JP7473503B2 - How to assemble a floating wind turbine - Google Patents

Description

The present invention relates to a method for assembling a floating wind power generation facility.

Wind power generation is one of the renewable energies that aims to reduce greenhouse gas emissions. Wind power generation facilities are preferably installed in locations away from residential areas, as the noise and vibrations from wind turbines can affect the living environment. For this reason, wind power generation facilities are sometimes installed on the sea (on water).
On the other hand, when constructing a wind power generation facility in deep water, it takes a lot of time and effort to construct a foundation structure that will land on the bottom and to install piles on the bottom of the water. For this reason, a wind power generation facility may be constructed by erecting a tower on a floating structure moored on the water.
For example, Patent Document 1 discloses a floating wind power generation facility consisting of a float, a mooring line connected to the float, a tower erected on the float, and a nacelle and wind turbine blades installed at the top of the tower. The construction process of the floating wind power generation facility of Patent Document 1 is as follows. First, the float is towed sideways to a predetermined position, and then ballast water is poured into the float to erect the float. At this time, a wire extending from a balance adjustment float installed near the float is attached to the bottom of the float, and the wire is sent out as the float is erected. Once the float is erected, ballast material is poured into the bottom of the float and the float is moored with a mooring line. Then, a crane is used to fix the tower to the float in an erected state, and the nacelle and blades are installed at the top of the tower. At this time, the rotation of the float is controlled by sending out and rewinding the wire extending from the balance adjustment float.
However, skilled techniques are required to control the rotation of the float using wires. In addition, the rotation control using the balance adjustment float is performed after the float starts to rotate, and does not suppress the occurrence of rotation itself. Therefore, it is difficult to ensure stability when fixing the tower. Furthermore, the task of standing up a horizontal float is laborious and time-consuming.

JP 2012-201219 A

An object of the present invention is to propose a method for assembling a floating wind power facility that ensures the stability of a floating structure during construction, thereby improving workability.

The method for assembling a floating wind power generation facility of the present invention for solving the above problems includes a mooring step of mooring a floating structure at a predetermined position, a temporary fixing step of temporarily fixing a tower suspended by a crane in an upright state on the floating structure, and a tower self-supporting step of making the tower self-supporting on the floating structure. The floating structure is provided with ballast material for ensuring horizontality after the tower is installed, and a ballast water storage tank for storing ballast water for ensuring horizontality before the tower is installed, and in the tower self-supporting step, the ballast water previously stored in the ballast water storage tank is discharged and the tower is removed from the crane.
According to this floating wind power generation facility assembly method, the horizontality of the floating structure is ensured by the ballast material and the ballast water storage tank until the tower self-supporting process, so that the rotation of the floating structure is suppressed. Therefore, stability is ensured when erecting the tower. In addition, when the tower is made to stand on the floating structure, ballast water is discharged from the ballast water storage tank, and balance is ensured between the tower and the ballast material, so stability is also ensured during construction.

Here, it is preferable that the amount of ballast water stored in advance in the ballast water storage tank is an amount that causes an overturning moment acting on the floating structure on which the tower is installed to be equal to or greater than the overturning moment acting on the floating structure on which the tower is installed. In this way, the horizontality of the floating structure is ensured even if the overturning moment increases due to the attachment of the wind turbine body (nacelle, blades, etc.) to the tower.
In addition, during the wind turbine installation process in which the wind turbine main body (nacelle, blades, etc.) is attached to the tower, levelness is ensured by draining ballast water from the ballast water storage tank or increasing the amount of ballast material in parallel with the installation work of the wind turbine main body.

According to the method for assembling a floating wind power generation facility of the present invention, the stability of the floating structure during construction can be ensured, and as a result, construction workability can be improved.

1 is a side view showing an embodiment of the floating wind power generation facility according to the present invention. FIG. 1A is a schematic diagram showing the floating structure of the present embodiment, and FIG. 1B is a schematic diagram showing a conventional floating structure with a tower installed thereon. 2 is a flowchart of a method for assembling a floating wind power facility according to an embodiment of the present invention. FIG. 1 is a side view showing each step of the method for assembling a floating wind power generation facility, where (a) is a mooring step, (b) is a temporary fastening step, (c) is a tower self-supporting step, and (d) is a tower self-supporting step following (c). 10A and 10B are schematic diagrams showing a floating structure according to another embodiment, in which FIG.

In this embodiment, a floating wind power generation facility 1, which is a power generation facility provided on water, will be described. Fig. 1 shows the floating wind power generation facility 1 of this embodiment. The floating wind power generation facility 1 of this embodiment generates wind power while being moored on water, and as shown in Fig. 1, includes a floating structure 2, a tower 3 erected on the floating structure 2, and a wind turbine main body 4 provided at the top of the tower 3.
The floating structure 2 constitutes the foundation of the floating wind power generation facility 1. Fig. 2 shows an overview of the floating structure 2. As shown in Fig. 2, the floating structure 2 includes a first tank 5 provided at a position away from the installation position of the tower 3, and a second tank 6 provided in the vicinity of the installation position of the tower 3.

The tower 3 is a support for supporting the wind turbine body 4. The tower 3 is provided at a position eccentric to the center of the floating structure 2 (the amount of eccentricity of the tower 3 is e1). The tower 3 in this embodiment is provided on one end side (the left side in FIG. 2 ) of the center of the floating structure 2.
The wind turbine main body 4 is made up of blades 10, a nacelle 11, etc. (see FIG. 1). After the tower 3 is erected on the floating structure 2, the wind turbine main body 4 is installed at the top of the tower 3.

The first tank 5 is provided within the floating structure 2 and stores ballast material 7. In this embodiment, the first tank 5 is provided at the other end (the right end in FIG. 1 ) of the floating structure 2. The first tank 5 in this embodiment is provided at a position eccentricity e2 from the center of the floating structure 2. The first tank 5 is a hollow box-shaped member formed continuously in the width direction inside the floating structure 2. A ballast material inlet that communicates with the interior of the first tank 5 is formed on the upper surface of the floating structure 2 in correspondence with the position of the first tank 5.
When the tower 3 is installed on the floating structure 2, a first overturning moment M1 (=W1×e1) acts on the floating structure 2 due to the weight W1 of the tower 3, and if there is insufficient moment to counter this, the floating structure 2 will tilt (rotate) as shown in Fig. 2(b). Therefore, the capacity of the first tank 5 is set to a size capable of accommodating ballast material 7 of weight W2 that generates a second overturning moment M2 (=W2×e2) that counteracts the first overturning moment M1 acting on the floating structure 2 by installing the tower 3 and ensures horizontality.

The second tank 6 is a ballast water storage tank that stores ballast water 8, and is provided on the upper surface of the floating structure 2 as shown in Fig. 2(a). In this embodiment, the second tank 6 is provided at one end (the left end in Fig. 2(a)) of the floating structure 2. The second tank 6 is a hollow box-shaped member, and is provided on the one end side of the installation position of the tower 3. A drain port 9 for draining the ballast water 8 is formed on the outer (one end) side of the second tank 6. The drain port 9 faces the outside of the floating structure 2, and when the drain port 9 is opened, the ballast water is naturally drained, and the drained ballast water 8 flows directly down to the water surface around the floating structure 2.
The second tank 6 is provided at a position (eccentricity e3) eccentric to the center of the floating structure 2, and when ballast water 8 having a weight W3 is stored in the second tank 6, a third overturning moment M3 (=W3×e3) acts on the floating structure 2. The weight of the ballast water 8 stored in the second tank 6 is set to a size such that a third overturning moment M3 that cancels out the second overturning moment M2 acting on the floating structure 2 by the ballast material 7 acts on the floating structure 2 before the tower 3 is installed.

The method for assembling a floating wind power generation facility of this embodiment will be described below. The method for assembling a floating wind power generation facility of this embodiment is shown in Fig. 3. As shown in Fig. 3, the method for assembling a floating wind power generation facility of this embodiment includes a mooring process S1, a temporary fixing process S2, a tower self-supporting process S3, and a wind turbine installation process S4. Figures 4(a) to (d) show the working conditions of each process.
In the mooring step S1, as shown in FIG. 4(a), the floating structure 2 is moored at a predetermined position. The floating structure 2 is towed to a predetermined position and moored to a pile or the like (not shown). The first tank 5 of the floating structure 2 is filled with ballast material 7 for ensuring the horizontality of the floating structure 2 after the tower 3 and the tower body 4 are installed. That is, the first tank 5 stores ballast material 7 of a weight that generates a second overturning moment M2 on the floating structure 2, the second overturning moment M2 being equal to or greater than the first overturning moment M1 that occurs when the tower 3 is installed on the floating structure 2. The second tank 6 stores ballast water 8 for ensuring the horizontality of the floating structure 2 before the tower 3 is installed. That is, the second tank 6 stores ballast water 8 in an amount that generates a third overturning moment M3 on the floating structure 2, the third overturning moment M3 being equal to or greater than the first overturning moment M1 that acts on the floating structure 2 on which the tower 3 is installed and equal to the second overturning moment M2 that is generated by the ballast material 7.

In the temporary fixing step S2, the tower 3 is temporarily fixed on the floating structure 2. As shown in FIG. 4(b), the tower 3 is erected on the floating structure 2 using a crane 12, and is temporarily fixed to the floating structure 2 with bolts or the like while being suspended by the crane 12. That is, in the temporary fixing step S2, since the tower 3 is suspended by the crane 12, the weight of the tower 3 does not act on the floating structure 2, and the balance of the floating structure 2 due to the ballast material 7 and ballast water 8 is maintained. In this embodiment, a crane 12 provided on a crane ship 13 is used.

In the tower self-supporting step S3, the tower 3 is released from the crane 12 to make the tower self-supporting on the floating structure 2. As shown in FIG. 4(c), the tower 3 is erected on the floating structure 2 while being suspended by the crane 12. In addition, the ballast water 8 stored in the second tank 6 is discharged. When the ballast water 8 is discharged from the second tank 6, a rotational force (second overturning moment M2) is generated in the floating structure 2 due to the weight of the ballast material 7 (first tank 5) acting on the other end side of the floating structure 2, but since the tower 3 is in contact with the upper surface of one end side of the floating structure 2, the horizontality of the floating structure 2 is maintained. As the water is discharged from the second tank 6, the load of the tower 3 acting on the crane 12 decreases. In other words, when the ballast water 8 is discharged from the second tank 6, the one end side of the floating structure 2 tries to float up and naturally pushes back the tower 3, so that the horizontality is automatically maintained. When the floating structure 2 is balanced by the weight W1 of the tower 3 and the weight W2 of the ballast material 7 after the ballast water 8 has been discharged from the second tank 6, the tower 3 is removed from the crane 12 (the sling wire is removed from the tower 3) as shown in FIG. 4(d).

In the wind turbine installation process S4, the wind turbine body 4 is attached to the tower 3 (see Figure 1). The work of attaching the wind turbine body 4 to the tower 3 is performed using a crane 12. In the wind turbine installation process S4, ballast water 8 is drained from the second tank 6 in parallel with the installation of the wind turbine body 4. The ballast water 8 is drained according to the timing of installation of the wind turbine body 4 (blades 10 and nacelle 11) on the tower 3. When the ballast water 8 is drained from the second tank 6, a rotational force acts on the floating structure 2 due to the weight W2 of the ballast material 7, but the rotational force is canceled out by the weight of the tower 3 and the wind turbine body 4, ensuring the horizontality of the floating structure 2.

According to the method for assembling a floating wind power generation facility of this embodiment, the horizontality of the floating structure 2 is ensured by the first tank 5 (ballast material 7) and the second tank 6 (ballast water 8) until the tower self-supporting process, so that the rotation of the floating structure 2 is suppressed. In other words, the stability and horizontality are ensured when erecting the tower 3, improving workability. In addition, when the tower 3 is made to stand on the floating structure 2, the balance is ensured by the tower 3 and the ballast material 7 by discharging the ballast water 8 from the second tank (ballast water storage tank) 6. In other words, the stability and horizontality are ensured when the support of the tower 3 by the crane is released. The discharge of the ballast water 8 from the second tank 6 is achieved instantly by simply opening the drainage port 9, so it can be performed more easily and in a shorter time than when using a pump. Thus, according to the floating wind power generation facility assembly method and floating structure 2 of this embodiment, even if the center of gravity of the floating structure 2 and the center of gravity of the tower 3 do not coincide when assembling the wind turbine on the floating structure 2, the floating structure 2 is prevented from tilting when the tower 3 is placed on top, making it possible to carry out efficient construction while ensuring horizontality.

The amount of ballast water 8 stored in advance in the second tank 6 is the amount that causes an overturning moment (third overturning moment M3) acting on the floating structure 2 when the tower 3 is installed, which is equal to or greater than the overturning moment (first overturning moment M1) acting on the floating structure 2. Therefore, even if the overturning moment acting on the floating structure 2 increases due to the attachment of the wind turbine body 4 to the tower 3, the horizontality of the floating structure 2 is ensured. In other words, when attaching the wind turbine body 4 (blades 10 and nacelle 11) to the tower 3, the horizontality of the floating structure 2 can be ensured by discharging the ballast water 8 from the second tank 6 so as to cancel the overturning moment associated with the installation of the wind turbine body 4. In this way, the floating structure 2 can adjust the amount of ballast water 8 in the second tank 6 according to the construction status of the tower 3 and the wind turbine body 4, ensuring horizontality and enabling stable construction.

The horizontality of the floating structure 2 is ensured by using ballast water 8 (second tank 6), which shortens the time required for horizontal adjustment during construction. In addition, the ballast water 8 can be discharged in a short time, which shortens the time that the crane 12 is tied up, reducing the cost of using the crane 12, and by repurposing the crane 12 to assemble other floating wind power generation facilities 1, the overall construction period can be shortened.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and each of the above-described components can be appropriately modified without departing from the spirit of the present invention.
For example, the location where the first tank 5 is installed is not limited to inside the floating structure 2, and may be provided, for example, on the floating structure 2. In addition, in the above embodiment, the ballast material 7 is charged into the first tank 5, but the ballast material 7 may be placed directly inside or on the floating structure 2.
In the above embodiment, water is used as the ballast material 7, but the material constituting the ballast material 7 is not limited, and may be, for example, concrete, crushed stone, etc. Furthermore, the ballast material 7 used during construction may be appropriately replaced with other materials, equipment, etc. For example, when a power transmission facility or the like is provided on the other end side (the opposite side to the tower 3) of the floating structure 2, the ballast material 7 in the first tank 5 may be discharged in conjunction with the installation of the power transmission facility.
In the above embodiment, the ballast water 8 is discharged from the second tank 6, but the horizontality may be maintained by moving the ballast water 8 to the first tank 5.
In addition, if the ballast material 7 is installed at the same time as the tower 3 is installed, the second tank 6 can be omitted.

The installation location of the second tank (ballast water storage tank) 6 is not limited to on the floating structure 2, and may be, for example, inside the floating structure 2. In the above embodiment, one second tank 6 is provided on the outer side (one end side) of the floating structure 2 relative to the installation location of the tower 3 (see FIG. 1 ), but the number and installation locations of the second tanks 6 are not limited, and for example, one second tank 6 may be provided on each side of the tower 3 so that the center of gravity is located on the tower 3 side, as shown in FIGS. 5( a) and (b).
In the above embodiment, in the wind turbine installation process S4, ballast water 8 is discharged from the second tank 6 in parallel with the installation work of the wind turbine main body 4. However, instead of discharging the ballast water 8, the amount of ballast material 7 may be increased to ensure the stability (levelness) of the floating structure 2.
The crane 12 used is not limited to one installed on a crane ship 13. For example, when installing a tower 3 on a floating structure 2 moored in a dock or on a quay, a crane 12 installed adjacent to the dock or quay may be used.

1 Floating wind power generation facility 2 Floating structure 3 Tower 4 Wind turbine body 5 First tank 6 Second tank (ballast water storage tank)
7 Ballast material 8 Ballast water 9 Drain port 10 Blade 11 Nacelle 12 Crane

Claims (3)

a mooring step of mooring the floating structure at a predetermined position;
a temporary fixing process of temporarily fixing the tower suspended by the crane in an upright state on the floating structure;
a tower supporting step of supporting the tower on the floating structure;
A method for assembling a floating wind power generation facility comprising:
The floating structure is provided with a ballast material for ensuring horizontality after the tower is installed, and a ballast water storage tank for storing ballast water for ensuring horizontality before the tower is installed,
The method for assembling a floating wind power facility is characterized in that, in the tower self-supporting process, the ballast water previously stored in the ballast water storage tank is discharged and the tower is removed from the crane. The method for assembling a floating wind power generation facility according to claim 1, characterized in that the amount of ballast water stored in advance in the ballast water storage tank is an amount that causes an overturning moment acting on the floating structure on which the tower is installed to be greater than or equal to the overturning moment acting on the floating structure. The method further includes a wind turbine mounting step of mounting a wind turbine body to the tower,
3. The method for assembling a floating wind power facility according to claim 1 or 2, characterized in that in the wind turbine installation process, ballast water is discharged from the ballast water storage tank or the amount of ballast material is increased in parallel with the installation work of the wind turbine main body.

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