Novel five-stand-column semi-submersible wind power foundation and mooring system thereof

Abstract

The invention provides a novel five-stand-column semi-submersible type wind power foundation and a mooring system thereof. The novel five-stand-column semi-submersible type wind power foundation comprises an X-shaped buoyancy tank, side stand columns are arranged at the four ends of the X-shaped buoyancy tank, a center stand column is arranged in the center of the X-shaped buoyancy tank, and the four side stand columns are distributed in a central symmetry mode relative to the center stand column; a tower drum is arranged on the center stand column, and a wind turbine generator set is arranged at the top end of the tower drum and converts wind energy into electric energy. An outer platform is further arranged on the peripheral face of the joint of the center stand column and the tower drum. The number of side stand columns providing stability in the prior art is increased from three to four, and the waterplane inertia moment is increased by nearly 50% under the condition that the waterplane area is not changed; the stress of the structure is completely transferred to the X-shaped floating box, so that the gravity center of the structure is lowered; meanwhile, communication of the side stand columns and the middle stand columns is achieved through the design that the deck channel and the outer platform are staggered in elevation, and follow-up operation and maintenance are guaranteed; and finally, '8 * 1 'distributed mooring is put forward to replace '4 * 2' symmetrical mooring, and mooring constraint optimization is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore wind power generation, and in particular to a novel five-column semi-submersible wind power foundation and a mooring system thereof. Background Art

[0002] In recent years, driven by the pressure of energy transformation, the offshore wind power industry has developed rapidly. At present, the offshore resources that have been carried out in the preliminary work and construction are approaching saturation. It is an inevitable trend for my country's offshore wind power development to move towards the deep sea. With the increase of water depth, the development cost of fixed offshore wind power will increase significantly, and the use of floating wind power technology has become an important means of developing wind energy resources in deep sea areas. At the same time, in recent years, offshore wind turbines have shown a large-scale development trend of 10MW+. The blade size and flexibility of units above 10MW are larger, and the corresponding floating foundation scale is also larger. Under the complex and harsh environmental conditions of the deep sea, the key technologies such as the force characteristics, coupling mechanism, and motion characteristics of the entire wind power system still need to be studied and verified.

[0003] Although floating wind power in my country has achieved a certain degree of development, it still needs to be broken through in general. On the one hand, due to the development of the upstream and downstream industrial chains at this stage, its development cost is still too high; on the other hand, the core technologies of deep sea conditions and 15MW+ large-capacity floating wind power full system in design, construction and construction need to be further developed, so that we can truly reduce costs and increase efficiency and make it have commercial development prospects. In addition, with an eye on the current development trend of large-scale units, the unit capacity is expected to increase to 20MW after 2025. However, the existing floating wind power technology obviously cannot meet the future development needs of offshore wind power. Therefore, it has become an inevitable trend to carry out adaptive research on deep sea and 20MW floating wind power.

[0004] The semi-submersible wind power foundation in the prior art generally has three side columns, and the three side columns form an equilateral triangle layout of a "herringbone". For example, in the prior art, there is a floating offshore semi-submersible structure wind power foundation platform and construction method with publication number CN117508488A, and a semi-submersible offshore wind power foundation structure with publication number CN204753618U, both of which improve the heave damping of the semi-submersible wind power foundation to a certain extent, increase the center of buoyancy and lower the center of gravity, greatly improve the stability of the semi-submersible wind power foundation, and improve the hydrodynamic performance of the semi-submersible wind power foundation.

[0005] However, facing the more complex and harsh marine environment with a water depth of more than 50m and large-capacity units with a single unit capacity of 15MW and above, the semi-submersible wind power foundation in the existing technology cannot meet the future development and construction needs of floating wind power. Based on the larger scale of the floating foundation under the large-capacity unit, its nonlinear movement under the combined action of wind, waves and currents is more significant, and the structural safety analysis under the multi-field multi-body coupling dynamic response of aerodynamics, hydrodynamics, mooring, structure, electrical and control is more complicated; and with the substantial increase in the capacity of wind turbines, the blade size and flexibility are larger. In the case of a large swing of the floating foundation, the coupling effect between large-capacity units, large-scale floating foundations and mooring systems is completely different from that of small-capacity units. The adaptability between the unit and the foundation lacks research and verification, and the unit's power generation and power generation efficiency, control strategy, and typhoon resistance performance also need further research. It is obvious that completely copying the solution in the existing technology cannot meet the needs, and its safety, stability and economy will also face greater challenges. Therefore, for water depths of more than 50m and large-capacity units of 15MW+, it is necessary to further study the semi-submersible foundation technology suitable for ultra-large capacity units. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a novel five-column semi-submersible wind power foundation and its mooring system, which are used to solve the problem that the semi-submersible wind power foundation in the prior art cannot meet the future floating wind power development and construction needs.

[0007] To achieve the above-mentioned purpose and other related purposes, the present invention provides a novel five-column semi-submersible wind power foundation, including an X-shaped pontoon, wherein the four ends of the X-shaped pontoon are provided with side columns, a central column is provided at the center of the X-shaped pontoon, and the four side columns are centrally symmetrically distributed about the central column; a tower is provided on the central column, a wind turbine is provided at the top of the tower, and the wind turbine converts wind energy into electrical energy; an outer platform is also provided on the outer peripheral surface of the junction of the central column and the tower.

[0008] Preferably, it also includes a plurality of deck passages, one end of which is fixedly arranged on the top surface of the side column, and the other end extends to the upper side of the outer platform; a ladder is also arranged between the deck passage and the outer platform; the deck passage is used for personnel passage and cargo transportation.

[0009] Preferably, the number of the deck passages is four, and the four deck passages are grouped in pairs, for a total of two groups of deck passages; a trapezoidal frame is provided between each group of deck passages.

[0010] Preferably, the axes of the four side columns are parallel to the axis of the central column.

[0011] Preferably, the horizontal cross-section of the central column is circular, and the diameter of the top end surface of the central column is the same as the diameter of the bottom end surface of the tower.

[0012] Preferably, the horizontal cross-section of the side column is circular or polygonal.

[0013] Preferably, the side columns, central columns and X-shaped pontoons are all hollow plate beam structural members.

[0014] Preferably, the diameters of the four side columns are all D1, the distance between two adjacent side columns is L, and the second-order moment of the waterplane area of ​​the semi-submersible wind power foundation with four side columns is:

[0015]

[0016] The second-order moment of the waterline area is used to determine the stability of the semi-submersible wind power foundation.

[0017] Preferably, the diameter of the side column of the semi-submersible wind power foundation with three side columns is D2, the distance between two adjacent side columns is L, and the second-order moment of the water plane area of ​​the semi-submersible wind power foundation with three side columns is:

[0018]

[0019] When the water plane area of ​​a semi-submersible wind turbine foundation with three side columns is the same as that of a semi-submersible wind turbine foundation with four side columns, the relationship between D1 and D2 is as follows:

[0020]

[0021] From formula (1), formula (2) and formula (3), we can get:

[0022]

[0023] Under the premise of the same waterplane area and the same side column span, the second-order moment of the waterplane area of ​​the semi-submersible wind turbine foundation with four side columns is greater than the second-order moment of the waterplane area of ​​the semi-submersible wind turbine foundation with three side columns.

[0024] To achieve the above purpose or other purposes, the present invention further discloses a mooring system, which is applied to the above-mentioned novel five-column semi-submersible wind power foundation, and two mooring cables are arranged on each side column.

[0025] The novel five-column semi-submersible wind power foundation and its mooring system according to the present invention have the following beneficial effects:

[0026] 1. The novel five-column semi-submersible wind power foundation and its mooring system involved in the present invention are suitable for 15MW+ and future large-scale wind turbines with more than 30MW. Based on the research of the existing technology on the semi-submersible foundation scheme with three side columns, a scheme with four side columns and one central column is proposed. At the same time, the above five columns are arranged on an X-shaped pontoon. Through the combination of the two, the technical shortcomings of insufficient stability and insufficient strength of the humanoid buoy in the semi-submersible foundation scheme with three side columns in the existing technology are greatly solved.

[0027] 2. The novel five-column semi-submersible wind turbine foundation and its mooring system involved in the present invention increase the three side columns that provide stability in the prior art to four side columns. When the waterplane area and span of the columns remain unchanged, the second-order moment of the waterplane area of ​​the semi-submersible foundation is greatly increased, thereby greatly improving the stability of the foundation.

[0028] 3. The novel five-column semi-submersible wind turbine foundation and its mooring system involved in the present invention install four side columns on the X-shaped pontoon in a centrally symmetrical manner, and transfer the load of the wind turbine set to the X-shaped pontoon. Compared with the humanoid pontoon design of "three side columns + central column", the X-shaped pontoon will have greater cross-sectional bending stiffness, torsional stiffness and shear stiffness at the same width and height, and its structural force characteristics are better.

[0029] 4. The novel five-column semi-submersible wind power foundation and its mooring system involved in the present invention have two mooring cables arranged on each side column, the angle between the two mooring cables is 90°, and a total of eight mooring cables are arranged on the four side columns, thus forming a "well" shape. When the wind power foundation is subjected to loads in any direction, two mooring cables are directly subjected to the force, which is more stable than the mooring system in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a spatial schematic diagram of the novel five-column semi-submersible wind power foundation of the present invention;

[0031] Figure 2 It is a schematic diagram of the second-order moment of the waterline area of ​​the novel five-column semi-submersible wind power foundation of the present invention;

[0032] Figure 3 It is a schematic diagram of the second moment of water plane area of ​​a wind power foundation with three side columns and one central column in the prior art;

[0033] Figure 4 A force diagram of a first mooring system according to the present invention;

[0034] Figure 5 A force diagram of a second mooring system according to the present invention;

[0035] Figure 6 The figure is a force diagram of the third mooring system involved in the present invention.

[0036] Description of reference numerals:

[0037] 1. X-shaped pontoon; 2. Side columns; 3. Center columns; 4. Outer platform; 5. Tower; 6. Deck passage; 7. Trapezoidal frame; 8. Wind turbine; 9. Mooring cable. DETAILED DESCRIPTION

[0038] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0039] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0040] like Figure 1-Figure 6 As shown, the present invention provides a novel five-column semi-submersible wind power foundation (hereinafter referred to as wind power foundation), including an X-shaped pontoon 1, four ends of the X-shaped pontoon 1 are vertically provided with side columns 2, a central column 3 is provided at the center of the X-shaped pontoon 1, and the four side columns 2 are centrally symmetrically distributed about the central column 3; a tower 5 is provided on the central column 3, and a wind turbine 8 is provided at the top of the tower 5, and the wind turbine 8 converts wind energy into electrical energy; an outer platform 4 is also provided on the outer peripheral surface of the junction of the central column 3 and the tower 5.

[0041] The novel five-column semi-submersible wind power foundation involved in the present invention will Figure 3 The "human-shaped" pontoon shown in the prior art is replaced by an X-shaped pontoon 1, and the load of the wind turbine 8 acts on the X-shaped pontoon 1. Compared with the "human-shaped" pontoon with the same width and height, it will have greater cross-sectional bending stiffness, torsional stiffness and shear stiffness, and better structural stress characteristics. Figure 3The scheme of "three side columns 2 + one central column 3" in the prior art shown in the document is modified into a scheme of "four side columns 2 + one central column 3". When the waterplane area of ​​the columns and the span of the columns remain unchanged, the second-order moment of the waterplane area of ​​the scheme of "four side columns 2 + one central column 3" in the present application is greatly increased, thereby greatly improving the stability of the wind power foundation.

[0042] In this embodiment, the X-shaped buoyancy tank 1 is also called "X-Floater".

[0043] Preferably, Figure 1 As shown, the wind power foundation also includes a plurality of deck passages 6, one end of which is fixedly arranged on the top surface of the side column 2, and the other end extends to the upper side of the outer platform 4; a ladder (not shown) is also arranged between the deck passage 6 and the outer platform 4; the deck passage 6 is used for personnel passage and cargo transportation. In this embodiment, the deck passage 6 adopts a round tube design, and the top surface of the round tube is also provided with corridors, railings and other auxiliary components for personnel passage and cargo transportation. One end of the ladder is connected to the deck passage 6, and the other end is on the upper side of the outer platform 4. The operator can enter the outer platform 4 through the side column 2, the deck passage 6 and the ladder.

[0044] Furthermore, in this embodiment, there are four deck passages 6, and the four deck passages 6 form a group of two, totaling two groups of deck passages 6; a ladder frame 7 is provided between each group of deck passages 6. The ladder frame 7 can be provided between two deck passages 6 adjacent in the horizontal direction, or between two deck passages 6 adjacent in the vertical direction, and the function of the ladder frame 7 is to transfer the force between the two side columns 2. In addition, the end of the ladder away from the outer platform 4 can be connected to the ladder frame 7.

[0045] Preferably, Figure 1 As shown, the axes of the four side columns 2 are parallel to the axis of the central column 3. The axes of the four side columns 2 and the axis of the central column 3 both extend in the vertical direction.

[0046] Preferably, Figure 1-Figure 3 As shown, the horizontal cross-section of the central column 3 is circular, and the diameter of the top end face of the central column 3 is the same as the diameter of the bottom end face of the tower 5. In this embodiment, the central column 3 is used to support the tower 5 and the wind turbine 8. The diameter of the top end face of the central column 3 is the same as the diameter of the bottom end face of the tower 5, which can better realize the connection between the central column 3 and the tower 5, and there is no need to design a transition section between the top end face of the central column 3 and the bottom end face of the tower 5, so that the load of the tower 5 and the wind turbine 8 is effectively transferred to the X-shaped pontoon 1 at the bottom.

[0047] Preferably, the horizontal cross-section of the side column 2 is circular or polygonal. In this embodiment, the side column 2 is connected by the X-shaped pontoon 1 below the waterline and by the deck channel 6 and the trapezoidal frame 7 above the waterline. The side column 2 is used to provide stability to ensure that the wind power foundation can stand under various working conditions. At the same time, the side column 2, the central column 3, and the X-shaped pontoon 1 are all cavity plate beam structural members. The side column 2 can provide a part of the buoyancy to ensure the movement performance of the semi-submersible wind power foundation.

[0048] Preferably, Figure 1 As shown, the outer platform 4 is arranged on the outer peripheral surface where the central column 3 and the tower 5 meet, and the shape of the outer platform 4 is rectangular, which can provide a larger deck area for placing equipment required for the operation and maintenance of the wind turbine 8, such as: diesel generators, cranes, dry-type transformers, operation and maintenance cabins, etc.

[0049] Preferably, Figure 2 , Figure 3 As shown in the figure, the stability of the semi-submersible wind turbine foundation mainly comes from the side columns 2, and the stability can be judged by the second-order moment of the waterline area of ​​the wind turbine foundation. Since the waterline area will affect the heave period, thereby affecting the heave motion performance of the semi-submersible wind turbine foundation, in order to more intuitively reflect the difference in stability between three side columns 2 and four side columns 2, the waterline areas of the two schemes should be the same, that is:

[0050] Need to meet Thus we get

[0051] Wherein, D1 is the diameter of four side columns 2 , and D2 is the diameter of three side columns 2 .

[0052] The second moment of waterline area of ​​a semi-submersible wind turbine foundation with four side columns is:

[0053]

[0054] The second-order moment of waterline area of ​​a semi-submersible wind turbine foundation with three side columns is:

[0055]

[0056] It can be seen from the above formula that the second moment of the waterplane area of ​​the semi-submersible wind turbine foundation with four side columns and two is greatly increased compared with the second moment of the waterplane area of ​​the semi-submersible wind turbine foundation with three side columns and two, that is, the stability of the semi-submersible wind turbine foundation with four side columns and two is greater than the stability of the semi-submersible wind turbine foundation with three side columns and two.

[0057] If the above formula If it is removed, then under the same column waterplane area and column span, the second moment of the waterplane area of ​​the semi-submersible wind turbine foundation with four side columns and 2 increases by 50% compared with the second moment of the waterplane area of ​​the semi-submersible wind turbine foundation with three side columns and 2.

[0058] The above-mentioned second-order moments of the waterplane area are calculated by being equivalent to the waterplane inertia moment of the X-axis. The second-order moments of the waterplane area in the above-mentioned formulas are calculated without considering the central column 3.

[0059] In summary, the obvious advantage of using four side columns 2 in improving the stability of the semi-submersible wind power foundation is that as the capacity of the wind turbine 8 increases, the wind thrust generated by the large-capacity unit under power generation conditions and typhoon extreme conditions is much greater than that of the wind turbine 8 within 10MW. In this case, in order to ensure the stability of the floating wind power foundation, the design of three side columns 2 often requires a larger side column 2 diameter and column span, refer to formula (2). However, increasing the side column 2 diameter and the side column 2 span will bring the following negative effects:

[0060] The negative effects of increasing the diameter of the side column 2 include: ① reducing the heave period of the semi-submersible wind turbine foundation, making it close to the wave period, thereby resonating with the waves; ② increasing the wave force of the semi-submersible wind turbine foundation, increasing the difficulty of mooring system design and increasing the amount of structural steel.

[0061] The negative effects of increasing the span of the side columns 2 include causing the deck, struts, and pontoons connecting the side columns 2 to be too long, and reducing the stiffness of the entire structure. In this case, in order to ensure the structural strength, it is necessary to design a stronger deck, strut, and pontoon structure to ensure the structural strength of the semi-submersible wind power foundation.

[0062] The above trade-off between increasing the diameter of the side column 2 and increasing the span of the side column 2 will bring troubles and design difficulties to the designer. No matter from which angle the increase is made, it will have a negative effect on the subsequent overall performance, mooring system and structural direction in order to improve stability, and ultimately lead to the redesign and selection of the entire solution. Therefore, in this case, the semi-submersible wind power foundation with four side columns 2 in this application has an improvement of about 50% in stability compared to the semi-submersible wind power foundation with three side columns 2. It can better balance between increasing the diameter of the side column 2 and increasing the span of the side column 2, and finally achieve a design balance between stability, overall performance, mooring system and structural strength.

[0063] To achieve the above purposes or other purposes, such as Figure 6As shown, the present invention further discloses a mooring system, which is applied to the above-mentioned novel five-column semi-submersible wind power foundation, and two mooring cables 9 are arranged on each side column 2. In this embodiment, two mooring cables 9 are arranged on each side column 2, and the number of side columns 2 is four, a total of eight mooring cables 9, and the eight mooring cables 9 are arranged in a "well" shape on the wind power foundation.

[0064] Preferably, according to environmental conditions, operation of wind turbine 8, displacement of semi-submersible wind turbine foundation and other requirements, mooring cable 9 can adopt one or more combinations of anchor chain, steel wire rope, polyester fiber, nylon rope, counterweight block, buoyancy block, etc. to achieve mooring of wind turbine foundation.

[0065] Preferably, in this embodiment, the eight mooring cables 9 can be connected to the wind turbine foundation according to the requirements of the movement performance, displacement, dynamic cable design, integrated load, etc. of the wind turbine foundation. The cable guide points of the eight mooring cables 9 can be set above or below the waterline. The specific positions of the cable guide points on the side columns 2 depend on the actual site, as long as they can meet the overall design requirements of the semi-submersible wind turbine foundation.

[0066] To more intuitively describe the use of eight distributed mooring cables 9 in this application, the effect of greater stability is as follows: Figure 4-Figure 6 The following are the force diagrams of several mooring systems:

[0067] The first mooring system: three side columns and 2 semi-submersible wind power foundation adopts a "3*3" mooring system

[0068] like Figure 4 As shown, the three side columns 2 of the semi-submersible wind power foundation involved in the prior art (background art) all adopt a "3*3" constraint mode of nine mooring cables 9 in total to limit the displacement of the wind power foundation and ensure that the mooring system will not break under extreme conditions. Each side column 2 adopts three mooring cables 9, and each bundle is arranged at 120 degrees (three mooring cables 9 form a bundle). Figure 4 The design of nine mooring cables 9 arranged symmetrically at 120°, "3*3", has two typical stress states as shown by the arrows. When the environmental direction acts from the left arrow, the semi-submersible wind power foundation will have a large displacement and a small mooring force; when the environmental direction acts from the right arrow, the semi-submersible wind power foundation will have a small displacement and a large mooring force, and it does not have a good constraint effect in all directions.

[0069] The second mooring system: Four side columns 2 semi-submersible wind power foundation adopts "4*2" distributed mooring system

[0070] like Figure 5 As shown, two mooring cables 9 are arranged on each of the four side columns 2 in the present application, for a total of eight mooring cables 9. Figure 4The nine mooring cables 9 in the mooring system reduce the number of mooring cables 9 and reduce the cost of the mooring system. Figure 3 The "3*2" method of six mooring cables 9 in total is basically unable to meet the production requirements, but the present application uses "4*2" of four side columns 2 with eight mooring cables 9 in total to meet the production requirements of the wind power foundation and is more economical.

[0071] However, if Figure 5 As shown, if the angle between the two mooring cables 9 on each side column 2 is small, Figure 5 In the environmental direction indicated by the middle arrow, the restraining effect of the mooring system is relatively weak, which is mainly manifested in that in the environmental direction indicated by the arrow, four mooring cables 9 in an inclined state on each side provide restoring force, and the restraining force of the mooring system is relatively weak.

[0072] The third mooring system: Four side columns and 2 semi-submersible wind power foundations adopt an "8*1" mooring system

[0073] like Figure 6 As shown, two mooring cables 9 are arranged on each of the four side columns 2 in the present application, for a total of eight mooring cables 9. Figure 4 The nine mooring cables 9 in the side column 2 reduce the number of mooring cables 9 and reduce the cost of the mooring system. At the same time, the angle between the two mooring cables 9 on each side column 2 is 90°, that is, the eight mooring cables 9 form a "well" shape. Figure 6 In the direction of the environmental action shown by the middle arrow, two mooring cables 9 will be directly stressed, and the effect is better than that in the figure. Figure 6 The eight mooring cables 9 have the same mooring constraints in the direction of 0-360°, so they have a better synergistic effect with the design of the semi-submersible wind power foundation of the four side columns 2 in this application.

[0074] The novel five-column semi-submersible wind power foundation and its mooring system according to the present invention have the following beneficial effects:

[0075] 1. The present invention can better solve the stability, strength and mooring system design problems faced by the floating foundation design caused by the large wind turbine load of the current large-capacity units. Compared with the three-side column 2 and four-side column 2 semi-submersible foundations currently used for units within 10MW, this solution is more adaptable to 15MW and above, even 20MW and 25MW, and the mooring system cost is lower.

[0076] 2. The present invention improves and optimizes the semi-submersible foundations with three side columns 2 and four side columns 2 that are currently used in engineering practice, and innovatively proposes a semi-submersible foundation design scheme of "four side columns 2 + central column 3 + X-shaped pontoon 1" and a "tic-tac-toe" mooring system specially designed for this foundation type. Compared with the existing semi-submersible foundation and mooring system design scheme, this application can better solve the problems of semi-submersible wind power foundation stability and structural strength design caused by excessive aerodynamic loads of 15MW and 20MW large-capacity wind turbines 8, as well as the problem of high cost of the "3*3" nine-bar mooring system with three side columns 2.

[0077] 3. The X-shaped pontoon 1 in the present invention is used to bear the entire load of the wind turbine 8, which can play a beneficial effect of lowering the center of gravity. The entire load of the wind turbine 8 is transferred to the lower part of the X-shaped pontoon 1, so that the center of gravity of the steel structure of the entire semi-submersible wind power foundation will be very low, which is very friendly to its stability.

[0078] 4. The X-shaped pontoon 1 in the present invention adopts a rectangular cross-section design. Compared with a circular cross-section, a rectangular cross-section not only has a larger additional mass and a sectional inertia moment, but also helps to improve the motion performance and structural strength of the semi-submersible wind power foundation. For the design of the X-shaped pontoon 1, its aspect ratio is greater than 1 in order to obtain a larger additional mass.

[0079] 5. The angle between the X-shaped pontoons 1 in the present invention is 90°. Compared with the 120° pontoon solution that may be adopted by the three-side columns 2, the 90° X-shaped pontoon 1 has better structural rigidity. In the application, the wind turbine load will directly act on the pontoon. The improvement in structural rigidity brought about by the design of the X-shaped pontoon 1 will be more conducive to the structural design in this application and reduce the amount of structural steel.

[0080] 6. The novel five-column semi-submersible wind power foundation and its mooring system involved in the present invention transfer all the deck, cross brace and diagonal brace force systems in the prior art to the lower X-shaped pontoon 1, which not only utilizes the good force characteristics of the X-shaped pontoon 1, but also makes the center of gravity of the entire structure concentrated underwater, preventing the occurrence of insufficient stability due to excessively high center of gravity. The novel five-column semi-submersible wind power foundation and its mooring system involved in the present invention separate the force system of the side column 2 from the force system of the center column 3 in the prior art. The center column 3 and the X-shaped pontoon 1 are used to bear all wind turbine loads and wave loads, and the side column 2 only bears wave loads; at the same time, through the design concept of the staggered elevation of the deck passage 6 and the outer platform 4, the side column 2 and the center column 3 can be connected to ensure the passage of personnel and subsequent engineering operation and maintenance. The novel five-column semi-submersible wind turbine foundation and its mooring system involved in the present invention change the mooring system arranged symmetrically in a "bundle" in the prior art into a distributed mooring system, and change the originally commonly used "4x2" mooring system into an "8x1" mooring system, thereby giving full play to the restraining effect of each mooring cable.

[0081] Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0082] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A new type of five-column semi-submersible wind power foundation, characterized by: The invention comprises an X-shaped pontoon (1), wherein the four ends of the X-shaped pontoon (1) are each provided with side columns (2), a central column (3) is provided at the center of the X-shaped pontoon (1), and the four side columns (2) are centrally symmetrically distributed about the central column (3); a tower (5) is provided on the central column (3), a wind turbine (8) is provided at the top of the tower (5), and the wind turbine (8) converts wind energy into electrical energy; and an outer platform (4) is also provided on the outer peripheral surface of the junction between the central column (3) and the tower (5).

2. The novel five-column semi-submersible wind power foundation according to claim 1 is characterized in that: It also comprises a plurality of deck passages (6), one end of which is fixedly arranged on the top surface of the side column (2), and the other end of which extends to the upper side of the outer platform (4); a ladder is also arranged between the deck passage (6) and the outer platform (4); the deck passage (6) is used for the passage of personnel and the transportation of goods.

3. The novel five-column semi-submersible wind power foundation according to claim 2 is characterized in that: The number of the deck passages (6) is four, and the four deck passages (6) are grouped in pairs, for a total of two groups of deck passages (6); a trapezoidal frame (7) is provided between each group of deck passages (6).

4. The novel five-column semi-submersible wind power foundation according to claim 1 is characterized in that: The axes of the four side columns (2) and the axis of the central column (3) are parallel to each other.

5. The novel five-column semi-submersible wind power foundation according to claim 1 is characterized in that: The horizontal cross-section of the central column (3) is circular, and the diameter of the top end surface of the central column (3) is the same as the diameter of the bottom end surface of the tower (5).

6. The novel five-column semi-submersible wind power foundation according to claim 1 is characterized by: The horizontal cross-section of the side column (2) is circular or polygonal.

7. The novel five-column semi-submersible wind power foundation according to claim 1 is characterized by: The side columns (2), the central column (3) and the X-shaped pontoon (1) are all hollow plate beam structural members.

8. The novel five-column semi-submersible wind power foundation according to claim 1 is characterized by: The diameters of the four side columns (2) are all D1, the distance between two adjacent side columns (2) is L, and the second-order moment of the water plane area of ​​the semi-submersible wind power foundation with four side columns (2) is: The second-order moment of the waterline area is used to determine the stability of the semi-submersible wind power foundation.

9. The novel five-column semi-submersible wind power foundation according to claim 8 is characterized in that: The diameter of the side columns (2) of the semi-submersible wind power foundation with three side columns (2) is D2, the distance between two adjacent side columns (2) is L, and the second-order moment of the water plane area of ​​the semi-submersible wind power foundation with three side columns (2) is: When the water plane area of ​​the semi-submersible wind turbine foundation with three side columns (2) is the same as the water plane area of ​​the semi-submersible wind turbine foundation with four side columns (2), the relationship between D1 and D2 is as follows: From formula (1), formula (2) and formula (3), we can get: On the premise that the waterplane area is the same and the span of the side columns (2) is the same, the second-order moment of the waterplane area of ​​the semi-submersible wind power foundation with four side columns (2) is greater than the second-order moment of the waterplane area of ​​the semi-submersible wind power foundation with three side columns (2).

10. A mooring system, applied to the novel five-column semi-submersible wind power foundation according to any one of claims 1 to 9, characterized in that: Two mooring cables (9) are arranged on each side column (2).

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