JP7474669B2 - How to mount a wind turbine on an offshore wind power generation facility - Google Patents

Description

The present invention relates to a method for mounting wind turbines on offshore wind power generation facilities that are installed in relatively deep waters.

Traditionally, hydroelectric, thermal and nuclear power generation have been the main power generation methods used, but in recent years, wind power generation, which uses natural wind to generate electricity, has been attracting attention from the perspective of the environment and the effective use of natural energy. Wind power generation facilities can be installed on land or on water (mainly offshore), but in Japan, which has mountainous terrain behind its coasts, there are few plains along the coast where stable winds can be expected. On the other hand, Japan is surrounded by sea on all sides, and the sea has the advantage that winds suitable for generating electricity can be easily obtained and there are fewer restrictions on installation. As a result, many proposals have been made in recent years for offshore wind power generation facilities, their construction methods and floating structures.

For example, the following Patent Document 1 proposes an offshore wind power generation facility consisting of a float, mooring lines, a tower, and a nacelle and multiple blades installed at the top of the tower, in which the float is a spar-type floating structure consisting of a lower concrete floating structure in which concrete precast cylindrical bodies are stacked vertically in multiple tiers and each precast cylindrical body is fastened and integrated with PC steel, and an upper steel floating structure connected to the upper side of the lower concrete floating structure. Note that a spar-type refers to a floating structure with a long, slender cylindrical shape like a rod-shaped fishing float.

When installing the spar-type offshore wind power generation equipment at sea, it is desirable to carry out construction in a bay with calm waves, but construction in a bay is difficult because the draft (part below the water surface) of the float is generally deep, at more than 70 m, while the water depth in a bay is generally shallower than this. For this reason, when installing the wind turbines, as shown in Patent Document 2 below, they have been installed outside the bay where the water is deep, using a large crane ship.

Japanese Patent No. 5274329 JP 2012-201219 A

However, there are currently only four large crane ships in Japan, which are necessary for constructing offshore wind power generation facilities, and because they cannot move on their own, three to four tugboats or other boats are needed to operate them, which means daily usage fees of more than 10 million yen are required, making the costs very high. If dozens of offshore wind power generation facilities were to be constructed, the ships would need to be tied up for long periods of time, which would pose a problem as the costs of using these large crane ships would become enormous.

The problem with large crane ships is that their natural period is around 7 seconds, making them susceptible to resonating with swells from offshore. Also, because the rocking characteristics of floating structures and large crane ships in response to waves are completely different, the different rocking periods can make work dangerous. In addition, this inevitably leads to a poor operating rate, which extends the period the large crane ship is detained, resulting in increased costs.

On the other hand, wind turbines have become larger in recent years, with 10MW class wind turbines having nacelle heights exceeding 100m, creating problems with the inability of existing large crane ships in Japan to reach them due to insufficient lifting range. To address this issue, it would be necessary to build a new large crane ship, but the construction costs would run into the hundreds of billions of yen, making construction too expensive and problematic.

The first object of the present invention is to provide a method for mounting a wind turbine on an offshore wind power generation facility, which is related to the installation of the offshore wind power generation facility at sea and enables the wind turbine to be easily and safely mounted on the tower of the offshore wind power generation facility without using a large crane ship.

The second objective is to provide a method for mounting wind turbines on a given number of offshore wind power generation facilities with integrated towers without using a large crane ship or while minimizing the use of a large crane ship.

In order to solve the above problems, the present invention as claimed in claim 1 provides a method of mounting a wind turbine on an offshore wind power generation facility, characterized in that a crane-mounted float is manufactured by attaching a tower identical to that of the offshore wind power generation facility to be installed on the sea to a float identical to that of the offshore wind power generation facility to be installed on the sea , and providing crane equipment at the top of the tower, and then using this crane-mounted float to mount the wind turbine on the tower of the offshore wind power generation facility to be installed on the sea.

In the invention described in claim 1 above, a tower similar to that of the offshore wind power generation facility to be installed at sea is attached to a float similar to that of the offshore wind power generation facility to be installed at sea , and a crane-equipped float with crane equipment at the top of the tower is used instead of a large crane ship, and a wind turbine is then mounted on the tower of the offshore wind power generation facility to be installed at sea.

The crane-mounted float has a structure that uses the float and tower of an offshore wind power generation facility as is, which makes the manufacturing cost significantly cheaper than that of a large crane ship, and also ensures a sufficient lifting height, making it possible to construct even large wind power generation facilities. Furthermore, the crane-mounted float can be used as an offshore wind observation tower, and can also be used for maintenance (operation and maintenance inspection).

In addition, the crane-mounted float and the float of the offshore wind power generation facility to be installed on the sea have the same shape and structure, and have the same rocking characteristics in response to waves, so there is less rocking, making it easier and safer to mount the wind turbines on the tower of the offshore wind power generation facility, and naturally increasing the operating rate.

According to a second aspect of the present invention, there is provided a method for installing a crane-equipped float on the sea, the method comprising: a first step of attaching a tower, which is the same as the tower of an offshore wind power generation facility to be installed on the sea, to a float, which is the same as the float of an offshore wind power generation facility to be installed on the sea, and floating the crane-equipped float on the sea, the tower being provided with a crane facility at the top of the tower;
a second step of slinging the wind turbine onto a hook of a crane equipment when the barge carrying the wind turbine is brought close to the crane-mounted float;
a third step of lifting the wind turbine to the top while moving the barge aside after the wind turbine is lifted off the ground by discharging ballast water from the crane-mounted float;
a fourth step of connecting the suspended wind turbine to the top of the tower of the offshore wind power generation facility to be installed on the sea when the floating body of the offshore wind power generation facility, which is equipped with an integrated tower, is brought close to the crane-mounted floating body;
and a fifth step of transferring the weight of the wind turbine to the float of the offshore wind power generation facility to be installed on the sea by moving ballast water equivalent to the weight of the wind turbine from the float of the offshore wind power generation facility to be installed on the sea to the crane-mounted float.

The invention described in claim 2 above specifies the method of mounting a wind turbine on an offshore wind power generation facility of the present invention according to specific steps. Specifically, a crane-mounted float is floated on the sea (first step), and once a barge carrying a wind turbine is brought close to the crane-mounted float, the wind turbine is sling-hooked onto the hook of the crane equipment (second step). Next, once the wind turbine is removed from the ground by draining the ballast water from the crane-mounted float, the wind turbine is hoisted up to the top while the barge is moved aside (third step).

Next, when the float of the offshore wind power generation facility to be installed on the sea, which has an integrated tower, is brought close to the crane-mounted float, the suspended wind turbine is connected to the top of the tower of the offshore wind power generation facility to be installed on the sea (fourth step), and while in this state (the weight of the wind turbine is still supported by the crane-mounted float), ballast water equivalent to the weight of the wind turbine is transferred from the float of the offshore wind power generation facility to be installed on the sea to the crane-mounted float, so that the weight of the wind turbine is transferred to the float of the offshore wind power generation facility to be installed on the sea (fifth step).

By following the above steps, it becomes possible to easily and safely mount wind turbines onto the tower of an offshore wind power generation facility without using a large crane ship.

The present invention according to claim 3 provides a method of mounting a wind turbine on an offshore wind power generation facility according to claim 2, in which in the fourth step, the draft of the float of the offshore wind power generation facility to be installed on the sea is set to the draft after the wind turbine is mounted.

The invention described in claim 3 above is such that in the fourth step, the draft of the float of the offshore wind power generation facility to be installed on the sea is set to the draft after the wind turbine is installed. This is because in the fifth step, ballast water equivalent to the weight of the wind turbine is moved from the float of the offshore wind power generation facility to be installed on the sea to the crane-mounted float, and the weight of the wind turbine is transferred to the float of the offshore wind power generation facility to be installed on the sea. By setting the draft of the float to the draft after the wind turbine is installed, it is possible to make the draft of the float the same before and after the wind turbine is installed.

The present invention according to claim 4 provides a method of mounting a wind turbine on an offshore wind power generation facility according to claims 2 and 3, in which the wind turbine is made up of a nacelle and three blades attached thereto, and in the second step, a wind turbine consisting of a nacelle and two blades attached thereto is sling-mounted and attached to the tower of the offshore wind power generation facility to be installed on the sea in the manner up to the fifth step, and then the remaining blade is attached to the nacelle using the crane-mounted float after the fifth step.

As described below, the invention described in claim 4 above allows the wind turbine, including the nacelle and three blades, to be attached to the tower of the offshore wind power generation facility to be installed at sea in one operation. However, taking into consideration the loading condition of the wind turbine on the barge, the wind turbine is divided into a wind turbine consisting of a nacelle and two blades attached to it, and the remaining blade, and the procedure is such that the wind turbine consisting of the nacelle and two blades attached to it is first attached, and then the remaining blade is attached.

According to a fifth aspect of the present invention, there is provided a method for mounting wind turbines on the sea for a predetermined number of offshore wind power generation facilities integrally equipped with towers, comprising the steps of:
A first step of manufacturing floating bodies for the offshore wind power generation facilities in a number equal to a predetermined number of offshore wind power generation facilities to be installed plus one;
A second step is to set up a crane on top of the tower of some of the floating structures of the offshore wind power generation facilities to turn them into crane-mounted floating structures and to float them on the sea.
a third step of mounting the wind turbine on the tower of the offshore wind power facility to be installed on the sea by the second to fifth steps of the method for mounting the wind turbine on the offshore wind power facility according to any one of claims 2 to 4 using the several crane-mounted floats;
The present invention provides a method for mounting a wind turbine on an offshore wind power generation facility, characterized in that it comprises a fourth step of transferring the crane equipment of the remaining crane-mounted floats to the wind turbine using one or more of the several crane-mounted floats, or repeating this process, until only one crane-mounted float remains.

The invention described in claim 5 above provides an efficient method for mounting wind turbines on a given number of offshore wind power generation facilities with integrated towers, for example, several dozen offshore wind power generation facilities, without using a large crane ship. As mentioned above, the crane-mounted float can be used as an offshore wind observation tower and can also be used for maintenance (operation and maintenance inspection).

According to a sixth aspect of the present invention, there is provided a method for mounting wind turbines on the sea for a predetermined number of offshore wind power generation facilities integrally equipped with towers, comprising the steps of:
A first step of manufacturing a number of floating bodies for the offshore wind power generation facilities equal to a predetermined number of offshore wind power generation facilities to be installed;
A second step is to set up a crane on the top of the tower of some of the floating structures of the offshore wind power generation facilities to turn them into crane-mounted floating structures and to float them on the sea.
a third step of mounting the wind turbine on the tower of the offshore wind power facility to be installed on the sea by the second to fifth steps of the method for mounting the wind turbine on the offshore wind power facility according to any one of claims 2 to 4 using the several crane-mounted floats;
a fourth step of transferring the crane equipment of the remaining crane-mounted floats to the wind turbines using one or more of the crane-mounted floats among the several crane-mounted floats, or repeating the above steps, so that only one crane-mounted float is left;
There is provided a method for mounting a wind turbine on an offshore wind power generation facility, which comprises a fifth step of mounting the wind turbine after removing the crane equipment from one crane-mounted float using a large crane ship.

The invention described in claim 6 above provides an efficient method for mounting wind turbines on a given number of offshore wind power generation facilities with integrated towers, for example, several dozen offshore wind power generation facilities, while using a large crane ship only once.

As explained in detail above, according to the present invention (claims 1 to 4), it is possible to easily and safely mount wind turbines on the tower of an offshore wind power generation facility without using a large crane ship when installing the facility at sea.

Furthermore, according to the present invention (claims 5 and 6), it becomes possible to mount wind turbines on a given number of offshore wind power generation facilities with integrated towers without using a large crane ship or while minimizing the use of a large crane ship.

FIG. 1 is an overall side view of a spar-type floating offshore wind power generation facility 1. FIG. Showing a precast cylindrical body 15, (A) is a longitudinal cross-sectional view, (B) is a plan view (viewed along line B-B), and (C) is a bottom view (viewed along line C-C). 1A and 1B are diagrams showing how precast cylindrical bodies 15 are fastened together. A vertical cross-sectional view showing the boundary between the lower concrete floating structure section 4A and the upper steel floating structure section 4B. FIG. 2 is an overall side view showing the crane-mounted floating body 2 according to the present invention. 1 shows a crane equipment 3, in which (A) is a side view and (B) is a plan view. This shows a procedure (part 1) for mounting a wind turbine on an offshore wind power generation facility 1. This is a second procedure for mounting a wind turbine on an offshore wind power generation facility 1. This is a third procedure for mounting a wind turbine on an offshore wind power generation facility 1. This is a fourth procedure for mounting a wind turbine on an offshore wind power generation facility 1. This is a fifth step in the method for mounting a wind turbine on an offshore wind power generation facility 1. This is a diagram showing how to load a barge when carrying out the construction of wind turbines all at once.

The following describes in detail the embodiments of the present invention with reference to the drawings.

[Spar-type floating offshore wind turbine 1]
Before describing the "method of mounting a wind turbine on an offshore wind power generation facility" according to the present invention, a structural example of a spar-type floating offshore wind power generation facility 1 will be described in detail with reference to Figs. 1 to 5.

As shown in FIG. 1, the offshore wind power generation facility 1 is composed of a cylindrical floating body 4, a mooring line 5, a tower 6, and a wind turbine 7 consisting of a nacelle 8 and multiple blades 9, 9, etc., installed at the top of the tower 6.

As shown in FIG. 2, the float 4 is made up of a lower concrete floating structure 4A in which concrete precast cylindrical bodies 15, 15... are stacked vertically in multiple tiers and each precast cylindrical body 15, 15... is fastened together with PC steel members 19 to form an integrated structure, and an upper steel floating structure 4B connected to the upper side of the lower concrete floating structure 4A.

Ballast materials such as water, gravel, fine or coarse aggregate, and metal particles can be introduced or discharged into or from the hollow portion of the floating body 4, making the buoyancy (draft) adjustable. The introduction/discharge of ballast materials is possible by employing the fluid transport method previously proposed by the applicant in JP 2012-201217 A.

The precast cylindrical bodies 15 constituting the lower concrete floating structure section 4A are circular cylindrical precast members with the same cross section in the axial direction as shown in FIG. 3, and each is manufactured using the same formwork, or hollow precast members manufactured by centrifugal molding are used.

In addition to the reinforcing bars 20, sheaths 21, 21... are embedded in the wall at appropriate intervals in the circumferential direction for inserting the PC steel bars 19. The lower ends of these sheaths 21, 21... are formed with sheath enlarged diameter sections 21a so that couplers for connecting the PC steel bars 19 can be inserted, and the upper sections are formed with box-opening sections 22 for fitting anchor plates for fixing. In addition, multiple hanging fittings 23 are provided on the top surface.

As shown in Figure 4(A), the precast cylindrical bodies 15 are fastened together by stacking the precast cylindrical bodies 15, 15 while inserting the PC steel rods 19, 19... extending upward from the lower precast cylindrical body 15 through the sheaths 21, 21..., and then fitting the anchor plate 24 into the box-out section 22, and introducing tension into the PC steel rods 19 with the nut member 25 to integrate them. In addition, grout material is injected into the sheaths 21 through the grout injection hole 27 (see Figure 4(B)). The hole 24a formed in the anchor plate 24 is a grout injection confirmation hole, and the filling of the grout material is completed when the grout material is discharged from the confirmation hole.

Next, as shown in Figure 4(B), a coupler 26 is screwed onto the protruding portion of the PC steel rod 19 to connect the upper PC steel rods 19, 19..., and the PC steel rods 19, 19... are then inserted into the sheaths 21, 21... of the upper precast cylindrical body 15 while being stacked, and the procedure of fixing the PC steel rods 19 in place in the above manner is repeated in order to stack them up in the height direction. At this time, an adhesive 28 such as an epoxy resin-based adhesive or sealant is applied to the joint surfaces between the lower precast cylindrical body 15 and the upper precast cylindrical body 15 to ensure watertightness and to bond the mating surfaces.

As shown in FIG. 2, the upper steel floating structure 4B is composed of a steel tubular body 17 located relatively on the lower side and a steel tubular body 18 located relatively on the upper side. The lower steel tubular body 17 has a lower portion with the same outer diameter as the precast tubular body 15, and is connected to the precast tubular body 15. The upper portion of the steel tubular body 17 has a truncated cone shape with a gradually narrowing diameter.

The upper steel cylindrical body 18 is a cylindrical body whose outer diameter is continuous with the upper outer diameter of the lower steel cylindrical body 17, and is connected to the lower steel cylindrical body 17 by bolts or welding (bolt fastening is used in the illustrated example).

The tower 6 is made of steel, concrete or PRC (prestressed reinforced concrete), but it is preferable to use one made of steel so that the total weight is small. The outer diameter of the tower 6 and the outer diameter of the upper steel cylindrical body 18 are almost the same, and the outer shape is continuous in the vertical direction without any steps. In the illustrated example, a ladder 13 is provided at the top of the upper steel cylindrical body 18, and a walkway scaffolding 14 is provided circumferentially at approximately the boundary between the tower 6 and the upper steel cylindrical body 18.

As shown in Figure 1, the mooring point K of the mooring line 5 to the float 4 is set below sea level and at a position higher than the center of gravity G of the float 4. This makes it possible to prevent the ship from coming into contact with the mooring line 5. In addition, a resistance moment is generated around the center of gravity G of the float 4 at the mooring point to prevent the float 4 from tipping over too much, so that the tilting attitude of the tower 6 can be appropriately maintained.

The nacelle 8 is a device equipped with a generator that converts the rotation of the wind turbine 7 into electricity and a controller that can automatically change the angle of the blades 9.

[How to mount a wind turbine on an offshore wind power generation facility]
A method for mounting a wind turbine on an offshore wind power generation facility according to the present invention will be described.

As shown in Figure 6, the method of mounting a wind turbine according to the present invention involves attaching the tower 6 to a float 4 that is the same as the float 4 of the offshore wind power generation facility 1 to be installed on the sea, and using a crane - mounted float 2 that has crane equipment 3 on the top of the tower 6, mounting a wind turbine 7 on the tower 6 of the offshore wind power generation facility 1 to be installed on the sea.

In other words, the base is a float 4 of an offshore wind power generation facility 1 with a tower 6 attached, to which a crane equipment 3 is attached to form a crane-mounted float 2, which can be used as a substitute for a large crane ship. As shown in detail in FIG. 7, the crane equipment 3 is composed of a post 30 connected to the top of the tower 6, a jib 31 oriented horizontally and connected to the top of the post 30, a hoisting equipment 32 suspended from the tip of the jib 31, a winch (not shown), and a water tank (weight) 33 installed on the jib 31 across the post 30 on the opposite side to the side where the hoisting equipment 32 is installed, in order to reduce or eliminate the inclination of the crane-mounted float 2 when hoisting a load.

The hoisting equipment 32 is composed of a top sheave 34 located at the top, a hook 36 that moves up and down, and a wire rope 35 wound around these. The water tank 33 is equipped with a water filling device and a water draining device, and the amount of water in the water tank can be adjusted according to the lifting weight.

The crane-mounted float 2 uses the same structure as the float 4 and tower 6 of the offshore wind power generation facility 1, so the manufacturing cost is much cheaper than that of a large crane ship. In addition, regardless of the size of the offshore wind power generation facility 1, the lifting height can be sufficiently secured. Furthermore, the crane-mounted float 2 and the float 4 of the offshore wind power generation facility 1 to be installed on the sea have the same structure and the same rocking characteristics against waves, so there is less relative rocking, and it becomes possible to easily and safely mount the wind turbine on the tower 6 of the offshore wind power generation facility 1. Since the rocking characteristics are the same and they rock with the same period, restrictions on waves are relaxed, and while the natural period of the spar-type float exceeds 20 seconds, the wave period is about 5 seconds, so both are less susceptible to the effects of waves, which increases the operating rate and contributes to shortening the construction period.

<How to mount a wind turbine on an offshore wind power generation facility (part 1)>
Next, a method for mounting a wind turbine on an offshore wind power generation facility according to the present invention will be described in detail following specific steps.

(First Procedure)
First, as shown in FIG. 6 , a tower 6 is attached to a float 4 identical to the float 4 of the offshore wind power generation facility 1 to be installed on the sea, and a crane-equipped float 2 having a crane equipment 3 on the top of the tower 6 is floated and installed on the sea.

(Second Procedure)
As shown in FIG. 8, when the barge 37 carrying the wind turbine 7 ′ is brought close to the crane-mounted floating body 2 , the wind turbine 7 ′ is sling-loaded onto the hook 36 of the crane equipment 3 .

Here, taking into consideration the loading condition of the wind turbine 7 on the barge 37, the wind turbine 7' is made to be a wind turbine consisting of a nacelle 8 and two blades 9, 9 attached thereto. In other words, the wind turbine 7 is originally composed of a nacelle 8 and three blades 9, 9... attached thereto, but taking into consideration the loading condition on the barge 37, in the second procedure, a wind turbine 7' consisting of a nacelle 8 and two blades 9, 9 attached thereto is made, and after this is attached to the tower 6 of the offshore wind power generation facility 1, the remaining blade 9 is attached in a subsequent process.

(Third Procedure)
As shown in FIG. 8, once the wind turbine 7' has been removed from the ground by discharging the ballast water from the crane-mounted float 2, the wind turbine 7' is hoisted up to the top while the barge 37 is moved aside, as shown in FIG. 9.

The reason why the wind turbine 7' is cut off by discharging ballast water is that if the wind turbine is to be lifted by a crane, the crane-mounted float 2 will sink due to the weight of the wind turbine, and the barge 37 will rise because it is lighter by the weight of the wind turbine, making it difficult to lift the wind turbine 7' by hoisting the crane. By simply using the force of the crane-mounted float 2 rising by discharging ballast water alone to cut off the wind turbine, it is possible to cut off the wind turbine slowly, reliably, and safely. When discharging the ballast water, if the discharge destination is the barge 37, as shown by the dotted line in Figure 4, it is possible to cut off the wind turbine more quickly and the work can be performed more safely because the draft does not change. In addition, by pouring water into the water tank (weight) 33, the tilt of the crane-mounted float 2 can be suppressed.

(Fourth Procedure)
10, when the float 4 of the offshore wind power generation facility 1 to be installed on the sea, which has an integral tower 6, is brought close to the crane-mounted float 2, the suspended wind turbine 7' is connected to the top of the tower 6 of the offshore wind power generation facility 1 to be installed on the sea. In this fourth step, it is desirable to fill the float 4 of the offshore wind power generation facility 1 to be installed on the sea with ballast water in order to transfer the wind turbine load in the fifth step described below, so as to achieve the draft state after the wind turbine is installed.

At this time, the wind turbine 7' is connected to the top of the tower 6 of the offshore wind power generation facility 1', but the wind turbine load is not transferred to the offshore wind power generation facility 1' but is supported thereon.

(Fifth Step)
As shown in Figure 11, ballast water equivalent to the weight of the wind turbine is transferred from the float 4 of the offshore wind power generation facility 1 to be installed on the sea to the crane-mounted float 2, so that the weight of the wind turbine 7' is transferred to the float 4 of the offshore wind power generation facility 1 to be installed on the sea. The offshore wind power generation facility 1 to be installed on the sea rises as the amount of ballast water decreases and begins to support the weight of the wind turbine 7', while the crane-mounted float 2 descends as ballast water is injected, and the weight of the wind turbine 7' is transferred to the offshore wind power generation facility 1. The amount of ballast water transferred is equivalent to the weight of the wind turbine 7'.

(Sixth Step)
Finally, as shown in Fig. 12, the remaining blade 9 is attached to the nacelle 8 using the crane-mounted float 2. The blade 9 is lightweight, so work can be done by hoisting it with the crane equipment 3, but even in this case, it is possible to transfer the weight of the blade 9 to the float 4 of the offshore wind power generation facility 1 to be installed on the sea by moving ballast water equivalent to the weight of the blade 9 from the float 4 of the offshore wind power generation facility 1 to be installed on the sea to the crane-mounted float 2.

<How to mount a wind turbine on an offshore wind power generation facility (part 2)>
Next, a method for mounting wind turbines on a predetermined number of offshore wind power plants integrally equipped with towers using the above-mentioned method for mounting wind turbines on offshore wind power plants according to the present invention will be described in detail. Here, the predetermined number refers to mounting wind turbines on at least three or more offshore wind power plants, preferably six or more, and more preferably several tens of offshore wind power plants.

(First Procedure)
The number of floats 4 for the offshore wind power generation facilities 1 is manufactured equal to the number of the predetermined number of offshore wind power generation facilities to be installed plus one. The first step specifies the number of floats for the offshore wind power generation facilities 1 to be manufactured. Specifically, the number is set to be one more than the predetermined number of offshore wind power generation facilities 1 to be installed. For example, if 100 offshore wind power generation facilities 1 are to be installed, then the floats 4 for 101 offshore wind power generation facilities 1 are manufactured. The same number of towers 6 are also manufactured and attached to the floats 4.

(Second Procedure)
Some of the floats 4 of the offshore wind power generation facilities 1 are provided with a crane facility 3 at the top of the tower 6 to become crane-mounted floats 2, which are then floated on the sea. In other words, some of the floats 4 of the manufactured offshore wind power generation facilities 1 are used as crane-mounted floats 2. For example, six of the manufactured 101 offshore wind power generation facilities 1 are modified to become crane-mounted floats 2 by mounting the crane facility 3 thereon.

(Third Procedure)
Using the several crane mounted floats 2, wind turbines are mounted on the towers 6 of the offshore wind power generation facilities 1 to be installed on the sea in the second to fifth steps of the wind turbine mounting procedure according to the present invention described above. For example, six crane mounted floats 2 are used to mount wind turbines 5 on the towers 6 of 95 offshore wind power generation facilities 1. If the work of 95 offshore wind power generation facilities 1 is shared among the six crane mounted floats 2, the number of facilities that one crane mounted float 2 is responsible for is 95/6=15.8. Assuming that it takes one day per facility, it is calculated that it will take 16 days to mount wind turbines on 95 offshore wind power generation facilities 1.

(Fourth Procedure)
The crane equipment 3 of the remaining crane-mounted floats 2 is replaced with the wind turbine 7 by one or more of the crane-mounted floats 2 among the several crane-mounted floats 2, or the above process is repeated until only one crane-mounted float remains. In other words, the crane equipment 3 is replaced with the wind turbine 7 between the offshore wind power generation facilities 1 modified to the crane-mounted floats 2. For example, the wind turbines of five offshore wind power generation facilities 1 are replaced in sequence by one crane-mounted float 2, or the wind turbines of three offshore wind power generation facilities 1 are replaced by three crane-mounted floats 2. In the latter case, the process is repeated again, specifically, one of the three is used to replace the wind turbines of two offshore wind power generation facilities 1. This procedure leaves only one crane-mounted float 4 at the end. If it takes one day per facility, it is calculated that it will take five to three days to replace the wind turbines of the offshore wind power generation facilities 1 modified to the crane-mounted floats 2.

The above procedure makes it possible to mount the wind turbines on 100 offshore wind power generation facilities 1. The number of days required to complete the wind turbine mounting work is 21 to 19 days.
If this work were to be carried out using a large crane ship as in the past, it would take several days for each crane, so this method will enable significant improvements in work efficiency. The remaining crane-mounted float 2 can be used as an offshore wind observation tower and can also be used for maintenance (operation and maintenance inspection). It may also be stored separately in case of a breakdown in the offshore wind power generation facility 1.

<How to mount a wind turbine on an offshore wind power generation facility (part 3)>
This method also details a method for mounting wind turbines at sea on a specified number of offshore wind power generation facilities which have integral towers, using the method for mounting wind turbines on offshore wind power generation facilities according to the present invention described above. However, while the above-mentioned Method for Mounting Wind Turbines on Offshore Wind Power Generation Facilities (Part 2) involved fabricating the number of floats equal to the number of units to be installed + 1, this method differs from the above-mentioned Method for Mounting Wind Turbines on Offshore Wind Power Generation Facilities (Part 2) in that the number of floats fabricated is the same as the number of units to be installed.

(First Step)
The floats 4 for the offshore wind power generation facilities 1 are manufactured in the same number as the predetermined number of offshore wind power generation facilities 1 to be installed. The same number of towers 6 are also manufactured and attached to the floats 4.

(Second step to fourth step)
This is the same as the method for mounting a wind turbine on an offshore wind power generation facility (part 2) described above.

(Fifth Step)
A large crane ship is used to remove the crane equipment 3 from the remaining crane-mounted float 2, and then the wind turbine 7 is mounted on it. This method eliminates the waste of manufacturing one extra float 4. If the capacity is less than 10 MW and work can be done with a large crane ship, then the wind turbine can be transferred onto the last crane-mounted float 2 with a large crane ship, making it possible to mount the wind turbines 7 on the sea for a predetermined number of offshore wind power plants 1 without manufacturing an extra float.

[Other examples]
(1) In the above embodiment, the floating structure is a structure already implemented by the applicant, which is composed of a lower concrete floating structure 4A in which concrete precast cylindrical bodies 15, 15... are stacked vertically in multiple layers and each precast cylindrical body 15, 15... is fastened and integrated with PC steel members 19, and an upper steel floating structure 4B connected to the upper side of the lower concrete floating structure 4A. However, the entire float may be made of a concrete floating structure, or the entire float may be made of a steel floating structure.

(2) In the above embodiment, the divided wind turbine 7' consisting of the nacelle and the two blades attached thereto is first mounted on the offshore wind power generation facility 1, and then the remaining blade 9 is attached to the nacelle 8 using the crane-mounted float 2 after the fifth step. However, as shown in FIG. 13, a platform 38 may be provided on a barge 37 to form a wind turbine 7 with three blades 9, 9... integrated into one unit, and this may be mounted on the offshore wind power generation facility 1 as a whole in a single operation.

(3) In the above embodiment, the wind turbine has three blades, which is the most common number. However, the present invention can also be applied to wind turbines with two blades and wind turbines with four or more blades.

(4) In the present invention, a tower 6 is attached to a float 4 that is the same as the float 4 of the offshore wind power generation facility 1 that is installed on the sea, and a crane facility 3 is provided on the top of the tower 6 to form a crane-mounted float 2. In this case, the definition of a float 4 that is the same as the float 4 of the offshore wind power generation facility 1 is that it is desirable for it to be completely identical, but it does not mean that it is only completely identical. Basically, if they have the same structure and the same scale, they belong to the same category even if the fine structural parts are different.

(5) The present invention is primarily applicable as a method for mounting wind turbines on offshore wind power generation facilities with spar-type floating structures, but can also be similarly applied to offshore wind power generation facilities with semi-submersible floating structures, etc.

1...Spar-type floating offshore wind power generation equipment, 2...Crane-mounted float, 3...Crane equipment, 4...Float, 4A...Lower concrete floating structure, 4B...Upper steel floating structure, 5...Mooring line, 6...Tower, 7/7'...Wind turbine, 8...Nacelle, 9...Blade, 15...Precast tubular body, 17/18...Steel tubular body, 19...PC steel bar, 37...Barge

Claims (6)

A method for mounting a wind turbine on an offshore wind power generation facility , comprising the steps of: attaching a tower identical to that of the offshore wind power generation facility to be installed on the sea to a float identical to that of the offshore wind power generation facility to be installed on the sea , and fabricating a crane-mounted float by providing crane equipment at the top of the tower; and using this crane-mounted float to mount the wind turbine on the tower of the offshore wind power generation facility to be installed on the sea. A first step of installing a crane-equipped float having a tower the same as that of the offshore wind power generation facility to be installed on the sea attached to a float the same as that of the offshore wind power generation facility to be installed on the sea and a crane equipment provided on the top of the tower, by floating the crane-equipped float on the sea;
a second step of slinging the wind turbine onto a hook of a crane equipment when the barge carrying the wind turbine is brought close to the crane-mounted float;
a third step of lifting the wind turbine to the top while moving the barge aside when the wind turbine is lifted off the ground by discharging ballast water from the crane-mounted float;
a fourth step of connecting the suspended wind turbine to the top of the tower of the offshore wind power generation facility to be installed on the sea when the floating body of the offshore wind power generation facility, which is equipped with an integrated tower, is brought close to the crane-mounted floating body;
a fifth step of transferring the weight of the wind turbine to the float of the offshore wind power generation facility to be installed on the sea by moving ballast water equivalent to the weight of the wind turbine from the float of the offshore wind power generation facility to be installed on the sea to the crane-mounted float. The method for mounting a wind turbine on an offshore wind power generation facility according to claim 2, wherein in the fourth step, the draft of the float of the offshore wind power generation facility to be installed on the sea is set to the draft after the wind turbine is mounted. The wind turbine is composed of a nacelle and three blades attached thereto, and in the second step, a wind turbine consisting of a nacelle and two blades attached thereto is installed, and this is sling-loaded and attached to the tower of the offshore wind power generation facility to be installed on the sea in the manner up to the fifth step, and the remaining blade is then attached to the nacelle using the crane-mounted float after the fifth step. A method of installing a wind turbine on an offshore wind power generation facility according to either claim 2 or 3. A method for mounting wind turbines at sea for a predetermined number of offshore wind power generation facilities integrally equipped with towers, comprising:
A first step of manufacturing floating bodies for the offshore wind power generation facilities in a number equal to a predetermined number of offshore wind power generation facilities to be installed plus one;
A second step is to set up a crane on the top of the tower of some of the floating structures of the offshore wind power generation facilities to turn them into crane-mounted floating structures and to float them on the sea.
a third step of mounting the wind turbine on the tower of the offshore wind power facility to be installed on the sea by the second to fifth steps of the method for mounting the wind turbine on the offshore wind power facility according to any one of claims 2 to 4 using the several crane-mounted floats;
and a fourth step of using one or more of the several crane-mounted floats to transfer the crane equipment of the remaining crane-mounted floats to the wind turbine, or repeating this process, until only one crane-mounted float remains. A method for mounting wind turbines at sea for a predetermined number of offshore wind power generation facilities integrally equipped with towers, comprising:
A first step of manufacturing a number of floating bodies for the offshore wind power generation facilities equal to a predetermined number of offshore wind power generation facilities to be installed;
A second step is to set up a crane on the top of the tower of some of the floating structures of the offshore wind power generation facilities to turn them into crane-mounted floating structures and to float them on the sea.
a third step of mounting the wind turbine on the tower of the offshore wind power facility to be installed on the sea by the second to fifth steps of the method for mounting the wind turbine on the offshore wind power facility according to any one of claims 2 to 4 using the several crane-mounted floats;
a fourth step of transferring the crane equipment of the remaining crane-mounted floats to the wind turbines using one or more of the crane-mounted floats among the several crane-mounted floats, or repeating the above steps, so that only one crane-mounted float is left;
A method for mounting a wind turbine on an offshore wind power generation facility, comprising a fifth step of removing the crane equipment from one crane-mounted float using a large crane ship, and then mounting the wind turbine.

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