JPH01107429A - High voltage vacuum discharge device - Google Patents

Abstract

PURPOSE:To aim at improvement in yield during conditioning by constituting an insulating vessel in a form with wavy folds with a ceramic so as to become creeping length longer than clearance length between sealing fixtures, besides uniform wall thickness, while making an intermediate shield cylinder so as to be supported on an inner wall of a trough part of the wavy fold. CONSTITUTION:Wall thickness of an insulating vessel 1 is made to be almost uniform over the overall length, while a trough part 1c supporting an intermediate cylinder 3 in wavy folds is set to be equal to each bore diameter of ends 1a, 1b or smaller than it, thereby making the intermediate shield cylinder 3 insertable from either side of these ends 1a, 1b. Consequently, during conditioning, even if vacuum dielectric breakdown occurs between the shield cylinder 3 and two electrodes 5A, 5B, through breakdown is hard to occur in and around support part of the intermediate shield cylinder 3 or in and around both sealing fixtures 6A, 6B. Under such constitution, if a partial discharge occurs, a partial discharge passage comes to head for an external direction from a crest part 1d of the wavy fold, so that it does not reach a trough part 1c of the wavy fold supporting the intermediate shield cylinder 3, thus the yield in a conditioning process is improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to high voltage vacuum discharge devices such as vacuum circuit breakers, vacuum switches, vacuum contactors, vacuum fuses, and vacuum arresters, and particularly relates to high voltage vacuum discharge devices such as vacuum circuit breakers, vacuum switches, vacuum contactors, vacuum fuses, and vacuum arresters. The present invention relates to a high voltage vacuum discharge device including an insulating container for supporting a shield cylinder insulated from two electrodes.

[Conventional technology]

FIG. 6 is a longitudinal sectional view showing a conventional high voltage vacuum discharge device (vacuum switch tube) disclosed in, for example, Japanese Patent Publication No. 59-27050, and in the figure, 1 indicates an insulating container;
It forms part of the vacuum container.

2 indicates a band-shaped protrusion provided on the inner wall of the insulating container 1;
It mechanically supports the metal intermediate shield cylinder 3 and the mounting bracket 4.

5A is a fixed electrode, 5B is a movable electrode, and picture electrode 5A#
5B is supported in an insulated state from the intermediate shield tube 3 by sealing fittings 6A and 6B that are hermetically sealed to the ends 1a and 1b of the insulating container 1, and the end portion is located inside the intermediate shield tube 3. There is.

The insulating container 1 has a function of insulating a high-voltage electrical circuit while the picture electrodes 5A and SB are open, and is generally formed by mixing alumina powder and forming a cylinder using a rubber press.

It is made by cutting molded products, high-temperature firing, etc.

Then, the outer surface is glazed and baked, and the ends 1a and 1b are coated with pi.
The paste is applied and baked using the OM n metallization method.

Sara yc,? +11 plating and its printing are made through various processes.

Next, the operation will be explained.

The vacuum switch tube is completed by assembling the above-mentioned parts by appropriately brazing or welding, heating and evacuating the tube, and vacuum-sealing the tube.

After configuring the vacuum switch tube as described above, a high voltage is applied between the picture electrodes 5A and 5B in a process called conditioning to increase the vacuum breakdown voltage. Rated withstand voltage (e.g. 7.2 K
AC22KV for V.

AC70KV for 36KV, AC2 for 120KV
30 KV), which gives high electrical stress to the insulating container 1.

In this conditioning, especially the intermediate shield tube 3
Since the electric field concentrates on the mounting brackets 4 and the mounting bracket 4, the insulation container 1 is
Penetration failure may occur in the thickness direction. and,
When this penetration failure occurs, the product becomes defective at that stage and cannot be recycled.

Therefore, in order to improve the yield in the conditioning process of vacuum switch tubes having an intermediate shield tube 3, two methods are needed: There is a way to prevent it.

A method for simultaneously carrying out methods (1) and (2) described above is shown in FIG. 7 (Japanese Utility Model Publication No. 58-43152).

Publication of Utility Model Publication No. 58-43153) As shown in FIG. Provide intermediate shield cylinders 9AI and 9B (Fig. 7(b)).
There is a way.

Note that the intermediate shield cylinder 3 corresponds to a first intermediate shield cylinder.

However, with this method, the insulating containers 1 are stacked in multiple stages, and the total length of the vacuum switch tube becomes too long, making it difficult to handle.
Since the structure is complicated, the number of steps required to assemble the vacuum switch tube increases, and each intermediate shield tube 3゜7A, 7B#8A and 8
In order to support B, the inner surface is increased, and another insulating cylinder is provided inside the insulating container 1, so there is a problem that the heating and exhausting process becomes complicated.

Also, each intermediate shield cylinder 3 = 7 A, 7 B a
Since it is necessary to perform conditioning by applying a voltage to B and 8B, there are problems in that conditioning becomes complicated.

Therefore, with this method, it is no longer possible to manufacture the vacuum switch tube economically (at low cost).

In addition, with recent developments, electrode materials with extremely high withstand voltages have appeared, and vacuum switch tubes are becoming increasingly smaller. Considering this from this perspective, conditioner damping of both electric FF15A and FF5B is no longer a problem. As a result, vacuum dielectric breakdown occurs preferentially between the intermediate shield cylinder 3 and the picture electrodes 5A and 5B.

Therefore, even if vacuum dielectric breakdown occurs between the metal between the intermediate shield tube 3 and the picture electrodes 5A and 5B during the conditioning process, penetrating breakdown will occur in the container wall.Therefore, there is a strong demand for the development of a structure for the insulating container 1. There is.

[Problem that the invention seeks to solve]

Since the conventional high-voltage vacuum discharge device is constructed as described above, there is a problem in that the wall of the insulating container 1 is susceptible to penetrating breakdown.

In other words, since the conventional insulating container 1 is made using a dry rubber press method, the fluidity of the alumina powder is poor due to the frictional force of the alumina powder during molding, and the thick band-shaped protruding portion 2 is not sufficiently pressurized. Since it is not added, pinholes are likely to occur.

Therefore, vacuum dielectric breakdown during conditioning will cause the intermediate shield cylinder 3. When the potential of the mounting bracket 4 suddenly changes, abnormal electric field concentration occurs in the pinhole of the band-shaped protrusion 2,
This caused the insulating container 1 to undergo through-breakage.

In addition, the sealed portions of the sealing fittings 6A and 6B are originally areas where electric fields tend to concentrate, and have a high potential gradient toward the inner and outer surfaces of the insulating container 1, so as shown in FIG. As shown, each intermediate shield cylinder 3°7A, 7B, 9A and 8B
Even if this is provided, the effect of alleviating the electric field on the outer surface of the insulating container 1 cannot be said to be sufficient.

Therefore, in order to prevent through-breakage, it is necessary to attach electric field relaxation rings (not shown) to the outer surfaces of the ends 1a and 1b and perform conditioning, which poses problems such as complicated work.

This invention was made to solve the above-mentioned problems. Even if vacuum insulation breakdown occurs between the intermediate shield tube and both electrodes during conditioning, the insulation in the vicinity of the intermediate shield It is an object of the present invention to provide a high-voltage vacuum discharge device in which the container does not undergo through-breakage, and the yield in the conditioning process is improved by suppressing partial discharge toward the outer surface at the end of the insulating container.

[Means for solving problems]

The high voltage vacuum discharge device according to the present invention has a uniform wall thickness,
The insulating container is made of ceramic and has corrugated corrugations so that the creepage length is longer than the gap length between the sealing fittings, and the intermediate shield cylinder is supported by the inner wall of the valley of the corrugated corrugations. be.

[For production]

In the high voltage vacuum discharge device of the present invention, the insulating container is made of ceramic and has a uniform wall thickness and a waveform corrugation so that the creepage length is longer than the gap length between the sealing fittings. Partial discharges that occur from the top to the outer creeping surface are suppressed, and even if a partial discharge occurs, the partial discharge path will be directed outward from the peaks of the corrugated corrugations, and the corrugated corrugations that support the intermediate shield cylinder will be It will no longer reach the valley of the area.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 indicates an insulating container made of alumina ceramic, which has been sintered at approximately 1650°C after forming a slurry of alumina powder, casting, and drying. The valley IC that supports the intermediate shield tube 3 of the folds)'! End portion 1a.

The inner diameter of 1b is the same or smaller, and the end portion 1a+1b
The intermediate shield cylinder 3 can be inserted from either side. The other valley portions are manufactured to have the same inner diameter as the end portion 1 a +1 b.

Reference numeral 1d indicates a peak portion of the waveform folds, and the diameter is larger than the outer diameter of the end portions 1a and 1b.

1e indicates the depth of the corrugated folds, L indicates the gap length between the sealing fittings 6A and 6B, and 2 indicates the creeping length of the insulating container 1.

Note that the intermediate shield tube 3 is mechanically supported by the valley portion 1C by the action of the mounting bracket 40.

FIG. 2 is a partially enlarged cross-sectional view showing a part of FIG. The angle is 120 degrees.

In the embodiments shown in FIGS. 1 and 2, the average wall thickness of the insulating container 1 is 4.5 mm, and the depth 1e of the valley 1c relative to the peak 1d on the outer diameter of the insulating container 1 is 11 mm to 19 m.
m, and the ratio of creepage length 1 to gap length is 1.3.

Next, the operation will be explained.

After creating a vacuum switch tube for 7.2 KV as described above and evacuating the tube, conditioning was performed by applying AC 30 KV.
There were no cases of penetrating failure.

In this invention, during conditioning, even if vacuum dielectric breakdown occurs between the intermediate shield cylinder 3 and both electrodes 5A*5n, the instrument wall will not be damaged near the support part of the intermediate shield cylinder 3 or near the sealing fittings 6A16B. It has the characteristic that penetrating failure is difficult to occur, and the mechanism is thought to be as follows.

1st K. Molding is performed not by dry molding using a rubber press, but by casting using slurry of alumina powder, so the frictional force between the powders is small and the fluidity of the powder is increased.

Therefore, the insulating container 1 with a corrugated flap can be easily formed, and the material of the container wall is made uniform, and the wall thickness is also made uniform.

In addition, as a result of comparing and examining the material properties of the support part of the intermediate shield cylinder 3 for fired products, such as density, transverse rupture strength, and degree of remaining pinholes, we found that cast products are superior in terms of homogeneity. It turned out that.

Second, since the shape of the insulating container 1 is corrugated,
Since the creepage length is 30% longer than the conventional one, surface leakage current from the sealed end is suppressed, and the potential distribution of the insulating container 1 is averaged.

Further, since the outer diameter of the ridge portion 1d of the corrugated folds is larger than the outer diameter of the end portions 1a and 1b, a shielding effect is produced, and partial discharge generated from the sealed portion to the outer surface is prevented.

3rd K, even if a partial discharge occurs from the ends 1a and 1b toward the outer surface, the discharge path of the partial discharge will not go from the peak 1d toward the inner diameter side, but will be parallel to the axis of the insulating container 1. Since the partial discharge has the property of traveling straight in the direction, the discharge path of the partial discharge does not reach the valley portion 1C that supports the intermediate shield cylinder 3.

Therefore, vacuum dielectric breakdown occurs between the intermediate shield cylinder 3 and both electrodes 5A, 5B, and at the same time, the end portion la.

Even if a partial discharge occurs from 1b, penetration damage to the vessel wall near the support portion of the intermediate shield cylinder 3 can be prevented.

Note that although the case where the angle θ is 120 degrees has been explained, if the angle θ is 120 degrees,
may be 90 degrees.

Further, the inner diameter of the valley portion 1C may be configured to be smaller than the inner diameter of the end portions 1a+1b.

FIG. 3 is a longitudinal sectional view showing a high voltage vacuum discharge device according to another embodiment of the present invention, in which the angle θ is 90 degrees.

When configured as shown in Fig. 3, the ratio of the creepage length to the gap length is 1.4, and the effect of suppressing surface current from the sealing fittings 6A and 6B and partial discharge toward the outer surface is improved. As a result, the effect of preventing penetration breakdown of the insulating container 10 is increased.

FIG. 4 is a longitudinal sectional view showing a high voltage vacuum discharge device according to still another embodiment of the present invention, which is applied to a vacuum switch tube having a rated voltage of 84 KV and having a plurality of intermediate shield tubes.

In FIG. 4, 7 At 7 B indicates a pair of second intermediate shield cylinders made of metal, and both 1! Both electrodes 5A are arranged coaxially on the outer periphery of the pole 5At 5B.

It is supported in the valley 1C of the insulating container 1 with a gap length narrower than the gap length between the insulating containers 1 and 5B.

The second intermediate shield tubes 7A and 7B can be attached as shown in the figure by inserting them into the insulating container 1 by using an appropriate method, for example, made of a shape memory alloy, and then heating them.

FIG. 5 is a longitudinal sectional view showing a high voltage vacuum number 11i device according to still another embodiment of the present invention, with a rated voltage of 120K.
This is applied to V vacuum switch tubes.

In FIG. 5, 8A and 8B indicate a pair of third intermediate shield tubes made of metal, and second intermediate shield tubes 7^ and 7B
It is disposed coaxially on the outer periphery of the insulating container 1, and is supported in the trough 1C of the insulating container 1 with a gap length narrower than the gap length between the second intermediate shield tubes 7A and 7B.

In addition, the second. Third intermediate shield cylinders 7A, 7B.

8A and 8B may be constructed of, for example, a shape memory alloy, as explained in FIG. 4, and may be attached as shown.

In the embodiment shown in FIG. 5, the conduit switching voltage between the electrodes 5A and 5B requires AC 350 KV or more, and as the condigi cutting progresses, the second voltage increases. The third intermediate shield cylinders 7h, 7B, 8A, and 8B also gradually became vacuum dielectric breakdown, and finally reached a withstand voltage of AC350 KV or more. During this period, no through-breakage occurred in the insulating container 1 whose wall thickness was substantially uniform.

5K as in the embodiment shown in FIGS. 1 to 5, the valley 1 of the insulating container 1
C indicates each intermediate shield cylinder 317A, 7B.

Supporting 8A and 8B does not increase the inner surface, so the evacuation process can be simplified.

In addition, by applying voltage to the picture electrodes 5A and 5B and performing conditioning, each intermediate shield cylinder 3.7AI7
Since conditioning of B, 8A, and 8B can be performed simultaneously, conditioning can also be simplified.

Although the vacuum switch tube has been described in the above embodiments, other high voltage vacuum discharge devices having an intermediate shield tube inside an insulating container, such as a vacuum HEAZ device, may also be used.

It can also be applied to vacuum lightning arresters, vacuum triggertrons, etc., and the same effect can be obtained.

Although alumina ceramic has been described as the ceramic, other ceramics may be used as long as the sealing fittings 6A+6B can be sealed to the ends.

Further, although the explanation has been made in the case where the fixed and movable electrodes 5A and 5B are used as the electrodes, the picture electrode may be a fixed electrode.

〔Effect of the invention〕

As described above, according to the present invention, the insulating container is made of ceramic and has a uniform wall thickness and has corrugated corrugations so that the creepage length is longer than the gap length between the sealing fittings. Since the structure is such that the intermediate shield cylinder is supported by the inner wall of the valley, the yield during conditioning is improved and the cost is reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a high voltage vacuum discharge device according to an embodiment of the present invention, FIG. 2 is a partially enlarged sectional view showing a part of FIG. 1, FIGS. FIG. 5 is a longitudinal sectional view showing a high voltage vacuum discharge device according to another embodiment of the present invention, FIG. 6 is a longitudinal sectional view showing a conventional high voltage vacuum discharge device, and FIGS. 7(a) and (b). FIG. 2 is a longitudinal sectional view showing another conventional high voltage vacuum discharge device. In the figure, 1 is the insulating container, 1a and Ib are the ends of the insulating container 1, 1C is the valley of the corrugated folds, 1d is the peak of the corrugated folds,
3 is the intermediate shield cylinder, 4 is the mounting bracket, 5A is the fixed electrode,
5B is a movable electrode, 6A, 6B are sealing fittings, 7A# 7B
is the second intermediate shield cylinder, 8A and 8n are the third intermediate shield cylinders, L is the gap length between the sealing fittings 6A and 6B, and J is the creepage length. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Patent Applicant Mitsubishi Electric Co., Ltd. Agent Patent Attorney 1) Hiroshi Sawa (2 others) Figure 2 5B Amendment to the procedure (voluntary) 6 left 4/12 Showa Month Day

Claims (4)

[Claims] (1) An intermediate shield cylinder supported within an insulating container and a sealing fitting sealed to an end of the insulating container are supported in a state insulated from the intermediate shield cylinder, and the end is connected to the intermediate shield cylinder. In a high voltage vacuum discharge device equipped with two electrodes located in a shield cylinder, the insulation has a uniform wall thickness and a waveform corrugated shape such that the creepage length is longer than the gap length between the sealing fittings. A high voltage vacuum discharge device characterized in that the container is made of ceramic, and the intermediate shield tube is supported by the inner wall of the valley of the corrugated folds. (2) The high voltage vacuum discharge device according to claim 1, wherein the minimum inner diameter of the trough of the corrugated folds supporting the intermediate shield cylinder is smaller than the inner diameter of the end of the insulating container. (3) The high voltage vacuum discharge device according to claim 1, wherein the outer diameter of the crest of the corrugated folds is larger than the outer diameter of the end of the insulating container. (4) The high voltage vacuum discharge device according to claim 1, wherein a plurality of intermediate shield cylinders are provided.