JPH05315150A - Foil-wound transformer - Google Patents

Abstract

PURPOSE:To provide a foil-wound transformer that is easy for maintenance along with advantages in cooling performance, easy treatment of a refrigerant, and cost-effectiveness of a cooling system. CONSTITUTION:A conductive sheet and an insulating sheet are piled and wound to form a foil-wound winding 3. The foil-wound winding 3 and an insulating medium 22, such as a gel insulating material, are sealed in a tank 21. A cooling means 4 like a cooling panel is provided inside or outside the foil-wound winding 3 in the tank 21, and a refrigerant 25 is circulated from refrigerant circulating means 23 and 24 through a cooling pipe 9 to the cooling means 4. Purified water is used as the refrigerant 25, and a demineralizing means 26, such as an ion exchange resin, is provided to keep the refrigerant 25, which flows into the cooling means 4, in a purified state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foil winding transformer having a foil winding winding in which a metal sheet and an insulating sheet are stacked and wound, and a cooling panel is provided in the winding.

[0002]

2. Description of the Related Art Foil-wound transformers have a high winding space factor and are excellent in that they can be made smaller and lighter. Therefore, transformers of several hundred kVA in the low voltage class have already been put into practical use. There is. In recent years, such foil wound transformers have been
Further, a high voltage large capacity device (for example, 275 kV-300
Technology for expanding application to MVA class) is being researched and developed, but the biggest technical problem in this case is improvement of cooling performance and securing of high insulation performance of windings.

Conventionally, as such a large capacity transformer,
A foil wound transformer as shown in FIG. 5 has been considered. That is, in the tank 1, the transformer contents including the iron core 2, the foil winding 3 formed around the iron core 2, and the cooling panel 4 built in the foil winding 3 ensure the ground insulation performance. It is enclosed together with SF ₆ gas 5, which is an insulating medium. Then, shields 6 for alleviating an electric field are provided on the upper and lower ends of the outer peripheral surface of the foil winding 3.

Further, outside the tank 1, a cooler 7 and a pump 8 are provided as a refrigerant circulating means and are connected to a cooling panel 4 in the tank 1 via a cooling pipe 9 to form a cooling system. There is. In this cooling system, a fluorocarbon 10 having a high dielectric strength is used as a refrigerant, and the fluorocarbon 10 is sent to a cooling panel 4 incorporated in the foil winding 3 to generate heat in the foil winding 3. The loss is cooled by utilizing the latent heat of the fluorocarbon 10. In this case, the pressure of the fluorocarbon 10 is
The pressure of the SF ₆ gas 5 in the tank 1 is adjusted to be equal by the same pressure device 11.

The foil winding 3 in the tank 1 is composed of the conductor 1
It is drawn into the cable termination box 13 via 2 and is further connected to the cable 15 via the cable cone 14. The SF ₆ gas 5 is also enclosed in the cable termination box 13, and is separated from the SF ₆ gas 5 in the tank 1 by the insulating spacer 16.

[0006]

By the way, in the conventional foil wound transformer as described above, fluorocarbons having high dielectric strength are used as the refrigerant. In this type of refrigerant, the specific heat is Since it is slightly lower than the above and easily adsorbs gas, it has a drawback that flushing at the time of assembly and handling at the time of injection are difficult, and it cannot be easily obtained.
Moreover, the price of fluorocarbons is about 20 times higher than that of insulating oil, and pumps and coolers are also expensive.
Since fluorocarbons must be used exclusively from the viewpoint of abrasion resistance and permeability, there is a problem in the economics of the cooling system. In addition, if you find a problem with these devices by using a pump or cooler exclusively for fluorocarbons in this way, it will take a lot of time to solve the problem or prepare a substitute. However, there is a disadvantage that the maintenance time becomes long. On the other hand, when SF ₆ gas is used as the insulating medium, it is necessary to fill the tank with high pressure SF ₆ gas, and therefore it is necessary to use a pressure vessel capable of withstanding high pressure as a tank. This leads to an increase in the cost of vessels.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and its purpose is to:
(EN) Provided is a foil wound transformer which can contribute to improvement of cooling performance, easy handling of a refrigerant, and improvement of economical efficiency of a cooling system, and which is easy to maintain.

[0008]

In a foil winding transformer according to the present invention, a foil winding wound by stacking a conductive sheet and an insulating sheet is enclosed in a tank together with an insulating medium, and the foil winding in the tank is wound. Cooling means is arranged inside or outside the wire, and in a foil winding transformer equipped with a cooling system for introducing a refrigerant into the cooling means from a refrigerant circulating means provided outside the tank through a cooling pipe, the pure refrigerant is used as the refrigerant. It is characterized in that pure water conversion means for maintaining the pure water state of the refrigerant introduced into the cooling means is provided in a part of the tank of the cooling system using water. Further, preferably, a gel insulator is used as the insulating medium. Further, the cooling means is generally a cooling panel built in the foil winding, and the pure water converting means generally uses an ion exchange resin.

[0009]

The operation of the present invention having the above construction is as follows. First, by using pure water as the refrigerant, the latent heat of pure water is larger than that of fluorocarbons, so that the cooling performance can be improved. Further, since the pure water state of the refrigerant is maintained by the pure water converting means and the pure water can be always introduced into the cooling means such as the cooling panel, the insulation performance is not deteriorated due to the ionization of the pure water.

Further, when pure water is used as the refrigerant as described above, a standard pump or cooler can be used for the cooling system, and the cooling system can be flushed and the refrigerant can be easily handled during assembly. Furthermore, when a gel-like insulator is used as the insulating medium, the gel-like insulator has a high sealing property, so that it is possible to use an ordinary tank that is not a pressure vessel, and is a refrigerant by any chance. Even if pure water leaks, the insulation performance of the winding is not deteriorated.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of embodiments of the foil winding transformer according to the present invention will be described below with reference to FIGS.

First, FIGS. 1 to 3 are views showing a typical embodiment of a foil winding transformer according to the present invention. FIG. 1 is a side sectional view and FIG. 2 is a sectional view showing a winding structure. 3 is a cross-sectional view showing an end portion of a winding wire corresponding to the portion A in FIG. In addition,
The same parts as those of the prior art shown in FIG.
The description is omitted.

That is, as shown in FIG. 1, in a normal tank 21 which is not a pressure vessel, a transformer contents including an iron core 2, a foil winding 3 and a cooling panel 4 built in the foil winding At the same time, a gel insulator 22 having a high sealing performance is enclosed as an insulating medium for ensuring the ground insulating performance. Further, outside the tank 21, a standard cooler 23 and a pump 24 are provided as refrigerant circulation means, and are connected to the cooling panel 4 in the tank 21 via a cooling pipe 9 to form a cooling system. .. In this cooling system, pure water 25 is used as the refrigerant. further,
An ion exchange resin 26 that neutralizes the ionized pure water 25 is arranged at the refrigerant introduction portion from the pump 24 to the cooling panel 4 and the refrigerant introduction portion from the cooling panel 4 to the cooler 23. A filling 27 is arranged at a position in the tank 21 that is not so important in terms of insulation, thereby reducing the amount of the gel-like insulation 22.

On the other hand, as shown in FIG.
Inner circumference low-voltage foil winding 3a and outer circumference high-voltage foil winding 3b
Each of the windings 3a and 3b is formed around the winding insulating cylinder 28, and the duct piece 2
It is arranged through 9. And each winding 3a, 3b
As shown in FIG. 3, a conductor sheet 30 and an insulating sheet 31 wider than the conductor sheet 30 are stacked and wound.
The winding end padding 32 is inserted between the protruding portions of the insulating sheet 31 from the conductor sheet 30. In the figure, 4a is a header of the cooling panel 4, and corresponds to a connecting portion between the cooling panel 4 and the cooling pipe 9.

In the present embodiment having the above-mentioned structure, since the pure water 25, which has a larger latent heat than fluorocarbons, is used as the refrigerant, the cooling performance can be improved as compared with the above-mentioned prior art. And the cooling panel 4
By providing the ion exchange resin 26 at the inlet and outlet of the refrigerant to and from the cooling panel 4, the pure water 25 ionized by the cooling panel 4 or the cooler 23 or the pump 24 can be neutralized at all times. There is no problem that the insulation performance is deteriorated by the ionization of 25.

Further, as a result of using pure water 25 as the refrigerant, the cooler and pump used in the cooling system do not need to be dedicated to the fluorocarbons used conventionally, and the standard cooler 23 is used. A pump 24 can be used. Furthermore, since the gel-like insulator 22 having a high sealing property is used as the insulating medium, the normal tank 21 can be used as the tank instead of the pressure container.

As described above, in this embodiment, by using pure water as the refrigerant of the foil wound transformer, the cooling performance can be improved, and the flushing at the time of assembly and the handling at the time of injecting the refrigerant become easy. , Its easy to obtain.
By using pure water like this, a standard pump or cooler can be used for the cooling system, so that the cost of pure water is low and the economic efficiency of the cooling system is improved. It becomes easier to secure and maintain alternative products in. Furthermore, in this embodiment, since the gel-like insulator is used as the insulating medium, a normal tank can be used,
From this point as well, the economical efficiency of the entire transformer can be improved.

Next, FIG. 4 is a sectional view showing another embodiment of the foil winding transformer according to the present invention. In this embodiment, in the introduction portion of the refrigerant from the pump 24 to the cooling panel 4,
Two systems of cooling pipes 9a and 9b are provided, and
An ion exchange resin 26 is attached. Then, the valve 3 is provided at two positions before and after the ion exchange resin 26 of these two systems.
3 are provided respectively, and by opening and closing these valves 33, the pure water 25 can be switched so as to flow through only one of the systems.

With such a configuration, the ion exchange resin 2 to be replaced when exchanging the ion exchange resin 26
The ion exchange resin 26 can be replaced without stopping the operation of the transformer by closing the piping system 6 and flowing pure water 25 only into the piping system of the other ion exchange resin 26. In addition to being easy, a highly reliable transformer can be obtained without lowering the dielectric strength of pure water.

The present invention is not limited to the above-mentioned embodiment. For example, as another embodiment, the gel-like insulator is filled only in the winding end portion, and the ground insulation is SF.
It is also possible to use ₆ gases. In this case, as in the case of the above-described embodiment, it is possible to prevent the deionized water, which is the refrigerant, from leaking to the charging portion, and prevent the insulation performance from being degraded. Further, the present invention provides an insulating medium other than a gelled insulating medium, that is, an insulating gas such as SF ₆ gas, an insulating liquid such as insulating oil, and a variety of insulating media such as mold insulating with a solid insulator. It is applicable to all used foil wound transformers.

On the other hand, in the cooling system, the positions and the number of the ion exchange resins to be provided can be appropriately selected, and various means other than the ion exchange resin can be used as the pure water converting means. .. Also, as the cooling means provided in the tank, various means other than the cooling panel can be used. For example, a cooling pipe is used to wind the winding in the winding or to wind the winding around the outer circumference of the winding. The configuration can be freely changed, such as by arranging in. Moreover, maintenance can be facilitated by forming the cooling system partially or entirely of a transparent material so that the state of the refrigerant can be monitored from the outside. Further, by constructing the cooling pipe with an insulator, the electric field applied to the pure water in the pipe portion in the tank can be significantly relaxed, and the insulation reliability of the cooling system can be further improved.

[0022]

As described above, according to the present invention, by providing the pure water converting means such as the ion exchange resin in the cooling system of the foil wound transformer, the insulation performance is deteriorated by the ionization of pure water. Since pure water can be used as a refrigerant without any need, a foil wound transformer that can contribute to improved cooling performance, easier refrigerant handling, and improved cooling system economics and is easy to maintain is provided. can do.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a typical embodiment of a foil winding transformer according to the present invention.

FIG. 2 is a cross-sectional view showing the structure of the winding wire shown in FIG.

FIG. 3 is a cross-sectional view showing an end of a winding wire corresponding to part A in FIG.

FIG. 4 is a side sectional view showing another embodiment of the foil winding transformer according to the present invention.

FIG. 5 is a side sectional view showing an example of a conventional foil winding transformer.

[Explanation of symbols]

1, 21 ... tank 2 ... core 3 ... Hakumakimakisen 3a ... low Hakumakimakisen 3b ... pressure Hakumakimakisen 4 ... cooling panel 4a ... header 5 ... SF ₆ gas 6 ... shield 7,23 ... cooler 8 , 24 ... Pumps 9, 9a, 9b ... Cooling piping 10 ... Fluorocarbon 11 ... Equalizer 12 ... Conductor 13 ... Cable termination box 14 ... Cable cone 15 ... Cable 16 ... Insulating spacer 22 ... Gel insulator 25 ... Pure water 26 ... Ion exchange resin 27 ... Filling 28 ... Winding insulating cylinder 29 ... Duct piece 30 ... Conductor sheet 31 ... Insulating sheet 32 ... Winding end filling 33 ... Valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Murase 2-1, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Stock company Toshiba Hamakawasaki factory

Claims (2)

[Claims] 1. A foil winding wound by stacking a conductor sheet and an insulating sheet together with an insulating medium is enclosed in a tank, and cooling means is arranged inside or outside the foil winding in the tank. In a foil wound transformer provided with a cooling system for introducing a refrigerant into a cooling means from a refrigerant circulating means provided outside through a cooling pipe, pure water is used as the refrigerant, and a foil outside the tank of the cooling system is used. A foil winding transformer, characterized in that a pure water converting means for maintaining the pure water state of the refrigerant introduced into the cooling means is provided in the section. 2. The foil wound transformer according to claim 1, wherein a gel-like insulator is used as the insulating medium.