JPS58219715A - Stationary induction electric apparatus - Google Patents

Abstract

PURPOSE:To effect an excellent cooling and prevent any leakage of coolant, by forming a cooling duct from a plurality of thin tubes arranged in a belt-like shape, and spirally disposing the cooling duct between the adjacent layers of a metal foil along the winding direction thereof. CONSTITUTION:A belt-like cooling duct 21 constituted by a plurality of thin plastic tubes 22 is spirally disposed between the adjacent layers of a metal foil 2 constituting a foil winding. The winding starting and terminating ends of each of the thin plastic tubes 22 constituting the cooling duct 21 also serve as insulating pipes 23 as they are, respectively, and are joined to a coolant collecting pipe. Since the duct 21 is wound so as to be in close contact with each layer of the foil 2, cooling is uniformly effected. In addition, since the winding starting and terminating ends of each thin tube 22 also serve as the insulating pipes 23 and can be joined to the coolant collecting pipe 10 as they are, the danger of leakage of the coolant is eliminated.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a stationary induction electric generator having a foil-wound wire formed by overlapping metal foil and an insulating sheet, and having a cooling duct built into the winding. Regarding equipment.

[Technical Background of the Invention] Stationary induction electrical equipment having foil-wound windings, such as foil-wound transformers, have a good space factor and are therefore characterized by being able to be made smaller and lighter. It has already been put into practical use in relatively low-voltage, small-capacity transformers with a capacity of several 100 KVA.

Recently, in view of its excellent advantages, research has been conducted to expand its application to higher voltage and larger capacity transformers, such as 275KV and 300MVA, but the biggest problem in practical application is:
The question is how to improve cooling capacity and provide high insulation capacity to the windings. As described above, there are various problems in the practical application of high-voltage, large-capacity transformers using foil-wound windings, but as foil-wound transformers that are already known and have been studied,
There is a so-called heat pipe type in which a cooling duct is built into the winding, and a refrigerant with excellent insulating properties is pumped in and circulated to directly cool the heat generated from winding loss.

Figure 1 shows the structure of this heat pipe type foil-wound transformer.

A metal foil 2 is wound many times around the outer periphery of the leg portion 1 of the iron core with a sheet-like insulation @3 interposed therebetween to form a low voltage winding 4 and a high voltage winding 5. A hollow metal cooling duct 6 is built in between these low and high voltage windings 4.5. This cooling duct d has a double cylindrical shape or a divided double cylindrical shape along the winding direction of the winding wire, and inside the thin gap that is the hollow part, Freon R-113 and 70 Rinato FC
A refrigerant 7 such as 75 is sealed. This refrigerant is circulated through an insulated pipe 9 connected to the cooling duct 6 by a pump 8 of a cooling device installed outside the transformer, and the heat generated in the winding is removed by the latent heat of evaporation of the refrigerant. is collected by a liquid collection pipe 10 through an insulated pipe 9,
It leads to a cooling device installed above the windings. Then, it is cooled by a water cooling pipe 12 in a condenser 11 of a cold enclosure device,
It seems to be condensing again. The condensed and liquefied cold 17 is stored in a refrigerant tank 13 provided below the winding, and is sent again to the cooling duct 6 inside the winding by the pump 8.

The main body of the foil-wound transformer, which is provided with a circulation circuit for the refrigerant 7 in this manner, is housed and sealed in a tank 15 together with an insulating medium 14 containing insulating oil or SF6 gas. In this case, the liquid collecting pipe 10 made of metal such as stainless steel is connected to the earth potential of the tank 15, etc., and the cooling duct 6 is connected to the winding 4.
．． 5, it is electrically connected to the same potential as the adjacent winding.

In the transformer having the structure as explained above, the refrigerant 7 for cooling and the insulating medium 14 for insulation are completely liquid-tightly distributed in ml.
(separate). For this reason, this type of foil-wound transformer is particularly called a separate type transformer.

[Problems with the background technology] Since the transformer of this method uses the latent heat of vaporization of the refrigerant,
Since it can be expected to have excellent cooling characteristics, it is promising for large capacity transformers.

However, the conventional separate type transformer as shown in FIG. 1 has the following problems.

That is, a power transformer is generally required to have an operating life of 30 years, but it is extremely difficult to prevent material corrosion or cracks from occurring over such a long period of time, resulting in refrigerant leakage.

Most leaks are very small, but gradually the refrigerant 7 in the refrigerant tank 13 leaks into the transformer tank 15, causing a shortage of refrigerant in the circulation system and insufficient cooling capacity. When considering the reliability of this separate type transformer, causing A-bar heat in the transformer is the biggest problem. Therefore, the cooling duct 6 and the liquid guide pipe 10 are manufactured using stainless steel or copper materials under quality control to prevent the refrigerant 7 from leaking, and the joints with the insulating pipe 9 are also joined to prevent leakage. A method is needed.

By the way, the conventionally known cooling duct 6 has a cylindrical shape as shown in Fig. 2, and is made by stacking two metal cylinders and joining them with a gap maintained between them. °
It is something to do. Furthermore, as shown in FIG. 3, a plurality of cooling ducts 6 each having a cylindrical shape divided into sections may be arranged. As shown in the cross section shown in FIG. 4, this cooling duct 6 has a circular upper edge and a lower edge, and an outlet pipe 16 for connecting to the edge pipe 9 is provided at this portion. There is.

However, as is clear from the figure, the manufacturing of the cooling duct 6 requires
It is very difficult to mold each end into a circular shape, and therefore there are many joints, which requires a considerable amount of manufacturing time and there is concern about leakage from the joints.

Furthermore, in order to incorporate the cooling duct 6 between the windings of the foil-wound winding, the cooling duct 6 is required to be easily in close contact with the winding. However, as is clear from the shapes shown in Figures 2 to 4, the circular parts at the upper and lower edges have high rigidity, so it is extremely difficult to completely attach them to the windings, and it is difficult to cool them evenly. There was a drawback.

Furthermore, since conventional cooling ducts are made of metal and are joined and formed by welding, they generally require a lot of time and effort to manufacture and have the drawbacks of being heavy.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and its objects are to facilitate the manufacture of a cooling duct, to have extremely few joints, and to eliminate the risk of refrigerant leakage. It is an object of the present invention to provide a separate type stationary induction electric device which can be easily brought into close contact with windings and evenly cooled.

[Summary of the Invention] The stationary induction electric device of the present invention includes a cooling duct disposed within a foil-wound winding, which is formed from a plurality of thin tubes arranged in a strip shape,
Moreover, this cooling duct is spirally arranged between each layer of metal foil along the winding direction.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to FIG.

In this embodiment, the cooling duct 21 includes a plurality of thin tubes 2
2 are arranged in a strip shape. This capillary tube 22 is made, for example, from a plastic material with good thermal conductivity. These multiple thin tubes 2
A belt-shaped cooling duct 21 consisting of 2 is spirally arranged at each gate of the metal foil 2 constituting the foil-wound winding. That is,
It is arranged from the inner four layers to the outer layer along the winding direction of the metal foil 2, and the winding position is shifted from one end (upper end) to the other end (lower end) in the width direction of the metal foil. It is wrapped around. The beginning and end ends of the winding of each plastic thin tube 22 constituting the cooling duct 21 also function as an insulating pipe 23 and are joined to the liquid collecting pipe.

In this embodiment, in order to form the cooling duct 21, when the metal foil 2 is wound around the outer periphery of the leg part 1 of the iron core via the sheet-like insulation @ 3, the cooling duct 21 is wound at the same time. Moreover, the winding of the cooling duct 21 is formed in a spiral shape as a whole while shifting its position downward.

According to this embodiment, the spiral cooling duct 21 is composed of a plurality of plastic thin tubes 22, so the strip-shaped cooling duct 21 is highly flexible as a whole, and is lightweight and easy to work with. Since it has good properties, it is easy to manufacture. In addition, this cooling duct 21 is highly flexible and has a strip shape in which the thin tubes 22 are arranged vertically, so it can be easily wrapped closely around the metal foil 2 that is the winding. be. Furthermore, since the cooling duct 21 is tightly wound around each layer of the metal foil 2, cooling is performed more evenly than in the conventional cylindrical cooling duct 21. In addition, the ends at the beginning and end of the winding of the thin tube 22 also serve as the insulating pipe 23, and can be directly connected to the liquid collecting pipe 1o, so that the cooling duct 21 and the separate insulating pipe 9 can be connected to each other as in the conventional example. This is not necessary and therefore eliminates the risk of refrigerant leakage. Furthermore, the thin tube 22 is made of plastic, which has the advantage of high chemical resistance and mechanical strength.

In this embodiment, the thin tube 22 is made of plastic, but instead of this, a metal thin tube that is flexible enough to be wrapped can also be used. Also,
In this embodiment, the cooling duct is wound from the upper part of the winding to the lower part, but in other embodiments, the cooling duct may be wound from the lower part to the upper part to obtain a better result. Alternatively, a combination of both may be used. Furthermore, the present invention is not limited to foil-wound transformers, but can also be applied to other stationary induction electrical equipment using foil-wound wires.

[Effects of the Invention] As described above, the cooling duct used in the present invention is formed from a plurality of thin tubes arranged in a strip shape, and the cooling duct is arranged between each layer of metal foil along the winding direction. Because it is arranged in a spiral, there is no need to worry about refrigerant leaking, and it also allows for easy contact with the windings, allowing for even cooling of the windings.
Moreover, it is easy to manufacture. Therefore, according to the present invention, it is possible to provide a highly reliable stationary induction electric device in which windings are cooled well and there is no leakage of refrigerant.

[Brief explanation of the drawing]

Figure 1 is a right sectional view of a conventional separate transformer;
3 and 3 are respectively perspective views showing conventional cooling ducts, FIG. 4 is a sectional view taken along the line A-A in FIGS. 2 and 3, and FIG. 5 is an embodiment of the static induction electrical equipment of the present invention. The right enlarged sectional view shown in FIG. 6 is a sectional view of the cooling duct portion in FIG. DESCRIPTION OF SYMBOLS 1... Leg of iron core, 2... Metal foil, 3... Sheet-like insulating material, 4... Low voltage winding, 5... High voltage winding, 6...
...Cooling duct, 7.Refrigerant, 8.Pump, 9.
... Insulating vibe, 10... Liquid collecting pipe, 11... Condenser, 12... Water cooling pipe, 13... Refrigerant tank, 14...
... Insulating medium, 15 ... Tank, 16 ... Outlet pipe, 21 ... Cooling duct, 22 ... Thin tube, 23 ...
...Insulated 6-ib. 7317 Representative Patent Attorney Kensuke Norichika (and 1 other person) s 1 Figure 2 Figure 5

Claims (1)

[Claims] (1) In a stationary induction electrical equipment that has a built-in cooling duct between the foil-wound windings made by winding metal foil with a sheet-like insulating material interposed in between, and performs cooling by circulating a cooling medium through the cooling duct, the above-mentioned cooling The duct is formed by arranging a plurality of flexible thin tubes into a single strip, and this cooling duct is arranged on a spiral pile between each layer of metal foil along the winding direction. Stationary induction electrical equipment. (2) The stationary induction electric device according to claim 1, wherein the plurality of thin tubes are made of plastic.