Methods for extracting transformers of nacelle of wind turbine

Abstract

To provide methods for extracting transformers from nacelles of wind turbines.MEANS FOR SOLVING THE PROBLEM: The methods include moving a cart along a guide system, where the cart carries the transformer, and where the guide system comprises a first guide part arranged inside a nacelle and a second guide part extending through an opening in the nacelle beyond a first end of the nacelle. The methods further include moving the transformer along the second guide part to arrange the transformer outside of the nacelle. Nacelles and wind turbines suitable for such methods are also disclosed.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a method for extracting electrical components from a nacelle of a wind turbine, and more particularly to a method for extracting transformers from a nacelle of a wind turbine. [Background technology]

[0002] Wind turbines today are commonly used to provide electricity to the power grid. This type of wind turbine typically includes a tower and a rotor disposed on the tower. The rotor typically includes a hub and a number of blades, which rotate under the influence of wind on the blades. This rotation generates a torque that is typically transferred via the rotor shaft to a generator, either directly ("direct drive" or "gearless") or using a gearbox. The generator then generates electricity that can be provided to the electrical grid.

[0003] Wind turbines have evolved rapidly over the last few decades, with a clear trend towards larger sizes. The power generated by a wind turbine is proportional to the rotor swept area, and therefore to the square of the blade length. Therefore, taller towers and longer blades have been used to extract more energy from the wind and obtain higher power output. Over the years, the increase in size has led to a significant increase in the loads acting on wind turbine components, posing new challenges to a wide range of disciplines, including mechanical, electrical, material and civil engineering.

[0004] The electricity generated by the wind turbine generator is conditioned through various electrical components such as transformers and power converters. The turbine's transformer increases the voltage amplitude of the electricity and the conditioned electricity is fed into the power grid.

[0005] These electrical components have typically been located at the base of the wind turbine tower, but are becoming more commonplace in the nacelle of the wind turbine.

[0006] Transformers and converters are relatively large and heavy (they can weigh around 10-11 tons). If a component such as a transformer is damaged, it takes a lot of time and effort to replace it. Replacing such heavy components is a challenge, especially when they are installed in the wind turbine nacelle, which is high above the ground.

[0007] For transformers installed in a nacelle, it is known to use a lifting device to remove the transformer from the top of the nacelle. In this case, a lifting line from a crane is connected to the transformer, which is then lifted through an opening in the top of the nacelle and removed. During removal, the lifting action can cause vibrations in the transformer, which can then hit elements in the nacelle and be damaged. This method is therefore very delicate and time-consuming.

[0008] It is also known to remove the transformer from the bottom of the nacelle, for example through a hatch. These methods require the use of a special crane, which must be placed inside the nacelle.

[0009] The present disclosure provides methods and apparatus that at least partially overcome some of the aforementioned shortcomings. Summary of the Invention

[0010] In one aspect of the disclosure, a method of removing a transformer from a nacelle of a wind turbine is provided. The method includes moving a cart along a guide system, the cart carrying the transformer, the guide system including a first guide portion disposed inside the nacelle and a second guide portion extending through an opening in the nacelle and beyond a first end of the nacelle. The method further includes moving the transformer along the second guide portion and disposing the transformer outside the nacelle.

[0011] This aspect simplifies the extraction of the transformer from the nacelle of the wind turbine. The transformer can be extracted without the use of complex or heavy tools. The extraction time can also be significantly reduced. Furthermore, the transformer is constantly under controlled motion during the extraction process, which eliminates or reduces the risk of damage to components inside the nacelle due to vibrations of the transformer.

[0012] In another aspect of the disclosure, a nacelle for a wind turbine is provided. The nacelle includes a transformer. The nacelle further includes a guide system configured to guide a cart. The guide system includes a first guide part disposed within the nacelle and a second guide part configured to extend beyond a first end of the nacelle through an opening, and the cart is configured to carry the transformer.

[0013] In a further aspect, a wind turbine is provided. The wind turbine comprises a tower, a nacelle, and one or more blades rotatably supported on the nacelle via a hub. The nacelle comprises a transformer. The nacelle further comprises a guide system configured to guide a cart. The guide system comprises a first guide portion disposed inside the nacelle and a second guide portion, the second guide portion configured to extend beyond a first end of the nacelle through an opening, and the cart is configured to carry the transformer.

[0014] Additional objects, advantages and features of the embodiments of the present disclosure will become apparent to those skilled in the art upon examination of the specification or may be learned by practice. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic perspective view of an example wind turbine. [Diagram 2] 1 shows an example of a wind turbine hub and nacelle. [Diagram 3]1 is a flow chart illustrating an example of a method for extracting a transformer from a nacelle of a wind turbine. [Figure 4] 1 illustrates a schematic diagram of an example nacelle according to the present disclosure. [Diagram 5] 1 illustrates a schematic diagram of an example of a portion of a guide system according to the present disclosure; [Figure 6] 1 illustrates a schematic diagram of an example nacelle according to the present disclosure. [Figure 7] 1 is a flow chart illustrating an example of a method for installing a transformer in a nacelle of a wind turbine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Reference will now be made in detail to the embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of illustration and not by way of limitation. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the teachings. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still further embodiments. Thus, the present disclosure is intended to cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0017] FIG. 1 is a perspective view of an example of a wind turbine 10. In this example, the wind turbine 10 is a horizontal axis wind turbine. Alternatively, the wind turbine 10 may be a vertical axis wind turbine. In this example, the wind turbine 10 includes a tower 15 extending from a support system 14 on a ground 12, a nacelle 16 attached to the tower 15, and a rotor 18 coupled to the nacelle 16. The rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to the hub 20 and extending outwardly from the hub 20. In this example, the rotor 18 has three rotor blades 22. In alternative embodiments, the rotor 18 includes more or less than three rotor blades 22. The tower 15 may be fabricated from tubular steel to define a cavity (not shown in FIG. 1) between the support system 14 and the nacelle 16. In alternative embodiments, the tower 15 may be any suitable type of tower having any suitable height. According to an alternative, the tower may be a hybrid tower including a concrete portion and a steel tubular portion. It may also be a partial or complete lattice tower.

[0018] The rotor blades 22 are spaced relative to the hub 20 to rotate the rotor 18 and convert kinetic energy from the wind into usable mechanical energy, and therefore electrical energy. The rotor blades 22 are mated to the hub 20 by coupling blade root portions 24 to the hub 20 at a number of load transfer regions 26. The load transfer regions 26 may include hub load transfer regions and blade load transfer regions (both not shown in FIG. 1 ). Loads induced in the rotor blades 22 are transferred to the hub 20 through the load transfer regions 26.

[0019] In this example, the rotor blades 22 may have a length ranging from about 15 m (meters) to about 90 m or more. The rotor blades 22 may have any suitable length that enables the wind turbine 10 to function as described herein. For example, non-limiting examples of blade lengths include lengths of 20 m or less, 37 m, 48.7 m, 50.2 m, 52.2 m, or more than 91 m. When wind strikes the rotor blades 22 from a wind direction 28, the rotor 18 rotates about a rotor axis 30. As the rotor blades 22 rotate and experience centrifugal forces, the rotor blades 22 also experience various forces and moments. As such, the rotor blades 22 may deflect and / or rotate from a neutral, or non-deflected, position to a deflected position.

[0020] Additionally, the pitch angle of the rotor blades 22, i.e., the angle determining the orientation of the rotor blades 22 relative to the wind direction, can be varied by the pitch system 32 to control the load and power generated by the wind turbine 10 by adjusting the angular position of at least one rotor blade 22 relative to the wind vector. A pitch axis 34 of the rotor blades 22 is shown. During operation of the wind turbine 10, the pitch system 32 can, among other things, vary the pitch angle of the rotor blades 22 to reduce the angle of attack of (some of) the rotor blades, thereby facilitating a reduction in rotational speed and / or facilitating a stall of the rotor 18.

[0021] In this embodiment, the blade pitch of each rotor blade 22 is individually controlled by the wind turbine controller 36 or pitch control system 80. Alternatively, the blade pitch of all rotor blades 22 may be controlled simultaneously by a control system.

[0022] Further, in this example, as wind direction 28 changes, nacelle 16 may be rotated about yaw axis 38 to position rotor blades 22 relative to wind direction 28 .

[0023] In this example, the wind turbine controller 36 is shown as centralized in the nacelle 16, however, the wind turbine controller 36 may be a distributed system throughout the wind turbine 10, on the support system 14, in the wind farm, and / or at a remote control center. The wind turbine controller 36 includes a processor 40 configured to perform the methods and / or steps described herein. Additionally, many of the other components described herein include a processor.

[0024] As used herein, the term "processor" is not limited to integrated circuits referred to in the art as computers, but refers broadly to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application specific, integrated circuits, and other programmable circuits, and these terms are used interchangeably herein. It should be understood that a processor and / or control system may also include memory, input channels, and / or output channels.

[0025] FIG. 2 is an enlarged cross-sectional view of a portion of the wind turbine 10. In this example, the wind turbine 10 includes a nacelle 16 and a rotor 18 rotatably coupled to the nacelle 16. More specifically, a hub 20 of the rotor 18 is rotatably coupled to a generator 42 disposed within the nacelle 16 by a main shaft 44, a gearbox 46, a high-speed shaft 48, and a coupling 50. In the example, the main shaft 44 is disposed at least partially coaxially with a longitudinal axis (not shown) of the nacelle 16. Rotation of the main shaft 44 drives a gearbox 46, which drives the high-speed shaft 48 by converting the relatively slow rotational motion of the rotor 18 and main shaft 44 into a relatively fast rotational motion of the high-speed shaft 48. The latter is connected, with the aid of the coupling 50, to a generator 42 for generating electrical energy. Further, a transformer 90 and / or appropriate electronics, switches, and / or inverters may be disposed within the nacelle 16 to convert the electrical energy generated by the generator 42 having a voltage of 400V-1000V into electrical energy having a moderate voltage, for example 10-35 KV. The electrical energy is conducted from the nacelle 16 to the tower 15 via a power cable.

[0026] The gearbox 46, the generator 42 and the transformer 90 may be supported by a main support structural frame of the nacelle 16, optionally embodied as a main frame 52. The gearbox 46 may include a gearbox housing coupled to the main frame 52 by one or more torque arms 103. In an embodiment, the nacelle 16 also includes a main forward support bearing 60 and a main aft support bearing 62. Additionally, the generator 42 may be mounted to the main frame 52 by a decoupling support means 54, particularly to prevent vibrations of the generator 42 from being introduced into the main frame 52 and thereby causing a source of noise emissions.

[0027] Optionally, main frame 52 is configured to carry the weight of rotor 18 and nacelle 16 components, as well as the overall loads caused by wind and rotational loads, and to introduce these loads into tower 15 of wind turbine 10. The rotor shaft 44, generator 42, gearbox 46, high speed shaft 48, coupling 50, and main frame 52, and any associated fastening, supporting, and / or fastening devices, including, but not limited to, forward support bearing 60 and aft support bearing 62, may be referred to as a drive train 64.

[0028] In some embodiments, the wind turbine may be a direct drive wind turbine without a gearbox 46. The generator 42 operates at the same rotational speed as the rotor 18 of the direct drive wind turbine and therefore typically has a much larger diameter than the generator used in a wind turbine with a gearbox 46 to provide the same amount of power as a wind turbine with a gearbox 46.

[0029] The nacelle 16 may also include a yaw drive mechanism 56 that is used to rotate the nacelle 16, and thereby the rotor 18, about the yaw axis 38 to control the approach or approach of the rotor blades 22 relative to the wind direction 28.

[0030] To properly position the nacelle 16 relative to the wind direction 28, the nacelle 16 may also include at least one meteorological measurement system 58 including a wind vane and anemometer. The meteorological measurement system 58 may provide information including the wind direction 28 and / or wind speed to the wind turbine controller 36. In this embodiment, the pitch system 32 is at least partially disposed within the hub 20 as a pitch assembly 66. The pitch assembly 66 includes one or more pitch drive systems 68 and at least one sensor 70. Each pitch drive system 68 is coupled to a respective rotor blade 22 (shown in FIG. 1 ) for modulating the pitch angle of the rotor blade 22 along the pitch axis 34. Only one of the three pitch drive systems 68 is shown in FIG. 2 .

[0031] In this embodiment, the pitch assembly 66 includes at least one pitch bearing 72 coupled to the hub 20 and each rotor blade 22 (shown in FIG. 1 ) to rotate each rotor blade 22 about the pitch axis 34. The pitch drive system 68 includes a pitch drive motor 74, a pitch drive gearbox 76, and a pitch drive pinion 78. The pitch drive motor 74 is coupled to the pitch drive gearbox 76 such that the pitch drive motor 74 provides a mechanical force to the pitch drive gearbox 76. The pitch drive gearbox 76 is coupled to the pitch drive pinion 78 such that the pitch drive pinion 78 is rotated by the pitch drive gearbox 76. The pitch bearing 72 is coupled to the pitch drive pinion 78 such that rotation of the pitch drive pinion 78 causes rotation of the pitch bearing 72.

[0032] The pitch drive system 68 is coupled to the wind turbine controller 36 for adjusting the pitch angle of the rotor blades 22 in response to one or more signals from the wind turbine controller 36. In this example, the pitch drive motor 74 is any suitable motor driven by an electric power and / or hydraulic system that enables the pitch assembly 66 to function as described herein. Alternatively, the pitch assembly 66 may include any suitable structure, configuration, arrangement, and / or components, such as, but not limited to, hydraulic cylinders, springs, and / or servo mechanisms. In certain embodiments, the pitch drive motor 74 is driven by the rotational inertia of the hub 20 and / or energy extracted from a stored energy source (not shown) that provides energy to components of the wind turbine 10.

[0033] The pitch assembly 66 may also include one or more pitch control systems 80 for controlling the pitch drive systems 68 in accordance with control signals from the wind turbine controller 36 in case of certain preferred conditions and / or upon overspeed of the rotor 18. In an example embodiment, the pitch assembly 66 includes at least one pitch control system 80 communicatively coupled to each pitch drive system 68 for controlling the pitch drive systems 68 independently from the wind turbine controller 36. In an example embodiment, the pitch control system 80 is coupled to the pitch drive systems 68 and to the sensors 70. During normal operation of the wind turbine 10, the wind turbine controller 36 may control the pitch drive systems 68 to adjust the pitch angle of the rotor blades 22.

[0034] According to one embodiment, a generator 84, including, for example, batteries and electric capacitors, is disposed at or within the hub 20 and is coupled to the sensors 70, pitch control system 80, and pitch drive system 68 to provide a source of electrical power to these components. In this example, the generator 84 provides a continuous source of electrical power to the pitch assembly 66 during operation of the wind turbine 10. In an alternative embodiment, the generator 84 provides electrical power to the pitch assembly 66 only during a power loss event of the wind turbine 10. A power loss event may include a loss or dip in the electrical grid, a malfunction of the electrical system of the wind turbine 10, and / or a failure of the wind turbine controller 36. During a power loss event, the generator 84 operates to provide electrical power to the pitch assembly 66 such that the pitch assembly 66 can operate during the power loss event.

[0035] In this example, pitch drive system 68, sensor 70, pitch control system 80, cables, and generator 84 are each disposed within a cavity 86 defined by an inner surface 88 of hub 20. In alternative embodiments, the components may be positioned relative to an outer roof surface of hub 20 and coupled directly or indirectly to the outer roof surface.

[0036] In one aspect of the present invention, a method 300 for extracting a transformer from a nacelle of a wind turbine is disclosed. FIG.

[0037] The method 300 includes, at step 302, moving a cart along a guide system, the cart carrying a transformer, the guide system including a first guide portion disposed inside the nacelle and a second guide portion extending through an opening in the nacelle and beyond a first end of the nacelle. The method further includes, at step 304, moving the transformer along the second guide portion to position the transformer outside the nacelle.

[0038] This method can provide a method of extracting the transformer from the nacelle without the need for complex and heavy tooling. Extraction of the transformer is relatively fast and simplified.

[0039] Various embodiments of a method for extracting a transformer from a nacelle of a wind turbine are shown diagrammatically in Figs.

[0040] 4 shows a schematic diagram of an example of a wind turbine nacelle 16 including a transformer 90 and a guide system 100. The guide system 100 is configured to guide a cart. The guide system 100 includes a first guide portion 111 disposed inside the nacelle 16 and a second guide portion 112. The second guide portion 112 of the guide system is configured to extend beyond the first end 17 of the nacelle through an opening 19, and the cart is configured to carry the transformer 90.

[0041] Throughout this disclosure, a cart can be considered as any type of transport element suitable for transporting the transformer and displacing it along a guide, for example through wheels or rollers, or by sliding on skates or pads.

[0042] The method may include opening or removing a cover to form an opening 19 at a first end 17 of the nacelle. The nacelle may include a first end 17 that includes an openable and / or removable cover.

[0043] As shown in Figure 4, the first end 17 of the nacelle may comprise the aft end of the nacelle. Depending on the location of the transformer within the nacelle and the distribution of other elements within the nacelle, the opening 19 may be located at a particular location on the exterior wall of the nacelle. In other examples, the first end 17 of the nacelle may comprise one of the lateral ends of the nacelle.

[0044] The opening 19 need only be large enough to allow passage of the transformer 90, the cart and the guide system 100. The cover can be opened and removed manually or automatically.

[0045] The method may further include connecting a transformer 90 to the cart 130 prior to moving the cart 130 along the guide system 100 .

[0046] As shown in FIG. 4, the transformer 90 may be suspended from a cart and moved along a guide system 100. Further, the cart may move the transformer 90 through an opening 19 from a first location to a second location. In some examples, the first location may be a location inside the nacelle and the second location may be a location outside the nacelle. In other examples, the transformer may be moved from outside the nacelle to inside the nacelle.

[0047] In some examples, the method may include moving elements within the nacelle out of the trajectory of the transformer 90 within the nacelle. Elements within the nacelle 16 located between the opening 19 and the transformer 90 may be moved prior to moving the cart carrying the transformer. These elements may be moved within the nacelle 16 out of the trajectory of the transformer 90. The trajectory may be considered as a path of travel that the transformer 90 may follow as it is moved along the guide system 100.

[0048] An example of a portion of a guide system 100 configured to guide a cart 130 for transporting a transformer 90 is shown in FIG.

[0049] As shown generally in FIG. 5, the guide system 100 may include a longitudinal rail 110, and the cart 130 may include one or more rollers or sliding pads 120 configured to move along the longitudinal rail 110.

[0050] In some examples, the longitudinal rails 110 may include beams, such as an I-beam. The longitudinal rails 110 may be substantially straight and may be substantially parallel to the floor of the nacelle. The longitudinal rails 110 may be configured to bear the weight of the transformer 90. The longitudinal rails 110 may be made of steel.

[0051] The cart 130 may be configured to displace (move) along the longitudinal rails 110 and to transport the transformer 90. In the example shown in Fig. 5, the cart is guided along the longitudinal rails 110 by two rollers. The cart 130 may be moved along the longitudinal rails 110 by means of, for example, an electric motor.

[0052] Additionally, the guide system 100 may include fixation or locking elements 140 connected to the cart 130. The fixation elements 140 may have an open or "unlocked" configuration and a closed or "locked" configuration. In the open configuration, the fixation elements 140 may allow movement of the cart 130 along the longitudinal rails 110. In the closed configuration, the fixation elements 140 may connect to the longitudinal rails 110 in addition to the cart 130, thereby preventing the cart 130 from moving along the longitudinal rails 110. The fixation elements 140 may ensure that the cart 130 moves along the longitudinal rails 110 only when desired.

[0053] In some embodiments, during normal operation of the wind turbine, the transformer 90 may be suspended from the cart 130. In some embodiments, both ends of the cart 130 may be resiliently connected to the guide system 100, such as the longitudinal rails 110, to form a tuned mass damper (not shown). By using the transformer for damping, the use of an additional mass damper may be avoided, reducing the overall weight of the nacelle.

[0054] In other embodiments, the transformer 90 may be lifted off the nacelle floor prior to removal from the nacelle. In some embodiments, the guide system 100 may include a hoist (not shown) configured to connect with the transformer 90. The transformer 90 is lifted off the nacelle floor with a hoist, for example one or more chain hoists, and connected to the cart 130. In some examples, the hoist may be part of the cart 130.

[0055] In some examples, the transformer 90 may be connected to the cart 130 through one or more silent blocks 135. The silent blocks 135 may be made from a flexible or elastomeric material and may be configured to absorb vibrations and dampen any energy that may be transmitted through the silent blocks. As shown in FIG. 5, the transformer 90 may be connected to the cart 130 through two silent blocks 135.

[0056] Returning to FIG. 4, the longitudinal rail of the guide system 100 can include a first guide portion 111 and a second guide portion 112 .

[0057] The first guide portion 111 of the longitudinal rail may be located inside the nacelle 16. In the nacelle, the first guide portion 111 of the longitudinal rail may be located above the transformer 90, allowing a connection between the transformer 90 and a cart 130 configured to displace along a guide system.

[0058] By locating the first guide portion 111 of the longitudinal rail inside the nacelle, part of the guide system can be kept permanently available and the process of moving the transformer can be simplified.

[0059] In some examples, the first guide portion 111 of the longitudinal rail may be attached to an inner wall of the nacelle. In other examples, the first guide portion 111 of the longitudinal rail may be attached to a wall that is parallel to the floor of the nacelle and defines a ceiling above the transformer 90. The first guide portion 111 of the longitudinal rail may extend towards the first end 17 of the nacelle, i.e., towards the opening 19.

[0060] 4, the second guide portion 112 of the guide system extends beyond the first end 17 of the nacelle through the opening 19 so that the transformer 90 can be moved from inside the nacelle to outside the nacelle, i.e., in this example, the nacelle is moved from the first guide portion 111 of the guide system to the second guide portion 112 of the guide system. In other examples, when installing or reinstalling the transformer, the transformer 90 can be moved from the second guide portion 112 of the guide system to the first guide portion 111 of the guide system.

[0061] In some examples, the guide system 100 may be a telescopic guide system, and the second guide portion 112 of the longitudinal rail may be movable relative to the first guide portion 111 of the longitudinal rail along the longitudinal axis.

[0062] In such an embodiment, the telescoping guide system may allow the second guide portion 112 of the longitudinal rail to be in a retracted position or an extended position. The retracted position may include a position where the second guide portion 112 of the longitudinal rail is located inside the nacelle. In the extended position, the second guide portion 112 of the longitudinal rail may extend through the opening 19 and beyond the first end 17 of the nacelle.

[0063] The telescoping guide system may provide a guide system that is permanently installed within the nacelle, which may simplify the process of removing and / or installing the transformer, since no additional tools or equipment is required to prepare the guide system for moving the transformer, for example, from a first position inside the nacelle to a second position outside the nacelle.

[0064] During normal operation of the nacelle, the second guide portion 112 of the longitudinal rail may be in a retracted position. When the transformer needs to be removed from (or introduced into) the nacelle 16, a cover at the first end 17 of the nacelle may be opened and / or removed to form an opening 19. Once the opening 19 is formed, the second portion 112 of the longitudinal rail may be moved to its extended position. In this example, the cart 130 may be configured to move along the second guide portion 112 of the longitudinal rail once in the extended position.

[0065] In some embodiments, the telescopic guide system may be connected to electrical means. In other embodiments, the second guide portion 112 of the longitudinal rail may be manually moved to the extended or retracted position.

[0066] In a further example, the method may include releasably attaching the second guide portion 112 to the first guide portion 111. In some examples, the method may include using a crane to hoist the second guide portion 112 towards the nacelle. A lifting device such as a crane can carry the second guide portion 112 of the longitudinal rail and position it adjacent to the first guide portion 111 of the longitudinal rail through the opening 19 of the nacelle. The first guide portion 111 and the second guide portion 112 can then be attached together. For example, a specialized worker can attach both parts together with bolts or other suitable fasteners. The second guide portion 112 of the longitudinal rail does not need to be permanently located in the nacelle, which can avoid additional weight.

[0067] In another example, the second guide portion 112 is lifted by an internal crane of the nacelle.

[0068] Figure 6 shows a schematic representation of the nacelle 16 comprising the guidance system 100 according to the embodiment shown in Figures 4 and 5. A second guide portion 112 of the guidance system extends through an opening in the nacelle beyond the first end of the nacelle and carries the transformer 90.

[0069] In some instances, the transformer 90 is a damaged transformer that is removed from the nacelle.

[0070] The method of removing the transformer from the nacelle may further include moving the transformer 90 out of the nacelle 16 and then picking up the transformer 90 with a crane.

[0071] In some embodiments, a lifting device (not shown) can be used to lift the damaged transformer 90 from the second guide portion 112 of the longitudinal rail. The lifting device is connected to the transformer 90, and the transformer 90 is released from the cart 130.

[0072] In some embodiments, lifting the transformer 90 with a crane includes connecting hoisting equipment to the second guide portion 112 of the guide system. The second guide portion 112 is then disconnected from the first guide portion, for example by a specialized operator, and the transformer 90, the second guide portion 112 and the cart 130 are all lifted with the crane. The second guide portion may include suitable locking elements or stops to hold the transformer in a fixed position relative to the second guide portion. The extraction process may be safer, since a specialized operator can pick up the transformer without accessing the exterior of the nacelle.

[0073] In other embodiments, a hoisting device may be used to mount the transformer 90, e.g. a new transformer, on a cart 130 placed on the second guide portion 112 of the longitudinal rail. The cart 130 loaded with the new transformer 90 may move along the second guide portion 112 of the longitudinal rail and the first guide portion 111 of the longitudinal rail. In some embodiments, in a further step, the transformer 90 is lowered into position in the nacelle, e.g. through a hoist of the guide system. In other embodiments, both ends of the cart 130 may be elastically coupled to the longitudinal rail 110 to form a tuned mass damper.

[0074] In a further aspect of the disclosure, a wind turbine 10 is provided. The wind turbine 10 comprises a tower 15, a nacelle 16, and one or more blades 22 rotatably supported from the nacelle 16 via a hub 20. The nacelle 16 comprises a transformer 90 and a guide system 100 configured to carry a cart 130. The guide system 100 includes a first guide portion 111 disposed within the nacelle and a second guide portion 112. The second guide portion 112 is configured to extend beyond the first end 17 of the nacelle through an opening 19, and the cart 130 is configured to carry the transformer 90.

[0075] In yet another aspect of the present disclosure, a method 700 for installing a transformer in a nacelle of a wind turbine is provided. FIG.

[0076] The method includes, at step 702, moving a cart along a guide system, the cart carrying a transformer, the guide system including a first guide portion disposed within the nacelle and a second guide portion extending through an opening in the nacelle and beyond a first end of the nacelle. The method further includes, at step 704, moving the transformer along the first guide portion to position the transformer within the nacelle.

[0077] The aspects and descriptions relating to method 300 may be applied to method 700 in combination in reverse order.

[0078] This specification uses examples to disclose the teachings, including preferred embodiments, and to enable any person skilled in the art to practice the teachings, including making and using any devices or systems, and performing any methods incorporated therein. The patentable scope is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be included in the claims if they have structural elements that do not differ from the language of the claims, or if they include equivalent structural elements that do not differ substantially from the language of the claims. Aspects from the various embodiments described, and other known equivalents to each such aspect, may be mixed and matched by those skilled in the art to construct additional embodiments and techniques according to the principles of this application. When reference signs related to the drawings are placed in parentheses in the claims, they are merely intended to improve the clarity of the claims, and should not be construed as limiting the scope of the claims. [Explanation of symbols]

[0079] 10: Wind turbine 12: Ground 14: Support system 15: Tower 16: Nacelle 17: First end 18: Rotor 19: Opening 20: Hub 22: Rotor blades 24: Blade root area 26: Load transfer area 28: Wind direction 30: Rotor shaft 32: Pitch system 34: Pitch axis 36: Wind turbine controller 38: Yaw axis 42: Generator 44: Main shaft 46: Gearbox 48: High speed shaft 50: Coupling 51: Shaft sensor 52: Main frame 53: Generator sensor 54: Decoupling support means 56: Yaw drive mechanism 58: Meteorological measurement system 60: Main forward support bearing 62: Main aft support bearing 64: Drive train 66: Pitch assembly 68: Pitch drive system 70: Sensor 72: Pitch bearing 74: Pitch drive motor 76: Pitch drive gearbox 78: Pitch drive pinion 80: Pitch control system 84: Power source / generator 86: Cavity 88: Inner surface 90: Transformer 100: Guide system 110: Longitudinal rail 111: First guide section 112: Second guide section 120: Roller / slide pad 130: Cart 135: Silencer block 140: Fixing element / locking element

Claims

1. A method for extracting a transformer (90) from a nacelle (16) of a wind turbine, comprising the steps of: moving a cart (130) carrying the transformer (90) along a guide system (100), the guide system (100) comprising a first guide portion (111) disposed inside the nacelle (16) and a second guide portion (112) extending through an opening (19) in the nacelle and beyond a first end (17) of the nacelle; moving the transformer (90) along the second guide portion (112) to position the transformer (90) outside the nacelle (16); A method comprising:

2. The method of claim 1, further comprising the step of connecting the transformer (90) to the cart (130) prior to moving the cart (130) along the guide system (100).

3. The method of claim 2, wherein the step of connecting the transformer (90) to the cart (130) comprises the step of suspending the transformer (90) from the cart (130).

4. The method of claim 1, wherein the first end (17) of the nacelle is an aft end of the nacelle.

5. The method of claim 1, comprising the step of moving an element within the nacelle from a track of the transformer (90) within the nacelle.

6. 2. The method of claim 1, wherein the guide system (100) is a telescopic guide system, and the second guide part (112) is movable relative to the first guide part (111) along a longitudinal axis.

7. The method of claim 1, comprising attaching the second guide portion (112) to the first guide portion (111).

8. The method of claim 7, comprising hoisting the second guide portion (112) towards the nacelle (16) with a crane.

9. The method of claim 1 , wherein the guide system (100) further comprises a hoist, the method including the step of lifting the transformer (90) off a floor of the nacelle (16) with the hoist.

10. The method according to any one of claims 1 to 9, further comprising the step of lifting the transformer (90) with a crane after moving the transformer (90) outside the nacelle (16), optionally with the crane being lifted while attached to the second guide part.

11. A nacelle (16) for a wind turbine, comprising: A transformer (90); a guide system (100) configured to guide the cart (130); The guide system (100) comprises a first guide portion (111) arranged inside the nacelle (16) and a second guide portion (112); the second guide portion (112) is configured to extend beyond the first end (17) of the nacelle through an opening (19); The cart (130) is configured to carry the transformer (90). A nacelle (16).

12. 12. The nacelle (16) of claim 11, wherein the guide system (100) includes a longitudinal rail (110) and the cart (130) includes one or more rollers or slide pads (120) configured to move along the rail.

13. The nacelle (16) of claim 11, wherein both ends of the cart (130) are resiliently coupled to the guide system (100) to form a tuned mass damper.

14. 12. The nacelle (16) of claim 11, wherein the guide system (100) is a telescopic guide system, and the second guide portion (112) is movable relative to the first guide portion (111) of the longitudinal rail (110) along the longitudinal axis.

15. Tower (15) and A nacelle (16) according to any one of claims 11 to 14, one or more blades (22) rotatably supported on the nacelle (16) via a hub (20); A wind turbine (10).

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