Wind power blade root downlead connecting structure and connecting method

Abstract

A wind power blade root downlead connecting structure comprises a flange plate and a downlead and further comprises a connecting piece, and the connecting piece comprises at least one connecting part connected with the flange plate in a fastened mode. The connecting part is also connected with a crimping end, an insulating layer at one end of the downlead is crimped on the crimping end, an insulating layer at the other end of the downlead is crimped with a conductive fastener, the wire core is connected with the conductive fastener, and the conductive fastener is conductively and tightly connected with the flange plate; the downlead section between the crimping end and the conductive fastener is in a free state. According to the down lead connecting structure and method, the connecting piece is used for bearing the pulling force in the rotating process of the draught fan, the down lead of the blade root part is in a free state and is not pulled after being connected, and the phenomenon that the down lead of the blade root part is broken due to rotation or swing of the draught fan is avoided.

Description

Technical Field

[0001] The invention relates to the field of wind power lightning protection equipment, and in particular to a wind power blade root downconductor connection structure and a connection method. Background Art

[0002] As a renewable and clean energy, wind power generation has attracted more and more attention at home and abroad. With the development of wind power technology, the height of wind turbines has been increasing with the increase of hub height and impeller diameter, and the risk of wind turbines being struck by lightning has also increased. Among them, the economic losses caused by the maintenance of wind turbine components damaged by lightning and the reduction of power generation during downtime are very serious. Therefore, this puts higher requirements on the lightning protection technology of wind turbine blades. After the existing lightning protection down conductor is led out from the starting position of the blade web to the blade root, it is directly straightened and fixed on the metal flange of the blade root. The straightened down conductor is bonded to the inner wall of the blade through structural bonding or other glue, and is fixed on the surface of the down conductor by hand-pasting glass fiber cloth or covering with glass fiber reinforced plastic pressure plate. The down conductor is connected to the flange through a single-hole copper nose. There are two ways to connect the single-hole copper nose to the flange. One is to directly punch a bolt hole to connect to the flange; the other is to weld a connecting piece on the flange to connect to the copper nose. Both of these connection methods have large contact resistance, and the reliability of the second method is poorer than the first. In the prior art, the lightning protection down conductor is fixed in a straight line from the starting position of the blade web to the blade root flange, and the down conductor is in a taut state. During the operation of the wind turbine, the blades will vibrate, and the down conductor will deform with the vibration of the blades. If the wire is in a taut state, it will be torn off, and the copper nose connected to the flange will also be pulled off during the deformation process, which will cause the lightning protection system of the blade to fail, causing the wind turbine to be damaged by lightning.

[0003] Through searching, technical documents related to mobile post stations or prefabricated public toilets have been disclosed in the prior art. For example, the invention patent publication document with the publication number "CN103352808A" and the name "A method for connecting a lightning conductor in a wind turbine hub and a lightning conductor system" is disclosed. A method for connecting a lightning conductor in a wind turbine hub and a lightning conductor system are disclosed, and the wind turbine hub lightning conductor is divided into two parts, one of which is a lightning conductor connection mounting plate with a rigid structure, and the other is a soft lightning conductor with a flexible structure. The semi-rigid composite wind turbine hub lightning conductor formed by the combination of the lightning conductor connection mounting plate and the soft lightning conductor, and then the semi-rigid composite wind turbine hub lightning conductor is installed on the manhole cover plate at the blade end and the hub bracket respectively to form a wind turbine hub lightning conductor connection system. The comparative document uses a flexible lightning conductor to release the torque between the blade end and the hub end to avoid breakage. This connection structure is not suitable for the connection of the down conductor at the root of the blade.

[0004] For example, the invention patent publication document with the publication number of "CN112483335A" and the name of "A lightning protection component for the root of a wind turbine blade and its installation method" discloses a lightning protection component for the root of a wind turbine blade and its installation method. The lightning protection component includes a lightning protection ring, a cap-shaped glass fiber reinforced plastic washer, a connecting ear and a carbon brush. The lightning protection ring is connected to the connecting ear and the carbon brush respectively. The end of the connecting ear away from the lightning protection ring is connected to the copper wire. The carbon brush is connected to the blade hub. The copper wire conducts lightning to the lightning protection ring through the connecting ear. The lightning received by the lightning protection ring is conducted to the blade hub through the carbon brush. The lower end face of the cap-shaped glass fiber reinforced plastic washer is bonded to the root of the blade. The cap-shaped glass fiber reinforced plastic washer is assembled from two completely identical half-cap-shaped glass fiber reinforced plastic washers. The lightning protection ring is welded from two semi-circular rings. Bolts are sequentially passed through the semi-circular ring and the semi-cap-shaped glass fiber reinforced plastic washer and then threadedly connected with nuts to connect the semi-circular ring and the semi-cap-shaped glass fiber reinforced plastic washer. This comparative document prevents the lightning protection component from falling off by connecting the stainless steel lightning protection ring to the blade root, but does not involve the fixing structure and method of the lightning protection wire at the blade root.

[0005] For example, the invention patent publication document with the publication number "CN115681027A" and the name "A root end fixing structure and fixing method for a lightning conductor for a wind turbine blade" is disclosed. A root end fixing structure and fixing method for a lightning conductor for a wind turbine blade is disclosed, including a conductor fixed on the blade, the conductor is curved at the starting point of the leading edge web and the starting point of the trailing edge web on the blade, the outer side of the conductor is fixed to the blade by hand-laid glass fiber cloth and a glass fiber reinforced plastic pressure plate, the hand-laid glass fiber cloth is disconnected at the crest position of the bending of the conductor; the conductor is connected to the flange through a copper nose after passing through the baffle position; the conductor is bent and wired when fixed at the root of the blade, and a small section of movable margin is reserved to prevent the conductor from being tightened during the later deformation process. This comparative document takes into account the root end fixing structure of the lightning conductor, and focuses on eliminating the mechanical stress of the root end fixation. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a wind turbine blade root down conductor connection structure, comprising a flange and a down conductor, and also comprising a connecting piece, wherein the connecting piece comprises at least one connecting portion that is fastened to the flange; the connecting portion is also connected to a crimping end, the insulating layer at one end of the down conductor is crimped on the crimping end, the insulating layer at the other end is crimped to a conductive fastener, and the wire core is connected to the conductive fastener, and the conductive fastener is conductively fastened to the flange; the down conductor section between the crimping end and the conductive fastener is in a free state.

[0007] Furthermore, the connecting portion of the connecting piece is symmetrically distributed relative to the crimping end.

[0008] Furthermore, the connecting piece is a cross insulating sleeve, the middle sleeve of the cross insulating sleeve is crimped to the insulating layer of the down conductor, and the sleeves on both sides are fastened and connected by elastic insulating wires and flanges.

[0009] Alternatively, the connector comprises a middle insulating sleeve for crimping the insulation layer of the down conductor, and symmetrical connecting arms integrally formed on both sides of the middle insulating sleeve, one end of the connecting arm being tightly connected to the flange.

[0010] Furthermore, the conductive fastener has a fitting portion connected to the surface of the flange, and the fitting portion is conductively connected to the flange.

[0011] Furthermore, the fitting portion has at least two conductive connection ends connected to the flange.

[0012] Furthermore, the fitting portion is an arc-shaped conductive connector perpendicular to the down conductor, both ends of the arc-shaped conductive connector are bolted to the surface of the flange, and the middle portion is crimped to the core of the down conductor.

[0013] Furthermore, the fitting portion is a conductive connecting piece colinear with the axis of the down conductor, the conductive connecting piece has two or more through holes and is connected to the flange surface by bolts, and one end of the conductive connecting piece is crimped to the down conductor.

[0014] A method for connecting a down conductor at the root of a wind turbine blade is also proposed, which adopts the down conductor connection structure and specifically includes the following steps: Step S1, a certain length of the down conductor at the blade root is reserved and its insulation layer is respectively crimped to the crimping end of the connector and the conductive fastener, and the wire core is connected to the conductive fastener; Step S2, fixing the connecting part of the connecting piece to the flange; Step S3, fastening the conductive fastener and the flange at one end of the down conductor so that the down conductor between the crimping end and the conductive fastener is in a free state.

[0015] Furthermore, in the step S2, it specifically includes first drilling two or more through holes on the fitting part; then, according to the diameter of the down conductor, stripping one end of the down conductor and crimping it on the fitting part; and then fastening the fitting part to the flange by bolts engaging the through holes.

[0016] Compared with the prior art, the technical solution of the present application has the following beneficial effects: the down conductor connection structure and method proposed in the present invention utilize the connecting parts to withstand the tension during the rotation of the wind turbine, and the down conductor at the root of the blade is in a free state after connection and is not subject to tension, thereby preventing the down conductor at the root of the blade from breaking due to the rotation or swinging of the wind turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1: Schematic diagram of the basic structure of the down conductor connection structure; Figure 2 : Schematic diagram of down conductor connection structure; Figure 3 : Figure 2 Partial magnified image; Figure 4 : Schematic diagram of down conductor connection structure; Figure 5 : Schematic diagram of the conductive connector structure. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] A wind turbine blade root down conductor connection structure comprises a flange 1 and a down conductor 2, and also comprises a connector 3, wherein the connector comprises at least one connecting portion 31 which is fastened to the flange 1; the connecting portion 31 is also connected to a crimping end 32, an insulating layer at one end of the down conductor 2 is crimped to the crimping end 32, and an insulating layer at the other end is crimped to a conductive fastener 4, and the wire core is connected to the conductive fastener 4, and the conductive fastener 4 is conductively fastened to the flange 1; a section of the down conductor 2 between the crimping end 32 and the conductive fastener 4 is in a free state.

[0020] Figure 1 The reference schematic diagram of the connection structure in this embodiment is shown. The two ends of the insulation layer of the down conductor 2 between the connector 3 and the flange 1 are respectively crimped by the crimping end 32 of the connector 3 and the conductive fastener 4, and the down conductor 2 in this section is in a free state. Since the connecting portion 31 of the connector 3 is tightly connected to the flange 1, when the blade rotates or swings, the tension is borne by the connecting portion 31 of the connector 3, and the down conductor 2 does not bear the tension and is always in a free state. Therefore, the down conductor 2 under the connection structure will not break and fail due to the tension, thereby improving reliability. The connector 3 is preferably supported by insulating material as a whole, and its crimping end 32 and the connecting portion 31 can be integrally formed or a split structure.

[0021] In a more preferred embodiment, see Figure 2 The connecting portion 31 of the connecting member 3 is symmetrically distributed relative to the crimping end 32. The symmetrically distributed connecting portion 31 can evenly bear the above-mentioned pulling force, further improving reliability.

[0022] A possible implementation can refer to Figure 2The connector 3 is a cross insulating sleeve 33, the middle sleeve of the cross insulating sleeve 33 is crimped with the insulation layer of the down conductor 2, and the sleeves on both sides are fastened and connected to the flange 1 through elastic insulating wires 331. The elastic insulating wires 331 are symmetrically distributed, and in this embodiment, one is distributed on each side of the sleeve relative to the middle, and the ends are connected to the flange 1 through rivets. The elastic insulating wires 331 can withstand tension well to ensure that the down conductor 2 is not subjected to tension.

[0023] Another possible implementation can be found in Figure 4 , the crimping end 32 and the connecting portion 31 in the connector 3 under this embodiment are an integral structure. The connector 3 includes a middle insulating sleeve 34 for crimping the insulation layer of the down conductor 2, and symmetrical connecting arms 35 integrally formed on both sides of the middle insulating sleeve 34, and one end of the connecting arm 35 is fastened to the flange 1. It can be understood that after the connecting arm 35 is fastened to the flange 1 by bolts, it is used to withstand tension, prevent the down conductor 2 from being subjected to tension, and ensure that it can maintain a free state.

[0024] Based on the above-mentioned embodiment, in the connection between the end of the down conductor 2 and the flange 1, it is also necessary to consider the structural reliability and the conductive drainage capacity. The common copper nose is connected to the flange 1 after crimping, the impedance is large, and the connection is not very stable. Based on this, the conductive fastener 4 has a fitting portion connected to the surface of the flange 1, and the fitting portion is conductively connected to the flange 1. The fitting portion has at least two conductive connection ends connected to the flange 1. The fitting portion will be tightly fitted and connected to the surface of the flange 1, so that the drainage conductive connection between the down conductor 2 and the flange 1 has a larger conductive connection area, reducing the impedance and improving the drainage capacity. Two or more conductive connection ends can make the drainage between the down conductor 2 and the flange 1 present a parallel relationship, while increasing the structural stability, further improving its drainage capacity.

[0025] In a more preferred embodiment, see Figure 5 , the fitting part is an arc-shaped conductive connector 41 perpendicular to the down conductor 2, the two ends of the arc-shaped conductive connector 41 are bolted to the surface of the flange 1, and the middle part is crimped to the wire core of the down conductor 2. The arc-shaped conductive connector 41 optimizes the fixing method of the blade root down conductor, reduces the possibility of the root of the conductive connector being broken due to mechanical stress caused by deformation of the blade root down conductor in the later stage, improves the reliability of the connection between the down conductor and the flange 1, and reduces the risk of lightning protection failure. In addition, the arc-shaped conductive connector 41 can fit tightly with the flange 1, reduces the contact resistance connected to the flange 1, improves the drainage capacity of the down conductor 2 and the flange 1, and reduces the risk of lightning protection failure.

[0026] Another embodiment of the conductive connector can be seen in Figure 3The fitting part is a conductive connecting piece 42 which is colinear with the axis of the down conductor 2. The conductive connecting piece 42 has two or more through holes and is bolted to the surface of the flange 1 by bolts. One end of the conductive connecting piece 42 is crimped to the down conductor 2. The down conductor 1 is crimped to the conductive connecting piece 42, and the conductive connecting piece 42 is in parallel mode, which reduces the contact resistance with the flange, enhances the conductivity of the down conductor 2 and the flange 1, improves the drainage capacity, and reduces the risk of lightning protection failure.

[0027] The present embodiment also relates to a down conductor connection method, and specifically comprises the following steps: Step S1, reserve a certain length of the down conductor 2 at the blade root and crimp its insulation layer to the crimping end 32 of the connector 3 and the conductive fastener 4 respectively, and connect the wire core to the conductive fastener 4; Step S2, fixing the connecting portion 31 of the connecting member 3 to the flange 1; Step S3, fastening the conductive fastener 4 at one end of the down conductor 2 to the flange 1 so that the down conductor 2 between the crimping end 32 and the conductive fastener 4 is in a free state.

[0028] Furthermore, in the step S2, it specifically includes first drilling two or more through holes on the fitting part; then, according to the diameter of the down conductor 2, stripping one end of the down conductor 2 and crimping it on the fitting part; and then fastening the fitting part to the flange 1 by bolts engaging the through holes.

[0029] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0030] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wind turbine blade root down conductor connection structure, comprising a flange (1) and a down conductor (2), characterized in that: It also includes a connecting piece (3), the connecting piece including at least one connecting portion (31) fastened to the flange (1); the connecting portion (31) is also connected to a crimping end (32); the insulation layer at one end of the down conductor (2) is crimped onto the crimping end (32), the insulation layer at the other end is crimped onto a conductive fastener (4), and the wire core is connected to the conductive fastener (4); the conductive fastener (4) and the flange (1) are conductively fastened; the section of the down conductor (2) between the crimping end (32) and the conductive fastener (4) is in a free state.

2. The wind turbine blade root down conductor connection structure according to claim 1, characterized in that: The connecting portion (31) of the connecting piece (3) is symmetrically distributed relative to the crimping end (32).

3. The wind turbine blade root down conductor connection structure according to claim 2, characterized in that: The connecting piece (3) is a cross-shaped insulating sleeve (33), the middle sleeve of the cross-shaped insulating sleeve (33) is crimped to the insulating layer of the down conductor (2), and the sleeves on both sides are fastened and connected via elastic insulating wires (331) and flanges (1).

4. The wind turbine blade root down conductor connection structure according to claim 2, characterized in that: The connecting piece (3) comprises a middle insulating sleeve (34) for crimping the insulating layer of the down conductor (2), and symmetrical connecting arms (35) integrally formed on both sides of the middle insulating sleeve (34); one end of the connecting arm (35) is tightly connected to the flange (1).

5. The wind turbine blade root down conductor connection structure according to claim 1, characterized in that: The conductive fastener (4) comprises a fitting portion connected to the surface of the flange (1), and the fitting portion and the flange (1) are conductively connected.

6. The wind turbine blade root down conductor connection structure according to claim 5, characterized in that: The fitting portion has at least two conductive connection ends connected to the flange (1).

7. The wind turbine blade root down conductor connection structure according to claim 6, characterized in that: The fitting portion is an arc-shaped conductive connector (41) perpendicular to the down conductor (2), with both ends of the arc-shaped conductive connector (41) being bolted to the surface of the flange (1) and the middle portion being crimped to the core of the down conductor (2).

8. The wind turbine blade root down conductor connection structure according to claim 6, characterized in that: The fitting portion is a conductive connecting piece (42) colinear with the axis of the down conductor (2), the conductive connecting piece (42) having two or more through holes and connected to the surface of the flange (1) via bolts, and one end of the conductive connecting piece (42) is crimped to the down conductor (2).

9. A method for connecting a down conductor at the root of a wind turbine blade, characterized in that: The down conductor connection structure as claimed in claim 5 is adopted, and specifically comprises the following steps: Step S1, a certain length of the down conductor (2) at the blade root is reserved and its insulation layer is respectively crimped to the crimping end (32) of the connector (3) and the conductive fastener (4), and the wire core is connected to the conductive fastener (4); Step S2, fixing the connecting portion (31) of the connecting member (3) to the flange (1); Step S3, fastening the conductive fastener (4) at one end of the down conductor (2) and the flange (1) so that the down conductor (2) between the crimping end (32) and the conductive fastener (4) is in a free state.

10. The wind turbine blade root down conductor connection method according to claim 9, characterized in that: In the step S2, it specifically includes first drilling two or more through holes on the fitting part; then, according to the diameter of the down conductor (2), stripping one end of the down conductor (2) and crimping it on the fitting part; and then fastening the fitting part to the flange (1) by bolts engaging the through holes.

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