Method for assembling offshore wind power generation device

Abstract

To provide a method for assembling an offshore wind power generation device capable of suppressing relative oscillation upon connecting a lower structure and an upper structure, to perform assembly work efficiently.SOLUTION: A method for assembling an offshore wind power generation device comprises: connecting a tip of each oscillation suppression wire 10 pull out from a plurality of winches 15, 15, ... arranged at intervals circumferentially on an upper part of a lower structure 2 to a connector 11 provided at a lower end part of an upper structure 3; controlling the winches 15 so that the oscillation suppression wire 10 is maintained in a tension state with predetermined tension; and suspending the upper structure 3 down to above the lower structure 2 while suppressing oscillation.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for efficiently assembling an offshore wind turbine generator. [Background technology]

[0002] In recent years, the use of renewable energy has been promoted from the perspective of environmental impact and the effective use of natural energy, and among these, wind power generation, which has a large potential for generating electricity, has been attracting attention.

[0003] In particular, the offshore environment provides an environment in which winds suitable for wind power generation are more readily available than on land, making it a suitable environment for installing wind power generation equipment. Therefore, in recent years, there has been progress in the development and installation of offshore wind power generation equipment.

[0004] This offshore wind power generation device 1 is a tower-type structure comprising a floating or bottom-mounted lower structure 2 made of a monopile or the like, a tower-shaped upper structure 3 whose lower end is connected to the upper end of the lower structure 2, and wind power generation equipment 4 made up of a wind turbine (nacelle / rotor) etc. supported on the upper end of the upper structure 3.

[0005] The connection between the upper structure 3 and the lower structure 2 is widely made using a flange joint in which a flange 5 arranged at the upper end of the lower structure 2 is fastened to a flange 6 arranged around the entire lower end of the upper structure 3 using a number of bolts (see, for example, the patent literature).

[0006] As shown in Fig. 11, such an offshore wind turbine is assembled by first installing and stabilizing a floating or bottom-mounted substructure 2 made of a monopile or the like, and then connecting the lower end of the superstructure 3, which is suspended from a crane 8 mounted on a large crane ship 7, SEP ship, or the like, to the upper end of the substructure 2. The reference symbol 9 in the figure indicates the water surface.

[0007] At that time, the upper structure 3 is moved above the lower structure 2 while being suspended by a crane 8, and the flange 6 of the upper structure 3 is joined to the flange 5 of the lower structure 2 while fine-tuning the positions of the bolt holes of both flanges 5, 6, and then the joined flanges 5, 6 are fastened together with a number of bolts (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2007-138765 A [Patent Document 2] JP 2013-19207 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, in recent years, as offshore wind power generation equipment has become larger, the upper and lower structures that make up the equipment have also become larger, with many cases weighing more than 1,000 tons.With such large components, using conventional technology, there was a problem that when joining the flanges of the lower structure and the upper structure, it was difficult to adjust the positions of the bolt holes in both flanges to within a few millimeters.

[0010] More specifically, the superstructure suspended by the crane is essentially in a pendulum motion, and reaches its maximum speed when the bottom of the superstructure passes its lowest point. The kinetic energy at this time is estimated to be several tens of tonnes per metre in impulse, and suddenly suppressing this would generate an impact load, posing problems in terms of both structure and safety.

[0011] In particular, if the lower structure is a floating type, the water depth of the installation area is deep, and in the open ocean where SEP vessels cannot be used, both the floating lower structure and the work vessel that suspends the upper structure will sway, resulting in relative sway of several meters between the upper structure and the lower structure, and it is necessary to adjust the position of the above-mentioned bolt holes, which can make the work more difficult.

[0012] In view of these conventional problems, the present invention has been made with the aim of providing a method for assembling an offshore wind turbine generator that suppresses relative oscillation when joining the lower structure and the upper structure, thereby enabling efficient assembly work. [Means for solving the problem]

[0013] The feature of the invention described in claim 1 for solving the above-mentioned conventional problems is that in a method for assembling an offshore wind power generation system in which the lower end of an upper structure in a suspended state is connected to the upper end of a cylindrical lower structure of the offshore wind power generation system, the tips of each sway suppression wire paid out from a plurality of winches arranged at intervals circumferentially on the upper part of the lower structure are connected to a connector provided at the lower end of the upper structure, the winches are controlled so that the sway suppression wire is maintained in a taut state with a predetermined tension, and the upper structure is suspended down to above the lower structure while suppressing its swaying.

[0014] The feature of the invention described in claim 2 is that, in addition to the configuration of claim 1, the sway suppression wires unwound from at least one pair of the multiple winches arranged at positions that are linearly symmetrical in a predetermined diameter direction of the lower structure are connected to the connecting device so as to be cross-hitched with each other.

[0015] The feature of the invention described in claim 3 is that, in addition to the configuration of claim 1, at least a pair of sway control units, in which the multiple winches arranged in parallel are arranged in positions that are linearly symmetrical to each other in the specified diameter direction, are arranged so that the specified diameter directions are perpendicular to each other, and the sway suppression wires paid out from the multiple winches arranged in opposing positions are connected to the connecting device so that they are cross-hatched to each other.

[0016] The feature of the invention described in claim 4 is that, in addition to the configuration of claim 2 or 3, the sway suppression wire is unwound toward a connector provided at the lower end of the upper structure via a pulley arranged at the upper end of the lower structure so as to face the winch.

[0017] The invention described in claim 5 is characterized in that, in addition to the configuration of claim 1, a base end of a connecting wire is attached to a connecting device provided at the lower end of the upper structure, and after the upper structure is moved above the lower structure, a tip of the connecting wire is connected to a tip of the sway suppression wire via a connecting device. Effect of the Invention

[0018] The method of assembling an offshore wind turbine power generation equipment according to the present invention is provided with the configuration described in claim 1, and while allowing a certain degree of swaying of the upper structure suspended by the crane, it is possible to limit and suppress the swaying of the upper structure by continuously applying a load that is extremely small compared to the weight of the wind turbine itself, thereby significantly reducing the time required to adjust the position of the bolt holes in the flanges to be joined.

[0019] In addition, in the present invention, by providing the configurations described in claims 2 and 3, tension for suppressing swinging can be applied accurately in the swinging direction.

[0020] Furthermore, in the present invention, by providing the configuration described in claim 4, a sufficient length (stroke) of the sway suppression wire can be ensured, and by reducing the angle of the sway suppression wire, the dispersion of tension can be suppressed, and the tension can be applied efficiently.

[0021] Furthermore, in the present invention, by providing the configuration recited in claim 5, the wire connecting work can be simplified and the work can be performed efficiently. [Brief description of the drawings]

[0022] [Figure 1] FIG. 11 is a partially enlarged cross-sectional view showing the joint between the upper structure and the lower structure when the apparatus used in the assembly method for the offshore wind turbine power generation device according to the present invention is installed. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA of the same. [Diagram 3] FIG. 10 is a diagram showing the procedure of an assembly method for an offshore wind turbine generator according to the present invention, and is a partially enlarged cross-sectional view showing the state after the lower structure has been installed. [Figure 4] FIG. 11 is a partially enlarged cross-sectional view showing the state in which the upper structure suspended by a crane has been moved above the lower structure. [Diagram 5] FIG. 11 is a partially enlarged cross-sectional view showing a state in which the tip of the sway suppression wire is connected to a connector provided at the lower end of the upper structure. [Figure 6] FIG. 4 is a partially enlarged cross-sectional view showing the state of the upper structure being lowered. [Figure 7] FIG. 4 is a partially enlarged cross-sectional view showing a state in which the lower end of the upper structure is in contact with a shoe on the lower structure. [Figure 8] FIG. 4 is a partially enlarged cross-sectional view showing the state in which the upper and lower flanges are joined together. [Figure 9] FIG. 4 is a partially enlarged cross-sectional view showing the state in which the flanges are joined together by bolts. [Figure 10] FIG. 4 is a partially enlarged cross-sectional view showing the state in which the sway suppression device of the above has been removed. [Figure 11] FIG. 4 is a partially enlarged side view showing the assembly work state of the offshore wind turbine generator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Next, an embodiment of an assembly method for an offshore wind turbine 1 according to the present invention will be described based on the embodiment shown in Figures 1 to 10. Note that the same components as those in the above-mentioned conventional example will be described with the same reference numerals.

[0024] An offshore wind power generation device 1 comprises a cylindrical lower structure 2 which is installed with its upper end protruding above the water, a tower-shaped upper structure 3 whose lower end is connected to the upper end of the lower structure 2, and wind power generation equipment 4 consisting of a wind turbine (nacelle / rotor) supported on the upper end of the upper structure 3. As shown in Figure 11, after the lower structure 2 is installed and stabilized, the lower end of the upper structure 3 is connected to the upper end of the lower structure 2 while being suspended from a crane 8 mounted on a large crane ship 7, SEP ship, or the like, and the device is assembled.

[0025] The lower structure 2 has a brim-like flange 5 that protrudes outward from the upper end of the cylindrical shape, and in the case of a floating type, for example, it is composed of a spar-type floating section that floats upright with its upper part protruding above the water, and in the case of a fixed-bottom type, it is composed of a monopile or the like installed on the bottom of the water.

[0026] Furthermore, the form of the lower structure 2 may be any as long as it has a cylindrical portion to which the upper structure 3 is joined, and in the case of a floating type, it may be the spar type described above, as well as a pontoon type, semi-submersible type, or TLP type, and in the case of a fixed-bottom type, it may be a monopile type, as well as a tripile, jacket type, etc.

[0027] The upper structure 3 is formed in a tapered cylindrical shape with a smaller diameter on the upper end side, and is provided with a brim-like flange 6 that protrudes outward at the lower end.

[0028] In addition, the upper structure 3 has connectors 11, 11 . . . fixed at predetermined positions on the inner circumferential surface of the lower end portion to which the ends of sway suppression wires 10, which will be described later, are connected.

[0029] In this embodiment, an example is described in which the wind power generation equipment 4 consisting of a wind turbine (nacelle / rotor) etc. is attached to the upper end and then connected to the lower structure 2, but the wind power generation equipment 4 may also be attached after the upper structure 3 is connected to the lower structure 2.

[0030] The connection between the upper structure 3 and the lower structure 2 is made, for example, by flange jointing in which a flange 5 arranged at the upper end of the lower structure 2 and a flange 6 arranged at the lower end of the upper structure 3 are fastened together by a plurality of bolts 12, 12.... Note that the means for connecting the upper structure 3 and the lower structure 2 is not limited to the flange jointing described above, and other connection means may be used.

[0031] A specific method for assembling such an offshore wind turbine generator 1 will be described in detail with reference to FIGS.

[0032] As a preliminary preparation, the base ends of connecting wires 13, 13... having a certain length are attached to the connectors 11, 11... provided at the lower end of the upper structure 3, and the other ends are fixed to the lower end of the upper structure 3 as free ends or in a bundled state so that they can be easily released.

[0033] On the other hand, after the lower structure 2 has been installed and stabilized using a well-known method depending on whether it is a floating type or a bottom-mounted type, a pair of swing control units 14, 14 are installed on the upper inner circumference of the lower structure 2 at positions that are linearly symmetrical in a specified diameter direction of the lower structure 2 and in directions perpendicular to each other, as shown in Figure 2.

[0034] As shown in Figures 1 and 2, each swing control unit 14, 14 is configured with multiple (in this embodiment, a pair of) winches 15, 15 arranged in parallel at intervals around the circumferential direction of the lower structure 2, and is positioned so that they are linearly symmetrical to each other in a predetermined diameter direction of the lower structure 2, and both swing control units 14, 14 are arranged so that the predetermined diameter directions are perpendicular to each other, and each winch 15, 15... is arranged to form a grid pattern.

[0035] A mounting base 16 is fixed to a predetermined position on the upper inner peripheral surface of the lower structure 2 by welding, bolting, or the like, and the winches 15, 15... are placed and fixed on the mounting base 16. It is preferable that the mounting base 16 is attached to a predetermined position before the lower structure 2 is installed.

[0036] These winches 15, 15... use electric winches with servos, and use a back tension function to pay out the sway suppression wire 10 when a predetermined tension is exceeded, and to wind up the sway suppression wire 10 when it bends and falls below the predetermined tension, so that the sway suppression wire 10 can be controlled so that it always has a constant tension.

[0037] In addition, for the winches 15, 15..., those with braking capabilities that are approximately 1 / 100 of the weight of the upper structure 3 and the wind turbine equipment are selected. For example, in the case of a 15 MW class offshore wind power generation device 1, the braking force is set to 20 tons taking into account the horizontal force generated at the maximum swing amplitude, and a 15-ton winch that satisfies this requirement is used.

[0038] The sway suppression wire 10 is made of a rope or wire of a thickness capable of withstanding the horizontal force generated when the upper structure 3 swings at its maximum swing range. For example, a rope with a diameter of approximately 60 mm is used, and a wire with a diameter of approximately 40 mm is used.

[0039] In addition, pulleys 17 are arranged at the upper end of the lower structure 2 so as to face each winch 15, 15..., and the sway suppression wire 10 paid out from the winches 15, 15... is folded back toward the mounting position of the upper structure 3 via these pulleys 17.

[0040] The pulleys 17 are arranged at intervals from one another so that the sway suppression wires 10 paid out from the winches 15, 15 . . . do not cross each other.

[0041] Furthermore, shoe seats (shoes) 18, 18... are installed at predetermined positions on the upper surface of the flange of the lower structure 2. At least four shoe seats (shoes) 18, 18... are installed at equal intervals in the circumferential direction.

[0042] The height of the shoes 18, 18... is set to about half the vertical oscillation (single amplitude) so as to prevent the suspension load of the crane 8 from being suddenly released after the lower end of the upper structure 3 lands on the shoes 18, 18....

[0043] Next, as shown in FIG. 4, the upper structure 3 is suspended by a crane 8 of a crane ship or the like, moved to above the installed lower structure 2, and stopped once at a predetermined height h.

[0044] The specified height h is set so that the angle θ formed by the pulley 17 and the connectors 11, 11... with the sway suppression wire 10 provided on the upper structure 3 at a position opposite the boundary of the specified diameter is 15 to 45 degrees.

[0045] Specifically, it is desirable to set the angle θ between the pulleys 17, 17... and the connectors 11, 11... located at a position facing the boundary of a predetermined diameter of the lower structure 3 to 15 degrees to 45 degrees or less. By setting the angle θ to 15 degrees or more, a sufficient distance can be secured between the lower end of the upper structure 3 and the upper end of the lower structure 2, and danger can be prevented for the worker who connects the sway suppression wire 10. In addition, by setting the angle θ between the pulleys 17 and the connectors 11, 11... located at a position facing the boundary of a predetermined diameter, the pulling force of the winches 15, 15... does not act in the vertical direction, and the pulling force can be exerted to control the horizontal swing of the upper structure 3.

[0046] Furthermore, the specified height h is not limited to the above-mentioned embodiment, and can be set appropriately depending on the scale of the offshore wind power generation device 1 (diameter of the upper structure 3 and lower structure 2), etc., and it is preferable to ensure at least approximately 3 m from the standpoint of ensuring safety.

[0047] Next, the connecting wires 13, 13... with their tips connected to each of the connectors 11, 11... on the upper structure 3 are hung downward, and the sway suppression wire 10 is paid out diagonally forward from each winch 15, 15..., and a predetermined diameter of the wire is wrapped around a pulley 17 located opposite the boundary, folded back, and pulled out.

[0048] Then, as shown in Figure 5, the tip of the sway suppression wire 10 unwound through the pulley 17 is connected to the tip of the connecting wires 13, 13... which are connected to connecting devices 11, 11... located at a position opposite the boundary of the pulley 17 and a specified diameter by a coupling device 19, and the sway suppression wire 10 is connected to the corresponding connecting devices 11, 11... via the connecting wires 13, 13...

[0049] In addition, by winding up the sway suppression wire 10 with the winches 15, 15... and applying a predetermined tension to the sway suppression wire 10, the sway suppression wire 10 paid out from the winches 15, 15... at opposing positions is connected to the upper structure 3 so that it is cross-hitched between the winches 15, 15... and the pulley 17, and between the pulley 17 and the connectors 11, 11...

[0050] Next, as shown in Figures 6 to 8, the upper structure 3 suspended by the crane 8 is lowered to a position where the lower end of the upper structure 3 contacts the upper ends of the shoes 18, 18... installed at the upper end of the lower structure 2.

[0051] At that time, the sway suppression wire 10 is wound up by the winches 15, 15... in synchronization with the descent speed of the upper structure 3, and the back tension function operates to pay out the sway suppression wire 10 when a predetermined tension is exceeded, and to wind up the sway suppression wire 10 when it bends and falls below the predetermined tension, thereby controlling the sway suppression wire 10 to always maintain a constant tension.

[0052] The upper structure 3, suspended by the crane 8, is basically in a state of pendulum motion. For example, when assembling a 15 MW offshore wind power generation device 1 under conditions of a wave height of 1 m and a wave period of 8 seconds, swaying of about 2 m occurs at the lower end of the upper structure 3, but the swaying of the upper structure 3 is suppressed by always controlling the sway suppression wire 10 to maintain a constant tension.

[0053] Furthermore, in the event of a large force being generated by a sudden wave or the like, the brakes of the winches 15, 15... are activated to prevent the upper structure 3 from swinging suddenly, thereby making it possible to suppress the swinging of the upper structure 3.

[0054] Furthermore, the upper structure 3 is expected to reach its maximum speed when its lower end passes its lowest point, and the kinetic energy is expected to be several tens of t·m in impulse.

[0055] On the other hand, since the distance from the top of the crane 8 of the crane ship to the bottom of the superstructure 3 exceeds 100 m, even when the maximum amplitude (several meters) occurs, the inclination of the superstructure 3 will only be about 1 degree, which is not a cause for concern.

[0056] Therefore, the horizontal force generated when the upper structure 3 is tilted to its maximum (maximum swing amplitude) is approximately 20 to 30 tons, which is two orders of magnitude lower than the weight of the wind turbine equipment (nacelle + tower) of a 15 MW-class facility (2,000 to 3,000 tons), and can be handled by the brakes of the winches 15, 15...

[0057] Next, with the lower end of the upper structure 3 in contact with the shoes 18, 18..., the back tension function operates to pay out the sway-suppressing wire 10 when a predetermined tension is exceeded, and to wind up the sway-suppressing wire 10 when it bends and falls below the predetermined tension, thereby controlling the sway-suppressing wire 10 to always be at a constant tension, while fine-tuning the position of the upper structure 3 and aligning the bolt hole positions of the flange 6 of the upper structure 3 and the flange 5 of the lower structure 2. Note that after the lower end of the upper structure 3 comes into contact with the footrests 18, 18..., the set predetermined tension of the sway-suppressing wire 10 may be changed as appropriate, taking into consideration that the load changes when the lower end of the upper structure 3 comes into contact with the footrests 18, 18....

[0058] At that time, horizontal oscillation is suppressed by the oscillation suppression wire 10, and since the lower end of the upper structure 3 is in contact with the shoes 18, 18..., the shoes 18, 18... absorb the oscillation in the vertical direction, thereby suppressing the oscillation.

[0059] Then, after the alignment of both flanges 5, 6 is completed, as shown in FIG. 9, the upper structure 3 is further lowered and both flanges 5, 6 are joined together, and then the both flanges 5, 6 are joined together by bolts 12, 12.

[0060] Finally, as shown in FIG. 10, a small work crane (not shown) installed inside or above the upper structure 3 is used to remove the winches 15, 15..., pulley 17, sway suppression wire 10, etc., and the work is completed.

[0061] In the above-mentioned embodiment, the sway suppression wire 10 paid out from the winches 15, 15... is looped around the pulley 17, and the tip of the sway suppression wire 10 paid out via the pulley 17 is connected to the connectors 11, 11... which are located opposite the boundary and a specified diameter from the pulley 17. However, if the angle between the winches 15, 15... and the sway suppression wire 10 can be reduced, the pulley 17 may not be used, and the tip of the sway suppression wire 10 paid out from the winches 15, 15... may be connected to the connectors 11, 11... which are located opposite the boundary and a specified diameter from the winches 15, 15....

[0062] In addition, in the above-mentioned embodiment, a case has been described in which the connecting wires 13, 13... are attached to the connecting parts 11, 11... of the upper structure 3 in advance, but the tip of the sway suppression wire 10 may be directly connected to the connecting parts 11, 11... without using the connecting wires 13, 13....

[0063] Furthermore, the arrangement of the winches 15, 15... is not limited to the above-mentioned grid shape, and may be arranged, for example, at equal intervals in the circumferential direction of the lower structure 2 so that the sway suppression wires 10, 10... do not become entangled. Note that by increasing the number of installed winches 15, winches with smaller winch specifications can be used, making installation easier. [Explanation of symbols]

[0064] 1. Offshore wind power generation equipment 2. Undercarriage 3 Superstructure 4 Windmill equipment 5 Flange 6 Flange 7 Hoist ship 8. Crane 9 water surface 10. Wire rod for suppressing oscillation 11 Connectors 12 Volts 13 Connecting Wires 14. Sway suppression unit 15 Winch 16 Mounting stand 17 Pulley 18 Kutsuza 19 Connectors

Claims

1. A method for assembling an offshore wind turbine in which a lower end of a suspended upper structure is connected to an upper end of a cylindrical lower structure of the offshore wind turbine, a plurality of winches arranged at intervals in the circumferential direction on the upper portion of the lower structure are used to pay out respective ends of the sway suppression wires, the ends of the wires being connected to a connector provided at a lower end portion of the upper structure; A method for assembling an offshore wind power generation device, characterized in that the winch is controlled so that the sway suppression wire is maintained in a taut state with a predetermined tension, and the upper structure is lowered onto the lower structure while suppressing the swaying of the upper structure.

2. The method for assembling an offshore wind power generation device as described in claim 1, wherein the sway suppression wires unwound from at least one pair of the multiple winches arranged at positions that are linearly symmetrical in a predetermined diameter direction of the lower structure are connected to the connector so as to be cross-hatched with each other.

3. A method for assembling an offshore wind power generation device as described in claim 1, wherein at least a pair of sway control units, in which the multiple winches arranged in parallel are arranged in positions that are linearly symmetrical to each other in the specified diameter direction, are arranged so that the specified diameter directions are perpendicular to each other, and the sway suppression wires unwound from the multiple winches arranged in opposing positions are connected to the connector so that they are cross-hatched to each other.

4. A method for assembling an offshore wind power generation device as described in claim 2 or 3, wherein the sway suppression wire is unwound toward a connector provided at the lower end of the upper structure via a pulley arranged at the upper end of the lower structure opposite the winch.

5. 2. A method for assembling an offshore wind power generation device as described in claim 1, in which a base end of a connecting wire is attached to a connecting device provided at the lower end of the upper structure, and after the upper structure is moved above the lower structure, the tip of the connecting wire is connected to the tip of the sway suppression wire via a connecting device.

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