JPS6324517A - Vacuum interrupter - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a vacuum interrupter, and particularly to a vacuum interrupter with excellent withstand voltage characteristics.

B1 Summary of the Invention The present invention maintains a constant relationship between the internal and external insulation dimensions of the insulator forming the vacuum vessel of a vacuum interrupter, that is, the vacuum gap dimension between the internal shield along the insulator and the external creepage dimension of the insulator. 1.By setting the midpoint of the vacuum gap and the midpoint of the external creeping dimension of the insulator to be located on approximately the same radial direction line, it is possible to obtain withstand voltage characteristics commensurate with the external creeping dimension. This is an attempt to downsize the vacuum interrupter.

C1 Prior Art Since the vacuum gap inside the vacuum interrupter has a large dielectric strength, even a small gap can withstand high voltage.

However, since the dielectric strength on the external surface side is small, one way to increase the voltage in vacuum interrupters is to generally lengthen the external creepage dimension of the vacuum vessel, which is the part with weak dielectric strength. There is. As a means of increasing the external creepage dimension, if the diameter of the vacuum container is the same, the total length of the vacuum container can be increased, or if the total length of the vacuum container is not changed, the diameter of the vacuum container can be increased and the external creepage dimension can be increased. It has an insulating molded body.

D1 Problem to be solved by the invention In order to improve the external dielectric strength of the vacuum interrupter,
If the dimension of the insulating part that forms the vacuum container is made longer C or the radial dimension is increased, there is a problem that the vacuum interrupter becomes larger.

Furthermore, it has been found that even with such means, the withstand voltage characteristics do not improve much in proportion to the external creepage dimensions.

In other words, Fig. 5 shows the relationship between the external creepage dimension and the withstand voltage value, and compared to the calculated value, the withstand voltage characteristics of an actual vacuum interrupter are even when the external creepage dimension Q becomes large. It turns out that it doesn't improve much.

Means for Solving Problem E1 Therefore, the present inventor focused on the vacuum gap between opposing shields existing inside the insulating part of the vacuum container and the electric field strength outside the insulating part corresponding to this gap.

In other words, if the vacuum gap is small, the outer surface of the insulating part is poorly utilized, and the electric field strength becomes locally high, which is considered to be a cause of flashover on the outer surface.

On the other hand, if the vacuum gap is large, the utilization of the outer surface of the insulating cylinder improves, but electric field concentration occurs at the sealing fittings 4 and 5 provided at both ends of the insulating cylinder 1, which is considered to be a cause of flashover.

For this reason, we attempted to improve the withstand voltage characteristics by changing the relationship between the gap dimension and the external creepage dimension.

(Experiment-1) The experiment was carried out in the manner shown in FIG. Figure 3 shows an experimental model simulating a vacuum interrupter, where l is an insulating cylinder made of alumina ceramics, 2.3 is 5US30
This is an end plate made of 4L. 4 and 5 are sealing fittings made of copper (Cu), 6.7 are bellows made of 5US304L,
8 and 9 are movable electrode rods made of copper (Cu). End plates 2 and 3 are airtightly attached to the insulating cylinder l using sealing fittings 4 and 5. The end plate 2 and the movable electrode rod 8 are airtightly attached via the bellows 6, and the end plate 3 and the movable electrode rod 9 are airtightly connected via the bellows 7. Electrodes 10 and 11 each made of 5US304 are attached to the inner end of the movable electrode rod 8.9, and are formed so that the vacuum gap dimension g can be varied. Note that the electrode 10
．． The outer diameter of 11 is 10 mm, and the inner diameter of insulating tube l is 80ttt.
It is m.

In the model shown in Figure 3, the pressure inside the vacuum vessel is 13.33
vPa (10-'Torr) or less, and the external creepage dimension ρ of the insulating cylinder l is 9Qxn and 150. Experiments were conducted with two types of yz.

FIG. 6 shows the experimental results when the external creepage dimension of the insulating cylinder l is ρ=90ux. Impulse voltage (IX 40 μs) was applied by changing the dimensions and the voltage value, and the voltage value at the time of flashing (average value of 10 flashings) was investigated.

In addition, the vacuum gap dimension g and the external creepage dimension σ of the insulating cylinder l
The positional relationship between g/2 (center of g) and f/2 (I
The experiment was conducted so that the two centers of the two sides substantially coincided on the same radial line.

As is clear from the experimental results shown in Figure 6, good results were obtained with g-20 to 40 mm for Q90xx, and g-1
It was found that 5 to 4811 baths were sufficiently usable.

That is, it has been found that g/12'' may be set to 0.16 to 0.53, preferably 022 to 0.44.

In addition, when g/ρ is 0.16 or less, it is considered that the electric field on only a part of the external creeping surface of the insulating tube I becomes locally strong, which triggers the flashover.

When g/Q was 0.53 or more, flash shorting occurred due to electric field concentration occurring in the sealed metal section.

Also, the same result g#! is obtained when the external creepage dimension σ of the insulating tube l is 150 mx! A relationship of =O, ra~0.53 was obtained.

(Experiment-2) Furthermore, the model shown in FIG. 4 is obtained by applying a resin mold 12 to the outside of the model shown in FIG. 3. The external creeping dimension of the insulating cylinder l is ρ = 90 (xi), the length of the molded body 12 (external creeping dimension) L = 140 (im), the outside diameter of the molded body 12 applied to the vacuum container is 120 (xi),
As the molding resin, X-467 (made by Union Kasei) was used.
(Urethane mold) was used.

The above experiment-1 was carried out with the g/2 point and L/2 point matched.
A similar experiment was conducted.

As a result, even when a molded body is provided externally,
The relationship between the vacuum gap dimension g and the external creepage dimension of the mold body is the same as in the case of the previous experiment-■, that is, g
/L=0.16~o53 (preferably 0.22~0
．． 44), it was found that good results could be obtained.

Therefore, from the results of Experiments 1 and 2, the relationship between the vacuum gap dimension g formed in the vicinity of the inner wall surface of the vacuum vessel and the external creepage dimension Q (or L) can be determined as g#! (or g
/L) is 0.16 to 0.53 (preferably 0.22 to
0.44), it was found that a vacuum interrupter with withstand voltage characteristics commensurate with the external creepage dimension 12 (or L) could be constructed.

The present invention has been made based on the above-mentioned results, and includes a fixed electrode and a movable electrode in a vacuum container including an insulating section, which are opposed to each other at different potentials through a vacuum gap within the vacuum container and along the insulating section. In a vacuum interrupter equipped with a shield, the vacuum gap dimension of the shield is 0.16 to 053 (preferably 0.2
2 to 0.44), and the midpoint of the vacuum gap and the midpoint of the external insulation creepage distance are set so that they are located on substantially the same radial line.

F6 Effect Therefore, according to the present invention, by the above-mentioned means, a small-sized vacuum interrupter having voltage resistance characteristics commensurate with the external creepage dimension can be obtained.

G. EXAMPLES The present invention will be specifically explained below with reference to first and second examples shown in FIGS. 1 and 2.

The vacuum interrupter of the first embodiment shown in FIG.
A metal end plate 3 made of 5US304L is airtightly provided via a sealing fitting 5 made of . The other end of the insulating tube 1 is airtightly connected to the open end of a bottomed metal tube 13 made of 5US304L via a sealing fitting 4 made of Cu.

A fixed electrode rod 8 is hermetically inserted through the bottom of the metal tube 13, and a fixed electrode 14 is provided at the inner end of the fixed electrode rod 8. The metal end plate 3 has a movable electrode rod 9 whose end is connected to the metal cylinder 1.
A movable electrode 15 is attached to the inner end of the movable electrode rod 9 . The bottom of the bellows 6 is airtightly attached to the movable electrode 9.
The open end of the metal end plate 3 is airtightly attached to the inner surface of the metal end plate 3 on the vacuum side. Therefore, insulating cylinder 1. Metal end plate 3. A vacuum container 20 is formed by the sealing fitting 4.5 and the bellows 6.

Inside the vacuum container 20, a shield 16 is provided to prevent metal vapor from adhering to the arc generated when the current is cut off.
is positioned inside the insulating cylinder I and fixed to the sealing fitting 4.

Further, the movable electrode rod 9 is provided with a bellows shield 17 for protecting the bellows 6.

Based on the results of Experiment 1 mentioned above, the vacuum gap dimension g between the shield 16 and the bellows shield 17 in the vacuum container 20 when the electrodes are opened, and the external creepage of the insulating cylinder 1 forming the vacuum container 20 are determined. The relationship with dimension Q is expressed as g/σ
It is set to -0,293.

In addition, the g/2 point, which is the midpoint position of the vacuum gap between the shield 16 and the bellows shield 17, and the 172nd point, which is the midpoint of the external creepage dimension ρ of the insulating cylinder 1, are made to substantially coincide with each other. The entire length of the external creeping dimension a of the tube 1 can be effectively utilized.

Note that electric field concentration at the joints of the sealing fittings 4.5 at both ends of the insulating cylinder 1 is prevented by the presence of the shield 16 and the bellows shield 17.

FIG. 2 shows a second embodiment of the present invention, and the same or equivalent parts as those in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted.

In this embodiment, in order to increase the external insulation dimensions of the vacuum container 20, a molded body 12 made of epoxy resin such as urethane is provided on the outer peripheral surface of the vacuum container 20.

In the vacuum interrupter shown in FIG. 2, the relationship between the vacuum gap dimension g between the shield 16 and the bellows shield 17 at the time of opening and the external creepage dimension of the vacuum container 20 formed by the molded body 12 is expressed as g/L=0. 31 and g
The /2 point and the L/2 point were set to be on substantially the same radial line of the vacuum vessel 20.

According to the vacuum interrupter shown in FIG. 2, it is possible to obtain a dielectric strength commensurate with the external creeping dimension of the molded body 12, so that the axial dimension of the insulating cylinder 1 forming the vacuum container 20 is not increased. A vacuum interrupter that can be used at a higher voltage than that shown in Figure 1 can be formed.

Although the above embodiments have been explained in the case where one of the shields of a pair of shields forming a vacuum gap is movable, the present invention is not limited to this, and both shields are statically deaf. It can be implemented in the same way on the opposite side.

Furthermore, the same method can be implemented even if one of the shields has an intermediate potential.

In short, it can be implemented in the same manner as long as the shields are located within a vacuum container, along an insulator, and facing each other at different potentials via a vacuum gap.

H1 Effects of the Invention The present invention provides a vacuum gap dimension g between shields facing each other at different potentials provided within a vacuum vessel and along an insulating part forming the vacuum vessel, and an external creepage dimension Q of the insulating part, (or L
) is set to g/ρ (or g/L) = O, 16 to 0.53, and since the g/2 point and the Q/2 (or L/2) point are approximately matched, the external creepage A vacuum interrupter having voltage resistance characteristics commensurate with the dimension Q (or L) can be formed.

Therefore, it is possible to obtain a small-sized vacuum interrupter with excellent withstand voltage characteristics without increasing the size of the vacuum container, especially the insulating portion, and this also contributes to downsizing of the vacuum interrupter.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a vacuum interrupter according to a first embodiment of the present invention, FIG. 2 is a partially cutaway front view of a vacuum interrupter according to a second embodiment of the present invention, and FIGS. 3 and 4 are respectively A partially cutaway front view of a simulated model of a vacuum interrupter used in experiments leading to the present invention, Figure 5 is a diagram of the withstand voltage characteristics of the vacuum interrupter against external insulation creepage distance, and Figure 6 is a vacuum obtained by the model in Figure 3. It is a withstand voltage characteristic diagram with respect to gap dimension. DESCRIPTION OF SYMBOLS 1... Insulating tube, 3... Metal end plate, 4.5... Sealing fitting, 12... Mold body, 13... Metal tube, 14
... Fixed electrode, 15... Movable electrode, 16... Shield, 17... Bellows shield, g... Vacuum gap dimension, C... External creeping dimension of insulating tube, L... Mold body external creepage dimensions. (-$, actually sH's 2nd history 15 夛j) (NeJ Vinegar's 1st 1------Ichishoshatsutsu 3------4 Drama Hunting 4.5--Ichifu 4tP 12--------Mold loincloth 13------Ichie Enenzutsu 14------Ichikyui Arrival 15--------Ichitemu@Ko 16--------Shield 17 --------- Hole Rose Shield 9 ------ One beggar cut off Gunseok-myeon Ihong 3rd
Figure (1st leg model) (box moxibustion test model)

Claims (3)

[Claims] (1) A vacuum vessel is formed by an insulating part and a metal part connected to the insulating part, a fixed electrode and a movable electrode are provided in the vacuum vessel, and a vacuum gap is created within the vacuum vessel and along the insulating part. In a vacuum interrupter in which shields are disposed facing each other at different potentials through the vacuum interrupter, the vacuum gap dimension between the facing shields is 0.1 with respect to the external creepage dimension of the insulating part.
A vacuum interrupter characterized in that the ratio is set at a ratio of 6 to 0.53, and the midpoint of the vacuum gap and the midpoint of the external creeping dimension of the insulating part are located on substantially the same radial line. . (2) The vacuum interrupter according to claim 1, wherein the insulating section is an insulating cylinder. (3) The vacuum interrupter according to claim 1, wherein the external creeping dimension of the insulating section is the external creeping dimension of a molded body provided on the outer surface of the vacuum container.