Transformer coil winding method

Abstract

The invention provides a transformer coil winding method, and belongs to the technical field of material processing. The technical means of annealing the copper foil to reduce the hardness before the low-voltage coil is wound is adopted, so that the plasticity of the copper strip is higher when the coil is wound, the size of the low-voltage coil is better guaranteed, the design requirement is met, and the overall press-fitting and curing process of the coil is replaced. The hardness of the copper strip is reduced through continuous annealing, it is guaranteed that the V-shaped guide wheel on the low-voltage coil foil winding machine can remove edge burrs, the coil winding difficulty is reduced, especially the size is guaranteed, the coil size can be effectively guaranteed, and risks caused by coil press-fitting curing can be reduced or avoided. According to the coil, the use amount of copper strips can be reduced, the cost can be reduced, the coil winding efficiency is improved, the beating action in the winding process is reduced, and the state that the coil is naturally stressed after being wound due to the fact that the whole coil is pressed and solidified is omitted, so that the sudden short circuit resistance of the coil is improved.

Description

Technical Field

[0001] The invention relates to the technical field of material processing, and in particular to a transformer coil winding method. Background Art

[0002] With the development of the power system, the power supply range of the transformer is constantly expanding. Since the transformer plays the role of converting voltage and transmitting electric energy in the entire power system, the quality of the transformer directly determines the reliability of the power supply and the operating life of the entire power system. In addition, with the State Grid's increasing requirements for the transformer's ability to resist sudden short circuits, the manufacturing requirements for transformers have also increased. As a traditional manufacturing industry, the transformer industry has a high degree of manual participation in each manufacturing unit. The coil is the "heart" of the transformer, and the quality of the coil is a decisive factor in the overall quality, resistance to sudden short circuits and life of the transformer.

[0003] As a traditional manufacturing industry, transformer manufacturing has a unified manufacturing process. The main process flow in the coil stage is 1. Insulation production, 2. Low-voltage coil winding, 3. High-voltage coil winding, 4. Coil inspection, and 5. Overall coil pressing and curing.

[0004] To improve efficiency, most transformer low-voltage coils are wound with copper tape. However, using copper tape to wind low-voltage coils can easily cause the low-voltage coils to be too large in size. The larger the coil, the wider and thicker the copper tape, the greater the rigidity of the copper tape, and the more difficult it is to control the coil winding size. Therefore, winding a high-voltage coil on the basis of a low-voltage coil will also cause the coil size to be too large, which results in an increase in the use of copper materials. In order to meet assembly requirements, it is also necessary to add a press-fitting and curing process to meet the requirements.

[0005] Moreover, transformers with quality problems are mostly low-voltage coils. Low-voltage coil failures are mostly caused by burrs on the edges of copper strips during the manufacturing and transportation processes, copper strips with high hardness causing copper chips to fall into the coils during cutting, etc. The overall press-fitting and curing of the coils destroys the natural stress state of the coils after winding (press-fitting and curing refers to placing the coils in a special tooling and applying external force downward to deform them to the designed size), thereby reducing the coils' ability to resist sudden short circuits.

[0006] Therefore, the prior art lacks a transformer coil winding method with better effect. Summary of the invention

[0007] The object of the present invention is to provide a transformer coil winding method, which can reduce the quality risks of the coil and reduce the cost, and avoid external forces (secondary damage caused by press-fitting and curing) from destroying the overall natural stress state of the coil from the source, thereby improving the ability of the coil itself to resist sudden short circuits.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0009] The present invention provides a transformer coil winding method, comprising the following steps:

[0010] S1, annealing the copper foil to obtain annealed copper foil;

[0011] S2. Use annealed copper foil to wind low-voltage coils.

[0012] Preferably, the step S1 also includes insulation production.

[0013] Preferably, the step S2 further includes the steps of high voltage coil winding and coil inspection.

[0014] Preferably, the annealing treatment is a secondary annealing treatment.

[0015] Preferably, the temperature of the secondary annealing treatment is 420-450°C.

[0016] Preferably, the secondary annealing treatment is carried out for 3 hours.

[0017] Preferably, the copper foil has a thickness of 0.8-1.6 mm.

[0018] Technical effects and advantages of the present invention:

[0019] The present invention adopts the technical means of annealing the copper foil to reduce the hardness before the low-voltage coil is wound, so that the copper strip has stronger plasticity when the coil is wound, so as to better ensure the size of the low-voltage coil and meet the design requirements, so as to replace the overall press-fitting and curing process of the coil. Continuous annealing reduces the hardness of the copper strip, ensures that the V-shaped guide wheel on the low-voltage coil foil winding machine can remove the burrs on the edge, reduces the difficulty of coil winding, especially the size guarantee, can effectively ensure the coil size and reduce or avoid the risks brought by the press-fitting and curing of the coil (omit the coil press-fitting process, reduce the secondary damage to the coil by external force, make the coil structure more stable, and also reduce insulation damage). More intuitively, it can reduce the amount of copper strip used, reduce costs, increase the coil winding efficiency, reduce the knocking action during the winding process, and avoid quality accidents or quality problems caused by the damage of the interlayer insulation of the low-voltage coil (piercing of the copper strip burrs). In addition, the natural stress state of the coil winding is destroyed by eliminating the need for the overall press-fitting and curing of the coil (press-fitting and curing refers to placing the coil in a special tooling and applying external force downward to deform it to the designed size), thereby improving the coil's ability to resist sudden short circuits. DETAILED DESCRIPTION

[0020] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0021] Example 1

[0022] Carry out the following processes:

[0023] 1. Insulation production

[0024] 2. Secondary annealing of copper foil (place the copper strip in the annealing furnace body - place the furnace body in the cranial cavity, close the door and evacuate for 30 minutes, let it stand for 20 minutes (observe whether the vacuum gauge rises to determine whether there is a leak, and proceed to the next step only if there is no leak) - inject protective gas (argon, nitrogen, carbon dioxide) 0.2Kpa - heat to 420-450℃ - keep warm for 3h - end the insulation - cool down the furnace to 300℃ - take out the furnace body (cool to about 50℃ with water circulation) - open the furnace body. Check whether the copper strip is oxidized after annealing).

[0025] 3. Low voltage coil winding

[0026] 4. High voltage coil winding

[0027] 5. Coil inspection.

[0028] Comparative Example 1

[0029] The process in Example 1 is replaced by:

[0030] 1. Insulation production

[0031] 2. Low voltage coil winding

[0032] 3. High voltage coil winding

[0033] 4. Coil inspection

[0034] 5. The coil is pressed and cured as a whole (the coil pressing and curing temperature is 160°C and kept warm for 3.5 hours).

[0035] The performance of the product coils provided in Example 1 and Comparative Example 1 was tested respectively, and the results are shown in Table 1 below:

[0036] Table 1 Product coil performance test results

[0037]

[0038]

[0039] The results show that the existing process destroys the natural stress state of the coil after winding, thereby reducing the ability of the coil itself to resist sudden short circuits, while the coil product provided by the present invention has better performance.

[0040] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A transformer coil winding method, characterized in that: The following steps are involved: S1, annealing the copper foil to obtain annealed copper foil; S2. Use annealed copper foil to wind low-voltage coils.

2. The transformer coil winding method according to claim 1, characterized in that: The step S1 also includes performing insulation production.

3. The transformer coil winding method according to claim 1, characterized in that: The step S2 also includes the steps of high voltage coil winding and coil inspection.

4. The transformer coil winding method according to claim 1, characterized in that: The annealing treatment is a secondary annealing treatment.

5. The transformer coil winding method according to claim 1, characterized in that: The temperature of the secondary annealing treatment is 420-450°C.

6. The transformer coil winding method according to claim 1, characterized in that: The secondary annealing treatment is carried out for 3 hours.

7. The transformer coil winding method according to claim 1, characterized in that: The thickness of the copper foil is 0.8-1.6 mm.

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