JPS63196020A - Foil wound transformer - Google Patents

Abstract

PURPOSE:To largely improve the strength of a foil wound transformer against a short-circuit defect by forming a recess at the side of a cooling panel end to which a short-circuit mechanical force is applied, and disposing a reinforcing member to be engaged with the recess at a gap formed between the panels, thereby preventing a metal sheet from buckling. CONSTITUTION:Recesses 21, 26 are formed at the side faces of cooling panels 20a-20d, 25a-25d multiply divided to be contained in a winding and to which short-circuit mechanical force is applied, and reinforcing members 23, 24, 28, 29 engaged with the recesses 21, 26 for reinforcing gaps 22, 27 are arranged in gaps 22, 27 formed between the panels 20a-20d, 25a-25d disposed on the same circumference and on the crossover sections of a metal sheet 2. Accordingly, even if the gaps 22, 27 between the panels 20a-20d, 25a-25d are eliminated and a short-circuit force is applied to windings, the sheet 2 is not buckled. Thus, a foil wound transformer in which the strength against a short-circuit defect can be largely improved with high reliability can be obtained.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention is a foil winding in which a cooling panel is built into the foil winding made by overlapping and winding a metal sheet and an insulating sheet. It concerns transformers.

(Prior art) Foil-wound transformers have a good winding space factor (they are small and lightweight). They are already practical for small capacity transformers with relatively low voltages of several KV or several hundred KVA. In recent years, in view of its excellent advantages, research has been carried out to expand its application to higher voltage and larger capacity transformers, such as 275KV and 300MVA class transformers.However, the biggest technical problem is how to improve the cooling capacity. The two issues are whether the windings can be improved and have a high insulation capacity, and whether they can withstand the radial mechanical force in the event of a short circuit accident. Although it has not been put to practical use, as shown in Figure 3, a cooling panel is built into the winding, and a refrigerant with excellent insulation properties is fed into this cooling panel, and the heat generated from the winding loss is absorbed into the evaporation of the refrigerant. A so-called heat pipe type foil-wound transformer, which uses latent heat for cooling, is promising.

That is, in this foil-wound transformer, a low-voltage winding 4 and a high-voltage winding 5 formed by overlapping metal sheets 2 and insulating sheets 3 are wound around a leg 1 of an iron core, and the highest voltage winding 5 is High voltage shields are provided at the upper and lower outer ends. Furthermore, a hollow cooling panel 6 extending in the axial direction is built into the low-voltage winding 4 and the high-voltage winding 5.

This cooling panel 6 consists of two metal plates stacked one on top of the other at an appropriate distance, the periphery of which is sealed by welding, etc., and an inlet nozzle for feeding refrigerant is placed at the lower end, and an outlet nozzle for sending out the refrigerant is arranged at the upper end. be.

A refrigerant such as Freon R-113 or Fluorinert FC75 is sealed in the thin gap of the hollow part, and the pump 7
The refrigerant is circulated by the refrigerant, and the heat generated within the windings is absorbed by the latent heat of evaporation of the refrigerant, thereby performing cooling. Further, the refrigerant that has absorbed the heat is sent out to the outside of the winding from the outlet nozzle, and is cooled in a cooler 9 provided outside the tank 8,
A cooling system is constructed in which the pump 7 feeds the air into the windings again.

Note that before the refrigerant is sent into the cooling panel 6, it is once collected in the east liquid pipe 10, but this liquid collection pipe 10 is connected to the tank 8.
The metal sheet 2 is connected to the cooling panel 6 having the same potential through an insulating pipe 11 made of Teflon resin or the like.

In addition, since the cooling panel 6 is built into the winding,
It is electrically connected to the same potential as the adjacent winding. Furthermore, the insulation of each part of the winding is made of SFe sealed in the tank 8.
This is ensured by an insulating gas such as gas.

By the way, the above-mentioned foil-wound transformer uses a thin metal sheet 2.
Since the low voltage winding 4 and the high voltage winding 5 are formed by overlapping and winding the insulating sheet 3, the winding space factor within the core window increases, but on the other hand, there are the following problems. .

That is, the cooling panel 6 inserted into the winding is shown in FIG. As shown, it is divided into multiple parts in the circumferential direction.

However, when an external accident occurs in a foil-wrapped transformer with a built-in cooling panel 6 configured as described above, an excessive short circuit current flows, resulting in a radial short circuit as shown by arrows 12 and 13 in Fig. 3. Mechanical power works.

This short-circuit mechanical force acts toward the center of the winding on the low-voltage winding 4 side, while acting toward the outside of the winding on the high-voltage winding 5 side.

That is, when such a short-circuit mechanical force acts on the low-voltage winding 4 side, the gap formed between the adjacent cooling panels 60 at the crossing portion of the metal sheet 2, as shown in FIG. 4(B). At the portion 14, the metal sheet 2 sometimes buckled in the radial direction.

Furthermore, as shown in FIG. 4(C), even in the gap 15 formed between adjacent cooling panels 6, there is a portion where no cooling panel 6 is disposed, so that the metal sheet 2 Sometimes it buckled.

On the other hand, when the high-voltage winding 5 side is acted upon, the metal sheet 2 may buckle outward in the gap formed between adjacent cooling panels.

As a result, the metal sheet 2 was damaged, electric field concentration occurred, the dielectric strength of the winding was significantly reduced, and the reliability of the foil-wound transformer was significantly impaired.

(Problems to be Solved by the Invention) As described above, in the conventional foil-wound transformer, the winding The metal sheet could buckle due to short-circuit mechanical forces acting in the radial direction.

Therefore, the present invention aims to eliminate the above-mentioned drawbacks, and its purpose is to prevent buckling of the metal sheet even when a short radial mechanical force is applied to the winding, and to significantly increase the strength against short-circuit accidents. An object of the present invention is to provide an improved and highly reliable foil-wound transformer.

[Structure of the Invention (Means for Solving Problems) The foil-wound transformer of the present invention has a recess formed on the side surface to which a short-circuit mechanical force is applied at the end of a multi-divided cooling panel built into the winding. and a supplementary member is provided in the gap formed between the cooling panels arranged on the same circumference and in the crossing portion of the metal sheet, the supplementary member fitting into the recess and filling the gap. be.

(Function) The foil-wound transformer of the present invention has a supplementary member arranged between the cooling panels that fits into the recess formed on the side surface to which the short-circuit mechanical force is applied at the end of the cooling panel and fills the gap between the cooling panels. do,
This eliminates the gaps between the cooling panels and prevents the metal sheet from buckling even when short-circuit mechanical force is applied to the windings.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIGS. 1 and 2. Incidentally, the same members as those of the conventional type shown in FIGS. 3 and 4 are given the same reference numerals, and explanations thereof will be omitted.

Configuration of this embodiment* In this embodiment, as shown in FIG. A depression 21 is formed.

In addition, the gaps 22 formed between the ends of the cooling panels 20a, 20b, 20c, and 20d, which are wound on the same circumference at appropriate intervals, are made of a material with high thermal conductivity. A supplementary member 23 is provided. At both ends of the replenishing member 23, protrusions 23a are formed to fit into the recesses 21 formed at the ends of the cooling panel 20, and the replenishing member 23 has a shape that can compensate for the gap 22.

Further, the supplementary member 24 disposed at the crossing portion of the metal sheet 2 has a protrusion 24a that fits into the recess 21 formed in the cooling panel 20 at only one end thereof, and the other end has a protrusion 24a that fits into the recess 21 formed in the cooling panel 20. It is configured in a shape that allows it to be easily pulled out to the outside of the cooling panel 20.

On the other hand, as shown in FIG. 2 (A>), depressions 26 are formed inside both ends in the circumferential direction of the multi-divided cooling panel 25 disposed on the high voltage winding 5 side. Cooling panels 25a are wound around the same circumference at appropriate intervals.
, 25b, 25G.

A replenishing member 28 made of a material with high thermal conductivity is disposed in the gap 27 formed between the end portions 25d. At both ends of this replenishment member 28, the cooling panel 2
A protrusion 28a that fits into a recess 26 formed at the end of 5
is formed, and is configured in a shape that can compensate for the gap 27.

Roughly speaking, the supplementary member 29 disposed at the crossing portion of the metal sheet 2 has a protrusion 2°9a formed at only one end thereof to fit into the recess 26 formed in the cooling panel 25, and the other end is made of metal. The sheet 2 is configured in such a shape that it is easy to pull out the sheet 2 to the outside of the cooling panel 25.

Note that as the supplementary members 23, 24, 28, 29, a copper plate or the like having high thermal conductivity is used.

Effect of this embodiment* In the foil-wound transformer of this embodiment having such a configuration,
When a short circuit mechanical force 12 occurs on the low voltage winding 4 side, the first
As shown in Figure (A), a force in the radial direction toward the center of the winding is applied to the winding, but as shown in Figure 1 (B), the force applied to the winding is adjacent to each other on the same circumference. In the gap 22 between the cooling panels 20, a supplementary member 2 made of a copper plate or the like is installed.
3, there is no gap between adjacent cooling panels 20, so the metal sheet 2 will not buckle.

Further, as shown in FIG. 1(C), since the supplementary member 24 divided into two parts is provided also at the crossing portion of the metal sheet 2, the replenishment member 24 is disposed at the crossing portion of the metal sheet 2. bending can be prevented.

Moreover, not only is buckling of the metal sheet 2 prevented, but also the gap between adjacent cooling panels is eliminated, so the cooling panel 20 becomes annular, and its strength against short-circuit mechanical force is greatly improved.

Furthermore, replenishment members 23, 24, 28 disposed in the gap
．． Since the cooling panel 29 is made of a highly thermally conductive material such as a copper plate, the thermal conductivity between adjacent cooling panels is very good, and the cooling efficiency of the windings can be improved.

As mentioned above, on the low-voltage winding 4 side, the short-circuit mechanical force 12 acts toward the center of the winding, but on the high-voltage winding 5 side, the short-circuit mechanical force 13 acts as shown in FIG. 2(A). Like,
Works towards the outside of the winding.

In this case as well, as shown in FIGS. 2(B) and 2(C), the recess 26 formed at the end of the cooling panel 25 causes a short-circuit mechanical force 1
3 is formed on the working side, so even if the short-circuit mechanical force 13 acts in the outer circumferential direction, the replenishing members 28 and 29 will not close the cooling panel 25.
The metal sheet 2 can be prevented from buckling by engaging with the metal sheet 2.

*Other Examples Note that the present invention is not limited to the above-mentioned embodiments, and the replenishment member disposed in the gap formed between adjacent cooling panels is provided at the axial end of the cooling panel. They may be disposed over the entire length of the cooling panel, or they may be disposed at appropriate intervals at the ends of the cooling panel.

Further, the supplementary member may be composed of a single member formed to match the entire length of the end of the cooling panel, or a plurality of supplementary members may be used.

[Effects of the Invention] As described above, according to the present invention, a recess is formed on the side on which the short-circuit mechanical force acts on the end of the multi-divided cooling panel built in the winding, and the recess is connected to the recess. By simply disposing a supplementary member with matching protrusions in the gap formed between the cooling panels, the winding can be shortened in the radial direction W! It is possible to provide a highly reliable foil-wound transformer that prevents metal sheets from buckling even when mechanical force is applied, and has significantly improved strength against short-circuit accidents.

[Brief explanation of the drawing]

FIG. 1 shows the low-voltage winding side of an embodiment of the foil-wound transformer of the present invention. 3 shows the high-voltage winding side of an embodiment of the foil-wound transformer of the present invention, (A> is a sectional view, (B) and (C) are enlarged sectional views of the main parts, and FIG. 3 is a conventional foil-wound transformer. FIG. 4 is a cross-sectional view showing the structure of a winding transformer, and FIG. 4 shows a conventional foil-wound transformer, (A> is a cross-sectional view, and (B) and (C) are enlarged cross-sectional views of main parts. ... Legs of iron core, 2... Metal sheet, 3... Insulating sheet, 4... Low voltage winding, 5... High voltage winding, 6...
...Cooling panel, 7...Pump, 8...Tank, 9
... Cooler, 10 ... Liquid collection pipe, 11 ... Insulation pipe, 12 ... Short-circuit mechanical force applied to the low-voltage winding side, 13.
・・Short circuit mechanical force applied to high voltage winding 11g4, 14.15・
... Gap, 20... Cooling panel, 21... Hollow, 22... Gap, 23... Replenishment member, 23a...
・Protrusion, 24...Replenishment member, 24a...Protrusion, 25
... Cooling panel, 26 ... Hollow, 27 ... Gap, 28 ... Replenishment member, 28a ... Projection, 29 ...
- Replenishment member, 29a... protrusion.

Claims (4)

[Claims] (1) A metal sheet and an insulating sheet are layered and wound around the legs of the iron core to form a foil winding, and a cooling panel is divided into multiple parts and built into the foil winding to circulate the refrigerant. In the foil-wound transformer, a depression is formed on the side surface of the end of the cooling panel to which the short-circuit mechanical force is applied, and a depression is formed in the gap formed between the cooling panels arranged on the same circumference and at the crossing part of the metal sheet. . A foil-wound transformer, characterized in that a supplementary member is provided that fits into the recess and fills the gap. (2) The foil-wound transformer according to claim 1, wherein the supplementary member is made of a material with high thermal conductivity. (3) The foil-wound transformer according to claim 1, wherein the supplementary member is disposed over the entire length of the end of the cooling panel. (4) The foil-wound transformer according to claim 1, wherein the supplementary member is arranged at an appropriate interval at an end of the cooling panel.