JP3387756B2 - Transformers for gas insulated instruments - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a gas insulation instrument transformer.
On the voltage divider.

[0002]

2. Description of the Related Art A transformer for an instrument is constructed by using resin, oil, gas or the like as its insulating medium, but when the used circuit voltage becomes high, gas insulation is generally adopted.
Figure 4 is a plan layout view showing an entire configuration of a variable voltage divider for a conventional gas insulated instrument, FIG. 5 is an external view showing the shape of a voltage transformer device is housed in the outer box (hereinafter simply referred element), FIG. 6 FIG. 6 is an enlarged sectional view taken along line BB of FIG. 5. In the figure, a gas-insulated instrument transformer 1 has an outer box 2 as a strong hermetic container, and shields the high-voltage coil 3 and the low-voltage coil 4 with electric field relaxation functions and shields 5 and 6 for holding the coils themselves. The structure is such that the iron core 7 is assembled, and they are sandwiched by the frame 8 to form the element 1, which is housed and fixed in the outer box 2. The element 1 is a bushing (not shown)
And a low voltage side terminal box (not shown), and is connected to a high voltage side bus bar, a low voltage side instrument, and the like.

[0003]

However, the transformer for gas-insulated instrument is particularly constituted by a thick cylindrical metal container so that the outer box 2 can withstand a high gas pressure, which causes a large cost factor. Each element 1 housed in the outer box 2 is assembled not only with the high-voltage coil 3 but also with the shield 6 attached to the ground potential side such as the low-voltage coil 4 and the iron core 7, and bolted together. As described above, the conventional gas-insulated instrument transformer is required to be further reduced in cost because the material and the number of steps are increased. Further, in recent years, especially due to difficulty in securing an installation space for power receiving and transforming equipment and the like, there is a strong demand for downsizing of the entire device by incorporating elements. Therefore, it is an object of the present invention to provide a gas-insulated instrument transformer that can be reduced in size while reducing the cost of an outer box and the number of steps for assembling an element, thereby further reducing the cost.

[0004]

In order to solve the So the object, according to an aspect of, the invention of claim 1, radially three instrument-varying voltage divider elements in the outer box is a cylindrical vessel which gas is sealed Each element of a gas-insulated instrument transformer arranged in a plane
Radially evenly arranged in three equal parts and one side iron core at the end of the iron core in the center
From the state of forming an equilateral triangle corresponding to the width, in the longitudinal direction of the iron core
3 instruments so that the central axes of the
Inclining the transformer element for the car
Slide the transformer element for the instrument and surround it with a part of the end of the iron core.
So that a regular triangle
Let α ′ be the distance to the center of the box cylinder and the longitudinal dimension l of the iron core.
Then, the radius r ′ of the outer box is reduced to r ′ = 1 / cos θ + α ′ .

The invention according to claim 2 is the gas according to claim 1.
In the transformer for insulation instrument, the transformer element for instrument is,
Low voltage supported coaxially with each other with low voltage coil inside
Coil and high voltage coil, low voltage coil hollow and high voltage
A ring-shaped iron core arranged so as to go around the outside of the coil
And an electric field relaxation shield arranged on the outer periphery of the high-voltage coil
The iron core is pinched from both sides to hold it, and
Curl inward to cover the inner corners of the iron core facing the
And a pair of frames having a front end formed
Characterize.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan layout view showing an embodiment of the invention of claim 1, which will be described in comparison with FIG. 4 showing a conventional example. As shown in FIGS. 1 and 4, the planar shape of the element 1 of this embodiment is a substantially cross shape in which a shield 5 (which surrounds the coil) having a constant width and an iron core 7 intersect. When the respective elements 1 are arranged in a radial uniform manner, the central axis C in the longitudinal direction of the iron core of each element coincides with the radial direction of the outer casing 2 having a cylindrical shape as shown in FIG. An equilateral triangle corresponding to the width of the iron core is formed.

Here, the longitudinal dimension of the iron core 7 constituting the element 1 is 1, the distance from the end of the iron core to the center point of the outer casing cylinder is α,
If the radius of the outer box is r, then r = 1 + α. On the other hand, as shown in FIG. 1, the central axis C in the longitudinal direction of the iron core 7 of each element 1 is uniformly displaced in the same direction as the radial direction of the outer box 12 by an angle θ, and is further slid toward the central direction. In that case, an equilateral triangle surrounded by a part of the end of the iron core 7 is formed, and if the distance from the end of the iron core 7 to the center point of the outer box 2 is α ′ and the radius of the outer box is r ′, r ′ is = L · cos θ + α ′.

The angle θ cannot take a large value due to the longitudinal dimension of the shield (enclosing the high-voltage coil) and the restriction of securing the distance between the elements, but by uniformly shifting the iron core longitudinal direction from the radial direction of the outer casing cylinder, Although slightly, the radius is reduced at the rate of cos θ. Further, when the distance α ′ is compared with the distance α, one side of an equilateral triangle formed by the end of the iron core in the central portion of the outer box 2 becomes smaller, which is shorter than α. Therefore, FIG.
The radius of the outer case 12 in the arrangement of the respective elements 1 according to 1 is smaller than the radius of the conventional outer case 2 of FIG. 4, and as a result, the entire outer case 12 is reduced.

FIG. 2 is a view showing an embodiment of the invention of claim 2, and FIG. 3 is an enlarged sectional view taken along the line AA of FIG. 2, comparing with FIGS. 5 and 6 showing a conventional example. explain. Figure 5,
As shown in FIG. 6, conventionally, a low-voltage shield 6 is provided separately from the frame 8 at the three window portions of the iron core 7 to cover the iron core 7. At that time, a certain space is required due to the installation of the low-voltage shield 6, the distance between the surface of the iron core 7 and the high-voltage shield 5 increases, and the size of the entire element 1 tends to increase. Moreover, the mounting bolts 9 and the like had to use special rounded parts in consideration of the relaxation of the electric field.

As is well known in the electric field relaxation technique, the problem with the counter electrode is only the electrode end or the sharp protrusion, and it is not necessary to treat the flat portion. Therefore, in the embodiment of the present invention, FIG. 2, as shown in FIG. 3, the core young interference protrudes and distal from the flat portion of the surface of the window side distal end of the core 7 of the frame 18 for holding the core 7 and to the cross-sectional curved shape The tip portion 18a is formed so as to cover the edges at the inner ends of the iron core 7 and to relax the electric field concentration along a smooth curve. Since the frame 18 can integrally molded manufactured by the press mold, it forms a seamless curved shape iron core window side, without the electric field concentration at the connecting portion end surface of the conventional low pressure <br/> shield 6, more stable insulation Has proof stress. Therefore, it is only necessary to secure a distance required for insulation between the high voltage shield and the iron core surface.

Now, comparing this embodiment with the conventional example of FIG. 6, the T dimension required between the low-voltage shield 6 and the inner side surface of the iron core 7 is no longer necessary, and the present invention is accordingly reduced. In the embodiment described above, the size of the entire element 1 was reduced, and miniaturization could be realized. This is the same not only in the height direction but also in the horizontal direction of the iron core window portion, so that it is possible to reduce the entire length, width, and depth elements. Further, as compared with the conventional amount that mounting hardware such as a low pressure shield 6 and the mounting bolt 9 becomes unnecessary, the number of parts and assembly costs are reduced. It is of course possible to apply the element of the second embodiment to the embodiment of the invention of claim 1 shown in FIG. 1, and in that case, the height of the outer box is lowered to further reduce the size. Can be realized.

[0012]

As described above, according to the invention of claim 1, the inner side of the radial center line of each element when the elements are projected in a plane is shifted evenly in one of the rotation directions of the cylindrical container. By arranging the respective elements in this manner, the arrangement dimension of the elements in the radial direction is shortened, and the diameter of the container is reduced accordingly and the size is reduced.

According to the second aspect of the present invention, the electric field mitigation shield is provided on the outer peripheral portion of the high voltage coil, and the pair of frames for holding the iron core by sandwiching the iron core is provided inside the iron core facing the high voltage coil. By forming the inwardly curved tip portion so as to cover the corner portion, the low-voltage side shield becomes unnecessary, and the number of parts and the size can be reduced.

[Brief description of drawings]

FIG. 1 is a plan layout view showing an embodiment of the invention of claim 1;

FIG. 2 is a diagram showing an embodiment of the invention of claim 2;

FIG. 3 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 4 is a plan layout view showing a conventional example.

FIG. 5 is an external view showing a conventional example.

6 is an enlarged cross-sectional view taken along the line BB of FIG.

[Explanation of symbols]

1 element 3 high voltage coil 4 low voltage coil 5 shield 7 iron core 12 outer box 18 frames 18a tip

Claims (2)

(57) [Claims] 1. A cylindrical container containing a gas.Is the outer boxWithin
3 instrument gaugesPressureAre arranged in a radial plane
In gas-insulated transformers, Arrange each element radially equally and equidistantly.
From the state of forming an equilateral triangle corresponding to the width of the side core,
3 pieces so that the central axis of the hand direction is uniformly offset by the angle θ
Inclining the transformer element for the instrument in the direction of the center point of the outer cylinder
Slide the three transformer elements for the instrument to remove the one end of the iron core.
Arrange so that an equilateral triangle surrounded by parts is formed, The distance from the iron core to the center of the outer cylinder is α ', the length of the iron core
Radius r'of the outer box is defined as the dimension l, r '= 1 / cos θ + α' Down to Gas insulation instrument transformer characterized byPressure
vessel. 2. The transformer for gas-insulated instrument according to claim 1.
Oite, the voltage transformer device, a low pressure coil and high voltage coil supported coaxially with each other the low pressure coil inwardly disposed to cycle through the hollow portion and the high pressure coil outside of the low pressure coil A ring-shaped iron core, an electric field relaxation shield arranged on the outer periphery of the high-voltage coil, and a tip that holds the iron core by pinching it from both sides and curves inward to cover the inner corner of the iron core facing the high-voltage coil. varying pressure vessel for a gas insulated instrument characterized by comprising a pair of frame parts was formed, the.