JPS5878408A - Transformer - Google Patents

Abstract

PURPOSE:To improve voltage distribution between a clamp ring and yoke and to shorten the edge insulatng length between a clamp ring and yoke by setting the permitting in unit of insulator provided between a clamp ring and yoke of the high voltage windings to become small as the location moves toward the yoke. CONSTITUTION:An edge insulator 6b provided at the position between a clamp ring 5 and yoke 1B of a high voltage winding 3 is formed with at least pair of insulator units 15, 16 and 17, while insulators 15, 16, 17 shows the dielectric coefficient which becomes small as the location moves toward the yoke 1B from the clamp ring 5. Therefore, a voltage distribution between the clamp ring 5 and yoke 1B attracted toward the yoke 1B as compared with the conventional one as indicated by the equal voltage lines indicated by dotted lines of 90, 80, 70, 60 and 50%. Thereby, the edge insulator length L between the clamp ring 5 and yoke 1B can be shortened and accordingly a transformer can be reduced in size.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transformer, and particularly to a transformer having an end insulator between a clamp ring of a high voltage winding and a yoke of an iron core (hereinafter referred to as a yoke). be.

Conventional examples of transformers are shown in FIGS. 1 and 2. As shown in the figure, a transformer is generally formed by concentrically winding at least a low voltage winding 2 and a high voltage winding 3 around a leg IA of an iron core 1. Insulated clamp rings 4.5 are arranged at both ends of the wires 2, 3, respectively.

Between these low and high voltage windings @2.3 and the leg IA of the iron core 1, and between the low and high voltage windings 2.3, there are insulating cylinders 11 and 12.
The clamp ring 5 of the high-voltage winding 3 and the yoke IB are insulated via the end insulator 6a, and between the high-voltage winding 3 and the low-voltage winding 2 and the high-voltage winding 3 Insulating cylinders 12A, 12B, 12C, IIA, 1
1B are arranged respectively. Between the clamp ring 5 of the high voltage winding 3, that is, the clamp ring 5 formed by insulating the conductor 7 with oil-impregnated paper 8, and the yoke IB, there are oil ducts 9A, 9B, 9C, 9D and oil-impregnated paper. Barrier IOA, 10B
, IOC, and 10D are arranged alternately. The transformer thus formed is used in transformer oil 13. However, the clamp ring 5 and the yoke I determine the length of the end insulation between the clamp ring 5 and the yoke IB.
B, the potential distribution between high voltage winding 3 and 100% (
If the potential of the clamp ring 5 is also the same <ioo%], and the potential of the yoke IB is 0%, and the equipotential lines at 90, 80°, 70.60, and 50% are shown as dotted lines, the potential distribution is the same as that of the clamp ring. The electric field in the oil gap between the separation clamp ring 5 and the oil-immersed paper barrier IOA was the largest.

For this reason, it has conventionally been difficult to downsize the transformer by reducing the length of the end insulation. Note that P in FIG. 1 is a portion where the end insulation of the high voltage winding 3 is constructed.

The present invention has been made in view of the above points, and an object thereof is to provide a transformer that can be downsized by reducing the insulation length of the end portions.

That is, in the present invention, the end insulator disposed between the clamp ring and the yoke of the high-voltage winding is formed from at least two insulator units, and the insulator unit is connected to the yoke from the clamp ring side. It is characterized by a dielectric constant that decreases as it goes to the side.

The present invention will be explained below based on the illustrated embodiments. FIG. 3 shows an embodiment of the invention. Note that parts that are the same as those in the conventional model are given the same reference numerals, and therefore their explanations will be omitted. In this embodiment, the end insulator 6b disposed between the clamp ring 5 of the high voltage winding 3 and the yoke IB is formed of at least two insulator units 15° 16 and 17, and the insulator unit 15° 16.17, the dielectric constant ε is made smaller as it goes from the clamp ring 5 side to the yoke IB side. Here, the insulator 14 of the clamp ring 5 is made of epoxy resin filled with filler, and its dielectric constant e1 is set to 5.5. That is, the insulator unit 15 was formed of filled jepoxy resin, the insulator unit 16 was formed of oil-impregnated paper, and the insulator unit 17 was formed of transformer oil. By doing this, the dielectric constant of the filled epoxy resin is 4.4<, and the dielectric constant of the filled epoxy resin is 9.3.5 to 9 by changing the amount of filler such as alumina. Since the dielectric constant of oil-impregnated paper is 3.5 and the dielectric constant of transformer oil is 2.2, the dielectric constant ε2 of the insulator unit 15 is 4.4.
, dielectric constant ε3 of insulator unit 16 is 3.5, insulator unit 1
7 has a dielectric constant ε4 of 2.2, and the end insulator 6b between the ramp ring 5 and the yoke IB has a dielectric constant ε2.
〉ε3〉The closer it is to No. 6 and the yoke IB, the smaller it becomes. Between the permittivity of the insulator 14 of the lamp ring 5 and the permittivity ε of the insulator unit 15, 61 is 5.5 as described above, so ε□ is large 6. 〉ε2.

In this way, the dielectric constant is made smaller as it goes from the clamp ring 5 side to the yoke IB side, so the potential distribution between the clamp ring 5 and the yoke IB is 90. Like the equipotential lines of 80, 70°, 60, and 50%, the lines are relatively evenly distributed between the clamp ring 5 and the yoke IB, and are attracted and distributed toward the yoke IB compared to the conventional example. However, the end insulation length L' between the clamp ring 5 and the yoke IB can be reduced compared to the conventional method.

In addition, in this example, the end insulator 6b is made up of three insulator units 1.
5, 16, and 17, but if the dielectric constant is appropriately selected, the same operation and effect can be obtained even if the insulator is composed of two insulator units.

Another embodiment of the invention is shown in FIG.

In this embodiment, the end insulator 6C is insulator unit 18°19.
17, and insulator units 18 and 19 were formed with an inclination such that the width becomes narrower from the clamp ring 5 toward the yoke IB. By doing so, the bending radius of the clamp ring 5 is increased, and the electric field in the oil at the end of the clamp ring 5 can be alleviated. In addition, the permittivity of insulator unit 18, 19.17 '6s
It goes without saying that ε5°ε4 is smaller as it approaches the yoke IB, g, )g, )g, as in the case described above.

FIG. 5 shows yet another embodiment of the invention.

In this embodiment, the distance between the high voltage winding 3 and the clamp ring 5 is increased. By doing this, the flow of the transformer oil 13 in the high voltage winding 3 is improved, the high voltage winding 3 can be cooled better, and the cooling effect of the high voltage winding Is3 is required to be improved. The above-described end insulation configuration can also be applied to the above-described materials without any problems.

As described above, in the present invention, the dielectric constant of the insulator interposed between the clamp ring of the high-voltage winding and the yoke decreases as it goes toward the yoke. The potential distribution between the steel and the iron is improved, and the end insulation length between the clamp/pull and the yoke can be reduced, making it possible to reduce the end insulation length and downsize. You can get a suitable transformer.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal side view of a conventional transformer, FIG. 2 is a cross-sectional view of the main parts of the conventional transformer, and FIG. 3 is a cross-section of the main parts of the transformer of an embodiment of the present invention. 4 is a cross-sectional view of the main parts of a transformer according to another embodiment of the transformer of the present invention, and FIG. 5 is a cross-sectional view of the main parts of a transformer according to still another embodiment of the transformer according to the present invention. be. 1゛°° core・1A′°° core・1° core 0
Yoke・2...Low voltage winding, 3...High voltage winding, 4.5・
... Clamp ring, 6b, 6C ... End insulator, 1
51...16°17.18.19...Insulator unit. Figure 1 Figure 5

Claims (1)

[Claims] 1. At least low-voltage and high-voltage windings are concentrically wound around the legs of the iron core, and clamp rings coated with insulation are arranged at both ends of each set of windings, so that at least the clamp rings of the high-voltage windings and the iron core In the device in which an end insulator is interposed between the yoke and the yoke, the end insulator disposed between the clamp ring of the high voltage winding and the yoke of the iron core is formed from at least two insulator units. and the insulator unit has a dielectric constant that decreases from the clamp ring side to the yoke side.