A floating tension leg wind turbine platform foundation

Abstract

The utility model belongs to offshore wind power field, including center float, side float, cross brace, tension tendon and auxiliary float, wherein, cross brace is used for connecting two side floats, tension tendon sets in the lower end of side float, auxiliary float is shaped as the cylinder of first through -hole setting along the axial direction, the space between the hole wall curved surface of first through -hole and the outside of cylinder is hollow accommodating space, wherein, auxiliary float sets up on cross brace through the first through -hole of two bottom surface, the accommodating space of auxiliary float is used for loading or unloading ballast water, wherein, the displacement of auxiliary float is less than center float and side float, the utility model provides redundancy buoyancy through auxiliary float, reduces the steel consumption of platform float, thereby saves the cost, and has the effect of protecting cross brace, adjusting float ballast water, thereby reduces the possibility of platform damage repair and instability.

Description

Technical Field

[0001] This utility model belongs to the field of offshore wind power and relates to the foundation of a floating tension leg wind turbine platform. Background Technology

[0002] With the continuous transformation and development of the global energy structure, the development of offshore wind power resources has attracted much attention, and deep-sea areas are becoming increasingly popular due to their abundant wind resources and better power generation stability. Currently, floating wind power platforms suitable for deep-water development mainly include: semi-submersible platforms, spar platforms, barge platforms, and tension leg platforms (TLPs). Tension leg platforms are semi-compliant, semi-rigid floating deep-water platforms. Their core feature is the use of tensioned steel cables to anchor the platform body to the seabed, resulting in minimal motion response under wind and wave action. Furthermore, tension leg platforms have a small sea area footprint and require less steel, significantly reducing development costs and making them suitable for deep-water operations. In recent years, the design and development of tension leg floating wind turbines have increased significantly.

[0003] Tension leg platforms typically require temporary ballast tanks during maritime transport to lower the platform's center of gravity and enhance overall structural stability on board. The pontoons have a very large displacement, making precise adjustments to the ballast water volume to regulate draft extremely difficult. During offshore installation, achieving precise pre-tensioning of the tension tendons by adjusting the platform's pontoons is also challenging. While tension leg platforms use less steel compared to semi-submersible or other floating platforms in offshore wind power applications, their pontoons still need sufficient volume and steel to accommodate the pumped ballast water, lowering the overall center of gravity and maintaining stability. Achieving comparable buoyancy while reducing steel consumption can significantly save costs. Offshore wind turbine platforms may also experience unexpected situations, such as impacts from ships, ice floes, or marine life, directly damaging the cross braces and other components. Utility Model Content

[0004] To address the issues of providing redundant buoyancy for auxiliary pontoons while protecting the cross braces and adjusting the ballast water volume of the pontoons, a floating tension leg fan platform foundation is provided according to some specific embodiments of this application, including...

[0005] Center buoy;

[0006] Side floats;

[0007] A cross brace, used to connect the two side buoys;

[0008] Tension ribs, wherein the tension ribs are disposed at the lower end of the side floats;

[0009] An auxiliary buoy is formed as a column with a first through hole along the axial direction, and the space between the curved surface of the first through hole wall and the outer surface of the column is a hollow accommodating space.

[0010] The auxiliary buoy is mounted on the cross brace through a first through hole between two bottom surfaces, and the accommodating space of the auxiliary buoy is used for loading or unloading ballast water.

[0011] The auxiliary buoy has a smaller displacement than the central buoy and the side buoys.

[0012] According to the floating tension leg wind turbine platform foundation in some specific embodiments of this application, the auxiliary pontoon includes a semi-floating body, which includes a first semi-floating body and a second semi-floating body. The first semi-floating body and the second semi-floating body are detachably connected and formed into an auxiliary pontoon through the detachable connection.

[0013] According to the floating tension leg fan platform foundation in some specific embodiments of this application, the semi-floating body is formed into a semi-circular annular cylinder, including an outer semi-circular curved surface, an inner semi-circular curved surface, a bottom connecting surface and a side connecting surface, a hollow accommodating space between the outer semi-circular curved surface and the inner semi-circular curved surface, and a sealable water inlet provided on the bottom connecting surface.

[0014] According to the floating tension leg fan platform foundation in some specific embodiments of this application, the outer side of the semi-floating body is provided with at least one mounting groove, and the side connecting surface of the semi-floating body is formed into a mounting part with a certain thickness in the direction of the mounting groove itself, and the mounting part is provided with a second through hole in the thickness direction.

[0015] Detachable connection structure, including

[0016] A connecting pipe, the inner circumference of which is threaded, is disposed in the second through hole of the mounting portion of the first semi-float and the second semi-float;

[0017] The first bolt is located in the mounting groove of the first semi-floating body and is fixed in the connecting pipe in the second through hole by means of threaded connection, and the bottom surface of the nut of the first bolt abuts against the wall surface of the mounting part of the first semi-floating body.

[0018] The second bolt is located in the mounting groove of the second semi-float and is fixed in the connecting pipe in the second through hole by means of threaded connection, and the bottom surface of the nut of the second bolt abuts against the wall surface of the mounting part of the second semi-float.

[0019] According to the floating tension leg fan platform foundation in some specific embodiments of this application, the nuts of the first bolt and / or the second bolt are provided with protective caps.

[0020] According to some specific embodiments of the floating tension leg fan platform foundation of this application, the protective cover is a plastic protective cover, and a magnetic absorbing sheet is provided inside the protective cover.

[0021] According to the floating tension leg fan platform foundation in some specific embodiments of this application, at least two sets of auxiliary pontoons are provided on each of the cross braces. One set of auxiliary pontoons is positioned on the cross brace close to one of the side pontoons connected to both ends of the cross brace, and the other set of auxiliary pontoons is positioned on the cross brace close to another side pontoon connected to both ends of the cross brace. Each set of auxiliary pontoons includes at least one auxiliary pontoon.

[0022] According to the floating tension leg wind turbine platform foundation in some specific embodiments of this application, a group of auxiliary pontoons includes at least two auxiliary pontoons, and the auxiliary pontoons in the group are arranged in a row along the axial direction of the cross brace.

[0023] According to the floating tension leg fan platform foundation in some specific embodiments of this application, the side floats include a first side float, a second side float, and a third side float, and the cross braces include a first cross brace, a second cross brace, and a third cross brace.

[0024] It also includes inner transverse braces, which include a first inner transverse brace, a second inner transverse brace, and a third inner transverse brace;

[0025] Wherein, the first side buoy and the second side buoy are connected by the first cross brace, the second side buoy and the third side buoy are connected by the second cross brace, and the third side buoy and the third side buoy are connected by the third cross brace, so that the side buoys and the cross braces are assembled into an equilateral triangle;

[0026] The central pontoon is located at the center of the equilateral triangle;

[0027] The central buoy is connected to the first side buoy via a first inner cross brace, to the second side buoy via a second inner cross brace, and to the third side buoy via a third inner cross brace.

[0028] According to the floating tension leg fan platform foundation in some specific embodiments of this application, the shell of the auxiliary pontoon is made of polyethylene material; the volume ratio of the side pontoon to the auxiliary pontoon is (30~50):1.

[0029] Beneficial effects:

[0030] This invention, by incorporating auxiliary pontoons, provides redundant buoyancy to the platform, reducing the buoyancy requirements of the platform's pontoons (center and side pontoons). This allows for a reduction in the size of the platform pontoons to some extent, while maintaining the platform's original buoyancy. The reduced size of the platform pontoons also reduces steel consumption, saving costs. Furthermore, the auxiliary pontoons can be manufactured using lightweight materials such as polyethylene, effectively replacing steel with lightweight materials, further reducing steel consumption and saving costs.

[0031] Based on the above, compared with the large-capacity ballast water regulation of the center buoy and side buoy, the auxiliary buoy achieves small-value ballast water regulation within a certain range, which is more precise for ballast water regulation. Compared with the large-capacity ballast water regulation of the center buoy and side buoy, it can reduce the difficulty of regulation to a certain extent.

[0032] Based on the above, this utility model is equipped with an auxiliary buoy, which can adjust the ballast water volume to achieve stability adjustment of the floating tension leg wind turbine platform foundation on the semi-submersible barge during the transportation phase, eliminating the need to add a temporary ballast water tank.

[0033] Based on the above, it can also precisely adjust the pretension of the tension tendon during the installation phase.

[0034] Based on the above, during the maintenance phase, it can play a transitional adjustment role, avoiding direct adjustment of the ultra-large capacity ballast water of the main and side buoys during maintenance, thus gaining more time for emergency repairs before necessary adjustment of the ultra-large capacity ballast water.

[0035] Based on the above, during the platform's operational cycle, the auxiliary buoys also serve to protect the cross braces, reducing the risk of ground-induced damage to the cross braces caused by special operations such as anchoring. Damage to the cross braces leads to significant repair difficulties and may cause platform instability. Due to their detachable, easily replaceable, and lower-cost characteristics, the auxiliary buoys protect the cross braces, reducing the likelihood of platform damage requiring repair and instability.

[0036] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0037] Figure 1 This is a technical roadmap for implementing this utility model.

[0038] Figure 2 This is a schematic diagram of the structure of the semi-floating body and its connecting parts of this utility model.

[0039] Figure 3 This is a schematic diagram of the overall structure of the floating body connector.

[0040] Figure 4 This is a schematic diagram of the overall structure of the pontoon.

[0041] Figure 5 This is a schematic diagram of the foundation installation and transportation of a floating tension leg fan platform.

[0042] Figure 6 This is a schematic diagram of the foundation installation and transportation of the wind turbine and the floating tension leg wind turbine platform.

[0043] Figure 7 This is a schematic diagram of the tension leg floating fan structure in place.

[0044] Figure 8 This is a schematic diagram of the inside of the pontoon.

[0045] Figure 9 This is another schematic diagram of the overall structure of the pontoon.

[0046] Figure label:

[0047] 1. Semi-floating body;

[0048] 2. Connecting parts; 21. Bolts; 22. Connecting pipes;

[0049] 3. Protective cover; 31. Magnetic clip;

[0050] 4. Auxiliary pontoons;

[0051] 5. Hollow groove;

[0052] 6. Water inlet and outlet holes;

[0053] 7. Air inlet and outlet;

[0054] 8. Horizontal brace;

[0055] 9. Foundation for floating tension leg fan platform;

[0056] 10. Semi-submersible barge;

[0057] 11. Tugboat;

[0058] 12. Upper fan;

[0059] 13. Tension tendons;

[0060] 14. Suction anchor;

[0061] 15. Side floats. Detailed Implementation

[0062] The embodiments of this application are described in detail below with reference to the accompanying drawings, examples of which are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0063] Currently, the towing and transportation of floating wind turbines are mainly divided into two methods: dry towing and wet towing. Dry towing requires consideration of more factors and is suitable for long-distance transportation; wet towing is relatively slower and is more suitable for short-distance transportation. For example, the world's first floating wind power project using tension leg foundations—the Provence Grand Large (PGL) project—used wet towing for its platform transportation. Because the draft of the floating tension leg wind turbine platform foundation is relatively small, temporary ballast tanks are usually required during wet towing to lower the platform's center of gravity and enhance the overall structural stability on the ship.

[0064] Floating tension leg wind turbine platform foundations are a type of semi-compliant, semi-rigid floating deep-water platform. Their core feature lies in anchoring the platform body to the seabed using tensioned steel cables, resulting in minimal motion response under wind and wave action. Furthermore, floating tension leg wind turbine platform foundations occupy a small sea area and require less steel, significantly reducing development costs and making them suitable for deep-water operations. In recent years, the design and development of tension leg floating wind turbines have increased considerably. Tension leg floating wind turbines rely on a lower floating body to provide buoyancy to the overall structure (including the wind turbine, tower, and support platform). The portion of buoyancy exceeding the structure's self-weight is balanced by pre-tension generated by tension tendons. This pre-tension setting greatly ensures the overall stability of the platform. During installation in the sea area of ​​a floating offshore wind power system, one end of the tension tendon is connected to a suction anchor installed on the seabed, and then the other end is connected to a side buoy. The draft of the wind turbine foundation is adjusted to ensure the tension tendon reaches the predetermined tension requirements. However, the buoy capacity of large platform projects is extremely large, reaching 1600-2000 tons or even higher. Adjusting the ballast water volume to regulate draft is extremely difficult and precise, potentially leading to insufficient pretension of the tension tendons. This is particularly challenging during deep-sea installations, where environmental conditions are highly demanding and unpredictable, making water volume adjustment for ultra-large capacity floats even more difficult and operationally demanding. Careless operation during installation could result in accidents such as tendon rupture.

[0065] Floating pontoons may be subject to sudden accidents such as impacts from ships, ice floes, or marine life, causing compartment damage and potentially leading to overall structural failure or even destruction. For example, damage to side pontoons causing leaks or water ingress can cause platform instability. Repairs often require adjustments to stability, typically involving changes to the pontoon ballast water level. In such cases, due to the pontoons' large capacity, adjustments are highly complex and difficult, lacking convenient transitional adjustment methods. Furthermore, special operations such as anchor towing can damage the cross bracing.

[0066] Figure 1This is an implementation roadmap for the transportation, installation, and maintenance of a floating tension leg wind turbine platform foundation. This invention utilizes a detachable small pontoon, namely the auxiliary pontoon 4, which is integrally mounted on the cross brace 8 of the floating tension leg wind turbine platform foundation. During the installation and transportation of the floating platform and the upper wind turbine, ballast water is pumped into the auxiliary pontoon to ballast the platform, improving the overall structural stability. When installing the tension ribs 13, the ballast water volume of the platform-side pontoons 15 and the small pontoon is adjusted, allowing for more precise control of the platform's lifting and lowering and adjustment of pretension, simplifying the installation of the tension ribs 13. During maintenance, the small pontoon provides redundant buoyancy for the entire platform. Furthermore, due to its small size and distribution on the cross brace 8, even partial damage will not affect the overall stability of the platform, and installation and replacement can be performed manually or using an underwater robot.

[0067] One embodiment of this application discloses a floating tension leg wind turbine platform foundation, comprising a central pontoon, side pontoons 15, a cross brace 8, a tension rib 13, and an auxiliary pontoon 4. The cross brace 8 connects the two side pontoons; the tension rib 13 is disposed at the lower end of the side pontoons 15; the auxiliary pontoon 4 is formed as a column with a first through hole along its axial direction, and the space between the curved surface of the first through hole wall and the outer surface of the column is a hollow accommodating space; wherein, the auxiliary pontoon 4 is disposed on the cross brace 8 through the first through hole between the two bottom surfaces, and the accommodating space of the auxiliary pontoon 4 is used for loading or unloading ballast water; the ballast water capacity of the auxiliary pontoon 4 is smaller than that of the central pontoon and the side pontoons 15.

[0068] This invention utilizes detachable miniature pontoons, which are integrally mounted on the cross braces of the floating tension leg wind turbine platform foundation. This provides redundant buoyancy to the platform. While maintaining essentially the same buoyancy, the miniature pontoons can be made of lightweight materials, reducing the steel consumption of the central and side pontoons and saving costs. Since the detachable miniature pontoons are mounted on the cross braces, they also protect the cross braces. In the event of a breach in a side pontoon due to an emergency, the ballast water volume inside the miniature pontoons can be adjusted to help maintain platform stability, preventing capsizing and other major failures for a certain period. Furthermore, because they are made of HDPE, a cost-effective and small material, even partial damage will not affect the overall stability of the platform. Installation and replacement can be performed manually or using an underwater robot, resulting in low costs.

[0069] The auxiliary float 4 includes a semi-floating body 1, which comprises a first semi-floating body and a second semi-floating body. The first and second semi-floating bodies are detachably connected and formed into the auxiliary float 4 through this detachable connection. Preferably, the semi-floating body 1 is formed into a semi-circular annular cylinder, including an outer semi-circular curved surface, an inner semi-circular curved surface, a bottom connecting surface, a side connecting surface, a hollow accommodating space between the outer and inner semi-circular curved surfaces, and a sealable water inlet provided on the bottom connecting surface.

[0070] The side connecting surface of the semi-floating body 1 is formed into a mounting part with a certain thickness facing its own mounting groove. The mounting part is provided with a second through hole in the thickness direction. The detachable connection structure includes a connecting pipe 22, the inner circumference of which is provided with threads and is set in the second through hole of the mounting part of the first semi-floating body and the second semi-floating body. A first bolt 21 is provided in the mounting groove of the first semi-floating body and is fixed in the connecting pipe 22 in the second through hole by means of threaded connection, and the bottom surface of the nut of the first bolt 21 abuts against the wall surface of the mounting part of the first semi-floating body 1. A second bolt 21 is provided in the mounting groove of the second semi-floating body and is fixed in the connecting pipe 22 in the second through hole by means of threaded connection, and the bottom surface of the nut of the second bolt 21 abuts against the wall surface of the mounting part of the second semi-floating body 1.

[0071] Protective covers 3 are provided on the nuts of the first bolt 21 and / or the second bolt 21. Preferably, the protective cover 3 is a plastic protective cover 3, and a magnetic strip 31 is provided inside the protective cover 3.

[0072] At least two sets of auxiliary pontoons 4 are provided on each cross brace 8. One set of auxiliary pontoons 4 is positioned on the cross brace 8 close to one of the side pontoons 15 connected to both ends of the cross brace 8, and the other set of auxiliary pontoons 4 is positioned on the cross brace 8 close to the other side pontoon 15 connected to both ends of the cross brace 8. Each set of auxiliary pontoons 4 includes at least one auxiliary pontoon 4. Preferably, each set of auxiliary pontoons 4 includes at least two auxiliary pontoons 4, and the auxiliary pontoons 4 in the set are arranged in a row along the axial direction of the cross brace 8.

[0073] The side buoy 15 includes a first side buoy, a second side buoy, and a third side buoy; the cross brace 8 includes a first cross brace, a second cross brace, and a third cross brace; it also includes an inner cross brace, which includes a first inner cross brace, a second inner cross brace, and a third inner cross brace; wherein the first side buoy and the second side buoy are connected by the first cross brace 8, the second side buoy and the third side buoy are connected by the second cross brace 8, and the third side buoy and the first side buoy are connected by the third cross brace 8, so that the side buoy 15 and the cross brace 8 are assembled into an equilateral triangle; wherein the central buoy is located at the center of the equilateral triangle; wherein the central buoy is connected to the first side buoy through the first inner cross brace, to the second side buoy through the second inner cross brace, and to the third side buoy through the third inner cross brace. Preferably, the shell of the auxiliary buoy 4 is made of polyethylene material; the volume ratio of the side buoy 15 to the auxiliary buoy 4 is 30~50:1.

[0074] Another embodiment of this application discloses a pontoon, which may be referred to as auxiliary pontoon 4. The pontoon structure is shown in the reference diagram. Figure 2 , Figure 3 and Figure 4The auxiliary buoy 4 includes a first semi-buoy 1, a second semi-buoy 1, connectors 2, and protective covers 3. The auxiliary buoy 4 is composed of two symmetrical semi-buoys 1 joined together. The auxiliary buoy 4 has slots for the connectors 2 to pass through, and the two buoys are locked and fixed together by the connectors 2. The connectors 2 are distributed in two rows on the upper and lower parts of the buoy, with a total of eight connectors. Waterproof and corrosion-resistant protective covers 3 are provided at both ends of the eight connectors.

[0075] Reference Figure 2 To facilitate the installation and disassembly of the auxiliary float 4, inlet / outlet holes 6 and air inlet / outlet holes 7 are provided on one side of the float 1. During installation, ballast water is injected into the inlet / outlet holes 6 using an external ballast pump. Simultaneously, to prevent excessive pressure in the float 1, the air inlet / outlet holes 7 are opened to release air. After ballasting is completed, the external ballast device is removed, and the inlet / outlet holes 6 and 7 are closed, allowing the float 1 to sink to the designated position and be fitted onto the cross brace 8. Then, the connecting parts are installed, thus completing the installation of the auxiliary float 4. The semi-floating body 1 is equipped with a water inlet, which can be sealed with a cover or other sealing structure, such as a gasket. When it is necessary to drain water from the auxiliary float 4, the inlet / outlet holes 6 and 7 are opened. Compressed air is injected into the air inlet / outlet holes 7 to discharge water through the inlet / outlet holes 6. Alternatively, other methods of water extraction, such as pumps, can also be used. When water needs to be injected, the air inlet / outlet 7 can be closed as needed, and water can be introduced through the water inlet / outlet 6 using a pump or similar device. This invention provides one water inlet / outlet 6 and one air inlet / outlet 7 on each float piece. Ballast water is injected into the float via an external water pump to achieve ballast during the transport of the small floats. Simultaneously, the air inlet / outlet 7 is used to expel excess air from the float, ensuring pressure balance inside and outside the float. The water injection device in the float is a ballast water pump. The device for introducing air and expelling water from the float is a closed-loop air compressor.

[0076] Reference Figure 3 The connector 2 consists of two bolts 21 and a connecting pipe 22. The connecting pipe 22 is inserted into the auxiliary float 4. The connecting pipe 21 has internal threads, and its two ends are connected with bolts 21 to lock and fix the auxiliary float 4. The side connecting surface of the semi-float is formed into a mounting part with a certain thickness facing its own mounting groove. The mounting part has a second through hole in the thickness direction for fixing the connecting pipe 22. It can be understood that the mounting groove and the mounting part are not connected to the internal accommodating space. The bottom surface of the nut of one bolt abuts against the wall surface of the mounting part of the first semi-float 1, and the bottom surface of the nut of the other bolt abuts against the wall surface of the mounting part of the second semi-float 1, thereby securing the two semi-floats.

[0077] Reference Figure 3Because bolt 21 is immersed in seawater for a long time, it is very easy to corrode, which may cause loosening of the connection of auxiliary buoy 4 and damage to the overall structure. A protective cover 3 made of plastic material with certain corrosion resistance is installed on the outside of bolt 21. A magnetic absorbing piece 31 is installed on the inside of the protective cover 3. The protective cover 3 is tightly connected to bolt 21 through the magnetic absorbing piece 31, which plays the role of protecting bolt 21, preventing rust and stabilizing the structure.

[0078] Reference Figure 4 and Figure 5 , Figure 8 and Figure 9 In order to enable the novel auxiliary pontoon 4 designed in this study to be fitted onto the cross brace 8 of the floating tension leg fan platform foundation 9, a hollow groove 5, i.e. the first through hole, is provided inside the auxiliary pontoon 4. The inner diameter of the hollow groove 5 is the same as the inner diameter of the cross brace 8 of the floating tension leg fan platform foundation, so that the hollow groove 5 can fit tightly with the cross brace 8 and achieve overall structural stability.

[0079] In one embodiment, the side pontoon 15 has a capacity of 1600~2000 tons, and the auxiliary pontoon has a capacity of 40~50 tons, with a volume ratio of approximately 40:1. The specific dimensions and capacities can be adjusted according to the actual structural design.

[0080] Reference Figure 5 For the tension leg floating platform 9, which is the foundation of the floating tension leg wind turbine platform, which has been constructed on land, it can be placed on a semi-submersible barge 10 and transported to the wind turbine installation dock by tugboat 11 using a wet towing method for the installation of the upper wind turbine. At the same time, an appropriate number of auxiliary buoys 4 are installed on the cross braces 8 of the tension leg floating platform, and ballast water is injected into the auxiliary buoys 4 to lower the center of gravity of the platform, thereby improving the stability of the floating tension leg wind turbine platform foundation 9 during transportation.

[0081] Reference Figure 6 After the upper wind turbine 12 is transported to the installation dock via the floating tension leg wind turbine platform foundation 9, the upper wind turbine 12 and the floating tension leg wind turbine platform foundation 9 are installed by hoisting. At the same time, an appropriate number of auxiliary pontoons 4 are installed to increase ballast and maintain the overall stability of the wind turbine and platform. The turbine is then transported to the project sea area by wet towing for the installation of the substructure.

[0082] Reference Figure 6 and Figure 7After transporting the entire structure to the project area, the auxiliary buoys 4 are first installed on the cross braces 8 of the floating tension leg wind turbine platform foundation 9. Then, the semi-submersible barge is moved away, and the platform 9 is connected to the tugboat 11 via cables to maintain the stability of the overall structure. Next, water is injected into the side buoys 15 using their built-in ballast pumps to sink the entire structure to the designated depth for the installation of the tension tendons 13. The suction anchor 14 is pre-driven into the seabed, and then one end of the tension tendon 13 is connected to the suction anchor 14, and the other end is connected to the side buoy 15. After the two ends of the tension tendon 13 are connected, the tendon is pre-tensioned. First, the tension tendon is pre-tensioned by adjusting the ballast water volume inside the three side buoys 15, ensuring the pre-tension force of the tension tendon 13 reaches the set value. Then, based on the actual situation during installation, the tension of each tension tendon 13 is adjusted by adjusting the water volume inside the auxiliary buoys 4 on each cross brace 8, achieving the predetermined tension and completing the second pre-tensioning of the tendon. During the two pre-tensioning processes, the length and pre-tension force of each tendon were precisely controlled to ensure that the tendons were neither over-tensioned nor loosened. After the tendons were installed, the tugboat was driven away, all temporary structures were removed, and the entire installation was completed.

[0083] Another embodiment of this application discloses a floating offshore wind power generation system, including a wind turbine 12 and a floating tension leg wind turbine platform foundation 9, which supports the wind turbine 12. The floating tension leg wind turbine platform foundation 9 includes a central buoy, side buoys 15, a cross brace 8, and an auxiliary buoy 4. The cross brace 8 is used to connect the two side buoys. The auxiliary buoy 4 is formed as a column with a first through hole along the axial direction. The space between the curved surface of the first through hole wall and the outer surface of the column is a hollow accommodating space. The auxiliary buoy 4 is set on the cross brace 8 through the first through hole between the two bottom surfaces. The accommodating space of the auxiliary buoy 4 is used to load or unload ballast water. The ballast water capacity of the auxiliary buoy 4 is smaller than that of the central buoy and the side buoys 15. In one embodiment, the floating tension leg wind turbine platform foundation 9 also includes a tension tendon 13, which is located at the lower end of the side buoy 15. One end of the tension tendon 13 is connected to the side buoy, and the other end is connected to the suction anchor on the seabed. Preferably, the lower end of the side buoy is provided with a cable guide hole on the bottom or side to install the tension tendon 13.

[0084] In one embodiment, the floating tension leg wind turbine platform foundation 9 further includes support columns, inner horizontal braces, and diagonal braces. The inner horizontal braces include a first inner horizontal brace, a second inner horizontal brace, and a third inner horizontal brace; the diagonal braces include a first diagonal brace, a second diagonal brace, and a third diagonal brace. The side pontoons 15 of the floating tension leg wind turbine platform foundation 9 include a first side pontoon, a second side pontoon, and a third side pontoon, and the horizontal braces 8 include a first horizontal brace, a second horizontal brace, and a third horizontal brace. The first horizontal brace 8 connects the first side pontoon to the second side pontoon, and the second horizontal brace 8 connects the second side pontoon to the third side pontoon. A third cross brace 8 connects the third side buoy to the first side buoy, so that the side buoy 15 and the cross brace 8 are assembled into an equilateral triangle; wherein, the central buoy is located at the center of the equilateral triangle, and the support column is located on the central buoy; wherein, the central buoy is connected to the first side buoy through the first inner cross brace, connected to the second side buoy through the second inner cross brace, and connected to the third side buoy through the third inner cross brace; wherein, the support column is connected to the first side buoy through the first diagonal brace, connected to the second side buoy through the second diagonal brace, and connected to the third side buoy through the third diagonal brace.

[0085] In one embodiment, the auxiliary float 4 includes a semi-floating body 1, which comprises a first semi-floating body and a second semi-floating body. The first and second semi-floating bodies are detachably connected, forming the auxiliary float 4 through this detachable connection. The semi-floating body 1 is formed as a semi-circular annular cylinder, including an outer semi-circular curved surface, an inner semi-circular curved surface, a bottom connecting surface, a side connecting surface, a hollow accommodating space between the outer and inner semi-circular curved surfaces, and a sealable water inlet provided on the bottom connecting surface. The outer side of the semi-floating body 1 is provided with at least one mounting groove, and the side connecting surface of the semi-floating body 1 is formed into a mounting part with a certain thickness facing its mounting groove. The mounting part has a second through hole in the thickness direction. The detachable connection structure includes a connecting pipe 22, a first bolt 21, and a second bolt 22. The connecting pipe 22 has a threaded inner circumference and is installed in the second through hole of the mounting part of the first and second semi-float bodies. The first bolt 21 is installed in the mounting groove of the first semi-float body and is fixed in the connecting pipe 22 in the second through hole by means of threaded connection, and the bottom surface of the nut of the first bolt 21 abuts against the wall surface of the mounting part of the first semi-float body 1. The second bolt 21 is installed in the mounting groove of the second semi-float body and is fixed in the connecting pipe 22 in the second through hole by means of threaded connection, and the bottom surface of the nut of the second bolt 21 abuts against the wall surface of the mounting part of the second semi-float body 1.

[0086] In one embodiment, at least two sets of auxiliary pontoons 4 are provided on each cross brace 8. One set of auxiliary pontoons 4 is positioned on the cross brace 8 close to one of the side pontoons 15 connected to both ends of the cross brace 8, and the other set of auxiliary pontoons 4 is positioned on the cross brace 8 close to the other side pontoon 15 connected to both ends of the cross brace 8. Each set of auxiliary pontoons 4 includes at least one auxiliary pontoon 4. Preferably, each set of auxiliary pontoons 4 includes at least two auxiliary pontoons 4, and the auxiliary pontoons 4 in the set are arranged in a row along the axial direction of the cross brace 8.

[0087] In one instance, such as Figure 5-6 As shown, a method for transporting a floating offshore wind power generation system includes: installing a floating tension leg wind turbine platform foundation 9 on a semi-submersible barge 10, without loading ballast water into the central buoy and side buoys 15; installing auxiliary buoys 4 onto the cross braces 8 of the floating tension leg wind turbine platform foundation 9, adjusting the ballast water capacity in the auxiliary buoys 4 to ensure the floating tension leg wind turbine platform foundation 9 is stably positioned on the semi-submersible barge 10; towing the floating tension leg wind turbine platform foundation 9 to the wind turbine installation dock via the semi-submersible barge 10; and installing the wind turbine 12 on the floating tension leg wind turbine platform 9. On the foundation 9 of the wind turbine platform; adjust the ballast water capacity in the auxiliary buoy 4 to make the floating offshore wind power generation system stably set on the semi-submersible barge 10 and tow it to the installation area; wherein, at least two sets of auxiliary buoys 4 are set on each cross brace 8, one set of auxiliary buoys 4 is set on the cross brace 8 close to one of the side buoys 15 connected at both ends of the cross brace 8, and the other set of auxiliary buoys 4 is set on the cross brace 8 close to the other side buoy 15 connected at both ends of the cross brace 8; wherein, one set of auxiliary buoys 4 includes at least one auxiliary buoy 4.

[0088] In one instance, such as Figure 7 As shown, the method for installing a floating offshore wind power generation system in the sea includes: connecting the tension shank 13 to the suction anchor 14 set on the seabed; filling ballast water into the central buoy and / or side buoys 15 to submerge the platform to a predetermined water depth; installing the tension shank 13 at the lower end of the side buoys 15 of the floating tension leg wind turbine platform foundation 9; adjusting the ballast water volume of the central buoy and / or side buoys 15 so that the pretension force of the tension shank basically reaches the set value; and adjusting the ballast water volume of the auxiliary buoy 4 so that the pretension force of the tension shank reaches the set value.

[0089] In one example, a maintenance method for a floating offshore wind power system is described, where damage to the side buoy 15 leads to a change in the ballast water volume within the side buoy. This involves first adjusting the ballast water volume in the auxiliary buoy 4 installed on the cross brace 8 connected to the damaged side buoy, and / or adjusting the ballast water volume in the auxiliary buoy 4 installed on other cross braces 8, in order to stabilize the floating offshore wind power system.

[0090] The following details the methods for transporting, installing, and maintaining tension leg floating wind turbines, which may include the following steps:

[0091] The floating tension leg wind turbine platform foundation 9 is assembled on land, hoisted onto a semi-submersible barge, and towed to the wind turbine installation dock. A suitable number of detachable small auxiliary pontoons 4 are installed on the platform, and ballast water is pumped into the auxiliary pontoons 4 using external ballast pumps to ballast the platform, lowering its center of gravity and thus improving its stability on the ship. Since the auxiliary pontoons 4 will also play a role in installation and maintenance, they are not temporary additions and can be retained indefinitely.

[0092] After towing the floating tension leg wind turbine platform foundation 9 to the wind turbine installation wharf, the superstructure (blades, nacelle, tower) was hoisted to the lower floating tension leg wind turbine platform foundation 9 to complete the installation of the overall upper structure of the wind turbine. The number of detachable pontoons and the ballast water volume were then adjusted to ensure the stability of the platform, and the entire structure was towed to the project installation area.

[0093] After towing the entire wind turbine to the project area, the tension tendon 13 was installed. First, the end of the tension tendon 13 furthest from the platform was connected to a pre-drilled suction anchor on the seabed. Ballast water was pumped into the platform's buoys to submerge the platform to the predetermined draft. Once the platform reached the designated position, it was connected to the other end of the tension tendon 13. Then, the lengths of each tendon were adjusted. The tension tendon 13 was pre-tensioned by first adjusting the ballast water volume of the platform buoys (center buoy and side buoys 15), and then adjusting the ballast water volume of the detachable auxiliary buoy 4. This initial adjustment with a large ballast water volume on the platform buoys brought the tension tendon 13 to near the required range. Further fine-tuning using the auxiliary buoy 4 improved the accuracy of the pre-tension adjustment.

[0094] Furthermore, the foundation 9 of this floating tension leg wind turbine platform has a relatively small draft, relying primarily on the lower tension tendons to constrain the platform's six degrees of freedom of motion. Therefore, in unforeseen circumstances (such as impacts from ships, ice floes, or marine life), some compartments may be damaged and flooded. This could lead to tendon loosening or even rupture, subsequently causing platform capsizing, cable breakage, and other failure risks, resulting in significant economic losses. In such situations, directly adjusting the ballast water volume of the central buoy and side buoys 15 is highly complex and involves numerous unstable factors. Instead, the ballast water volume in the auxiliary buoys installed on the cross braces 8 connected to the damaged side buoy can be adjusted first. If necessary, the ballast water volume in the auxiliary buoys installed on other cross braces 8 can also be adjusted. This allows more time for emergency repairs before the necessary adjustment of the water volume in the central buoy and side buoys 15 becomes required, contributing to the stability of the floating offshore wind power generation system.

[0095] In embodiments of this invention, at least two sets of auxiliary pontoons are provided on each cross brace 8. One set of auxiliary pontoons is positioned on the cross brace 8 close to one of the side pontoons 15 connected to both ends of the cross brace 8, and the other set of auxiliary pontoons is positioned on the cross brace 8 close to another side pontoon 15 connected to both ends of the cross brace 8. Each set of auxiliary pontoons includes at least one auxiliary pontoon. In other embodiments, a set of auxiliary pontoons includes at least two auxiliary pontoons, and the auxiliary pontoons in the set are arranged in a row along the axial direction of the cross brace 8. The ballast water volume of the side pontoons 15 can be adjusted nearby, which is equivalent to fine-tuning the water volume of the side pontoons 15.

[0096] The detachable small pontoon used in this invention is made of HDPE (high-density polyethylene), which has good rigidity and impact resistance, thus maintaining good stability in water. The pontoon adopts a two-piece splicing structure, splicing it onto the cross brace 8 of the floating tension leg blower platform foundation. Symmetrical mounting holes for connecting parts 2 are provided at the pontoon joints. Threaded connecting pipes 22 are then inserted into the mounting holes, and bolts 21 are used to connect and fix the connecting pipes 22 on both sides.

[0097] In the operation and maintenance of this utility model, if it is necessary to replace the floats, water can first be injected into the inlet and outlet holes 6 through an external water pump to adjust the water volume in the floats so that the buoyancy of each float is slightly higher than its weight. Then, the bolts 21 and connecting pipes 22 are removed to make the floats float up, completing the disassembly. In the same way, the floats are filled with water using an external water pump, and then the floats are lowered to the designated position with the help of manual labor or an underwater robot (ROV), fitted onto the cross brace 8, and fixed with the connecting piece 2, thus completing the replacement.

[0098] The design of this utility model, featuring a detachable small auxiliary pontoon 4, reduces the amount of steel used in platform pontoons. Even if a single small pontoon is damaged, it will not significantly affect the overall safety and normal operation of the platform. The detachable small pontoon 4 is installed on the cross brace 8 of the floating tension leg fan platform foundation. In actual construction, the installation position and number of pontoons can be adjusted according to the platform type, and the size of the pontoons can also be adjusted according to the actual situation.

[0099] This invention utilizes a detachable, small pontoon 4, which is integrally mounted on the cross brace 8 of the floating tension leg wind turbine platform foundation. This provides redundant buoyancy to the platform and reduces the steel consumption of the side pontoons 15, saving construction costs. Because the detachable small pontoons are mounted on the cross brace 8, they protect the cross brace 8 when impacted by foreign objects. In the event of a breach in the platform's side pontoons 15 due to a sudden situation, the ballast water volume inside the small pontoons can be adjusted to help maintain the platform's stability and prevent major failures such as capsizing. Furthermore, due to its HDPE material and small size, even partial damage will not affect the overall stability of the platform. Installation and replacement can be performed manually or using an underwater robot, resulting in low costs.

[0100] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0101] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0102] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0103] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0104] In this invention, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one" refers to one or more; "at least one of A and B," similar to "A and / or B," describes the relationship between related objects, indicating that three relationships can exist. For example, at least one of A and B can represent: A alone, A and B simultaneously, or B alone.

[0105] In this utility model, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0106] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A floating tension leg wind turbine platform foundation, characterized by, include Center buoy; Side floats; A cross brace, used to connect the two side buoys; Tension ribs, wherein the tension ribs are disposed at the lower end of the side floats; An auxiliary buoy is formed as a column with a first through hole along the axial direction, and the space between the curved surface of the first through hole wall and the outer surface of the column is a hollow accommodating space. The auxiliary buoy is mounted on the cross brace through a first through hole between two bottom surfaces, and the accommodating space of the auxiliary buoy is used for loading or unloading ballast water. The auxiliary buoy has a smaller displacement than the central buoy and the side buoys.

2. The floating tension leg platform wind turbine platform foundation of claim 1, wherein, The auxiliary buoy includes a semi-floating body, which includes a first semi-floating body and a second semi-floating body. The first semi-floating body and the second semi-floating body are detachably connected and formed into an auxiliary buoy through the detachable connection.

3. The floating tension leg platform wind turbine platform foundation of claim 2, wherein, The semi-floating body is formed into a semi-circular annular cylinder, including an outer semi-circular curved surface, an inner semi-circular curved surface, a bottom connecting surface, a side connecting surface, a hollow accommodating space between the outer and inner semi-circular curved surfaces, and a sealable water inlet provided on the bottom connecting surface.

4. The floating tension leg fan platform foundation according to claim 3, characterized in that, The outer side of the semi-floating body is provided with at least one mounting groove, and the side connecting surface of the semi-floating body is formed into a mounting part with a certain thickness in the direction of the mounting groove. The mounting part is provided with a second through hole in the thickness direction. Detachable connection structure, including A connecting pipe, the inner circumference of which is threaded, is disposed in the second through hole of the mounting portion of the first semi-float and the second semi-float; The first bolt is located in the mounting groove of the first semi-floating body and is fixed in the connecting pipe in the second through hole by means of threaded connection, and the bottom surface of the nut of the first bolt abuts against the wall surface of the mounting part of the first semi-floating body. The second bolt is located in the mounting groove of the second semi-float and is fixed in the connecting pipe in the second through hole by means of threaded connection, and the bottom surface of the nut of the second bolt abuts against the wall surface of the mounting part of the second semi-float.

5. The floating tension leg wind turbine platform foundation of claim 4, wherein, The nuts of the first bolt and / or the second bolt are fitted with protective caps.

6. The floating tension leg wind turbine platform foundation of claim 5, wherein, The protective cover is made of plastic and has a magnetic strip inside.

7. The floating tension leg wind turbine platform foundation according to any of claims 1-6, characterized in that, in, At least two sets of auxiliary buoys are provided on each of the cross braces. One set of auxiliary buoys is positioned on the cross brace close to one of the side buoys connected to both ends of the cross brace. The other set of auxiliary buoys is positioned on the cross brace close to another side buoy connected to both ends of the cross brace. Each set of auxiliary buoys includes at least one auxiliary buoy.

8. The floating tension leg wind turbine platform foundation of claim 7, wherein, A set of auxiliary buoys includes at least two auxiliary buoys, and the auxiliary buoys in the set are arranged in a row along the axial direction of the cross brace.

9. The floating tension leg wind turbine platform foundation according to any of claims 1-6, characterized in that, The side buoys include a first side buoy, a second side buoy, and a third side buoy; the cross braces include a first cross brace, a second cross brace, and a third cross brace. It also includes inner transverse braces, which include a first inner transverse brace, a second inner transverse brace, and a third inner transverse brace; Wherein, the first side buoy and the second side buoy are connected by the first cross brace, the second side buoy and the third side buoy are connected by the second cross brace, and the third side buoy and the first side buoy are connected by the third cross brace, so that the side buoy and the cross brace are assembled into an equilateral triangle; The central buoy is located at the center of the equilateral triangle; The central buoy is connected to the first side buoy via a first inner cross brace, to the second side buoy via a second inner cross brace, and to the third side buoy via a third inner cross brace.

10. The floating tension leg wind turbine platform foundation according to any of claims 1-6, characterized in that, The shell of the auxiliary pontoon is made of polyethylene material; the volume ratio of the side pontoon to the auxiliary pontoon is (30~50):1.

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