Method and apparatus for handling a wind turbine component

Abstract

A method for handling a wind turbine component (26) is provided. The method includes providing a lifting yoke (38) having a yoke frame (40) and connecting the yoke frame (40) to the wind turbine component (26). The method further includes providing a first crane (24, 36) and attaching the first crane (24, 36) to a first crane interface (44, 46) on the lifting yoke (38). The wind turbine component (26) is suspended in the air by the first crane (24, 36). The method further includes providing a second crane (36, 24) and attaching the second crane (36, 24) to a second crane interface (46, 44) on the lifting yoke (38). Support of the wind turbine component (26) transitions from the first crane (24, 36) to the second crane (36, 24) while the wind turbine component (26) is suspended in the air. Transitioning support of the wind turbine component (26) includes moving the first crane interface (44, 46) and second crane interface (46, 44). A lifting yoke (38) for handling a wind turbine component (26) using a first crane (24, 36) and a second crane (36, 24) is also provided.

Description

[0001] METHOD AND APPARATUS FOR HANDLING A WIND TURBINE COMPONENT

[0002] Technical Field

[0003] This application relates generally to wind turbines, and more particularly to a method and apparatus for transferring a load (e.g., a wind turbine component) between two cranes.

[0004] Background

[0005] Wind turbines are used to produce electrical energy using a renewable resource and without combusting a fossil fuel. Generally, a wind turbine converts kinetic wind energy into mechanical energy and then subsequently converts the mechanical energy into electrical energy. A common type of wind turbine is a single rotor upwind horizontalaxis wind turbine (HAWT). An exemplary single-rotor HAWT includes a tower, a nacelle located at the apex of the tower, and a single rotor having a central hub and one or more blades mounted to the hub and extending radially therefrom and supported in the nacelle by means of a shaft. The rotor may be coupled either directly or indirectly with a generator housed inside the nacelle and configured to convert the mechanical rotation of the rotor to electrical energy. Consequently, as wind forces the blades to rotate, electrical energy is produced by the generator. Wind turbines may be located either on a land mass (e.g., onshore) or within a body of water (e.g., offshore).

[0006] The working life of many wind turbine components may be less than the working life of the wind turbine. Over time, the wind turbine components, such as the generator, gearboxes, heat exchanges, electrical transformer, and the like, may have to be repaired or replaced. However, it can be difficult, time consuming, and expensive to remove and replace these various components — particularly for an offshore wind turbine. To facilitate repair or replacement processes, the nacelle may include or be fitted with a crane configured to lower worn or non-functioning components from the nacelle and lift repaired or replacement components up to the nacelle. The process of transporting wind turbine components to and from the wind turbine as well as lifting / lowering the wind turbine components to / from the nacelle may be relatively straightforward with an onshore wind turbine, as the ground does not move relative to the wind turbine. But, when the wind turbine is offshore, transporting and lowering / lifting wind turbine components can be exceedingly challenging. In existing approaches, service vessels may physically connect to the wind turbine itself or to a floating foundation of the wind turbine with elaborate and complex linkages to allow the service vessel to accommodate the moving water around the wind turbine or floating foundation while the wind turbine components are being lowered and raised by a crane. These elaborate and complex linkages are expensive to design, install, maintain, and operate, which increases the cost of the repair or replacement process. Furthermore, if the water in which the wind turbine or floating foundation resides is turbulent, it may be difficult to safely connect to the wind turbine or floating foundation without possibly damaging the wind turbine.

[0007] Accordingly, there is a need in the wind turbine industry for an improved system and method that facilitates replacement or repair of various wind turbine components during the life of an offshore wind turbine. Preferably, the invention avoids, alleviates, mitigates, or otherwise minimizes one or more of the various drawbacks or shortcomings of existing systems and methods for the same.

[0008] Summary

[0009] Certain exemplary aspects of the invention are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention.

[0010] In a first aspect of the invention, a method for handling a wind turbine component is disclosed. The method includes providing a lifting yoke having a yoke frame configured to be connected to the wind turbine component and connecting the yoke frame to the wind turbine component. The method further includes providing a first crane and attaching the first crane to a first crane interface on the lifting yoke and supporting the wind turbine component with the first crane so that the wind turbine component is suspended in the air and substantially an entire weight of the wind turbine component is being supported by the first crane. The method additionally includes providing a second crane, attaching the second crane to a second crane interface on the lifting yoke, and transitioning support of the wind turbine component from the first crane to the second crane while the wind turbine component is suspended in the air such that substantially the entire weight of the wind turbine component is supported by the second crane. Transitioning support of the wind turbine component from the first crane to the second crane includes moving the first and second crane interfaces relative to the yoke frame while transitioning support of the wind turbine component from the first crane to the second crane.

[0011] In one embodiment, transitioning support of the wind turbine component from the first crane to the second crane may further include maintaining a substantially level orientation of the lifting yoke while transitioning support of the wind turbine component from the first crane to the second crane. Additionally, in one embodiment, moving the first and second crane interfaces relative to the yoke frame may further include moving the first crane interface from a first position to a second position and moving the second crane interface from a third position to a fourth position. Further, the wind turbine component may include a center of gravity and in one embodiment, when the first crane interface is in the first position, the first crane interface may be substantially vertically aligned with the center of gravity of the wind turbine component and when the second crane interface is in the fourth position, the second crane interface may be substantially vertically aligned with the center of gravity of the wind turbine component. Furthermore, in one embodiment, the method may also include reducing the load carried by the first crane and increasing the load carried by the second crane in coordination with movement of the first crane interface from the first position to the second position and the second crane interface from the third position to the fourth position.

[0012] In one embodiment, moving the first crane interface relative to the yoke frame may further include energizing at least one actuator to move the first crane interface and moving the second crane interface relative to the yoke frame may further include energizing the at least one actuator to move the second crane interface. In one embodiment, the lifting yoke may include a slide mechanism to which the first crane interface and the second crane interface are connected. In this embodiment, moving the first and second crane interfaces may include energizing at least one actuator to move the slide mechanism between a first slide location and a second slide location. In an alternative embodiment, the at least one actuator may include a first actuator connected to the first crane interface (e.g., via a first slide mechanism) and a second actuator connected to the second crane interface (e.g., via a second slide mechanism). In this embodiment, moving the first crane interface and the second crane interface may include moving the first crane interface relative to the yoke frame by energizing the first actuator and moving the second crane interface relative to the yoke frame by energizing the second actuator. In one embodiment, energizing the at least one actuator, such as the first and second actuator, may include remotely energizing the at least one actuator.

[0013] In one embodiment, attaching the second crane to the second crane interface may further include attaching the second crane to the second crane interface while the wind turbine component is suspended in the air. Additionally, in one embodiment, the method may further include detaching the first crane from the first crane interface after the second crane is attached to the second crane interface and substantially the entire weight of the wind turbine component is supported by the second crane. Further, in one embodiment, the method may include providing a warning when an inclination of the lifting yoke exceeds a predetermined threshold while transitioning the support of the wind turbine component from the first crane to the second crane.

[0014] In one embodiment, the handling of the wind turbine component may be a lifting process of the wind turbine component to a top of a wind turbine tower. In this embodiment, providing the first crane may include providing a ship crane and providing the second crane may include providing a nacelle crane. In an alternative embodiment, the handling of the wind turbine component may be a lowering process of the wind turbine component from a top of a wind turbine tower. In this embodiment, providing the first crane may include providing a nacelle crane and providing the second crane may include providing a ship crane.

[0015] In another aspect of the invention, a lifting yoke for handling a wind turbine component using a first crane and a second crane is disclosed. The lifting yoke includes a yoke frame configured to be connected to the wind turbine component. The lifting yoke further includes a first crane interface movably connected to the yoke frame and configured to be connected to the first crane. The lifting yoke further includes a second crane interface movably connected to the yoke frame, spaced from the first crane interface, and configured to be connected to the second crane. Further, the lifting yoke includes at least one actuator for moving the first crane interface between a first position and a second position and for moving the second crane interface between a third position and a fourth position. The first position of the first crane interface is configured to be vertically aligned with a center of gravity of the wind turbine component. The fourth position of the second crane interface is configured to be vertically aligned with the center of gravity of the wind turbine component.

[0016] In one embodiment, the first crane interface may be connected to the second crane interface such that movement of the one of the first or second crane interface causes movement of the other of the first or second crane interface. In one embodiment, for example, the first crane interface and the second crane interface may be attached to a slide mechanism of the lifting yoke.

[0017] In an alternative embodiment, the first crane interface and the second crane interface may be moveable independently of each other. For example, in one embodiment, the at least one actuator may include a first actuator connected to the first crane interface and a second actuator connected to the second crane interface. The first and second actuators may be operable independently of each other to control movement of the first and second crane interfaces, respectively.

[0018] In one embodiment the lifting yoke may further include an inclination warning system configured to provide a warning when an inclination of the lifting yoke exceeds a predetermined threshold while transitioning support of the wind turbine component from the first crane to the second crane.

[0019] Brief Description of the Drawings

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the Detailed Description given below, serve to explain the one or more embodiments of the invention.

[0021] Fig. 1 is a perspective view of an offshore wind turbine with a service vessel positioned adjacent thereto according to an embodiment of the disclosure. Fig. 2 is a front view of a lifting yoke according to an embodiment of the disclosure.

[0022] Fig. 3 is a further front view of the lifting yoke of Fig. 2, showing a first crane interface in a first position and a second crane interface in a third position.

[0023] Fig. 4 is a further front view of the lifting yoke of Fig. 2, showing the first crane interface in a second position and the second crane interface in a fourth position.

[0024] Fig. 5 is a front view of a lifting yoke according to an alternative embodiment of the disclosure, showing the first crane interface in the first position and the second crane interface in the third position.

[0025] Fig. 6 is a further front view of the lifting yoke of Fig. 5, showing the first crane interface in the second position and the second crane interface in the fourth position.

[0026] Detailed Description

[0027] The exemplary embodiments described herein are provided for illustrative purposes and are not limiting. Other exemplary embodiments are possible, and modifications may be made to the exemplary embodiments within the scope of the present disclosure. Therefore, this Detailed Description is not meant to limit the scope of the present disclosure.

[0028] With reference to the figures generally, aspects of the invention include a method and apparatus for transferring a load (e.g., a wind turbine component) from one crane (e.g., a vessel crane) to another crane (e.g., a nacelle crane) in the air without the need for a support structure (e.g., a transfer platform attached to the wind turbine tower) beneath the load. Advantageously, the invention, described in greater detail below, addresses issues and complications of exchanging a wind turbine component between a service vessel and an offshore wind turbine without unnecessarily wasting lifting height of the service vessel crane or the nacelle crane, thus maximizing the possible lift height of the load. Other advantages and technical effects of the embodiments of this invention will become evident to one skilled in the art from the following description. With reference to Fig. 1 , an exemplary offshore wind turbine 10 is shown. The wind turbine 10, which is represented as a horizontal-axis wind turbine (HAWT), includes a tower 12 and an energy generating unit 14 disposed at the apex of the tower 12. The tower 12 may be coupled to a foundation (not shown) at a lower end thereof. As in the depicted embodiment, the foundation may extend underwater and be supported by the seabed. Alternatively, the foundation may be a floating foundation generally disposed on top of the water. An end of the wind turbine 10, opposite the energy generating unit 14, is fixedly secured to the foundation.

[0029] The tower 12 supports the weight of the energy generating unit 14 and operates to elevate the energy generating unit 14 to a height above sea level at which faster moving air currents of lower turbulence are typically found. The energy generating unit 14 transforms the energy of the wind into electrical energy. The energy generating unit 14 typically includes a nacelle 16, a rotor 18 having a rotor hub 20, and wind turbine blades 22 mounted to the rotor hub 20 extending radially therefrom at locations circumferentially distributed thereabout. In the depicted embodiment, the rotor 18 includes three blades 22, but the number may vary. The blades 22 are configured to interact with the passing air flow to produce lift that causes the rotor hub 20 to spin about a longitudinal axis. During operation, the wind produces lift and causes the rotor 18 to spin or rotate to generally define a sweep area of the wind turbine blades 22. The energy generating unit 14 generates power from the wind that passes through the swept area of the rotor 18.

[0030] With continued reference to Fig. 1 , the energy generating unit 14 may further include a drive train with a generator (not shown) for converting mechanical energy into electrical energy, optionally via a gear arrangement (not shown). A substantial portion of the drive train may be positioned inside of the nacelle 16 of the wind turbine 10. In addition to the generator, the nacelle 16 typically houses miscellaneous components required for converting wind energy into electrical energy and various components needed to maintain, operate, control, and optimize the performance of the wind turbine 10.

[0031] A nacelle crane 24 may be positioned in or on the nacelle 16 and is configured to lift a wind turbine component 26 up to the nacelle 16 or lower a wind turbine component 26 down from the nacelle 16. For example, the movement of a wind turbine component 26 may be part of a repair or replacement process for the offshore wind turbine 10, as described above. The movement of the wind turbine component 26 may alternatively be part of an original installation of the wind turbine 10. Wind turbine component 26 should be broadly understood to include anything that may need to be lifted to or lowered from an up-tower location of the wind turbine 10 — and, particularly, lifted to or lowered from the nacelle 16. In one embodiment, the nacelle crane 24 may permanently reside in or on the nacelle 16. In an alternative embodiment, however, the nacelle crane 24 may be temporary and connected to the nacelle 16 for the specific purpose of installing or replacing the wind turbine component 26.

[0032] With continued reference to Fig. 1 , a service vessel 28 may be positioned near to the offshore wind turbine 10. The service vessel 28 may be a small jack-up vessel. As described in greater detail below, the service vessel 28 may include a lifting apparatus. Further, the service vessel 28 does not need to be physically attached to the wind turbine 10 to transfer wind turbine components 26 to / from the wind turbine 10. This is in contrast to many existing arrangements where the system for handling the wind turbine components 26 is physically connected directly to the wind turbine 10. Instead, the service vessel 28 may be located a distance, D, from the closest portion of the wind turbine 10.

[0033] The nacelle crane 24 on the nacelle 16 has a working zone 30 in which the nacelle crane 24 can lift or lower wind turbine components 26 to or from the nacelle 16. The outer most perimeter of the working zone 30 is a maximum working distance 32, which is the farthest distance that a lift line 34 of the nacelle crane 24 can reach. The distance D of the service vessel 28 from the wind turbine 10 is greater than the maximum working distance 32 of the nacelle crane 24 such that the service vessel 28 is outside of the working zone 30 of the nacelle crane 24. Thus, it is not possible for the nacelle crane 24 to directly access the service vessel 28 and lift the wind turbine component 26 to the nacelle 16, for example. To address this issue, a lifting yoke 38 that facilitates an in-air “handshake” between a vessel crane 36 (or similar) on the service vessel 28 and the nacelle crane 24 is provided (and described in greater detail below). It is one advantage of the invention that the invention allows for the use of a smaller service vessel 28 which does not need to provide a vessel crane 36 capable of lifting a wind turbine component 26 to the nacelle 16 of the wind turbine 10. Instead, the wind turbine component 26 can be lifted to the nacelle 16 by a combination of the vessel crane 36 and the nacelle crane 24. The use of a smaller service vessel 28 incurs significantly less cost, allows for greater flexibility, and minimizes the risk of non-availability.

[0034] Referring now to Fig. 2, the Figure shows an embodiment of the lifting yoke 38 according to an aspect of the disclosure. The lifting yoke 38 includes a yoke frame 40. The yoke frame 40 may be substantially linear in a horizontal direction to minimize the amount of lift height occupied by the yoke frame 40. For example, the yoke frame 40 may be a steel I-beam. It is to be understood that the yoke frame 40 could take on other forms and / or be made of a material other than steel. The yoke frame 40 is configured to be connected to the load (e.g., wind turbine component 26) to be carried by the lifting yoke 38. To that end, the yoke frame 40 includes a load plate 42 on an underside of the yoke frame 40 in the depicted embodiment. As will be described in greater detail below, the load plate 42 is used to secure the load (e.g., a wind turbine component 26) to the lifting yoke 38.

[0035] The yoke frame 40 further includes a first crane interface 44 and a second crane interface 46 located at or near a top portion of the yoke frame 40, in the depicted embodiment. The first crane interface 44 is movably connected to the yoke frame 40 and is configured to be connected to the first crane (e.g., the vessel crane 36). Similarly, a second crane interface 46 is movably connected to the yoke frame 40 and configured to be connected to the second crane (e.g., the nacelle crane 24). The second crane (e.g., the nacelle crane 24) may be attached to the second crane interface 46 while the wind turbine component 26 is suspended in the air (e.g., by the first crane). The second crane interface 46 is spaced from the first crane interface 44 to prevent hooks from the vessel crane 36 and the nacelle crane 24 from coming into contact with each other. In the depicted embodiment, the first crane interface 44 and the second crane interface 46 are both connected to and separated from each other by a slide mechanism 48.

[0036] With continued reference to Fig. 2, the slide mechanism 48 moves (e.g., slides) along the yoke frame 40 between a first slide location (as shown in Fig. 3, for example) and a second slide location (as shown in Fig. 4, for example). When the slide mechanism 48 is in the first slide location, the first crane interface 44 is in a first position and the second crane interface 46 is in a third position. When the slide mechanism 48 is in the second slide location, the first crane interface 44 is in a second position and the second crane interface 46 is in a fourth position. Thus, moving the slide mechanism 48 from the first slide location to the second slide location moves the first crane interface 44 from its first position to its second position, and the second crane interface 46 from its third position to its fourth position. In the depicted embodiment where the yoke frame 40 is substantially linear, the slide mechanism 48 moves in a substantially linear path between the first slide location and the second slide location. In an exemplary embodiment, actuator 50 moves the slide mechanism 48 between the first slide location and the second slide location (and thus the first crane interface 44 between a first position and a second position and the second crane interface 46 between a third position and a fourth position). Such is shown in Figs. 3 and 4, for example, and will be explained in greater detail below. The actuator 50 may be a hydraulic cylinder; however, it is to be understood that the actuator 50 may take on other forms.

[0037] While in the above, the movement of the first crane interface 44 and the second crane interface 46 are interrelated, i.e., through movement of the slide mechanism 48, aspects of the invention are not limited to such an arrangement. In an alternative embodiment (not shown), for example, the first crane interface 44 may be connected to a first slide mechanism and the second crane interface 46 may be connected to a second slide mechanism that is operatively disconnected from the first slide mechanism. Thus, the first crane interface 44 may be moved independently from the second crane interface 46. In this embodiment, for example, each of the first and second slide mechanisms may have a dedicated actuator for controlling the movements of the first and second crane interfaces 44, 46.

[0038] The lifting yoke 38 further includes an inclination warning and protection system 52, as schematically depicted in Fig. 2. The purpose of the inclination warning and protection system 52 is to prevent an unsafe handoff of the load (e.g., wind turbine component 26) from the first crane (e.g., the vessel crane 36) to the second crane (e.g., the nacelle crane 24). The inclination warning and protection system 52 provides a warning when an inclination of the lifting yoke 38 exceeds a predetermined threshold. For example, the inclination warning and protection system 52 may prevent the slide mechanism 48 from moving from the first slide location to the second slide location (or from the second slide location to the first slide location) if the inclination of the lifting yoke 38 exceeds 5°, 10°, 15°, or 20°. Other predetermined threshold angles may also be possible and should not be limited to those provided above. By way of example, the inclination warning and protection system 52 may include a controller having one or more processors and a memory for storing program code. The controller may be operatively connected to one or more inclinometers or tilt sensors located on the lifting yoke 38 and may be further operatively connected to the at least one actuator 50. The controller is configured to receive signals from the one or more inclinometers to determine whether the lifting yoke 38 has deviated from a horizontal orientation by a predetermined threshold. If the lifting yoke 38 has tilted beyond the predetermined threshold, then a warning signal may be initiated (e.g., alarm, sirens, or other audible and / or visible, and / or electronic warning indication). Additionally, or alternatively, the controller may cause the at least one actuator 50 to cease operation.

[0039] Referring now to Figs. 3 and 4, the Figures show the slide mechanism 48 in the first slide location and second slide location, respectively (and thus the first crane interface 44 in the first and second position, respectively, and the second crane interface 46 in the third and fourth position, respectively). In the embodiment depicted in Figs. 3 and 4, the first crane (e.g., the vessel crane 36) is attached to the first crane interface 44 and the second crane (e.g., the nacelle crane 24) is attached to the second crane interface 46. Such an arrangement could be used for transporting a wind turbine component 26 from the service vessel 28 up to the nacelle 16 of the wind turbine 10. However, it is to be understood that an alternative arrangement could be employed. For example, the first crane could be the nacelle crane 24 and the second crane could be the vessel crane 36. Such an arrangement could be used for transporting a wind turbine component 26 from the nacelle 16 of the wind turbine 10 down to the service vessel 28.

[0040] In the first slide location shown in Fig. 3, the first crane interface 44 is substantially vertically aligned with the center of gravity of the wind turbine component 26 suspended from the load plate 42 by rigging 54. In such an arrangement, the wind turbine component 26 is supported primarily or entirely by the first crane (e.g., the vessel crane 36). In other words, when the wind turbine component 26 is suspended in the air while the slide mechanism 48 is in the first slide location (and thus the first crane interface 44 is in the first position, and the second crane interface 46 is in the third position), substantially an entire weight of the wind turbine component 26 is supported by the first crane (e.g., the vessel crane 36).

[0041] With continued reference to Figs. 3 and 4, to transition the slide mechanism 48 from the first slide location to the second slide location (and thus the first crane interface 44 from the first position to the second position, and the second crane interface 46 from the third position to the fourth position), the actuator 50 is energized. The actuator 50 may be remotely energized and / or remotely controlled. The energy may be electric, electro-magnetic, hydraulic, pneumatic, or mechanical energy. The energized system may include a battery or accumulator, an electro-magnet, energy storage means for storing hydraulic or pneumatic energy or spring or other means capable of storing mechanical energy. A combination of two or more different kinds of energy storage may also be used. The actuator 50 may be radio-controlled and activated by a remote control. In the depicted embodiment, energizing the actuator 50 causes a rod 56 to either extend from or retract into a housing 58. The housing 58 is secured to the yoke frame 40 and the rod 56 is secured to the slide mechanism 48. Thus, energizing the actuator 50 causes the slide mechanism 48 to move between the first and second slide locations (and thus the first crane interface 44 to move between the first and second positions, and the second crane interface 46 to move between the third and fourth positions). In Fig. 3, the rod 56 is extended from the housing 58 and the slide mechanism 48 is in the first slide location. In Fig. 4, the rod 56 is retracted into the housing 58 and the slide mechanism 48 is in the second slide location.

[0042] In the second slide location shown in Fig. 4, the second crane interface 46 is substantially vertically aligned with the center of gravity of the wind turbine component 26 suspended from the load plate 42 by rigging 54. In such an arrangement, the wind turbine component 26 is supported primarily or entirely by the second crane (e.g., the nacelle crane 24). In other words, when the wind turbine component 26 is suspended in the air while the slide mechanism 48 is in the second slide location (and thus the first crane interface 44 is in the second position, and the second crane interface 46 is in the fourth position), substantially an entire weight of the wind turbine component 26 is supported by the second crane (e.g., the nacelle crane 24). After the slide mechanism 48 has moved to the second slide location and substantially an entire weight of the wind turbine component 26 is supported by the second crane (e.g., the nacelle crane 24), the first crane (e.g., the vessel crane 36) may be detached from the first crane interface 44. Such may be accomplished remotely with a remotely activatable release mechanism, for example. The remotely activatable release mechanism may be radio controlled and activated by a remote control, for example. Alternatively, the remotely activatable release mechanism may be manually operated (e.g., with a cable or rope) by an operator on the service vessel 28 or at the wind turbine 10. Further, the remotely activatable release mechanism may include a load sensing mechanism allowing the activation of the release mechanism only if the load detected by the load sensing mechanism is below a pre-defined release threshold. The pre-defined release threshold should be equal or near to zero such that release mechanism will only open one of the first crane (e.g., the vessel crane 36) or the second crane (e.g., the nacelle crane 24) is substantially load free.

[0043] With continued reference to Figs. 3 and 4, transitioning support of the wind turbine component 26 from the first crane (e.g., the vessel crane 36) to the second crane (e.g., the nacelle crane 24) includes moving the first and second crane interfaces 44, 46 relative to the yoke frame 40 while transitioning support of the wind turbine component 26 from the first crane (e.g., the vessel crane 36) to the second crane (e.g., the nacelle crane 24) and while the wind turbine component 26 is suspended in the air. In other words, when transitioning support, the load carried by the first crane (e.g., the vessel crane 36) is reduced and the load carried by the second crane (e.g., the nacelle crane 24) is increased in coordination with movement of the first crane interface 44 from the first position to the second position and the second crane interface 46 from the third position to the fourth position. During the transition of support of the wind turbine component 26 from the first crane (e.g., the vessel crane 36) to the second crane (e.g., the nacelle crane 24), the lifting yoke 38 is maintained in a substantially level orientation. As noted above, in the event that the lifting yoke 38 is not in a substantially level orientation, the inclination warning and protection system 52 may provide a warning and further may prevent the transition if the inclination (e.g., angle) of the lifting yoke 38 exceeds a predetermined threshold — which may be 5°, 10°, 15°, or 20°, for example. Referring now to Figs. 5 and 6, the figures show an alternative embodiment of the lifting yoke 38. Where the wind turbine component 26 in Figs. 3 and 4 is attached to the lifting yoke 38 by rigging 54 (via the load plate 42), the lifting yoke 38 depicted in Figs. 5 and 6 secures the wind turbine component 26 directly to the yoke frame 40 by a pair of load plates 42 (i.e. , without the use of rigging 54, as in Figs. 3 and 4). Such an embodiment of the lifting yoke 38 advantageously further reduces the total height of the lifting yoke 38 with the wind turbine component 26 attached. As a result, less of the lifting height of the vessel crane 36 and / or nacelle crane 24 is used (or wasted) when transporting the wind turbine component 26 with this embodiment of the lifting yoke 38.

[0044] While the present invention has been illustrated by the description of various embodiments and while these embodiments have been described in some detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the invention to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept. Various features of the invention may be used alone or in any combination depending on the needs and preferences of the user.

Claims

What is claimed is:1 . A method for handling a wind turbine component (26), comprising: providing a lifting yoke (38) having a yoke frame (40) configured to be connected to the wind turbine component (26); connecting the yoke frame (40) to the wind turbine component (26); providing a first crane (24, 36); attaching the first crane (24, 36) to a first crane interface (44, 46) on the lifting yoke (38); supporting the wind turbine component (26) with the first crane (24, 36) so that the wind turbine component (26) is suspended in an air and substantially an entire weight of the wind turbine component (26) is being supported by the first crane (24, 36); providing a second crane (36, 24); attaching the second crane (36, 24) to a second crane interface (46, 44) on the lifting yoke (38); and transitioning support of the wind turbine component (26) from the first crane (24, 36) to the second crane (36, 24) while the wind turbine component (26) is suspended in the air such that substantially the entire weight of the wind turbine component (26) is supported by the second crane (36, 24), wherein transitioning support of the wind turbine component (26) from the first crane (24, 36) to the second crane (36, 24) includes moving the first crane interface (44, 46) and the second crane interface (46, 44) relative to the yoke frame (40) while transitioning support of the wind turbine component (26) from the first crane (24, 36) to the second crane (36, 24).

2. The method of claim 1 , wherein transitioning support of the wind turbine component (26) from the first crane (24, 36) to the second crane (36, 24) further comprises maintaining a substantially level orientation of the lifting yoke (38) while transitioning support of the wind turbine component (26) from the first crane (24, 36) to the second crane (36, 24).

3. The method of claim 1 or 2, wherein moving the first crane interface (44, 46) and second crane interface (46, 44) relative to the yoke frame (40) further comprisesmoving the first crane interface (44, 46) from a first position to a second position and moving the second crane interface (46, 44) from a third position to a fourth position.

4. The method of claim 3, wherein the wind turbine component (26) includes a center of gravity (CG), wherein when the first crane interface (44, 46) is in the first position, the first crane interface (44, 46) is substantially vertically aligned with the center of gravity (CG) of the wind turbine component (26), and wherein when the second crane interface (46, 44) is in the fourth position, the second crane interface (46, 44) is substantially vertically aligned with the center of gravity (CG) of the wind turbine component (26).

5. The method of claim 3 or 4, further comprising reducing a load carried by the first crane (24, 36) and increasing the load carried by the second crane (36, 24) in coordination with movement of the first crane interface (44, 46) from the first position to the second position and the second crane interface (46, 44) from the third position to the fourth position.

6. The method of any of the preceding claims, wherein moving the first crane interface (44, 46) relative to the yoke frame (40) further comprises energizing at least one actuator (50) to move the first crane interface (44, 46), and wherein moving the second crane interface (46, 44) relative to the yoke frame (40) further comprises energizing the at least one actuator (50) to move the second crane interface (46, 44).

7. The method of claim 6, wherein the lifting yoke (38) includes a slide mechanism (48) to which the first crane interface (44) and the second crane interface (46) are connected, and wherein moving the first crane interface (44) and the second crane interface (46) comprises energizing the at least one actuator (50) to move the slide mechanism (48) between a first slide location and a second slide location.

8. The method of claim 6, wherein the at least one actuator (50) includes a first actuator (50) operatively connected to the first crane interface (44, 46) and a second actuator (50) operatively connected to the second crane interface (46, 44), and wherein:moving the first crane interface (44, 46) relative to the yoke frame (40) further comprises energizing the first actuator (50); and moving the second crane interface (46, 44) relative to the yoke frame (40) further comprises energizing the second actuator (50).

9. The method of any of claims 6-8, wherein energizing the at least one actuator (50) includes remotely energizing the at least one actuator (50).

10. The method of any of the preceding claims, wherein attaching the second crane (36, 24) to the second crane interface (46, 44) further comprises attaching the second crane (36, 24) to the second crane interface (46, 44) while the wind turbine component (26) is suspended in the air.11 . The method of any of the preceding claims, further comprising detaching the first crane (24, 36) from the first crane interface (44, 46) after the second crane (36, 24) is attached to the second crane interface (46, 44) and substantially the entire weight of the wind turbine component (26) is supported by the second crane (36, 24).

12. The method of any of claims 2-11 , further comprising providing a warning when an inclination of the lifting yoke (38) exceeds a predetermined threshold while transitioning the support of the wind turbine component (26) from the first crane (24, 36) to the second crane (36, 24).

13. The method of any of the preceding claims, wherein the handling of the wind turbine component (26) is a lifting process of the wind turbine component (26) to a top of a wind turbine tower (12), and wherein: providing the first crane (24, 36) includes providing a ship crane (36); and providing the second crane (36, 24) includes providing a nacelle crane (24).

14. The method of any of claims 1 -12, wherein the handling of the wind turbine component (26) is a lowering process of the wind turbine component (26) from a top of a wind turbine tower (12), and wherein: providing the first crane (24, 36) includes providing a nacelle crane (24); and providing the second crane (36, 24) includes providing a ship crane (36).

15. A lifting yoke (38) for handling a wind turbine component (26) using a first crane (24, 36) and a second crane (36, 24), the lifting yoke (38) comprising: a yoke frame (40) configured to be connected to the wind turbine component (26); a first crane interface (44, 46) movably connected to the yoke frame (40) and configured to be connected to the first crane (24, 36); a second crane interface (46, 44) movably connected to the yoke frame (40), spaced from the first crane interface (44, 46), and configured to be connected to the second crane (36, 24); and at least one actuator (50) for moving the first crane interface (44, 46) between a first position and a second position and for moving the second crane interface (46, 44) between a third position and a fourth position, wherein in the first position the first crane interface (44, 46) is configured to be vertically aligned with a center of gravity (CG) of the wind turbine component (26), and wherein in the fourth position the second crane (36, 24) interface is configured to be vertically aligned with the center of gravity (CG) of the wind turbine component (26).

16. The lifting yoke (38) of claim 15, wherein the first crane interface (44, 46) is connected to the second crane interface (46, 44) such that movement of one of the first crane interface (44, 46) or the second crane interface (46, 44) causes movement of the other of the first crane interface (44, 46) or the second crane interface (46, 44).

17. The lifting yoke (38) of claim 15, wherein the first crane interface (44, 46) and the second crane interface (46, 44) are moveable independently of each other, and wherein the at least one actuator (50) includes a first actuator (50) connected to the first crane interface (44, 46) and a second actuator (50) connected to the second crane interface (46, 44).

18. The lifting yoke (38) of any of claims 15-17, wherein the lifting yoke (38) further comprises an inclination warning system (52) configured to provide a warning when an inclination of the lifting yoke (38) exceeds a predetermined threshold while transitioning support of the wind turbine component (26) from the first crane (24, 36) to the second crane (36, 24).

Images