Connection elements for lightning protection systems for wind turbine blades

Abstract

A wind turbine blade having a connection element for a lightning protection system for a wind turbine blade is disclosed. The connection element includes: a root end portion configured to be mechanically and electrically connected to a root region of the wind turbine blade; and a conductor portion including a first conductor portion and a second conductor portion, wherein the first conductor portion is configured to receive and be electrically connected to a stripped portion of a downlead, and the second conductor portion is configured to receive and be mechanically connected to an insulating portion of the downlead.

Description

Technical Field

[0001] The present invention relates to a connecting element and a wind turbine blade including the connecting element, as well as an associated method for a lightning protection system, the connecting element being such as a connecting element for connecting a down conductor of a lightning protection system to a wind turbine blade. Background Technology

[0002] As wind turbines and their blades increase in size, the risk of lightning strikes on wind turbines also increases. Therefore, there is growing interest in providing lightning protection for wind turbines, and especially for their blades.

[0003] It is known that lightning receivers are provided for wind turbine blades, which are electrically connected to downleads inside the blades and connected to the ground via the wind turbine hub and nacelle. The downleads inside the blades can be connected, for example, to the root region of the wind turbine blades, such as the root end of the wind turbine blades, by connecting elements (also known as shoe terminals).

[0004] To reduce mechanical stress on the conductive portion of the downlead, it can be secured, for example, by gluing it to the interior of the blade near the electrical connection. However, mechanical failures may still be observed near the connection between the downlead and the blade. Summary of the Invention

[0005] The purpose of this disclosure is to provide methods and components for connecting down conductors of lightning protection systems to the root region of wind turbine blades (such as the root end flange of a wind turbine blade) in a more durable manner, less susceptible to fatigue or other mechanical failures. Another purpose of this disclosure is to provide components and methods that facilitate easier and more convenient connections of down conductors to the root region of wind turbine blades.

[0006] Therefore, this disclosure relates to a connection element for a lightning protection system for a wind turbine blade, the wind turbine blade including a root region, an airfoil region with a tip, a pressure side, a suction side, and a chord extending between a leading edge and a trailing edge. The connection element is configured to connect a downlead of the lightning protection system to the root region of the wind turbine blade, such as a root end flange of the root region. The connection element includes: a root end portion configured to be mechanically and electrically connected to the root region of the wind turbine blade; and a conductor portion including a first conductor portion and a second conductor portion, wherein the first conductor portion is configured to receive and be electrically connected to a stripped part of the downlead, and the second conductor portion is configured to receive and be mechanically connected to an insulating part of the downlead.

[0007] Connecting elements (such as the conductor portion of a connecting element) can define the axis of the conductor portion. For example, the axis of the conductor portion can be substantially coaxial with the longitudinal direction of the downlead (e.g., when the downlead is housed in the conductor portion).

[0008] A wind turbine blade is also disclosed, comprising a root region, an airfoil region with a tip, a pressure side, a suction side, and a chord extending between the leading and trailing edges. The wind turbine blade also includes a lightning protection system comprising a downleader and a connecting element, such as the one disclosed above, connecting the downleader to the root region. The connecting element comprises: a root end portion mechanically and electrically connected to the root region of the wind turbine blade; and a conductor portion comprising a first conductor portion and a second conductor portion, wherein the first conductor portion accommodates and is electrically connected to a stripped portion of the downleader, and the second conductor portion accommodates and is mechanically connected to an insulating portion of the downleader. The conductor portion axis of the conductor portion is substantially coaxial with the longitudinal direction of the downleader.

[0009] A method for connecting a downleader of a lightning protection system for a wind turbine blade to the root region of the wind turbine blade (such as the root end flange of the root region) is also disclosed. The wind turbine blade includes a root region, an airfoil region with a tip, a pressure side, a suction side, and a chord extending between the leading and trailing edges. The downleader includes a conductive element and an insulating sheath covering the conductive element. The method includes: providing a connecting element, such as the connecting element disclosed above, the connecting element including a root end portion and a conductor portion, the conductor portion including a first conductor portion and a second conductor portion; removing an insulating sheath from a portion of the end of a downlead to provide a stripped portion and an insulating portion of the downlead; inserting the end of the downlead into the conductor portion of the connecting element such that the stripped portion is received by the first conductor portion and the insulating portion is received by the second conductor portion of the connecting element, and such that the longitudinal direction of the downlead is substantially coaxial with the conductor portion axis of the conductor portion; fastening the second conductor portion to the insulating portion; and fastening the root end portion of the connecting element to the root region of a wind turbine blade, such as a root end flange of the root region.

[0010] When the downlead is connected to the root region of a wind turbine blade, the downlead and connector element can be located inside the wind turbine blade, for example, on the distal side of the root end flange. The downlead, when connected by the connector element, can extend from the root region, such as from the root end flange. The downlead can extend towards the tip of the wind turbine blade.

[0011] The advantage of this disclosure is that it provides a more convenient and easier connection between the down conductor of a lightning protection system and the root region (such as the root end flange of the root region), and it can provide increased strength between the down conductor of a wind turbine blade and the root region (e.g., the root end flange) and the possibility of reduced mechanical failure of the connection.

[0012] The advantage of this disclosure is that the disclosed connecting element provides cable unloading, for example, by mechanically fastening it to the insulating sheath of the down conductor. This reduces the load on the critical section of the transition between the down conductor and the connecting element. Furthermore, this disclosure allows for reduced cable bending during the transition between the down conductor and the connecting element.

[0013] The first conductor portion and the second conductor portion can be formed integrally. Alternatively or additionally, the conductor portion and the root end portion can be formed integrally.

[0014] The conductor portion (such as a first conductor portion and / or a second conductor portion) may include an aperture for receiving a down conductor, such as a portion of a down conductor. The conductor portion (such as a first conductor portion and / or a second conductor portion) may, for example, be substantially cylindrical along the axis of the conductor portion.

[0015] The first conductor portion may have a first internal cross-sectional distance, such as a first internal cross-sectional diameter. The first internal cross-sectional distance allows the first conductor portion to accommodate the stripped portion of the down conductor. The first internal cross-sectional distance may be equal to or slightly larger than the diameter of the stripped portion of the down conductor; for example, the first internal cross-sectional distance may be 0.1-2 mm larger than the diameter of the stripped portion of the down conductor. The first internal cross-sectional distance may be smaller than the diameter of the insulation portion of the down conductor.

[0016] The second conductor portion may have a second internal cross-sectional distance, such as a second internal cross-sectional diameter. The second internal cross-sectional distance may be greater than the first internal cross-sectional distance. The second internal cross-sectional distance allows the second conductor portion to accommodate the insulation portion of the down conductor. The second internal cross-sectional distance may be equal to or slightly greater than the diameter of the insulation portion of the down conductor; for example, the first internal cross-sectional distance may be more than the diameter of the insulation portion of the down conductor by 0.1-2 mm.

[0017] The conductor portion may have a material thickness along a radial axis perpendicular to the conductor portion's axis. For example, the material thickness may be between the inner and outer circumferences of the conductor portion. The material thickness may be substantially uniform in a cross-section perpendicular to the conductor portion's axis. The material thickness of the conductor portion may vary at different locations along the conductor portion's axis; for example, the material thickness of the conductor portion may vary between different sections of the conductor portion. A first conductor portion may have a first material thickness along a radial axis perpendicular to the conductor portion's axis. A second conductor portion may have a second material thickness parallel to the radial axis. The second material thickness and the first material thickness may be the same. Alternatively, the second material thickness may be greater than the first material thickness. Alternatively, the second material thickness may be less than the first material thickness.

[0018] The connecting element can be fundamentally rigid. For example, the connecting element can be made of metal (such as copper, such as tin-plated copper). The connecting element can be annealed, for example, the connecting element can be made of annealed metal (such as copper, such as tin-plated copper).

[0019] The root end portion may include a fastening section, for example for engaging with a fastening element (e.g., a bolt or screw or the like) to secure a connecting element to the root region of a wind turbine blade, such as a root end flange of a wind turbine blade. The fastening section may include a hole for receiving the fastening element. For example, the hole may be an internal thread for engaging with a opposing thread of the fastening element.

[0020] Connecting elements (such as the root end portion of a connecting element) may include an internal separation structure. This internal separation structure can separate the fastening element (e.g., when inserted into a hole in the fastening section) from the stripped portion of the downlead. The internal separation structure may be conductive. The internal separation structure can provide mechanical strength to the connecting element.

[0021] The root end portion, for example, can be substantially cylindrical along the axis of the conductor portion. The hole in the fastening section can extend along the axis of the conductor portion. The connecting element, for example, can be substantially cylindrical along the axis of the conductor portion. The connecting element can be substantially cylindrical, having a first end forming the root end portion and a second end forming the conductor portion.

[0022] A lightning protection system's down conductor may include a conductive element and an insulating sheath covering that conductive element. The longitudinal direction of the down conductor may be the direction of the conductive element. The insulating sheath may be coaxial with the longitudinal direction of the down conductor.

[0023] Connecting a connecting element to a downlead may include removing the insulating sheath from a portion of the end of the downlead to provide a stripped portion of the downlead. The stripped portion of the downlead may be inserted into and received by a first conductor portion to form an electrical connection between the conductive element of the downlead and the connecting element. The insulating portion of the downlead may be received and secured to a second conductor portion of the connecting element.

[0024] Fastening the second conductor portion to the insulating portion may include crimping the second conductor portion. For example, crimping the second conductor portion may include reducing the cross-sectional distances of the second conductor portion, such as a first cross-sectional distance and / or a second cross-sectional distance. The cross-sectional distances (such as the first and / or second cross-sectional distances) may be perpendicular to the longitudinal direction of the downlead and / or the axis of the conductor portion. For example, crimping the second conductor portion may include reducing the first cross-sectional distance such that the first cross-sectional distance is shorter than the second cross-sectional distance of the second conductor portion. Alternatively or additionally, crimping the second conductor portion may include reducing the first and second cross-sectional distances such that the first and second cross-sectional distances are shorter than a third cross-sectional distance of the second conductor portion. The first cross-sectional distance may be perpendicular to the second cross-sectional distance. The third cross-sectional distance may span an angle of 45 degrees with the first and second cross-sectional distances.

[0025] The first conductor portion can be fastened to the stripped portion of the downlead. Therefore, the method may further include fastening the first conductor portion to the stripped portion of the downlead.

[0026] Securing the first conductor portion to the stripper portion may include crimping the first conductor portion. For example, crimping the first conductor portion may include reducing the cross-sectional distance of the first conductor portion, such as a first cross-sectional distance and / or a second cross-sectional distance. The cross-sectional distance (such as the first cross-sectional distance and / or the second cross-sectional distance of the first conductor portion) may be perpendicular to the longitudinal direction of the downlead and / or the axis of the conductor portion. For example, crimping the first conductor portion may include reducing the first cross-sectional distance of the first conductor portion such that the first cross-sectional distance is shorter than the second cross-sectional distance of the first conductor portion. Alternatively or additionally, crimping the first conductor portion may include reducing the first cross-sectional distance and the second cross-sectional distance of the first conductor portion such that the first cross-sectional distance and the second cross-sectional distance are shorter than a third cross-sectional distance of the first conductor portion. The first cross-sectional distance may be perpendicular to the second cross-sectional distance of the first conductor portion. The third cross-sectional distance of the first conductor portion may cross an angle of 45 degrees with the first cross-sectional distance and the second cross-sectional distance of the first conductor portion.

[0027] The connecting element (such as the conductor portion of the connecting element) may be surrounded by a second insulating sheath. Therefore, the method may further include surrounding the connecting element and / or the conductor portion of the connecting element with the second insulating sheath. The second insulating sheath may protect (e.g., environmentally protect) the connecting element and / or the conductor portion of the connecting element. The second insulating sheath may be a shrinkable tube, such as a heat-shrinkable tube. The second insulating sheath may be applied after the second conductor portion is secured to the insulating portion of the downlead and / or after the first conductor portion is secured to the stripped portion of the downlead. Attached Figure Description

[0028] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. The drawings illustrate one mode of implementing the invention and should not be construed as limiting other possible embodiments falling within the scope of the appended claims.

[0029] Figure 1 This is a schematic diagram illustrating an exemplary wind turbine.

[0030] Figure 2 This is a schematic diagram illustrating an exemplary wind turbine blade.

[0031] Figure 3 This is a schematic diagram illustrating an exemplary connecting element.

[0032] Figure 4 This is a schematic diagram illustrating an exemplary connecting element.

[0033] Figure 5 This is a schematic diagram of a longitudinal cross-sectional view of an exemplary connecting element.

[0034] Figure 6 This is a schematic diagram of a cross-section of an exemplary connecting element.

[0035] Figure 7a , 7b 7c and 7d are schematic diagrams of longitudinal cross-sectional views of the exemplary connecting elements shown in the illustrations.

[0036] Figure 8 This is a flowchart illustrating an exemplary method of connecting exemplary connecting elements. Detailed Implementation

[0037] Figure 1 The illustration shows a conventional modern upwind turbine 2 based on the so-called "Danish concept," with a tower 4, a nacelle 6, and a rotor with a generally horizontal rotor shaft. The rotor includes a hub 8 and three blades 10 extending radially from the hub 8, each blade 10 having a blade root 16 closest to the hub and a blade tip 14 furthest from the hub 8.

[0038] Figure 2 A schematic view of an exemplary wind turbine blade 10 is shown. The wind turbine blade 10 has the shape of a conventional wind turbine blade with a root end 17 and a tip end 15, and includes a root region 30 closest to the hub, a profiled or airfoil region 34 furthest from the hub, and a transition region 32 between the root region 30 and the airfoil region 34. The blade 10 includes a leading edge 18 facing the direction of rotation of the blade 10 when the blade is mounted on the hub, and a trailing edge 20 facing the opposite direction of the leading edge 18.

[0039] Airfoil region 34 (also called the contour region) has an ideal or near-ideal blade shape for generating lift, while root region 30 has a generally circular or elliptical cross-section for structural reasons, such as making it easier and safer to mount the blade 10 to the hub. The diameter (or chord) of root region 30 may be constant along the entire root region 30. Transition region 32 has a transition profile that gradually changes from the circular or elliptical shape of root region 30 to the airfoil profile of airfoil region 34. The chord length of transition region 32 typically increases with increasing distance r from the hub. Airfoil region 34 has an airfoil profile with a chord extending between the leading edge 18 and trailing edge 20 of blade 10. The width of the chord decreases with increasing distance r from the hub.

[0040] The shoulder 40 of the blade 10 is defined as the location where the blade 10 has its maximum chord length. The shoulder 40 is typically provided at the boundary between the transition region 32 and the airfoil region 34.

[0041] It should be noted that the chords of different sections of the blade are generally not located in a common plane because the blade can be twisted and / or bent (i.e., pre-bent), thus providing a correspondingly twisted and / or bent path for the chord plane to compensate for the local velocity of the blade, which depends on the radius from the hub, which is the most common case.

[0042] The wind turbine blade 10 includes a blade shell that may comprise two blade shell portions, typically made of fiber-reinforced polymer, namely a first blade shell portion 24 and a second blade shell portion 26. The first blade shell portion 24 is typically a pressure-side or upwind blade shell portion. The second blade shell portion 26 is typically a suction-side or downwind blade shell portion. The first blade shell portion 24 and the second blade shell portion are typically glued together along a bonding line or glued joint 28 that extends along the trailing edge 20 and leading edge 18 of the blade 10. Typically, the root ends of the blade shell portions 24, 26 have a semi-circular or semi-elliptical external cross-sectional shape.

[0043] The wind turbine blade 10 also includes a lightning protection system 42. The lightning protection system 42 includes a lightning receiver 44 positioned near the tip 15 of the wind turbine blade 10. The lightning protection system 42 includes a down conductor 50 for connecting the lightning receiver 44 to ground. The down conductor 50 is connected to a root region 30 of the blade 10, such as a root end flange 92 of the root region 30. The down conductor 50 extends from the root region 30 toward the tip 15. The down conductor 50 extends from the root region 30 to the lightning receiver 44. Another conductor (not shown) can electrically connect the root end flange 92 to ground, thereby forming an electrical connection from the lightning receiver 44 to ground. The lightning protection system 42 may further include connection elements for connecting the down conductor to the root region 30 of the blade 10 (such as the root end flange 92).

[0044] Figure 3 An exemplary connecting element 60 is shown, such as connecting the downlead 50 to, for example, as per... Figure 2The connecting element 60 is located on the distal side of the flange 92 of the wind turbine blade. The connecting element includes a root end portion 62 and a conductor portion 64. The conductor portion 64 includes a first conductor portion 66 and a second conductor portion 68. The conductor portion axis 70 of the conductor portion 64 is substantially coaxial with the longitudinal direction of the downlead 50 when it is housed within the conductor portion 64. As shown, the conductor portion 64 (such as the first conductor portion 66 and the second conductor portion 68) and the root end portion 62 may be substantially coaxial with the conductor portion axis 70. As shown, the conductor portion 64 (such as the first conductor portion 66 and the second conductor portion 68) and the root end portion 62 may be substantially symmetrical about the conductor portion axis 70. The first conductor portion 66 and the second conductor portion 68 are substantially cylindrical along the conductor portion axis 70.

[0045] The first conductor portion 66 and the second conductor portion 68 can be integrally formed. The root end portion 62 and the conductor portion 64 can also be integrally formed. The connecting element 60 can be a rigid element, for example, made of metal, which can be annealed. For example, the connecting element 60 can be made of tin-plated copper.

[0046] Conductor portion 64 may accommodate downlead 50 (such as an end of downlead 50), and conductor portion 64 (such as first conductor portion 66 and / or second conductor portion 68) may be crimped to secure to downlead 50. First conductor portion 66 is configured to accommodate and optionally secure to a stripped portion of downlead. Second conductor portion 68 is configured to accommodate and secure to an insulating portion of downlead.

[0047] Figure 4 An exemplary connecting element 60 is shown, such as Figure 3 The connecting element 60 is shown. The connecting element includes a root end portion 62 and a conductor portion 64, the conductor portion 64 including a first conductor portion 66 and a second conductor portion 68 having a conductor portion axis 70. The connecting element 60 includes a fastening section (not shown) at the root end portion 62 for engaging with a fastening element 90 such as a screw or bolt to fasten the connecting element 60 to, for example, the root region of a wind turbine blade, such as a root end flange 92.

[0048] Figure 5 A longitudinal cross-sectional view of an exemplary connecting element 60 is shown, such as... Figure 3 or Figure 4The connecting element 60 is shown. The connecting element 60 is connected to the root end flange 92 of the wind turbine blade. The connecting element 60 includes a root end portion 62 having a conductor portion axis 70 and a conductor portion 64. As shown, the conductor portion 64 includes a first conductor portion 66 and a second conductor portion 68, wherein the first conductor portion 66 is configured to receive and be electrically connected to a stripped portion 52 of the downlead 50. As shown, the second conductor portion 68 is configured to receive and be mechanically connected to an insulating portion 54 of the downlead 50. The second conductor portion 68 can be crimped to mechanically connect to the insulating portion 54 of the downlead. The connecting element 60 includes a fastening section 80 at the root end portion 62 for engagement with a fastening element 90. As shown, the fastening section 80 is configured to fasten the connecting element 60 to the root region of the wind turbine blade, such as the root end flange 92. As shown, the fastening section 80 may include a hole 82. The fastening element 90 may be a screw or bolt, for example, having threads. As shown, the fastening element 90 may extend through a hole in the root end flange 92 and into a hole 82 to fasten the connecting element to the root end flange 92. The hole 82 may include a corresponding thread for engaging with the fastening element 90.

[0049] Figure 6 It shows Figure 5 The connecting element 60 and the downlead 50 are along, as shown in the figure Figure 5 The cross-sectional views of lines 100 and 102 indicated in the figure. Figure 6 a) shows a cross-sectional view along line 100. Figure 6 b) shows a cross-sectional view along line 102. According to conventional lightning down conductors, down conductor 50 includes a conductive element 53 and an insulating sheath 55 covering the conductive element 50. Figure 6 As shown in a), the insulating sheath 55 has been removed from a portion of the downlead to form a stripped portion 52 housed in the first conductor portion 66. Although not specifically shown, the first conductor portion 66 may be electrically connected to the conductive portion 53 of the downlead, for example, the first conductor portion 66 may be crimped to engage with the conductive portion 53.

[0050] Still Figure 6 The image shown is perpendicular to... Figure 5 The radial axis 72 of the conductor portion axis 70 shown. The first conductor portion 66 of the connecting element 60 has a first material thickness T1 along the radial axis 72. The second conductor portion 68 has a second material thickness T2 along the radial axis. As shown, the second material thickness T2 may be less than the first material thickness T1. Alternatively, the second material thickness T2 may be greater than the first material thickness T1, or the second material thickness T2 and the first material thickness T1 may be the same.

[0051] By crimping the first conductor portion 66, the first conductor portion 66 can be secured to the stripped portion 52 of the downlead 50. For example, along the radial axis 72, the first conductor portion 66 can be secured by reducing the first cross-sectional distance D11. Alternatively, the first conductor portion 66 can be secured by reducing the second cross-sectional distance D12. The first conductor portion 66 can be crimped such that the first cross-sectional distance D11 is shorter than the second cross-sectional distance D12. As shown, the second cross-sectional distance D12 can be perpendicular to the first cross-sectional distance D11.

[0052] The second conductor portion 68 can be secured to the insulation portion 54 of the downlead 50 by crimping it. For example, along the radial axis 72 as shown, the second conductor portion 68 can be secured by reducing the first cross-sectional distance D21. Alternatively, the second conductor portion 68 can be secured by reducing the second cross-sectional distance D22. The second conductor portion 68 can be crimped such that the first cross-sectional distance D21 is shorter than the second cross-sectional distance D22. As shown, the second cross-sectional distance D22 can be perpendicular to the first cross-sectional distance D21.

[0053] Figure 6 The internal cross-sectional distances d1 and d2 of the first conductor portion 66 and the second conductor portion 68 are also shown. The first conductor portion 66 has a first internal cross-sectional distance d1, which allows the first conductor portion 66 to accommodate the stripped portion 52 of the down conductor 50. The second conductor portion 68 has a second internal cross-sectional distance d2, which allows the second conductor portion to accommodate the insulation portion 54 of the down conductor 50.

[0054] Figure 7a , 7b Figures 7c and 7d show longitudinal cross-sectional views of an exemplary connecting element 60. The connecting element 60 includes a root end portion 62 and a conductor portion 64, the conductor portion 64 including a first conductor portion 66 and a second conductor portion 68 having a conductor portion axis 70. The connecting element 60 includes a fastening section 80 at the root end portion 62 for connection with a fastening element 90 (e.g., as shown in Figures 7c and 7d). Figure 7d (As shown) engagement to secure the connecting element 60 to the root region 30 of the wind turbine blade. Figures 7a-7d The exemplary connecting element 60 shows different material thicknesses (e.g., as shown in relation to...) Figure 6 Examples of T1 and T2 mentioned above.

[0055] Figure 7bIt is also shown that the connecting element 60 may have an internal separation structure 84 that separates the fastening element 90 from the stripped portion 52 of the downlead wire, for example, when inserted into the hole of the fastening section 80.

[0056] also, Figure 7d The connecting element 60 is shown to be fastened to the root end region 30 by a fastening element 90, which may be a screw or bolt, engaging with a hole 82 in the fastening section 80.

[0057] Such as Figure 7a and 7b As illustrated, the connecting element 60 can provide a gap between the edge of the end of the insulating portion of the downlead 54 and the interior of the conductor portion 64 of the connecting element. The gap can provide a guiding surface for guiding the stripped portion 52 into the first conductive portion 66.

[0058] Figure 8 A flowchart of an exemplary method 200 is shown, which is used to connect the downlead of the lightning protection system of a wind turbine blade to the root region of the wind turbine blade, for example, to the root end flange of the wind turbine blade.

[0059] Method 200 includes providing a connecting element 202, such as a connecting element illustrated and described in the previous figures. The connecting element includes a root end portion and a conductor portion, the conductor portion including a first conductor portion and a second conductor portion.

[0060] Method 200 includes removing 204 insulation sheath from a portion of the end of the down conductor to provide a stripped portion and an insulation portion of the down conductor.

[0061] Method 200 includes inserting the end of a downlead wire 206 into a conductor portion of a connecting element such that a stripped portion is received by a first conductor portion and an insulating portion is received by a second conductor portion of the connecting element.

[0062] Method 200 includes securing a second conductor portion 208 to an insulating portion. For example, the second conductor portion can be secured 208, for example, around the insulating portion of a down conductor, by crimping the second conductor portion. Crimping the second conductor portion may include reducing one or more cross-sectional distances of the second conductor portion.

[0063] Optionally, method 200 may include securing the first conductor portion 210 to the stripped portion of the downlead. For example, the first conductor portion may be secured 210, for example, around the stripped portion of the downlead, by crimping the first conductor portion. Crimping the first conductor portion may include reducing one or more cross-sectional distances of the first conductor portion.

[0064] The tightening 208 of the second conductor portion can be performed before or after the tightening 210 of the first conductor portion. Alternatively, the tightening 208 of the second conductor portion can be performed together with the tightening 210 of the first conductor portion, for example, the tightening 208 of the second conductor portion can be performed simultaneously with the tightening 210 of the first conductor portion.

[0065] Optionally, method 200 may include surrounding 212 with a second insulating sheath (such as a shrinkable tube or heat-shrinkable tube) of the conductor portion of the connecting element. The conductor portion of 212 surrounded by the second insulating sheath may be provided to isolate the connecting element from the environment, for example, to protect the connecting element and / or its connection to the downlead from water or other substances.

[0066] Method 200 includes fastening 214 of the root end portion of a connecting element to the root region of a wind turbine blade, such as fastening it to a root end flange of a wind turbine blade.

[0067] The invention has been described with reference to preferred embodiments. However, the scope of the invention is not limited to the illustrated embodiments, and changes and modifications can be made without departing from the scope of the invention.

[0068] Reference List

[0069] 2. Wind turbine

[0070] 4 towers

[0071] 6. Cabin

[0072] 8 hubs

[0073] 10 blades

[0074] 14. Leaf tips

[0075] 15 distal end

[0076] 16. Leaf base

[0077] 17. Root end

[0078] 18. Predestined Fate

[0079] 20 trailing edge

[0080] 24 First blade shell section (pressure side)

[0081] 26 Second blade shell section (suction side)

[0082] 28. Joint line / glued joint

[0083] 30 Root region

[0084] 32 Transition Zone

[0085] 34. Airfoil area

[0086] 40 Shoulders

[0087] 42 Lightning Protection System

[0088] 50 down conductor

[0089] 52 (Stripped section of the down conductor)

[0090] 53 Conductive Components

[0091] 54. Insulation portion (of the down conductor)

[0092] 55 Insulating Sheath

[0093] 56. End of the down conductor

[0094] 60 Connecting elements

[0095] 62. Root end portion

[0096] 64 Conductor section

[0097] 66 First Conductor Section

[0098] 68 Second conductor section

[0099] 70 Conductor section axis

[0100] 72 Radial axis

[0101] 80 Fastening Section

[0102] 82 (Hole in the fastening section)

[0103] 84 Internal Separation Structure

[0104] 90 Fastening components

[0105] 92 Root end flange

[0106] 200 methods

[0107] 202 Provides connecting elements

[0108] 204 Remove the insulating sheath

[0109] 206 Insert the end of the downlead wire

[0110] 208 Secure the second conductor section

[0111] 210 Secure the first conductor section

[0112] 212 Surrounding conductor portion

[0113] 214 Secure the root end portion

[0114] T1 First material thickness

[0115] T2 Second material thickness

[0116] D11 First cross-sectional distance of the first conductor portion

[0117] D12 Distance between the second cross-section of the first conductor portion

[0118] D21 The first cross-sectional distance of the second conductor section

[0119] D22 The distance between the second cross sections of the second conductor portion.

Claims

1. A wind turbine blade comprising a root region, an airfoil region with a tip, a pressure side, a suction side, and a chord extending between a leading edge and a trailing edge, the wind turbine blade further comprising a lightning protection system, the lightning protection system comprising a downleader extending from the root region toward the tip and a connecting element connecting the downleader to the root region, the connecting element comprising: - The root end portion, which is mechanically and electrically connected to the root region of the wind turbine blade; as well as - A conductor portion comprising a first conductor portion and a second conductor portion, wherein the first conductor portion accommodates and is electrically connected to a stripped portion of the down conductor, and the second conductor portion accommodates and is mechanically connected to an insulating portion of the down conductor, the conductor portion axis of the conductor portion being substantially coaxial with the longitudinal direction of the down conductor, and wherein the first conductor portion and the second conductor portion are substantially cylindrical along the conductor portion axis.

2. The wind turbine blade according to claim 1, wherein the first conductor portion and the second conductor portion are integrally formed.

3. The wind turbine blade according to claim 1 or 2, wherein the first conductor portion has a first material thickness along a radial axis perpendicular to the axis of the conductor portion, and the second conductor portion has a second material thickness parallel to the radial axis.

4. The wind turbine blade according to claim 3, wherein the thickness of the second material is greater than the thickness of the first material.

5. The wind turbine blade according to claim 3, wherein the thickness of the second material is less than the thickness of the first material.

6. The wind turbine blade according to claim 3, wherein the thickness of the second material is the same as the thickness of the first material.

7. The wind turbine blade according to claim 1 or 2, wherein the connecting element is made of metal.

8. The wind turbine blade of claim 1 or 2, wherein the root end portion includes a fastening section that engages with a fastening element to fasten the connecting element to the root region of the wind turbine blade.

9. The wind turbine blade of claim 8, wherein the fastening section includes a hole for receiving the fastening element, wherein the hole is internally threaded to engage with the opposing thread of the fastening element.

10. The wind turbine blade of claim 7, wherein the connecting element is made of copper.

11. A method for connecting a down conductor of a lightning protection system for a wind turbine blade to a root region of the wind turbine blade, the wind turbine blade including a root region, an airfoil region with a tip, a pressure side, a suction side, and a chord extending between a leading edge and a trailing edge, the down conductor extending from the root region toward the tip and including a conductive element and an insulating sheath covering the conductive element, the method comprising: - A connecting element is provided, the connecting element comprising a root end portion and a conductor portion, the conductor portion comprising a first conductor portion and a second conductor portion, the first conductor portion and the second conductor portion being substantially cylindrical along the conductor portion axis of the conductor portion. - Remove the insulating sheath from a portion of the end of the down conductor to provide a stripped and insulated portion of the down conductor; - Insert the end of the downlead into the conductor portion of the connecting element such that the stripped portion is received by the first conductor portion and the insulating portion is received by the second conductor portion of the connecting element, and such that the longitudinal direction of the downlead is substantially coaxial with the axis of the conductor portion; - Secure the second conductor portion to the insulating portion; as well as - Secure the root end portion of the connecting element to the root region of the wind turbine blade.

12. The method of claim 11, wherein securing the second conductor portion to the insulating portion comprises crimping the second conductor portion.

13. The method according to any one of claims 11-12, further comprising securing the first conductor portion to the stripped portion of the downlead.

14. The method of claim 13, wherein securing the first conductor portion to the stripped portion comprises crimping the first conductor portion.

15. The method according to any one of claims 11-12, wherein the method further comprises surrounding the conductor portion of the connecting element with a second insulating sheath.

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