Helicopter hoisting platform

Abstract

To provide a helicopter hoisting platform for a wind turbine nacelle cover.SOLUTION: The present invention discloses a helicopter hoisting platform for a wind turbine nacelle cover, the helicopter hoisting platform comprising a composite layer and a plurality of metal plates arranged on the outer surface of the composite layer, where the metal plates form a conductive network electrically connected to a ground connection.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to wind turbines, and more particularly to a lifting platform for a helicopter of a wind turbine. The present disclosure further relates to a nacelle cover assembly including a lifting platform for a helicopter and a method for providing the nacelle cover assembly.

Background Art

[0002] Wind turbines are widely used to convert wind energy into electricity. The generated electricity can be supplied to the power grid and electricity customers. A wind turbine generally includes a tower with a nacelle mounted on top. A rotor including a rotor hub and a plurality of blades is generally mounted on the nacelle and defines a rotatable coupling between the rotor and the nacelle. The plurality of blades use the aerodynamic force of the generated wind to generate a net positive torque on the rotating shaft, generating mechanical power, which is later generally converted into electricity by a generator housed in the wind turbine nacelle.

[0003] Wind turbines have evolved rapidly over the past few decades, and wind turbine components have been changed to withstand higher loads and adverse weather. A wind turbine nacelle houses a drive train and other up-tower components and protects them from external hazards such as precipitation, dust, UV radiation, and lightning strikes. Further, a wind turbine nacelle generally provides an inlet and an outlet for the air flow in the generator, withstands the wind force received by the blades and the heat generated by the drive train, and provides a working platform for qualified personnel. The nacelle is generally located on top of a yaw bearing that enables the nacelle to be rotated to keep the rotor aligned with the wind direction.

[0004] With the global growth of offshore wind energy, helicopters are becoming one of the most convenient modes of transport for reaching wind turbines, or more precisely, wind turbine nacelles. The long distances from land to offshore locations make helicopters a highly reliable, cost-effective, and safe solution for transport, rescue, and maintenance operations. Furthermore, using helicopters to reach offshore wind turbines can be a great relief when seas are rough. While ships may be unable to access offshore wind turbines, helicopters can carry out all the necessary transport, avoiding revenue losses.

[0005] Generally, helicopters cannot land on wind turbine nacelles; therefore, wind turbine nacelles are typically equipped with helicopter lifting platforms to facilitate the loading and unloading of personnel and / or goods. Thus, helicopters can hover over helicopter lifting platforms while lifting or lowering personnel or cargo via lifting cables.

[0006] In these situations, the helicopter may accumulate electric charge. Therefore, the static electricity in the helicopter must be safely discharged before any person makes contact between the helicopter and the wind turbine. To discharge, the helicopter lifting platform may be equipped with conductive material grounded via a support structure such as a nacelle bed frame, or any other structure that is also part of the electrical path to the ground. Thus, the helicopter crew can connect a conductive wire to the lifting hook, and the wire is long enough to reach the conductive material on the helicopter lifting platform and discharge the static electricity before any personnel on the wind turbine grasp the hook or before any personnel on the helicopter make contact with the ground. To discharge the static electricity to a safe level, it is further recommended to reduce the resistance of the electrical circuit from the static discharge wire contact to the ground to, for example, less than 15 kOhm.

[0007] Known methods for incorporating conductive materials on helicopter lifting platforms include applying a conductive cladding or coating to the outer surface of the platform, or providing conductive components on top of a helicopter lifting platform connected to the ground. However, prior art methods present several drawbacks that may impair the success of the helicopter's discharge operation.

[0008] On the other hand, methods involving surface treatments and / or surface covers such as conductive paints or cladding have limitations in terms of the electrical resistance range, providing high resistance in most cases and thus hindering helicopter discharge. Furthermore, surface treatments can be susceptible to scratches and other surface degradation, resulting in discontinuous conductive media and potentially creating isolated, non-conductive patches. This may suggest that conductive wires coming from the helicopter may come into contact with the helicopter lifting platform in a way that does not electrically couple to the ground, thus potentially preventing proper discharge. Moreover, conductive surface treatments may not provide a surface finish with sufficient grip for personnel to work safely in humid weather conditions. Offshore wind turbines inherently operate in very humid environments, so a non-slip surface finish may be important during lifting operations.

[0009] On the other hand, methods involving placing conductive plates or strips on top of helicopter lifting platforms result in an uneven surface finish, which poses a potential risk of slipping.

[0010] This disclosure provides a method and system for overcoming some of the aforementioned shortcomings, at least partially. [Overview of the project]

[0011] In one aspect of the present disclosure, a helicopter lifting platform for a wind turbine nacelle cover is provided. The helicopter lifting platform comprises a composite layer including at least an outer and inner surface. The helicopter lifting platform further comprises a plurality of metal plates disposed on the outer surface of the composite layer and spaced apart from each other. The plurality of metal plates form a conductive network electrically connected to a grounding connection located beneath the composite layer.

[0012] According to this embodiment, the helicopter lifting platform is provided with a platform that provides a safe and robust connection to the ground for the helicopter to discharge static electricity, due to the fact that the helicopter lifting platform comprises multiple metal plates arranged on the outer surface of a composite layer and spaced apart from one another. Furthermore, the helicopter lifting platform provides a reliable electrical connection to the ground for the helicopter's static discharge. By arranging the multiple metal plates at various intervals, the possibility of conductive wires not contacting the conductive network to the ground can be reduced. In addition, the presence of multiple individual metal plates allows for easy replacement of the metal plates in a very cost-effective, quick, and efficient manner when necessary.

[0013] Furthermore, according to this embodiment, the helicopter lifting platform can be assembled directly onto an existing nacelle cover, improving connectivity to the ground and enhancing its robustness.

[0014] In an additional embodiment, a method for providing a nacelle cover assembly is provided. The method includes the step of providing a nacelle cover assembly comprising a composite layer including at least an outer surface and an inner surface, the outer surface comprising one or more openings. The method further includes the steps of providing a plurality of metal plates on the outer surface of the composite layer, providing a grounding connection inside the nacelle cover assembly, and connecting the grounding connection to at least one of the metal plates. The method further includes providing a conductive network between the plurality of metal plates electrically connected to the grounding connection.

[0015] Further objects, advantages, and features of the embodiments of this disclosure will become apparent to those skilled in the art by examining the description or can be acquired through practice.

[0016] It should be noted that throughout this disclosure and with respect to the various embodiments disclosed herein, the term "metal plate" is used to refer to a conductive element having a thickness relatively thin relative to its length and width, and more specifically, a conductive element that may have a length much longer than its width. Furthermore, the term "conductive network" relating to metal plates means that the metal plates are interconnected with each other such that any point on a plurality of metal plates defines a conductive path to the ground. [Brief explanation of the drawing]

[0017] [Figure 1] This diagram schematically shows a perspective view of an example of a wind turbine. [Figure 2] This figure shows examples of wind turbine hubs and nacelles. [Figure 3] This figure schematically shows a perspective view of a wind turbine nacelle equipped with one embodiment of a helicopter lifting platform. [Figure 4] This figure schematically shows a perspective top view of another embodiment of a helicopter lifting platform. [Figure 5] This figure schematically shows a detailed perspective top view of the helicopter lifting platform of the nacelle cover, including a longitudinal cross-section passing through plane A-A' in Figure 4. [Figure 6] This diagram schematically shows a cross-section of another embodiment of a helicopter lifting platform. [Figure 7] This diagram schematically shows a perspective view of a nacelle cover assembly equipped with a helicopter lifting platform. [Figure 8] This diagram schematically shows a perspective view of a nacelle cover assembly equipped with a helicopter lifting platform. [Figure 9] This is a flowchart of one embodiment of a method for providing a nacelle assembly. [Modes for carrying out the invention]

[0018] Hereinafter, embodiments of the present disclosure are referenced in detail, one or more of which are shown in the drawings. Each embodiment is provided for illustrative purposes only, and not as an limitation of the present disclosure. 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 spirit or scope of the teaching. For example, features illustrated or described as part of one embodiment can also be used in conjunction with another embodiment to bring about further embodiments. Thus, the present disclosure is intended to encompass such modifications and variations within the scope of the appended claims and their equivalents.

[0019] Figure 1 is a perspective view of one embodiment of a wind turbine 10. In this embodiment, the wind turbine 10 is a horizontal-axis wind turbine. Alternatively, the wind turbine 10 may be a vertical-axis wind turbine. In this embodiment, the wind turbine 10 includes a tower 15 extending from a support system 14 on the ground 12, a nacelle 16 mounted on 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 outward from the hub 20. In this embodiment, the rotor 18 has three rotor blades 22. In an alternative embodiment, the rotor 18 includes more or fewer than three rotor blades 22. The tower 15 can be fabricated from tubular steel to define a cavity (not shown in Figure 1) between the support system 14 and the nacelle 16. In an alternative embodiment, the tower 15 is any suitable type of tower having any suitable height. In alternative configurations, the tower may be a hybrid tower comprising concrete and tubular steel sections. Alternatively, the tower may be a partially or fully lattice tower.

[0020] The rotor blade 22 may be spaced apart around the hub 20 so as to facilitate the rotation of the rotor 18 and enable the kinetic energy to be transmitted from the wind to usable mechanical energy and subsequently to electrical energy. The rotor blade 22 is fitted to the hub 20 by coupling the blade root portion 24 to the hub 20 at a plurality of load transfer regions 26. The load transfer regions 26 may have hub load transfer regions and blade load transfer regions (both not shown in FIG. 1). The load induced on the rotor blade 22 is transmitted to the hub 20 via the load transfer regions 26.

[0021] In an embodiment, the rotor blade 22 can have a length ranging from about 15 meters (m) to about 90 m or more. The rotor blade 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 less than 20 m, 37 m, 48.7 m, 50.2 m, 52.2 m, or greater than 91 m. When the wind hits the rotor blade 22 from the wind direction 28, the rotor 18 rotates about the rotor shaft 30. When the rotor blade 22 rotates and is subject to centrifugal force, the rotor blade 22 also receives various forces and moments. Thus, the rotor blade 22 can deflect and / or rotate from a neutral position or an unbiased position to a deflected position.

[0022] Furthermore, the pitch angle of the rotor blade 22, i.e., the angle that determines the orientation of the rotor blade 22 with respect to the wind direction, is changed by the pitch system 32, and the load and power generated by the wind turbine 10 can be controlled by adjusting the angular position of at least one rotor blade 22 with respect to the wind vector. The pitch axis 34 of the rotor blade 22 is also shown. During operation of the wind turbine 10, the pitch system 32 can specifically change the pitch angle of the rotor blade 22 such that the angle of attack of (a part of) the rotor blade is reduced, thereby facilitating a reduction in the rotational speed and / or facilitating a stall of the rotor 18.

[0023] In this embodiment, the blade pitch of each rotor blade 22 is individually controlled by the wind turbine controller 36 or the pitch control system 80. Alternatively, the blade pitch for all of the rotor blades 22 may be simultaneously controlled by the control system.

[0024] Furthermore, in this embodiment, as the wind direction 28 changes, the yaw direction of the nacelle 16 can be rotated about the yaw axis 38 to position the rotor blades 22 with respect to the wind direction 28.

[0025] In this embodiment, the wind turbine controller 36 is shown as being centralized within the nacelle 16, but the wind turbine controller 36 may be a distributed system throughout the entire wind turbine 10, on the support system 14, within the wind farm, and / or at a remote control center. The wind turbine controller 36 includes a processor 40 configured to execute the methods and / or steps described herein. Further, many of the other components described herein include a processor.

[0026] As used herein, the term "processor" is not limited to integrated circuits heretofore referred to in the art as computers, but broadly refers 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 the processor and / or control system may also include memory, input channels, and / or output channels.

[0027] Figure 2 is an enlarged cross-sectional view of a portion of the wind turbine 10. In this embodiment, the wind turbine 10 includes a nacelle 16 and a rotor 18 rotatably coupled to the nacelle 16. More specifically, the hub 20 of the rotor 18 is rotatably coupled to an electric generator 42 positioned within the nacelle 16 by a main shaft 44, a gearbox 46, a high-speed shaft 48, and a coupling 50. In this embodiment, the main shaft 44 is at least partially coaxial with the longitudinal axis (not shown) of the nacelle 16. The rotation of the main shaft 44 drives the gearbox 46, which then drives the high-speed shaft 48 by converting the relatively slow rotational motion of the rotor 18 and the main shaft 44 into the relatively fast rotational motion of the high-speed shaft 48. The latter is connected to the generator 42 to generate electrical energy with the help of the coupling 50. Furthermore, a transformer 90 and / or appropriate electronic equipment, switches, and / or an inverter can be placed in the nacelle 16 to convert the electrical energy generated by the generator 42, which has a voltage of 400V to 1000V, into electrical energy having a medium voltage (10 to 35kV). The electrical energy is then conducted from the nacelle 16 to the tower 15 via power cables.

[0028] The gearbox 46, generator 42, and transformer 90 may be supported by the main support structure frame of the nacelle 16, or optionally embodied as the main frame 52. The gearbox 46 may include a gearbox housing connected to the main frame 52 by one or more torque arms 103. In this embodiment, the nacelle 16 also includes a main front support bearing 60 and a main rear support bearing 62. Furthermore, the generator 42 may be mounted to the main frame 52 by isolation support means 54, in particular to prevent vibrations of the generator 42 from being introduced into the main frame 52 and thereby causing a noise emission source.

[0029] Optionally, the main frame 52 is configured to bear the weight of the components of the rotor 18 and nacelle 16, as well as the entire load caused by the wind and rotational load, and further to introduce these loads into the tower 15 of the wind turbine 10. The rotor shaft 44, generator 42, gearbox 46, high-speed shaft 48, coupling 50, and any associated fastening, support, and / or fixing devices, including but not limited to support 52, front support bearing 60, and rear support bearing 62, may be referred to as the drivetrain 64.

[0030] 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 in the direct-drive wind turbine. Therefore, the generator 42 generally has a much larger diameter than the generator used in a wind turbine with a gearbox 46 in order to provide the same amount of power as a wind turbine with a gearbox.

[0031] The nacelle 16 may also include a yaw drive mechanism 56 that can be used to rotate the nacelle 16 and, consequently, the rotor 18 around the yaw axis 38, thereby controlling the viewpoint of the rotor blades 22 with respect to the wind direction 28.

[0032] To properly position the nacelle 16 with respect to the wind direction 28, the nacelle 16 may also include at least one weather measurement system 58 which may include a wind vane and an anemometer. The weather measurement system 58 can provide the wind turbine controller 36 with information which may include wind direction 28 and / or wind speed. In this embodiment, the pitch system 32 is at least partially located 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 each rotor blade 22 (shown in Figure 1) to modulate 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 Figure 2.

[0033] In this embodiment, the pitch assembly 66 includes a hub 20 and at least one pitch bearing 72 coupled to each rotor blade 22 (shown in Figure 1) to rotate each rotor blade 22 around a 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 so that the pitch drive motor 74 imparts mechanical force to the pitch drive gearbox 76. The pitch drive gearbox 76 is coupled to the pitch drive pinion 78 so 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 so that the rotation of the pitch drive pinion 78 causes the rotation of the pitch bearing 72.

[0034] The pitch drive system 68 is coupled to the wind turbine controller 36 to adjust the pitch angle of the rotor blades 22 upon receiving one or more signals from the wind turbine controller 36. In this embodiment, the pitch drive motor 74 is any suitable motor driven by a 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, but is 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 supplies energy to the components of the wind turbine 10.

[0035] The pitch assembly 66 may also include one or more pitch control systems 80 for controlling the pitch drive system 68 in accordance with control signals from the wind turbine controller 36 in certain priority situations and / or during rotor overspeed. In this embodiment, the pitch assembly 66 includes at least one pitch control system 80 communicably coupled to each pitch drive system 68 in order to control the pitch drive system 68 independently of the wind turbine controller 36. In this embodiment, the pitch control system 80 is coupled to the pitch drive system 68 and the sensor 70. During normal operation of the wind turbine 10, the wind turbine controller 36 can control the pitch drive system 68 to adjust the pitch angle of the rotor blades 22.

[0036] According to one embodiment, for example, a power generator 84 comprising a battery and an electric capacitor is located in or within the hub 20 and coupled to the sensor 70, the pitch control system 80, and the pitch drive system 68 to provide a power source to these components. In this embodiment, the power generator 84 provides a continuous power source to the pitch assembly 66 during the operation of the wind turbine 10. In an alternative embodiment, the power generator 84 provides power to the pitch assembly 66 only during power loss events of the wind turbine 10. Power loss events may include power grid loss or degrading, malfunction of the wind turbine 10's electrical system, and / or failure of the wind turbine controller 36. During a power loss event, the power generator 84 operates to provide power to the pitch assembly 66 so that the pitch assembly 66 can operate during the power loss event.

[0037] In this embodiment, the pitch drive system 68, sensor 70, pitch control system 80, cable, and power generator 84 are each positioned within a cavity 86 defined by the inner surface 88 of the hub 20. In an alternative embodiment, the components may be positioned relative to the outer surface of the hub 20 and coupled directly or indirectly to the outer surface.

[0038] Figure 3 is a schematic perspective view of a nacelle 16 for a wind turbine. Figure 4 shows in more detail the helicopter lifting platform 100 shown in Figure 3 for the wind turbine nacelle cover 161. The nacelle 16 has a roof comprising a composite layer 101. The composite layer 101 includes at least the outer surface of the nacelle 16 and the inner surface of the nacelle 16. Furthermore, the nacelle 16 includes a plurality of spaced-apart metal strips 102 arranged on the outer surface of the composite layer 101. At least some of the metal strips 102 are electrically connected to each other inside the nacelle 16, and at least one grounding connection is connected to one of the metal strips 102.

[0039] Figure 3 shows a nacelle cover assembly 161 with a helicopter lifting platform 100. As seen in the embodiment of Figure 3, the nacelle 16 may also include other components, such as a handrail 170 that defines a safe pedestrian area. Note that in this embodiment, the helicopter lifting platform 100 is integrated with the outer surface of the nacelle cover. However, other configurations are possible in which the helicopter lifting platform 100 is formed as an elevated platform lifted from the nacelle cover assembly 161, or as a platform separate from the nacelle cover assembly 161.

[0040] As described above, the helicopter lifting platform 100 comprises a composite layer 101 including at least an outer and inner surface, and a plurality of spaced-apart metal plates 102 arranged on the outer surface of the composite layer 101. The plurality of metal plates 102 form a conductive network electrically connected to a grounding connection located beneath the composite layer. This conductive network may be formed by interconnecting the plurality of metal plates with conductive plates or cables. This means that static electricity is discharged from the helicopter to the ground upon contact between the conductive wires of the helicopter and any of the plurality of metal plates.

[0041] In some embodiments, as shown in Figure 4, multiple anti-slip surfaces may be arranged between metal conductive plates. Such anti-slip surfaces can provide a safe pedestrian area for personnel performing maintenance and loading / unloading operations.

[0042] In some embodiments, the earthing connection may extend through the composite layer, that is, it may extend from the inner surface to the outer surface of the composite layer, and be electrically connected to one or more of the metal plates 102 on the outer surface.

[0043] The metal plate 102 may also be a long, narrow metal strip.

[0044] Furthermore, Figure 4 shows one embodiment of the arrangement of multiple metal plates 102, where the metal plates 102 are substantially parallel to each other. More precisely, the multiple metal plates 102 may be arranged parallel to each other and at a certain distance from each other. This distance allows for free clearance between the metal plates. In the embodiment, the metal plates may be arranged so that there is a clearance of 25 to 60 centimeters between them (free space between the edges of the metal plates). If the distance between the metal plates is large, it may be necessary to maneuver the helicopter or wire so that the conductive wire contacts one of the multiple metal plates, while if the distance is small, the visibility of the helicopter lifting platform may be reduced to some extent. Such a platform needs to be easily identifiable and is therefore usually painted yellow.

[0045] In embodiments having a non-slip surface, a relatively high ratio of the metal plate surface to the non-slip surface may increase the risk of slipping. A range of 25–60 cm allows sufficient space between the metal plates 102 for a worker to step at least partially on the adjacent non-slip surface for better grip, while at the same time providing several contact areas distributed on the helicopter lifting platform 100 to ensure that the helicopter discharge wire makes contact with at least one of the metal plates 102 before the lifting operation.

[0046] The metal plates may have a thickness in the range of 1.5 to 5 mm and a width in the range of 3 to 8 cm. The appropriate width may be selected taking into consideration the requirement to reduce the risk of slippage, particularly provided by the anti-slip surface adjacent to the metal plates. Other arrangements of the metal plates forming the helicopter lifting platform 100 are also possible, for example, forming a Cartesian grid or a grid with non-linear angles between the metal plates.

[0047] Figure 5 shows a detailed view of a helicopter lifting platform including a longitudinal cross-section through the plane A-A' of Figure 4. As shown in the figure, the metal plate 102 may be located within a recess 102' formed in the outer surface 101' of the composite layer 101. These recesses 102' allow for the integration of the metal plate 102 on the outer surface 101'. This means that the metal plate 102 can be substantially flush with the adjacent surface, or in any case, the height difference with the adjacent surface is reduced. In this embodiment, the recesses 102' are formed between adjacent anti-slip surfaces 104. The shape and size of the recesses 102' may be determined so that the metal plate fits substantially precisely.

[0048] In this embodiment, at least one of the multiple anti-slip surfaces 104 is a sand-painted surface. Thus, the texture of the sand is incorporated into the paint, and the painted surface acquires the surface roughness provided by the sand. Various types of sand can be used to provide various roughness profiles on the surface, and other aggregates such as quartz, silica, or aluminum oxide can also be added to the paint to enhance grip. Since surface friction increases as surface roughness increases, a relatively rough surface provides enhanced grip for workers to walk safely on the platform under wet and dry atmospheric conditions. Therefore, other anti-slip surfaces such as knobbed, ribbed, or corrugated top surfaces may be used for the same purpose.

[0049] In further embodiments, the anti-slip surface may also extend over the entire or a substantial portion of the nacelle roof, beyond the helicopter lifting platform.

[0050] Furthermore, in this embodiment, the height (or thickness) of the anti-slip surface 104 and the height (or thickness) of the metal plates 102 may be selected such that the relative height difference between the average height of the anti-slip surface and the outer surfaces of the multiple metal plates is less than 4 mm, specifically less than 3 mm, and more specifically 1.5 mm. Reducing the height difference between the metal plates 102 and the anti-slip surface 104 results in a more uniform surface, which reduces the risk of misstepping and other related hazards for personnel working near the helicopter lifting platform.

[0051] The longitudinal cross-section of Figure 4 shows that at least one of the multiple metal plates has at least one inwardly projecting element 105. In the illustrated embodiment, metal plate 102 has two inwardly projecting elements 105, 106, which are described below. Furthermore, the embodiment of Figure 4 shows that the composite layer 101 has at least one opening for receiving at least one inwardly projecting element 105, 106 of the metal plate 102, and that the metal plate projecting elements 105, 106 protrude from the inner surface of the composite layer 101. The projecting elements may be welded, press-fitted, screwed, or joined to one or more of the metal plates in a suitable manner. This will become clearer in the embodiment shown in Figure 6.

[0052] Figure 6 shows a cross-sectional view of a helicopter lifting platform 100 in which a metal plate 102 is located on top of a composite layer 101 including an outer surface 101' and an inner surface 101''. The metal plate 102 in this embodiment includes two inwardly projecting elements 105 and 106. The inwardly projecting elements 105 and 106 may be formed integrally with the metal plate 102 or may be attached to the metal plate.

[0053] The first inward projection element 105 is a conductive projection element for receiving the grounding connection 108, while the second inward projection element 106 includes a fastener 106' for fixing the metal plate 102 to the composite layer 101. In this embodiment, the fastener 106' is a threaded nut that matches the threads of the second inward projection element, but other alternative forms are possible. The first inward projection element 105 may include a female connector for receiving a male connector 105' into the grounding portion 108, or a male connector for receiving a female connector into the grounding portion 108. Furthermore, the connection between the female and male connectors may be a screw connection or a fixed connection such as a push-fit connection. Thus, the composite layer 101 may include the same number of openings 107 as the connectors or inward projection elements 105, 106. Embodiments including only the first inward projection element 105 are also possible.

[0054] In other embodiments, the metal plate 102 may be alternatively or additionally fixed to the composite layer by an adhesive material, such as epoxy. This allows the opening 107 of the composite layer 101 to be sealed efficiently and effectively, preventing leakage into the nacelle 16.

[0055] Figures 7 and 8 show a top and bottom perspective view of the nacelle cover assembly 161, respectively, which comprises a helicopter lifting platform 100. The nacelle cover assembly 161 defines the helicopter lifting platform 100 and comprises a composite layer 101 including at least an outer surface 101' and an inner surface 101'', a plurality of spaced-apart metal plates 102 arranged on the outer surface 101' of the composite layer 101, and a plurality of anti-slip surfaces 104 arranged between the metal plates 102 and at least one grounding connection portion 108. Thus, the outer surface 101' of the composite layer 101 defines the helicopter lifting platform 100, which includes the plurality of metal plates 102 and the plurality of anti-slip surfaces 104 interposed between the plurality of metal plates 102. The plurality of metal plates 102 form a conductive network electrically connected to at least one grounding connection portion 108 located beneath the inner surface of the composite layer 101.

[0056] In the embodiments shown in Figures 7 and 8, the composite layer 101 may contain glass fibers and / or polyester resin. The composite layer 101 may additionally or alternatively contain other fibers and resins, such as carbon, basalt, or aramid fibers, and in particular epoxy or vinyl ester resins. Although not shown in Figures 7 and 8, a nacelle cover may be located on top of the internal nacelle frame to provide rigidity and withstand external forces acting on the nacelle cover.

[0057] As previously disclosed in relation to the helicopter lifting platform 100, in other embodiments, the nacelle cover assembly 161 may include a sand-coated anti-slip surface 104, the anti-slip surface 104 forming recesses 102' for receiving a plurality of metal plates 102, and the relative height between the average height of the anti-slip surface 104 and the outer surfaces of the plurality of metal plates 102 is less than 4 mm, specifically less than 3 mm.

[0058] As shown in Figure 8, the helicopter lifting platform 100 (shown by the dotted line) may further include a conductive connection assembly comprising one or more conductive elements 109 located beneath the inner surface 101'' of the composite layer 101 for electrically connecting a plurality of metal plates 102. The conductive connection elements shown in this embodiment are metal plates or metal bars, but other conductive connection elements such as wires or cables are also valid.

[0059] Furthermore, Figure 8 shows that the grounding connection 108 can be alternatively connected to a conductive connection element 109 that simultaneously electrically connects to all metal plates 102. The conductive connection assembly can connect multiple metal plates in series or in parallel.

[0060] In another aspect of this disclosure, Method 600 is provided, which is suitable for providing a nacelle assembly 161. Method 600 is schematically shown in Figure 9.

[0061] The method includes the step of providing a nacelle cover assembly 161 in block 601, comprising a composite layer 101 including at least an outer surface 101' and an inner surface 101'', the outer surface 101' including one or more openings 107. The method also includes the step of providing a plurality of metal plates 102 on the outer surface 101' of the composite layer 101 in block 602.

[0062] Furthermore, Method 600 includes the step of providing a grounding connection 108 inside the nacelle cover assembly and connecting the grounding connection 108 to at least one of the metal plates. Furthermore, Method 600 may also include the step of providing a conductive network between a plurality of metal plates 102 electrically connected to the grounding connection 108. The conductive network defines an electrical path from any of the electrically connected metal plates 102 to the ground, configured to discharge or dissipate the static electricity accumulated in the helicopter when a conductive wire is in contact.

[0063] In some embodiments, at least one of the metal plates 102 may have at least one inwardly projecting element 105, 106 that is inserted into the composite layer opening 107. Method 600 may further include the step of providing a plurality of anti-slip surfaces 104 on the outer surface 101' in the block 603 during the intervals between the plurality of metal plates 102. This step, regardless of the order of subsequent steps, allows for a reduction in the relative height or thickness between the outer surface of the metal plate 102 and the anti-slip surface, thereby reducing the risk of personnel tripping.

[0064] In an embodiment, method 600 for providing a nacelle assembly 161 may include the step of providing a plurality of metal plates 102 substantially parallel to one another. Furthermore, in another embodiment, method 600 may further include the step of providing the metal plates 102, wherein at least one inwardly projecting element 105, 106 of the metal plate is a threaded rod, and method 600 further includes the step of fastening at least one metal plate 102 to the composite layer 101 via a fastening element having threads matching the threaded rod. Alternatively or additionally, the fastening of the metal plates 102 to the composite layer 101 may be performed by applying an adhesive element such as epoxy.

[0065] In further embodiments, method 600 may also include the step of providing a conductive element 109 located on the inner surface 101'' of the composite layer 101 for interconnecting the metal plates.

[0066] Furthermore, method 600 may also include the step of providing a sand-coated non-slip surface 104, in other embodiments, the metal plate 102 has a thickness and the sand-coated surface 104 has an average thickness such that the relative height change between them is less than 3 mm.

[0067] In yet another embodiment, method 600 may include the step of providing a nacelle assembly in accordance with any of the aforementioned technical features.

[0068] This specification discloses the teachings, including preferred embodiments, using examples, and enables those skilled in the art to practice the teachings, including by constructing and using any device or system and by implementing any incorporated methods. The patentable scope of the apparatus is defined by the claims and may include other embodiments that are conceivable to those skilled in the art. Such other examples are intended to be within 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 substantially differ from the language of the claims. Those skilled in the art can construct further embodiments and techniques in accordance with the principles of this application by combining and adapting aspects from the various embodiments described above and other known equivalents for each such aspect. Where reference numerals related to the drawings are placed in parentheses within the claims, those reference numerals are merely for clarity of the claims and should not be construed as limiting the claims. [Explanation of symbols]

[0069] 10 Wind Turbines 12 Ground 14 Support System 15 Towers 16 Nacer 18 rotors 20 Hubs 22 rotor blades 24. Blade base 26 Load transfer region 28 Wind direction 30 rotor shaft 32 Pitch System 34 Pitch axis 36 Wind Turbine Controller 38 Yaw axis 40 processors 42 Generators 44 Main shaft, rotor shaft 46 Gearbox 48 High-speed shaft 50 Couplings 52 Main frame, support 54 Separation support means 56 Yaw drive mechanism 58 Weather Measurement Systems 60 Front support bearing, main front support bearing 62 Rear support bearing, main rear support bearing 64 Drivetrain 66 Pitch Assembly 68 Pitch Drive System 70 sensors 72 pitch bearing 74 Pitch drive motor 76 Pitch Drive Gearbox 78 Pitch Drive Pinion 80 Pitch Control System 84 Power Generators 86 Cavity 88 Inner self 90 Transformer 100 Helicopter Lifting Platforms 101 Composite layer 101' Exterior 101'' Inner self 102 Metal plates, metal strips 102' recess 103 Torque Arm 104 Anti-slip surface 105 Metal plate projection element, first inward projection element 106 Metal plate protruding element, second inward protruding element 106' Fasteners 107 Opening 108 Grounding connection 109 Conductive elements, conductive connecting elements 161 Nacelle Cover Assembly, Wind Turbine Nacelle Cover 170 Handrail 600 ways

Claims

1. A helicopter lifting platform (100) for a wind turbine nacelle cover (161), comprising: a composite layer (101) including at least an outer surface (101') and an inner surface (101''); a plurality of metal plates (102) configured to contact the conductive wires of the helicopter and disposed on the outer surface (101') of the composite layer (101), spaced apart from each other; and the plurality of metal plates (102) form a conductive network electrically connected to a ground connection portion (108) located below the composite layer (101), the helicopter lifting platform (100).

2. The helicopter lifting platform (100) according to claim 1, further comprising a plurality of anti-slip surfaces (104) disposed between the metal plates (102).

3. The helicopter lifting platform (100) according to claim 2, wherein at least one of the plurality of anti-slip surfaces (104) is a sand-coated surface.

4. The helicopter lifting platform (100) according to claim 2, wherein the relative difference in height between the average height of the anti-slip surface (104) and the outer surface of the plurality of metal plates (102) is less than 4 mm.

5. The helicopter lifting platform (100) according to claim 1, wherein the plurality of metal plates (102) are substantially parallel to each other.

6. The helicopter lifting platform (100) according to claim 1, wherein the plurality of metal plates (102) are arranged to have a clearance of 25 to 60 centimeters between each other.

7. The helicopter lifting platform (100) according to claim 1, wherein the plurality of metal plates (102) are located in recesses (102') formed in the outer surface (101') of the composite layer (101).

8. The helicopter lifting platform (100) according to claim 7, wherein the recesses (102') are formed between adjacent anti-slip surfaces (104).

9. The helicopter lifting platform (100) according to claim 1, wherein the ground connection portion (108) extends through the composite layer (101).

10. At least one of the plurality of metal plates (102) comprises at least one inwardly projecting element (105, 106), and the composite layer (101) comprises at least one opening (107) for receiving the at least one inwardly projecting element (105, 106) of the metal plate (102). The lifting platform (100) for a helicopter according to claim 1.

11. The lifting platform (100) for a helicopter according to claim 10, wherein the at least one inwardly projecting element (105, 106) is a conductive projecting element (105) for receiving a ground connection (108).

12. The lifting platform (100) for a helicopter according to claim 1, further comprising a conductive connection assembly located under the inner surface (101'') of the composite layer (101) for electrically connecting the plurality of metal plates (102).

13. The lifting platform (100) for a helicopter according to claim 12, wherein the conductive connection assembly comprises one or more conductive plates (109) and / or conductive cables.

14. A nacelle (16) of a wind turbine (10) comprising the lifting platform (100) for a helicopter according to any one of claims 1 to 13.

15. A wind turbine (10) comprising the nacelle (16) according to claim 14.

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