I-shaped semi-submersible floating type offshore wind turbine system

Abstract

The utility model relates to the technical field of offshore wind turbines, and discloses an I-shaped semi-submersible floating type offshore wind turbine system. The offshore wind turbine system comprises a floating type wind turbine foundation, a tower drum, a wind turbine generator and an anchoring system, the tower drum is fixed on the floating type wind turbine foundation, the wind turbine generator is installed on the upper portion of the tower drum, and the anchoring system is connected with the floating type wind turbine foundation; the floating type draught fan foundation comprises I-shaped buoyancy tanks, a center stand column, at least three outer side stand columns, an arch-shaped supporting structure and a connecting round pipe, the center stand column is arranged at one intersection point of the I-shaped buoyancy tanks, and the tower drum is fixedly connected with the center stand column. The at least three outer side stand columns are arranged at the end points of the I-shaped floating box correspondingly, and the outer side stand columns are away from the arch-shaped supporting structure to form free ends. The I-shaped buoyancy tank comprises a first section of buoyancy tank, a second section of buoyancy tank and a middle buoyancy tank, the arched supporting structures are fixedly connected between the first / second section of buoyancy tank and the central stand column and between the middle buoyancy tank and the central stand column, and the arched supporting structures are arranged in an upward arched mode.

Description

Technical Field

[0001] The utility model relates to the technical field of offshore wind turbines, in particular to an I-shaped semi-submersible floating offshore wind turbine system. Background Art

[0002] As offshore wind power gradually develops into the deep sea, deep sea wind farms usually adopt the floating wind turbine foundation solution, fixing the wind turbine foundation to the seabed through an anchoring system. It has low cost and is widely applicable to various geological conditions.

[0003] Floating wind turbine foundations are mainly divided into four basic types: Spar, Semi, TLP and Barge. Among them, "Semi" is also called semi-submersible wind turbine foundation, which has the characteristics of wide applicable water depth range, excellent comprehensive performance, high technical maturity, etc. The existing semi-submersible floating wind turbine foundation design is in the form of an equilateral triangle pontoon + three columns or four columns. When the wind turbine is erected on the central column of the triangle, the central column has little effect on the stability of the floating body and the hydrostatic recovery stiffness. When the wind turbine is erected on the corner column of the triangle, this corner column has the dual functions of adjusting the hydrodynamic performance and supporting the wind turbine, which is not conducive to the optimization design of the overall system, resulting in increased difficulty in the top node design of the column, the berthing design, the mooring design and the dynamic submarine cable design.

[0004] In addition, existing semi-submersible floating wind turbine foundations usually use box beams or circular tube support structures to connect the columns. The huge wind turbine load is further transmitted to the columns through these connection structures, which places higher requirements on the bearing capacity of the columns.

[0005] In summary, the existing semi-submersible floating wind turbine foundation has insufficient stability reserve in extreme marine environments, high hydrodynamic loads, large motion deflection angles, and weak structural bearing capacity, making it difficult to achieve the goal of taking into account motion performance, support capacity, and overall system collaborative design. Therefore, it is urgent to propose a floating wind turbine foundation concept with better force transmission, low cost, high stability, and easy collaborative design. Utility Model Content

[0006] The technical problem to be solved by the utility model is that the existing semi-submersible floating wind turbine foundation has insufficient stability reserve in extreme marine environment, high hydrodynamic load, large movement deflection angle, weak structural bearing capacity, and it is difficult to achieve the purpose of taking into account movement performance, support capacity and facilitating coordinated design of the overall system.

[0007] In order to solve the above technical problems, the utility model provides an I-shaped semi-submersible floating offshore wind turbine system:

[0008] The I-shaped semi-submersible floating offshore wind turbine system comprises a floating wind turbine foundation, a tower, a wind turbine generator set and an anchoring system, wherein the tower is fixedly arranged on the floating wind turbine foundation, the wind turbine generator set is installed on the upper part of the tower, and the anchoring system is connected to the floating wind turbine foundation;

[0009] The floating wind turbine foundation comprises an I-shaped pontoon, a central column, at least three outer columns, an arched support structure and a connecting circular tube, wherein the central column is arranged at an intersection of the I-shaped pontoon, and the tower is fixedly connected to the central column; at least three outer columns are respectively arranged at the end points of the I-shaped pontoon, and the outer columns are away from the arched support structure to form free ends;

[0010] The I-shaped pontoon includes a first section pontoon and a second section pontoon arranged in parallel and spaced apart, and an intermediate pontoon fixedly connected between the first section pontoon and the second section pontoon, the arched support structure is fixedly connected between the first section pontoon / the second section pontoon and the central column, and between the intermediate pontoon and the central column, and the arched support structure is arranged in an arched manner relative to the upper side of the I-shaped pontoon; the connecting circular tubes are respectively arranged on the left and right sides of the I-shaped pontoon.

[0011] Further, the length of the first section pontoon is greater than that of the second section pontoon, and the central column is arranged at the intersection of the first section pontoon and the middle pontoon, or the central column is arranged at the intersection of the second section pontoon and the middle pontoon.

[0012] Furthermore, the arch support structure includes a horizontal support section and an oblique support section, the horizontal support section is arranged parallel to the upper side of the I-shaped pontoon, the horizontal support section is fixedly connected to the top of the central column, and the oblique support section is fixedly connected between the horizontal support section and the upper side of the I-shaped pontoon. When the central column is arranged at the intersection of the second section pontoon and the middle pontoon, the oblique support section on the second section pontoon can also be eliminated, and the horizontal support section can be directly connected to the outer column.

[0013] Furthermore, the central column includes a central top column and a central lower column, the diameter of the central lower column is smaller than the diameter of the central top column, the upper end of the central lower column is inserted into the interior of the central top column, and the central lower column is inserted and installed inside an intersection of the I-shaped pontoon.

[0014] Furthermore, the outer column includes an outer upper column and an outer bottom column, the diameter of the outer bottom column is larger than the diameter of the outer upper column, the outer bottom column is fixedly connected to the I-shaped pontoon, and the outer upper column has an extended portion extending upward and protruding above the water surface.

[0015] Furthermore, the outer upper column is a single column structure, the outer upper column is extended in a vertical direction or in an outwardly inclined direction, and the outer upper column is a variable diameter frustum structure that is thick at the top and thin at the bottom.

[0016] Furthermore, the outer upper columns are a multi-column structure combined in parallel, the outer upper columns are extended in a vertical direction or in an outwardly inclined direction, and the number of upper multi-columns of the outer upper columns is greater than the number of lower multi-columns of the outer upper columns.

[0017] Furthermore, the two connecting circular tubes are symmetrical about the middle pontoon of the I-shaped pontoon, and the connecting circular tubes are inserted into the inside of the first section pontoon and the second section pontoon, or the connecting circular tubes are inserted into the inside of the outer bottom column.

[0018] Furthermore, the I-shaped pontoon is a flat pontoon whose width is greater than its height. The I-shaped pontoon is made of a concrete structure, a steel structure or a steel-concrete structure. The interior of the I-shaped pontoon, the interior of the central column, and the interior of the outer columns are also provided with variable ballast tanks, empty tanks or equipment compartments.

[0019] Furthermore, a heave plate or a fixed ballast body is further provided on the bottom surface of the I-shaped pontoon, and the shape of the heave plate or the fixed ballast body is an isosceles trapezoid extending along the outer contour of the I-shaped pontoon;

[0020] The heave plate is a sheet structure, or the fixed ballast body is a flat shell structure filled with iron ore, concrete, stones, sand or ore materials, or the fixed ballast body is a flat solid structure with a density greater than that of the variable ballast tank.

[0021] Compared with the prior art, the utility model discloses an I-shaped semi-submersible floating offshore wind turbine system, which has the following beneficial effects: the I-shaped semi-submersible floating offshore wind turbine system adopts the design form of a floating wind turbine foundation, a tower, a wind turbine unit and an anchoring system, wherein the tower is fixedly arranged on the floating wind turbine foundation, the wind turbine unit is installed on the upper part of the tower, and the anchoring system is connected to the floating wind turbine foundation, wherein the floating wind turbine foundation includes an I-shaped buoy, a central column, at least three outer columns, an arched support structure and a connecting circular pipe.

[0022] The I-shaped pontoon, the central column, at least three outer columns, the arch support structure and the connecting circular tube form a basic structure with simple spatial geometry, clear force transmission and strong bearing capacity. The I-shaped pontoon is mainly used to provide huge buoyancy. Under large-capacity wind turbines and extreme marine environmental conditions, the I-shaped pontoon can reduce the amount of steel and reduce wave forces. At the same time, a variable ballast tank can be set inside the I-shaped pontoon, and by filling the variable ballast tank with water or a higher density ballast, a huge gravity effect is generated and the center of gravity is lowered.

[0023] This floating wind turbine foundation is different from the traditional triangular semi-submersible wind turbine foundation. A central column for supporting the wind turbine set is arranged at the intersection of the I-shaped pontoon, and at least three outer columns are arranged at the outer end points of the I-shaped pontoon, so that the central column is far away from the center of the still water surface (also called the "floating center") and separated from the outer columns. This can not only improve the stability of the floating wind turbine foundation, but also increase and more flexibly adjust the still water recovery stiffness of the floating body in all directions by adjusting the side length of the I-shaped side, the diameter of the central column and the diameter of the outer columns, optimize the deflection free motion period, and reduce the maximum deflection angle of the floating body.

[0024] Moreover, the outer columns are far away from the arched support structure to form free ends, and will not bear the huge wind turbine load transmitted from the upper wind turbine and tower, which facilitates the lightweight design of the columns. The outer upper columns can be designed as a single-column structure with an outward-inclined variable-diameter cone or an outward-inclined multi-column structure in parallel combination, which can further increase the hydrostatic recovery stiffness, improve the stability of the floating body, and improve the motion performance. The central column and the outer columns are separated from each other and have relatively independent structural functions, which facilitates the coordinated design of mooring, dynamic cables, and berthing systems. At the same time, the location of the central column is more conducive to the installation of wind turbines in docks or docks, reducing the requirements for ship equipment resources.

[0025] By designing an arched support structure with three sides distributed on the I-shaped pontoon, the central column and the I-shaped pontoon are integrated to form a structural system with strong support capacity. The arched support structure is more conducive to the transmission of the upper wind turbine load, reducing stress concentration, improving the bearing capacity, and at the same time improving the fatigue resistance of the support structure. The connecting round pipes are respectively arranged on the left and right sides of the I-shaped pontoon, which is conducive to improving the bearing capacity of the I-shaped pontoon under the splitting force between the outer columns.

[0026] In addition, a fixed ballast extending outward can be arranged along the bottom surface of the I-shaped pontoon and the outer column. The fixed ballast is a flat high-density structure that can play the role of ballast weight increase, so that the center of gravity of the entire floating wind turbine foundation is effectively lowered. Alternatively, the heave plate structure of the reinforced thin plate can significantly increase the additional mass and motion damping of the floating body. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1It is a structural schematic diagram of an I-shaped semi-submersible floating offshore wind turbine system in an embodiment of the utility model;

[0028] Figure 2 It is a three-dimensional schematic diagram of an I-shaped semi-submersible floating offshore wind turbine system in an embodiment of the utility model;

[0029] Figure 3 It is a front view schematic diagram of an I-shaped semi-submersible floating offshore wind turbine system in an embodiment of the utility model;

[0030] Figure 4 It is a top view schematic diagram of an I-shaped semi-submersible floating offshore wind turbine system in an embodiment of the utility model;

[0031] Figure 5 It is a three-dimensional schematic diagram of a floating wind turbine foundation in an embodiment of the utility model;

[0032] Figure 6 It is a top view schematic diagram of a heave plate or a fixed pressure body at the bottom of a floating wind turbine foundation in an embodiment of the utility model;

[0033] Figure 7 It is a top view schematic diagram of a T-shaped buoyancy structure on the upper part of a floating wind turbine foundation in an embodiment of the utility model;

[0034] Figure 8 It is a top view schematic diagram of another embodiment of the utility model when the outer upper column is a variable diameter frustum structure with a thick upper part and a thin lower part;

[0035] Fig. 9 It is a top view schematic diagram of a case where the outer upper column in other embodiments of the utility model is a multi-column structure combined in parallel;

[0036] Fig.10 It is a three-dimensional schematic diagram of an I-shaped semi-submersible floating offshore wind turbine system in other embodiments of the utility model;

[0037] Fig.11 for Fig.10 Schematic diagram of the mid-floating wind turbine foundation;

[0038] In the figure: 1-floating wind turbine foundation, 10-I-shaped pontoon, 100-middle pontoon, 101-first section pontoon, 102-second section pontoon, 11-center column, 110-center top column, 111-center lower column, 12-outer column, 120-outer upper column, 121-outer bottom column, 122-fairlead hole, 13-arch support structure, 130-horizontal support section, 131-oblique support section, 14-connecting circular pipe, 15-heave plate or fixed ballast body, 1 50-the inclined side section of the lifting plate or the fixed ballast body, 151-the long side section of the lifting plate or the fixed ballast body, 152-the short side section of the lifting plate or the fixed ballast body, 16-T-shaped buoyancy structure, 2-tower, 3-wind turbine, 30-nacelle, 31-blade, 32-hub, 4-anchoring system, 40-mooring cable, 41-anchor, 120A-variable diameter frustum structure, 121A-outer bottom column, 120B-parallel combination of multi-column structure, 121B-outer bottom column. DETAILED DESCRIPTION

[0039] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like used in the present invention to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0042] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between 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.

[0043] like Figures 1 to 7 As shown, an I-shaped semi-submersible floating offshore wind turbine system of an embodiment of the utility model includes a floating wind turbine foundation 1, a tower 2, a wind turbine set 3 and an anchoring system 4, the tower 2 is fixedly arranged on the floating wind turbine foundation 1, the wind turbine set 3 is installed on the upper part of the tower 2, and the anchoring system 4 is connected to the floating wind turbine foundation 1; the floating wind turbine foundation 1 includes an I-shaped pontoon 10, a central column 11, at least three outer columns 12, an arched support structure 13 and a connecting circular tube 14, the central column 11 is arranged at an intersection of the I-shaped pontoon 10, the tower 2 is fixedly connected to the central column 11, and the connecting circular tube 14 is respectively arranged on the left and right sides of the I-shaped pontoon 10.

[0044] At least three outer columns 12 are respectively arranged at the end points of the I-shaped pontoon 10, and at least three outer columns 12 form free ends away from the arch support structure 13; the I-shaped pontoon 10 includes a first section pontoon 101 and a second section pontoon 102 arranged in parallel and spaced apart, and an intermediate pontoon 100 fixedly connected between the first section pontoon 101 and the second section pontoon 102, the arch support structure 13 is fixedly connected between the first section pontoon 101 / the second section pontoon 102 and the central column 11, and between the intermediate pontoon 100 and the central column 11, and the arch support structure 13 is arched relative to the upper side of the I-shaped pontoon 10.

[0045] The I-shaped pontoon 10, the central column 11, at least three outer columns 12, the arched support structure 13 and the connecting circular tube 14 of the floating wind turbine foundation 1 form a basic structure with simple spatial geometric configuration, clear force transmission and strong bearing capacity. The I-shaped pontoon 10 is mainly used to provide huge buoyancy. At the same time, a variable ballast tank can be arranged inside the I-shaped pontoon 10. By filling the variable ballast tank with water or a ballast with a higher density, a huge gravity effect is generated and the center of gravity is lowered.

[0046] The floating wind turbine foundation 1 is different from the traditional triangular semi-submersible wind turbine foundation. A central column 11 for supporting the wind turbine set 3 is arranged at the intersection of the I-shaped pontoon 10, and at least three outer columns 12 are arranged at the outer end points of the I-shaped pontoon 10, so that the central column 11 is far away from the center of the still water surface (also called the "floating center") and is separated from the outer columns 12. This can not only improve the stability of the floating wind turbine foundation 1, but also increase and more flexibly adjust the still water recovery stiffness of the floating body in all directions by adjusting the side length of the I-shaped side, the diameter of the central column 11 and the diameter of the outer columns 12, optimize the deflection free movement period, and reduce the maximum deflection angle of the floating body.

[0047] Moreover, the outer column 12 is far away from the arch support structure 13 to form a free end, and will not bear the huge wind turbine load transmitted by the upper wind turbine and the tower 2, which is convenient for the lightweight design of the column. The outer upper column 120 can be designed as a single-column structure of an outwardly inclined variable-diameter cone or an outwardly inclined parallel combination of multiple columns, which can further increase the hydrostatic recovery stiffness, improve the stability of the floating body, and improve the motion performance. The central column 11 and the outer column 12 are separated from each other, and the central column 11 and the outer column 12 have relatively independent structural functions, which is convenient for the coordinated design of mooring, dynamic cables, and berthing systems. At the same time, the position of the central column 11 is more conducive to the installation of wind turbines 3 in the dock or dock, reducing the requirements for ship machinery and equipment resources.

[0048] In this embodiment, the length of the first section pontoon 101 is greater than the length of the second section pontoon 102, and the central column 11 is arranged at the intersection of the first section pontoon 101 and the middle pontoon 100. Specifically, the arch support structure 13 includes a horizontal support section 130 and an oblique support section 131. The horizontal support section 130 is arranged parallel to the upper side of the I-shaped pontoon 10. The horizontal support section 130 is fixedly connected to the top of the central column 11, and the oblique support section 131 is fixedly connected between the horizontal support section 130 and the upper side of the I-shaped pontoon 10. Among them, the arch support structure 13 can adopt a box beam or a circular tube structure, and the angle between the oblique support section 131 and the horizontal plane is usually 30° to 60°. The arch support structure 13 is a three-sided arch design, which is more conducive to the transmission of the upper wind turbine load, reduces stress concentration, improves the bearing capacity, and can also improve the fatigue resistance of the support structure.

[0049] The central column 11 includes a central top column 110 and a central lower column 111. The diameter of the central lower column 111 is smaller than the diameter of the central top column 110. The upper end of the central lower column 111 is plugged into the interior of the central top column 110. The central lower column 111 is plugged and installed inside an intersection of the I-shaped pontoon 10. The outer column 12 includes an outer upper column 120 and an outer bottom column 121. The diameter of the outer bottom column 121 is larger than the diameter of the outer upper column 120. The outer bottom column 121 is fixedly connected to the I-shaped pontoon 10. The outer upper column 120 has a protruding portion extending upward and protruding above the water surface.

[0050] As a further preferred solution, in order to simplify the structural design, the outer bottom column 121 can be eliminated from the outer column 12 on the second section pontoon 102, so that the outer upper column 120 is directly connected to the second section pontoon 102. Moreover, the outer upper column 120 on the first section pontoon 101 and the outer upper column 120 of the second section pontoon 102 can be designed to have different diameters. Both the central column 11 and the outer column 12 can adopt a cylindrical or multi-prism structure.

[0051] In this embodiment, the outer upper column 120 is a single column structure, and the outer upper column 120 is arranged to extend in the vertical direction. In order to meet different usage conditions, in other embodiments, such as Figure 8 As shown, the outer bottom column 121A remains unchanged on the basis of the above embodiment, and the outer upper column can be extended and arranged in an outwardly inclined direction, and the outer upper column is a variable diameter frustum structure 120A that is thick at the top and thin at the bottom. Fig. 9 As shown, the outer bottom column 121B remains unchanged on the basis of the above embodiment, and the outer upper column is a multi-column structure 120B combined in parallel. The outer upper column is extended in an outwardly inclined direction or in a vertical direction, and the number of upper multi-columns of the outer upper column is greater than the number of lower multi-columns of the outer upper column.

[0052] The two connecting circular tubes 14 are symmetrical about the middle pontoon 100 of the I-shaped pontoon 10, and the connecting circular tubes 14 are inserted into the inside of the first section pontoon 101 and the second section pontoon 102, or the connecting circular tubes 14 are inserted into the inside of the outer bottom column 121. The diameter D5 of the connecting circular tube 14 is 3 meters, and the second section pontoon 102 is rigidly connected to the outer bottom column 121 on the first section pontoon 101 or the first section pontoon 101 through the connecting circular tube 14, which is beneficial to improve the bearing capacity of the floating wind turbine foundation 1 under the action of the splitting force between the outer columns 12 under the action of extreme wave loads.

[0053] The I-shaped pontoon 10 is a flat pontoon whose width is greater than its height. The I-shaped pontoon 10 is made of a concrete structure, a steel structure or a steel-concrete structure. The inside of the I-shaped pontoon 10, the inside of the central column 11, and the inside of the outer column 12 are also provided with a variable ballast tank, an empty tank or an equipment cabin. The bottom surface of the I-shaped pontoon 10 is also provided with a heave plate or a fixed ballast body 15. The shape of the heave plate or the fixed ballast body 15 is an isosceles trapezoid extending along the outer contour of the I-shaped pontoon 10. The heave plate or the fixed ballast body 15 includes two oblique side segments 150 of the heave plate or the fixed ballast body, a long side segment 151 of the heave plate or the fixed ballast body, and a short side segment 152 of the heave plate or the fixed ballast body. Each side segment is sequentially arranged along the outer contour of the I-shaped pontoon 10 to form an isosceles trapezoid.

[0054] Specifically, the heave plate is a large-area thin-sheet structure, which can significantly increase the damping of the heave and deflection motion of the floating wind turbine foundation 1. Alternatively, the fixed ballast body is a flat shell structure, the interior of which is filled with iron ore, concrete, stones, sand or ore materials, and the fixed ballast body is fixed to the surrounding area outside the bottom surface of the floating wind turbine foundation 1. Alternatively, the fixed ballast body is a flat solid structure, and its density is greater than that of the variable ballast tank. The center of gravity of the floating wind turbine foundation 1 can be further lowered by the fixed ballast body, which can also play a role in increasing motion damping; in large-capacity wind turbines and extreme marine environment conditions, the I-shaped pontoon 10 can reduce the amount of steel used and reduce wave forces.

[0055] In addition, a T-shaped buoyancy structure 16 may be arranged underwater at a position close to the still water surface on the upper side of the I-shaped buoyancy tank 10. Figure 7 As shown, the T-shaped buoyancy structure 16 is embedded between the diagonal support section 131 of the arch support structure 13 and the central lower column 111. Its density is less than that of water and it has high strength characteristics. It can further increase the buoyancy of the floating wind turbine foundation 1, raise the center of buoyancy, improve the stability of the overall structure, and improve the movement performance.

[0056] like Figure 3 , Figure 4As shown, in terms of the specific dimensions of the floating wind turbine foundation 1, the outer edge width (profile width) W1 between the two outer bottom columns 121 on the first section pontoon 101 is 115.6 meters, the center distance W2 between the two outer bottom columns 121 on the first section pontoon 101 is 97.6 meters, the center distance W3 between the central lower column 111 and the outer bottom column 121 on the second section pontoon 102 is 77.5 meters, and the cross-sectional width W4 of the I-shaped pontoon 10 is 12 meters. The arched support structure 13 adopts a square cross-sectional box beam with a cross-sectional width W5 of 4 meters, and the center distance W6 between the two outer upper columns 120 on the second section pontoon 102 is 30 meters. As a further preferred embodiment, there are four outer upper columns 120, that is, one outer column 12 is provided at each outer end point of the I-shaped pontoon 10, the diameter D3 of the outer upper column 120 on the second section pontoon 102 is 9 meters, the diameter D4 of the outer bottom column 121 on the first section pontoon 101 is 18 meters, the diameter D6 of the center top column 110 is 11 meters, and the diameter D7 of the center lower column 111 is 6 meters.

[0057] It should be noted that the wind turbine 3 includes a nacelle 30, blades 31 and a hub 32. The unit capacity of the wind turbine 3 can reach 16MW or more, and the impeller diameter D1 can reach more than 252 meters. In order to ensure stable support of the wind turbine 3, the outer diameter D2 of the mooring system 4 is 900 meters. According to the wind turbine 3 of the floating offshore wind turbine system, the height H1 from the bottom end of the I-shaped pontoon 10 to the center of the hub 32 is 148 meters, the height H2 from the bottom end of the I-shaped pontoon 10 to the highest point of the blade 31 is 274 meters, the height H3 from the bottom end of the floating wind turbine foundation 1 to the top of the central column 11 (i.e., the height of the floating wind turbine foundation 1) is 33.5 meters, the height H4 from the bottom end of the floating wind turbine foundation 1 to the top of the outer column 12 is 32 meters, and the draft H5 of the floating wind turbine foundation 1 is 15 meters.

[0058] The modules of the floating wind turbine foundation 1 are prefabricated as a whole, and then the tower 2 and the wind turbine 3 are assembled, transported to the target sea area by wet support, and the on-site mooring system 4 is installed in place, so that the offshore construction is simpler and saves time and effort. In addition, the mooring system 4 includes at least three mooring cables 40, the bottom ends of the mooring cables 40 are connected to anchors 41 and fixed to the seabed, and the outer upper column 120 is provided with a cable guide hole 122, and the top ends of the mooring cables 40 are connected to the cable guide hole 122. Specifically, the mooring system 4 includes six mooring cables 40 (not shown in the figure), each outer upper column 120 on the first section pontoon 101 is provided with two fairlead holes 122, and each outer upper column 120 on the second section pontoon 102 is provided with a fairlead hole 122, the number of fairlead holes 122 matches the number of mooring cables 40 and anchors 41, and the six mooring cables 40 are arranged extending in the radial direction. The mooring system 4 can be used to perform catenary mooring, semi-tensioned mooring or tensioned mooring on the floating wind turbine foundation 1. In addition, the mooring cables 40 can be made of materials such as anchor chains, steel cables, and high molecular polyethylene cables, and are designed in combination according to the water depth, environmental conditions, and the movement of the floating wind turbine foundation 1.

[0059] In other embodiments, according to the different positions of the wind turbine generator set 3, the central column 11 can also be arranged at the intersection of the second section pontoon 102 of the I-shaped pontoon 10 and the middle pontoon 100. Fig.10 , Fig.11 As shown, since the center distance W6 between the two outer upper columns 120 on the second section pontoon 102 is small, the diagonal support section 131 on the second section pontoon 102 can be eliminated, and the center top column 110 and the outer upper column 120 can be directly connected through the horizontal support section 130.

[0060] 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 principle of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. An I-shaped semi-submersible floating offshore wind turbine system, characterized in that: It comprises a floating wind turbine foundation, a tower, a wind turbine generator set and an anchoring system, wherein the tower is fixedly arranged on the floating wind turbine foundation, the wind turbine generator set is installed on the upper part of the tower, and the anchoring system is connected to the floating wind turbine foundation; The floating wind turbine foundation comprises an I-shaped pontoon, a central column, at least three outer columns, an arched support structure and a connecting circular tube, wherein the central column is arranged at an intersection of the I-shaped pontoon, and the tower is fixedly connected to the central column; at least three outer columns are respectively arranged at the end points of the I-shaped pontoon, and the outer columns are away from the arched support structure to form free ends; The I-shaped pontoon includes a first section pontoon and a second section pontoon arranged in parallel and spaced apart, and an intermediate pontoon fixedly connected between the first section pontoon and the second section pontoon, the arched support structure is fixedly connected between the first section pontoon / the second section pontoon and the central column, and between the intermediate pontoon and the central column, and the arched support structure is arranged in an arched manner relative to the upper side of the I-shaped pontoon; the connecting circular tubes are respectively arranged on the left and right sides of the I-shaped pontoon.

2. The I-shaped semi-submersible floating offshore wind turbine system according to claim 1 is characterized in that: The length of the first section pontoon is greater than that of the second section pontoon, and the central column is arranged at the intersection of the first section pontoon and the middle pontoon, or the central column is arranged at the intersection of the second section pontoon and the middle pontoon.

3. The I-shaped semi-submersible floating offshore wind turbine system according to claim 1 is characterized in that: The arch support structure includes a horizontal support section and an oblique support section. The horizontal support section is arranged parallel to the upper side of the I-shaped pontoon, the horizontal support section is fixedly connected to the top of the central column, and the oblique support section is fixedly connected between the horizontal support section and the upper side of the I-shaped pontoon.

4. The I-shaped semi-submersible floating offshore wind turbine system according to claim 1 is characterized in that: The central column includes a central top column and a central lower column. The diameter of the central lower column is smaller than the diameter of the central top column. The upper end of the central lower column is inserted into the interior of the central top column. The central lower column is inserted and installed inside an intersection of the I-shaped pontoon.

5. The I-shaped semi-submersible floating offshore wind turbine system according to claim 1 is characterized in that: The outer column includes an outer upper column and an outer bottom column. The diameter of the outer bottom column is greater than the diameter of the outer upper column. The outer bottom column is fixedly connected to the I-shaped pontoon. The outer upper column has a protruding portion extending upward and protruding above the water surface.

6. The I-shaped semi-submersible floating offshore wind turbine system according to claim 5 is characterized in that: The outer upper column is a single column structure, the outer upper column is extended in a vertical direction or in an outwardly inclined direction, and the outer upper column is a variable diameter frustum structure that is thick at the top and thin at the bottom.

7. The I-shaped semi-submersible floating offshore wind turbine system according to claim 5 is characterized in that: The outer upper columns are a multi-column structure combined in parallel. The outer upper columns are extended in a vertical direction or in an outwardly inclined direction. The number of upper multi-columns of the outer upper columns is greater than the number of lower multi-columns of the outer upper columns.

8. The I-shaped semi-submersible floating offshore wind turbine system according to claim 5 is characterized in that: The two connecting circular tubes are symmetrical about the middle pontoon of the I-shaped pontoon, and the connecting circular tubes are inserted into the inside of the first section pontoon and the second section pontoon, or the connecting circular tubes are inserted into the inside of the outer bottom column.

9. The I-shaped semi-submersible floating offshore wind turbine system according to claim 1 is characterized in that: The I-shaped pontoon is a flat pontoon whose width is greater than its height. The I-shaped pontoon is made of concrete structure, steel structure or steel-concrete structure. The interior of the I-shaped pontoon, the interior of the central column and the interior of the outer columns are also provided with variable ballast tanks, empty tanks or equipment cabins.

10. The I-shaped semi-submersible floating offshore wind turbine system according to claim 9 is characterized in that: The bottom surface of the I-shaped pontoon is also provided with a heave plate or a fixed ballast body, and the shape of the heave plate or the fixed ballast body is an isosceles trapezoid extending along the outer contour of the I-shaped pontoon; The heave plate is a sheet structure, or the fixed ballast body is a flat shell structure filled with iron ore, concrete, stones, sand or ore materials, or the fixed ballast body is a flat solid structure with a density greater than that of the variable ballast tank.

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