FR3093699A1 - Semi-submersible wind turbine float, associated wind turbine assembly and anchoring method - Google Patents

Abstract

Title: Semi-submersible wind turbine float, wind turbine assembly and associated anchoring method The invention relates to a wind turbine float (14) comprising: a central column (24), at least two stabilization columns (26 ), at least two pontoons (20) and at least one anchor line (21) associated with one of the stabilization columns and defining a distal end (42) intended to be attached to the seabed (56). The float further comprises deployment means (22) of each anchor line comprising: - for each anchor line, at least one fixing member (46) intended to releasably fix the distal end in such a way that a portion of this anchoring line extends between the central column and the corresponding stabilization column before the mooring of the float; - a winch (48) suitable for adjusting the length of this portion of the anchor line. Figure for abstract: Figure 1

Description

Semi-submersible wind turbine float, associated wind turbine assembly and anchoring method

The present invention relates to a semi-submersible wind turbine float.

The present invention also relates to a wind turbine assembly comprising such a float and a wind turbine supported by the float.

The present invention also relates to a method for towing such a wind turbine assembly.

Floats are already known in the prior art, such as for example from document WO 2014/031009. This document describes a float which comprises at least four columns, for example made of steel, including a central column, and three external stabilization columns, connected to the central column by branches in the form of a concrete and/or steel pontoon.

In order to generate electricity, it is necessary to tow the wind turbine assembly from the port where the assembly was manufactured and/or finalized to an offshore operating site where the wind turbine assembly is anchored on the sea floor.

Anchoring is achieved by means of anchor lines fixed to the stabilization columns.

Known methods of towing and anchoring require the presence of operators and motorized devices at the exterior columns in order to manipulate the anchor lines.

However, some wind turbine floats do not have enough space and access to motorized devices and operators, these known methods are not applicable to these wind turbine floats.

The present invention aims to provide a semi-submersible wind turbine float allowing easy towing and anchoring on the operating site, without the presence of motorized devices and operators on the stabilization columns.

To this end, the subject of the invention is a semi-submersible wind turbine float able to float on a surface of a body of water and defining a lower part intended to be submerged and an upper part intended to be emerged, the float comprising: a central column extending along a main axis-A and capable of supporting a wind turbine; at least two float stabilization columns, each stabilization column extending along an axis substantially parallel to the main axis-A of the central column; at least two pontoons, each stabilization column being connected to the central column by one of the pontoons and at least one anchor line associated with one of the stabilization columns and defining a proximal end permanently fixed to this column stabilizer and a distal end intended to be attached directly or indirectly to the seabed when the float is moored; the float further comprising means for deploying the or each anchor line comprising: for the or each anchor line, at least one fixing member intended to releasably fix the distal end of this line of anchoring in such a way that a portion of this anchoring line extends between the central column and the corresponding stabilization column before the float is moored and a winch capable of adjusting the length of this portion of the anchoring line .

According to particular embodiments, the semi-submersible float comprises one or more of the following characteristics, taken separately or in any technically possible combination:

- the deployment means comprise at least three anchor lines, in particular five anchor lines, each stabilization column receiving at least one of the anchor lines;

- the or each fixing member is arranged in the upper part of the float;

- the deployment means comprise, for each anchor line, at least one guide member of the anchor line arranged on the corresponding stabilization column or on the pontoon associated with said stabilization column;

- the deployment means comprise, for each anchor line, at least two guide members including a first guide member arranged on the corresponding stabilization column and a second guide member arranged on the pontoon associated with said stabilization column; and

- the means of deployment comprise, for each anchor line, a buoy fixed at the level of the distal end of the anchor line.

The invention also relates to a wind turbine assembly comprising a float as described above and a wind turbine a wind turbine supported by one of the columns of the float.

The invention also relates to a method for anchoring a wind turbine assembly as described above floating on a body of water, each anchor line extending between the central column and the stabilization column corresponding, the method comprising, for each anchor line, at least the following steps:

- connection of the winch with the associated anchor line;

- increase in the length of the anchor line portion extending between the central column and the stabilization column by means of the winch;

- disconnection of the anchor line with the winch; and

- anchoring the wind turbine assembly to the seabed using the anchor line.

According to particular embodiments, the anchoring method comprises one or more of the following characteristics, taken separately or in any technically possible combination:

- the anchoring method comprises, between the disconnection step and the anchoring step, for each anchor line, a step for releasing the distal end of the anchor line, the distal end floating on the surface of the body of water using the buoy; and

- the anchoring step comprises, for each anchor line, a sub-step for connecting each anchor line with an anchor cable having one end fixed to the seabed.

• [Fig 1] la figure 1 est une vue schématique en perspective d’un ensemble d’éolienne selon l’invention,
• [Fig 2] la figure 2 est une vue schématique de côté du flotteur semi-submersible de la figure 1, et
• [Fig 3] la figure 3 est une vue schématique de l’ensemble d’éolienne de la figure 1 remorqué par un remorqueur.

Other characteristics and advantages of the invention will appear on reading the following description of embodiments of the invention, given by way of example only with reference to the drawings which are:

• [Fig 1] Figure 1 is a schematic perspective view of a wind turbine assembly according to the invention,
• [Fig 2] Figure 2 is a schematic side view of the semi-submersible float of Figure 1, and
• [Fig 3] Figure 3 is a schematic view of the wind turbine assembly of Figure 1 towed by a tug.

A set of wind turbine 10 is shown in Figure 1.

The wind turbine set 10 includes at least one wind turbine 12 and one float 14 semi-submersible.

Wind turbine 12 comprises at least one mast 16, one turbine 17 and one nacelle 18 at least partially supporting turbine 17.

The float 14 is configured to float on a surface S of a body of water, such as the surface of the sea.

The wind turbine assembly 10 has an operational state and a non-operational state.

In the operational state, the float 14 is located on its operating site at sea and anchored, for example, on the seabed. Furthermore, in the operational state of the float 14, the wind turbine assembly 10 is capable of generating electricity. It is particularly understood that in the operational state of the float 14, the turbine 17 is in operation or not. Furthermore, in the operational state of the float 14, the float 14 has a draft T predefined and adjusted by means of ballasts.

In the non-operational state, the wind turbine assembly 10 is not capable of generating electricity. In this state, the float 14 also has a predefined draft which is less than the predefined draft T of the float 14 in the operational state due to the absence of ballast.

In particular, a non-operational state of the wind turbine assembly 10 corresponds to a towing phase of the wind turbine assembly 10 from a port to the operating site.

The float 14 comprises at least three columns, at least three pontoons 20 connecting the columns together, at least one anchor line 21 and means 22 for deploying the or each anchor line 21.

The columns extend along axes substantially parallel to a main axis A-A' shown in Figure 1.

Each pontoon 20 extends along an axis orthogonal to the main axis A-A'.

The columns include in particular a central column 24 intended to receive the wind turbine 12 and at least two external stabilization columns 26. For each stabilization column 26, one of the pontoons 20 connects said stabilization column 26 to the central column 20.

In the embodiment of Figure 1, the float 12 comprises three stabilization columns 26.

The stabilization columns 26 are arranged in a star around the central column 24 and, for example, regularly distributed angularly around the central column 24. Thus, in this case, the angle between each pair of pontoons 20 is substantially equal to 120 degrees.

According to yet another embodiment, the float 14 comprises two stabilization columns 26. In this case, the central column 24 forms the vertex of an isosceles triangle and the two other vertices are formed, respectively, by a stabilization column 26 .

According to another embodiment, the float 14 comprises four stabilization columns 26 regularly distributed angularly around the central column 24. Thus, the angle between two pontoons 20 is substantially equal to 90 degrees.

The central column 24 advantageously has the shape of a cylinder of circular section and axis A-A'.

Referring to Figure 2, the diameter D1 of the central column 24 is for example equal to 10 m.

Center column 24 includes base 24A and head 24B.

The base 24A is arranged in the extension of each pontoon 20. For example, the base 24A is at least partially made of concrete.

The head 24B of the central column 24 is fixed on the base 24A. The head 24B and the base 24A are coaxial with axis A-A'. The head 24B of the central column 24 is, for example, made of steel.

For example, the central column 24 has a height H1 along the main axis A-A' of between 30 m and 40 m.

Each stabilization column 26 advantageously has the shape of a cylinder of circular section and main axis A-A'. For example, the diameter D2 is between 9 m and 9.5 m.

Each stabilization column 26 also includes a base 26A and a head 26B.

The base 26A is arranged in the extension of the associated pontoon 24. For example, base 26A is at least partially concrete.

The head 26B is fixed on the corresponding base 26A. Head 26B and base 26A are coaxial with main axis A-A'.

Each stabilization column 26 has a height H2 along the main axis A-A' comprised, for example, between 30 m and 40 m.

Each pontoon 20 has for example a parallelepiped shape, delimited by four slabs forming the faces of the parallelepiped. Thus, each pontoon 24 comprises a bottom slab 28, a top slab 30 and two side slabs 32 connecting the bottom slab 28 and the top slab 30.

By way of example, each pontoon 20 extends over a distance E of between 20 m and 30 m, orthogonal to the main axis A-A'.

The height H3 of each pontoon 20 along the main axis A-A' is for example between 8 m and 9 m.

The width of each pontoon 20 along a transverse axis is, for example, substantially equal to the diameter D2 of the associated stabilization column 26.

The float 14 further defines a lower part 34, an upper part 36 and an intermediate part 38.

The lower part 34 is intended to be permanently submerged. The lower part 34 comprises at least part of the base 26A of each stabilization column 26, part of the base 24A of the central column 24 and part of each pontoon 20.

The upper part 36 is intended to be permanently emerged. The upper part 36 comprises at least a part of the head 26B of each stabilization column 26 and a part of the head 24B of the central column 24.

The intermediate part 38 is intended to be submerged or emerged depending on the operational state or not of the wind turbine assembly 10. The intermediate part 38 comprises at least a part of the head 26B of each stabilization column 26 and a part of the head 24B of the central column 24 and optionally at least part of the base 26A of each stabilization column 26, part of the base 24A of the central column 24 and part of each pontoon 20.

The float 14 advantageously comprises at least three anchor lines 21, in particular five anchor lines 21.

Each anchor line 21 is for example a metal cable or a chain.

The length of the anchor line 21 is for example between 20 m and 50 m, in particular between 40 m and 45 m.

Each anchor line 21 defines a proximal end 40 and a distal end 42.

The proximal end 40 is permanently fixed to one of the columns by a fixation device 44.

In particular, the proximal end 40 is attached to one of the stabilization columns 26.

Advantageously, each stabilization column 26 receives at least one of the anchor lines 21.

In an advantageous embodiment, when the float 14 comprises three stabilization columns 26, two stabilization columns 26 are each linked to a respective anchor line 21 and a stabilization column 26 is linked to three anchor lines 21. This arrangement allows the float 14 to be anchored more stable and safer depending on the main direction of the wind.

Each fixing device 44 is capable of allowing two degrees of freedom to the anchoring line 21 at the level of the fixing in order to avoid constraints due to changes in orientation of the anchoring line 21.

Each fixing device 44 is arranged on the stabilization column 26 opposite the pontoon 20.

Each fixing device 44 is advantageously arranged in the lower part 34 of the float 14.

The distal end 42 of each anchor line 21 is intended to be attached directly or indirectly to the seabed 56 when the float 14 is moored.

As visible in Figures 1 and 2, the deployment means 22 comprise at least one fixing member 46 and a winch 48.

Advantageously, the deployment means 22 further comprise, for each anchor line 21, at least one guide member 50 and one buoy 52.

In particular, the deployment means 22 comprise a fixing member 46 associated with each anchor line 21. Thus, the deployment means 22 advantageously comprise at least three fixing members 46, in particular five fixing members 46.

In a preferred embodiment, each fastener 46 is disposed on the central column 24.

Each fixing member 46 is intended to releasably fix the distal end 42 of the associated anchor line 21 so that a portion of the anchor line 21 extends between the central column 24 and the corresponding stabilization 26 before the mooring of the float 14.

Each fixing member 46 is arranged in the upper part 36 of the float 14.

Alternatively, each fastener 46 is intended to releasably secure the associated anchor line 21 at a region of the anchor line 21 located between 5 m and 20 m from the distal end 42. part of said anchoring line 21 located between the distal end 42 and the region fixed to the fixing member 46 is wound around a dedicated device arranged on the central column 24, in particular around the winch 48.

In an advantageous embodiment, the deployment means 22 comprise a single winch 38 capable of cooperating with all the anchor lines 21.

The winch 48 is a system capable of cooperating with the distal end 42 of one of the anchor lines 21 and capable of winding and unwinding the anchor line 21 around a fixed axis.

The winch 48 is advantageously motorized and advantageously has a power of between 10 kW and 20 kW, in particular between 14 kW and 16 kW.

As a variant, the winch 48 is actuated by an operator by means of a crank placed on the winch 48.

The winch 48 is suitable for adjusting the length of the portion of the anchor line 21 extending between the central column 24 and the stabilization column 26.

In particular, the winch 48 is suitable for reducing the length of this portion by winding the distal part of the anchor line 21 around the axis of the winch 48. Similarly, the winch 48 is suitable for increasing the length of this portion by unrolling the distal part of the anchor line 21 from the winch shaft 48.

The winch 48 is advantageously arranged on a platform fixed to the central column 24. The winch 48 is able to be moved on this platform in order to cooperate with the various anchor lines 21.

The deployment means 22 advantageously comprise at least one guide member 50 associated with the or each anchor line 21 arranged on the stabilization column 26 corresponding to the anchor line 21 or on the pontoon 20 associated with said stabilization column 26.

In particular, the deployment means 22 advantageously comprise at least two guide members 50 for the or each anchor line 21.

For the or each anchor line 21, the two guide members 50 comprise a first guide member 50 arranged on the corresponding stabilization column 26 and a second guide member 50 arranged on the pontoon 20 associated with said stabilization column 26 .

The two guide members 50 are suitable for cooperating with the associated anchoring line 21 so that the anchoring line 21 extends from the fixing device 44 of the stabilization column 26 to the fixing member 46 of the central column 24 along the pontoon 20 and up the central column 24 along the main axis A-A'.

The first guide member 50 is arranged on the corresponding stabilization column 26 opposite the pontoon 20.

The first guide member 50 is arranged in the lower part 34 of the float 14.

The second guide member 50 is arranged on the pontoon 20 associated with the corresponding stabilization column 26, in particular on one of the side faces 32 of said pontoon 20.

The second guide member 50 is arranged in the lower part 34 or in the intermediate part 38 of the float 14.

At least one of the guide members 50 has for example the shape of a bollard comprising a cylindrical part projecting from the wall of the float 14 and a head arranged at the free end of the cylindrical part.

As a variant or in addition, at least one of the guide members 50 comprises two parallel plates projecting out of the float and capable of receiving the anchor line 21 between the two plates.

The deployment means 22 include, for each anchor line 21, an associated buoy 52.

Each buoy 52 is fixed at the level of the distal end 42 of the corresponding anchor line 21.

“Attached at the distal end” means attached at the distal end or attached at a distance of less than 1 m from the distal end.

Each buoy 52 is capable of causing the distal end 42 of the corresponding anchor line 21 to float at the level of the surface S of the expanse of water.

Alternatively, each buoy 52 is attached to the central column 24. Each buoy 52 is able to be disconnected from the central column 24 and to be attached to the associated anchor line 21.

A method of anchoring the wind turbine assembly 10 will now be described.

The following method will be described for a single anchor line 21. Those skilled in the art will understand that this method is similarly applicable to any number of anchor lines 21.

Initially, the wind turbine assembly 10 is in the non-operational state.

The wind turbine assembly 10 is for example located in a port.

The anchor line 21 is fixed permanently to the corresponding stabilization column 26 by means of the fixing device 44 of said stabilization column 26.

The anchor line 21 is engaged with the two associated guide members 50 and fixed to the central column 24 by means of the fixing member 46.

Then winch 38 is connected with anchor line 21.

The winch 38 decreases the length of the portion of anchor line 21 extending between the central column 24 and the stabilization column 26 in order to tension the anchor line 21 and that the latter runs along the corresponding pontoon 20, as seen in figure 2.

Winch 38 is then disconnected from anchor line 21.

Then, the wind turbine assembly is towed by a tug, for example to the operating site.

When the wind turbine assembly 10 is located at the operating site, the method includes a step of connecting the winch 38 with the anchor line 21.

Then, the winch 38 increases the length of the portion of anchor line 21 extending between the central column 24 and the stabilization column 26 in order to relax the anchor line 21 and that it hangs under the pontoon. 20 corresponding, as shown in Figure 3.

Winch 38 is then disconnected from anchor line 21.

Then the method includes a step of releasing the distal end 42 of the anchor line 21. In particular, the fixing member 46 releases the distal end 42 of the anchor line 21.

The distal end 42 then floats on the surface S of the expanse of water by means of the associated buoy 52, as shown in Figure 4.

Then, a boat recovers the floating distal end 42 and disconnects the buoy 52.

Then the boat connects the anchor line 21 with an anchor cable 54 having one end fixed to the seabed 56, as shown in Figure 5.

The wind turbine assembly 10 is thus anchored to the seabed 56 by means of the anchor line 21.

The draft T is adjusted by introducing ballast in the columns 24, 26 and in the pontoons 20.

The wind turbine assembly 10 is then in the operational state and is capable of producing electricity.

In the event of the need for a maintenance operation on the wind turbine assembly 10, the anchor line 21 is detached from the anchor cable 54 and reattached to the central column 24 by means of the fixing member 46.

Then, the wind turbine assembly 10 is towed by the tug to the port where the maintenance operations are carried out.

It can then be seen that the invention has a certain number of advantages.

First of all, the invention allows easy anchoring on the operating site, without the presence of motorized devices and operators on the stabilization columns 26. Indeed, all the operations of the anchoring method according to the invention are carried out from the central column 24 and/or from a boat outside the float 14.

The invention also allows easy towing without the anchor lines 21 disturbing the navigation of the float 14 during this phase.

The invention also allows reversibility of the method by reattaching the distal end 42 to the attachment member 46 on the platform during installation or before towing the wind turbine assembly 10 to a port in the event of maintenance. heavy to carry out or when dismantling the wind turbine.

In addition, the deployment means 22 according to the invention adapt easily to any float 14 and are easily installed thereon.

The deployment means 22 according to the invention are also simple, reliable and robust, which is particularly advantageous so as not to limit the operating time of the wind turbine assembly 10.

Finally, the deployment means 22 are advantageously used for other operations such as lifting and connecting the electric cables connecting the various wind turbines of a wind farm, thus making it possible to significantly reduce the cost of anchoring the wind turbine assembly 10 as well as a reduction in the equipment necessary to embark on the float 14.

Claims (10)

Semi-submersible wind turbine float (14) capable of floating on a surface (S) of a body of water and defining a lower part (34) intended to be submerged and an upper part (36) intended to be emerged, the float (14) comprising:
- a central column (24) extending along a main axis (A-A') and capable of supporting a wind turbine (12);
- at least two stabilization columns (26) of the float (14), each stabilization column (26) extending along an axis substantially parallel to the main axis (A-A') of the central column (24);
- at least two pontoons (20), each stabilization column (26) being connected to the central column (24) by one of the pontoons (20); and
- at least one anchor line (21) associated with one of the stabilization columns (26) and defining a proximal end (40) permanently fixed to this stabilization column (26) and a distal end (42) intended to be attached directly or indirectly to the seabed (56) when the float (14) is moored;
characterized in that the float (14) further comprises deployment means (22) of the or each anchor line (21) comprising:
+ for the or each anchor line (21), at least one fixing member (46) intended to releasably fix the distal end (42) of this anchor line (21) in such a way that a portion of this anchor line (21) extends between the central column (24) and the corresponding stabilization column (26) before the mooring of the float (14); and
+ a winch (48) capable of adjusting the length of this portion of the anchor line (21). Float (14) according to Claim 1, in which the deployment means (22) comprise at least three anchor lines (21), in particular five anchor lines (21), each stabilization column (26) receiving at least one of the anchor lines (21). Float (14) according to Claim 1 or 2, in which the or each fixing member (46) is arranged in the upper part of the float (14). Float (14) according to any one of the preceding claims, in which the deployment means (22) comprise, for each anchor line (21), at least one guide member (50) for the anchor line ( 21) arranged on the corresponding stabilization column (26) or on the pontoon (20) associated with said stabilization column (26). Float (14) according to Claim 4, in which the deployment means (22) comprise, for each anchor line (21), at least two guide members (50) including a first guide member (50) arranged on the corresponding stabilization column (26) and a second guide member (50) disposed on the pontoon (20) associated with said stabilization column (26). Float (14) according to any one of the preceding claims, in which the deployment means (22) comprise, for each anchor line (21), a buoy (52) fixed at the level of the distal end (42) of the anchor line (21). Wind turbine assembly (10) comprising:
- a float (14) according to any one of the preceding claims; and
- a wind turbine (12) supported by the central column (24) of the float (14). A method of anchoring a wind turbine assembly (10) according to claim 7 floating on a surface (S) of a body of water, each anchor line (21) extending between the central column (24 ) and the corresponding stabilization column (26), the method comprising, for each anchor line (21), at least the following steps:
- connection of the winch (48) with the anchor line (21) associated;
- increasing the length of the anchor line portion (21) extending between the central column (24) and the stabilization column (26) by means of the winch (48);
- disconnection of the anchor line (21) with the winch (48); and
- anchoring the wind turbine assembly (10) to the seabed (56) by means of the anchor line (21). Method of anchoring according to claim 8, the float (14) being according to claim 6, in which the method of anchoring comprises, between the step of disconnecting and the step of anchoring, for each anchor line ( 21), a step of releasing the distal end (42) from the anchor line (21), the distal end (42) floating on the surface (S) of the expanse of water by means of the buoy (52). Anchoring method according to claim 8 or 9, in which the anchoring step comprises, for each anchor line (21), a sub-step of connecting each anchor line (21) with a cable of anchor (54) having one end fixed to the seabed (56).