JPS63216311A - Foil-wound transformer - Google Patents

Abstract

PURPOSE:To prevent a winding from being buckled and to enhance the cooling efficiency for the winding by a method wherein cooling panels into which a coolant is sealed and which are composed of an elastic insulator are inserted into an insulating space between an iron core and a low-voltage winding and into another insulating space between the low-voltage winding and a high-voltage winding. CONSTITUTION:After a low-voltage winding 4 and a high-voltage winding 5 have been put in a tank, cooling panels 21 composed of an elastic insulator such as rubber or the like are inserted into an insulating space between an iron core 2 and the low-voltage winding 4 and into another insulating space between the low-voltage winding and the high-voltage winding 5. A non- compressive coolant 23 such as Fluorinert FC 75 or the like is sealed into the cooling panels 21. Because the elastic cooling panels absorb the electromagnetic- mechanical force to be generated at the windings, it is possible to prevent the individual windings 4, 5 from being buckled.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a foil-wound transformer in which a cooling duct is built into a foil-like winding formed by overlapping and winding a metal sheet and an insulating sheet. It's about vessels.

(Prior art) A foil-wound transformer with suitable windings has a good winding space factor,
Because it has the characteristics of being compact and lightweight,
Small capacity transformers with relatively low voltages of about several 100 KVA have already been put into practical use and are widely used.

Recently, in view of the advantages of foil-wound transformers, higher voltage and larger capacity transformers, such as 275KV and 300M, are being developed.
Research is being conducted to expand its application to Anpachi transformers, but the most important technical point is how to improve the cooling capacity for the windings and provide the windings with high insulation capacity. Although it has not yet been put to practical use in such high-voltage, large-capacity transformers, the cooling method for the windings in foil-wound transformers is to incorporate cooling ducts within the windings to improve insulation properties. A so-called heat pipe type is being considered, which directly cools the heat generated from winding loss by feeding a high quality refrigerant.

FIG. 4 shows an example of a conventionally known foil-wound transformer of this type.

In the figure, a foil winding is provided inside a tank 1 filled with insulating oil or an insulating gas such as SFe gas as an insulating medium. This foil winding is the main pI of the iron core 2.
A low voltage winding 4 is wound around A2a via rfA@tube a, and a high voltage winding 5 is wound around the outside of this low voltage winding 4 via an insulating barrier 6. The low-voltage winding 4 and the high-voltage wire 5 are constructed by overlapping and winding a metal sheet 7 made of aluminum foil or the like and an insulating sheet 8 made of resin film or the like. Note that each of the windings 4 and 5 is insulated by an insulating medium sealed in a tank.

Furthermore, a cold duct 9 extending in the axial direction is wound around and built into the low voltage winding 4 and the high voltage wire 5. The inside of this cooling duct 9 contains Freon 113 and Fluorinert FC.
It is formed in a hollow shape so that refrigerant such as 75 can flow through it.
In the process of passing through the cooling duct 9 by this refrigerant, the winding 4,
5 is cooled.

The refrigerant that has absorbed the heat is sent out to the outside of the valley line and is transferred to tank 1.
The liquefied refrigerant is cooled and condensed by water cooling in a condenser 10 installed outside, and once stored in a refrigerant tank 1, it is pumped back into the cooling panel via a liquid guide pipe 13 and an insulated pipe 14 by a pump 12. sent. The conventional foil-wound transformer described above is generally called a separate foil-wound transformer because the cooling system in which the refrigerant circulates and the insulating gas of the winding are completely separated. This separate foil-wound transformer utilizes the latent heat of vaporization of the refrigerant, so
It can be expected to have excellent cooling characteristics and is promising as a Daigon D transformer. This type of transformer is USP-403999
Publication No. 0 is known.

However, the foil-wound transformer having such a configuration has the following problems. That is, when an external short circuit occurs in each winding 4.5, an excessive short circuit current flows, crushing the low voltage windings inward as shown by arrows 15a and 16b in FIGS. 5 and 6, and causing the high voltage windings to collapse. A radial electromagnetic mechanical force acts to push it outward. When this electromagnetic mechanical force moves, there is a risk that the metal sheet 7 will buckle in the low voltage winding 4 which has an insulating space between the iron core 2 and the winding.

Therefore, as shown in FIG. 5 and FIG.
In order to prevent the metal sheet 7 from buckling, a material 17 such as an insulating sheet is provided in the insulating space formed between the low voltage winding 4 and the low voltage winding 4 and the high voltage winding 5.

(Problems to be Solved by the Invention) Incidentally, in a foil-wound transformer having such a configuration, a pad 17 such as an insulating sheet 16 is provided in the insulating space. Reduced cooling efficiency between. Further, when assembling the windings 4 and 5, an insulation space must be secured by crossing each other due to insulation problems, and adjustment for setting the insulation distance is difficult and complicated.

The purpose of the present invention is to provide a highly reliable foil-wound transformer that eliminates the drawbacks of the prior art as described above, improves winding cooling efficiency without impairing short-circuit strength, and simplifies assembly. It's about doing.

[Structure of the Invention] (Means for Solving the Problems) The foil-wound transformer of the present invention has an elastic transformer in which a refrigerant is sealed in an insulating space formed between an iron core and a low-voltage winding and between a low-voltage winding and a high-voltage winding. A cooling panel made of WA rims is inserted.

(Function) In the foil-wound transformer of the present invention, a cooling panel made of an elastic insulator filled with a refrigerant is inserted into the insulating space formed between the core and the low-voltage winding and between the low-voltage winding and the high-voltage winding. This allows the cooling panel to come into close contact between the windings and the iron core, thereby preventing buckling of the windings.

(Example) Next, an example of the @-winding transformer of the present invention will be described with reference to FIG.

Note that the same parts as those in the prior art are given the same reference numerals and the description thereof will be omitted.

*Configuration of the embodiment* In FIGS. 1 to 3, after inserting the low voltage winding 4 and the high voltage winding 5 into the tank 1, the A cooling panel 21 made of an elastic insulating material such as rubber in an insulating space formed between the winding wire 5 and the winding wire 5.
is inserted.

A cooling pipe 22 is attached to the head of this cooling panel 21. A refrigerant 23 such as non-compressible Fluorinert FC75 is sent into the cooling panel 21 from the cold HD pipe 22 and sealed therein.

Effects of this embodiment* In the foil-wound transformer of this embodiment configured as described above, incompressible refrigerant 23 is present between the iron core 2 and the low voltage winding 4, and between the low voltage winding 4 and the high voltage winding 5. Cooling panel 2 with encapsulated elasticity
2, even if a short-circuit mechanical force occurs, the elastic cooling panel absorbs the electromagnetic mechanical force generated in the winding due to the electromagnetic mechanical force generated in the inner radial direction of the low voltage winding 4. In addition, since the windings 4 and 5 are in close contact with the iron core 2, buckling of the windings 4 and 5 can be prevented.

Effects of this embodiment* By providing the elastic cooling panel 22 in which the refrigerant 23 is sealed between the iron core 2 and each of the windings 4 and 5 in close contact with each other in this way, each winding 4 and 5 is exposed to external short circuits. Even if an accident occurs and excessive current flows, the metal sheet 7 of each winding 4, 5 will not buckle.

Furthermore, in the conventional foil-wound transformer, a pad 17 made of an insulating sheet or the like is provided between each winding 4, 5 and the iron core 2, but in this embodiment, a cooling material is used instead of the pad 17 such as an insulating sheet. By inserting the panel 21 and enclosing the refrigerant 23 such as Fluorinert FC75, the cooling efficiency between the core 2 and each winding 4.5 is greatly improved compared to a conventional foil-wound transformer.

In addition, the insulation space between the iron core 2 and each winding 4, 5 is
Due to insulation problems, it is necessary to secure a space due to the intersection, and in a conventional foil-wound transformer using a tab 17 made of an insulating sheet, it is necessary to set the insulating space while winding each sheet 7.8. Although it was difficult to adjust the insulation space, as shown in Figures 2 and 3, each winding 4 and 5
After inserting the cooling panel 4 made of rubber or the like, cold 123 such as Fluorinert FC75 is applied to inflate the panel, and the insulating space between the low voltage winding 4 and the iron core 2 is tightly attached by the swollen cooling panel 21. You can easily set the insulation space by simply setting the Furthermore, since the insulation space can be easily set, assembly of the windings 4 and 5 can be simplified.

[Effects of the Invention] As described above, according to the present invention, there is provided a cooling panel made of an elastic insulator in which a refrigerant is sealed in an insulating space formed between an iron core and a low-voltage winding, and between a low-voltage winding and a high-voltage winding. The simple structure of inserting the metal sheet prevents buckling of the metal sheet due to short-circuit mechanical force, improves the cooling efficiency between the windings, and provides a highly reliable foil-wound transformer with simplified assembly. became.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the winding structure of a foil-wound transformer of the present invention, Figs. 2 and 3 are longitudinal sectional views of Fig. 1, and Fig. 4 is a foil-wound transformer with a conventional structure. FIG. 5 is a cross-sectional view showing a conventional winding structure, and FIG. 6 is a vertical cross-sectional view of FIG. 5. DESCRIPTION OF SYMBOLS 1... Tank, 2... Iron core, 3, 16... Insulating tube, 4... Low voltage winding, 5... High voltage winding, 6... Insulating barrier, 7... Metal sheet , 8... insulation sheet, 9
...Cooling pulse, 10...Condenser, 11...Refrigerant tank, 12...Pump, 13...Liquid guide pipe, 14...
...Insulating pipe, 15a, 15b...Direction of electromagnetic mechanical force, 17...Filling, 21...Cooling panel, 22.
...Cooling piping, 23... Refrigerant.

Claims (1)

[Claims] A metal sheet and an insulating sheet are layered and wound around the outer circumference of the iron core to form a foil winding, and a cooling panel with a refrigerant circulating inside is built into this winding to form the inside of the transformer. In a foil-wound transformer where the contents of the transformer are housed in a tank filled with an insulating medium, a cooling panel filled with a refrigerant is inserted into the insulating space formed between the core and the low-voltage winding and between the low-voltage winding and the high-voltage winding. A foil-wound transformer characterized by: