Offshore wind turbine generator with tensioned guide wire

Abstract

An offshore wind turbine generator (1) is disclosed, comprising a lifting device for lifting a main component (6) onto / from a nacelle (4). The lifting device comprises a tower crane (5) and at least two tensioned guide lines (9), each guide line (9) being connected at a first end to an on-tower position (10) of the offshore wind turbine generator (1) and at an opposite second end to a sub-tower position (2) of the offshore wind turbine generator (1). At least one guide element (12) interconnects a connection interface (8) and / or the main component (6) to each guide line (9). A tensioning system (11) introduces tension in each guide line (9) and also suppresses oscillating motion of the suspended main component (6) in a direction substantially transverse to the direction defined by the movement path defined by the guide lines (9).

Description

Technical Field

[0001] This invention relates to an offshore wind turbine generator having a lifting device for hoisting main components onto / from the tower position, such as hoisting them to / from the nacelle. The main components being hoisted or lowered are guided by tensioned guide lines. The offshore wind turbine generator according to the invention allows the oscillating motion of the main components being hoisted or lowered to be properly handled without introducing excessive tension into the tensioned guide lines. Background Technology

[0002] Wind turbine generators typically contain several heavy major components, such as gearboxes, generators, transformers, and main bearings. These major components are usually located in or near the nacelle atop the tower. Therefore, when replacing one of these major components, the component to be replaced needs to be lowered from the nacelle, and the replacement component needs to be hoisted into the nacelle for installation. This requires suitable lifting equipment, such as cranes with sufficient lifting capacity to handle the weight of the major components. Furthermore, the major components need to be guided during lowering or hoisting to ensure they are lowered or hoisted in a controlled manner, for example, minimizing the risk of collision with the tower and / or nacelle structure.

[0003] For onshore wind turbines, ground cranes and ground guidance systems (such as ropes) can be used to lower and lift major components from and onto the nacelle. However, this is not an option for offshore wind turbines. Therefore, for offshore wind turbines, it is desirable to use tower cranes, such as those located in or on the nacelle, or those positioned on the tower near the top. However, this introduces the risk of collision between the lowered or lifted major components and the wind turbine tower. Furthermore, this risk is further increased because offshore wind turbines are expected to be exposed to wind and wave impacts more significantly than onshore wind turbines. Summary of the Invention

[0004] One object of embodiments of the present invention is to provide an offshore wind turbine generator with a lifting device, wherein the risk of collision between the main components being lowered or lifted from the nacelle and the tower is minimized without introducing excessive loads onto the wind turbine generator.

[0005] Another object of embodiments of the present invention is to provide a method for replacing major components in the nacelle of an offshore wind turbine generator, wherein the risk of collision between the major components being lowered or lifted from the nacelle and the tower is minimized without introducing excessive loads onto the wind turbine generator.

[0006] According to a first aspect, the present invention provides an offshore wind turbine generator, the offshore wind turbine generator including a foundation, a tower supported by the foundation, a nacelle mounted on the tower, and a lifting device for lifting major components to / lowering major components from the nacelle, wherein the lifting device includes: - A tower crane, which is arranged in or on a nacelle, and includes a connection interface for connecting the suspended main component to the tower crane; - At least two tensioned guide lines, each guide line being connected at a first end to a position on the tower of the offshore wind turbine generator and at the opposite second end to a position under the tower of the offshore wind turbine generator. - A tensioning system configured to introduce tension in each guide wire; and - At least one guiding element interconnects the connection interface and / or main components with the guide lines, so that the suspended main components, which are lifted or lowered by a crane on a tower, can be guided along the movement path by means of the guide lines. The tensioning system is also configured to suppress, during use, oscillating motion of the suspended main components in a direction substantially transverse to the direction defined by the movement path.

[0007] Therefore, according to a first aspect, the present invention provides an offshore wind turbine generator. In this context, the term "offshore wind turbine generator" should be interpreted as meaning a wind turbine generator located at an offshore location (e.g., at sea or on a lake).

[0008] Offshore wind turbine generators consist of a foundation, a tower supported by the foundation, and a nacelle mounted on the tower. Several major components (such as gearboxes, generators, transformers, main bearings, etc.) are housed in the nacelle.

[0009] Offshore wind turbine generators also include lifting devices for hoisting major components into / from the nacelle, for example as part of a process to replace one of the major components housed in the nacelle.

[0010] The lifting device includes a tower crane arranged in or on the nacelle, at least two tensioned guide lines, and a tensioning system. The tower crane includes a connection interface for attaching a main component to the tower crane, thereby allowing the main component to be suspended from the tower crane during lowering or lifting. The connection interface may be, for example, in the form of a hook located at the end of the lifting lines, or may be any other suitable type of connection interface that allows the main component to be detachably attached to the tower crane to enable the main component to be lowered or lifted by means of the tower crane.

[0011] At least two guide lines are each connected at a first end to an on-tower location of the offshore wind turbine and at a second, opposite end, to a sub-tower location of the offshore wind turbine. In this context, the term "on-tower location" should be interpreted as a location at or near the top of the tower. Therefore, an on-tower location can be a location on the tower near the top, such as immediately below the nacelle. Alternatively, an on-tower location can be a location on the nacelle. Similarly, in this context, the term "sub-tower location" should be interpreted as a location near the bottom of the tower. Therefore, a sub-tower location can be a location on the tower near the bottom. Alternatively, a sub-tower location can be a location on a foundation, on a transition piece, or on a landing platform near the bottom of the tower. Thus, the tensioned guide lines each interconnect the on-tower location and the sub-tower location of the offshore wind turbine.

[0012] When major components are lowered or lifted from the nacelle to the nacelle using a tower crane, the connecting interface of the tower crane and / or the major components are connected to guide lines via at least one guiding element. Therefore, at least one guiding element is configured to interconnect the major components and / or connecting interfaces to be lowered or lifted (on the one hand) with the guide lines (on the other hand). The major components are thus guided along a movement path defined by the guide lines from a position below the tower to a position above the tower, or from a position above the tower to a position below the tower. The movement path can advantageously be arranged at a suitable distance from the tower to minimize the risk of collision between the major components and the tower.

[0013] Because the connection interface and / or main components are connected to at least two tensioned guide lines, rotation of the main components is essentially avoided during hoisting or lowering.

[0014] The tensioning system is configured to introduce tension in each guide line. The introduced tension ensures that the path of movement followed by the main component is well defined, and that the main component is not allowed to deviate significantly from the path defined by the guide lines. During the use of the lifting device, the tensioning system is also configured to suppress oscillating movement of the suspended main component in a direction substantially transverse to the direction defined by the path of movement. The tensioning system may include separate tensioning mechanisms for each guide line. In this case, the tension introduced in one guide line may differ from the tension introduced in another. Alternatively, all guide lines may be connected to the same tensioning mechanism.

[0015] When the main component being lowered or hoisted is exposed to the impact of wind and waves, it will be pushed away from the path defined by the tensioned guide wire in a direction substantially transverse to the path of movement. This will result in a pull on the guide wire. In this context, the term "substantially transverse" should be interpreted as a direction perpendicular to the direction defined by the path of movement, or at least a direction having a significant component perpendicular to the direction defined by the path of movement. Therefore, a substantially transverse direction is not parallel to or substantially parallel to the direction defined by the path of movement. A substantially transverse direction can, for example, be substantially horizontal.

[0016] The wind and wave impacts on the main components, as described above, can cause them to oscillate in a substantially lateral direction, resulting in periodic tension on the tensioned guide wire. If the tensioned guide wire is simply connected to two fixed ends, this oscillating motion of the suspended main components connected to the guide wire, along with the resulting periodic tension, will cause the guide wire to elongate, leading to a significant increase in tension within it. This will result in significant loads on various components of the wind turbine, such as the guide wire and the components attached to it. Therefore, these components of the wind turbine will need to be designed to withstand these loads. This increases the weight and cost of the wind turbine.

[0017] However, in the wind turbine generator according to the first aspect of the invention, the tensioning system is configured to suppress such oscillating motion of the main components. Therefore, the oscillating motion is handled without introducing excessive tension increase in the guide wires, thereby allowing the affected components of the wind turbine generator to be designed to withstand significantly lower loads. Furthermore, when the main components are not oscillating or when in a position defining a static oscillating motion, the tension introduced in the guide wires is sufficient to ensure proper guidance of the lowered or raised main components. Therefore, the pull on the guide wires caused by the oscillating motion of the main components is handled in such a way that the tension in the guide wires remains substantially constant and the elongation of the guide wires is minimized.

[0018] For example, a tensioning system can be designed such that the deviation of the lowered or raised main component from its path of movement causes energy to be transferred to the tensioning system, rather than causing the guide wire to stretch and thus increase the tension in the guide wire. This can be seen as the tensioning system "absorbing" additional tension that would otherwise be introduced into the guide wire due to the oscillating motion of the suspended main component. This avoids the accumulation of excessive tension in the guide wire. Furthermore, a smaller deviation from the path of movement also prevents slack in the guide wire, thereby reducing the pull on the guide wire. In other words, the tensioning system ensures that a substantially constant tension is maintained in the guide wire.

[0019] The tensioning system may include components connected to the guide wires, which move when the suspended main component oscillates in a substantially lateral direction. According to this embodiment, the oscillating motion of the main component results in periodic pulling on the guide wires, and this periodic pulling causes movement of the components connected to the guide wires, rather than causing elongation of the guide wires and thus an increase in tension in the guide wires. The components may be, for example, counterweights, movable pistons, or any other suitable type of component capable of moving in response to the oscillating motion of the main component connected to the guide wires.

[0020] For example, a tensioning system can be configured such that the movement of the main component away from the resting position of the oscillating motion in a substantially lateral direction results in the transfer of energy from the oscillating motion to the component's movement.

[0021] The oscillating motion of the main component defines a rest position (which substantially coincides with the position on the movement path defined by the guide wires) and two extreme positions (which define the maximum deviation from the movement path on either side of the rest position). When the suspended main component moves away from the rest position toward one of the extreme positions, this results in an increased degree of deviation from the movement path, and thus an increased pull on the guide wires. According to this embodiment, this increased pull on the guide wires causes energy to be transferred from the guide wires to the movement of the components connected to each guide wire. Therefore, energy is transferred from the oscillating motion of the main component to the movement of the components via the guide wires.

[0022] When the main components move in opposite directions, i.e., when they move from one of their extreme positions toward a stationary position, the pull on the guide wires decreases similarly, and as a result, energy can be transferred from the moving components to the individual guide wires to prevent slack in the guide wires.

[0023] Energy transfer can lead to an increase in the potential energy of a moving component. According to this embodiment, when the pull in the guide wire increases due to the oscillating motion of the main component, the moving component is lifted, thereby increasing its potential energy. Similarly, when the main component moves toward a stationary position of the oscillating motion, the moving component can be lowered, thereby reducing its potential energy.

[0024] The energy transfer described above can result in friction between the moving component and an adjacent structure (e.g., in the form of a housing accommodating the moving component). According to this embodiment, energy originating from the oscillating motion of the suspended main component is at least partially absorbed by the moving component and the adjacent structure due to friction between them. Alternatively or additionally, energy transfer can result in friction in other parts of the tensioning system (e.g., in pulleys).

[0025] Alternatively, energy transfer can result in a pressure change in a fluid. For example, the moving component can be a movable piston, and its movement can cause a pressure change in the cylinder housing the movable piston. The fluid can be, for example, hydraulic fluid or air.

[0026] The tensioning system may include at least one constant tension winch. According to this embodiment, tension in the guide wire is provided by the constant tension winch, i.e., a winch that provides substantially constant tension, for example, by winding and unwinding the guide wire in response to changes in the pulling force applied to it. This helps to avoid excessive tension in the guide wire due to increased pulling force, and avoids slack in the guide wire due to decreased pulling force. The constant tension winch can, for example, be actively controlled. Proper control of the constant tension winch can help suppress oscillating movements of the suspended main components. Suppression can also be provided by friction, for example, in one or more pulleys arranged in front of the constant tension winch.

[0027] At least one guiding element may be a rigid element. According to this embodiment, the connection interface and / or the connection between the crane on the tower and the respective guide lines are rigid connections. This ensures that a substantially constant and well-defined distance is maintained between the suspended main components and the respective guide lines, thereby ensuring that the suspended main components are guided in a safe, reliable, and well-defined manner.

[0028] The foundation can be a floating foundation. According to this embodiment, the foundation of the wind turbine is not fixedly connected to the seabed. Instead, the foundation is connected to the seabed or one or more anchor points within the seabed via lines, chains, or similar connectors. Therefore, the exact location of the wind turbine is allowed to move within a specific area defined by the location of one or more anchor points and the length of the connectors, subject to the impact of wind and waves. Furthermore, offshore wind turbines with floating foundations follow the vertical movement of passing waves and may tilt due to wave impact. Therefore, offshore wind turbines with floating foundations are exposed to more wind and wave impacts than offshore wind turbines with fixed foundations. Thus, the risk of oscillating movement of the suspended main components can be considered particularly high in such wind turbines, making the present invention particularly relevant in this case.

[0029] As an alternative, the foundation can be a fixed foundation, such as a jacket, monopile, or other suitable type of bottom-fixed structure.

[0030] The tensioning system can be installed on the foundation at a location below the tower. For example, the location of the tensioning system can define a location where the second end of each guide wire connects to the location below the tower of the offshore wind turbine. This ensures that there is a minimum distance between the movement path defined by the guide wires and the tower. Alternatively, the tensioning system can be installed directly on the tower at a location below the tower. Another alternative is that the tensioning system can be installed on the tower, for example, on or immediately below the nacelle, or on an arm or beam extending from the nacelle, and for example, at a location where the first end of each guide wire connects to the location above the tower of the offshore wind turbine. It should be noted that the offshore wind turbine may include both tensioning systems installed at locations below the tower and tensioning systems installed on the tower.

[0031] The main components to be suspended can be a gearbox, a portion of a gearbox, a generator, a sub-component of a generator, a main bearing, blade bearings, or a transformer. All of these components are relatively heavy, and they are typically located in or near the nacelle. Therefore, it is appropriate to use lifting equipment as described above to lower or lift these components.

[0032] According to a second aspect, the present invention provides a method for replacing major components in the nacelle of an offshore wind turbine generator, the offshore wind turbine generator including a foundation, a tower supported by the foundation, a nacelle mounted on the tower, and a lifting device, the method comprising the following steps: - Remove the main components from their mounting locations in the cabin; - Connects the main components to the crane's tower on the lifting device via the crane's connection interface; - Connecting the connection interface and / or main components to at least two tensioned guide lines of the lifting device via at least one guide element, each guide line being connected at a first end to a position on the tower of the offshore wind turbine generator and at a second, opposite end to a position below the tower of the wind turbine generator; and - Using a crane on the tower, the main components are lowered from the nacelle towards the base of the offshore wind turbine, while at least two tensioned guide lines guide the main components along the movement path. The method further includes the step of introducing tension in the guide wire by means of a tensioning system, wherein, during the lowering of the main component, the tensioning system suppresses oscillating motion of the lowered main component in a direction substantially transverse to the direction defined by the movement path.

[0033] The method according to the second aspect of the invention can be advantageously performed at an offshore wind turbine generator according to the first aspect of the invention. The description set forth above with reference to the first aspect of the invention also applies here.

[0034] In the method according to the second aspect, the main component to be replaced is first removed from its mounting position in the nacelle and may be moved within the nacelle to a location where the removed main component can leave the nacelle. Next, the removed main component is connected to the connection interface of the crane on the tower of the offshore wind turbine generator's lifting device.

[0035] Furthermore, the connection interface and / or the main components connected thereto are connected to at least two tensioned guide lines of the lifting device via at least one guiding element (e.g., at least one rigid guiding element). Each guide line is connected at a first end to a position on the tower of the offshore wind turbine generator and at the opposite second end to a position below the tower of the wind turbine generator. This has already been described above with reference to the first aspect of the invention.

[0036] The main components are then lowered from the nacelle toward the tower of the offshore wind turbine. This is done by properly operating a crane on the tower, while simultaneously guiding the main components using at least two tensioned guide lines. Thus, the main components substantially follow a movement path defined by the guide lines in the manner described above with reference to the first aspect of the invention.

[0037] Furthermore, tension is introduced into the guide wire by means of a tensioning system, and during the lowering of the main component, the tensioning system suppresses oscillating motion of the lowered main component in a direction substantially transverse to the direction defined by the movement path. This has been described in detail above with reference to the first aspect of the invention.

[0038] The tensioning system may include components connected to the guide lines, and the method may further include the step of moving the components as the lowered main component oscillates in a substantially lateral direction. This has been described in detail above with reference to the first aspect of the invention.

[0039] Once the lowering of the main components is complete, the replacement main component can be connected to the connection interface of the crane on the tower, and the replacement main component can be lifted toward the nacelle by the crane on the tower, while being guided by guide lines in essentially the manner described above. Once the replacement main component arrives at the nacelle, it can be installed in the nacelle, thereby replacing the previously lowered main component. Attached Figure Description

[0040] The invention will now be described in more detail with reference to the accompanying drawings, in which: Figure 1 This is a perspective view of an offshore wind turbine generator according to an embodiment of the present invention; Figure 2 and Figure 3 Show Figure 1 Details of the wind turbine generator; Figure 4 and Figure 5 This illustrates the connection between the main components and the lead wires according to an embodiment of the present invention; Figures 6 to 8 A tensioning system for a lifting device of a wind turbine generator according to an embodiment of the present invention is shown; and Figure 9 and Figure 10 The placement of key components as part of a method according to an embodiment of the present invention is shown. Detailed Implementation

[0041] Figure 1 This is a perspective view of an offshore wind turbine generator 1 according to an embodiment of the present invention. The wind turbine generator 1 includes a foundation (not shown) having a landing platform 2. This foundation may be, for example, a floating foundation. A tower 3 is supported by the foundation, and a nacelle 4 is mounted on top of the tower 3. The nacelle 4 houses various major components, such as gearboxes, generators, transformers, and / or main bearings.

[0042] The tower crane 5 is mounted in or on the nacelle 4 and protrudes from the top of the nacelle 4. The main component 6 to be lowered from the nacelle 4 is connected to the tower crane 5 via a line 7 and a connection interface 8 (e.g., in the form of a hook or a similar device that allows the main component 6 to be connected to or attached to the line 7), and thus connected to the lifting mechanism of the tower crane 5. Therefore, the main component 6 is suspended on the tower crane 5.

[0043] The wind turbine generator 1 is also equipped with two tensioned guide lines 9. The guide line 9 is connected at its first end to a beam 10 mounted on the nacelle 4, and thus mounted on the tower, and at its second end to a tensioning system 11 mounted on the landing platform 2, and thus mounted below the tower. Therefore, the guide line 9 defines the path of movement between the tower position at the beam 10 and the tower position at the landing platform 2. The beam 10 ensures that the guide line 9, and thus the path of movement it defines, is arranged with minimal distance from the tower 3.

[0044] The tensioning system 11 introduces tension into each of the guide lines 9. This ensures that the movement path defined by the guide lines 9 remains reliable and well-defined. Furthermore, the tensioning system 11 is configured to suppress oscillating motion of the main component 6 connected to the guide lines 9. This will be described in further detail below.

[0045] Figure 2 and Figure 3 Shown from two different perspectives Figure 1 The details of the wind turbine generator 1 are shown, with a more specific view of the upper part of the wind turbine generator 1. Thus, the crane 5 on the tower, the suspended main components 6, and the connection of the guide wire 9 to the beam 10 can be seen.

[0046] and Figure 2 and Figure 3 similar, Figure 4 Also shown Figure 1 The upper part of the wind turbine generator 1. However, in Figure 4 In this configuration, the main suspended component 6 is connected to each guide line 9 via guide element 12. Thus, when the main suspended component 6 is lowered (or lifted) by crane 5 on the tower, it is guided by the guide lines 9 and therefore follows a movement path defined by the guide lines 9.

[0047] Figure 5 This is a detailed view of the connection between the suspended main component 6 and the guide wire 9. It can be seen that the guide element 12, which interconnects the main component 6 and the guide wire 9, is a rigid element. This ensures a substantially constant or fixed distance between the main component 6 and the guide wire 9.

[0048] Figure 6 Show Figure 1 Another detail of the wind turbine generator 1 is the form of its lower part. Therefore, in Figure 6 Landing platform 2 and tensioning system 11 can be seen in the image. Tensioning system 11 will be referred to below. Figure 7 and Figure 8 Further detailed description.

[0049] Figure 7 and Figure 8 A wind turbine generator 1 according to an embodiment of the present invention is shown (e.g. Figure 1 Tensioning system 11 of the lifting device of the wind turbine generator 1). Figure 7 This is a side view of the tensioning system 11, and Figure 8 This is a three-dimensional view of tensioning system 11.

[0050] The tensioning system 11 includes two movable members 13, in the form of counterweights, each connected to one end of one of the guide lines 9 via a set of pulleys 14. Thus, the weight of the members 13 introduces the required tension in each guide line 9. Furthermore, the pulleys 14 allow the members 13 to move in a substantially vertical direction (i.e., up and down) in response to changes in the pulling force applied to the guide line 9. This will be referred to below. Figure 9 and Figure 10 Further detailed description.

[0051] As part of the method according to an embodiment of the present invention Figure 9 and Figure 10 The main component 6 is shown from Figure 1 The nacelle 4 of the offshore wind turbine generator 1 was lowered. Figure 9 This is a front view of wind turbine generator 1, and Figure 10This is a 3D view of wind turbine generator 1.

[0052] The main component 6 is connected to the crane 5 on the tower via a connection interface 8, and it is also connected via a guide element (not shown) as described above. Figure 4 and Figure 5 The described method connects to each guide line 9. Therefore, when the main component 6 is lowered from a position near the beam 10 toward the landing platform 2 by properly operating the crane 5 on the tower, the main component 6 is guided by the tensioned guide lines 9, thus substantially following the movement path defined by the guide lines 9. This avoids collisions between the main component 6 and the tower 3.

[0053] When the main component 6 is lowered, the wind turbine generator 1 and the main component 6 are exposed to wind and waves. This may cause the main component 6 to deviate from the movement path defined by the guide line 9 in a direction that is substantially transverse to the direction of movement, such as in a substantially horizontal direction. This may further cause the main component 6 to oscillate along this transverse direction.

[0054] This oscillating motion defines a rest position and two extreme positions on opposite sides of the rest position. When the main component 6 moves away from the rest position toward one of the extreme positions, due to the guiding element ( Figure 4 and Figure 5 The connection established in 12) pulls the guide wire 9, such as Figure 9 and Figure 10 As shown. This results in a pulling force on the guide wire 9. If the guide wire 9 is fixedly connected to the wind turbine generator 1 both at its position on the tower and at its position below the tower, this pulling force will cause the guide wire 9 to elongate, resulting in a significant increase in tension within the guide wire 9. This will, for example, require that the various components of the wind turbine generator 1 (particularly the beam 10 and the guide wire 9) be designed and sized to withstand this increased tension.

[0055] However, as mentioned above Figure 7 and Figure 8 As described, the guide wire 9 is connected to the movable member 13 of the tensioning system 11. Therefore, when a pulling force is applied to the guide wire 9 due to the oscillating motion of the suspended main component 6, this pulling force is transferred to the tensioning system 11, causing the member 13 to move in an upward direction, thereby increasing its potential energy. Thus, the tension in the guide wire 9 does not increase, or only increases slightly. This can be considered as the tensioning system 11 “absorbing” the potential increase in tension in the guide wire 9 caused by the oscillating motion of the main component 6.

[0056] As the main component 6 moves from its extreme position toward its rest position as part of the oscillating motion, the pulling force applied to the guide wire 9 gradually decreases. This is balanced by the movable component 13, such that gravity acting on component 13 partially overcomes the reduced pulling force, causing component 13 to move in a downward direction. This ensures that the tension in the guide wire 9 also remains at a substantially constant level during this portion of the oscillating motion, thus preventing slack in the guide wire 9.

[0057] Therefore, the risk of collision between the main component 6 and the tower 3 is minimized without introducing excessive loads on the wind turbine generator 1 (especially the guide wire 9 and the beam 10), and therefore there is no need to design and size the wind turbine generator 1 to withstand such excessive loads.

Claims

1. An offshore wind turbine generator (1) comprising a foundation, a tower (3) supported by the foundation, a nacelle (4) mounted on the tower (3), and a lifting device for lifting main components (6) onto / lowering main components (6) from the nacelle (4), wherein, The lifting device includes: - A tower crane (5) arranged in or on the nacelle (4), the tower crane (5) including a connection interface (8) for connecting the suspended main component (6) to the tower crane (5). - At least two tensioned guide wires (9), each guide wire (9) is connected at a first end to a position (10) on the tower of the offshore wind turbine generator (1) and at the opposite second end to a position (2) below the tower of the offshore wind turbine generator (1). - Tensioning system (11), which is configured to introduce tension in each guide wire (9); and - At least one guiding element (12) interconnects the connection interface (8) and / or the main component (6) with each guide line (9) so that the suspended main component (6), which is lifted or lowered by means of the crane (5) on the tower, can be guided along the movement path by means of the guide lines (9). The tensioning system (11) is also configured to suppress, during use, oscillating motion of the suspended main component (6) in a direction substantially transverse to the direction defined by the movement path.

2. The offshore wind turbine generator (1) according to claim 1, wherein, The tensioning system (11) includes a component (13) connected to each guide line (9), which moves when the suspended main component (6) oscillates in a substantially transverse direction.

3. The offshore wind turbine generator (1) according to claim 2, wherein, The tensioning system (11) is configured such that the movement of the main component (6) away from the rest position of the oscillating motion in the substantially transverse direction results in the transfer of energy from the oscillating motion to the component (13).

4. The offshore wind turbine generator (1) according to claim 3, wherein, Energy transfer results in an increase in the potential energy of the moving component (13).

5. The offshore wind turbine generator (1) according to claim 3 or 4, wherein, Energy transfer causes friction between the moving component (13) and the adjacent structure.

6. The offshore wind turbine generator (1) according to claim 3, wherein, Energy transfer causes pressure changes in the fluid.

7. The offshore wind turbine generator (1) according to any one of the preceding claims, wherein, The tensioning system (11) includes at least one constant tension winch.

8. The offshore wind turbine generator (1) according to any one of the preceding claims, wherein, The at least one guiding element (12) is a rigid element.

9. The offshore wind turbine generator (1) according to any one of the preceding claims, wherein, The basis mentioned is a floating basis.

10. The offshore wind turbine generator (1) according to claim 8, wherein, The tensioning system (11) is installed under the tower on the foundation.

11. The offshore wind turbine generator (1) according to any one of the preceding claims, wherein, The suspended main component (6) is a gearbox, a part of a gearbox, a generator, a main bearing, a blade bearing, or a transformer.

12. A method for replacing a major component (6) in the nacelle (4) of an offshore wind turbine generator (1), the offshore wind turbine generator (1) comprising a foundation, a tower (3) supported by the foundation, a nacelle (4) mounted on the tower (3), and a lifting device, the method comprising the following steps: - Remove the main component (6) from its mounting position in the cabin (4); - Connect the main component (6) to the connection interface (8) of the crane (5) on the tower of the lifting device. - Connect the connection interface (8) and / or the main component (6) to at least two tensioned guide lines (9) of the lifting device via at least one guide element (12), each guide line (9) being connected at a first end to a position (10) on the tower of the offshore wind turbine generator (1) and at the opposite second end to a position (2) below the tower of the wind turbine generator (1); and - The main component (6) is lowered from the nacelle (4) toward the tower of the offshore wind turbine generator (1) by means of the crane (5) on the tower, while the main component (6) is guided along the movement path by means of the at least two tensioned guide lines (9). The method further includes the step of introducing tension in the guide line (9) by means of a tensioning system (11), and wherein, during the lowering of the main component (6), the tensioning system (11) suppresses oscillating motion of the lowered main component (6) in a direction substantially transverse to the direction defined by the movement path.

13. The method according to claim 12, wherein, The tensioning system (11) includes a component (13) connected to each guide line (9), and the method further includes the step of moving the component (13) when the lowered main component (6) oscillates in a substantially transverse direction.

Images