Semi-submersible offshore wind turbine generator floating type foundation of outer inclined stand column structure

Abstract

The utility model provides a semi-submersible offshore wind turbine generator floating type foundation of an outer inclined stand column structure, which is of a steel structure and comprises a plurality of steel stand columns and a heaving cabin. The floating type foundation is characterized in that the multiple stand columns comprise the multiple inclined stand columns which are obliquely designed, the multiple inclined stand columns are outwards inclined stand columns and are arranged at the vertex positions of a polygon respectively, the multiple outwards inclined stand columns are designed to be outwards inclined downwards and inwards, and the outwards inclined stand columns are main sources of buoyancy and stability of the floating type foundation. The floating body has low requirements on construction sites, ships and installation machinery, and has excellent floating body stability.

Description

Technical Field

[0001] The utility model relates to a floating foundation of a semi-submersible offshore wind turbine with an external inclined column structure, which is suitable for the field of offshore wind power development and has a wide range of water depth application. Background Art

[0002] At present, the mainstream types of floating foundations for offshore wind turbines are single-column, semi-submersible and tension-leg. These classic floating foundations have been implemented in some floating wind power projects. The stability and restoring force of the single-column foundation mainly comes from its deep draft design, forming a tumbler feature. Its application scenario requires a water depth of no less than 100 meters; the restoring force of the semi-submersible foundation mainly comes from its large waterline surface area and moment of inertia. It has a small requirement for water depth, but the structural scale is large, and it has high requirements for its construction site, launching-hoisting-transportation ships and their equipment; the tension-leg foundation uses the least steel, but the pre-tension of the tension tendons is greatly affected by ocean currents and tides, is sensitive to high-frequency environmental loads, and is prone to ringing and fatigue, which is risky. Relatively speaking, semi-submersible foundations are more widely used in floating wind power at home and abroad.

[0003] At present, the columns of semi-submersible foundations are mainly arranged vertically. In order to obtain better stability, this type of floating body needs to increase the span between columns or increase the diameter of the columns. The former requires a very large construction ship during installation, which is costly and difficult to install; the latter will undoubtedly greatly increase the structural weight of the floating body, increase the project investment, and also greatly increase the wave load and current load of the floating body, making the design of the mooring system difficult. Utility Model Content

[0004] The purpose of this utility model is to provide a floating foundation for a semi-submersible offshore wind turbine with an external inclined column structure in response to the development needs of large floating offshore wind turbines. The foundation has low requirements for construction sites, ships and installation machinery, and has excellent floating stability. To this end, the utility model adopts the following technical solutions:

[0005] A floating foundation for a semi-submersible offshore wind turbine with an externally inclined column structure, wherein the floating foundation is a steel structure, comprising a plurality of steel columns and a heave compartment; the characteristic is that the plurality of columns comprise a plurality of inclined columns with an inclined design, the plurality of inclined columns are externally inclined columns, which are respectively arranged at the vertices of a polygon, the plurality of externally inclined columns are designed to be externally inclined downward and inward, and the externally inclined columns are the main source of buoyancy and stability of the floating foundation.

[0006] The outward inclined column design proposed in the utility model enables the structure to have a larger waterplane radius at the waterplane, while the waterplane line area does not increase additionally, so while the waterplane restoring moment is increased, the wave load suffered is not increased additionally. In addition, the outward inclined design enables the structure to have a large volume entering the water and a small volume leaving the water in transient response when the structure undergoes heave and pitch and roll motions, thus having better stability and motion performance than the upright design.

[0007] The outer facade of the outer inclined column forms a certain angle with the water surface, and the size of the angle can be determined according to the actual design. The cross section of the steel column can be round or square. For the convenience of construction, the square cross section should be equipped with rounded corners.

[0008] Furthermore, the regular polygon is a regular polygon, and the inclination angles of the multiple externally inclined columns are the same.

[0009] Furthermore, the interior of the inclined columns is hollow and divided into multiple watertight compartments; the heave compartment is divided, part of which is filled with water ballast or fixed ballast, and is provided with valves for pipelines to pump ballast water, the pipelines also constitute connecting pipelines between ballast compartments, and part of it is used as a pump room to place ballast water regulating pumps. Other compartments not filled with ballast can be used as functional rooms to place equipment such as anchor winches and electromechanical cabinets.

[0010] Furthermore, the floating foundation is provided with three columns. For the three-column design, the three columns are all outwardly inclined columns, which are arranged according to the three vertices of a triangle, and one of the columns is used to set up a wind turbine.

[0011] Furthermore, the columns also include a central column, which is located at the center of the polygon; the floating foundation is provided with more than four columns. For the four-column design, three of the columns will serve as external oblique columns and will be arranged according to the three vertices of a triangle; one of the columns is set at the centroid of the triangle and serves as the central column to place the wind turbine, adopting a vertical design.

[0012] Furthermore, the interior of the columns is hollow and can be divided into multiple watertight compartments according to design requirements. The watertight compartments can be used to fill water ballast or fixed ballast, and the compartments not filled with ballast can be used as functional rooms to place equipment; the bottom end of the column is connected to the heave tank, which has the function of providing buoyancy and ballast space, and the cross-section of the heave tank is larger than the cross-section of the column.

[0013] Furthermore, the floating foundation also includes an upper box beam, which connects the upper ends of the multiple columns together; the floating foundation also includes a bottom buoyancy tank, which connects the heave tanks arranged at the lower ends of the multiple outer inclined columns together.

[0014] Furthermore, the floating foundation also includes a tower base, which is arranged on the upper end of a column on which the tower is arranged, and the tower is connected to the tower base.

[0015] Furthermore, the floating foundation is provided with a mooring chain, which is connected to a column at the top of the polygon at one end and fixed to the seabed at the other end through a tensioning connection device. The tensioning connection device is installed on the column at the top of the polygon and has the functions of mooring chain storage, mooring chain tensioning and relaxing, and mooring chain tension monitoring.

[0016] Due to the adoption of the technical solution of the utility model, the utility model adopts the external inclined column floating body solution, the lower floating body has a small span, and the launching and installation work can be completed with a smaller construction ship, which greatly improves the construction efficiency; the second-order moment of the floating body at the waterline position is large, which can provide greater stability, and stability adjustment is easier to achieve. In addition, the utility model can change the floating state of the floating body through the combination of ballast water regulation and further combined with mooring chain tension regulation to achieve response control. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 An oblique side view of the four-column floating fan system of the utility model.

[0018] Figure 2 Front view of the four-column floating fan system of the utility model.

[0019] Figure 3 A side view of a four-column floating fan system of the utility model.

[0020] Figure 4 Schematic diagram of the four-column floating foundation of the utility model.

[0021] Figure 5 Schematic diagram of a four-column heave cabin of the utility model.

[0022] Figure 6 Schematic diagram of four-column compartments of the utility model.

[0023] Figure 7 An oblique side view of the three-column floating fan system of the utility model. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0025] like Figure 1-6 As shown, a floating foundation of an outward inclined four-column semi-submersible offshore wind turbine generator system includes: a plurality of columns, a heave tank 2, a bottom buoyancy tank 3, an upper box beam 4 and a tower base 5.

[0026] The columns are the main structure of the floating foundation, the main source of buoyancy and stability of the floating foundation, and provide a certain ballast space. The columns include outer inclined columns 11 and central columns 12. There are three outer inclined columns 11, which are arranged at the vertices of the regular triangle, and the central column 12 is at the center of the regular polygon. The central column 12 is vertically arranged. The multiple outer inclined columns 11 are designed to be downward and inwardly contracted. The facade forms a certain angle with the water surface. The size of the angle can be determined according to the actual design. The outer inclined columns of this embodiment are square cross-section chamfered corners. The vertical swing tank 2 and the bottom buoyancy tank 3 provide partial buoyancy and main ballast space. The outer inclined columns 11 and the central column 12 are also hollow closed structures. The upper box beam 4 connects the outer inclined columns 11 and the central column 12. A walkway is set on the top of the upper box beam 4, which is controlled by buoyancy to expose the sea level. The tower base 5 is welded to the top of the central column 12, and the top of the tower base 5 is butted against the bottom flange of the wind turbine tower. The reference numeral 100 is a tower, and a nacelle is installed on the top of the tower.

[0027] Therefore, in this embodiment, the floating foundation is designed with four columns, three outward inclined columns 11 are used as outer columns, arranged according to the three vertices of an equilateral triangle, and adopt an outward inclined design; another column is set at the center of the triangle, used as a central column to place the wind turbine, and does not adopt an outward inclined design. Among them, the inside of the columns are hollow, divided into multiple watertight compartments for filling water ballast and fixed ballast, and the watertight compartments not filled with ballast are used to place equipment such as anchor winches and electromechanical cabinets.

[0028] like Figure 5 The outer inclined column 11 is divided into multiple compartments, including empty compartments, ballast compartments, and equipment compartments according to actual needs and layout. Figure 6 As shown. A better option is that the equipment cabin is set in the top cabin of each column to facilitate the entry of later personnel for maintenance; the pump cabin is set in one of the four cabins divided by the bottom swing tank. The pump cabin is equipped with an electrically controlled watertight seabed valve 15, which is connected to the outside and pumps water through a water pump. There are well-arranged pipelines from the pump cabin to each ballast tank, which can form connecting water pipes between the ballast tanks to ensure that the pump cabin can pump water and fill water for all ballast tanks and transfer ballast water between two ballast tanks. When the pipeline passes through the bulkhead, it is watertightly blocked by the tank penetration. A better option is to set two ballast water regulating pumps in the pump cabin, one for use and one for backup.

[0029] As can be seen from the figure, the columns are divided into several layers according to their elevations, and each layer has multiple cabins. A better option is to divide each layer into 4 cabins, select a cabin in the same position on each layer as an empty cabin, arrange ladders and cabin doors, and achieve connectivity between the cabins on each layer, making it convenient for operation and maintenance personnel to enter from the top of the platform and reach each floor.

[0030] The bottom end of the outer inclined column 11 is connected to the heave tank 2, and the heave tanks 2 are connected through the bottom buoyancy tank 3, and the central column 12 is connected to the bottom buoyancy tank 3. The cross section of the heave tank 2 is larger than the cross section of the outer inclined column 11, which can provide a larger attached mass and viscous damping when the floating body swings, pitches and rolls, thereby reducing the movement cycle of the floating body and reducing the movement acceleration. The heave tank 2 is divided into multiple compartments, including a pump room and a ballast tank. The pump room is used to place pumps and other equipment, and has valves for pipelines to pump ballast water. The ballast tank 3 is used to fill ballast water and solid ballast.

[0031] An annular steel platform may be provided at the top of the central column 2 to be connected to the walkway provided on the top of the upper box beam 4 and to the door at the bottom of the tower, so as to realize the connection of the operation and maintenance channel between multiple columns.

[0032] like Figure 6 As shown, a liquid level monitoring device 9 is installed in each ballast tank to monitor the liquid level status in the ballast tank in real time and serve as monitoring feedback for the ballast water monitoring and control system.

[0033] The mooring chain 111 is connected to the floating body foundation at one end and fixed to the seabed at the other end through the tensioning connection device 112. The tensioning connection device 112 is installed on the outer inclined column 12 of the floating body foundation, and has the functions of mooring chain storage, mooring chain tensioning and relaxing, and mooring chain tension monitoring (a preferred option is to integrate the chain storage box, anchor windlass, tension monitoring meter and control motor).

[0034] like Figure 7 As shown in the figure, it is a three-column floating foundation solution of the utility model patent. Figure 1-6 Compared with the above-mentioned embodiment, it does not have a central column but only has an outer inclined column 11. The tower 100 is installed on one of the outer inclined columns 11. The upper box beam 4 is connected to the adjacent outer inclined columns 11. The bottom end of the outer inclined column 11 is connected to the heave tank 2. The adjacent heave tanks 2 are connected through the bottom buoyancy tank 3. The internal structure of the outer inclined column 11 is the same as that of the above-mentioned embodiment.

[0035] The above embodiment is only a preferred technical solution of the present invention. Those skilled in the art should understand that the technical solutions or parameters in the embodiments can be modified or replaced without departing from the principle and essence of the present invention, and all should be included in the protection scope of the present invention.

Claims

1. A floating foundation of a semi-submersible offshore wind turbine with an external inclined column structure, wherein the floating foundation is a steel structure, including a plurality of steel columns and a heave tank; characterized in that: The plurality of columns include a plurality of inclined columns of inclined design, wherein the plurality of inclined columns are externally inclined columns, which are respectively arranged at the vertices of the polygon, and the plurality of externally inclined columns are designed to be downwardly and inwardly inclined, and the externally inclined columns are the main source of buoyancy and stability of the floating foundation; The columns are steel columns with square sections and rounded corners. The floating foundation also includes an upper box beam, which connects the upper ends of the plurality of columns together; a walkway is arranged on the top of the upper box beam, and the walkway is exposed above the sea level.

2. A floating foundation for a semi-submersible offshore wind turbine with an external inclined column structure as claimed in claim 1, characterized in that: The interior of the inclined columns is hollow and divided into multiple watertight compartments; the heave compartments are divided, part of which is filled with water ballast or fixed ballast and is provided with valves for pipelines to pump ballast water. The pipelines also constitute connecting pipes between ballast tanks, and part of them is used as a pump room to place ballast water regulating pumps.

3. The floating foundation of a semi-submersible offshore wind turbine with an external inclined column structure according to claim 1, characterized in that: The floating foundation is provided with three columns. For the three-column design, the three columns are all outwardly inclined columns, which are arranged according to the three vertices of a triangle, and one of the columns is used to set up a wind turbine.

4. The floating foundation of a semi-submersible offshore wind turbine with an external inclined column structure according to claim 1, characterized in that: The columns also include a central column, which is located at the center of the polygon; the floating foundation is provided with more than four columns. For the four-column design, three of the columns will serve as outer oblique columns and be arranged according to the three vertices of the triangle; one of the columns is set at the centroid of the triangle and serves as the central column to place the wind turbine, adopting a vertical design.

5. The floating foundation of a semi-submersible offshore wind turbine with an external inclined column structure according to claim 1, characterized in that: The interior of the columns is hollow and can be divided into multiple watertight compartments according to design requirements. The watertight compartments can be used to fill water ballast or fixed ballast, and the compartments not filled with ballast can be used as functional rooms to place equipment. The bottom end of the column is connected to the heave tank, which has the function of providing buoyancy and ballast space, and the cross-section of the heave tank is larger than the cross-section of the column.

6. The floating foundation of a semi-submersible offshore wind turbine with an external inclined column structure according to claim 1, characterized in that: The floating foundation further comprises a bottom buoyancy tank, which connects together the heave tanks arranged at the lower ends of the plurality of outer inclined columns.

7. The floating foundation of a semi-submersible offshore wind turbine with an external inclined column structure according to claim 1, characterized in that: The floating foundation also includes a tower base, which is arranged at the upper end of a column on which the tower is arranged, and the tower is connected to the tower base.

8. The floating foundation of a semi-submersible offshore wind turbine with an external inclined column structure according to claim 1, characterized in that: The floating foundation is provided with a mooring chain, one end of the mooring chain is connected to the column at the top of the polygon through a tensioning connection device, and the other end is fixed to the seabed. The tensioning connection device is installed on the column at the top of the polygon, and has the functions of mooring chain storage, mooring chain tensioning and relaxing, and mooring chain tension monitoring.

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