JP2597683B2 - Foil-wound transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention includes a sheet-shaped winding, improves the dielectric strength of the sheet-shaped winding, and simplifies the work for winding assembly. The present invention relates to a foil-wound transformer.

(Prior art) Foil-wound transformers with sheet-shaped windings have a good space factor of the windings and have the characteristics of realizing small size and light weight.
It has already been put into practical use and widely used in small capacity transformers with a relatively low voltage of about 100 KVA.

In recent years, in view of the advantages of such foil-wound transformers, research has been conducted on expanding the application to higher-voltage, higher-capacity transformers, such as 275KV and 300MVA class transformers. It is a matter of improving the cooling capacity of the wire and giving the winding a high insulation capacity. As a method of cooling the winding in such a foil-wound transformer, a cooling duct is built in the winding, and a refrigerant having excellent insulation properties is fed to directly cool the heat generated from the winding loss. A heat pipe type is being considered.

FIG. 6 shows an example of the structure of such a foil-wound transformer. In the figure, an insulating gas such as SF ₆ gas is sealed at a high pressure as an insulating medium in a tank 1, and an iron core 2 is provided inside the tank 1. Outside the main leg 2a of the iron core 2, a low-voltage winding 4 is provided via an insulating gap 6a and an insulating cylinder 3.
The high voltage winding 5 is wound around the low voltage winding 4 via an insulating barrier 6b. These low voltage windings 4
The high-voltage winding 5 is constituted by a sheet-like winding formed by superposing and winding a metal sheet 7 made of aluminum foil or the like and an insulating sheet 8 made of polyester film or the like.
The windings 4 and 5 are insulated by an insulating medium sealed in the tank 1. A cooling duct 9 extending in the axial direction is wound around and built in the low-voltage and high-voltage windings 4,5. The inside of the cooling duct 9 is hollow so that a refrigerant such as Freon 113 or Fluorinert FC75 passes therethrough, and this refrigerant cools the windings 4 and 5 while passing through the inside of the cooling duct 9. This refrigerant is cooled by a cooler 11 provided outside the tank 1 and circulated by a pump 10.

The conventional foil-wound transformer described above is generally referred to as a separate-type foil-wound transformer because the cooling system in which the refrigerant circulates and the insulating medium 12 for insulation are completely separated from each other.
Compared with conventional transformers using rectangular conductors and insulating oil, they can be made much smaller and lighter and are promising as large capacity transformers. US Pat. No. 4,039,990 is known as this type of transformer.

(Problems to be Solved by the Invention) Since the winding structure of such a conventional foil-wound transformer is an integrated winding structure in which the low-voltage winding 4 and the high-voltage winding 5 are wound in order, If the low-voltage winding 4 on the side has a problem, it must be disassembled from the high-voltage winding 5 on the outer peripheral side, which is very troublesome in winding assembly. In addition, since the winding diameter becomes large due to the integral winding structure, the layers may shift due to their own weight during the assembling work.

Further, the insulating barrier 6b serving as a main gap between the low-voltage winding 4 and the high-voltage winding 5 is padded with an insulating material such as a laminate of polyester fill sheets. A small gas gap of the insulating medium is formed between the insulator and the insulating cylinder 3. Electrolysis is concentrated in the gas gap due to a difference between the minute gas gap and the dielectric constant of the insulator. There was a problem that dielectric breakdown occurred.

The present invention has been made in order to improve the above-mentioned disadvantages, and ensures insulation of an insulating barrier portion, simplifies the work at the time of winding assembly, and has sufficiently high reliability for a transport / short-circuiting machine. An object is to provide a foil-wound transformer.

[Configuration of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a method of separately winding a low-voltage winding and a high-voltage winding, providing an insulating gas gap between the low-voltage and high-voltage windings, and A supporting structure is inserted into an insulating gas gap, and the supporting structure is fixed and supported by a groove or a support of an insulating cylinder.

(Operation) Since the low-voltage and high-voltage windings are separately wound in the above-described structure, the work of assembling the windings is simplified, and the layer shift due to the own weight can be prevented.

Further, since the insulating gap portion serves as a gas space of the insulating medium, electrolysis does not concentrate and the insulating distance can be reduced, so that the winding can be made compact.

Further, by inserting a support structure into the insulating gap portion, the insulator is made reliable, and buckling of the metal sheet due to short-circuit mechanical force is prevented.

(Embodiment) An embodiment of the present invention will be described below with reference to FIG. 1 and FIG.

The low-voltage winding 4 and the high-voltage winding 5 are individually wound around the insulating cylinder 3. Therefore, when assembling the windings, the low-voltage winding 4 having the smaller diameter and then the high-voltage winding 5 having the larger diameter are separately inserted into the iron core main leg 2a to form the winding.

The insulating barrier 6 between the low-voltage winding 4 and the high-voltage winding 5 is a gas space for an insulating medium 12 such as SF ₆ gas.

On the insulating barrier 6 between the low-voltage winding 4 and the high-voltage winding 5, support structures 16 made of a rectangular insulator are arranged side by side in a circumferential direction at a length shorter than the height of the metal sheet 7. Thus, it is fixed circumferentially and upward and downward by a groove 3a provided at the upper end of the insulating cylinder 3.

According to this structure, by separately winding the low-voltage and high-voltage windings 4 and 5, the winding rewinding operation caused by the failure of the low-voltage winding 4 and the like can be performed by the low-voltage winding 4 alone, and the winding operation is simple. Not only that, but the diameter of the single winding is smaller than that of the one-piece winding structure, so that the metal sheet itself can be prevented from being displaced.

Further, a support structure 16 inserted between the low-voltage and high-voltage windings 4 and 5
Is longer but shorter than the edge of the end of the metal sheet 7 where the dielectric breakdown is likely to occur, so that a gas gap is provided at the end, which has the effect of alleviating electrolysis. However, there is an advantage that the cooling efficiency of the winding increases because there is no padding at the end.

When a short circuit is applied to the windings, a short-circuit mechanical force is applied to the low voltage winding 4 on the inner diameter side and the high voltage winding 5 to the outer diameter side both in the radial direction. Here, the low-voltage winding 4 attempts to deform to the inner diameter side due to mechanical force, but since the inner diameter side is restrained by the insulating cylinder 3,
The winding tends to deform to the outer diameter side where the support structure 16 is disposed. At this time, if the support structure 16 is displaced in the circumferential direction and is disturbed in arrangement, there is a problem that the winding is deformed in a wide space between the support structures and buckling occurs. However, in the present invention, since the support structure 16 is fixed by the groove 3a provided in the insulating cylinder 3, it does not shift in the vertical and circumferential directions, and therefore, prevents buckling of the winding due to short-circuit mechanical force. It becomes possible.

The same effect can be obtained even if the support structure 16 is fixed to the insulating tube 3 by bonding.

 3 to 5 show another embodiment of the present invention.

Assembling work of the winding is similar to the embodiment shown in FIG.
The high voltage windings 4 and 5 are separately wound and assembled.

At this time, the support structure 16 is fixed to the band-like support structure support 17 of about two divisions by bonding or mechanical bonding in a circumferential direction at a length where spaces are provided at both ends of the metal sheet. The ends of the support structure support 17 are fastened and fixed to a metal sheet by bonding or the like.

According to this structure, as in the embodiment shown in FIG.
Is fixed to the metal sheet by the support structure support 17, so that buckling of the winding due to short-circuit mechanical force can be prevented without shifting vertically and circumferentially.

〔The invention's effect〕

As described above, according to the present invention, the operation at the time of winding assembly is simplified, the insulation of the insulating barrier is ensured,
In addition, it is possible to obtain a foil-wound transformer that is sufficiently reliable with respect to transport and short circuit mechanical force.

[Brief description of the drawings]

FIG. 1 is a plan view of a winding structure of a foil-wound transformer showing one embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, and FIG. FIG. 4 is a plan view showing another embodiment, FIG. 4 is a sectional view taken along the line BB in FIG.
The figure is a detailed view of the support structure and the support, and FIG. 6 is a sectional view showing a schematic configuration of a conventionally used foil-wound transformer. DESCRIPTION OF SYMBOLS 1 ... Tank, 2 ... Iron core 3 ... Insulating cylinder, 4 ... Low voltage winding 5 ... High voltage winding, 6 ... Insulation barrier 7 ... Metal sheet, 8 ... Insulating sheet 9 ... Cooling duct, 10 Condenser 11 Refrigerant tank 12 Pump 13 Liquid guide tube 14 Insulating pipe 15 Insulating tape 16 Support structure 17 Support structure support

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Tanaka 2-4 Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Keihin Plant, Toshiba Corporation (72) Inventor Hideo Hirose 2-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa-ken No. Inside the Toshiba Hamakawa Plant

Claims (3)

(57) [Claims] 1. A low-voltage coil and a high-voltage coil in a foil-winding transformer having a cooling panel for circulating a refrigerant inside a foil-shaped winding in which a metal sheet and an insulating sheet are superposed and wound on an iron core. A supporting structure shorter than the metal sheet height is arranged in the circumferential direction so that a space is provided at both ends of the metal sheet in the insulating gap between the supporting members, and the supporting structure is inserted and fixed in an insulating cylinder having a groove. A foil-wound transformer characterized by the following: 2. A patent wherein a support structure shorter than the height of the metal sheet is circumferentially arranged so that spaces are provided at both ends of the metal sheet, and the support structure and the insulating cylinder are fixed by bonding. The foil-wound transformer according to claim 1. 3. A support structure shorter than the height of the metal sheet is arranged in the insulating gap between the low-voltage coil and the high-voltage coil in a circumferential direction so that spaces are provided at both ends of the metal sheet on a belt-like support. 2. A foil-wound transformer according to claim 1, wherein said foil support is fixed by bonding or mechanical bonding with insulating bolts or the like, and said support and support are fastened and fixed to said support and support metal sheet by bonding or the like.