JP6130207B2 - Floating structure for offshore wind power generation - Google Patents

Description

  The present invention relates to a floating structure used for floating offshore wind power generation, and more particularly to a floating structure having a mechanism for suppressing fluctuations caused by waves.

  Conventionally, as a floating structure for floating offshore wind power generation, types such as a semi-sub type, a TLP (tension mooring) type, and a spar type as shown in FIG. 4 are known. Since vibration and shaking are a cause of failure for wind generators composed of various devices, in floating offshore wind power generation, how to suppress vibration and shaking of floating structures used as the foundation of wind power generators Is a more important issue than before.

  The semi-sub type and TLP type use a semi-submersible type floating body with a small waterline area to reduce the shaking caused by waves (vertical shaking, rolling, rotation), especially the TLP type forcing the floating body into water. It is known as a method that can reduce the up and down motion that cannot be handled by the semi-sub type because a large buoyancy and mooring force are applied by pulling in and buoyancy and mooring force always act even if a load fluctuates due to waves.

  For example, Patent Documents 1 to 9 have been proposed as conventional techniques related to the semi-sub system, and for example, Patent Documents 10 to 14 have been proposed for the TLP system, and for example, Patent Documents 15 to 20 have been proposed for the spar system. ing.

JP 2010-247646 A JP 2010-216273 A JP 2009-85167 A JP 2007-263077 A Japanese Patent Laid-Open No. 2005-351087 JP 2004-225859 A JP 2004-36517 A JP 2002-285951 A JP 2002-285951 A JP 2010-234965 A JP 2010-64649 A JP 2010-64648 A JP 2010-30379 A JP 2010-18129 A JP 2010-223114 A JP 2010-223113 A JP 2009-248792 A JP 2007-518912 A JP 2003-343447 A JP 2002-188557 A

  In the above TLP type floating structure, the natural frequency of the floating body and mooring system is designed to remove the wave period (about 4-18 seconds), especially designed to be 4 seconds or less, avoiding the long period side where the wave force is large. Is done. However, the number of rotations of the rotor of a wind power generator is usually about 10 to 50 rotations / minute (period is about 1 to 6 seconds), and there is a possibility of resonating in accordance with the natural frequency of the floating body and mooring system. When a wind power generator is mounted on a floating structure, a countermeasure against resonance is required.

  In addition, additional mass force and wave-damping force act on the floating structure that is swaying, but in the vertical shaking mode, the change of the waterline area is small and the effect of wave-damping force is poor. Even if the resonance is avoided, there is a problem that it is difficult to settle.

  The present invention has been made in view of the above, and an object of the present invention is to provide a floating structure for offshore wind power generation that can suppress the vibration generated by the wind power generator and can reduce ups and downs caused by waves. To do.

To solve the problems described above and achieve the object, offshore wind power generation floating construction according to the present onset Ming, a floating structure for use as the basis of a wind power generator in offshore wind, the floating structure A tension mooring line that connects and anchors the buoyancy center of an object and an anchor and tensions the floating structure, and is interposed between the floating structure and the tension mooring line to attenuate the vertical swing of the floating structure. A vibration damping mechanism, an operating state interposed between the vibration damping mechanism and the tension mooring line to engage and integrate the vibration damping mechanism and the tension mooring line, and the vibration damping mechanism, A stopper mechanism that can be switched to a non-operating state in which the tension mooring line is disconnected and the integration is released, and the sway damping mechanism and the tension mooring line are integrated with the stopper mechanism in an operating state in normal times. Turn into On the other hand, in the event of an emergency such as a storm wave or an earthquake, the stopper mechanism can be deactivated to separate the sway damping mechanism from the tension mooring line, and the tension force of the tension mooring line can be adjusted according to the applied load characterized in that the.

Moreover, offshore wind power generation floating construction according to the present onset bright is the invention described above, and further comprising the natural frequency adjusting mechanism for adjusting the natural frequency of the floating body and mooring system.

Moreover, offshore wind power generation floating construction according to the present onset bright is the invention described above, and further comprising a catenary mooring for anchoring the floating structure in catenary formulas.

  According to the present invention, a floating structure used as a foundation of a wind power generator in offshore wind power generation, wherein the buoyancy center of the floating structure and an anchor are connected to tension and moor the floating structure. A floating body such as a semi-sub type or a TLP type that is excellent in seaworthiness because it includes a cable and a vibration damping mechanism that is interposed between the floating structure and the tension mooring line and attenuates the vertical swing of the floating structure. It is possible to suppress the vibration force from the wind power generator, which is difficult to cope with even with the structure, and to reduce the vertical swing of the floating structure due to the waves. The resonance countermeasure and the wave sway countermeasure can provide an effect of providing a floating offshore wind power generation system in which equipment maintenance of the wind power generator is ensured. In addition, according to the present invention, there is a possibility that an existing on-shore wind power generator can be diverted with measures to take measures against salt damage, and it is superior in cost competitiveness to other types of floating offshore wind power generation systems. It is thought that it becomes.

  In addition, according to another configuration of the present invention, since the natural frequency adjusting mechanism for adjusting the natural frequency of the floating body and the mooring system is further provided, the natural frequency of the floating body and the mooring system is set to By adjusting the frequency so as not to coincide with the natural frequency, there is an effect that the resonance phenomenon can be more reliably prevented.

  Further, according to another configuration of the present invention, an operation state that is interposed between the oscillation damping mechanism and the tension mooring line, and engages and integrates the oscillation damping mechanism and the tension mooring line; , Further comprising a stopper mechanism that can be switched to a non-operating state in which the sway damping mechanism and the tension mooring line are separated to release the integration, and the sway damping mechanism and the In the event of an emergency such as a storm wave or an earthquake, the tension mooring line is integrated, and the stopper mechanism is deactivated to separate the sway damping mechanism and the tension mooring line, and the tension mooring line depends on the applied load. The tension of the mooring line is adjustable.

  If a tension mooring line that is constantly subjected to a large tension is subject to excessive fluctuating loads during storm waves or earthquakes, there is a risk of damage and other problems.However, according to the above configuration, In the event of an earthquake, the tension of the tension mooring line can be easily relaxed to avoid the risk of damage, and when the possibility of danger disappears, the tension can be restored and the function of the sway damping mechanism can be exhibited again. As a result, there is an effect that it is possible to provide a floating offshore wind power generation system that is suitable for the characteristics of the Japanese sea area where typhoons and earthquakes are very common.

  Moreover, according to the other structure of this invention, since the catenary mooring line which moored the said floating structure by catenary type is further provided, there exists an effect that a floating structure can be prevented from drifting.

FIG. 1 is a schematic view showing an example of a floating structure for offshore wind power generation according to the present invention. FIG. 2 is an enlarged view (normal time) of portion A in FIG. FIG. 3 is an enlarged view of portion A in FIG. 1 (when a storm wave or an earthquake occurs). FIG. 4 is a diagram illustrating a conventional floating structure for floating offshore wind power generation.

  Hereinafter, embodiments of a floating structure for offshore wind power generation according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  As shown in FIG. 1, a floating structure 10 for offshore wind power generation according to the present invention is a floating structure used as a foundation of a wind power generator 12 in offshore wind power generation, and is located at a buoyancy center C of the floating structure 10. A tension mooring line 14 and a damper 16 (sway damping mechanism) are provided.

  The floating structure 10 is a semi-submerged floating body whose lower part is submerged under the seawater surface 18, and includes a central floating body 20, an outer floating body 22, and a connecting member 24 that connects these lower portions. Although the planar positional relationship between the central floating body 20 and the outer floating body 22 is not shown here, a plurality of (for example, three) outer floating bodies 22 are arranged at equal intervals in the circumferential direction on the circumference centering on the central floating body 20. The central floating body 20 is positioned at the buoyancy center C of the floating structure 10.

  Further, in order to prevent the floating structure 10 from drifting, the floating structure 10 is moored in a catenary manner by a catenary mooring line 26 connected to the lower end of the outer floating body 22.

  As described above, the semi-submersible floating body used in the semi-sub type or the TLP type is used as the floating structure 10 to reduce the rolling / rotation caused by the waves, and the tension mooring line 14 used in the TLP type is used as the floating structure 10. By arranging it at the buoyancy center C, the pitching caused by waves is reduced.

  The central floating body 20 and the outer floating body 22 are constituted by cylindrical members, and the outer floating body 22 can adjust buoyancy by injecting ballast water therein. In addition to this, the buoyancy may be adjusted by injecting ballast water into the central floating body 20. The connecting member 24 is composed of a rod-shaped member, and can be composed of a hollow or solid member into which ballast water can be injected.

  A tower 36 is erected on the upper surface of the central floating body 20, and a wind turbine 12 including a windmill 38 and a rotor is attached to the top of the tower 36. Further, the central floating body 20 is provided with a through hole 28 penetrating the upper and lower surfaces along the buoyancy center C, and the tension mooring line 14 is inserted therethrough.

  The tension mooring line 14 extends from the winding drum 30 installed at the lower end of the tower 36 through the through hole 28, extends vertically downward along the buoyancy center C, and is connected to an anchor 34 sunk in the seabed 32. The floating structure 10 is moored using the tension generated by the buoyancy of the structure 10.

  Further, a concave damper chamber 40 (portion A in FIG. 1) is formed inside the lower end of the tower 36.

  FIG. 2 shows an enlarged view (normal time) of portion A of FIG. 1, and FIG. 3 shows an enlarged view of portion A of FIG. 1 (during storm waves and earthquakes).

  As shown in FIG. 2 or FIG. 3, the damper chamber 40 is provided with a damper 16 (a vibration damping mechanism), a spring 42 (a natural frequency adjusting mechanism), and a stopper mechanism 44. Further, an opening 46 for guiding the tension mooring cable 14 to the upper winding drum 30 is provided on the upper surface of the damper chamber 40.

  The damper 16 is a vibration damping mechanism for damping the vertical swing of the floating structure 10, and is interposed between the tower 36 (that is, the central floating body 20 connected thereto) and the tension mooring line 14. The damper 16 is a hydraulic oil damper including a cylinder 16a and a piston rod 16b. In the present embodiment, the damper 16 is provided on the left and right sides of the tension mooring line 14.

  By arranging the damper 16 on the tension mooring line 14 in this way, the vertical swing of the floating structure 10 can be attenuated. In this embodiment, the damper 16 is described as the vibration damping mechanism. However, the present invention is not limited to this, and any mechanism can be used as long as the mechanism can attenuate the vertical swing of the floating structure 10 due to waves. May be.

  The spring 42 is a natural frequency adjusting mechanism for adjusting the natural frequency of the floating body and the mooring system, and is interposed between the cylinder 16 a of the damper 16 and the upper surface of the damper chamber 40. Thus, while providing the spring 42 between the tension mooring line 14 and the floating structure 10, the natural frequency of the floating body and the mooring system is adjusted so as not to coincide with the natural frequency of the rotor of the wind power generator 12. Thus, the resonance phenomenon with the rotor of the wind power generator 12 can be more reliably prevented. Instead of providing the spring 42, resonance may be prevented by adjusting the natural frequency of the floating body / tethering system by reducing the rigidity of the tension mooring cable 14 itself.

  The stopper mechanism 44 includes a base 44a and a pad 44b, and is interposed between the damper 16 and the tension mooring line 14. In this embodiment, the stopper mechanism 44 is provided on the left and right sides of the tension mooring line 14. The stopper mechanism 44 can be switched between an operation state in which the damper 16 and the tension mooring line 14 are engaged and integrated, and a non-operation state in which the damper 16 and the tension mooring line 14 are disconnected and the integration is released. is there.

  More specifically, each base 44a of the stopper mechanism 44 is connected to the piston rod 16b of the damper 16 above it. In the operating state of the stopper mechanism 44, as shown in FIG. 2, the pistons 44 of the damper 16 are pressed by pressing the pads 44b arranged opposite to the inner ends on the base 44a to sandwich the tension mooring line 14 from the left and right. 16b and the tension mooring line 14 are engaged. On the other hand, in the non-actuated state, as shown in FIG. 3, the pad 44b is pulled away from the tension mooring line 14 to disengage the damper 16 from the piston rod 16b.

  In the above configuration, at the normal time, as shown in FIG. 2, the damper mechanism 16 and the tension mooring line 14 are integrated with the stopper mechanism 44 in an activated state. In this state, the vertical shaking of the floating structure 10 due to the waves is transmitted to the tension mooring line 14 via the spring 42 and the damper 16 via the base 44b and the pad 44a. In this case, the vertical swing of the floating structure 10 is attenuated by the function of the damper 16.

  In an emergency such as a storm wave or an earthquake, the stopper mechanism 44 is deactivated and the damper 16 and the tension mooring line 14 are disconnected as shown in FIG. Then, the tension force of the tension mooring line 14 is adjusted by the rotation of the winding drum 30 according to the swaying load acting on the floating structure 10.

  The tension mooring line 14 to which a large tension is always applied may cause damage such as breakage during a storm wave or an earthquake in which an excessively variable load is applied. However, according to the present invention, during a storm wave or an earthquake. By disabling the stopper mechanism 44, the tension force of the tension mooring line 14 can be easily relaxed and the risk of damage can be avoided. After that, when the possibility of danger disappears, the function of the damper 16 can be exhibited again by restoring the tension of the tension mooring line 14 by operating the stopper mechanism 44. As a result, it is possible to provide a floating offshore wind power generation system that is suitable for the characteristics of Japan's marine areas, where typhoons and earthquakes are very common.

  When returning to a normal floating body / tethered state, for example, seawater is injected into the internal ballast of the outer floating body 22 or the central floating body 20 by a pump to lower the draft, and after the stopper mechanism 44 is activated, the ballast water May be drained to the outside by a pump so that tension is applied to the tension mooring line 14.

  For this reason, according to the floating structure for offshore wind power generation according to the present invention, the exciting force from the wind power generator that is difficult to cope with even with a floating structure such as a semi-sub type or a TLP type having excellent seaworthiness. While being able to suppress, the up-and-down swing of the floating structure by a wave can be reduced. A floating offshore wind power generation system in which equipment maintenance of the wind power generator is ensured can be provided by the countermeasures against resonance and wave vibration.

  In addition, the tension mooring line can be easily relaxed during storm waves or earthquakes to avoid the risk of damage, and when the possibility of danger disappears, the tension can be restored and the function of the sway damping mechanism can be demonstrated again. . As a result, it is possible to provide a floating offshore wind power generation system that is suitable for the characteristics of Japan's marine areas, where typhoons and earthquakes are very common.

  In addition, the floating offshore wind power generation requires the development of a wind power generator that is resistant to shaking, but according to the present invention, the existing on-shore wind power generator can be diverted with measures to prevent salt damage. There is a possibility that it will be possible, and it will be advantageous in cost competitiveness over other forms of floating offshore wind power generation systems.

  As described above, according to the present invention, a floating structure used as a foundation of a wind power generator in offshore wind power generation, which connects a buoyancy center of the floating structure and an anchor to tension the floating structure. A tension mooring line to be moored, and a swing damping mechanism that is interposed between the floating structure and the tension mooring line to attenuate the vertical swing of the floating structure. It is possible to suppress the vibration force from a wind power generator that is difficult to cope with even with a floating structure such as a TLP type or the like, and to reduce the vertical swing of the floating structure due to waves. A floating offshore wind power generation system in which equipment maintenance of the wind power generator is ensured can be provided by the countermeasures against resonance and wave vibration. In addition, according to the present invention, there is a possibility that an existing on-shore wind power generator can be diverted with measures to take measures against salt damage, and it is superior in cost competitiveness to other types of floating offshore wind power generation systems. It is thought that it becomes.

  In addition, according to another configuration of the present invention, since the natural frequency adjusting mechanism for adjusting the natural frequency of the floating body and the mooring system is further provided, the natural frequency of the floating body and the mooring system is set to By adjusting so as not to coincide with the natural frequency, the resonance phenomenon can be prevented more reliably.

  Further, according to another configuration of the present invention, an operation state that is interposed between the oscillation damping mechanism and the tension mooring line, and engages and integrates the oscillation damping mechanism and the tension mooring line; , Further comprising a stopper mechanism that can be switched to a non-operating state in which the sway damping mechanism and the tension mooring line are separated to release the integration, and the sway damping mechanism and the In the event of an emergency such as a storm wave or an earthquake, the tension mooring line is integrated, and the stopper mechanism is deactivated to separate the sway damping mechanism and the tension mooring line, and the tension mooring line depends on the applied load. The tension of the mooring line is adjustable.

  If a tension mooring line that is constantly subjected to a large tension is subject to excessive fluctuating loads during storm waves or earthquakes, there is a risk of damage and other problems.However, according to the above configuration, In the event of an earthquake, the tension of the tension mooring line can be easily relaxed to avoid the risk of damage, and when the possibility of danger disappears, the tension can be restored and the function of the sway damping mechanism can be exhibited again. As a result, it is possible to provide a floating offshore wind power generation system that is suitable for the characteristics of Japan's marine areas, where typhoons and earthquakes are very common.

  Moreover, according to the other structure of this invention, since the catenary mooring line which moored the said floating structure by catenary type is further provided, it can prevent that a floating structure drifts.

  As described above, the floating structure for offshore wind power generation according to the present invention is useful for a floating structure used by floating on the ocean as a foundation of a wind power generator in a floating offshore wind power generation system, It is suitable for suppressing vibrations from wind power generators, which are difficult to handle even with excellent floating structures such as the semi-sub type and TLP type, and to reduce ups and downs caused by waves.

10 Floating structure for offshore wind power generation (floating structure)
12 Wind power generator 14 Tension mooring line 16 Damper (sway damping mechanism)
16a cylinder 16b piston rod 18 sea surface 20 central floating body 22 outer floating body 24 connecting member 26 catenary mooring cable 28 through hole 30 winding drum 32 seabed 34 anchor 36 tower 38 windmill 40 damper chamber 42 spring (natural frequency adjustment mechanism)
44 Stopper mechanism 44a Base 44b Pad 46 Opening C Buoyancy center

Claims (3)

A floating structure used as the foundation of a wind power generator in offshore wind power generation,
A tension mooring line connecting the anchor of the buoyancy of the floating structure and an anchor, and tensioning and mooring the floating structure;
A vibration damping mechanism that is interposed between the floating structure and the tension mooring line and attenuates the vertical swing of the floating structure ;
An operation state that is interposed between the oscillation damping mechanism and the tension mooring line and engages and integrates the oscillation damping mechanism and the tension mooring line; and the oscillation damping mechanism and the tension mooring line. A stopper mechanism that can be switched to a non-operating state of separating and releasing the integration,
In the normal time, the stopper mechanism is in an activated state to integrate the sway damping mechanism and the tension mooring line,
In an emergency such as a storm wave or an earthquake, the stopper mechanism is deactivated to separate the sway damping mechanism and the tension mooring line so that the tension force of the tension mooring line can be adjusted according to the applied load. A floating structure for offshore wind power generation.   The floating structure for offshore wind power generation according to claim 1, further comprising a natural frequency adjusting mechanism for adjusting the natural frequency of the floating body and the mooring system. The floating structure of offshore wind power generation floating structure according to claim 1 or 2, further comprising a catenary mooring lines to anchor in catenary type.

Images