JPS62126611A - Foil wound transformer - Google Patents

Abstract

PURPOSE:To manufacture a miniaturized and light-weighted foil wound transformer with high dielectric strength by leading out high voltage lead wire from the highest potential part outside a high voltage winding through the central part of low voltage windings by a method wherein the potential of high voltage winding arranged inside the low voltage windings is raised as near as the outside while the low voltage windings are divided into upper and lower two parts. CONSTITUTION:A high voltage winding 12 comprising an overlapped metallic sheet and an insulating sheet wound around an iron core 2 as well as low voltage windings 5, 11 concentrically wound around the same are sealed up in a grounding tank 1 together with an insulating medium 4. In such a foil wound transformer, the potential of high voltage winding 12 arranged inside the low voltage windings 5, 11 is raised as near as the outside while the low voltage windings 5, 11 are divided into upper and lower two parts to lead out a high voltage lead wire 10 from the highest potential part outside the high voltage winding 12 through the central part of the windings 5, 11. Through these procedures, the distance 15 to tank and the other distance 14 to yoke can be reduced markedly so that the foil wound transformer may be miniaturized thereby light-weighed to reduce the magnetism loss while stabilizing the insulation due to the high potential part not facing to the tank.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a foil-wound transformer, and particularly to an improvement in the insulation structure of a lead extraction portion.

[Technical background of the invention and its problems]

Foil-wound transformers use foil-wound windings that are composed of high-voltage windings and low-voltage windings in which metal sheets and insulating sheets are layered and wound around core legs.

This foil-wound wire has a better space factor than a transformer using a normal winding, so it has the characteristic of being able to be made smaller and lighter.

High-voltage, large-capacity foil-wound transformers are surrounded by insulating gas and housed in a grounded tank. In this configuration,
The lead connected to the high-voltage winding may be drawn out from the center of the winding or from the end of the winding. An example is shown in FIG. The figure shows a cross section of a conventional foil-wound transformer.A low-voltage winding 5 and a high-voltage winding 12, which are made of overlapping metal sheets and insulating sheets, are wound around an iron core 2. , an insulating gas 4 and these are grounded tank 1
covered with The high voltage lead wire of the high voltage winding 12 has a structure 10 drawn out from approximately the center of the high voltage winding 12 and a structure 22 drawn out from the end of the winding. These high voltage leads 1
0.22 is connected to a conduit 7 on the high-pressure equipment side via an insulating spacer 6 provided on the wall of the tank 1.

The above-mentioned two high-voltage lead extraction structures each had the following drawbacks. The structure in which the lead is pulled out from the center of the winding is close to the wall of the tank 1 because the high potential portion of the high voltage winding 12 is located at the outermost side. Therefore, the fourth
The insulation distance 21 to the tank shown in the figure had to be increased. The structure that pulls out the lead from the end of the winding has
There are two methods. That is, when there is a high potential portion on the outermost side of the winding, the lead is pulled out from the outermost end. If there is a high potential part on the innermost side, pull out the lead from the innermost end of the winding. This is indicated by a dotted line and a dashed-dotted line in the figure, respectively. In both of these two ways, the yoke insulation distance is 20
acts to make it longer. This causes an increase in magnetic loss due to leakage magnetic flux.

As described above, the conventional high-voltage lead extraction structure mainly causes an increase in the insulation distance, and therefore, structural improvements have been desired.

[Purpose of the invention]

The present invention has been made in view of the problems of the prior art described above, and aims to provide a foil-wound transformer that has high dielectric strength, is compact, and lightweight by improving the lead exit portion.

[Summary of the invention]

In order to achieve the above-mentioned objects, the present invention includes a winding in which a high voltage winding and a low voltage winding are concentrically wound by overlapping and winding a metal sheet and an insulating sheet around an iron core together with an insulating medium. In a foil-wound transformer enclosed in a grounded tank, the potential of the high-voltage winding placed inside the low-voltage winding is made higher toward the outside, and the low-voltage winding wound outside the high-voltage winding is divided into upper and lower halves. , the high voltage lead is drawn out from the highest potential part on the outside of the high voltage winding through the center.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIG. 1 below. The figure shows a cross section of a foil-wound transformer. There is a high-voltage winding 12 wound around the iron core 2 from the outside, and on its outer periphery there are low-voltage windings 5 and 11 that are divided into upper and lower halves.
A high voltage lead wire 10 is drawn out from the outermost side of the high voltage winding 12 wound inwardly through the center of the winding 12. The high voltage lead wire 10 is coupled to an insulating spacer 6 provided on the tank 1 wall. The insulating spacer 6 acts as a guide between the transformer and the high-voltage equipment side conduit 7 and as a support for the high-voltage conductor 9. The high voltage lead wire 10 exits through the insulating spacer 6 and connects to the high voltage conductor 9.
and is connected to high-pressure equipment through a conduit 7. The high-voltage winding 12 shown in the figure is installed so that the potential becomes higher toward the outer side, that is, toward the lower-voltage winding. The low voltage windings 5 and 11, which are divided into upper and lower halves, are connected in parallel.

Further, the potential of the low voltage windings 5 and 11 is lower as the inner side increases, that is,
The high voltage winding 12 side is installed so that the potential becomes higher. In such a configuration, the distance to the tank is 15. Distance to yoke 14
can be significantly reduced.

An example is shown in FIG. For example, if the outermost side of the low-voltage winding 5.degree. 11 is grounded, the distance 15 to the tank is hardly needed for insulation. Only the minimum distance necessary for cooling and assembly is required, which is significantly smaller than conventional methods.

In addition, there is no need to draw out the high voltage lead 10 from the end of the high voltage coil 12, and therefore an insulation distance that takes into consideration the protrusion of the lead becomes unnecessary. Therefore, the insulation distance 14 in this portion can be reduced. Thereby, magnetic loss can be significantly reduced. Note that the magnetic loss is greatly influenced by the distance of this part.

As a result of the above, the insulation dimensions around the low-voltage winding and high-voltage winding can be significantly reduced, making it possible to reduce the size of the foil-wound transformer, thereby reducing its weight and magnetic loss. Since they do not face each other, insulation can be stabilized.

Further, in the present invention, the divided low-voltage windings do not have to have unequal lengths, and the shape of the insulating spacer does not matter whether it is a cone shape or a disk shape.

Further, although the insulating medium of the transformer is an insulating gas, the present invention can also be applied to a foil-wound transformer using an insulating oil as an insulating medium. in this case,
For example, the structure is shown in FIG.

That is, a bushing 18 is used instead of an insulating spacer, and the high voltage lead 10 is connected to the bushing 18 through a bushing pocket 19 and is drawn out. The insulating medium 16 of this transformer and the insulating medium 17 of the bushing pocket 19 are insulating oil.

In this example, as in this example, low voltage windings 5, 11 and tank 1 are used.
The insulation distance 15 between the walls can be significantly reduced.

〔Effect of the invention〕

As explained above, according to the present invention, by improving the lead extraction structure of a transformer, high power consumption can be achieved.

The insulation dimensions around the low-voltage winding can be significantly reduced, thereby making the foil-wound transformer smaller and lighter, stabilizing the insulation, and reducing magnetic loss.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing an embodiment of the present invention.
FIG. 3 is a cross-sectional view showing the effects of the present invention, FIG. 3 is a cross-sectional view showing a modification of the present invention, and FIG. 4 is a cross-sectional view showing a conventional embodiment. 1...tank 12...high voltage winding 2...
・Iron core 14... Yoke insulation distance -7 = 3... Insulator 15... Tank insulation distance 4.8... Insulating gas 16.17... Insulating oil 5
．． 11...Low voltage winding 18...Bushing 6.
... Insulation spacer 19 ... Bushing pocket 7 ... Conduit 20 ... Yoke insulation distance 9 ... High voltage conductor 21 ... Tank insulation distance 10 ... High voltage lead 22 ... High voltage lead agent Patent Attorney Nori Ken Yudo Hirofumi Mitsumata Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) A foil made by enclosing a high-voltage winding and a low-voltage winding concentrically wound around an iron core with a metal sheet and an insulating sheet wrapped together in a grounded tank together with an insulating medium. In a winding transformer, the potential of the high-voltage winding placed inside the low-voltage winding is made higher on the outside, and the low-voltage winding wound outside the high-voltage winding is divided into upper and lower halves, and the high-voltage winding outside is passed through the middle. A foil-wound transformer characterized by a high-voltage lead drawn out from the highest potential part. (2) The foil-wound transformer according to claim 1, wherein the low-voltage winding is divided into upper and lower halves, with the upper winding and the lower winding connected in parallel.