JP2835239B2 - Sheet winding transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet winding transformer for electric power having a sheet winding formed by superposing and winding a conductor sheet and an insulating sheet.

[0002]

2. Description of the Related Art A sheet-winding transformer formed by winding a conductor sheet and an insulating sheet one on top of the other is easy to manufacture in a large capacity and is easy to automate, and is expected to be a transformer for electric power in the future. As a feature of the sheet winding, it is necessary to use an insulator sheet having no pinhole in order to endure a voltage between turns with the insulator sheet. At present, it is difficult to manufacture an insulator sheet having no pinhole unless it is about 25 μm or more. Therefore, in consideration of the possibility that a pinhole exists, two insulating sheets having a thickness of 25 μm or more are used in an overlapping manner.

[0003] When winding the sheet winding, if the winding is not performed while applying tension, the winding is liable to be deformed such as slipping down into a bamboo shoot shape. Therefore, appropriate tension is applied to the conductor sheet and the insulating sheet. I am producing it. However, the conductor sheet is stretched and stretched due to the tension required to wind it, causing plastic deformation, and the width of the conductor sheet becomes shorter, and the width of the conductor sheet when it becomes a coil becomes shorter than the width in the material state. However, there were difficulties in matching design values with actual dimensions. Therefore, a hard metal sheet hardened in order to minimize this plastic deformation has been used as a conductor sheet for winding.

[0004] As a feature of the large-capacity sheet winding,
Since the windings are wound in close contact with each other, heat generated inside the windings due to resistance loss is difficult to escape, so that it is necessary to forcibly cool the windings. Therefore, a cooling panel or a cooling duct through which a cooling medium can flow must be provided in the middle of the winding.

[0005]

When a hardened hard metal sheet is used as a conductor sheet, there are the following problems. In other words, the panel that passes the cooling medium present in the sheet winding installed for cooling the windings, creates a path through which the cooling medium passes through a spacer between two metal plates. I have. Since the spacer and the two metal plates are fixed by welding, the entire panel is distorted at each portion. As a result, after the cooling panel and the conductor sheet are not well-fitted and the winding is completed, a gas gap is formed to cause a decrease in dielectric strength, and the gap increases the thermal resistance between the winding and the cooling panel. As a result, the number of cooling panels had to be increased, and not only the transformer was increased by the thickness thereof, but also the number of steps and the cost were increased. Especially,
When the thickness of the conductor sheet is increased, the mechanical strength in the thickness direction of the conductor sheet is increased, and a gas gap is easily formed, and the influence is remarkable.

Accordingly, an object of the present invention is to prevent a decrease in dielectric strength due to the formation of a gas gap in a sheet winding, and to reduce the thermal resistance due to the gas gap and reduce the number of cooling ducts or panels.

[0007]

SUMMARY OF THE INVENTION An annealing material is used for a metal sheet used for a conductor.

[0008]

[Function] By doing so, the conductor sheet is very soft, so the conductor sheet is tightened by the tension of the sheet applied during the production of the winding,
A gas gap is less likely to be formed due to close contact with the inner winding portion. Further, since the gas gap is reduced, the thermal resistance is reduced and cooling can be performed with a small number of ducts or panels.

As a result, since the number of cooling ducts or panels is reduced, the size of the winding is reduced, and the number of steps is also reduced, so that the manufacturing time is shortened and the cost is reduced. In addition, if the gap is shorter than the minimum value of the Paschen curve and a high electric field is not applied, dielectric breakdown of the gas gap will not occur, and the dielectric breakdown of the insulator sheet will not decrease and the reliability of the transformer will be greatly increased. it can.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, an O material (annealed) aluminum sheet is used for the conductor sheet 1 and 25 μm is used for the insulator sheet 2.
Two thick polyethylene terephthalate films are used.

When the conductor sheet 1 is formed in this manner, the case where the hardened aluminum sheet H material is used and the case where the soft O material is used are compared with the case where the hardened aluminum sheet is used. When the aluminum sheet is used, the aluminum sheet adheres well to the cooling panel 3, so that the heat transfer characteristic is improved by about 1.4 times as compared with the case where the H material is used. In addition, the gas gap does not become a defect, and a decrease in the dielectric strength of the insulating sheet 2 can be prevented. Reference numeral 4 denotes a spacer constituting the cooling panel 3.

The same effect can be obtained by using not only aluminum but also copper sheets for the windings of the conductor sheet 1 of the sheet winding transformer of the present invention. Further, the effect does not change even if an insulating sheet such as PEN, PEEK, or PPS is used as the insulating sheet 1 in addition to polyethylene terephthalate.

[0013]

As described above, according to the present invention, the gas gap in the sheet winding can be reduced, and a sheet winding in which the dielectric strength of the winding in which the gas gap becomes defective does not occur can be obtained. be able to. In addition, since the cooling characteristics are improved and the number of cooling ducts or panels can be reduced, the size of the windings can be reduced, the manufacturing time can be reduced, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the vicinity of a cooling panel of a sheet winding using an annealed sheet conductor of the present invention.

[Explanation of symbols]

 1: Conductor sheet 2: Insulator sheet 3: Cooling panel

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01F 27/28 H01F 41/12

Claims (1)

(57) [Claims] 1. A sheet-winding transformer formed by winding a conductor sheet and an insulator sheet, wherein an annealing material is used for a metal sheet constituting the conductor sheet.