KR102719402B1 - sturcture for floating type offshore wind power and method of constructing the same - Google Patents

Abstract

A floating offshore wind power generation structure is disclosed, characterized by comprising a box-shaped structure capable of maintaining the airtightness of an internal space, and a water inlet/outlet device capable of filling or draining water at the bottom of the internal space while an air layer exists at the top of the internal space. The structure may be formed by a wall capable of covering and sealing the internal space, and a reinforcing frame structure, typically a pillar and a beam, for supporting the space between the walls while crossing the internal space. In this case, the wall, the pillar, and the beam may be formed as an integral piece with a reinforced concrete structure.
According to the present invention, a floating offshore wind power generation structure can be manufactured at a relatively lower cost and easily installed compared to existing structures, thereby reducing the overall construction cost and effort of the floating offshore wind power generation facility.

Description

Structure for floating type offshore wind power and method of constructing the same

The present invention relates to a structure for offshore wind power generation, and more specifically, to a floating substructure for installing a wind turbine in a floating offshore wind power generation and a method for installing the same.

In relation to global environmental issues, power generation technologies using renewable energy that can replace power generation using fossil fuels are continuously being researched, developed, and commercialized, and the need for floating offshore wind power generation as one of the important renewable energy generation methods is increasing.

In addition, the importance of floating substructure technology is increasing for stable power generation operation in these floating offshore wind power plants. In other words, the production and installation of suitable floating substructures is an essential element for stable power generation operation in harsh marine environments.

To explain further, in general, for onshore wind power generation and fixed offshore wind power generation, there are difficulties in the site selection process, and the closer to land you get, the scarcer the available space becomes, and the sensitivity to environmental impacts increases.

In comparison, floating offshore wind power plants can be installed far out at sea, making site selection relatively easy, and with less turbulence caused by obstacles, the wind can be strong and maintain a constant wind speed. Based on this excellent wind quality, it is possible to secure a high utilization rate of wind power generators.

However, unlike other types of wind power generation, floating offshore wind power must support large loads while floating and remain stable in the easily changing marine environment, which increases the importance of floating substructures. These substructures can usually be classified into spar, semi-submersible, tension-leg-platform, and barge types depending on their shape. In the case of Hywind Scotland, an early floating offshore wind power project, a spar type with high stability was adopted, but since the cylinder was erected and installed using a crane, there were problems with water depth restrictions and high costs due to crane vessel rental. The tension-leg type also has high stability, but the installation cost is very high, which makes the overall cost relatively high. On the other hand, the barge type has low installation and manufacturing costs, but the stability is relatively low.

Meanwhile, the semi-submersible type has the advantage of being easy to install as it is less affected by the installation location and weather conditions, and thus many projects currently scheduled to be developed are adopting the semi-submersible type, as the cost burden can be reduced by developing the Tetraspar structure or by developing the TELWIND structure and using a tugboat to install it.

However, even in semi-submersible structures, since steel materials and welding construction are mainly used, the material and construction costs are still considerable, and since wind turbines are not usually installed in the center of the structure, there is a problem that it is not easy to stably balance construction and maintenance in various weather and marine environments.

Republic of Korea Patent Publication No. 10-2014-0058470 Republic of Korea Patent Publication No. 10-2014-0090018 Republic of Korea Patent Publication No. 10-2017-0037641

The present invention is intended to provide a floating offshore wind power generation structure and an installation method thereof, which are configured to be manufactured at a relatively low cost and easily installed compared to existing structures, and to improve upon the problems of the existing floating offshore wind power generation structures described above.

The purpose of the present invention is to provide a floating offshore wind power generation structure and installation method suitable for stably constructing and maintaining a floating offshore wind power generation facility.

In order to achieve the above object, the floating offshore wind power generation structure of the present invention is characterized by comprising a box-shaped structure capable of maintaining the airtightness of the internal space, and a water inlet/outlet device capable of filling or draining water at the bottom of the internal space while an air layer exists at the top of the internal space.

In the present invention, the structure may be formed by a wall that can cover and seal an internal space, and a reinforcing frame structure, typically a column and a beam, that crosses the internal space and supports the space between the walls.

In the present invention, an air intake device capable of supplying or extracting air to or from an internal space through a wall may be provided, and in this case, a water intake device capable of supplying or extracting water or seawater to or from an internal space through the wall may be in the form of a simple through hole or open pipe.

In the present invention, the wall, pillars, and beams may be made of a reinforced concrete structure, a steel-concrete structure, or a mixed structure thereof.

In the present invention, a conduit penetrating the floating structure can be installed in the central portion where the wind turbine tower is placed, and the wall forming the conduit can serve as a reinforcing column so that the floating structure can support the weight of the wind turbine including the wind turbine tower installed thereon, and communication lines, power lines, cables, etc. of the wind turbine can pass through the floating structure through this conduit and be connected to other equipment installed on the seabed or underwater.

In the present invention, a mooring structure for fixing the floating structure may be installed or connected to a part of the floating structure.

The installation method of the present invention is characterized by comprising the steps of manufacturing the floating offshore wind power generation structure of the present invention on land, the step of floating the structure on water and towing it to an installation location offshore, the step of mooring the structure by controlling the buoyancy of the structure, and the step of installing a wind turbine on the structure.

According to the present invention, a floating offshore wind power generation structure can be manufactured at a relatively lower cost and easily installed compared to existing structures, thereby reducing the overall construction cost and effort of the floating offshore wind power generation facility.

According to the present invention, a floating offshore wind power generation facility can be constructed and maintained more stably than before through a floating offshore wind power generation structure.

Figure 1 is a perspective front view schematically showing a state in which a floating offshore wind power generation structure according to one embodiment of the present invention is installed together with a mooring device and a wind turbine.
Figure 2 is a cross-sectional plan view showing the positions of the side wall, beam, and aerial beam and the joint in the cross-section cut by the horizontal plane passing through the line AA in the embodiment of Figure 1.
FIGS. 3 and 4 are front views conceptually illustrating a high water level state in which the internal space is filled with a relatively large amount of water and a low water level state in which the internal space is filled with a relatively small amount of water in another embodiment of a floating offshore wind power generation structure of the present invention.

The present invention will be described in more detail through specific examples with reference to the drawings below.

Fig. 1 shows a floating offshore wind power generation structure of this embodiment, which is installed together with a mooring device and a wind turbine. Fig. 2 shows the positions of a side wall and its inner side beams, aerial beams, and joints in a cross-section cut by a horizontal plane passing through line AA of Fig. 1.

Referring to these drawings, the present embodiment will be described. In this embodiment, a floating offshore wind power generation structure (100) is formed by having a rectangular parallelepiped wall, columns formed vertically to reinforce the wall from the inside to maintain an internal space surrounded by the wall, and beams and air beams formed horizontally.

The wall is composed of a lower wall (110), four side walls (120), and an upper wall (130), and a beam (112, 122, 132) is formed horizontally on the inner surface of each wall facing the interior space. A column (140) formed vertically is positioned between the beam (132) of the upper wall and the beam (112) of the lower wall, and a horizontally formed air beam (150) is positioned between the beams (122) of the inner surfaces of the side walls (120) facing each other. A joint (170) is installed at the part where the column (140) and the air beam (150) meet each other in space.

This structure composed of columns (140) and aerial beams (150) may look similar to a frame structure without a slab, a steel frame structure. Here, there is one joint (170) between the upper wall beam (132) and the lower wall beam (112), but the number of these joints (170) may increase to two or more depending on the size or thickness of the structure. Similarly, there are six joints (170) along the aerial beams (150) extending horizontally in a straight line between the opposing side walls (120), but the number of these joints (170) may also be a different number depending on the size or width of the structure.

Walls and beams, columns and skylights may all be formed as a single unit by pouring reinforced concrete, or each element may be formed and joined in different ways. For example, walls may have a reinforced concrete structure, while columns and skylights may have a steel-concrete structure in which concrete surrounds the steel frame, a steel-concrete structure in which concrete surrounds the outside of hollow square steel tubes, or a steel-concrete structure in which concrete is placed between two square steel tubes of different sizes.

Here, a base plate (180) is installed in the center of the upper wall (130) on which a wind turbine (200) tower is installed. A central conduit (190) is formed to penetrate the rectangular parallelepiped structure in the vertical direction to connect the upper wall (130) and the lower wall (110) below the base plate (180). The wall forming the central conduit (190) can serve as a kind of pillar in this structure, supporting the weight of the wind turbine placed thereon more stably and distributing the weight, and unlike this embodiment, it can also have a configuration in which it is connected to the aerial beams.

These floating offshore wind power generation structures are formed so that the entire internal space surrounded by walls (110, 120, 130) can be sealed from the outside, or at least so that the upper space filled with air and acting as an air pocket can be sealed from the outside, and an air intake device (410) is installed on the upper part of the structure to allow air to be filled into the upper space acting as an air pocket or to allow air in the upper space to be removed to the outside.

The lower space of the internal space of this structure is filled with water, and a water inlet device (420) is installed to fill the lower space of this structure with water or drain the water to the outside.

The air inlet device (410) or water inlet device (420) may be configured by having a pipe connecting the internal space of the structure and the external space, and a valve and a pump installed on the path of the pipe. It is preferable that the pump be driven in both directions to enable filling or removing air or water into the internal space.

Although not explicitly disclosed in the drawings, in some embodiments, the lower space within the structure is not sealed from the outside, and water may be naturally introduced or introduced through a connection port at the bottom of the structure without a separate water inlet/outlet device, and the buoyancy of the structure may be controlled by removing or filling air in the upper space through an air inlet/outlet device. In this case, it may be necessary to determine the locations of the air inlet/outlet device and the connection port so as to prevent air in the upper space from escaping to the outside through a path other than the air inlet/outlet device, such as the connection port in the estuary space, and to operate the air inlet/outlet device in accordance with such a design.

In addition, although not shown here, a management access device (not shown) such as a separate inspection door may be installed on the upper part of this structure to manage the internal space of this structure, and this management access device must be configured to prevent air in the upper space from escaping unintentionally.

Meanwhile, the structure is equipped with mooring facilities to prevent the structure from drifting in the sea and leaving a certain location range.

The mooring facility may be composed of an unillustrated submarine fixture, a floating fixture (310) coupled with the structure, and a fixing cable (320) that connects and couples the submarine fixture and the floating fixture (310). The floating fixture (310) is illustrated here as being installed in four pieces, one at each lower vertex of the rectangular solid structure, but may be installed in an appropriate number and location considering the overall size and weight of the structure, the mechanical durability and strength of the cables and fixtures, etc. Since such mooring facilities are already well known, further detailed description thereof will be omitted here.

And, although not shown here, the power generated from the wind turbine (200) must be connected to an adjacent power network via a wire cable connected to the wind turbine, and the power network may be a substation including an inverter installed on an adjacent offshore structure, and a ground power facility that receives the power converted by the substation via a submarine wire cable. Since power facilities such as wire cables and communication line cables are usually connected to surrounding facilities via the submarine, such cables must be arranged to extend from the wind turbine (200) to the submarine, and for this purpose, it is preferable to use the central conduit (190) at the bottom of the wind turbine (200) tower. That is, the structure and the wind turbine can be combined and installed so that separate mooring cables, communication line cables, and power cables pass through the central conduit (190).

Next, the manufacturing and installation (installation of a wind power generation facility) of the structure of the present invention having such a configuration will be described.

First, the structure is designed to have the size of the floating offshore wind power generation structure with air pockets according to the capacity of the wind turbine, and the structure of the internal reinforcement elements. In the above embodiment, vertical columns, horizontal beams, and air beams are simply installed in the internal space of the rectangular solid wall, and a joint is provided where the air beams and columns meet, but the specific shape of the box and the reinforcement structure for maintaining the internal space can utilize various structures known in existing architecture.

Also, from a material perspective, the above embodiment can utilize various materials and their combinations known in existing construction in addition to the conventional reinforced concrete structure.

In terms of manufacturing, the structure of the present invention can be manufactured generally on land, especially in a dock used for building ships. Depending on the material and method of manufacturing elements such as walls, columns, beams, aerial beams, and joints, the manufacturing of the structure can be similar to the method of manufacturing a reinforced concrete building when these elements are formed of reinforced concrete. For example, the structure can be manufactured by manufacturing a frame, distributing reinforcing bars within the frame, and filling the frame with reinforcing bars with concrete.

In addition, we will manufacture anchors for floating bodies required for mooring structures and also manufacture anchoring cables.

At this time, if it is possible to secure the mechanical strength of the sealing and connecting parts, it is also possible to manufacture this structure by manufacturing some parts as blocks and combining the blocks to manufacture the entire structure, just as when manufacturing a large ship, each part is manufactured as a block and these blocks are combined to manufacture it.

Once the concrete has been sufficiently cured, and auxiliary equipment such as water inlet and air inlet devices have been installed, and the structure has been constructed so that the interior space can be sealed, the structure is immersed in water by methods such as filling it with water from a dock, and the size and pressure of the air pocket at the top of the interior space are adjusted so that it floats on water.

After the box-shaped structure is towed to the installation location of the wind turbine with the valves of the water inlet and air inlet devices closed, the structure can be supported first by a marine crane or the like.

The degree to which the structure floats on water is determined by considering the sea conditions, surrounding environment, and allowed time to reduce the resistance to movement and maintain stability when moving the structure from the manufacturing site to the wind turbine installation site. When moving, the degree of floatation is usually adjusted so that most of it is exposed to the air and only a part is submerged under the water surface to reduce the resistance of water. The degree of floatation can be specifically adjusted by using a water inlet device and an air inlet device to ensure that the internal space has an appropriate ratio of water and air layers.

Figures 3 and 4 illustrate a method for controlling the ratio of water and air layers in the internal space of a structure through a conceptual diagram of a simple configuration.

Figure 3 shows a low water level state in which the ratio of the water layer to the air layer is relatively small, with air being injected into the internal space of a sealed structure using an air inlet device and water being removed to the outside through a water inlet device. In this case, the buoyancy of the structure is relatively large, and the portion of the structure exposed above the surrounding water surface becomes larger.

However, since water is an incompressible liquid and air is a compressible gas, even if the water is left as is and the amount of air injected is increased, the buoyancy will not increase and the structure will not rise further. Considering this, the water inlet device will be the main means of buoyancy control. Therefore, in the case of applying this concept to the extreme, the amount of air in the internal space can be kept constant, and the relative ratio of the volume of the water layer to the entire internal space and the buoyancy control accordingly can be achieved by only operating the water inlet device.

Figure 4 shows a high water level state in which water is injected from the outside into the internal space of a sealed structure through a water inlet device, and the ratio of the volume of the water layer to the volume of the air layer is relatively large. In this case, the buoyancy of the structure is relatively small, and the portion of the structure exposed above the surrounding water surface is also reduced.

Meanwhile, when the structure arrives at the installation site, water is injected into the internal space through the water inlet device and air is removed through the air inlet device to create a high water level similar to that in Figure 4, and the level of the upper surface wall of the structure is lowered to facilitate the installation of the wind turbine. Then, the wind turbine is connected to the mooring and upper surface wall.

At this time, the degree to which the structure floats on water can be adjusted according to the situation in order to increase the surrounding environment and convenience of construction at the time of mooring and wind turbine combination. For example, if the wind turbine weighs a lot, it is necessary to increase the size of the upper space filled with air in the internal space of the structure to increase buoyancy. Normally, wind turbines are not installed in a completed state unless they are small in scale, but rather part of the tower, wind blades, and power generation device are installed by being lifted upward by a crane in sequence. It is desirable to adjust the buoyancy at each stage.

In relation to mooring, one end of the anchoring cable is connected to a floating fixture to stably fix the structure to a fixed sea location, and the other end of the anchoring cable is connected to a seabed fixture. The seabed fixture is installed on a stable seabed structure such as a rock, so that the floating offshore wind power generation facility is stably located and stabilized in a certain area.

Once stabilized, the buoyancy of these structures can be adjusted not only to control the mooring conditions but also during the installation of facilities on top of the structure and during the power generation process, depending on the surrounding weather and sea conditions to increase stability or increase the efficiency of wind power generation.

The floating offshore wind power generation structures examined above have a simple structure and are constructed using simple and clear principles. They can be manufactured very economically using inexpensive concrete among various materials, which has the advantage of minimizing the construction cost of floating offshore wind power generation facilities.

In addition, since this structure can be manufactured in a stable onshore environment rather than at sea, it is easy to secure product reliability, and since it is a sealed box-shaped structure, the structure can be towed to the location where the wind turbine is installed while floating on the sea, which reduces the cost of transporting the structure.

In particular, this structure is in the shape of a rectangular box, and if it is manufactured with a low height compared to the area, it can be manufactured and maintained more stably, and it is easy to install a wind turbine tower on the flat and wide top surface of the box, and since the structure is simple and easy to construct, construction costs can be minimized.

In addition, as in one aspect of the present invention, if a central conduit is installed that penetrates vertically through the central portion of the floating box structure, i.e., below the wind tower installation portion, transmission and distribution cables, etc. connected from the wind turbine tower can be directly connected to the seabed.

In addition, since the seawater with the same specific gravity as the seawater at the location where the wind turbine is installed is filled inside the floating box structure, it can be more stable against wave flow.

Although the present invention has been described above through limited examples, these are merely illustrative examples to help understanding of the present invention, and the present invention is not limited to these specific examples.

Accordingly, anyone with ordinary knowledge in the field to which the invention pertains will be able to make various modifications or application examples based on the present invention, and such modifications or application examples naturally fall within the scope of the appended patent claims.

100: Floating offshore wind power generation structure 110: Lower wall
112, 122, 132: 120: Side wall
130: Top wall 140: Column
150: Aerial 170: Joint
180: Base plate 190: Central pipe
200: Wind turbine 310: Fixture for floating body
320: Fixed cable 410: Air inlet device
420: Water inlet device

Claims (6)

In floating offshore wind power generation structures,
A box-shaped structure having a wall surface that covers and seals the internal space so as to maintain the confidentiality of the internal space;
A reinforcing skeletal structure for supporting the above internal space;
A water inlet device configured to fill or drain water at the bottom of the internal space while keeping air trapped at the top of the internal space for buoyancy control; and
An air inlet device formed to fill air into the upper space that acts as an air pocket at the upper part of a structure formed to be sealed from the outside or to discharge air from the upper space to the outside;
The above reinforcing frame structure is composed of vertically formed columns and horizontally formed beams,
The above water inlet device is configured by a water inlet pipe connecting an external space and the internal space, and a valve and a pump installed on the path of the water inlet pipe.
A floating offshore wind power generation structure characterized in that the air intake device comprises an air intake pipe connecting the upper space and the outside, and a valve and a pump installed on the path of the air intake pipe. delete In paragraph 1,
A floating offshore wind power generation structure characterized in that a central conduit is formed at the center of the box-shaped structure on which a wind turbine is installed upward, penetrating the box-shaped structure upward and downward. delete In paragraph 1,
A floating offshore wind power generation structure characterized in that the above wall, the above pillar, and the above beam are formed integrally with a reinforced concrete structure. A method for installing a floating offshore wind power generation structure according to any one of clauses 1, 3 and 5,
Step of manufacturing the above floating offshore wind power generation structure on land,
A step of floating the above floating offshore wind power generation structure on water and towing it to the installation site (location) at sea.
A step of lowering the level of the upper wall of the floating offshore wind power generation structure to facilitate installation of a wind power generator by injecting water into the internal space through the water inlet device and removing air through the air inlet device.
A step of attaching the wind turbine to the upper surface wall,
A step for controlling buoyancy so that the floating offshore wind power generation structure can float by controlling the volume ratio occupied by the air layer in the internal space.
A method for installing a floating offshore wind power generation structure, comprising the steps of: attaching one end of a fixing cable to a floating fixture, attaching the other end to a seabed fixture, and installing the seabed fixture on a stable seabed structure to stably fix the floating offshore wind power generation structure to a predetermined seabed location.

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