Detachable tension leg type offshore wind turbine generator foundation platform and construction method thereof

Abstract

The invention belongs to the field of marine engineering technology, a detachable tension leg type offshore wind turbine foundation platform and its construction method, and the technical scheme is: the foundation platform includes tension tendons, side buoys, a central buoy and a truss support structure, the side buoys include fixed buoys and detachable buoys, the upper end of the tension tendons is vertically fixed to the bottom of the fixed buoys, and the detachable buoys are composed of a detachable inner buoy and a detachable outer buoy; the detachable inner buoy and the detachable outer buoy are fixed around the tension tendons under the fixed buoys; the central buoy is connected to the fixed buoys in the side buoys through a truss support structure. The present invention adopts a combination of fixed buoys and detachable buoys to replace traditional buoys, which can effectively solve the construction and installation problems of the tension leg type offshore wind turbine foundation platform in shallow water areas, and can effectively increase the length of the tension tendons, enhance the foundation hydrodynamic performance, and help maintain the tension tendons during operation.

Description

Technical Field

[0001] The present invention relates to the technical field of marine engineering, and in particular to a detachable tension-leg offshore wind turbine generator foundation platform with towing self-stabilization and an integrated construction method thereof. Background Art

[0002] With the continuous development of marine wind energy resources in my country, offshore wind power has gradually moved from shallow water to deep water, and floating offshore wind power will become the mainstream of offshore wind energy resource development in the future. The tension leg offshore platform is one of the three major floating offshore platform types in the world. Most of the existing tension leg offshore platforms in the world are used in the offshore oil industry. For offshore oil platforms, the platform water depth can reach several thousand meters, and the platform mainly bears wind wave current loads and platform deadweight loads; and for the wind turbine foundation platform, in addition to bearing the above loads, it is also necessary to withstand the huge bending moment generated by the wind turbine. Combined with my country's marine environmental conditions and my country's offshore wind power construction planning areas, the water depth of deepwater areas where floating offshore wind power can be constructed is mostly in the range of 30m to 50m. The tension leg offshore wind power foundation has the best adaptability to offshore wind turbines, but the current international application of tension leg offshore wind turbine platforms is more than 100 meters deep. For my country's marine water depth conditions, there are currently no application examples of traditional tension leg foundation platforms. At the same time, for the construction and installation of floating offshore wind power, the floating structure is greatly affected by waves and currents, and the accuracy of offshore installation is difficult to control; and for the integrated construction and installation plan, it is extremely inconvenient to manufacture special installation ships for shipping and installation due to the limitation of port water depth and the weight of wind turbines together with the foundation platform. Summary of the invention

[0003] In order to solve the shortcomings of the prior art, the purpose of the present invention is to provide a detachable tension leg type offshore wind turbine foundation platform and its construction method. The present invention adopts a combination of fixed buoys and detachable buoys to replace traditional buoys, which can effectively solve the construction and installation problems of the tension leg type offshore wind turbine foundation platform in shallow water areas, and can effectively increase the length of the tension tendons and enhance the basic hydrodynamic performance; at the same time, it is helpful for the maintenance of the tension tendons during operation.

[0004] The technical solution of the present invention is as follows: the basic platform includes tension tendons, side buoys, a central buoy and a truss support structure, the side buoys include fixed buoys and detachable buoys, the upper ends of the tension tendons are vertically fixed to the bottom of the fixed buoys, the detachable buoys are composed of a detachable inner buoy and a detachable outer buoy; the detachable inner buoy and the detachable outer buoy are fixed around the tension tendons under the fixed buoy; the central buoy is connected to the fixed buoys in the side buoys through a truss support structure.

[0005] Based on the above technical features, the volume of the detachable outer buoy is smaller than that of the detachable inner buoy.

[0006] When designing the foundation platform of a tension-leg offshore wind turbine, the natural period of the foundation platform is a standard that needs to be considered. Generally speaking, the natural period of the foundation platform needs to avoid the period of 5 to 15s in the area where the wave energy is concentrated. Therefore, for the longitudinal and transverse sway of the tension-leg platform, its period needs to be away from 15s. The longitudinal and transverse sway periods of the foundation platform of the tension-leg offshore wind turbine are proportional to the square of the length of the tension tendons. It can be seen that increasing the length of the tension tendons can effectively increase the natural period of the foundation platform. In the above structure, since the side buoys are divided into two layers, the upper part is a fixed buoy and the lower part is a detachable buoy, the actual installation length of the tension tendons can be raised to the bottom of the fixed buoy, rather than the bottom of the entire side buoy, which can effectively increase the natural period of the foundation platform. In order to cooperate with the installation and daily maintenance of the tension tendons, the detachable buoys are composed of detachable inner buoys and detachable outer buoys. When the upper end of the tension tendon is fixedly installed, the removable inner buoy and the removable outer buoy can be installed from both sides of the tension tendon to form an integral removable buoy on the tension tendon. When the tension tendon needs to be inspected and replaced, only the removable outer buoy located outside the tension tendon can be removed to inspect and replace the tension tendon; after inspection and replacement, the removable outer buoy is returned to its original position. Since only a small number of buoys are temporarily removed, the buoyancy of the entire tension leg offshore wind turbine foundation platform is not greatly affected.

[0007] The first construction method of the detachable tension leg offshore wind turbine foundation platform is:

[0008] Step A: The central buoy is connected to the fixed buoys in the side buoys through a truss support structure, and a tension bar connection device is embedded in the bottom of the fixed buoy.

[0009] Step B: Install the detachable buoy including the detachable inner buoy and the detachable outer buoy under the fixed buoy, install the offshore wind turbine generator set on the central buoy, and transport it at sea; make the buoyancy generated by the self-weight of the detachable buoy, the central buoy, the fixed buoy, the offshore wind turbine generator set and the truss support structure meet the buoyancy requirements of the foundation platform during offshore transportation.

[0010] Step C: After transporting to the designated installation site, adjust the detachable buoys so that the buoyancy generated by the self-weight of the detachable buoys, the central buoys, the fixed buoys, the offshore wind turbine generator set and the truss support structure meets the buoyancy requirements of the foundation platform during normal operation; connect the upper part of the tension tendon to the tension tendon connection device in the fixed buoy; fix the adjusted detachable inner buoy and the detachable outer buoy around the tension tendon under the fixed buoy; anchor the lower part of the tension tendon to the seabed or the foundation for anchoring on the seabed.

[0011] The method of adjusting the detachable buoy includes adjusting the ballast water of the detachable inner buoy and / or the detachable outer buoy; or replacing the detachable inner buoy and the detachable outer buoy with suitable sizes. The adjustment method belongs to conventional technical means in the art.

[0012] The second construction method of the detachable tension leg offshore wind turbine foundation platform is:

[0013] Step A: The central buoy is connected to the fixed buoys in the side buoys through a truss support structure, and a tension bar connection device is embedded in the bottom of the fixed buoy.

[0014] Step B: Connect the temporary transport buoy to the fixed buoy, install the offshore wind turbine generator set on the central buoy, and transport it at sea; make the buoyancy generated by the self-weight of the temporary transport buoy, the central buoy, the fixed buoy, the offshore wind turbine generator set and the truss support structure meet the buoyancy requirements of the foundation platform during offshore transportation.

[0015] Step C: After transporting to the designated installation site, remove the temporary transport buoy, connect the upper part of the tendon to the tendon connection device in the fixed buoy; anchor the lower part of the tendon to the seabed or the foundation for anchoring on the seabed; fix the detachable inner buoy and the detachable outer buoy around the tendon under the fixed buoy; make the buoyancy generated by the self-weight of the detachable inner buoy and the detachable outer buoy, the central buoy, the fixed buoy, the offshore wind turbine generator set and the truss support structure meet the buoyancy requirements when the foundation platform is working normally.

[0016] Compared with the existing technology, the above construction method realizes integrated construction, ensures the precision requirements of offshore construction, and avoids the problem that the floating structure is greatly affected by waves and currents and difficult to install at sea.

[0017] The detachable buoys used in the transportation and installation process of the foundation platform in the first construction method can be flexibly adjusted to cope with the buoyancy changes of the entire foundation platform according to the draft requirements during the transportation and installation of the foundation platform and the allowable sea and wave conditions during transportation and installation or the sea and wave conditions during normal operation.

[0018] For example, the total buoyancy F of the foundation platform during transportation and installation can be calculated according to the actual situation of the project, that is, the buoyancy corresponding to the total displacement during transportation and installation. At this time, the buoyancy F1 of the detachable buoy = the total buoyancy F-the buoyancy F2 provided by the fixed buoy-the buoyancy F3 generated by the deadweight of the offshore wind turbine generator set and the truss support structure-the buoyancy F4 provided by the central buoy; the present invention can select the number of side buoys according to the configuration design. Now assume that there are N side buoys, and there are N corresponding detachable buoys; then the buoyancy required to be provided by each detachable side buoy is F1 / N; assuming that the volume ratio of each detachable inner buoy and each detachable outer buoy is x:1, then the buoyancy required to be provided by each detachable inner buoy is xF1 / [N(x+1)], and the buoyancy required to be provided by each detachable outer buoy is F1 / [N(x+1)]. The number and volume of detachable side buoys, and the volume ratio of each detachable inner buoy and each detachable outer buoy can be adjusted according to each actual project situation. The detachable side buoys can be used as buoys in the normal working state of the foundation platform, and can also be used as transport and installation buoys. The so-called transport and installation buoys are buoys temporarily used during the transportation and installation of the offshore wind turbine foundation platform. According to the actual situation, after the offshore wind turbine foundation platform is in place, the buoyancy can be increased or decreased by adjusting the ballast water of the detachable buoys or / and replacing detachable buoys of different volumes to meet the buoyancy required for the normal working of the offshore wind turbine foundation platform.

[0019] In the second construction method, a transport buoy is used during transportation. After being transported to the designated installation site, the transport buoy is removed and a detachable inner buoy and a detachable outer buoy in the working state are installed. The construction method is simple.

[0020] In the above technical solution, the buoyancy calculation of the detachable inner buoy and the detachable outer buoy when the base platform is in normal working condition is the same as the buoyancy calculation during transportation and installation. At this time, the total buoyancy F of the base platform is the design buoyancy in normal working condition.

[0021] The beneficial effects of the present invention are as follows: by designing a detachable buoy to adjust the buoyancy of the basic platform in different working states, the top of the tension tendon is connected to the bottom of the side buoy in the traditional structure, while the top of the tension tendon is connected to the fixed buoy in the present invention, which can effectively increase the length of the tension tendon. At the same time, the detachable inner buoy and the detachable outer buoy are fixed around the tension tendon under the fixed buoy, and are composed of an assembleable structure, which is convenient for tendon detection and replacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the main structure of the present invention.

[0023] Figure 2 It is a schematic top view of the structure of the present invention.

[0024] Figure 3 It is a schematic diagram of the side buoy structure of the present invention.

[0025] Figure 4 It is a schematic diagram of the detachable buoy structure of the present invention.

[0026] The component numbers in the figure are as follows:

[0027] 100 Tendon tension

[0028] 200 Side Float

[0029] 210 Detachable pontoon

[0030] 211 Removable inner buoy

[0031] 212 Removable outer pontoons

[0032] 220 Fixed buoy

[0033] 230 Tension bar connection device

[0034] 300 Truss Support Structure

[0035] 400 Center Float DETAILED DESCRIPTION

[0036] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0037] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0040] like Figure 1 and Figure 2 As shown, the foundation platform of the detachable tension leg offshore wind turbine generator set includes a tension tendon 100, a side buoy 200, a central buoy 400 and a truss support structure 300. The side buoy 200 includes a fixed buoy 220 and a detachable buoy 210. The upper end of the tension tendon 100 is vertically fixed to the bottom of the fixed buoy 220. Figure 3 As shown, the tension tendon connection device 230 is embedded into the bottom of the fixed buoy 220 and connected to the tension tendon 100 at the bottom.

[0041] like Figure 3 and Figure 4 As shown, the detachable buoy 210 is composed of a detachable inner buoy 211 and a detachable outer buoy 212; the detachable inner buoy 211 and the detachable outer buoy 212 are fixed below the fixed buoy 220 around the tension tendon 100; Figure 1 and Figure 2 As shown, the central buoy 400 is connected to the fixed buoys 220 in the side buoys 200 via a truss support structure 300 to form a stable support structure, and the upper part of the central buoy 400 is connected to the offshore wind turbine generator set.

[0042] like Figure 2 As shown, the truss support structure 300 connects four side pontoons 200 and the central pontoon 400. The number of side pontoons and the configuration of the truss support structure shown in the figure are only for illustration. In the specific implementation process, the number of side pontoons and the configuration of the truss support structure 300 can be selected according to the actual stress and hydrodynamic performance.

[0043] like Figure 4 As shown, the volume ratio of the detachable inner buoy 211 and the detachable outer buoy 212 can be determined according to the actual engineering situation, and the volume of the detachable outer buoy 212 is preferably smaller than the detachable inner buoy 211. When the tension tendon needs to be inspected or replaced, the detachable outer buoy 212 is removed to inspect and replace the tension tendon; after the inspection and replacement, the detachable outer buoy 212 is returned to its original position. The smaller volume of the detachable outer buoy 212 can be easily disassembled and returned to its original position, and at the same time, during the disassembly process, it will not greatly affect the buoyancy of the basic platform. Figure 4 The volume ratio of the detachable inner buoy 211 to the detachable outer buoy 212 of 3:1 is only for illustration, and the detachable inner buoy 211 and the detachable outer buoy 212 can be divided to adjust the buoyancy ratio according to actual conditions such as marine environmental conditions.

[0044] The construction method of the present invention is exemplified as follows:

[0045] Step A: The central buoy 400 is connected to the fixed buoy 220 via the truss support structure 300 , and the tension bar connection device 230 is embedded in the bottom of the fixed buoy 220 .

[0046] Step B: Install the detachable buoy 210 including the detachable inner buoy 211 and the detachable outer buoy 212 under the fixed buoy 220, and install the offshore wind turbine generator set on the central buoy for sea transportation; make the buoyancy generated by the self-weight of the detachable buoy 210, the central buoy 400, the fixed buoy 220, the offshore wind turbine generator set and the truss support structure 300 meet the buoyancy requirements of the basic platform during sea transportation.

[0047] Step C: After transporting to the designated installation site, adjust the detachable buoy 210 so that the buoyancy generated by the self-weight of the detachable buoy 210, the central buoy 400, the fixed buoy 220, the offshore wind turbine generator set and the truss support structure 300 meets the buoyancy requirement of the foundation platform during normal operation; connect the upper part of the tension tendon 100 to the tension tendon connection device in the fixed buoy 220; fix the adjusted detachable inner buoy 211 and the detachable outer buoy 212 around the tension tendon 100 under the fixed buoy 220; anchor the lower part of the tension tendon 100 to the seabed or the foundation for anchoring on the seabed.

[0048] The second construction method of the detachable tension leg offshore wind turbine foundation platform is:

[0049] Step A: The central buoy 400 is connected to the fixed buoy 220 through the truss support structure 300, and the tension bar connection device 230 is embedded in the bottom of the fixed buoy 220;

[0050] Step B: Connect the temporary transport buoy to the fixed buoy 220, install the offshore wind turbine generator set on the central buoy 400, and transport it at sea; make the buoyancy generated by the self-weight of the temporary transport buoy, the central buoy 400, the fixed buoy 220, the offshore wind turbine generator set and the truss support structure 300 meet the buoyancy requirements of the basic platform during offshore transportation.

[0051] Step C: After transporting to the designated installation site, remove the temporary transport buoy, connect the upper part of the tendon 100 to the tendon connection device 230 in the fixed buoy 220; anchor the lower part of the tendon 100 to the seabed or the foundation for anchoring on the seabed; install the detachable inner buoy 211 and the detachable outer buoy 212 around the tendon 100 and fix them under the fixed buoy 220; make the buoyancy generated by the self-weight of the detachable inner buoy 211 and the detachable outer buoy 212, the central buoy 400, the fixed buoy 220, the offshore wind turbine generator set and the truss support structure 300 meet the buoyancy requirements when the foundation platform is working normally.

[0052] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A detachable tension leg offshore wind turbine foundation platform, characterized in that: The base platform comprises a tension tendon (100), a side pontoon (200), a central pontoon (400) and a truss support structure (300), wherein the side pontoon (200) comprises a fixed pontoon (220) and a detachable pontoon (210), wherein the upper end of the tension tendon (100) is vertically fixed to the bottom of the fixed pontoon (220), and the tension tendon connecting device (230) is embedded in the bottom of the fixed pontoon (220) and connected to the lower tension tendon (100). ) is connected; the detachable buoy (210) is composed of a detachable inner buoy (211) and a detachable outer buoy (212); the detachable inner buoy (211) and the detachable outer buoy (212) are fixed below the fixed buoy (220) around the tension tendon (100); the central buoy (400) is connected to the fixed buoy (220) in the side buoy (200) via the truss support structure (300).

2. The detachable foundation platform of the tension leg offshore wind turbine generator set according to claim 1, characterized in that: The volume of the detachable outer buoy (212) is smaller than that of the detachable inner buoy (211).

3. The construction method of a detachable tension leg type offshore wind turbine foundation platform according to claim 1, characterized in that: Step A: the central buoy (400) is connected to the fixed buoy (220) in the side buoy (200) via the truss support structure (300), and a tension bar connection device (230) is embedded in the bottom of the fixed buoy (220); Step B: installing a detachable buoy (210) comprising the detachable inner buoy (211) and the detachable outer buoy (212) below the fixed buoy (220), and installing the offshore wind turbine generator set on the central buoy (400) for marine transportation; making the buoyancy generated by the self-weight of the detachable buoy (210), the central buoy (400), the fixed buoy (220), the offshore wind turbine generator set and the truss support structure (300) meet the buoyancy requirements of the base platform during marine transportation; Step C: After being transported to the designated installation site, the detachable buoy (210) is adjusted so that the buoyancy generated by the self-weight of the detachable buoy (210), the central buoy (400), the fixed buoy (220), the offshore wind turbine generator set and the truss support structure (300) meets the buoyancy requirement of the foundation platform during normal operation; the upper portion of the tension tendon (100) is connected to the tension tendon connection device (230) in the fixed buoy (220); the adjusted detachable inner buoy (211) and the detachable outer buoy (212) are fixed around the tension tendon (100) below the fixed buoy (220); and the lower portion of the tension tendon (100) is anchored to the seabed or to a foundation for anchoring on the seabed.

4. The construction method of a detachable tension leg type offshore wind turbine foundation platform according to claim 1, characterized in that: Step A: the central buoy (400) is connected to the fixed buoy (220) in the side buoy (200) via the truss support structure (300), and a tension bar connection device (230) is embedded in the bottom of the fixed buoy (220); Step B: connecting the temporary transport buoy to the fixed buoy (220), installing the offshore wind turbine generator set on the central buoy (400), and transporting the offshore wind turbine generator set at sea; making sure that the buoyancy generated by the self-weight of the temporary transport buoy, the central buoy (400), the fixed buoy (220), the offshore wind turbine generator set, and the truss support structure (300) meets the buoyancy requirements of the foundation platform during offshore transportation; Step C: After transporting to the designated installation site, the temporary transport buoy is unloaded, and the upper part of the tension tendon (100) is connected to the tension tendon connection device (230) in the fixed buoy (220); the lower part of the tension tendon (100) is anchored on the seabed or a foundation on the seabed for anchoring; the detachable inner buoy (211) and the detachable outer buoy (212) are fixed around the tension tendon (100) below the fixed buoy (220); the buoyancy generated by the self-weight of the detachable inner buoy (211), the detachable outer buoy (212), the central buoy (400), the fixed buoy (220), the offshore wind turbine generator set and the truss support structure (300) meets the buoyancy requirement of the basic platform when it is working normally.

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