JPS58219719A - Foil-wound stationary induction electric apparatus - Google Patents

Abstract

PURPOSE:To eliminate the electric field concentration on the lead part of a foil winding and perform an effective securing of a metal foil and sheet insulator, by curving the outermost end part of a foil winding into a tubular shape, and inserting a lead into the tubular curved part thereby to bring the lead in contact with the foil winding. CONSTITUTION:The outermost end part of a metal foil 2 forming a winding is curved outwardly of the winding in the direction opposite to the winding direction of the winding, to form a tubular part 31. In this case, also a sheet insulator 3 wound overlaid on the inner side of the metal foil 2 may be simultaneously curved outwardly of the foil winding. Since the surface of the metal foil is exposed on the inner side of the tubular part 31, a conductor 32 similar to that employed conventionally is inserted into the tubular part 31 to bring the conductor 32 and the metal foil 2 into electrical contact with each other. The part of the conductor 32 projecting from the brim of the metal foil 2, that is, the other end of the conductor 32, is employed as a lead of the winding.

Description

[Detailed description of the invention] [Technical field of the invention]
The present invention relates to a foil-wound stationary induction electric device having a foil winding formed by overlapping and winding a metal foil and an insulating sheet.

TECHNICAL BACKGROUND OF THE INVENTION 1 Foil-wound stationary induction electrical equipment having foil windings, such as foil-wound transformers, have a good space factor, so they can be made smaller and lighter. Several kilovolts and hundreds of kilowatts are already being used in relatively low voltage, small capacity transformers such as VA. Furthermore, recently, in view of its superiority, higher voltage and larger capacity such as 275V, 300MVΔ
Expanding its application to transformers is being researched. Although there are various problems in the practical application of high-voltage, large-capacity transformers using such foil-wound wires, as foil-wound transformers that are already publicly available and are being researched,
There is a so-called heat-eve type in which a cooling duct is built into the winding, and a medium with excellent insulating properties is pumped in and circulated to directly cool down 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 around the outer periphery of the leg portion 1 of the iron core in a number of turns in a number of turns through a sheet-like insulation 3 to form a low-voltage winding 4 and a high-voltage winding 5. A hollow metal cooling duct 6 is built in between the low and high voltage lines 4 and 5. The cooling duct 6 has a cylindrical shape or a divided cylindrical shape extending in the same direction as the winding, and a fan R is provided in the thin gap that is the hollow part of the cooling duct 6.
A refrigerant 7 such as -113 or 70 Linate FC75 is sealed. This refrigerant 7 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 removes the heat generated within the windings with the latent heat of evaporation of the refrigerant. The vapor is collected by a collection tube 10 through an insulated pipe 9 and guided to a cooling system provided above the windings. Then, it is placed in the condenser 11 of the cooling device 85, cooled by the water cooling pipe 12, and condensed again. The condensed and liquefied refrigerant 7 is stored in a refrigerant tank 13 provided below the winding, and is sent again to the cooling duct 6 inside the winding by a pump 8'.

The main body of the foil-wound transformer, which is provided with a circulation circuit for the refrigerant 7 in this way, is equipped with an insulating medium 1 such as insulating oil or S, Fs gas.
4 and are housed and sealed in a tank 15. In this case, the liquid collecting pipe 10 made of metal such as stainless steel is connected to the ground 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 described above, the refrigerant 7 for cooling and the insulating medium 14 for insulation are completely liquid-tightly separated. For this reason, this type of foil-wound transformer is particularly called a separate foil-wound transformer.

[Problem in the background art 1 Since the transformer of this method uses the latent heat of vaporization of the refrigerant,
It is promising for large-capacity transformers because it can be expected to have excellent cooling characteristics.

However, the conventional separate foil-wound transformer as shown in FIG. 1 has the following problems.

That is, in the separate foil-wound transformer, since the insulating medium 14 and the coolant 7 are separated, cooling and insulating the inside of the winding is very easy, and the structure is simple. On the other hand, insulation and structural barriers also pose problems, including the treatment of the outermost ends of the windings, electric field mitigation, and the lead opening structure.

This point will be explained with reference to the structure of a conventional lead outlet shown in FIG. Winding lead 2
1 is connected to the end of the metal foil 2 by soldering, brazing, or the like. At that time, the lead 21 and the metal foil 2
In order to facilitate connection with the metal foil 2, the connecting portion 22 of the lead 21 is formed flat as shown in FIG. 3 before being connected to the metal foil 2. In order to avoid eddy current loss, this lead 21 is generally made of thin wires twisted together to form a single cable. In such a case, even if the lead 21 is stretched flat, electric field concentration will still occur at the connection portion where it is joined to the metal foil 2, so further measures to alleviate the electric field will be required. As described above, the structure of the lead outlet is the part that requires the most man-hours in the manufacturing process of a foil-wound transformer, and is an extremely technically difficult part along with insulation and cooling issues.

In addition, with foil winding, there is a problem with the lead opening structure and it is difficult to fix the final turn of the winding, so conventional methods such as tightening the outermost end with insulating tape have been considered. However, with this method, there is a risk that the entire winding may wobble due to loosening of the tape, or that a local mechanical force is applied to the final turn of the winding, causing deformation of the winding.

Moreover, since the cut portion of the metal foil oozes out at the outermost end of the metal foil that forms the winding, the electric field concentrates in this area.
There was a risk of insulation damage.

[Object of the Invention] The present invention has been made to eliminate the drawbacks of the above-mentioned prior art. Provided is a foil-wrapped stationary induction electric device in which the opening part combines the sheet-like insulating material forming the winding and a fixing structure for the outermost end of the metal foil, and the outermost end can be given mechanical strength. The purpose is to

[Summary of the Invention] The foil-wrapped stationary induction electric device of the present invention has the outermost end of the metal foil forming the winding curved into a cylindrical shape to have an electric field relaxing effect, and a conductor inside the cylindrical portion. The conductor is inserted and brought into contact, and this conductor is used as an output lead for the winding.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIG. Note that the same parts as in FIG. 2 are designated by the same reference numerals, and their explanation will be omitted.

The outermost end of the metal foil 2 forming the winding is curved toward the outside of the winding in the opposite direction to the winding direction of the winding, thereby forming a cylindrical portion 31. At this time, the sheet-shaped insulating material 3 which is wound in an overlapping manner inside the metal foil 2 may also be simultaneously curved toward the outside of the foil winding. Since the surface of the metal foil is exposed on the inner surface of the cylindrical part 31, by inserting the conductor 32 formed by twisting wires together in the same manner as in the past into the cylindrical part 31, the conductor 32 and the metal foil can be connected. 2 are brought into electrical contact. The other end of the conductor 32, that is, the portion protruding from the edge of the metal foil 2 is used as a winding lead.

According to this embodiment as described above, since the outermost end of the metal foil 2 is cylindrical, the cut portion 33 of the metal foil 2 is hidden behind the cylindrical portion 31 formed by the metal foil 2. , the electric field of the cutting section 33 is relaxed by the shielding effect of the cylindrical section 31. Moreover, the conductor 32 inserted into the cylindrical part 31 can be used as a lead-out of the winding wire without the need for special molding or adhesion to connect it to metal foil, so the work required for lead-out is very simple. simplified to. Further, the conductor 32 and the metal foil 2 are connected to the cylindrical part 3.
1, the cylindrical portion 31 protects the joint between the two, and no electric field concentration occurs at the joint.

Furthermore, the metal foil 2 is pressed from the outer periphery by the conductor 32 in the cylindrical part 31, and the cylindrical part also serves as a press for the outermost end of the winding, so the mechanical strength of the winding is increased. It is also possible to prevent the entire winding from loosening.

Note that the present invention is not limited to the illustrated embodiment,
The cylindrical portion 31 can also be formed by curving the outermost end of the metal foil 2 inward. In this case, only the metal foil 2 is bent into a cylindrical shape, and the sheet-like insulating material 3 existing inside the potato remains wound around the outer periphery of the foil winding without being bent.

Furthermore, the present invention can be implemented not only in separate foil-wound transformers but also in other foil-wound stationary induction electrical equipment.

[Effects of the Invention] As explained above, according to the present invention, the outermost end of the foil winding is curved into a cylindrical shape and the lead-out lead is inserted into and brought into contact with the outermost end, so that the lead-out structure is improved. , it is simple and does not cause electric field concentration, and at the same time, the metal foil or sheet insulator at the outermost end of the foil winding is effectively fixed, so it is a foil-wrapped stationary induction electric wire with excellent insulation properties and mechanical performance. We can provide equipment.

[Brief explanation of the drawing]

Fig. 1 is a right sectional view of a heat pipe type foil-wound transformer, which is an example of a conventional foil-wound stationary induction electric device, Fig. 2 is a perspective view showing a conventional lead outlet structure, and Fig. 3 is a lead in Fig. 2. FIG. 4 is a perspective view showing the structure of a lead outlet portion in an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Leg of iron core, 2... Metal foil, 3... Sheet-like insulation material, 4... Low voltage winding, 5... High voltage winding, 6...
...Cooling duct, 7.Refrigerant, 8.Pump, 9.
...Insulated pipe, 10...Liquid collection pipe, 11...Condenser, 12...Water cooler, 13...Refrigerant tank, 14...
...Insulating medium, 15...Tank, 21...Lead,
22... Connection portion, 31... Cylindrical portion, 32... Conductor, 33... Cutting portion. 7311 Representative patent attorney Keisuke Chika (one idiot) Figure 1 Figure 2

Claims (1)

[Claims] In foil-wrapped stationary induction electrical equipment in which metal foil and sheet-like insulating material are layered and wound to form a foil-wrapped pressure wire, the outermost end of the metal foil is curved into a cylindrical shape, and the wire is inserted into this cylindrical portion. A foil-wrapped static induction electrical device characterized by inserting a conductor and bringing it into contact with a metal foil, and using this conductor as an outlet lead for a wound cold wire.
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