JPH0898341A - Switch gear - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a switchgear that has an improved insulating structure and can be made small in overall shape. [Construction] In the circuit breaker 3 housed in a box, a vacuum interrupter 3a is mounted in an insulating cylinder 17, and an insulating layer 23 is formed from an acute angle portion of the outermost diameter portion of the flange to the creeping surface of the insulating container. Further, a silicone gel 22 is filled between the insulating cylinder 17 and the vacuum interrupter 3a.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a switchgear.

[0002]

2. Description of the Related Art FIG. 9 shows an example of the structure of a switchgear.
In the gas-insulated switchgear shown in Fig. 1, the inside of the box 1 whose outer periphery is airtightly surrounded by a mild steel plate is formed by a partition wall 2 vertically provided near the front surface on the left side in the drawing, and a breaker chamber 1a at the front and a busbar at the rear. It is partitioned into chambers 1b, and sulfur hexafluoride gas (hereinafter abbreviated as insulating gas) is enclosed in the chambers 1a and 1b.

Of these, a circuit breaker 3 having a vacuum interrupter 3a sealed therein is housed inside the circuit breaker chamber 1a, and a partition wall 2
The insulating bushing 9 attached to the through hole (not shown) and the circuit breaker 3 are connected. This insulating bushing 9
The upper and lower sides have the same structure.

Further, the disconnector 4 is provided on the ceiling of the bus room 1b.
A is attached, one terminal is connected to the upper insulating bushing 9 via the connecting conductor 8, and the other terminal is connected to the busbar 5 fixed to the rear insulator 6 via the connecting conductor 8. The bus bar 5 interconnects the adjacent boards.

On the other hand, a disconnector 4A is provided at the bottom of the bus room 1b.
A cable in which a disconnecting switch 4B having the same shape as the above is attached, one terminal is connected to a lower insulating bushing 9 through a connecting conductor 8 and the other terminal is vertically attached behind the bottom plate through the connecting conductor 8. It is connected to the upper terminal of the head 7. The cable connected to the cable head 7 receives electricity.

FIG. 10 shows a sectional view of the circuit breaker 3 in these configurations. The vacuum interrupter 3a is housed in the insulating cylinder 10, and the upper and lower electrodes 11a and 11b fixed to the insulating cylinder 10 with bolts are fixed. Upper and lower electrodes 11a, 11
The connection conductors 12a and 12b are respectively connected to b,
Connection with other electric devices is performed via the contacts 13a and 13b. Further, a contactor (not shown) is housed in the lower electrode 11b, and is connected to the central conductor 14 of the vertically moving vacuum interrupter 3a. An insulating operating rod 15 is connected to the central conductor 14, and the operating mechanism 16 opens and closes the electrodes in the vacuum interrupter 3a.

Here, an insulating gas is enclosed inside and around the insulating cylinder 10 as disclosed, for example, in Japanese Utility Model Publication No. 1-15071. Due to the shape of the box body 1, the pressure of the insulating gas is not a pressure vessel and is approximately atmospheric pressure near 0.10 MPa at 20 ° C. conversion. For this reason,
The insulation performance is determined by the gas pressure of the insulating gas, and the electric field is relaxed in each part so that the electric field strength is equal to or lower than the allowable electric field strength required by the gas pressure.

[0008]

By the way, the breakdown voltage when the insulating gas is filled in this way can be obtained from the following equation.

[0009]

## EQU00001 ## Breakdown voltage Vd = 89.p.u.d (1 + 0.175 / √p.R) [kV] (1) where p is gas pressure, d is gap length, and u is electric field utilization rate. , R is the harmonic mean of radii of curvature in two directions orthogonal to each other at the point on the electrode where the maximum electric field strength is given.

Therefore, according to the equation (1), it is possible to increase the gas pressure p or increase the gap length d in order to improve the breakdown voltage. However,
When the gas pressure rises, it is necessary to increase the plate thickness of the box body 1 and change the shape to a cylinder or the like to form a pressure container. On the other hand, increasing the gap length is a storage device that uses a large number of electrodes. Therefore, if the gap length is secured corresponding to each, the overall shape becomes large.

It should be noted that it is related to the electric field utilization rate u and the radius of curvature R of the electrode. In order to relax the electric field, the electrode has a large roundness, and accordingly, the electric field utilization rate u approaches 1 and the curvature is increased. Although the radius R becomes large and the breakdown voltage rises, there is a limit to this. That is, when the radius of curvature of the electrode is increased in a limited space, the electric field strength seems to be reduced, but the gap length is shortened, and as a result, the electric field strength is increased and the breakdown voltage is not improved. It will be.

As described above, in order to increase the breakdown voltage, the gas pressure is increased and the box 1 becomes a heavy object, which is not legally regulated as a pressure container. It became large and there was a limit to the reduction. An object of the present invention is to provide a switchgear capable of improving the insulating structure and reducing the overall shape.

[0013]

In order to achieve the above object, the present invention relates to a circuit breaker housed in a switchgear in which a vacuum interrupter is mounted in an insulating cylinder and silicone gel is filled therein, and a flange of the vacuum interrupter is provided. An insulating layer made of epoxy resin or the like is provided on a metal portion having an acute angle such as.

The movable operating rod portion is covered with a flexible material made of silicone rubber on both ends of the operating rod so as to prevent the silicone gel from being filled and allow the operating rod to move movably. .

[0015]

In such a structure, the breakdown voltage of the silicone gel is higher than the breakdown voltage at 0.10 MPa and higher than the insulating oil, and has a high insulating performance by itself. Further, the breakdown voltage of the silicone gel is greatly affected by the electric field strength, and the electric field strength can be suppressed and greatly improved by providing an insulating layer made of epoxy resin or the like on the metal part.

Further, in the movable part, the movable distance becomes several tens of mm in conjunction with the gap length of the electrode of the vacuum interrupter, but the flexible material can absorb this movable distance, and the silicone adhered to the insulating operation rod can be made. Similarly, gel can absorb a large amount of elongation of the material.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A switchgear insulating structure showing an embodiment of the present invention will be described below with reference to the drawings. However,
The same parts as those of the conventional device are designated by the same reference numerals. Figure 1
FIG. 3 is a cross-sectional view of the circuit breaker 3 housed in the switchgear showing an embodiment of the present invention. A vacuum interrupter 3 a is mounted in the insulating cylinder 17 and fixed to the upper electrode 18 and the lower electrode 19. A connection conductor 20a is connected to the upper electrode 18, and these are integrally embedded in an insulating layer 21,
It is fixed to the insulating cylinder 17. Further, the central conductor 14 penetrates through the lower electrode 19 and is fixed to substantially the middle portion of the insulating cylinder 17. An insulating operating rod 15 is connected to the central conductor 14, and an operating mechanism 16 opens and closes an electrode in the vacuum interrupter 3a.

The upper and lower electrodes 18, 19 are connected to other electrical equipment by connecting conductors 20a, 20b and contacts 13a, 13b attached to the tips of the connecting conductors 20a, 20b.

Here, in the insulating cylinder 17, the upper electrode 18
Before being attached, the silicone gel 22 is filled, and an insulating layer 23 made of an insulating material such as epoxy resin is formed on a metal portion such as a flange of the vacuum interrupter 3a. The silicone gel 22 is, for example, Toshiba Silicone XE-14 and has a shear adhesive strength of 0.64 kgf.
There is a physical property value having an elongation of 1100 mm / cm ² according to the test method according to JIS-A5758-2 type, and it hardens and gels at room temperature for more than 10 hours.

FIG. 2 shows the flange 2 of the vacuum interrupter 3a.
4 is a sectional view of a portion where the insulating layer 23 is formed. The insulating layer 23 has an insulating thickness of several mm and is provided up to the flat surface portion 24a of the flange 24 by wrapping it around the creeping surface portion of the insulating layer 25 centering on the acute angle portion of the flange 24. This means that the insulating layer 23 covers a portion having a high electric field strength and a portion having a sufficiently low electric field strength at an acute angle portion. The insulating layer 23 can be formed by dipping an insulating material such as an epoxy resin that is cured at room temperature. A silicone gel 22 is filled around these.

Further, FIG. 3 shows a sectional view of the movable portion. A connecting rod 26 having an upper portion connected to the central conductor 14 and a lower portion connected to the operating mechanism 16 is fixed to the insulating operation rod 15 by a nut 27. The center conductor 14 penetrates the central portion of the concave lower electrode 19 and is electrically connected to the lower electrode 19 by the contact 28. The connecting rod 26 is a concave ground electrode 2 corresponding to the lower electrode 19.
It penetrates through the central part of 9. Further, one of the coating layers 30 made of a flexible material such as silicone rubber is used for the nut 2
7 is clamped and fixed, and the other is sandwiched and fixed inside the concave protruding portion 19 a of the lower electrode 19 and the protruding portion 29 a of the ground electrode 29. Silicone gel 22 is filled in the periphery of these through holes 17 a provided in the side surface of the insulating cylinder 17 as in the upper portion. In addition, at the time of filling, as shown by the solid line in FIG. 3, the insulating operation rod 15 is placed in an open state with its lower position. The closed state is as shown by the dotted line, and the air layer 31 absorbs the movement distance at the time of opening and at the time of closing.

Next, FIG. 5 shows impulse breakdown voltage characteristics when the insulation distance 1 is changed to 20 mm using the electrode arrangement shown in FIG. The solid line (a) is the silicone gel, the dotted line (b) is the silicone oil, and the alternate long and short dash line (c) is the insulating gas characteristic of 0.10 MPa at 20 ° C. conversion.

From FIG. 5, it can be seen that the dielectric strength of silicone gel is higher than the characteristics of silicone oil and insulating gas, and about twice that of insulating gas. Therefore, even in the case of an insulating structure of silicone gel alone, reduction in size can be achieved in inverse proportion to the rate of improvement in dielectric strength. Note that the breakdown of the silicone gel is greatly affected by the electric field strength.

By the way, since silicone gel is soft and has no mechanical strength, it is used in combination with a solid insulator, and an interface is formed between different kinds of insulators. The characteristics of this interface were investigated by the electrode arrangement of the smooth interface of FIG. 6 and the coating interface of FIG. 7. The electrode 33 was placed on the epoxy resin 32 plate, and the breakdown voltage was obtained by filling the silicone gel 34. Reference numeral 35 is an insulating layer of epoxy resin having an insulating thickness of about 1 mm. The distance between the electrodes is 10 mm.

The results are shown in FIG. The solid line (d) is the impulse voltage, the dotted line (e) is the AC voltage, and the alternate long and short dash line (f) is the partial discharge inception voltage. According to FIG. 8, all the voltage characteristics of the coated interface are improved with respect to the smooth interface, and the impulse voltage is about double. This is because the electric field strength is suppressed by the insulating layer 35, and in particular, the electric field strength is suppressed from being increased by the triple jean cushion that occurs at the contact points between the electrode 23 and the epoxy resin 32 and the silicone gel 34.

Therefore, by forming the insulating layer 23 on the acute angle portion of the flange 24 of the vacuum interrupter 3a in which the electric field strength increases, the dielectric strength of the interface can be greatly improved. Therefore, the distance between the poles and the distance to the ground can be reduced.

Further, in the movable part, the insulating operation rod 15
Since the silicone gel 22 is in close contact with the core conductor 14 and the connecting rod 26 has a small diameter, the electric field strength does not increase and high dielectric strength can be maintained. During the movement, the coating layer 30 has flexibility and the silicone gel 22 also has a high elongation, so that it is possible to cope with the movement of ten and several millimeters. The upper and lower electrodes 19 and 29 are concave, and a part of the insulating operation rod 15 and the attachment end of the coating layer 30 are accommodated in the bottom of the electrode, so that the electric field is sufficiently relaxed and partial discharge or the like occurs. There is nothing to do.

As described above, according to this embodiment, with respect to the insulating structure of the circuit breaker which is the storage device of the switch gear, the insulating layer is provided on the metal portion having the acute angle portion such as the flange, and these are mounted on the insulating cylinder. High dielectric strength is achieved by filling with silicone gel and gelling, and at the movable part, a protective film is provided to prevent silicone gel from penetrating into the moving shaft part of the flexible material coating layer. It is possible to obtain a switchgear that is formed to improve the dielectric strength and absorb movement to reduce the overall shape.

On the other hand, in another embodiment, the dielectric constant of silicone gel is about 2.7, while the dielectric constant of the insulating layer coating the electrode is as large as about 5, so that the interface between these insulating layers is large. Then, the electric field strength is disturbed. Therefore, when the insulating material of the insulating layer is made of a low dielectric constant such as polyethylene, the electric field strength at the interface is less disturbed, and the dielectric strength is further improved.

Although the case where the circuit breaker is used to fill the silicone gel has been described, the same effect can be obtained by filling the entire switch gear with the silicone gel. In this case, a high dielectric strength can be obtained by providing a film of an insulating layer on at least an acute angle portion of the main circuit conductor where the electric field strength increases or an exposed metal portion. In addition, such a coating film having a large area can be collectively formed by a fluidized bed method. Also, it can be formed by a heat shrinkable tube except for the connection point.

[0031]

As described above, according to the present invention, in a switchgear partitioned by a partition wall in the box into a circuit breaker chamber for accommodating the circuit breaker and a busbar chamber, the circuit breaker is mounted in an insulating cylinder. Since it has a vacuum interrupter and an insulating layer formed from at least the acute-angled portion of the outermost diameter of the flanges sealed above and below the insulating container of the vacuum interrupter to the creeping surface of the insulating container, the insulating structure can be improved, The shape can be made small.

[Brief description of drawings]

FIG. 1 is a sectional view of a circuit breaker housed in a switchgear showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the upper part of FIG.

FIG. 3 is a bottom enlarged cross-sectional view of FIG.

FIG. 4 is a diagram for explaining insulation characteristics of a switchgear according to an embodiment of the present invention.

FIG. 5 is a diagram for comparatively explaining voltage characteristics of an insulating medium applied to a switchgear according to an embodiment of the present invention and a typical insulating medium.

FIG. 6 is a diagram for explaining insulation characteristics of a switchgear according to an embodiment of the present invention.

FIG. 7 is a diagram for explaining insulation characteristics of the switchgear according to the embodiment of the present invention.

FIG. 8 is a diagram for comparatively explaining breakdown voltage characteristics of an insulating medium applied to a switchgear according to an embodiment of the present invention and a typical insulating medium.

FIG. 9 is a side view showing the configuration of a typical switchgear.

FIG. 10 is a sectional view of the circuit breaker housed in the switchgear of FIG. 9;

[Explanation of symbols]

1 ... Box body, 3 ... Circuit breaker, 10 ... Insulating cylinder 21, 23, 2
5, 35 ... Insulating layer, 22, 34 ... Silicone gel

Claims (5)

[Claims] 1. A switchgear which is partitioned into a circuit breaker chamber and a bus chamber in which a circuit breaker is housed by a partition wall in the box body,
The circuit breaker is a vacuum interrupter mounted in an insulating cylinder, and an insulating layer formed from at least the acute-angled portion of the outermost diameter portion of the flanges of the vacuum interrupter sealed above and below the insulating container to the creeping surface of the insulating container. And a silicone gel filled between the vacuum interrupter and the insulating cylinder. 2. The insulating layer of the circuit breaker is made of an insulating material made of polyethylene resin, and has a low dielectric constant close to that of the silicone gel filled in the insulating cylinder. Switch gear. 3. A switchgear which is partitioned into a circuit breaker chamber and a busbar chamber in which a circuit breaker is housed by a partition wall in the box body,
The circuit breaker includes a vacuum interrupter mounted in an insulating cylinder, an insulating operating rod that allows the electrodes in the vacuum interrupter to come into contact with and separate from each other, and the insulating operating rod is formed with one fixed and the other insulated. A switchgear having an insulating coating layer fixed to an electrode penetrating the operating rod, wherein the insulating operating rod is filled with silicone gel. 4. An operating mechanism for operating the insulating operating rod and a connecting shaft for connecting the insulating operating rod, and a concave shape which is arranged to face the connecting shaft and which penetrates the connecting shaft through a through hole formed in a central portion of the bottom. 5. The switchgear according to claim 4, characterized in that the distance that the insulating operating rod moves is within the range of the concave depression of the electrode. 5. An electric device housed in a box, a solid insulator for supporting and fixing a main circuit conductor of the electric device, and at least an acute angle portion of the main circuit conductor of the electric device to the solid insulator. A switchgear having an insulating coating layer that is filled with silicone gel.