Lightning bypass system

Abstract

To provide a lightning bypass system for wind turbines.SOLUTION: A lightning bypass system for a blade (22) of a wind turbine, includes a blade connector (110) of an electrical insulating material (114) located substantially in a rotational axis (R) of a blade root (24) of the wind turbine blade (22). The blade connector (110) is electrically connected to a down conductor cable (100) of the blade (22), and includes a core configured to be electrically connected to a first end (111) and a second end (112) of the blade connector (110).SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a lightning bypass system and a method for providing a lightning bypass system, and more particularly, to a lightning bypass system for a wind turbine and related methods. The present disclosure further relates to a wind turbine rotor hub assembly.

Background Art

[0002] Wind turbines are widely used to convert wind power into electricity. The generated electricity is supplied to the power grid and sent to consumers. Wind turbines generally include a tower, on which a nacelle is mounted. A rotor consisting of a rotor hub (or hub) and a plurality of blades is generally rotatably mounted to the nacelle. The plurality of blades utilize the aerodynamic forces generated by the wind to generate a net positive torque on the axis of rotation, thereby creating a mechanical force that is converted into electricity by a generator.

[0003] The blades may be directly connected to the rotor hub or may be connected via a pitch bearing. The pitch system can rotate the blade along its longitudinal axis and change the angle of attack of the wind turbine blade with respect to the incoming airflow. Thereby, the aerodynamic forces acting on the blade can be controlled.

[0004] Wind turbines have evolved rapidly over the past few decades, and the components of wind turbines have been improved to withstand higher loads and adverse weather conditions. Since wind turbines are tall and exposed, it has become important to provide an effective lightning protection system that diverts the discharge from a lightning strike point to the ground without affecting the electrical and structural components of the wind turbine.

[0005] Generally, lightning protection systems include surge traps mounted on wind turbine blades that conduct lightning discharges to grounding connections via lightning conductors located within the blades. One of the main problems with known lightning protection systems is how to conduct lightning discharges from down conductors within the blades to grounding connections located on the wind turbine rotor hub, nacelle, or tower.

[0006] Spark gaps and / or electric brushes are commonly used for this purpose to provide electrical pathways between moving components of a wind turbine, such as the blade roots and rotor hubs and / or rotor hubs and nacelles. However, these approaches have several drawbacks. Providing spark gaps in blades is not a simple solution. These systems include at least two conductive strips positioned close to each other to provide a conductive connection between wind turbine components to bypass connections between them, for example, the connection from the blade root to the rotor hub. In such spark gap systems, the lightning discharge conductor may need to penetrate the wall of the blade body or the blade root flange in order to contact the first conductor strip, and therefore, in some cases, a through-hole must be provided at the blade root. The through-hole adversely affects the structural stability of the blade and requires further reinforcement of the blade. Furthermore, once the down conductor is inserted, the through-hole needs to be sealed to prevent leakage of various substances into the blade. In addition to the above drawbacks, regular maintenance of the spark gap system is necessary to ensure cleanliness and accurate clearance gaps.

[0007] Furthermore, the accumulation of atmospheric sediment and debris, as well as fragments from component wear, can lead to component misalignment and malfunction of the lightning protection system. This can cause lightning discharges to follow the least-resistance path through other wind turbine components instead of the established electrical path to the ground. This means that electrical and / or structural components, such as blade pitch bearings, can act as lightning discharge conductors, significantly shortening their lifespan and resulting in high replacement costs.

[0008] This disclosure provides a method and system for overcoming some of the aforementioned shortcomings, at least partially. [Overview of the project]

[0009] In one aspect of the present disclosure, a lightning bypass system for a wind turbine is provided. The lightning bypass system includes a connector assembly including a blade connector comprising an electrically insulating material. The blade connector further includes a first end configured to be electrically connected to a down conductor cable of the blade and a second end configured to conduct lightning discharges to the rotor hub of the wind turbine. The blade connector further includes a core of conductive material configured to be electrically connected to the first and second ends. The blade connector is configured to be substantially located within the axis of rotation of the blade root of the wind turbine blade.

[0010] According to this embodiment, the fact that the blade connector is substantially located within the rotation axis at the blade root allows for a compact and robust lightning bypass system layout in which the rotation of the blade to correct the blade pitch angle does not cause relative movement between the components of the lightning bypass system. This makes it possible to adjust the length of the conductive elements related to the lightning system and establish conductive paths that do not change their internal position within the blade with the blade pitch angle. These features result in a more secure connection and allow for more efficient use of the internal space of the blade and rotor.

[0011] Furthermore, in this manner, the system bypasses structural and electrical blade components, particularly pitch bearings, that are not intended to be subjected to lightning discharges. In this way, the components of the pitch bearing system are protected from strong temperature gradients, and their lifespan can be improved.

[0012] In another embodiment, a method is provided for providing a lightning bypass assembly system. This method includes providing a blade connector made of an electrically insulating material located substantially within the rotation axis of the blade root of a wind turbine. The blade connector includes a first end, a second end, and a core of conductive material electrically connected to the first and second ends. The method further includes connecting the first end of the blade connector to a down conductor cable of a blade lightning receiver, providing a rotatable connection between the first and second ends of the blade connector, and conductively coupling the blade connector to a lightning grounding system of the wind turbine.

[0013] In a further embodiment of the present disclosure, a wind turbine hub assembly is provided. The assembly includes a wind turbine rotor hub, at least one wind turbine blade, and a lightning bypass system. The wind turbine blade includes a blade root, and the lightning bypass system includes a blade connector fixed to the wind turbine blade and substantially located within the rotation axis of the blade root of the wind turbine, and a hub connector fixed to the rotor hub of the wind turbine, and made of an electrically insulating material. Furthermore, the blade connector includes a first end configured to be electrically connected to a down conductor cable of the blade, a second end configured to conduct lightning discharge to the hub connector, and a core of conductive material configured to electrically connect the first end and the second end, the second end being rotatable relative to the first end.

[0014] Further objectives, advantages, and features of the embodiments of this disclosure will become apparent to those skilled in the art through examination of the specification or through the implementation of this disclosure.

[0015] Throughout this disclosure and with respect to the various embodiments disclosed herein, it should be noted that the blade root portion may be directly coupled to a rotor hub, rotor hub extender, pitch bearing, or any other element of a rotor hub known in the art for this purpose.

[0016] As used throughout this disclosure, electrical insulating materials can be understood as materials that do not allow electric current to flow freely. Electrical insulators have high electrical resistivity. Rubber, glass, and plastics are examples of electrical insulators. As used throughout this disclosure, conductive materials can be understood as materials that allow electric current to flow. Conductive materials have low electrical resistivity. Copper and aluminum wires or cables are examples of conductors. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 shows a schematic perspective view of an example of a wind turbine. [Figure 2] Figure 2 shows an example of a wind turbine hub and nacelle. [Figure 3] Figure 3 is a schematic cross-sectional view of a wind turbine rotor assembly, including an example of a lightning bypass system according to this disclosure. [Figure 4] Figure 4 is a detailed cross-sectional view schematically showing a wind turbine rotor assembly, including another example of a lightning bypass system according to this disclosure. [Figure 5] Figure 5 schematically shows a cross-sectional view of a wind turbine rotor and nacelle assembly, including another example of the lightning bypass system according to this disclosure. [Figure 6] Figure 6 shows another example of a lightning system according to this disclosure in a wind turbine configuration including a main rotor shaft to which the rotor hub is attached. [Figure 7] Figure 7 schematically shows a flowchart of an example of a method for providing a wind turbine blade assembly. [Modes for carrying out the invention]

[0018] Herein, embodiments of the present disclosure are given in detail, with one or more examples shown in the drawings. Each embodiment is provided as a description of the disclosure, not as an limitation. Indeed, it will be apparent to those skilled in the art that various modifications and changes can be made without departing from the scope or spirit of the present disclosure. For example, features illustrated or described as part of one embodiment can be used in conjunction with another embodiment to obtain yet another embodiment. Thus, the present disclosure is intended to encompass modifications and variations that fall within the scope of the appended claims and their equivalents.

[0019] Figure 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 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 and extending outward from the hub 20. In this example, the rotor 18 has three rotor blades 22. In another embodiment, the rotor 18 includes three or more or fewer rotor blades 22. The tower 15 may be made of 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. By another method, the tower may be a hybrid tower including a concrete portion and a tubular steel portion. Additionally, the tower can be a partially or completely lattice tower.

[0020] The rotor blade 22 is spaced from the hub 20 to enable the rotation of the rotor 18 to convert kinetic energy from the wind into usable mechanical energy and thus electrical energy. The rotor blade 26 is fitted to the hub 20 by coupling the blade root portion 24 to the hub 20 in a plurality of load transfer regions 26. The load transfer regions 26 may have a hub load transfer region and a blade load transfer region (neither of which is shown in FIG. 1). The load induced on the rotor blade 26 is transmitted to the hub 20 via the load transfer region 26.

[0021] In an embodiment, the rotor blade 22 can have a length ranging from about 15 meters (m) to about 90 meters or more. The rotor blade 22 can 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 axis 30. When the rotor blade 22 rotates and is subject to centrifugal force, the rotor blade 22 is also subject to various forces and moments. Thus, the rotor blade 22 can deflect and / or rotate from a neutral or non-deflected position to a deflected position.

[0022] Furthermore, to control the load and power generated by the wind turbine 10 by adjusting the angular position of at least one rotor blade 22 with respect to the wind vector, 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, can be changed by the pitch system 32. The pitch axis 34 of the rotor blade 22 is 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 decreases, facilitating a decrease in the rotational speed and / or facilitating a stall of the rotor 18.

[0023] In this example, the blade pitch of each rotor blade 22 is individually controlled by the wind turbine control device 36 or the pitch control system 80. Alternatively, the blade pitch of all 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 may rotate about the yaw axis 38 to position the rotor blades 22 with respect to the wind direction 28.

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

[0026] The term "processor" as used herein is not limited to the integrated circuits referred to as computers in the art, but broadly means a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit, and other programmable circuits, and these terms are used interchangeably herein. It should be understood that the processor and / or the control system can also include a memory, an input channel, and / or an output channel.

[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. Specifically, the hub 20 of the rotor 18 is rotatably coupled to a generator 42 located 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, which in turn 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 inverters can be placed within the nacelle 16 to convert the electrical energy generated by the generator 42, which has a voltage between 400V and 1000V, into electrical energy with a medium voltage (10-35KV). This 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 a main support structure frame of the nacelle 16, which is optionally embodied as a 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 embodiments, the nacelle 16 also includes a main forward support bearing 60 and a main aft support bearing 62. Furthermore, the generator 42 may be attached to the main frame 52 by decoupling support means 54, in particular to prevent vibrations from the generator 42 from being introduced into the main frame 52 and generating a source of noise emission.

[0029] Optionally, the main frame 52 is configured to bear the weight of the rotor 18 and the components of the nacelle 16, as well as the total load generated by the wind and rotational loads, and to further 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 associated fastening, support, and / or fixing devices, including but not limited to the support 52, front support bearing 60 and rear support bearing 62, may be referred to as the drive train 64.

[0030] In some examples, 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. Therefore, they generally have a much larger diameter than the generators used in wind turbines with a gearbox 46 to supply the same amount of power as those used in wind turbines 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 by extension the rotor 18, around the yaw axis 38, in order to control the perspective 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 control device 36 with information including the wind direction 28 and / or wind speed. In this example, 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. Figure 2 shows only one of the three pitch drive systems 68.

[0033] In this example, 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 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 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 pitch bearing 72 is rotated by the rotation of the pitch drive pinion 78.

[0034] The pitch drive system 68 receives one or more signals from the wind turbine controller 36 and is coupled to the wind turbine controller 36 to adjust the pitch angle of the rotor blades 22. In this embodiment, the pitch drive motor 74 is any suitable motor driven by an electric and / or hydraulic system, enabling 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, a hydraulic cylinder, a spring, and / or a servo mechanism. In a particular embodiment, 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 a control signal from the wind turbine controller 36 in certain prioritized situations and / or during overspeed of the rotor 18. In this example, 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 example, 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] In one embodiment, for example, a generator 84 including a battery and an electric capacitor is located inside 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 wind turbine generator 84 provides a continuous source of power to the pitch assembly 66 while the wind turbine 10 is in operation. In another embodiment, the generator 84 supplies power to the pitch assembly 66 only during power loss events of the wind turbine 10. Power loss events can include power grid losses or dips, malfunctions of the wind turbine 10's electrical systems, and / or failures of the wind turbine controller 36. During a power loss event, the power generator 84 operates to supply 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 generator 84 are each located within a cavity 86 defined by the inner surface 88 of the hub 20. In another embodiment, the components may be located on the outer surface of the hub 20 and coupled directly or indirectly to the outer surface.

[0038] Figure 3 is a schematic cross-sectional view of a wind turbine rotor hub, which constitutes an example of the lightning protection device of the present invention. Note that the thickness of the inner wall is shown schematically, and the intersections with the cut surface are not indicated by hatching to avoid clutter.

[0039] Figure 3 shows a lightning bypass system for a wind turbine blade 22, which includes an electrically insulating material 114 and a blade connector 110 configured to be substantially located within the rotation axis R of the blade root 24 of the wind turbine blade. The blade connector 110 includes a first end 111 configured to be electrically connected to a down conductor cable 100 of the blade 22, a second end 112 configured to conduct lightning discharge to the wind turbine hub 20, and a core 113 of conductive material configured to be electrically connected to the first end 111 and the second end 112.

[0040] The blade connector 110 may include an electrically insulated fastener 114 for connecting the blade connector 110 to the blade root, particularly to the blade flange, a plate located within the blade root, or the same. The electrically insulated fastener 114 may be a bushing.

[0041] Furthermore, Figure 3 shows that the second end 112 of the blade connector 110 is rotatable relative to the first end. In the illustrated example, the second end 112 of the blade connector 110 includes a rotatable eye bolt connector 115. However, other types of connectors can also be used.

[0042] In embodiments, the lightning bypass system may further include an electrical connection between a second end of a blade connector and a wind turbine nacelle. The rotatable electrical connection may include a conductive surface, a brush electrically in contact with the conductive surface, and a second end of a blade connector electrically connected to either the conductive surface or the brush. The electrical connection to the conductive surface or the brush may be direct (e.g., directly via a cable) or indirect (further via a connector, interface, or element).

[0043] Furthermore, Figure 3 shows that the connector assembly may further include a hub connector 120 made of an electrically insulating material 123 and fixed to the hub 20 of the wind turbine. The hub connector 120 may also include a core 121 of a conductive material electrically connected to the second end 112 of the blade connector 110 via a conductive element 116.

[0044] The conductive elements can define the path of the connection 200. The path of the connection 200 is conceptually shown by a dashed line. In the example illustrated in Figure 3, the hub connector 120 is electrically coupled to the grounding system 129. However, other arrangements are possible. For example, in the absence of the hub connector 120, the grounding system 129 can be alternatively coupled to the second end 112 of the hub connector 110.

[0045] The hub connector 123 may include fasteners made of electrically insulating material for connecting to a portion of the hub. The fastener 123 may also be a bushing.

[0046] Figure 3 also shows a partial view of a wind turbine blade including the previously disclosed lightning bypass system. More specifically, Figure 3 shows the blade root portion 24 of the wind turbine blade and the arrangement of the lightning bypass system within it. Furthermore, in this example, the wind turbine blade further comprises at least one crossbar 301 positioned across the blade root portion 24 and substantially securing the blade connector 110 within the rotation axis R of the blade root portion 24. Alternatively, an extension of the blade flange 300 or other alternative may be used to secure the blade connector 110 in place. As an example, the wind turbine blade may also include a blade root stiffener or blade flange 300 that covers substantially the entire blade root portion. In the illustrated example, the wind turbine blade consists of both the stiffener or flange 300 and the crossbar 301 connecting its diametrically opposed sides and securing the blade connector 110 in place.

[0047] Figure 4 is a detail view of another example of a lightning bypass assembly, in which some components, such as the grounding system, are not shown to reduce clutter. This figure shows an example of a connection path between the blade connector 110 and the aforementioned hub connector 120. In this example, the conductive element 116 is a metal sling and may include an electrically insulating material cover to protect other components from current passing through it during a lightning discharge. Other types of conductive elements, such as a metal rod or cable, may also be used. Furthermore, Figure 3 shows that the hub connector 120 may include an eye bolt connector 122 to provide an additional degree of rotational freedom and reduce torsional stress on the connection elements.

[0048] The eyebolt connector 122 (in the examples in both Figures 3 and 5) may be rotatably mounted within the electrically insulating bushing 123. Similarly, the eyebolt connector 115 may be rotatably mounted within the electrically insulating bushing 114.

[0049] In this embodiment, the conductive element 116 may define a connection path that serves as a guide for an additional cable bundle 201. In this embodiment, the cable bundle 201 may be a bundle of cables (e.g., fiber optic cables) connected to sensors in the blade. The sensors and cables may form part of a wind turbine subsystem (i.e., a blade monitoring system, a lightning monitoring system, a de-icing system, a blade aviation lightning system) extending from the blade root 24 to the rotor hub 116 according to the connection path. The cable bundle 201 may be coupled to the conductive element 116 by fasteners 202 and / or guided by blade and hub connectors 110, 120.

[0050] Figure 5 is a schematic cross-sectional view of a wind turbine rotor hub and nacelle, including yet another example of a lightning bypass system. The connection between the blades and the down conductors to the hub may generally be the same as or similar to the embodiments shown in Figures 3 and 4.

[0051] In the example shown in Figure 5, the lightning bypass system further comprises a rotatable electrical connection between the second end 112 of the blade connector 110 and the wind turbine nacelle 16. The rotatable electrical connection includes a conductive surface 126 and a brush 128 that provides electrical contact with the conductive surface 126. The lightning bypass system further comprises a conductive connection between the second end 112 of the blade connector 110 and either the conductive surface 126 or the brush 128. In the illustrated example, the conductive cable 125 is physically connected to the hub connector 120, which is connected to the blade connector 110 and the lightning protection system in the blade, as previously described with reference to Figures 3 and 4. However, the hub connector 120 can be omitted, and the conductive cable 125 can be directly coupled to the blade connector 110.

[0052] In the example shown in Figure 5, the conductive surface 126 is fixed to the wind turbine hub 20, and the brush 28 is fixed to the wind turbine nacelle 16, providing an electrical path between the rotatable wind turbine hub 20 and the wind turbine nacelle 16.

[0053] In this example, the conductive surface 126 is fixed to the rotor hub 20 by a non-conductive support 127 to prevent lightning discharge from being transmitted to the rotor hub 20 and to avoid lightning discharge passing through the rotor bearing 21'. The brush 128 may be fixed to the nacelle 16 following a similar approach, but the corresponding support is not shown in this figure to reduce clutter. Alternatively, the conductive surface 126 may be fixed to the wind turbine nacelle 16 and the brush 128 may be fixed to the wind turbine hub 20 to provide an electrical path between the wind turbine hub 20 and the wind turbine nacelle 16.

[0054] In the illustrated example, the conductive surface 126 is an annular metal disk, but the geometric shape of this component can be adapted to the specific requirements of the lightning system.

[0055] In another embodiment, Figure 5 also shows a wind turbine hub assembly including a wind turbine rotor hub 20, at least one wind turbine blade 22, and a lightning bypass system. The wind turbine blade 22 includes a blade root 24, and the lightning bypass system includes a blade connector 110 made of an electrically insulating material 114 fixed to the wind turbine blade and substantially located within the rotation axis R of the blade root 24 of the wind turbine, and a hub connector 120 made of an electrically insulating material 123 fixed to the rotor hub 20 of the wind turbine. The blade connector 110 comprises a first end 111 configured to be electrically connected to a down conductor cable 100 of the blade, a second end 112 configured to conduct lightning discharge to the hub connector 120, and a core 113 of a conductive material configured to electrically connect the first end 111 to the second end 112, the second end 112 being rotatable relative to the first end.

[0056] The blade connector includes a bushing made of an electrically insulating material.

[0057] Furthermore, the wind turbine hub assembly may include a hub connector 120 in which the conductive element 116 is electrically connected to the second end 112 of the blade connector 110, and the conductive element includes a core 121 of conductive material that defines the connection path 200.

[0058] The wind turbine hub assembly may further include a conductive surface 126 fixed to the wind turbine rotor hub 20. In embodiments, the assembly may further include a brush 128 for providing electrical contact with the conductive surface 126, and a conductive cable 125 electrically connected to the hub connector 120 and the conductive surface 126. The brush 128 is fixed to the wind turbine nacelle 16 and provides an electrical path between the wind turbine rotor hub 20 and the wind turbine nacelle 16.

[0059] Furthermore, Figure 5 shows that the rotor hub 20 is attached to the frame 21 via a hub bearing 21', forming a rotatable connection between the hub and the frame. The frame 21 supporting the rotor hub 20 may be connected to another frame or other structural support within the nacelle 16.

[0060] In the embodiment, the rotor hub may be connected to the rotor shaft via a flexible coupling. The flexible coupling may be configured to transmit torsional loads, but may also be configured to avoid (or at least reduce) transmitted bending loads. The rotor shaft may directly drive the generator, or it may form a low-speed shaft that forms the input shaft of a gearbox.

[0061] In the example shown in Figure 5, a direct-drive wind turbine is schematically represented. In this example, the rotor hub 20 may be coupled to an outer structure 162 which may include or be connected to a generator rotor. Thus, the outer structure 162 may rotate around an inner nacelle structure 161 which may include or form a generator stator.

[0062] Figure 6 shows another example of a lightning system according to the present disclosure in a wind turbine configuration including a main rotor shaft 44 to which a rotor hub 20 is attached. The main shaft 44 is configured to be driven and may be operably coupled directly or indirectly to the shaft of the generator rotor. In this example, the rotor shaft 44 is rotatably supported in the nacelle 16 by a main bearing 25.

[0063] Therefore, the lightning system according to this disclosure is suitable for a wide range of wind turbine configurations, namely, wind turbines including, in particular, direct-drive wind turbines or gearbox systems.

[0064] In another embodiment of this disclosure, Method 600 is provided, which is suitable for providing a lightning bypass system. Method 600 is schematically shown in Figure 7.

[0065] The method includes, in block 601, providing a blade connector 110 comprising an electrically insulating material 114 substantially located within the rotation axis R of the blade root 24 of a wind turbine (wind turbine blade), the blade connector 110 comprising a first end 111, a second end 112, and a core 113 of conductive material electrically connected to the first end 111 and the second end 112. The blade connector 110 may be an electrically insulated bushing, or may include an electrically insulated bushing.

[0066] Method 600 also includes, in block 602, connecting the first end 111 of the blade connector 110 to a down conductor cable 100 connected to the surge trap of the blade. Furthermore, Method 600 includes, in block 603, providing a rotatable connection between the first end 111 and the second end 112 of the blade connector 110. The rotatable connection can be provided, for example, by an eyebolt connector 115 located at the second end 112 of the blade connector 110.

[0067] Furthermore, method 600 includes electrically coupling the second end of the blade connector to the wind turbine's lightning grounding system 129 in block 604.

[0068] In the embodiment, the method 600 for providing a lightning bypass system may include providing a conductive surface 126 fixed to one of the wind turbine rotor hub 20 and the wind turbine nacelle 16 and electrically insulated from them. In addition, it may include providing a brush 128 for electrically contacting the conductive surface 126, the brush 128 being fixed to the other of the wind turbine rotor hub 20 and the turbine nacelle 16 to which the conductive surface 126 is fixed, and providing an electrical path between the wind turbine hub 20 and the wind turbine nacelle 16. A cable 125 is then electrically coupled from the second end 112 of the blade connector 110 to the conductive surface 126.

[0069] In other embodiments, Method 600 may include providing a hub connector 120 made of an electrically insulating material 123 fixed to the hub 20 of a wind turbine. The hub connector 120 includes a core 121 of a conductive material. The second end 112 of the blade connector 110 is electrically coupled to the hub connector 120 via a conductive element 116, the conductive element 116 defining a connection path 200. A cable bundle 201 is then guided along the connection path 200 defined by the conductive element 116. The cable bundle 201 may be part of a blade subsystem, such as a blade monitoring system, a lightning monitoring system, a de-icing system, or a blade aerial lightning system, among other things.

[0070] This description uses examples to disclose teachings including preferred embodiments and to enable a person skilled in the art to implement the teachings disclosed herein, including manufacturing and using any apparatus or system and carrying out any incorporated methods. The patentable scope is defined by the claims and may include other examples that may arise for a person skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims. Aspects from the various embodiments described, as well as other known equivalents to each such aspect, may be combined and harmonized by a person skilled in the art to construct additional embodiments and technologies in accordance with the principles of this application. Where reference numerals related to the drawings are enclosed in parentheses in the claims, they are intended solely to enhance the understanding of the claims and should not be construed as limiting the scope of the claims. [Explanation of symbols]

[0071] 10 Wind Turbines 12 Ground 14 Support System 15 Towers 16 Nacer 18 rotors 20 Hubs 21' Rotor bearing 22 rotor blades 24. Blade base 26 rotor blades 28 Wind direction 30 rotor shaft 32 Pitch System 34 Pitch axis 36 Wind Turbine Control Device 38 Yaw axis 40 processors 42 Generators 44 Main shaft 46 Gearbox 48 High-speed shaft 50 Couplings 52 Mainframes 54 Decoupling support means 56 Yaw drive mechanism 58 Weather Measurement Systems 60 Main front support bearing 62 Main rear support bearing 64 drive train 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 Generators 86 Cavity 88 Inner self 90 Transformer 100 Down Conductor Cable 103 Torque Arm 110 Blade Connectors 111 First end 112 Second end 113 cores 114 Electrical Insulation Fasteners 115 Eyebolt Connector 116 Conductive elements 120 Hub Connector 123 Hub Connector 125 Conductive Cable 126 Conductive Surface 127 Non-conductive support 128 brushes 129 Grounding System 161 Inner structure 162 Outer structure 200 Connection points / connection paths 201 Cable bundle 202 Fasteners 300 Blade Flange 301 Crossbar

Claims

1. A lightning bypass system for a blade (22) of a wind turbine (10), including an electrical insulating material (114) and including a blade connector (110) configured to be disposed substantially within a rotational axis (R) of a blade root portion (24) of the wind turbine blade (22), wherein the blade connector (110) has a first end portion (111) configured to be electrically connected to a down conductor cable (100) of the blade (22), a second end portion (112) configured to conduct a lightning discharge to a rotor hub (20) of the wind turbine (10), and a core (113) of a conductive material configured to be electrically connected to the first end portion (111) and the second end portion (112), the blade connector (110) comprises an electrical insulating fastener (114) for connecting the blade connector (110) to the blade root portion (24), a lightning bypass system, wherein the first end portion (111) and the second end portion (112) of the blade connector (110) form a rotatable connection.

2. The lightning bypass system according to claim 1, wherein at least the second end portion (112) of the blade connector (110) includes a rotatable eye bolt connector (115).

3. The lightning bypass system further comprises a rotatable electrical connection between the second end portion (112) of the blade connector (110) and the wind turbine nacelle (16), wherein the rotatable electrical connection includes a conductive surface (126), and a brush (128) providing electrical contact with the conductive surface (126), the lightning bypass system according to claim 1, wherein the second end portion (112) of the blade connector (110) is electrically connected to one of the conductive surface (126) and the brush (128).

4. The lightning bypass system according to claim 3, wherein one of the conductive surface (126) and the brush (128) is fixed to the wind turbine rotor hub (20) and the other of the conductive surface (126) and the brush (128) is fixed to the wind turbine nacelle (16) to provide an electrical path between the wind turbine rotor hub (20) and the wind turbine nacelle (16).

5. The lightning bypass system according to claim 3, wherein the conductive surface (126) is an annular metal disk.

6. The lightning bypass system according to claim 1, further comprising a hub connector (120) made of an electrically insulating material (123) fixed to a rotor hub (20) of a wind turbine (10), and a hub connector (120) including a core (121) made of a conductive material, wherein the core (121) is electrically connected to a second end (112) of a blade connector (110) via a conductive element (116).

7. The lightning bypass system according to claim 6, wherein the conductive element (116) includes an electrically insulating material cover.

8. The lightning bypass system according to claim 6, wherein a connection path (200) defined by the conductive element (116) functions as a guide to a cable bundle (201).

9. The lightning bypass system according to claim 6, wherein the hub connector (120) includes a rotatable eye bolt connector (122).

10. The lightning bypass system according to claim 1, wherein the electrical insulating fastener (114) connects the blade connector (110) to a blade flange or a plate disposed at a blade root portion.

11. A wind turbine blade including the lightning bypass system according to any one of claims 1 to 10.

12. The wind turbine according to claim 11, wherein the blade connector is attached to a blade flange.

13. A method of providing a lightning bypass system within a wind turbine (10), comprising: providing a blade connector (110) including an electrically insulating material (113) substantially disposed within a rotation axis (R) of a blade root portion (24) of the wind turbine (10), the blade connector (110) including an electrical insulating fastener (114) for connecting the blade connector (110) to the blade root portion (24), the blade connector (110) including a first end (111), a second end (112), and a core (113) of a conductive material electrically connected to the first end (111) and the second end (112); connecting a first end (111) of the blade connector (110) to a down conductor cable (100) from a lightning arrester of the blade (22); providing a rotatable connection (115, 116, 122) between the first end (111) and the second end (112) of the blade connector (110). Conductively coupling a blade connector (110) to a lightning grounding system (129) of a wind turbine (10); A method comprising the above steps.

14. Providing a conductive surface (126) fixed to one of a wind turbine rotor hub (20) and a wind turbine nacelle (16) and electrically insulated therefrom; Providing a brush (128) in electrical contact with the conductive surface (126), the brush (128) being fixed to the other of the wind turbine rotor hub (20) and the turbine nacelle (16) to which the conductive surface (126) is fixed, and providing an electrical path between the wind turbine rotor hub (20) and the wind turbine nacelle (16); the above step; Conductively coupling a second end (112) of the blade connector (110) to the conductive surface (126); The method according to claim 13, comprising the above steps.

15. Fixing a hub connector (120) including an electrical insulating material (123) to a rotor hub (20) of a wind turbine (10), the hub connector (120) comprising a core (121) of conductive material; the above step; Conductively coupling a second end (112) of a blade connector (110) to the hub connector (120) via a conductive element (116), the conductive element (116) defining a connection path (120); the above step; Guiding a cable bundle (201) along a connection path (200) defined by the conductive element (116); The method according to claim 13 or 14, comprising the above steps.

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