JPS58112313A - Transformer - Google Patents

Abstract

PURPOSE:To reduce thickness of a lead and decrease local expansion of the winding, by a method wherein lead wires are drawn from upper and lower ends of a lead installed at the winding end of a metal sheet, and current is distributed in upper and lower parts. CONSTITUTION:Lead wires 16a, 16b are connected to each other and made one lead wire which is connected to a bushing 20. Other lead wires 17a, 17b are drawn from upper and lower ends of a lead installed at the winding finishing end of a metal sheet 2 and further connected commonly to a bushing 21. Current flowing in the lead 24 is distributed to upper and lower parts of the lead 24 thereby the cross-section of the lead 24 may be reduced.

Description

[Detailed description of the invention] Technical field of invention The present invention relates to a transformer using foil-wound windings.

Technical Background of the Invention A transformer using a foil-wound wire formed by overlapping a metal sheet and an insulating sheet has a characteristic that the winding has a good space factor and can be made smaller and lighter. This foil-wound transformer has already been put to practical use in small-capacity transformers with relatively low voltages of several ffA or several hundred ffA@degrees, and has recently been put into practical use in higher-voltage, large-capacity transformers such as 27511 fV, 300
Research is being conducted to expand the application to MYM transformers, but since cooling the windings is a major problem in high voltage, large capacity transformers, it is recommended to use cooling within the foil windings for high voltage, large capacity transformers. A transformer is being considered that employs a so-called heat pipe cooling method, in which heat generated from winding loss is directly cooled by incorporating a cooling duct and passing a refrigerant with excellent insulation properties through this cooling duct.

Figure 1 shows what is conventionally considered as a foil-wound transformer with such a cooling method.
The low voltage 'Ih*s wound around the outside of the insulating cylinder 7 fitted into the
tt is a high-voltage winding wound on the outside of an insulating purrier 1 formed on the outside of a low-voltage 11 kft 84, and these windings 4 and 5 are foil windings in which a metal sheet 1 and an insulating sheet 1 are overlapped and wound. It is considered to be a winding wire. 6 is foil-wound winding 4. This cooling duct C is made of metal such as stainless steel and is built into each suitable place in each coil.This cooling duct C is wound together with the permanent winding. It is designed so that refrigerants such as 113 and Fe12 can pass through it. j Hatake is an inlet side liquid guide pipe that guides the refrigerant circulating through the cooling duct 8, 9111 is also an outlet side liquid guide pipe), and an inlet side liquid guide pipe 9m is a pipe below the winding 4.5. and is connected to the lower end of the cooling duct 6 via a liquid guide pipe 10a. In addition, the outlet side liquid guiding pipe #b has winding 4. It is piped above l, and the liquid guide pipe job
is connected to the upper end of the cooling duct σ through. The liquid guide pipes #a and 9b are made of metal such as stainless steel, but the liquid guide pipes 10m and 10b are insulated pipes made of Teflon (tetrafluoroethylene resin), etc., and are connected to the cooling Dugtro and the liquid guide pipe 9@ , 9b), the liquid guide pipe 9m and 9b are electrically connected to the earth potential of the tank, and the cooling duct 6 is built into the winding 4.5. The upper winding is electrically connected to the same potential as the adjacent winding.

The refrigerant supplied to the cooling duct 6 cools the windings by passing through the duct and absorbing the heat generated in the windings with the latent heat of evaporation of the refrigerant. The refrigerant is cooled and condensed by water cooling, and the liquefied refrigerant enters the refrigerant tank 1z and is sent to the cooling duct g by the pump 13.

Also, there is insulating oil or SF inside the tank.

An insulating medium such as gas is filled in, and the insulation of each part of the winding 4.5 is ensured by this insulating medium.

In this cooling type transformer, the circulation circuit through which the refrigerant for cooling flows and the insulating medium for insulation are completely separated. For this reason, this type of foil-wound transformer is particularly called a separate foil-wound transformer.

This cooling type transformer utilizes the latent heat of vaporization of the refrigerant, so it can be expected to have excellent cooling characteristics, making it a promising choice for high voltage, large capacity transformers.

On the other hand, in FIG. 1, 14.15 is the lead wire of the low voltage winding 4, 16.11 is the lead wire of the high voltage winding 5, and these lead wires 14.15 are the lead wires of the high voltage winding 5. I.S.

16.11 are each led out from the upper end of the winding 4.5 and connected to the bushing 1@, 19°20.11 on the tank. Note that the main lead wires may be drawn out from the lower end of the winding, but in any case, in conventional transformers, each lead wire is drawn out from one end of the winding. Marshal each lead wire 14. Is, 16.11 are lead conductors 22, 23, such as aluminum plates, which are attached to the winding start end and winding end of the metal sheet 2 of each winding 4.5, respectively, as shown in FIG. It is connected to the end of 24°j5 and drawn out from the end of this lead conductor.

Problems with the Background Art However, in conventional transformers, the lead-out conductor XI
, 23, 24, and 25 have to be made large enough to correspond to the amount of current flowing through the gold mine of the metal sheet 2, resulting in the following problems. That is, for example, if the thickness of the metal sheet is 0.4 m and the width is 1500 m, the cross-sectional area of the metal sheet in the width direction is 6-.

In order to cause a current to flow through the metal sheet through the lead conductor, if the current density of the lead conductor is the same as that of the metal sheet, the cross-sectional area of the lead conductor must be the same as the cross-sectional area of the metal sheet in the width direction. Therefore, even if the lead conductor is 100 mm wide, the thickness of the lead conductor will be as much as g m lc. Therefore, in the conventional transformer, the thickness of the lead conductors 21, 23, 14, 25 is quite thick, and among them, the lead conductors zz, 2
Since the lead conductors 11, 23, and 24 on the inner side of the high-voltage winding 5 are inside the windings, if these lead conductors 11, 23, and 24 are thick, the windings 4.5 and the insulating purrier 8 wound on the outside of the lead conductors 11, 23, and 24 are thick.
The part corresponding to lead conductor 1:l, 23.24 is the second
As shown in the figure, the winding 4 bulges outward.
Since local stress is applied to , 5, mechanical reliability is also reduced by 1.
It wasn't.

Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances, and its object is to reduce the thickness of the lead conductor provided at the end of the winding of the metal sheet, thereby reducing the thickness of the lead conductor provided at the end of the winding. The purpose of the present invention is to provide a transformer with reduced mechanical bulges, reduced stress on the windings, and improved mechanical reliability.
Summary of the Invention That is, the first invention of the present invention is to draw out lead wires from both the upper and lower ends of the lead-out conductor provided at the winding end of the assigned sheet, so that the current flowing through the lead-out conductor is divided into upper and lower ends. With this configuration, the cross-sectional area of the lead-out conductor can be reduced, and therefore its thickness can be reduced.

Moreover, the second invention of the present invention is the first invention,
It is characterized by the provision of a current balance circuit that balances the current flowing through both lead wires pulled out from the upper and lower sets of lead conductors, and with this configuration, the thickness of the lead conductors can be reduced compared to the conventional one. It can be reduced by half compared to

Embodiment of the Invention An embodiment of the invention will be described below with reference to FIGS. 3 and 4. Components in the figure that are the same as those shown in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted.

In FIG. 3, 16 m and Jib are lead wires 77a drawn out from the inner peripheral side of the high voltage winding 5.

Ifrb is a lead wire pulled out from the outer peripheral side of the high-voltage winding, and the inner lead wires 16h and jlb are the lead wires 16h and jlb of the lead conductor 24 provided at the winding start end of the metal sheet 2, as shown in FIG. They are connected to the upper and lower ends of the winding 5, respectively, and are drawn out to the upper and lower ends of the winding 5. And this both lead wires Jim, 1
6b are connected to each other to form a single lead wire and are connected to the bushing 20, and the lead wires 77m and JFb on the outer periphery are also connected to the upper and lower ends of the lead conductor provided at the end of the winding of the metal sheet 2. It is pulled out from the bushing 21 and is connected to the bushing 21 through a common connection.

Therefore, in this transformer, the current flowing through the lead conductor z4 is not divided into upper and lower parts of the lead conductor 24, and therefore the cross-sectional area of the lead conductor 24 can be reduced, so that its thickness can be reduced. It can be made thinner, thereby reducing the local bulge of the winding 5, reducing stress on the winding 5, and increasing mechanical reliability.

On the other hand, in FIGS. 3 and 4, 2C is a current balance circuit that balances the two lead wires 16m and 4fi flowing through the inner lead wires 16m and jib, and this current balance circuit 26 is used to balance the two lead wires lj&.

A current transformer in each of 16b! 7m and 2Fb, and these two current transformers J7a and j7b are cross-connected. This current balance circuit is connected to both outer lead wires 1
1m and 17b are also provided.

In this way, both wires are 16m long.

By balancing the current flowing through the lead conductor 24, the current flowing through the upper half of the lead conductor 24 and the current flowing through the lower half can be equal to the current flowing through the metal sheet. The thickness can be halved compared to conventional ones.

In the above embodiment, the lead wires on the outer circumferential side of the high voltage winding 5 are also drawn out from both the upper and lower ends as two lead wires.
Even if the lead conductor on the outer circumferential side of the high-voltage winding @S is thick, it has no effect on the bulge of the winding 5, so the lead wire on the outer circumferential side may be drawn out as one as in the conventional case. Further, in the above embodiment, only the lead wires of the high voltage winding 5 are drawn out from above and below, but if the lead wires on the inner and outer peripheral sides of the low voltage winding 4 are also drawn out from above and below, the lead wires inside and outside of the low voltage winding 4 can also be made thinner. Therefore, the local bulge of the winding 4.5 can be further reduced and reliability can be further increased.

Effects of the Invention Since the transformer of the present invention has a queen-like configuration,
It is possible to reduce the thickness of the lead conductor provided at the winding end of the metal sheet, thereby reducing the local bulge of the winding, reducing the stress applied to the winding, and improving mechanical reliability. I can do it.

[Brief explanation of the drawing]

1 and 2 are a longitudinal sectional view and a plan view of a winding of a conventional transformer, and FIGS. 3 and 4 are a longitudinal sectional view and a schematic diagram illustrating an embodiment of the present invention. 2... Metal sheet, 1... Insulating sheet, 4... Low voltage winding, 5... High voltage winding, 16*, 16b, 11m. 1”lb...Lead wire, 24...Output conductor, 26
...Current balance circuit, 21m, 27b...Current transformer. Applicant's agent Patent attorney Suzue Takehiko I2vlJ

Claims (3)

[Claims] (1) A transformer using a foil-wound wire made by overlapping and wrapping a metal sheet and an insulating sheet, characterized in that lead wires are drawn out from both the upper and lower ends of a lead conductor provided at the winding end of the metal sheet. transformer. (2) In a transformer using a foil-wound wire made by overlapping a metal sheet and an insulating sheet, lead wires are pulled out from both the upper and lower ends of the lead conductor provided at the winding end of the metal sheet, and both leads are A transformer characterized by being equipped with a current balance circuit that balances the current flowing through the lines. (3) The transformer according to claim (2), wherein the current balance circuit is formed by cross-connecting two current transformers respectively interposed between both lead wires.