JPS6065503A - Foil-wound transformer - Google Patents

Abstract

PURPOSE:To obtain the foil-wound transformer which is easily manufactured and has a high economical efficiency and which has a long operation life by eliminating the possibility of a looseness or a fall of a winding and a leakage of a cooling medium by winding a thin tube spirally at winding a coil to compose a cooling duct. CONSTITUTION:A cooling duct 9 is composed by winding a thin tube spirally at winding a coil. The long thin tube is used and it is wound at winding of the coil together with a metallic sheet 7 and an insulating sheet 8 with a tension to form the cooling duct 9. Accordingly, fabrication of the cooling duct 9 is facile and an economical efficiency is high. Also, as it has good flexibility, the contact of the duct 9 and each part of the winding on a periphery of the duct is tight and a sufficient fastening force can be retained. Accordingly, there is no possibility that the winding loosens or falls. Also, as the cooling duct is uniform in a diameter over the whole length, a cooling medium can circulate smoothly thereby enabling the efficient cooling of the winding. Besides, as the whole cooling duct is formed by one thin tube, welding is not necessary at all and the problem of a leakage of a cooling medium caused by cracks or corrosion of the welded parts can be solved.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a method for winding a foil winding formed by winding a metal sheet and an insulating sheet 1 through the middle around the leg of a wire arm; This relates to a foil-wound transformer that has a built-in cooling duct that serves as a refrigerant flow path within the line, and particularly relates to a foil-wound transformer that has an improved cooling duct (J11 configuration).

[Technical field of the invention] A foil-wound transformer equipped with a foil winding has a good winding space factor,
Due to its characteristics of being compact and lightweight,
It has already been put to practical use in small volume transformers with relatively low voltages of about several hundred kilovolts.

Recently, in view of its excellent advantages, high voltage and human capacity fl)
Research is underway to expand its application to transformers, such as 275KV and 300MVA class transformers, but the challenge for practical application is how to improve the cooling capacity for the windings and how to provide the windings with a high 18-edge capacity. The point is whether or not they can be kicked. As a second method for cooling the windings of such foil-wound transformers, a cooling duct 1 is built into the windings, and a refrigerant with excellent insulating properties is fed into the windings to absorb heat generated from winding losses. A type of heat pipe that directly cools the device is being considered.

That is, as shown in FIG. 1, a tank 1 is filled with insulating oil or an insulating gas such as SF6 gas as an insulating medium, and an iron core 2 is provided inside the tank 1. This iron core 2
A low voltage winding 4 is wound around the outside of the leg portion 2a via an insulating cylinder 3, and a high voltage winding 5 is wound around the outside of this low voltage winding 4 through an insulating barrier 6. These low voltage winding 4 and high voltage winding 5 are connected to a metal sheet 7 made of aluminum foil or the like.
and an insulating sheet 8 made of a resin film or the like are layered and wound to form a foil winding.

Further, a cold In duct 9 extending in the axial direction is wound around the low-voltage and high-voltage windings 4 and 5 and is built therein. Inside the cooling duct 9, Freon R-113 and Fluorinert FC7 are used.
It is hollow so that a refrigerant such as No. 5 can flow therethrough, and in the process of passing through the cooling duct 9, this refrigerant absorbs heat from the winding 4.5 using the latent heat of evaporation of the refrigerant, thereby cooling the winding 4.5. This refrigerant is cooled by exchanging heat with cooling water in a condenser 10 provided outside the tank. l'I and condensed. The liquefied refrigerant is stored in a refrigerant tank 11 and then sent into the cooling duct 9 by a pump 12 via a liquid conduit 13 and an insulated pipe 14. In addition, metal liquid guiding pipe 1
3 is arranged on both end sides of the windings 4 and 5, and cooling ducts 1 to 9
Refrigerant inlet/outlet ports 15a, 15b are formed in the drawing: part, and the refrigerant inlet/outlet ports 15a, 15 of the cooling duct 9, such as the liquid guide pipe 13, are formed.
It is connected to tl via an insulating pipe 14.

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 properties and is promising as a large-capacity transformer.

[Problems with the background technology] However, on page 1)! A conventional transformer such as the IS type has a cooling duct 1-0 built into the windings 1 and 5, and a second cooling duct 1-0.
Since a cylindrical duct as shown in the figure (Δ) or a divided cylindrical duct 1 as shown in FIG. 2(B) is used, the following problems arise.

That is, the cylindrical cooling duct 9 shown in FIGS. 2(A) and 2(B)
In this case, it is essential that the refrigerant that flows in from the refrigerant inlet 15a flows uniformly throughout the duct, and that the refrigerant that has passed through the duct flows out from the refrigerant outlet 15b without stagnation in the upper part of the duct. In each of the cooling ducts 9, a pipe-shaped refrigerant passage 16.16 is formed along the circumferential direction in the lower part of the cooling duct 9.

However, in manufacturing this cooling duct 9, J, ZuA
A cylindrical body is manufactured by bending a 9-inch metal plate into a cylindrical shape and welding the abutting V edges of the cylindrical body. Next, this cylindrical body is flattened from both sides, excluding the portions that will become the liquid guide channels 16 and 16. This required a very time-consuming process of crushing the duct to form a duct with a minute gap, and then closing the open ends on both sides by welding, which resulted in a problem of low workability.

J: The winding is wound around the metal sheet 7 and the insulating sheath 1-8 under tension, and the tightening is caused by the force J:
It is fixed to the leg portion 2a of the iron core and the insulating barrier 6. Therefore, when inserting the cooling duct 9, it is necessary to match the winding dimension of the winding with the inside diameter of the cooling duct to ensure sufficient tightening.

However, since it is difficult to match the inner diameter of the conventional cylindrical cooling lug with the winding dimensions using the manufacturing method described above, the winding must be sufficiently tightened in the cooling duct. No force is obtained, and a small gap is created between the winding and the cooling duct. In such a winding, the tightening force decreases due to the winding fitting into the cooling duct, and there is a risk that the winding may shift or fall during operation, which has also been a problem.

Furthermore, although the cooling ducts 1 to 9 are manufactured under strict quality control to ensure that there are no leakage points, since they have many welded points, the welded parts may wear out over a long period of use. There is a risk that the refrigerant may deteriorate due to corrosion, etc., or become tacked, causing the refrigerant to leak. Although this refrigerant leakage occurs in very small amounts, the amount of refrigerant in the refrigerant circulation system gradually becomes insufficient, which reduces the cooling capacity and causes the transformer to overheat. Therefore, the conventional transformer using the cooling duct 9 has a short operating life, and it is impossible to use it for power transformers, etc., which require a life-saving operation after about 30 years. .

[Object of the Invention] The present invention has been devised in order to eliminate the drawbacks of the conventional foil-wound transformer as described above, and its purpose is particularly to improve the cooling duct thereof. It is an object of the present invention to provide a capacitive pressure vessel 9 which is easy to use, has an excellent warp 111, eliminates the fear of winding displacement and falling, and has a good operating life.

[Summary of the Invention] The foil-wound transformer of the present invention has a structure in which a cold section duct is constructed by winding a thin tube in a spiral shape when winding a winding.
The duct has sufficient winding tightening force and eliminates the cooling duct weld.

[Embodiment of the Invention] An embodiment of the present invention will be specifically described below with reference to the drawings.

FIG. 4 shows the process of winding the metal sheet 7, the insulating sheet 8, and the cooling duct 9 into the cooling duct 1, and FIG. 5 shows the low-voltage winding 4 incorporating the cooling duct 1-0. Furthermore, M/
In FIG. I and FIG. 5, the metal sheet 7 and the insulating sheet 8 constituting the foil winding are shown as one sheet.

As shown in FIG. 5, the cooling duct 9 is constructed of a long thin tube made of metal or heat-resistant synthetic resin when the low-voltage winding 4 is wound.
It is constructed by being rolled together with a metal sheet 7 and an insulating sheet 8. Further, as shown in FIG. 5, one end of the cooling duct 9 extends downward to form a refrigerant outlet 15a, and the (l!!) end extends upward to form a refrigerant outlet 15b, and
Although not shown, the refrigerant population 15a and the refrigerant outlet 15b
is connected to the liquid conduit for guiding the refrigerant in the same way as the conventional transformer shown in FIG.

In addition, in the foil-wound transformer of the present invention, except for the cooling duct 9, the first
It has the same configuration as the conventional transformer shown in the figure. Therefore, if the cooling duct 9 is made of metal, the refrigerant population 1
5a and the refrigerant outlet 15b, and the liquid conduit pipe etc. are connected via an insulated pipe 1) as in the conventional case. On the other hand, when the cooling duct 9 is made of synthetic resin, the refrigerant inlet 15a and refrigerant outlet 15b can be directly connected to the liquid guide pipe.

The function of the foil-wrapped transformer of the present invention having the above configuration is as follows.

That is, since the cooling duct 9 is formed by applying tension to the metal sheet 7 and the insulating sheet 8 when winding one winding using a long thin tube, the cooling duct 9 is extremely easy to manufacture. Therefore, it is also highly economical. In addition, since the cooling ducts 1~, which are spirally wound thin tubes, are more flexible than conventional cooling ducts, they have good adhesion to each part of the windings on the inner and outer peripheries of the cooling duct 9, and sufficient tightening requires less force. Therefore, there is no fear that the windings will shift or fall. The thin tubes constituting the cold duct 9 are cylindrical and strong in the radial direction, so the tension of the windings causes
il is never performed. Further, since the cooling duct has the same diameter over its entire length, the coolant can be circulated smoothly, and the windings can be efficiently cooled. In addition, there is no need to form the entire cooling duct with a single thin tube, or to weld it, thereby eliminating the problem of refrigerant IIII+1 due to corrosion and cracking of welded parts.

In this embodiment, only a low-voltage winding is shown, but the present invention can be similarly applied to a high-voltage winding. In addition, cooling duct 1
~ is not necessarily limited to one #I tube, but may be composed of a plurality of thin tubes.

[Effect of the Invention 7] As described above, according to the present invention, by winding the thin tube in a spiral shape when winding the winding to form the cooling duct,
It is easy to manufacture cooling ducts and is highly economical, and since the windings are tightened sufficiently, there is no risk of the windings slipping or falling, and since there are no welds, there is no problem of refrigerant leakage. It is possible to provide a foil-wound transformer that has a long life and is free from problems.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional foil-wound transformer, and Figure 2 (△
)(B) is a perspective view showing a cooling duct used in a conventional foil-wound transformer, FIG. 3 is a sectional view showing the end of the cooling duct in FIG. 2, and FIGS. 4 and 5 are 1 is a dimensional drawing of an embodiment of the foil-wound transformer of the present invention, a perspective view showing a means for winding a cooling duct into the winding, and a front view showing a foil winding incorporating a cooling duct. be. 1...tank, 2...iron core, 2a...leg, 3...
...Insulating tube, 4...Low voltage winding, 5...High voltage winding, 6
...Insulating barrier, 7...Metal sheet, 8...Insulating sheet, 9...Cold In duct, 1o...Condenser, 1
DESCRIPTION OF SYMBOLS 1... Refrigerant tank, 12... Pump, 13... Liquid guide pipe, 14... Insulated pipe, 15a... Refrigerant inlet,
15b... Refrigerant outlet, 1G... Liquid guiding path. 7317 Representative Patent Attorney Kensuke Norichika (1 person) Figure 1 Figure 2 (A) (B) 9J3 Figure 4 Figure 5

Claims (1)

[Claims] The El-leg of the button and center is wrapped with a foil winding made by overlapping metal sheets and insulating sheets, and a cold 1111 duct that serves as a coolant flow path is provided within the winding. In the built-in foil-wound transformer, )'+'77Jlguku1- is constructed by winding one or more thin tubes in a spiral shape when winding the winding.