Large floating tension leg offshore wind power system and method of transporting, installing and maintaining same

Abstract

Large floating tension leg type offshore wind power generation system and its transportation, installation and maintenance method belong to the field of offshore wind power, and at least two groups of auxiliary pontoons are arranged on each transverse support of the floating tension leg type wind turbine foundation, one group of the auxiliary pontouns is arranged on the transverse support close to one side pontoon connected to one end of the transverse support, and the other group of the auxiliary pontoons is arranged on the transverse support close to the other side pontoon connected to the other end of the transverse support, wherein one group of the auxiliary pontoons comprises at least one auxiliary pontoon, the present application can reduce the transportation and installation difficulty of the floating wind turbine, improve the installation precision, and the auxiliary pontoon is convenient to disassemble and can be quickly replaced during operation and maintenance, and has installation convenience.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of offshore wind power, and relates to a large floating tension leg type offshore wind power system and a method for transporting, installing and maintaining the same. BACKGROUND

[0002] With the continuous transformation and development of global energy structure, the development of offshore wind power resources has attracted much attention, and the deep sea is becoming more and more popular due to its rich wind resources and good power generation stability. At present, the floating wind power platforms suitable for deep water development mainly include semi-submersible platforms, spar platforms, barge platforms and tension leg platforms (TLP).

[0003] The tension leg platform is a semi-compliant and semi-rigid floating deep water platform, and its core feature is to anchor the platform main body to the seabed by using a steel cable in tension, which has a small motion response under the action of wind and waves. The tension leg platform has a small sea area and a small amount of steel, which greatly saves the development cost and is suitable for deep water operation. In recent years, the design and research and development of tension leg type floating wind turbines are more and more. The tension leg type floating wind turbine relies on the lower floating body to provide buoyancy for the overall structure (including the wind turbine, the tower and the support platform). The part of the buoyancy exceeding the self weight of the structure is balanced by the pre-tension generated by the tension tendon, and this pre-tension setting greatly guarantees the overall stability of the platform.

[0004] At present, the towing transportation of floating wind turbines mainly includes dry towing and wet towing: dry towing transportation needs to consider many factors and is suitable for long distance transportation; wet towing transportation is relatively slow and is more suitable for short distance transportation. For example, the platform transportation of the Provence Grand Large (PGL) project, the first floating wind power project using tension leg foundation in the world, adopts wet towing method. Due to the small water area of the tension leg platform, temporary ballast water tanks are usually added during wet towing to lower the center of gravity of the platform and enhance the overall stability of the structure on the ship.

[0005] When installing floating offshore wind power systems, one end of the tension tendon is connected to a suction anchor on the seabed, and the other end is connected to a side buoy. The draft of the wind turbine foundation is then adjusted to ensure the tension tendon reaches the predetermined tension requirement. However, the buoys for large platform projects have extremely large capacities, reaching 1600-2000 tons or even higher. Adjusting the ballast water volume to regulate the draft is difficult and precise, potentially leading to insufficient pretension of the tension tendon. Especially when installing in deep-sea areas, the structural installation is subject to very strict environmental conditions, which are unpredictable, making water volume adjustment for ultra-large capacity buoys even more challenging and operationally extremely difficult. Careless operation during installation can lead to accidents such as tendon rupture.

[0006] On the other hand, pontoons may be subject to sudden accidents such as impacts from ships, ice floes, or marine life, causing damage to the compartments 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 complex, difficult, and lack convenient transitional adjustment methods. Furthermore, special operations such as anchor towing can also damage the cross bracing. Summary of the Invention

[0007] To address the aforementioned issues, a floating offshore wind power generation system according to some embodiments of this application includes a wind turbine and a floating tension leg wind turbine foundation, wherein the floating tension leg wind turbine foundation supports the wind turbine; wherein the floating tension leg wind turbine foundation includes a central buoy, side buoys, cross braces, and auxiliary buoys.

[0008] The cross brace is used to connect the two side floats; the auxiliary float 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.

[0009] The auxiliary buoy is mounted on the cross brace through a first through hole between the two bottom surfaces. The accommodating space of the auxiliary buoy is used for loading or unloading ballast water. The displacement of the auxiliary buoy is less than that of the central buoy and the side buoys.

[0010] According to some embodiments of the floating offshore wind power generation system of this application, the floating tension leg wind turbine foundation further includes a tension tendon, one end of which is disposed at the lower end of the side buoy, and the other end is connected to a suction anchor.

[0011] According to some embodiments of the present application, the floating offshore wind power system, the floating tension leg wind turbine foundation further comprises a support column, an inner cross brace and an inclined brace, wherein the inner cross brace comprises a first inner cross brace, a second inner cross brace and a third inner cross brace; the inclined brace comprises a first inclined brace, a second inclined brace and a third inclined brace;

[0012] The side pontoons of the floating tension leg wind turbine foundation comprise a first side pontoon, a second side pontoon and a third side pontoon, and the cross braces comprise a first cross brace, a second cross brace and a third cross brace;

[0013] The first cross brace is connected between the first side pontoon and the second side pontoon, the second cross brace is connected between the second side pontoon and the third side pontoon, and the third cross brace is connected between the third side pontoon and the first side pontoon, so that the side pontoons and the cross braces are assembled into an equilateral triangle;

[0014] The center pontoon is arranged at the center of the equilateral triangle, and the support column is arranged on the center pontoon;

[0015] The center pontoon is connected to the first side pontoon through the first inner cross brace, connected to the second side pontoon through the second inner cross brace, and connected to the third side pontoon through the third inner cross brace;

[0016] The support column is connected to the first side pontoon through the first inclined brace, connected to the second side pontoon through the second inclined brace, and connected to the third side pontoon through the third inclined brace.

[0017] According to some embodiments of the present application, the auxiliary pontoon comprises a half-float, and the half-float comprises a first half-float and a second half-float, which are detachably connected to form the auxiliary pontoon.

[0018] According to some embodiments of the present application, the half-float is shaped as a semi-circular column, comprising an outer semi-circular surface, an inner semi-circular surface, a bottom connecting surface, a side connecting surface, a hollow accommodating space between the outer semi-circular surface and the inner semi-circular surface, and a sealable water inlet arranged on the bottom connecting surface;

[0019] The outer side surface of the half-float is provided with at least one mounting groove, and the side connecting surface of the half-float is shaped as a mounting portion with a certain thickness in the direction of the mounting groove, and the mounting portion is provided with a second through hole in the thickness direction;

[0020] The detachable connection structure comprises a connecting pipe, a first bolt and a second bolt; the inner periphery of the connecting pipe is provided with a thread, and is arranged in a second through hole of the mounting portion of the first half floating body and the second half floating body; the first bolt is fixed in the connecting pipe in the second through hole in a threaded connection manner from the mounting groove of the first half floating body, and the bottom surface of the nut of the first bolt abuts against the wall surface of the mounting portion of the first half floating body; the second bolt is fixed in the connecting pipe in the second through hole in a threaded connection manner from the mounting groove of the second half floating body, and the bottom surface of the nut of the second bolt abuts against the wall surface of the mounting portion of the second half floating body.

[0021] According to some embodiments of the present application, the floating offshore wind power system, at least two groups of the auxiliary pontoons are arranged on each of the cross struts, one group of the auxiliary pontoons is arranged close to one of the side pontoons connected to the two ends of the cross strut, and another group of the auxiliary pontoons is arranged close to the other side pontoon connected to the two ends of the cross strut.

[0022] According to some embodiments of the present application, the floating offshore wind power system, one group of the auxiliary pontoons comprises at least two auxiliary pontoons, and the auxiliary pontoons in the group are arranged in a row in the axial direction of the cross strut.

[0023] According to some embodiments of the present application, the transportation method of the floating offshore wind power system comprises

[0024] The floating tension leg platform foundation is installed on the semi-submersible barge, and the central pontoon and the side pontoons are not loaded with ballast water.

[0025] The auxiliary pontoons are installed on the cross struts of the floating tension leg platform foundation, and the capacity of the ballast water in the auxiliary pontoons is adjusted to stably arrange the floating tension leg platform foundation on the semi-submersible barge.

[0026] The floating tension leg platform foundation is towed to the wind turbine installation wharf by the semi-submersible barge.

[0027] The wind turbine is installed on the floating tension leg platform foundation.

[0028] The capacity of the ballast water in the auxiliary pontoons is adjusted to stably arrange the floating offshore wind power system on the semi-submersible barge, and the floating offshore wind power system is towed to the installation sea area.

[0029] According to some embodiments of the present application, the floating offshore wind power system, at least two groups of the auxiliary pontoons are arranged on each of the cross struts, one group of the auxiliary pontoons is arranged close to one of the side pontoons connected to the two ends of the cross strut, and another group of the auxiliary pontoons is arranged close to the other side pontoon connected to the two ends of the cross strut.

[0030] Among them, one set of the auxiliary buoy includes at least one of the auxiliary buoy.

[0031] The sea installation method of the floating offshore wind power system according to some embodiments of the present application comprises

[0032] Connecting the tension tendon with the suction anchor arranged on the seabed;

[0033] Filling the center buoy and / or the side buoy with ballast water, so that the platform is submerged to a predetermined water depth;

[0034] Installing the tension tendon at the lower end of the side buoy of the floating tension leg wind turbine foundation;

[0035] Adjusting the amount of ballast water in the center buoy and / or the side buoy, so that the pre-tension of the tension tendon substantially reaches the set value;

[0036] Adjusting the amount of ballast water in the auxiliary buoy, so that the pre-tension of the tension tendon reaches the set value.

[0037] The maintenance method of the floating offshore wind power system according to some embodiments of the present application is characterized in that, when the side buoy is damaged and the amount of ballast water in the side buoy changes, the amount of ballast water in the auxiliary buoy installed on the cross brace connected to the damaged side buoy is adjusted first, and / or the amount of ballast water in the auxiliary buoy installed on other cross braces is adjusted, so as to stabilize the floating offshore wind power system.

[0038] Advantages:

[0039] The present application can provide redundant buoyancy for the platform by arranging the auxiliary buoy, reduce the demand for buoyancy provided by the platform buoy (center buoy, side buoy), and reduce the volume of the platform buoy to a certain extent, but the platform can basically maintain the original buoyancy. Reducing the volume of the platform buoy can reduce the amount of steel used and save costs. In addition, the auxiliary buoy can be made of lightweight materials such as polyethylene, which is equivalent to replacing steel materials with lightweight materials, which also helps to reduce the amount of steel used and save costs.

[0040] Based on the above, compared with the large-capacity ballast water adjustment of the center buoy and the side buoy, the auxiliary buoy realizes small numerical ballast adjustment within a certain range, which is more precise in ballast adjustment, and can reduce the adjustment difficulty to a certain extent compared with the large-capacity ballast water adjustment of the center buoy and the side buoy.

[0041] Based on the above, the auxiliary buoy of the present application can realize stability adjustment of the floating tension leg wind turbine foundation on the semi-submersible barge during the transportation stage, and no longer needs to add a temporary ballast tank.

[0042] Based on the above, it can also have a precise adjustment effect on the pre-tension of the tension tendon during the installation stage.

[0043] Based on the above, in the maintenance phase, the transitional adjustment role can be played to avoid directly adjusting the super large capacity ballast water of the main and side pontoons in maintenance, and more repair time is obtained before necessary adjustment of the super large capacity ballast water.

[0044] Based on the above, in the platform operation cycle, the auxiliary pontoon also has a protection effect on the cross brace to reduce the damage to the cross brace caused by special operations such as towing anchors. Cross brace damage will cause great difficulty in repair, and the platform may also be unstable. The auxiliary pontoon has the protection effect on the cross brace due to its characteristics of being detachable, convenient to replace and lower cost, and can reduce the possibility of platform damage and instability.

[0045] Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following description, or can be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The present application implements a technical roadmap.

[0047] Figure 2 is a schematic diagram of the semi-floating body and its connecting piece structure of the present application.

[0048] Figure 3 is a schematic diagram of the overall structure of the floating body connecting piece.

[0049] Figure 4 is a schematic diagram of the overall structure of the floating body.

[0050] Figure 5 is a schematic diagram of the installation and transportation of the floating tension leg wind turbine foundation.

[0051] Figure 6 is a schematic diagram of the installation and transportation of the wind turbine and the floating tension leg wind turbine foundation.

[0052] Figure 7 is a schematic diagram of the installation of the tension leg floating wind turbine structure in place.

[0053] Figure 8 is a schematic diagram of the inside of the floating body.

[0054] Figure 9 is another schematic diagram of the overall structure of the floating body.

[0055] Reference signs:

[0056] 1. Semi-floating body;

[0057] 2. Connecting piece; 21. Bolt; 22. Connecting pipe;

[0058] 3. Protective cover; 31. Magnetic piece;

[0059] 4. Auxiliary floating body;

[0060] 5. hollow slot;

[0061] 6. water inlet and outlet hole;

[0062] 7. air inlet and outlet hole;

[0063] 8. cross brace;

[0064] 9. floating tension leg platform wind turbine foundation;

[0065] 10. semi-submersible barge;

[0066] 11. tug;

[0067] 12. upper wind turbine;

[0068] 13. tension tendon;

[0069] 14. suction anchor;

[0070] 15. side buoy. DETAILED DESCRIPTION

[0071] Embodiments of the present application will be described in detail below with reference to the attached drawings, in which examples of embodiments are shown in the drawings, wherein the same or similar reference numbers represent the same or similar elements or elements having the same or similar functions throughout.

[0072] Currently, the towing transportation of floating wind turbines mainly adopts two modes: dry towing and wet towing. Dry towing requires more factors to be considered and is suitable for long-distance transportation. Wet towing is relatively slow and is more suitable for short-distance transportation. For example, the platform transportation of the Provence Grand Large (PGL) project, the first floating wind power project in the world using a tension leg platform, adopts wet towing. Because the floating tension leg platform wind turbine foundation has a small water area, temporary ballast tanks are usually added during wet towing to lower the platform's center of gravity and enhance the overall stability of the structure on the ship.

[0073] The floating tension leg wind turbine foundation is a semi-compliant, semi-rigid floating deepwater platform, and its core feature is to anchor the platform body to the seabed by using a steel cable in tension, which has a small movement response under the action of wind and wave, and the floating tension leg wind turbine foundation occupies a small sea area and uses less steel, greatly saving the development cost, and is suitable for deepwater operation. In recent years, the design and research and development of the tension leg type floating wind turbine are more and more. The tension leg type floating wind turbine relies on the lower floating body to provide buoyancy for the overall structure (including the wind turbine generator, the tower and the support platform). The part of the buoyancy exceeding the self weight of the structure is balanced by the pretension generated by the tension tendon. This pretension setting greatly guarantees the overall stability of the platform. When installing the floating offshore wind power system in the sea area, one end of the tension tendon is connected with the suction anchor arranged on the seabed, and then the other end of the tension tendon is connected with the side floatation tank. The draft of the wind turbine foundation is adjusted, so that the tension tendon reaches the predetermined tension requirement. However, the floatation tank capacity of the large platform project is very large, which can reach 1600-2000 tons, or even higher. The water quantity adjustment of the ballast water for adjusting the draft is difficult to adjust accurately, which may cause the pretension of the tension tendon to fail to meet the accuracy requirement. Especially when installing in the deep sea area, the installation of the structure has very strict requirements on the environmental conditions, and the environmental conditions during installation are uncertain, so it is more difficult to adjust the water quantity of the large-capacity floatation tank, and the operation difficulty is extremely large. Once the operation is not careful during installation, accidents such as tendon rupture may occur.

[0074] The floatation tank may suffer from sudden accidents such as ship collision, ice floe collision or marine organism collision, which may cause cabin damage, and further may cause overall failure or even damage of the structure, such as damage of the side floatation tank, which may cause water leakage or water inflow, and may cause instability of the platform. During the repair, the stability needs to be adjusted, and usually the ballast water quantity of the floatation tank is adjusted. As described above, due to the large capacity of the floatation tank, the adjustment complexity is high, and it is difficult to adjust, and there is a lack of more convenient transitional adjustment means. In addition, special operations such as anchor dragging may also cause damage to the cross brace.

[0075] Figure 1 It is an implementation roadmap for the transportation, installation and operation and maintenance of the floating tension leg wind turbine foundation. The present application sets a detachable small floatation tank, i.e. an auxiliary floatation tank 4, which is entirely sleeved on the cross brace 8 of the floating tension leg wind turbine foundation. The platform is ballasted by pumping ballast water into the auxiliary floatation tank during the installation and transportation of the floating platform and the upper wind turbine, so as to improve the overall stability of the structure. When installing the tension tendon 13, the ballast water quantity of the platform side floatation tank 15 and the small floatation tank is adjusted, so as to more finely control the lifting and adjustment of the platform and adjust the pretension, and simplify the installation difficulty of the tension tendon 13. In the operation and maintenance process, the small floatation tank can provide redundant buoyancy for the overall platform, and at the same time, due to its small size and distribution on the cross brace 8, even if part of it is damaged, it will not affect the overall stability of the platform, and it can be installed and replaced by artificial or underwater robots.

[0076] The floating tension leg wind turbine foundation of one embodiment of the present application comprises a central pontoon, side pontoons 15, cross braces 8, tension tendons 13, and auxiliary pontoons 4. The cross braces 8 are used to connect two side pontoons; the tension tendons 13 are arranged at the lower end of the side pontoons 15; and the auxiliary pontoons 4 are shaped as cylinders with first through holes arranged in the axial direction, and the space between the hole wall curved surface of the first through hole and the outer side surface of the cylinder is a hollow accommodating space. The auxiliary pontoons 4 are arranged on the cross braces 8 through the first through holes arranged between the two bottom surfaces, and the accommodating space of the auxiliary pontoons 4 is used to load or unload ballast water. The ballast water capacity of the auxiliary pontoons 4 is less than that of the central pontoon and the side pontoons 15.

[0077] The present application provides redundancy of buoyancy for the platform by arranging the detachable small pontoons which are entirely sleeved on the cross braces of the floating tension leg wind turbine foundation, so that the small pontoons can be made of light materials to reduce the steel consumption of the central pontoon and the side pontoons to a certain extent and save the cost under the condition of achieving the same buoyancy. Since the detachable small pontoons are sleeved on the cross braces, the cross braces can be protected. When the side pontoons of the platform are damaged due to an unexpected situation, the stability of the platform can be maintained by adjusting the amount of ballast water in the small pontoons, and the platform can be prevented from overturning and other major failure risks within a certain period of time. Since the small pontoons are made of HDPE material, the material is cheap and small in size, and even if part of the small pontoons is damaged, the overall stability of the platform will not be affected, and the small pontoons can be installed and replaced by manual or underwater robots, which is low in cost.

[0078] The auxiliary pontoons 4 comprise half floats 1, and the half floats 1 comprise first half floats and second half floats which are detachably connected to form the auxiliary pontoons 4. Preferably, the half floats 1 are shaped as semicircular cylindrical bodies comprising outer semicircular curved surfaces, inner semicircular curved surfaces, bottom connecting surfaces, side connecting surfaces, hollow accommodating spaces between the outer semicircular curved surfaces and the inner semicircular curved surfaces, and sealable water inlets arranged on the bottom connecting surfaces.

[0079] The side connecting surfaces of the half floats 1 are shaped as mounting portions with a certain thickness in the direction of the mounting grooves thereof, and the mounting portions are provided with second through holes in the thickness direction. The detachable connecting structure comprises connecting pipes 22 which are provided with threads in the inner periphery thereof and arranged in the second through holes of the mounting portions of the first half floats and the second half floats; first bolts 21 which are fixed in the connecting pipes 22 in the second through holes in a threaded connection manner from the mounting grooves of the first half floats, and the bottom surfaces of the nuts of the first bolts 21 abut against the wall surfaces of the mounting portions of the first half floats 1; and second bolts 21 which are fixed in the connecting pipes 22 in the second through holes in a threaded connection manner from the mounting grooves of the second half floats, and the bottom surfaces of the nuts of the second bolts 21 abut against the wall surfaces of the mounting portions of the second half floats 1.

[0080] The nut of the first bolt 21 and / or the second bolt 21 is provided with a protective cover 3. Preferably, the protective cover 3 is a plastic protective cover 3, and the protective cover 3 is provided with a magnetic piece 31.

[0081] Each cross strut 8 is provided with at least two groups of auxiliary floats 4, one group of auxiliary floats 4 is arranged on the cross strut 8 close to one side float 15 connected at one end of the cross strut 8, and the other group of auxiliary floats 4 is arranged on the cross strut 8 close to the other side float 15 connected at the other end of the cross strut 8, and one group of auxiliary floats 4 includes at least one auxiliary float 4. Preferably, one group of auxiliary floats 4 includes at least two auxiliary floats 4, and the auxiliary floats 4 in one group are arranged in a row in the axial direction of the cross strut 8.

[0082] The side float 15 includes a first side float, a second side float, and a third side float, and the cross strut 8 includes a first cross strut, a second cross strut, and a third cross strut; further including an inner cross strut, the inner cross strut includes a first inner cross strut, a second inner cross strut, and a third inner cross strut; wherein the first cross strut 8 is connected between the first side float and the second side float, the second cross strut 8 is connected between the second side float and the third side float, and the third cross strut 8 is connected between the third side float and the first side float, so that the side float 15 and the cross strut 8 are assembled into an equilateral triangle; wherein the center float is arranged at the center of the equilateral triangle; wherein the center float is connected to the first side float through the first inner cross strut, connected to the second side float through the second inner cross strut, and connected to the third side float through the third inner cross strut. Preferably, the shell of the auxiliary float 4 is a polyethylene shell; and the volume ratio of the side float 15 to the auxiliary float 4 is 30-50:1.

[0083] Another embodiment of the present application discloses a float, which can be referred to as an auxiliary float 4. The structure of the float is described with reference to Figure 2 , Figure 3 and Figure 4 The auxiliary float 4 includes a first half-float 1, a second half-float 1, a connecting piece 2, and a protective cover 3. The auxiliary float 4 is composed of two left-right symmetrical half-floats 1, and the auxiliary float 4 is provided with a hole slot for the connecting piece 2 to pass through, and the two floats are locked and fixed by the connecting piece 2, and the connecting piece 2 is distributed in two rows on the float, and there are eight in total. The two ends of the eight connecting pieces are provided with waterproof and corrosion-resistant protective covers 3.

[0084] With reference to Figure 2For the convenience of the installation and removal of the auxiliary float 4, the water inlet and outlet hole 6 and the air inlet and outlet hole 7 are arranged on one side of the float 1. During the installation, the water ballast pump is used to inject the water ballast into the water inlet and outlet hole 6, and at the same time, the air is discharged through the air inlet and outlet hole 7 to prevent the pressure in the float 1 from being too large. After the water ballast is completed, the external water ballast device is removed, and the water inlet and outlet hole 6 and the air inlet and outlet hole 7 are closed, so that the float 1 is sunk to the designated position and is sleeved on the cross brace 8, and then the connecting piece is installed, and the installation of the auxiliary float 4 is completed. The semi-float 1 is provided with a water hole which can be sealed by a cover or the like, and of course, a sealing structure such as a sealing gasket can also be added. When it is necessary to discharge the water in the auxiliary float 4, the water inlet and outlet hole 6 and the air inlet and outlet hole 7 are opened, and the water is discharged through the water inlet and outlet hole 6 by injecting the compressed air into the air inlet and outlet hole 7, and of course, other means for extracting water such as a pump can also be used. When it is necessary to inject water, the air inlet and outlet hole 7 can be closed in time, and the water can be injected through the water inlet and outlet hole 6 by using a pump or the like. The water inlet and outlet hole 6 and the air inlet and outlet hole 7 are arranged on each piece of the float, the water ballast is injected into the float through the external water pump to realize the water ballast function in the transportation process of the small float, and at the same time, the air inlet and outlet hole 7 is used to discharge the excess air in the float to ensure the balance of the pressure inside and outside the float. The water injection device in the float is a water ballast pump. The air inlet and outlet hole 7 is used to discharge the water in the float, and the water discharge device is a closed air compressor.

[0085] With reference to Figure 3 The connecting piece 2 is composed of two bolts 21 and a connecting pipe 22. The connecting pipe 22 is arranged in the auxiliary float 4, the connecting pipe 21 is internally provided with a thread, and the two ends are connected by the bolts 21, so that the auxiliary float 4 is locked and fixed. The side surface connecting surface of the semi-float is shaped into an installation part with a certain thickness in the direction of the installation groove of itself, the installation part is provided with a second through hole in the thickness direction, and is used for fixing the connecting pipe 22. It can be understood that the installation groove and the installation part are not communicated with the internal accommodating space. The bottom surface of the nut of one bolt abuts against the wall surface of the installation 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 installation part of the second semi-float 1, so that the two semi-floats are tightly fixed.

[0086] With reference to Figure 3 Because the bolt 21 is soaked in seawater for a long time, it is easy to be corroded and cause the loosening of the connection of the auxiliary float 4 and the damage of the overall structure. The protective cover 3 made of plastic material with certain corrosion resistance is arranged outside the bolt 21, the magnetic absorbing sheet 31 is arranged on the inner side of the protective cover 3, the protective cover 3 is tightly connected with the bolt 21 through the magnetic absorbing sheet 31, and the protective cover 3 plays a role of protecting the bolt 21, preventing rust and stabilizing the structure.

[0087] With reference to Figure 4 and Figure 5 , Figure 8 and Figure 9In order to enable the novel auxiliary buoy 4 to be sleeved on the cross brace 8 of the floating tension leg wind turbine foundation 9, a hollow groove 5, i.e., a first through hole, is arranged inside the auxiliary buoy 4, and 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 wind turbine foundation, so that the hollow groove 5 can be closely attached to the cross brace 8, and the stability of the whole structure is realized.

[0088] In an embodiment, the capacity of the side buoy 15 is 1600-2000 tons, and the capacity of the auxiliary buoy is 40-50 tons, and the volume ratio is about 40:1, and the specific size and capacity can be adjusted according to the actual structural design.

[0089] Referring to Figure 5 For the tension leg floating platform 9 built on land, i.e., the floating tension leg wind turbine foundation, it can be placed on the semi-submersible barge 10, transported to the wind turbine installation wharf by the tug 11 in a wet towing manner, and the upper wind turbine is installed. At the same time, a proper amount of auxiliary buoy 4 is installed on the cross brace 8 of the tension leg floating platform, and ballast water is injected into the auxiliary buoy 4 to lower the platform gravity center and improve the stability of the floating tension leg wind turbine foundation 9 during transportation.

[0090] Referring to Figure 6 After the installation wharf of the upper wind turbine 12 of the floating tension leg wind turbine foundation 9, the installation of the upper wind turbine 12 and the floating tension leg wind turbine foundation 9 is completed in a hoisting manner. At the same time, a proper amount of auxiliary buoy 4 is installed to improve the ballast and maintain the stability of the whole wind turbine and platform, and it is transported to the project sea area in a wet towing manner for installation of the lower structure.

[0091] Referring to Figure 6 and Figure 7 After the whole structure is transported to the project sea area, the auxiliary buoy 4 is first installed on the cross brace 8 of the floating tension leg wind turbine foundation 9, and then the platform 9 is driven away from the semi-submersible barge and connected to the tug 11 by a cable to maintain the stability of the whole structure. Then, the internal ballast pump of the side buoy 15 is used to inject water into the interior, so that the whole structure is lowered to the specified depth for installation of the tension tendon 13. The suction anchor 14 is pre-driven into the seabed, and then the tension tendon 13 is connected to the suction anchor 14 at one end and to the side buoy 15 at the other end. After the two ends of the tension tendon 13 are connected, the tendon is pre-tensioned. First, the internal ballast water of the three side buoys 15 can be adjusted to achieve the first pre-tensioning of the tendon, so that the pre-tensioning force of the tension tendon 13 basically reaches the set value. Then, according to the actual situation during installation, the water volume in the auxiliary buoy 4 on each cross brace 8 can be adjusted to further adjust the tension of each tension tendon 13, so that it reaches the predetermined tension, and the second pre-tensioning of the tendon is completed. During the two pre-tensioning processes, the length and pre-tensioning force of each tendon are always accurately controlled to ensure that the tendon is neither excessively tensioned nor relaxed. After the tendon is installed, the tug is driven away, and all temporary structures are removed, and the whole installation is completed.

[0092] Another embodiment of the present application discloses a floating offshore wind power system, comprising a wind turbine 12 and a floating tension leg wind turbine foundation 9 supporting the wind turbine 12; wherein the floating tension leg wind turbine foundation 9 comprises a central buoy, side buoys 15, cross braces 8 and auxiliary buoys 4; wherein the cross braces 8 are used to connect two side buoys; the auxiliary buoy 4 is shaped as a column with a first through hole arranged in the axial direction, and the space between the hole wall curved surface of the first through hole and the outer side surface of the column is a hollow accommodating space; wherein the auxiliary buoy 4 is arranged on the cross brace 8 through the first through hole opened between the two bottom surfaces, and the accommodating space of the auxiliary buoy 4 is used to load or unload ballast water, wherein the ballast water capacity of the auxiliary buoy 4 is less than that of the central buoy and the side buoy 15. In one scheme, the floating tension leg wind turbine foundation 9 further comprises a tension tendon 13 arranged at the lower end of the side buoy 15, one end of which is connected with the side buoy, and the other end is connected with a suction anchor at the seabed, and preferably the lower end of the side buoy is provided with a fairlead on the bottom surface or the side surface to install the tension tendon 13.

[0093] In one scheme, the floating tension leg wind turbine foundation 9 further comprises a support column, inner cross braces and inclined braces; wherein the inner cross braces comprise a first inner cross brace, a second inner cross brace and a third inner cross brace; the inclined braces comprise a first inclined brace, a second inclined brace and a third inclined brace; wherein the side buoy 15 of the floating tension leg wind turbine foundation 9 comprises a first side buoy, a second side buoy and a third side buoy, and the cross brace 8 comprises a first cross brace, a second cross brace and a third cross brace; wherein the first cross brace 8 is connected between the first side buoy and the second side buoy, the second cross brace 8 is connected between the second side buoy and the third side buoy, and the third cross brace 8 is connected between the third side buoy and 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 arranged at the center of the equilateral triangle, and the support column is arranged on the central buoy; wherein the central buoy is connected with the first side buoy through the first inner cross brace, connected with the second side buoy through the second inner cross brace, and connected with the third side buoy through the third inner cross brace; wherein the support column is connected with the first side buoy through the first inclined brace, connected with the second side buoy through the second inclined brace, and connected with the third side buoy through the third inclined brace.

[0094] In one aspect, the auxiliary pontoon 4 comprises a half-float 1, the half-float 1 comprises a first half-float and a second half-float, the first half-float and the second half-float are detachably connected to form the auxiliary pontoon 4. The half-float 1 is shaped as a semi-circular column, comprising an outer semi-circular surface, an inner semi-circular surface, a bottom connecting surface, a side connecting surface, a hollow accommodating space between the outer semi-circular surface and the inner semi-circular surface, and a sealable water inlet provided on the bottom connecting surface. The outer side of the half-float 1 is provided with at least one mounting slot, the side connecting surface of the half-float 1 is shaped as a mounting portion with a certain thickness in the direction of its own mounting slot, and the mounting portion is provided with a second through hole in the thickness direction. The detachable connection structure comprises a connecting pipe 22, a first bolt 21 and a second bolt 21. The inner periphery of the connecting pipe 22 is provided with threads and is arranged in the second through hole of the mounting portion of the first half-float and the second half-float. The first bolt 21 is fixed in the connecting pipe 22 in the second through hole by screw connection from the mounting slot of the first half-float, and the bottom surface of the nut of the first bolt 21 abuts against the wall surface of the mounting portion of the first half-float 1. The second bolt 21 is fixed in the connecting pipe 22 in the second through hole by screw connection from the mounting slot of the second half-float, and the bottom surface of the nut of the second bolt 21 abuts against the wall surface of the mounting portion of the second half-float 1.

[0095] In one aspect, at least two groups of auxiliary pontoons 4 are arranged on each cross strut 8, one group of auxiliary pontoons 4 is arranged on the cross strut 8 close to one side pontoon 15 connected to one end of the cross strut 8, and the other group of auxiliary pontoons 4 is arranged on the cross strut 8 close to the other side pontoon 15 connected to the other end of the cross strut 8. One group of auxiliary pontoons 4 comprises at least one auxiliary pontoon 4. Preferably, one group of auxiliary pontoons 4 comprises at least two auxiliary pontoons 4, and the auxiliary pontoons 4 in one group are arranged in a row in the axial direction of the cross strut 8.

[0096] In one example, as shown in FIG. 1, the cross strut 8 is arranged between the side pontoons 15, and the auxiliary pontoons 4 are arranged on the cross strut 8. Figure 5-6As shown, a method for transporting a floating offshore wind power generation system includes: installing a floating tension leg wind turbine 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 foundation 9, adjusting the ballast water capacity in the auxiliary buoys 4 to ensure the floating tension leg wind turbine foundation 9 is stably positioned on the semi-submersible barge 10; towing the floating tension leg wind turbine 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. On the foundation 9; 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.

[0097] 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 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.

[0098] 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.

[0099] The following details the methods for transporting, installing, and maintaining tension leg floating wind turbines, which may include the following steps:

[0100] The floating tension leg wind turbine 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.

[0101] After the floating tension leg wind turbine foundation 9 is towed to the wind turbine installation wharf, the upper structure (blade, cabin, tower drum) is connected with the lower floating tension leg wind turbine foundation 9 by hoisting, so as to realize the installation of the whole upper structure of the wind turbine. The number of the lower detachable floating buoys and the amount of ballast water are adjusted again, so as to realize the stability of the platform, and the platform is towed to the project installation sea area as a whole.

[0102] After the whole wind turbine is towed to the project sea area, the tension tendon 13 is installed. First, the end of the tension tendon 13 away from the platform is connected with the suction anchor previously driven into the seabed, the platform is submerged to the predetermined draft by pumping ballast water into the platform floating buoys, and after the platform reaches the specified position, the platform is connected with the other end of the tension tendon 13. Then, the length of each tendon is adjusted, and the tension tendon 13 is pre-tensioned by adjusting the ballast water amount of the platform floating buoys (central floating buoy, side floating buoy 15) first, and then adjusting the ballast water amount of the detachable auxiliary floating buoy 4. The first adjustment of the large ballast water amount of the platform floating buoys makes the adjustment requirement reach the vicinity of the required range, and then the auxiliary floating buoy 4 is used for fine adjustment, so as to improve the pre-tensioning force adjustment accuracy.

[0103] In addition, the draft line of the floating tension leg wind turbine foundation 9 is small, and the six-degree-of-freedom motion of the platform is mainly constrained by the lower tension tendons. Therefore, in the case of sudden situations (such as being hit by a ship, floating ice or marine organisms), part of the cabin may be damaged and flooded. This may cause the tendons to relax or even break, which may cause the platform to overturn, the cable to break and other failure risks, resulting in huge economic losses. In the above-mentioned situation, the ballast water amount of the central floating buoy and the side floating buoy 15 is directly adjusted, which has high operation complexity and many unstable factors. The ballast water amount of the auxiliary floating buoy installed on the cross brace 8 connected with the damaged side floating buoy can be adjusted first, and if necessary, the ballast water amount of the auxiliary floating buoy installed on other cross braces 8 can also be adjusted, so as to gain more repair time before the ballast water amount of the central floating buoy and the side floating buoy 15 must be adjusted, which is conducive to the stability of the floating offshore wind power system.

[0104] In the embodiments of the present application, at least two groups of auxiliary floating buoys are arranged on each cross brace 8, one group of auxiliary floating buoys is arranged on the cross brace 8 close to one side floating buoy 15 connected at one end of the cross brace 8, and the other group of auxiliary floating buoys is arranged on the cross brace 8 close to the other side floating buoy 15 connected at the other end of the cross brace 8. One group of auxiliary floating buoys includes at least one auxiliary floating buoy. In other schemes, one group of auxiliary floating buoys includes at least two auxiliary floating buoys, and the auxiliary floating buoys in one group are arranged in a row in the axial direction of the cross brace 8. The ballast water amount of the auxiliary floating buoy can be adjusted close to the side floating buoy 15, so as to correspond to the fine adjustment of the ballast water amount of the side floating buoy 15.

[0105] The detachable small buoy used in the application is made of HDPE (high density polyethylene) material, which has good rigidity and impact resistance, so it can maintain good stability in water. The buoy adopts a two-piece splicing structure, which is spliced on the cross brace 8 of the floating tension leg wind turbine foundation. Symmetrical mounting holes are provided on the connection of the buoy for the connection piece 2 to pass through, and then the threaded connecting pipe 22 is passed into the mounting hole, and the connecting pipe 22 is fixed by bolts 21 on both sides.

[0106] In the operation and maintenance process of the application, if it is necessary to replace the buoy, water can be injected into the water inlet and outlet hole 6 through an external water pump to adjust the water quantity in the buoy, so that the buoyancy of each buoy is slightly higher than the gravity, and then the bolts 21 and the connecting pipe 22 are removed, so that the buoy floats up and is disassembled. In the same way, the external water pump is used to fill the buoy with water, and then the buoy is lowered to the designated position by manual or underwater robot (ROV), and is sleeved on the cross brace 8, and the connecting piece 2 is installed and fixed, and finally the replacement is completed.

[0107] The design of the detachable small auxiliary buoy 4 of the application can reduce the steel consumption of the platform buoy, and even if a single small buoy is damaged, it will not have a great impact on the safety and normal operation of the platform as a whole. The installation position of the detachable small buoy 4 is on the cross brace 8 of the floating tension leg wind turbine foundation. In actual construction, the installation position and the number of the buoy can be adjusted according to the type of the platform, and the size of the buoy can also be adjusted according to the actual situation.

[0108] The application provides a kind of detachable small buoy 4, which is sleeved on the cross brace 8 of the floating tension leg wind turbine foundation, thereby providing redundant buoyancy to the platform, reducing the steel consumption of the side buoy 15 to a certain extent and saving the construction cost. Since the detachable small buoy is sleeved on the cross brace 8, it can protect the cross brace 8 when an external object hits the cross brace 8. When the platform side buoy 15 is damaged due to an emergency, the internal ballast water quantity of the small buoy can be adjusted to assist in maintaining the stability of the platform and prevent the platform from overturning and other major failure risks. At the same time, since it is made of HDPE material and has a small volume, even if it is partially damaged, it will not affect the overall stability of the platform, and it can be installed and replaced by manual or underwater robot, which costs less.

[0109] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements indicated thereby must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0110] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated thereby. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0111] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or in communication with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication or interaction relationship of two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0112] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or it can only mean that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or it can only mean that the horizontal height of the first feature is less than that of the second feature.

[0113] In the present application, the term "and / or", describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. The character " / " generally represents that the associated objects before and after it are in an "or" relationship. "At least one" means one or more; "at least one of A and B" is similar to "A and / or B", which describes the association relationship of the associated objects, which means that there can be three relationships, for example, at least one of A and B, which can represent the three cases of A alone, A and B together, and B alone.

[0114] In the present application, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0115] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacement or change according to the technical scheme and inventive concept of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A floating offshore wind power generation system, characterized in that, It includes a wind turbine and a floating tension leg wind turbine foundation, wherein the floating tension leg wind turbine foundation supports the wind turbine; wherein the floating tension leg wind turbine foundation includes a central pontoon, side pontoons, cross braces and auxiliary pontoons; The cross brace is used to connect the two side floats; the auxiliary float 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. The accommodating space of the auxiliary buoy is used for loading or unloading ballast water. The displacement of the auxiliary buoy is less than that of the central buoy and the side buoys. 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 are formed into an auxiliary buoy through the detachable connection. 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. 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. The detachable connection structure includes a connecting pipe, a first bolt, and a second bolt. The connecting pipe has a threaded inner circumference and is disposed in the second through hole of the mounting portion of the first and second semi-floats. The first bolt is disposed in the mounting groove of the first semi-float and is fixed to the connecting pipe in the second through hole by a threaded connection, with the bottom surface of the nut of the first bolt abutting against the wall surface of the mounting portion of the first semi-float. The second bolt is disposed in the mounting groove of the second semi-float and is fixed to the connecting pipe in the second through hole by a threaded connection, with the bottom surface of the nut of the second bolt abutting against the wall surface of the mounting portion of the second semi-float. Each of the cross braces is provided with at least two sets of auxiliary buoys, one set of auxiliary buoys on the cross brace is positioned close to one of the side buoys connected at both ends of the cross brace, and the other set of auxiliary buoys on the cross brace is positioned close to another side buoy connected at both ends of the cross brace, wherein one set of auxiliary buoys includes at least one auxiliary buoy.

2. The floating offshore wind power generation system according to claim 1, characterized in that, The floating tension leg fan foundation also includes a tension tendon, one end of which is located at the lower end of the side float, and the other end is connected to a suction anchor.

3. The floating offshore wind power generation system according to claim 1, characterized in that, The floating tension leg fan foundation also includes support columns, inner horizontal braces, and diagonal braces, wherein the inner horizontal braces include a first inner horizontal brace, a second inner horizontal brace, and a third inner horizontal brace; and the diagonal braces include a first diagonal brace, a second diagonal brace, and a third diagonal brace. The side floats of the floating tension leg fan foundation 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. 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, and the support column is located on the central buoy; 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. The support column is connected to the first side buoy via a first diagonal brace, to the second side buoy via a second diagonal brace, and to the third side buoy via a third diagonal brace.

4. The floating offshore wind power generation system according to claim 1, characterized in that, 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.

5. A method for transporting the floating offshore wind power generation system according to claim 1, characterized in that, include The foundation of the floating tension leg fan is installed on a semi-submersible barge, with no ballast water loaded in the center buoy and side buoys; Install auxiliary buoys on the cross braces of the floating tension leg fan foundation, and adjust the ballast water capacity in the auxiliary buoys to ensure that the floating tension leg fan foundation is stably placed on the semi-submersible barge. The floating tension leg wind turbine foundation was towed to the wind turbine installation dock by a semi-submersible barge. Install the fan on the foundation of the floating tension leg fan; Adjust the ballast water capacity in the auxiliary buoy to ensure the floating offshore wind power generation system is stably installed on the semi-submersible barge and towed to the installation area; Each of the cross braces is provided with at least two sets of auxiliary pontoons. 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 the other side pontoon connected to both ends of the cross brace. The group of auxiliary pontoons includes at least one of the auxiliary pontoons.

6. The method for installing the floating offshore wind power generation system according to claim 1 in the sea area, characterized in that, include The tension tendon is connected to a suction anchor set on the seabed; Ballast water is loaded into the center buoy and / or side buoys to submerge the platform to the predetermined water depth; Install the tension tendon at the lower end of the side float of the floating tension leg fan foundation; Adjust the ballast water volume of the center buoy and / or side buoys so that the pretension force of the tension tendon basically reaches the set value; Adjust the ballast water volume of the auxiliary buoy to bring the pretension of the tension tendon to the set value.

7. The maintenance method for the floating offshore wind power generation system according to claim 1, characterized in that, If the ballast water volume in a side buoy changes due to damage, the ballast water volume in the auxiliary buoys installed on the cross braces connected to the damaged side buoys should be adjusted first, and / or the ballast water volume in the auxiliary buoys installed on other cross braces should be adjusted to stabilize the floating offshore wind power generation system.

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