A welding method for transposed conductor

Abstract

The present invention provides a method for welding transposed conductors, which belongs to the technical field of transformers. The present invention provides a method for welding transposed conductors, wherein a first group of transposed conductors and a second group of transposed conductors are arranged side by side; a reference line is drawn in the straight position area after transposition, and the first group of transposed conductors determines a first overlap point on the right side of the reference line, and the second group of transposed conductors determines a second overlap point on the left side of the reference line; the conductors are cut off respectively; the conductor on the right side of the first overlap point is welded and fixed with the conductor on the left side of the second overlap point; the welded joint is polished, wiped, and bundled; each conductor of the first group of transposed conductors and the second group of transposed conductors is welded one by one in sequence; after the conductors are welded, the conductors are arranged in sequence according to the original sequence; and short-circuit measurement is performed on all the conductors in the transposed conductors. The present invention provides a method for welding transposed conductors, which improves welding efficiency, ensures welding quality, and avoids radial overheight of coil cakes.

Description

Technical Field

[0001] The invention belongs to the technical field of transformers, and in particular relates to a welding method for transposed conductors. Background Art

[0002] Transposed conductors are composed of multiple enameled flat copper wires combined into two rows with wide surfaces touching each other, with the same direction transposition made along the width on the top and bottom, and are continuously and tightly wrapped with multiple layers of insulating paper or heat shrinkable mesh. Transposed conductors are often used in the windings of large power transformers. The use of transposed conductors can greatly reduce load losses, reduce the temperature rise of winding hot spots, improve the mechanical strength of windings, make the structure more compact, improve space utilization, make the coils easy to process, and reduce manufacturing costs. The transposed conductors include a first column of conductors and a second column of conductors which are arranged in parallel. The first column of conductors is sequentially transposed to the second column of conductors from top to bottom, and the second column of conductors is sequentially transposed to the first column of conductors from bottom to top. In the process of conductor transposition, in order to reduce the height change of the transposed position, the conductors are generally transposed after being made into an S-bend, and the S-bend is used to form a transition area for the conductor transposition. The transposed conductors are limited in length, and the transposed conductors need to be extended during the winding process. The transposed conductors are generally connected and extended by welding. During the welding process, the two groups of transposed conductors are welded. The first group of transposed conductors is located on the side close to the iron core axis, that is, the bobbin side, and the second group of transposed conductors is located on the side away from the iron core axis, that is, the coil side. The second group of transposed conductors needs to be welded to the first group of transposed conductors. The compilation order and transposition position of the original first group of transposed conductors cannot be changed. Therefore, the selection of the welding point position, the method of restoring the conductors, and the length of each parallel conductor after welding are required to be kept consistent. The operation is very difficult. Summary of the invention

[0003] The object of the present invention is to provide a welding method for a transposed conductor, aiming to solve the problem that the welding operation of the transposed conductor is difficult.

[0004] To achieve the above object, the technical solution adopted by the present invention is: to provide a welding method for transposed conductors, comprising the following steps:

[0005] S1. The first group of transposed conductors and the second group of transposed conductors are arranged side by side, the welding parts of the first group of transposed conductors and the second group of transposed conductors are straightened, and the conductor transposed S-bends on the two groups of transposed conductors are aligned one by one;

[0006] S2, a reference line is drawn in the straight area of ​​the first group of transposed conductors and the second group of transposed conductors, a first overlap point is determined on the right side of the reference line for the first group of transposed conductors, and a second overlap point is determined on the left side of the reference line for the second group of transposed conductors, and the first overlap point and the second overlap point are respectively set on a row of conductors on the same side of the first group of transposed conductors and the second group of transposed conductors;

[0007] S3, cutting off the wire at the first bonding point and the wire at the second bonding point respectively;

[0008] S4, welding and fixing the wire on the right side of the first joint point and the wire on the left side of the second joint point;

[0009] S5. Grind and wipe the welded joints obtained after welding, and wrap and bundle the welded joints with insulating paper;

[0010] S6, repeating steps S2 to S5, welding each wire of the first group of transposed wires and the second group of transposed wires one by one in sequence, after welding 2 to 3 wires, arranging the welded wires on the second group of transposed wires in the original order, and temporarily fixing the free ends of the welded wires;

[0011] S7. After all the wires are welded, the wires are arranged in order according to the original sequence, the temporary fixation of the free ends of the wires is released, and the wires are arranged;

[0012] S8. Perform short-circuit measurement on all wires.

[0013] In a possible implementation, the distance between the starting positions of two upper and lower adjacent wire transpositions is defined as a transposition pitch S, and within a transposition pitch S, at most one welding position is selected.

[0014] In a possible implementation, before welding, a certain length needs to be reserved for both the first group of transposed conductors and the second group of transposed conductors. The number of conductors in a single group of transposed conductors is n, and the reserved length is at least n+1 transposition pitches S in length.

[0015] In a possible implementation, the reserved length is n+4 or n+5 transposition pitches S in length.

[0016] In a possible implementation, in step S2, before drawing the reference line, the transposed conductor is straightened and leveled using a straight wooden block.

[0017] In a possible implementation, in step S3, when the wire is cut, the surface paint film at the position where the wire is to be welded needs to be removed, and the removal process protects the coil and the wire in the unwelded area.

[0018] In a possible implementation, in step S4, the wire at the first overlapping point is overlapped with the wire at the second overlapping point, and the total length of the overlapping point is greater than or equal to 4 times the thickness a of the wire.

[0019] In a possible implementation, in step S5, after welding is completed, the thickness of a single wire at the welded joint is controlled to be between a+0.5 mm and a+1.0 mm.

[0020] In a possible implementation, in step S5, the insulating paper is Denison crepe paper, and is wrapped in a half-folded 2-layer wrapping method.

[0021] In a possible implementation, in step S6, the free end of the welded wire is temporarily fixed by bundling with a shrink band.

[0022] The beneficial effects of the welding method of a transposed conductor provided by the present invention are:

[0023] Compared with the prior art, during the welding process, the S-bends of the two groups of transposed conductors are aligned one by one, a reference line is drawn in the straight position area of ​​the S-bends, a first overlap point is determined on the right side of the reference line for the first group of transposed conductors, and a second overlap point is determined on the left side of the reference line for the second group of transposed conductors, the conductors are cut according to the first overlap point and the second overlap point, the cut conductors are welded, and after welding 2 to 3 conductors, the positions of the welded conductors are arranged, and the free ends of the welded conductors are temporarily fixed. After all the conductors are welded, the temporary fixation of the free ends of the conductors is released, the conductors are arranged, and finally the performance of the newly obtained transposed conductors is tested to confirm the welding quality. The operation is simple and quick, the welding efficiency is improved, the welding quality is guaranteed, and the radial overheight of the coil is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of the top view of the transposed conductor used in an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of a top view of a first group of transposed conductors and a second group of transposed conductors used in an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of defining a baseline for an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of determining a first overlapping point and a second overlapping point according to an embodiment of the present invention;

[0029] Figure 5 A schematic diagram of wire cutting according to an embodiment of the present invention;

[0030] Figure 6 It is a schematic diagram of the top view of the welding joint according to an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the main structure of a welding joint according to an embodiment of the present invention;

[0032] Figure 8 Schematic diagram of insulating paper wrapping according to an embodiment of the present invention;

[0033] Fig. 9 A schematic diagram of temporarily fixing the free end of a wire according to an embodiment of the present invention;

[0034] Fig.10 This is a schematic diagram of a welded transposed conductor obtained according to an embodiment of the present invention.

[0035] In the figure: 1, the first group of transposed conductors; 2, the second group of transposed conductors; 3, S-bend; 4, reference line; 5, first overlap point; 6, second overlap point; 7, welding joint; 8, insulating paper; 9, shrink tape; M, spool side; N, coil side. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] A specific implementation of a transposed conductor welding method provided by the present invention is now described, comprising the following steps:

[0038] S1. Please refer to Figure 1 , Figure 2 , two groups of transposed conductors are arranged side by side, the first group of transposed conductors 1 is located on the bobbin side M, the second group of transposed conductors 2 is located on the coil side N, the first group of transposed conductors 1 and the second group of transposed conductors 2 are arranged side by side, in order to reduce the increase in size after welding and eliminate quality risks, the welding parts of the first group of transposed conductors 1 and the second group of transposed conductors 2 need to be straightened, and the conductor transposition S-bends 3 on the two groups of transposed conductors are aligned one by one;

[0039] S2, please refer to Figures 2 to 4, select the welding position in the straight position area after the first row of wires are transposed, define the distance between the starting positions of the two adjacent wires transposed as the transposition pitch S, select at most one welding position within a transposition pitch S, use a straight wooden block to straighten the transposed wires, and to ensure that the welding position after welding is consistent with the shape of the original wire, each S-bend of the transposed wires reserved on the bobbin side M and the coil side N must be horizontally aligned before welding. Before welding, the first group of transposed wires 1 and the second group of transposed wires 2 need to reserve a certain length, and the wires of a single group of transposed wires The number is n, and the reserved length is at least n+1 transposition pitches S. To prevent welding errors and facilitate operation, the reserved length can be n+4 or n+5 transposition pitches S. A reference line 4 is defined in the straight area of ​​the first group of transposed conductors 1 and the second group of transposed conductors 2. The first group of transposed conductors 1 determines a first lap point 5 on the right side of the reference line 4, and the second group of transposed conductors 2 determines a second lap point 6 on the left side of the reference line 4. The first lap point 5 and the second lap point 6 are respectively arranged on a row of conductors on the same side of the first group of transposed conductors 1 and the second group of transposed conductors 2;

[0040] S3, please refer to Figure 5 , respectively cut off the wires at the first lap joint 5 and the wires at the second lap joint 6. When cutting the wires, use a paint remover or fine sandpaper to remove the paint film on the surface of the wires to be welded. Be careful not to damage the copper conductor. Use a clean white cloth to protect the coil and the wires in the unwelded area during the removal process;

[0041] S4, please refer to Figure 6 , Figure 7 , weld and fix the wire on the right side of the first lap joint 5 and the wire on the left side of the second lap joint 6, and overlap the wire at the first lap joint 5 and the wire at the second lap joint 6, and the total length of the overlap is greater than or equal to 4 times the thickness a of the wire;

[0042] S5, please refer to Figure 8 , grind and wipe the welded joint 7 obtained after welding. The welded joint 7 needs to be polished flat without sharp corners and burrs. Be careful not to damage the wire. After grinding, wipe it clean with alcohol. After welding, the thickness of a single wire at the welded joint 7 is controlled between a+0.5mm and a+1.0mm. Use insulating paper 8 to wrap and bundle the welded joint 7. The insulating paper 8 is Denison crepe paper, and is wrapped in a half-folded 2-layer wrapping method;

[0043] S6, please refer to Fig. 9Repeat steps S2 to S5 to weld each conductor of the first group of transposed conductors 1 and the second group of transposed conductors 2 one by one in sequence. After welding 2 to 3 conductors, arrange the welded conductors in sequence on the second group of transposed conductors 2 in the original order, and temporarily fix the free ends of the welded conductors, which can be temporarily fixed by bundling with a shrink band 9;

[0044] S7, please refer to Fig.10 After all the wires are welded, arrange the wires in the original order, release the temporary fixation of the free ends of the wires, and sort the wires;

[0045] S8. Use a 500V megger to perform short-circuit measurement on all wires in the transposition line. The insulation resistance between the wires must not be less than 0.1MΩ, and the wires must not be short-circuited or open-circuited.

[0046] The invention provides a method for welding transposed conductors. Compared with the prior art, in the welding process, the S-bends 3 of two groups of transposed conductors are aligned one by one, a reference line 4 is defined in the straight position area of ​​the S-bends 3, a first overlap point 5 is determined on the right side of the reference line 4 for the first group of transposed conductors 1, and a second overlap point 6 is determined on the left side of the reference line 4 for the second group of transposed conductors 2, the conductors are cut according to the first overlap point 5 and the second overlap point 6, the cut conductors are welded, and after welding 2 to 3 conductors, the positions of the welded conductors are arranged, and the free ends of the welded conductors are temporarily fixed, and after all the conductors are welded, the temporary fixation of the free ends of the conductors is released, the conductors are arranged, and finally the performance of the newly obtained transposed conductors is tested to confirm the welding quality, the operation is simple and quick, the welding efficiency is improved, the welding quality is guaranteed, and the radial overheight of the coil is avoided.

[0047] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A welding method for transposed conductors, characterized in that: The steps include: S1. The first group of transposed conductors and the second group of transposed conductors are arranged side by side, the welding parts of the first group of transposed conductors and the second group of transposed conductors are straightened, and the conductor transposed S-bends on the two groups of transposed conductors are aligned one by one; S2, a reference line is drawn in the straight area of ​​the first group of transposed conductors and the second group of transposed conductors, a first overlap point is determined on the right side of the reference line for the first group of transposed conductors, and a second overlap point is determined on the left side of the reference line for the second group of transposed conductors, and the first overlap point and the second overlap point are respectively set on a row of conductors on the same side of the first group of transposed conductors and the second group of transposed conductors; S3, cutting off the wire at the first bonding point and the wire at the second bonding point respectively; S4, welding and fixing the wire on the right side of the first joint point and the wire on the left side of the second joint point; S5. Grind and wipe the welded joints obtained after welding, and wrap and bundle the welded joints with insulating paper; S6, repeating steps S2 to S5, welding each wire of the first group of transposed wires and the second group of transposed wires one by one in sequence, after welding 2 to 3 wires, arranging the welded wires on the second group of transposed wires in the original order, and temporarily fixing the free ends of the welded wires; S7. After all the wires are welded, the wires are arranged in order according to the original sequence, the temporary fixation of the free ends of the wires is released, and the wires are arranged; S8. Perform short-circuit measurement on all wires.

2. A method for welding a transposed conductor according to claim 1, characterized in that: The distance between the starting positions of two adjacent conductors is defined as the transposition pitch S. Within a transposition pitch S, at most one welding position can be selected.

3. A welding method for transposed conductors as claimed in claim 2, characterized in that: Before welding, both the first group of transposed conductors and the second group of transposed conductors need to have a reserved length. The number of conductors in a single group of transposed conductors is n, and the reserved length is at least the length of n+1 transposition pitches S.

4. A method for welding a transposed conductor as claimed in claim 3, characterized in that: The reserved length is n+4 or n+5 transposition pitches S in length.

5. A method for welding a transposed conductor as claimed in claim 1, characterized in that: In step S2, before drawing the reference line, the transposed conductor is straightened and leveled using a straight wooden block.

6. A method for welding a transposed conductor as claimed in claim 1, characterized in that: In step S3, when the wire is cut, the surface paint film of the wire to be welded needs to be removed, and the removal process protects the coil and the wire in the unwelded area.

7. A method for welding a transposed conductor according to claim 1, characterized in that: In step S4, the wire at the first overlapping point is overlapped with the wire at the second overlapping point, and the total length of the overlapping point is greater than or equal to 4 times the thickness a of the wire.

8. A method for welding a transposed conductor as claimed in claim 1, characterized in that: In step S5, the thickness of the wire is a, and the thickness of a single wire at the welding joint after welding is completed is controlled between a+0.5mm and a+1.0mm.

9. A method for welding a transposed conductor as claimed in claim 1, characterized in that: In step S5, the insulating paper is Denison crepe paper, and is wrapped in a half-folded 2-layer wrapping method.

10. A method for welding transposed conductors as claimed in claim 1, characterized in that: In step S6, the free ends of the welded wires are temporarily fixed by bundling with shrink bands.

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