JPS58220417A - Manufacture of foil coil - Google Patents

Abstract

PURPOSE:To avoid damage to an insulation sheet due to turning back of cut edges and raise reliability of transformer or others by stacking a plurality of metal sheets while the cut edges that turn back in cutting are laid opposite to those of next sheet and stacking insulation sheets between windings of the sheet when metal sheets and insulation sheets are stacked to form a foil coil. CONSTITUTION:A metal sheet 2 that is wound in a roll is supported on a reverse rotating roll 21 and a similar sheet 2' that is to be laid on the sheet 2 is supported on a positive rotation roll 22. Both sheets 2 and 2' are transferred to a compression device 24 via guide roller 23 with the sections that turn back of both sheets on the same side of the sheet. After they are compressed, they are made foil coils by a winding machine 27. At the same time roll-shape insulation sheets 3 from a plurality of rotating rolls 25 are placed between windings of the sheets 2 and 2' along the face where there is no cut edge that turns back to form a foil coil 5. With this arrangement the electric field at both sides is made smaller by several tenths and thereby a transformer with a super-high voltage foil coil can be provided.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a foil-like winding in which a metal sheet and an insulating sheet are layered and used in stationary induction equipment in which a needle leg duct is built into the winding. The present invention relates to a method of manufacturing a foil-wound wire.

[Technical background of the invention and its problems]

Foil-wound transformers have a good space factor, so they have the advantage of being smaller and lighter. It has already been put into practical use in relatively low voltage, small capacity transformers of several KV and several hundred KV A.

Recently, in view of its merits, research has been conducted to expand its application to higher voltage and larger capacity transformers, such as 275 KV and 300 MVA. The biggest key lies in how we can improve the cooling capacity and provide high insulation capacity to the windings. Although such high-voltage, large-capacity transformers have not yet been put to practical use, foil-wound transformers, which are already known and are being researched, have cooling ducts built into the windings and have excellent insulation properties. A so-called heat pipe type transformer is considered, in which a refrigerant is pumped in and the heat generated from winding loss is directly cooled. Figure 1 shows the structure of a conventional foil-wound transformer. A metal sheet 2 and an insulating sheet 3 are stacked on the outside of the iron core 1, and a low voltage winding 4 and a high voltage winding 5 of a known foil winding method are wound, and an annular cooling duct 6 is built in between these windings. This cooling duct 6
There is a thin gap inside, filled with refrigerant 15 such as Freon R-113 or Fluorinert FC75, and the pump 7
There is a known method in which the vapor is passed through a foil spring winding, and the heat generated in the foil spring winding is taken away by the latent heat of vaporization of the refrigerant, and the vapor is cooled and condensed by a water cooling device 9 in a condenser 8. A refrigerant circulation cooling circuit is used in which liquefied refrigerant is stored in a refrigerant tank 14 and further fed into the windings by a pump 7. That is, the refrigerant circulation circuit and the transformer are separated.

The liquid collection f10 is made of metal such as stainless steel,
In order to connect it with the cooling duct 6, insulated pipe 1
1 is used, and the liquid collecting pipe 10 takes the ground potential of the tank 12, etc. The potential of the cooling duct 6 is electrically coupled to the same potential as the winding 4.5 since it is wound within the winding 4.5.

The windings 4 and 5 are insulated by an insulating medium 13 such as insulating oil, 8F, or gas sealed in a tank 12.

Note that, in FIG. 1, the lead wires of the windings 4.5 and the bushings for leading them out to the outside of the tank 12 are omitted.

In a transformer of this type, the circulation circuit in which the refrigerant flows for cooling and the insulating medium 13 for insulation are completely separated by the molecule m (
separated). For this reason, this type of foil-wound transformer is particularly referred to here as a separate foil-wound transformer.

This separate foil-wound transformer utilizes the latent heat of vaporization of the refrigerant, so it can be expected to have excellent cooling characteristics, making it promising for large-capacity transformers. However, the foil-wound metal sheet 2 of the conventional separate foil-wound transformer as shown in FIG. 1 has the following problems.

Generally, the metal sheet 2 of the foil-wound windings 4 and 5 is an aluminum sheet or a copper sheet with a thickness of several microns to several hundred microns. Both ends of this metal sheet 2 are cut to a predetermined width using various cutting methods, but if the width exceeds a certain level, it is difficult to process the ends. As shown, there is a burr 2m. An example of the cross-sectional shape of a conventional foil-wound winding 4.5 using such a metal sheet 2 is shown in FIG. Since the end burr 2a of the metal sheet 2 is in direct contact with the insulating sheet 3, the burr 2a of the metal sheet 2 becomes a protrusion that cuts the insulating sheet 3 or makes a hole. As the insulation performance of the insulating sheet 3 disappears and the electric field intensity between the five layers of foil winding increases as the transformer becomes an ultra-high voltage transformer, the electric field concentration on the burr 2m of the metal sheet 2 is reduced to the center of the metal sheet 2. It becomes several times larger than the other parts, and induces dielectric breakdown between the five layers of the foil-wound winding or creeping dielectric breakdown.

That is, it is no exaggeration to say that the insulation design potential gradient of the low-voltage winding 4 and the high-voltage winding 5, which are foil-wound windings, is limited by the burr 2m of the metal sheet 2;
How to improve a is a technical problem in foil-wound wire insulation.

[Purpose of the invention]

The present invention provides a wire manufacturing method that eliminates the above-mentioned conventional drawbacks, prevents damage to the insulating sheet due to the burrs of the metal sheet, and improves the insulation performance.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention comprises laminating a complete set of sheets and an insulating sheet, by electrically energizing a plurality of metal sheets so that the surfaces having burrs generated when they are cut face each other, and applying a predetermined pressure. The insulating sheet is laminated on the surface of the metal sheet opposite to the surface having the burr.

[Embodiments of the invention]

Hereinafter, the present invention will be explained with reference to the drawings. Figure 14 is a schematic diagram of the manufacturing process of the foil-wound wire according to the present invention, (a) is a cross-sectional schematic diagram before the metal sheet 2 passes through the compression device, and (b) is a plan view showing the process flow of the manufacturing method. , (C) is the compression device U
FIG. 2 is a schematic cross-sectional view of the metal sheet 2 after passing through. Similarly, FIG. 5 is a schematic diagram showing the method for manufacturing the foil-wound wire of the present invention, and FIG. 6 is a modification of FIG. 4.

The same parts in FIGS. A4 to 6 are designated by the same reference numerals and will be described below. 11145A reversing table 21 that supports and rotates the metal sheet 2 wound into a roll as shown in the figure.
, a normal rotation table n that supports and rotates the metal sheet 2' similarly wound into a roll, a guide roller n that guides the metal sheets 2, 2', a compression device, and an insulating sheet wound into a roll. Rotating table δ that supports and rotates 3 and insulating sheet 3
A winding machine n, etc., is used for laminating and winding the insulating sheets 3, rollers, and metal sheaths 2, 2' to form the foil-wound windings 5.

The metal sheet 2, which is wound by the winding machine 27 from the reversing table 21 rotated by the tensile force of the winding machine n, and the metal sheet 2', which is similarly wound from the normal rotating table n to the winding machine 27, pass through guide rollers. It is compressed by different compression devices and in the previous process, as shown in Fig. 4(a).
The burrs 2a of the metal sheet 2 and the separate metal sheet 2' are arranged to face each other as shown in FIG. Their arrangement is such that the metal sheets 2' pulled from the forward rotation table η are arranged in two rows in parallel at the bottom, with their burrs 2a facing upward, and the metal sheets 2' pulled from the forward rotation table η
The metal sheets 2 pulled from 1 are arranged in one row with their □, :, burrs 2a facing downward 11*, and on both sides of this, two rows of short metal sheets 2' are arranged in a total of 3 rows on the top. The structure is as follows.

Each metal sheet 2.2' thus arranged.

2# flows in the direction of the winding machine n as shown by the arrow x in Fig. 4(b), and is compression-molded by a compression device placed in front of the winding machine n, as shown in Fig. 4(e). Upper metal sheet 2
The short sheet 2# and the lower metal sheet 2' face each other in close contact with each other, and each metal sheet arc end portion 2b has a preferable arc shape different from the previous process burr portion 2a. The metal sheets 2.2', 2', which are compression-molded and configured with the burrs 2 facing each other in close contact, are insulated as shown in FIG. sheet 3
Together with this, the coils are laminated and wound by a winding machine n to form a foil-wound coil 5'.

FIG. 6 shows a modification of the present invention, in which the burrs 2a at one end of the upper metal sheet 2 and one end of the lower metal sheet 2' are compressed in the direction of the arrow Y to bring them into close contact with each other, and each metal sheet is attached to the other end. )2.2' This is a foil-wound winding 5 similar to the above, which is formed by arranging an insulator 4 having the same thickness as 2.2'.

As described above, the foil-wound winding 5 manufactured by improving the metal sheet burr 2a reduces the electric field at both ends of the winding, prevents electric field concentration, and has a higher potential gradient than the conventional foil-wound winding. Not only is the strength reduced to a fraction of that, the glabella ultimate strength is improved, and the edge creepage failure characteristics are improved, but also the burr portion 2a
- The insulating sheet 3, which is laminated and wound together, will not be damaged or holes will be made, thereby impairing the insulating performance, and higher reliability can be obtained. It is clear that these effects increase as the voltage and capacity of the differential transformer increases.

〔Effect of the invention〕

As explained above, the foil-wound winding manufactured according to the present invention reduces the IK of the winding end electric field by several minutes, improves insulation reliability, enables a more compact insulation design, and improves the reliability of the winding and transformer. It is possible to provide an ultra-high-voltage, large-capacity, foil-wound transformer that is smaller and lighter, has improved insulation performance, and has a longer lifespan.Therefore, it is possible to provide an ultra-high-voltage, large-capacity, foil-wound transformer that saves energy, is smaller and lighter, and has improved insulation reliability. .

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the structure of a conventional foil-wound transformer;
The figure is an enlarged view of a cut surface of a metal sheet, FIG. 3 is a cross-sectional view of a conventional foil-wound wire, FIG. 14 and FIG. This is a modification according to the present invention. l...Iron core 2...Metal sheet 3...
・Insulating sheet 4...Low voltage winding 5...High voltage winding 6...Cooling duct 7...Pump
8... Condenser 9... Water cooling 10... Liquid collection pipe 11... Insulated pipe 12... Tank 13
... Insulating medium 14 ... Refrigerant tank 15 ...
・Refrigerant 21... Reverse rotation table n... Forward rotation table
Ru... Guide roller U... Compression device, 25
...Rotating table...Guide roller a...Winding machine path...Insulator 2a...Metal sheet burr part 2b...
Arc end of metal sheet (7317) Agent: Patent attorney Kensuke Norichika (and one other person) Fig. 1 8 1υ Fig. 2 Fig. 3 Fig. 4- Fig. 5

Claims (1)

[Claims] In a method for manufacturing a foil-wound wire constructed by laminating a metal sheet and an insulating sheet, a plurality of metal sheets are stacked so that the surfaces having burrs generated when the sheets are cut are facing each other, and the metal sheets are brought into close contact with each other under a predetermined pressure. A method for manufacturing a foil-wound wire, characterized in that an insulating sheet is laminated on a surface opposite to a surface having a burr.