure is in use, each position is subjected to the same force in the water, the force uniformity is improved, and the stability is improved.

The lateral buoy 103 is a hollow cylinder, and the tops of two adjacent base columns 102 are connected by the lateral buoy 103. The number of the lateral buoys 103 can be three, six or nine, etc. The number of the lateral buoys 103 is set according to the three floating bodies, and the number is an integer multiple of three. Taking the number of three, six or nine as an example, there are the following three situations:

1. When the number of the lateral buoys 103 is three, the tops of two adjacent base columns 102 are connected by one lateral buoy 103. The lateral buoy 103 can be set arbitrarily, such as inclined or horizontally, but at the same time, it is necessary to ensure that the three lateral buoys 103 are set in the same way, so that the three lateral buoys 103 are distributed in a circular array around the column 101 after setting, so as to ensure uniform force everywhere and improve stability.

2. When the number of the lateral buoys 103 is six, the tops of two adjacent base columns 102 are connected by two lateral buoys 103, and the two lateral buoys 103 between two adjacent base columns 102 form a group. Each group of lateral buoys 103 can be arranged arbitrarily, such as inclined, cross, parallel or horizontal, but at the same time it is necessary to ensure that the three groups of lateral buoys 103 are arranged in the same manner, so that the three groups of lateral buoys 103 are distributed in a circular array around the column 101 after arrangement to ensure uniform force everywhere and improve stability.

3. When the number of the lateral buoys 103 is nine, the tops of two adjacent base columns 102 are connected by three lateral buoys 103, and the three lateral buoys 103 between two adjacent base columns 102 form a group. Each group of lateral buoys 103 can be arranged arbitrarily, such as inclined, cross, parallel or horizontal, but at the same time it is necessary to ensure that the three groups of lateral buoys 103 are arranged in the same manner, so that the three groups of lateral buoys 103 are distributed in a circular array around the column 101 after arrangement to ensure uniform force everywhere and improve stability.

Combining the above three situations, the second solution is preferably used in this embodiment. As shown in Figure 1, there are six lateral buoys 103 in total. The tops of two adjacent base columns 102 are connected by the lateral buoys 103, and the bottoms of two adjacent base columns 102 are also connected by the lateral buoys 103. The upper lateral buoy 103 and the lower lateral buoy 103 are both horizontally arranged and parallel to each other.

In this embodiment, the inner cavity of the base column 102, the inner cavity of the lateral buoy 103 located below, and the inner cavity of the lower support rod 104 are interconnected to form a sealed cavity, and the sealed cavity is filled with ballast water. In the working state, the three-float fully submerged wind turbine foundation structure is located at a certain depth below the water surface as a whole. The waterline area of the wind turbine foundation structure is small, which greatly reduces the wave load; the ballast water is used to achieve the operating draft. The lateral buoy 103 located below is completely filled with ballast water. The distance from the pressure head of the ballast water of each base column 102 to the top can be adjusted according to a more detailed analysis. The inner cavities of the base column 102, the lower lateral buoy 103 and the lower support rod 104 are interconnected, which can realize the dynamic adjustment of the ballast water, which is beneficial to the balance of the wind turbine foundation.

In a specific example, the center of gravity of the offshore three-floating fully submersible foundation structure is -13.877m, and the center of buoyancy is -14.541m. The diameter of the base column 102 is 12m, the diameter of the column 101 is 6.5m, the diameter of the lateral buoy 103 and the lower support rod 104 is 4m, and the diameter of the upper support rod 105 is 2m. The mass of the wind turbine foundation structure is 2392.21t, and the displacement is 9649.87t.

It should be noted that the specific parameters of the offshore three-floating fully submersible foundation structure can be analyzed and adjusted in detail according to the conditions in different sea areas, and the appropriate mooring system layout can be selected according to needs, without having to stick to the specific dimensional data in this example.

In addition, considering that the wind turbine foundation structure needs anti-corrosion protection when used in seawater, two situations need to be considered when selecting materials for the wind turbine foundation structure: (1) When the column 101 is completely submerged in water, ordinary steel is used, and corrosion-resistant materials can be used for the transition section between the upper wind turbine and the wind turbine foundation structure. (2) When the column 101 and the upper support rod 105 are partially submerged in water, both are made of corrosion-resistant materials. At the same time, corrosion-resistant materials are used for structures near the water surface, taking into account the anti-corrosion needs of wind turbines in complex marine environments, and the wind resistance and stability of the fully submersible wind power platform are further improved through the mooring system 106. It should be noted that corrosion-resistant materials can be selected from weathering steel, fiber reinforced composite materials (FRP) and other anti-corrosion materials, and the corrosion-resistant materials that can be selected are not limited to the two materials mentioned above. Other applicable corrosion-resistant materials are also within the scope of protection of this application.

In this embodiment, as shown in FIG3 , the mooring system 106 includes a plurality of mooring ropes 107, one end of the mooring ropes 107 is connected to the base column 102, and the other end is connected to the anchor pile on the seabed, and the mooring system 106 also includes a ballast device 108, and each of the mooring ropes 107 is hung with the ballast device 108. The ballast device 108 is preferably a ballast block, and the mooring ropes 107 are preferably anchor chains, and the number of anchor chains ranges from 3 to 9. The mooring system 106 facilitates fixing the entire foundation structure (or wind power platform) underwater, reduces wind and wave loads, and improves the overall stability of the three-floating body fully submersible foundation structure.

The mooring system 106 is achieved by providing a group of fairlead holes at the bottom of each base column 102, including at least one fairlead hole 109, preferably a group of fairlead holes includes one to three fairlead holes 109, and one end of the anchor chain is connected to the corresponding fairlead hole 109, and the other end is fixed to the seabed, and a ballast block with a certain mass is provided at the lower part of the anchor chain; preferably, a group of fairlead holes includes three fairlead holes 109 and corresponds to a total of nine anchor chains, and at the same time, the nine anchor chains are arranged in a nine-anchor symmetrical manner, as shown in Figure 4, three anchor chains are connected to the corresponding fairlead holes 109 at the bottom of the base column 102, and the angle between any two adjacent anchor chains is 40°, providing restoring force for the wind turbine foundation structure from all directions, thereby ensuring the stability of the wind turbine.

The three-float fully submersible foundation floating structure is arranged in an equilateral triangle shape, has good stability, and has a simple structural layout. At the same time, multiple anchor chains in the mooring system are arranged in a circumferential direction around the column 101, so that the foundation has good vertical and horizontal stiffness, which improves the connection strength between the mooring system and the basic floating structure, thereby further improving the overall stability of the three-float fully submersible foundation.

In the working state, the three-float fully submersible wind turbine foundation is located as a whole at a certain depth below the water surface. The waterline area of the wind turbine foundation is small, which greatly reduces the wave load; ballast water is used to achieve operational draft, and the lower lateral buoy 103 is completely filled with ballast water. The distance from the pressure head of the ballast water of each base column 102 to the top can be adjusted according to a more detailed analysis. The base column 102, the lower lateral buoy 103 and the lower support rod 104 are interconnected, which can realize dynamic adjustment of the ballast water, which is beneficial to the balance of the wind turbine foundation.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and to form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present invention and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (6)

1. An offshore three-floating fully submersible wind turbine foundation structure, comprising a floating structure, characterized in that the floating structure comprises a column (101), three foundation columns (102), a plurality of lateral buoys (103), a lower support rod (104) and an upper support rod (105); The length directions of the base column (102) and the column (101) are consistent, and three base columns (102) are distributed in a circular array around the column (101), and two adjacent base columns (102) are connected by the lateral buoy (103); The upper part of each base column (102) is connected to the upper part of the upright column (101) via the upper support rod (105), and the lower part of each base column (102) is connected to the lower part of the upright column (101) via the lower support rod (104); When in working state, the top of the upright column (101) is higher than the top of the base column (102), and the bottom of the upright column (101) is higher than the bottom of the base column (102); The three upper support rods (105) are distributed in a circular array around the column (101), and the three lower support rods (104) are distributed in a circular array around the column (101); There are six lateral buoys (103) in total. The tops of two adjacent base columns (102) are connected by the lateral buoys (103), and the bottoms of two adjacent base columns (102) are also connected by the lateral buoys (103). The upper lateral buoy (103) and the lower lateral buoy (103) are parallel to each other and perpendicular to the base columns (102). The base column (102), the lateral buoy (103), the upper support rod (105) and the lower support rod (104) are all made of lightweight materials, and the base column (102), the lateral buoy (103) and the lower support rod (104) are all hollow structures. The inner cavity of the base column (102), the inner cavity of the lateral buoy (103) located below, and the inner cavity of the lower support rod (104) are interconnected to form a sealed cavity, and the sealed cavity is filled with ballast water. 2. The offshore three-floating fully submersible wind turbine foundation structure according to claim 1 is characterized in that a cable guide hole group is provided at the bottom of each of the base columns (102), and each group of the cable guide hole groups includes at least one cable guide hole (109). 3. The offshore three-floating fully submersible wind turbine foundation structure according to any one of claims 1-2 is characterized in that it also includes a mooring system (106), the mooring system (106) includes a plurality of mooring ropes (107), one end of the mooring rope (107) is connected to the base column (102), and the other end is connected to an anchor pile on the seabed. 4. The offshore three-floating fully submersible wind turbine foundation structure according to claim 3 is characterized in that the mooring system (106) also includes a ballast device (108), and the ballast device (108) is hung on each of the mooring ropes (107). 5. The offshore three-floating fully submersible wind turbine foundation structure according to claim 4, characterized in that the mooring rope (107) is selected as an anchor chain. 6. The offshore three-floating fully submersible wind turbine foundation structure according to claim 5, characterized in that the number of the anchor chains ranges from 3 to 9.