• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a floating support structure (10) for an offshore wind turbine, comprising a float (12) intended to be partially immersed and on which a wind turbine mast is intended to be assembled, and a counterweight connected to the float and intended to be assembled to be immersed under the float, the float comprising a main structure (18) of toric or polygonal shape with at least five sides, a central tubular structure (26) having a diameter adapted to receive the mast of the wind turbine and comprising a section adapted to be ballasted in order to adjust the float water line, a first series of horizontal struts (28) distributed about a vertical axis and connecting the main structure to the central structure, and a second series of oblique struts (30). ) distributed around a vertical axis (YY) and connecting the main structure to the central structure forming an angle of between 15 ° and 60 ° with the horizontal braces (28).
    公开号:FR3074138A1
    申请号:FR1761342
    申请日:2017-11-29
    公开日:2019-05-31
    发明作者:Christophe Colmard；Paul Franc；Jean-Baptiste Le Clezio；Frederic Gentil；Thierry DELAHAYE
    申请人:Saipem SA；
    IPC主号:
    专利说明:

    Title of invention
    Floating support structure for offshore wind turbines and method of installing a wind turbine provided with such a support structure
    Invention background
    The present invention relates to the general field of offshore wind turbines, that is to say those located offshore, and more particularly to floating support structures for floating offshore wind turbines. The invention also relates to a method of installing an offshore wind turbine provided with such a support structure.
    The purpose of an offshore wind turbine is to use wind energy to generate electricity using a turbine and an electric generator. There are two main types of offshore wind turbines: fixed wind turbines which are installed on the seabed (at shallow depths typically less than 50m), and floating wind turbines which offer the advantage of being able to be built on land and installed in areas where the depth of the seabed typically exceeds 50m.
    Floating wind turbines comprise a turbine generally formed by a motor with several rotary blades with a horizontal axis and an electric generator coupled to the motor, the motor and the generator being fixed to an upper end of a vertical mast (or pylon). The lower end of the mast is mounted on a floating support structure.
    There are four main families of floating support structure for offshore wind turbines: barges, semi-submersible platforms, platforms on stretched legs (or TLP platforms for “Tension-Leg Platform”), and “spar” platforms. that is to say platforms with submerged foundation and stabilized ballast which are provided with catenary anchors making it possible to fix the wind turbine by hanging on the seabed. Among these families, “spar” platforms have a relatively simple structure and are based on the use of manufacturing and installation technologies which are widely proven.
    We can refer in particular to the publication WO 2005/021961 which describes an example of embodiment of a “spar” platform. Publication WO 2006/121337 gives the details of an anchoring system for such a “spar” platform, while publication WO 2006/132539 relates to a method of installing this platform at sea.
    Spar platforms nevertheless have a number of drawbacks which greatly limit their usability in the field of offshore wind power. For a high power wind turbine, it is necessary to install the wind turbine to have a minimum depth of the order of a hundred meters to deploy a "spar" platform. More generally, it is necessary to have a deep zone and with relatively calm sea conditions to manage the critical phases that are the reversal of the platform from the horizontal position to the vertical position, the ballasting of the platform, and the assembly of the turbine over the platform. In addition, the use of “spar” platforms requires the use of large capacity crane boats which are rare and expensive to install wind turbines on offshore platforms. In addition, “spar” platforms have a large drag in water which limits the speed of movement of these platforms in the case of towing.
    These drawbacks of spar platforms limit the installation of wind turbines in areas with a fjord as a logistics base, which in practice is found in few places in the world, except in Norway. In addition, the costs achievable by platforms (due in particular to the very large quantity of steel compared to the flotation requirements) are limited to high values.
    Furthermore, the stability of a floating wind turbine can be broken down into a static stability problem and a dynamic stability problem. The problem of dynamic stability stems from non-constant forces over time, which exert a destabilizing torque for the structure, inducing movement. These are linked to fluctuations in wind speed on the wind turbine or to waves. The wave energy is mainly concentrated in the first few meters of sea below the free surface. Support structures floating mainly located near the free surface such as barges or semi-submersible platforms are highly subject to waves, so these structures are generally affected by dynamic stability problems.
    Subject and summary of the invention
    The main object of the present invention is therefore to propose a floating support structure for offshore wind turbines which does not have the aforementioned drawbacks.
    According to the invention, this object is achieved thanks to a floating support structure for offshore wind turbines, comprising a float intended to be partly submerged and on which is intended to be assembled a wind turbine mast, and a counterweight connected to the float. and intended to be immersed under the float, the float comprising:
    a main structure of toroidal or polygonal shape with at least five sides which is formed by at least one tube intended to be submerged;
    a central tubular structure having a diameter adapted to receive the mast of the wind turbine and comprising a section capable of being ballasted in order to adjust the waterline of the float;
    a first series of horizontal struts regularly distributed around a vertical axis and connecting the main structure to the central structure; and a second series of oblique bracons regularly distributed around a vertical axis and connecting the main structure to the central structure by forming an angle between 15 ° and 60 ° with the horizontal bracons.
    The invention thus consists of two elements (the float and the counterweight) which are connected together by ballast links: the floating element is easy to transport, its draft during the construction and installation phase is low, and it is compact and installable by conventional offshore industry solutions, the wind turbine mast and the nacelle can be installed during the construction of the float.
    The floating support structure according to the invention is remarkable in particular by the minimum structure of the float which has a shape of a bicycle wheel carried horizontally in which the buoyancy which is exerted on it would be provided in part by the central tubular structure (corresponding to the wheel hub) and in part by the toric or polygonal structure (corresponding to the tire of the wheel).
    Furthermore, the particular shape of the main structure of the float makes it possible to obtain a thrust which is distributed continuously around the vertical axis, and not a punctual thrust. Likewise, this continuity of shape makes it possible to prevent the forces of the swell on the float from varying with the variations in incidence, unlike a float which would be of punctual distribution.
    In addition, such a structure makes it possible to use a depth of immersion of the float which is typically between 15 and 30 m. At such a depth, due to the continuity of shape of the main structure of the float, the floating support structure is almost transparent to the effects of swell and surface currents, which allows the wind turbine to overcome the maximum dynamic stability problems. More generally, the wind turbine using such a floating support structure could be installed in economically accessible areas because a minimum of water depth of the order of 70m will suffice.
    In this way, the floating support structure according to the invention allows the exploitation of wind energy for the purpose of producing electricity by water depths greater than 70 m, without a high limit of water depth. The wind turbine using such a floating support structure could therefore be located in economically accessible areas.
    The floating support structure according to the invention makes it possible to obtain increased stability in rotation at the level of the wind turbine, both in movement and in acceleration. The mass of materials for the manufacture of this support structure is relatively low, which reduces the manufacturing costs. This floating support structure is also compatible with all current designs of floating wind turbines, with a nominal power of up to 9.5 MW. The structure remains compatible with future wind turbines with a power of 10 to 15 MW and more which should enter into production in the coming years.
    The structure according to the invention provides great stability to the wind turbine supported both in the amplitude in rotational movements and in angular accelerations. This stability relative to the swell, wind and current conditions encountered in the various regions of the world remains compatible with the technical specifications of wind turbines in the offshore wind industry.
    The structure according to the invention requires minimized tension levels in the anchor lines retaining the wind turbine. In addition, it is compatible with industry standard export electrical cable designs. It minimizes the surface area of the free surface, does not physically interfere with the navigation of small vessels in the immediate vicinity, and minimizes the mass of structural materials used by the floating support structures of wind turbines.
    The manufacture of the structure according to the invention can be carried out in the various structural materials. It preferably uses metallic materials and manufacturing methods that are standard in the offshore structure construction industry. The structure according to the invention can also use non-metallic materials at the level of the tendons and of the anchoring system which are in the range of current standard capacities in the industry.
    Furthermore, the dimensions, weight and draft of the floating support structure are compatible with most industrial ports and allow the assembly of the elements of the wind turbine on the support structure moored alongside the quay. The assembly of the support structure and the wind turbine can be towed by flotation by sea conditions compatible with most regions of the globe. These operations can be carried out in complete safety with acceptable operational risk conditions using conventional means of installation in the industry. Alternatively, the assembly of the floating support structure and the wind turbine can be done at sea.
    Preferably, the counterweight comprises a basket capable of receiving ballast material and ballast links connecting the basket to the main structure of the float at an angle between 15 ° and 45 ° with the vertical axis.
    In order to have a floating support structure stable by weight and not by shape, the point of action of Archimedes' thrust should be located above its center of gravity. The center of gravity of a wind turbine being located quite high at mast level, due to the weight of the nacelle and the blades, it is advisable to add a counterweight at the bottom of the support structure. This counterweight will apply a resistant torque to the level of the support structure.
    In this case, the ballast links form an angle β with the vertical axis given by the following equation: β = arctan [(Dc / 2 + Lh + Df) / (P - Te - Ep - Gp)]; where: P is the water depth; Te is the draft measured at the bottom of the main structure; Ep is the thickness of the basket; Gp is the distance between the bottom of the basket and the seabed; De is the diameter of the central tubular structure; Lh is the length of the horizontal posts; and Df is the diameter of the tubes of the main structure.
    Preferably, the counterweight comprises a plurality of baskets each capable of receiving a ballast material and positioned vertically one below the other, being regularly spaced.
    Also preferably, the oblique bracons form an angle of 30 ° with the horizontal bracons.
    More preferably, the float further comprises an additional buoyancy structure formed by an assembly of additional floats mounted on the tube of the main structure.
    Still preferably, when the main structure of the float is formed by an assembly of a plurality of tubes, these are connected together by means of joint plates welded to the ends of the tubes.
    The invention also relates to a first embodiment of a method for installing an offshore wind turbine provided with a floating support structure as defined above, comprising the steps of:
    transport at sea of an empty basket of the counterweight of the floating support structure;
    lowering into the sea of the empty basket of the counterweight on which temporary flotation modules have been previously fixed and mooring of it to a dead body previously deposited on the sea bottom;
    activation of the temporary flotation modules of the basket to allow it to stabilize between two waters above the dead body;
    towing of the float of the support structure floating at sea to the vertical of the empty basket of the counterweight;
    connection of the main structure of the float to the empty basket of the counterweight by means of ballast links;
    ballasting the empty basket of the counterweight to allow it to be disconnected from the dead body;
    filling the counterweight basket with ballast material to partially immerse the float; and towing at sea of the float connected to the counterweight to the installation area of the wind turbine.
    According to a second embodiment of a method for installing an offshore wind turbine provided with a floating support structure as defined above, the method comprises the successive steps of:
    transport at sea and deposit on the seabed an empty basket of the counterweight of the floating support structure;
    filling the counterweight basket placed on the seabed with ballast material;
    towing at sea of the float of the support structure floating up to the vertical of the basket filled with the counterweight;
    connection at low tide of the main structure of the float to the basket filled with the counterweight by means of ballast links;
    tensioning of the ballast links and release of the counterweight basket by effect of the rising tide; and towing at sea of the float connected to the counterweight to the installation area of the wind turbine.
    In this second embodiment, preferably temporary buoys can be connected to the counterweight basket to reduce the weight when the seabed is lifted off.
    In a variant, the basket of the counterweight can be deposited on the seabed by means of a raising system on which the basket rests.
    According to a third embodiment of a method for installing an offshore wind turbine provided with a support structure as defined above, the method comprises the successive steps of:
    transport at sea separately from an empty and floating basket of the counterweight of the floating support structure and its float;
    connection of ballast links and ballast chains between the basket and the float;
    immersion of the basket by its progressive ballasting and control of its position by the catenary effect of the ballast chains to lower it into a position of equilibrium under the float;
    lowering the basket under the float until the ballast links are tight;
    filling the counterweight basket with ballast material to partially immerse the float; and towing at sea of the float connected to the counterweight to the offshore installation area of the wind turbine.
    According to a fourth embodiment of a method for installing an offshore wind turbine provided with a floating support structure as defined above, the method comprises the successive steps of:
    joint transport of a basket of counterweight positioned under the floating support structure and its float;
    vertical descent of the basket by means of a lifting system preferably integrated at the level of the float;
    towing at sea of the float connected to the counterweight to the installation area of the wind turbine; and filling the counterweight basket suspended from the float structure with ballast material.
    According to a fifth embodiment of a method for installing an offshore wind turbine provided with a floating support structure as defined above, the method comprises the successive stages of:
    connection of ballast links and ballast chains between the counterweight basket and the float;
    joint towing at sea of the float connected to the counterweight positioned under the floating support structure up to the installation area of the wind turbine;
    immersion of the basket by progressive ballasting of the basket and control of the basket position by the catenary effect of the ballast chains to lower it into an equilibrium position under the float;
    lowering the basket under the float until the ballast links are tight;
    filling the counterweight basket with ballast material to immerse the float.
    Brief description of the drawings
    Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the accompanying drawings which illustrate exemplary embodiments thereof without any limiting character. In the figures:
    - Figure 1 is a side view of an offshore wind turbine mounted on a floating support structure according to the invention;
    - Figure 2 is a perspective view of the float of the floating support structure of Figure 1;
    - Figure 3 is a perspective view and cutaway of a basket of the floating support structure of Figure 1;
    - Figure 4 is a top view of the basket of Figure 4;
    - Figure 5 is a sectional view along V-V of Figure 4;
    - Figures 6A to 6Q illustrate the different steps of a method of installing an offshore wind turbine provided with a floating support structure according to a first embodiment of the invention;
    - Figures 7A to 7K illustrate the different steps of a method of installing an offshore wind turbine provided with a floating support structure according to a second embodiment of the invention; and
    - Figures 8A to 8H illustrate the different steps of a method of installing an offshore wind turbine provided with a floating support structure according to a third embodiment of the invention;
    - Figures 9A to 10C illustrate the different stages of a method of installing an offshore wind turbine provided with a floating support structure according to a fourth embodiment of the invention; and
    - Figures 10A to 10D illustrate the different stages of a method of installing an offshore wind turbine provided with a floating support structure according to a fifth embodiment of the invention.
    Detailed description of the invention
    Figure 1 shows, in side view, a floating offshore wind turbine 2 located at sea off the coast.
    In known manner, such a wind turbine 2 comprises a turbine 4 generally formed by a motor with several rotary blades with a substantially horizontal axis XX, and an electric generator 6 coupled to the motor, the motor and the generator being fixed at an upper end of a vertical mast 8 (or pylon). The lower end of the mast 8 is itself mounted on a floating support structure 10 according to the invention.
    According to the invention, the floating support structure 10 consists of a float 12 which is intended to be partly submerged (the sea level is symbolized in FIG. 1 by the line 14) and a counterweight 16 which is connected to the float 12 and which is intended to be immersed under it. The lower end of the mast 8 of the wind turbine is assembled on the float 12 of the floating support structure.
    As shown in Figure 2, the float 12 comprises a main structure 18 a polygonal shape with at least five sides, this main structure of polygonal shape being formed by an assembly of tubes 20 of circular section intended to be immersed. Alternatively, the main structure has a toroidal shape. In this variant, it is formed by a single tube with circular section.
    In the example illustrated in these figures, the main structure 18 of the float has a polygonal shape with six sides. Such a hexagonal shape represents the preferred embodiment. Indeed, this form offers the best compromise in terms of structure and hydrodynamic behavior.
    The tubes 20 of the main structure of the float are of circular section and are connected to each other by means of junction plates 22 which are welded to the ends of the tubes. These tubes 20 are stiffened by a system of crossed stiffeners (not shown in the figures) making it possible to optimize the weight of the structure subjected to hydrostatic pressure. The tubes are compartmentalized so that the stability of the system is not called into question if one of these compartments becomes filled with seawater.
    Furthermore, the main structure 18 of the float further comprises an additional buoyancy structure formed by an assembly of additional floats 24 which are mounted on the tubes 20 and which make it possible to raise the freeboard of the float and wind assembly in towing phases to improve stability. These additional floats can be collected after the towing phase or left on the float after immersion.
    The float 12 also comprises a central tubular structure 26 centered on a vertical axis Y-Y and having a diameter adapted to receive the mast 8 of the wind turbine. This central structure 26 comprises a section (not shown in the figures) which is capable of being ballasted with sea water in order to adjust the waterline of the float to the desired immersion depth.
    The float 12 also comprises a first series of horizontal struts 28 which are regularly distributed around the vertical axis YY and which connect each end of the tubes 20 of the main structure to the central structure 26, and more particularly to the lower part of that -this. There are as many horizontal struts 28 as there are tubes 20 forming the main structure.
    This structure of horizontal struts 28, of the reticulated type although very simple, makes it possible to reduce the bending moments in the tubes 20 of the main structure at secondary moments. This makes it possible to optimize the working mode of the tubes in traction and compression.
    The float 12 also comprises a second series of oblique bracons 30 which are also regularly distributed around the vertical axis YY and which connect each end of the tubes 20 of the main structure to the central structure, and more particularly to the upper part of that here, by forming an angle a between 15 ° and 60 ° - and preferably equal to 30 ° - with the horizontal bracons 28. As for the horizontal bracons, there are as many oblique bracons 30 as there are tubes 20 forming the structure main.
    The horizontal 28 and oblique 30 bracons are in the form of tubes. The connection between the struts and the main structure of the float is made at the level of the junction plates 22. This assembly technique makes it possible to facilitate the adjustment and the welding of the large struts.
    Furthermore, as shown in FIGS. 3 to 5, the counterweight 16 of the floating support structure according to the invention comprises a basket 32 which is capable of receiving a ballast material 34.
    In order to provide a large mass counterweight while reducing costs, a heavy material that is both economical and compatible with the marine environment should be used. In a preferred embodiment, the best compromise for ballast material 34 is found with heavy ballast materials. Typically, this ballasting material can be magnetite chemically stabilized in order to be made compatible with the environment. Alternatively, this ballast material can be embankment material, sand, cast iron shot or reclaimed metal.
    In order to be able to support this ballasting material 34, it should be placed in a basket 32 designed to support the efforts. The diameter of the basket varies, depending on the application, typically between 8m and 22m and its height between 6m and 10m.
    The basket 32 of the counterweight consists of a cylindrical envelope 32a terminated by a domed or frustoconical bottom 32b in its lower part. The weight is taken up by ballast links 36 (or tendons) - preferably six in number - connecting the basket at each end of the tubes 20 of the main structure.
    More specifically, these ballast links 36 come together on a central cylindrical connector 38 which is located in the center of the cylindrical envelope 32a of the basket in its upper part.
    The central connector 38 makes it possible to concentrate the weight of the counterweight at a central point situated in the axis of the central structure 26 of the float. This concentration of weight at one point is a key factor in the effectiveness of the counterweight system, it allows the ballast to remain stationary relative to the float regardless of the angle of inclination as long as the ballast links 36 remain all taut .
    As shown in Figure 1, the ballast links 36 connecting the basket 32 at each end of the tubes 20 of the main structure form an angle β between 15 ° and 45 ° with the vertical axis Y-Y.
    The angle β formed by the ballast links 36 with the vertical axis is preferably given by the following equation:
    β = arctan [(Dc / 2 + Lh + Df) / (P - Te - Ep - Gp)] in which: P is the water depth; Te is the draft measured at the bottom of the main structure; Ep is the thickness of the basket; Gp is the distance between the bottom of the basket and the seabed; De is the diameter of the central structure; Lh is the length of the horizontal posts; and Df is the diameter of the tubes of the main structure.
    The bottom of the float 12 of the floating support structure according to the invention is located at a typically immersion depth of 25 m. The minimum structure for taking up tensile forces are the ballast links 36. The counterweight is therefore attached to the float by as many ballast links as the main structure of the float has sides. At this level, the ballast links 36 are connected to the junction plates 22.
    The ballast links 36 can be as light as possible because their mass plays only a marginal role in the stability of the floating support structure. They must also be able to take up the forces generated by the weight of the counterweight and have a minimum elasticity and deformation over time.
    Also, in a preferred embodiment, these ballast links are ropes made of synthetic materials having a low elongation (typically high density polyethylene). These materials combine good mechanical properties with a negative weight in water (material density less than 1). Alternatively, these ballast links can be cables, chains or metal tubes.
    The spacing of the attachment points of the ballast links 36 on the main structure 18 of the float is chosen so that when the inclination of the direction of the mast 8 of the wind turbine with the vertical axis YY is maximum, all ballast links remain in tension. The forces to which the system is subjected are increased by a safety factor depending on the application case. In this way, the inclination of the wind turbine under the action of the resulting drag of the wind force and the weight of the wind turbine causes a transfer of tension from the ballast links located in the opposite direction to the wind towards those located in the direction of the wind. The counterweight then remains in the axis of the wind turbine mast and this flexible structure behaves mechanically like a rigid structure, the ballast remaining fixed relative to the float. In other words, this pendular structure achieves the counterweight function of a "spar" platform, while having a lighter structure, transparent to swell and installable with the wind turbine attached to the float in port.
    The floating support structure according to the invention is designed so as to be stable without an anchoring system. The anchoring system therefore does not participate in the stability of the floating support structure. This creates much lower levels of tension in the anchor lines and geotechnical constraints on the weakened anchors.
    In connection with FIGS. 6A to 6Q, there will be described a method of installation according to a first embodiment of the invention of an offshore wind turbine provided with a floating support structure as described above.
    FIGS. 6A to 6H illustrate the various stages of preparation and installation at the bottom of the sea of the counterweight of the floating support structure according to the invention.
    In FIG. 6A, a barge 100 transporting in particular the basket 32 of the counterweight of the floating support structure and a dead body 104 is brought to sea on site. The dead body 104 is then lowered to sea vertically from the barge 100 by a crane 106 (FIG. 6B) and then deposited on the seabed (FIG. 6C).
    An unmanned underwater vehicle 108 (also called ROV for “Remotely Operated Vehicle”) to supervise these operations and then to install a rope 110 on the dead body 104 as shown in FIG. 6D. Here, the rope 110 is a rope connected to a temporary buoy on the one hand and to a dead body 104 on the other hand, in order to provide a point of attachment to the dead body above the sea bottom and in below the final depth of the ballast basket.
    During the next step represented by FIG. 6E, the basket 32 (empty) of the counterweight of the floating support structure is also lowered by the crane 106 from the barge to the bottom of the sea to be connected to the boat. 110 under the control of ROV 108 (Figure 6F). Flotation modules 112 (three in number in the figures) previously filled with air are then lowered into the sea from the barge and fixed on the basket 32 of the counterweight (Figure 6G). At the end of this stage, this coupling is disconnected from the barge 100 and the ROV 108 is re-installed on board the latter (FIG. 6H).
    As illustrated in FIGS. 61 and 6J, the float 12 of the floating support structure on which the mast 8 of a wind turbine 2 has previously been mounted is then towed by a tug 114 vertical to the basket 32 of the counterweight moored to the body dead 104. This towing can be carried out by means of a tug connected to the main structure 18 of the float by one or more towing cables 116.
    When the float 12 and the wind turbine 2 are vertical to the basket 32 of the counterweight, the ROV 108 is again deployed to connect the main structure of the float to the basket by means of the ballast links 36 (FIG. 6J). In order to stabilize the position of the float 12 above the counterweight basket, it may be necessary to use several tugs regularly spaced around it.
    During the next step represented by FIG. 6K, the air present inside the flotation modules 112 is then released (and replaced by sea water). The ROV 108 can then be controlled to detach one after the other each flotation module emptied of its air to reassemble it in the barge 100 by means of a rope 118 of the crane 106 (FIG. 6L).
    Once the flotation modules have been removed, the basket 32 of the counterweight acts on the ballast links 36 to tension them and the rope 110 is meanwhile relaxed (FIG. 6M). The orin 110 can thus be easily disconnected from the counterweight basket by the ROV 108 (Figure 6N). The float 12 and the wind turbine with the basket 32 of the counterweight connected by the ballast links are then towed by the tug 114 to the installation area of the offshore wind turbine (Figure 60).
    Once the float 12 and the wind turbine 2 positioned and kept vertical to its chosen implantation area, a barge 120 fills the basket 32 of the counterweight with the ballasting material 34. This operation can be carried out using a tube 122 connecting the basket to the barge 120 (FIG. 6P).
    As shown in FIG. 6Q, the filling of the basket 32 of the counterweight with the ballasting material 34 has the consequence of causing the float 12 to be immersed, this immersion being controlled to allow the bottom of the float 12 of the floating support structure to be located at its immersion depth (typically 25 m).
    It will be noted that the counterweight can comprise a plurality of baskets each receiving a ballast material and which are positioned vertically one below the other, being regularly spaced (for example every 10 m).
    In connection with FIGS. 7A to 7K, there will now be described an installation method according to a second embodiment of the invention of an offshore wind turbine provided with a floating support structure as described above.
    During a first step (FIG. 7A), a barge 200 prepares the temporary area of the seabed in order to allow it to support the weight of the baskets filled with ballast of the counterweights of several floating support structures. This preparation consists in dumping on the seabed an embankment material allowing the seabed to be able to support the weight of the baskets loaded with ballast material while keeping an acceptable attitude stability.
    Once the seabed is prepared, a set of baskets 32 empty of counterweights are lowered into the sea from barge 200 and deposited on the seabed using a crane 202 (FIG. 7B). The counterweight baskets are deposited one after the other when the barge advances, their number depending on the number of offshore wind turbines in the field to be installed (Figure 7C).
    As shown in FIG. 7D, the counterweight baskets 32 deposited on the seabed are then filled one after the other with a ballast material 34 from the barge. Once the baskets are filled with ballast material, temporary buoys 204 are connected to these baskets by means of the crane 202 of the barge and by means of a ROV 206 (FIG. 7E). FIG. 7F shows the set of counterweight baskets each provided with several temporary buoys 204.
    During the next step represented by FIG. 7G, the float 12 of the floating support structure on which the mast 8 of a wind turbine has been previously mounted is then towed by a tug 208 above a basket 32 counterweight. At low tide, the main structure of the float is then connected to the counterweight basket by means of ballast links 36 (Figure 7G).
    By effect of the rising tide, the basket 32 of the counterweight lifts from the seabed thanks to the ballast links 36 (FIG. 7H) in order to allow towing of the float 12 and of the basket by the tug 208 to the implantation area. offshore wind turbines (Figure 71).
    Once the float 12 and the counterweight basket positioned and kept vertical to the chosen implantation area, the barge 200 is brought to disconnect one after the other the temporary buoys 204 from the basket 32. This operation is carried out by ROV 206 which disconnects each temporary buoy and reassembles it on board the barge using a rope 210 (Figure 7J).
    When all the temporary buoys are disconnected, the “ballastable” section of the central structure 26 of the float 12 is filled with sea water in order to adjust the waterline of the float to the desired immersion depth (FIG. 7K).
    In a variant of this second embodiment (not shown in the figures), provision is made, in place of the step of preparing the temporary area of the seabed to allow it to support the weight of the baskets filled with ballast of the counterweight, to deposit on the seabed a system for lowering the counterweight.
    In this variant, the raising system can thus totally or partially replace the effect of the rising tide on the relative position of the basket relative to the bottom. Depending on the case, the basket can be filled with ballast material entirely or partially on the basket placed on the riser system. In the case where the filling is done partially on the basket placed on the raising system, additional ballast material is made once the basket is detached from the raising system.
    This counterweight lowering system comprises a wide base allowing the seabed to support the weight of the system and the empty basket of the counterweight of the floating support structure according to the invention. Once the empty basket is lowered and placed on the base, the steps of the installation process similar to those described above in conjunction with Figures 7D to 7K.
    This alternative embodiment may be preferred because it has the advantage of being free from the tide.
    In connection with FIGS. 8A to 8H, a third embodiment of the installation method according to the invention of an offshore wind turbine with a floating support structure as described above will be described.
    This variant is particularly advantageous for the dynamic behavior of the counterweight during the descent by linking the basket thereof to the float by means of several catenary chains, which makes it possible to decouple the movements of the one and the other. In addition, no preparation of the seabed is required.
    According to a first step illustrated in FIG. 8A, a first tug 300 is used to tow at sea the float 12 of the floating support structure on which the mast of a wind turbine 2 has been previously mounted. The basket 32 empty of the counterweight of the floating support structure is in turn towed independently by a second tug 302.
    Note that to facilitate the towing of the counterweight basket, it can be provided with temporary buoys 304. It will also be noted that the two tugs 300, 302 are each equipped with a dynamic positioning system.
    Once arrived at the installation area at sea of the wind turbine, the tugs 300, 302 maneuver to bring the float 12 closer to the basket 32 in order to allow the establishment of the connections between these two elements (FIG. 8B).
    These connections are in particular the ballast links 36 connecting the basket 32 at each end of the tubes of the main structure of the float. This operation can be carried out using a dynamic positioning connection boat 306.
    As shown in FIG. 8C, ballast chains 308 are also connected between different points of the basket 32 and the main structure of the float 12. These ballast chains are for example three in number. During these operations, other retaining links (not shown in the figures) can be connected between the basket and the float to limit the distance of the float from the basket.
    During the next step, the basket 32 of the counterweight is moved away from the float 12 and then gradually immersed by reducing the buoyancy of the temporary buoys 304 or by adding weight to the basket (FIG. 8E). The immersion of the basket is continued until a first position of equilibrium under the float (Figure 8F).
    The basket 32 of the counterweight is lowered further by continuously reducing or by compensating for the buoyancy of the temporary buoys (or by adding ballast). It will be noted that the descent of the basket results in a reduction in the catenary of the ballast chains 308 under the basket and therefore in the weight which must be compensated by flotation. It is envisaged a process in which the descent of the basket would automatically cause the drop in its buoyancy and also a drop in the ballast with an offset such that the speed of descent of the basket would be sufficiently low.
    The descent of the basket ends when the ballast links 36 are tensioned (Figure 8G). If necessary, it can be envisaged that the descent will stop automatically at desired depths (for example slightly before the ballast links are stretched to be able to ensure that their configuration is acceptable) while ensuring that the loss of ballast is caught up by the loss of flotation at the desired depth.
    Finally, the basket 32 of the counterweight is filled with the ballast material 34, for example from a ballast boat 310 pouring the ballast material into the basket using a gutter or filling tube 312 (FIG. 8H).
    This last stage can be replaced by the filling of flotation elements linked to the basket in the case where the ballast was already present in this particular basket having a buoyancy reserve equivalent to the final weight seen by the ballast links.
    It will be noted that the ballast chains 308 could be used to serve to make, if necessary, an anchoring system for the floating support structure.
    In connection with FIGS. 9A to 9C, a fourth embodiment of the installation method according to the invention of an offshore wind turbine provided with a floating support structure as described above will be described.
    In this fourth embodiment, it is planned to transport at sea jointly by a tug 400 the float 12 with its basket 32 of counterweight empty of ballast positioned below the floating support structure up to the installation area of the wind turbine (Figure 9A).
    The basket 32 is then lowered by a lifting system 402 installed at the level of the platform of the wind turbine 2 until the ballast links are tensioned (FIG. 9B). The float 12 connected to the counterweight is then towed to the installation area of the wind turbine and the basket 32 can then be filled with ballast material from a ballast boat 404 as described above (this is ie by means of a tube 406 connecting the basket to the ballast boat - see Figure 9C).
    In connection with FIGS. 10A to 10D, there will now be described a fifth embodiment of the installation method according to the invention of an offshore wind turbine provided with a floating support structure as defined above.
    In this fifth embodiment, the method comprises in a first step illustrated in FIG. 10A, the connection of ballast links 36 and ballast chains 500 between the basket 32 of the counterweight and the float 12. Once this operation has been carried out, the float connected to the counterweight is towed at sea using a tug 502 to the installation area of the wind turbine (Figure 10B). At the same time, the empty basket 32 of the counterweight positioned under the floating support structure and of its float is transported to sea.
    The basket is progressively submerged by ballasting and the position of the basket is controlled by the catenary effect of the ballast chains to lower it into an equilibrium position under the float (Figure 10C).
    The basket 32 is then lowered under the float until the ballast links 36 are tensioned, then it is filled with a ballast material in order to immerse the float (FIG. 10D). Finally, the float connected to the counterweight is towed to the installation area of the wind turbine.
    权利要求:
    Claims (14)
    [1" id="c-fr-0001]
    1. Floating support structure (10) for offshore wind turbines (2), comprising a float (12) intended to be partially submerged and on which is intended to be assembled a wind turbine mast (8), and a counterweight (16 ) connected to the float and intended to be submerged under the float, characterized in that the float (12) comprises:
    a main structure (18) of toroidal or polygonal shape with at least five sides which is formed by at least one tube (20) intended to be submerged;
    a central tubular structure (26) having a diameter adapted to receive the mast (8) of the wind turbine and comprising a section capable of being ballasted in order to adjust the waterline of the float;
    a first series of horizontal struts (28) regularly distributed around a vertical axis and connecting the main structure to the central structure; and a second series of oblique bracons (30) regularly distributed around a vertical axis (YY) and connecting the main structure to the central structure by forming an angle (a) between 15 ° and 60 ° with the horizontal bracons (28 ).
    [2" id="c-fr-0002]
    2. Structure according to claim 1, wherein the counterweight (16) comprises a basket (32) capable of receiving a ballast material (34) and ballast links (36) connecting the basket to the main structure (18) of the float by forming an angle (β) between 15 ° and 45 ° with the vertical axis (YY).
    [3" id="c-fr-0003]
    3. Structure according to claim 2, in which the ballast links (36) form an angle (β) with the vertical axis (Y-Y) given by the following equation:
    β = arctan [(Dc / 2 + Lh + Df) / (P - Te - Ep - Gp)] in which: P is the water depth; Te is the draft measured at the bottom of the main structure; Ep is the thickness of the basket; Gp is the distance between the bottom of the basket and the seabed; De is the diameter of the central structure; Lh is the length of the horizontal posts; and Df is the diameter of the tubes of the main structure.
    [4" id="c-fr-0004]
    4. Structure according to one of claims 2 and 3, wherein the counterweight comprises a plurality of baskets each capable of receiving a ballast material and positioned vertically one below the other being regularly spaced.
    [5" id="c-fr-0005]
    5. Structure according to any one of claims 1 to 4, in which the oblique bracons (30) form an angle (a) of 30 ° with the horizontal bracons (28).
    [6" id="c-fr-0006]
    6. Structure according to any one of claims 1 to 5, in which the float further comprises an additional buoyancy structure formed by an assembly of additional floats (24) mounted on the tube (20) of the main structure (18) .
    [7" id="c-fr-0007]
    7. Structure according to any one of claims 1 to 6, in which the main structure (18) of the float is formed by an assembly of a plurality of tubes (20) which are connected together by means of plates of junction (22) welded to the ends of the tubes.
    [8" id="c-fr-0008]
    8. A method of installing an offshore wind turbine at sea provided with a floating support structure according to any one of claims 1 to 7, comprising the successive steps of:
    transport at sea and deposit on the seabed of a basket (32) empty of the counterweight (16) of the floating support structure;
    filling the counterweight basket placed on the seabed with ballast material (34);
    towing at sea of the float (12) of the support structure floating up to the vertical of the basket filled with the counterweight;
    connection at low tide of the main structure (18) of the float to the basket filled with the counterweight by means of ballast links (36);
    tensioning of the ballast links and release of the counterweight basket by effect of the rising tide; and towing at sea of the float connected to the counterweight to the installation area of the wind turbine.
    [9" id="c-fr-0009]
    9. The method of claim 8, wherein the buoys (204) are connected to the basket of the counterweight to reduce the weight when the detachment from the seabed.
    [10" id="c-fr-0010]
    10. The method of claim 8, wherein the counterweight basket is deposited on the seabed by means of a raising system on which the basket rests.
    [11" id="c-fr-0011]
    11. A method of installing an offshore wind turbine provided with a floating support structure according to any one of claims 1 to 7, comprising the successive steps of:
    transport at sea separately from an empty and floating basket (32) of the counterweight (16) of the floating support structure and its float (12);
    connection of ballast links (36) and ballast chains (308) between the basket and the float;
    immersion of the basket by its progressive ballasting and control of its position by the catenary effect of the ballast chains to lower it into a position of equilibrium under the float;
    lowering the basket under the float until the ballast links (36) are tensioned;
    filling the counterweight basket with ballast material (34) to partially immerse the float; and towing at sea of the float connected to the counterweight to the offshore installation area of the wind turbine.
    [12" id="c-fr-0012]
    12. A method of installing an offshore wind turbine fitted with a floating support structure according to any one of claims 1 to 7, comprising the steps of:
    transport at sea of an empty basket (32) of the counterweight (16) of the floating support structure;
    lowering into the sea of the empty basket of the counterweight on which temporary flotation modules (112) have been previously fixed and mooring it to a dead body (114) previously deposited at the bottom of the sea;
    activation of the temporary flotation modules of the basket to allow it to stabilize between two waters above the dead body;
    towing the float (12) at sea of the floating support structure to the vertical of the empty basket of the counterweight;
    connection of the main structure (18) of the float to the empty basket of the counterweight by means of ballast links (36);
    ballasting the empty counterweight basket to allow it to be disconnected from the dead body (104);
    filling the counterweight basket with ballast material (34) to partially immerse the float; and towing at sea of the float connected to the counterweight to the installation area of the wind turbine.
    [13" id="c-fr-0013]
    13. A method of installing an offshore wind turbine provided with a floating support structure according to any one of claims 1 to 7, comprising the successive steps of:
    joint transport of a basket (32) of the counterweight (16) positioned under the floating support structure and its float (12);
    vertical descent of the basket by means of a lifting system (402) integrated at the level of the float;
    towing at sea of the float connected to the counterweight to the installation area of the wind turbine; and filling the counterweight basket suspended from the float structure with ballast material.
    [14" id="c-fr-0014]
    14. A method of installing an offshore wind turbine provided with a floating support structure according to any one of claims 1 to 7, comprising the successive steps of:
    connection of ballast links (36) and ballast chains (308) between the basket (32) of the counterweight and the float (12);
    joint towing at sea of the float connected to the counterweight positioned under the floating support structure up to the installation area of the wind turbine;
    immersion of the basket by progressive ballasting of the basket and control of the basket position by the catenary effect of the ballast chains to lower it into an equilibrium position under the float;
    lowering the basket under the float until the 5 ballast links (36) are tensioned; and filling the counterweight basket with ballast material (34) to immerse the float.
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    同族专利:
    公开号 | 公开日
    AU2018376719B2|2021-05-06|
    KR20200060766A|2020-06-01|
    EP3717343A1|2020-10-07|
    FR3074138B1|2021-08-27|
    EP3854673A1|2021-07-28|
    AU2018376719A1|2020-05-14|
    EP3854670A1|2021-07-28|
    EP3854671A1|2021-07-28|
    PH12020550612A1|2021-02-22|
    EP3854672A1|2021-07-28|
    EP3854669A1|2021-07-28|
    US20200391834A1|2020-12-17|
    KR102317990B1|2021-10-28|
    WO2019106283A1|2019-06-06|
    BR112020008842A2|2020-10-20|
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    法律状态:
    2018-11-22| PLFP| Fee payment|Year of fee payment: 2 |
    2019-05-31| PLSC| Publication of the preliminary search report|Effective date: 20190531 |
    2019-11-21| PLFP| Fee payment|Year of fee payment: 3 |
    2020-11-23| PLFP| Fee payment|Year of fee payment: 4 |
    2021-11-22| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1761342A|FR3074138B1|2017-11-29|2017-11-29|FLOATING SUPPORT STRUCTURE FOR OFFSHORE WIND TURBINE AND METHOD OF INSTALLING A WIND TURBINE EQUIPPED WITH SUCH A SUPPORT STRUCTURE|
    FR1761342|2017-11-29|FR1761342A| FR3074138B1|2017-11-29|2017-11-29|FLOATING SUPPORT STRUCTURE FOR OFFSHORE WIND TURBINE AND METHOD OF INSTALLING A WIND TURBINE EQUIPPED WITH SUCH A SUPPORT STRUCTURE|
    EP21162733.6A| EP3854670A1|2017-11-29|2018-11-27|Method for installing an offshore wind turbine provided with a floating support structure|
    EP21162744.3A| EP3854673A1|2017-11-29|2018-11-27|Method for installing an offshore wind turbine provided with a floating support structure|
    AU2018376719A| AU2018376719B2|2017-11-29|2018-11-27|Floating support structure for offshore wind turbine and method for installing a wind turbine provided with such a support structure|
    EP18827192.8A| EP3717343A1|2017-11-29|2018-11-27|Floating support structure for offshore wind turbine and method for installing a wind turbine provided with such a support structure|
    EP21162730.2A| EP3854669A1|2017-11-29|2018-11-27|Method for installing an offshore wind turbine provided with a floating support structure|
    US16/767,474| US20200391834A1|2017-11-29|2018-11-27|Floating support structure for offshore wind turbine and method for installing a wind turbine provided with such a support structure|
    PCT/FR2018/053006| WO2019106283A1|2017-11-29|2018-11-27|Floating support structure for offshore wind turbine and method for installing a wind turbine provided with such a support structure|
    EP21162736.9A| EP3854671A1|2017-11-29|2018-11-27|Method for installing an offshore wind turbine provided with a floating support structure|
    EP21162740.1A| EP3854672A1|2017-11-29|2018-11-27|Method for installing an offshore wind turbine provided with a floating support structure|
    KR1020207013413A| KR102317990B1|2017-11-29|2018-11-27|Float support structures for offshore wind turbines and methods for installing wind turbines with such support structures|
    BR112020008842-0A| BR112020008842A2|2017-11-29|2018-11-27|floating support structure for offshore wind turbine and method for installing a wind turbine provided with such support structure|
    PH12020550612A| PH12020550612A1|2017-11-29|2020-05-11|Floating support structure for offshore wind turbine and method for installing a wind turbine provided with such a support structure|
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