JPH0115071Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a vacuum circuit breaker, and particularly to a structure with improved dielectric strength.

[Technical background of the invention and its problems] In recent years, in order to reduce the size of closed switchboards and make maintenance and inspection easier, closed boxes that house vacuum circuit breakers and other electrical equipment are being filled with gas, such as SF ₆ gas. A gas-insulated closed switchboard filled with an insulating medium was developed.
It is starting to be put into practical use.

The vacuum circuit breaker used in this gas-insulated closed switchboard has a configuration in which an operating mechanism section (not shown) is provided at the bottom, and a interrupting section that is opened and closed by the operating mechanism section is provided at the top.

As shown in FIG. 3, the cutoff section 1 is constructed by fixing an upper electrode 3 to the upper end surface of an insulating cylinder 2 with a screw 4, passing a fixed energizing shaft 6 of a vacuum valve 5 through the upper electrode 3, and tightening a nut. By tightening 7,
It has a structure that supports the vacuum valve 5. A movable energizing shaft (not shown) of the vacuum valve 5 is connected to an operating mechanism (not shown) provided at the bottom to open and close contacts of the vacuum valve 5.

As is clear from the figure, there is no problem with the dielectric strength of the vacuum valve body 5 because the insulating cylinder 2 serves as a partition wall, but since the upper electrode 3 is outside the insulating cylinder 2, it is difficult to maintain the dielectric strength of the closed box on the ground side. The dielectric strength between the door or partition wall (hereinafter referred to as panel wall) 8 becomes a problem.

On the other hand, there is a method of increasing the radius of curvature of the outer peripheral surface of the upper electrode 3 to alleviate the potential gradient.
As shown in FIG. 4, when the radius of curvature is increased and the lower surface of the upper electrode 3 is aligned with the upper end surface of the insulating cylinder 2, and the upper electrode 3 is fixed to the insulating cylinder 2 with the screw 4, the upper electrode 9 is The shape is shown in
The insulation distance between the panel wall 8 and the upper electrode 3 becomes smaller.
In addition, when trying to secure the insulation distance between the panel wall 8 and the upper electrode 3, a contact angle θ is formed between the upper end surface of the insulating cylinder 2 and the outer peripheral surface of the upper electrode 3, and a small gap due to this contact angle θ is formed. To facilitate generation of discharge between the upper electrode 3 and the insulating cylinder 2 in a high electric field. In other words, a small gap due to the contact angle θ becomes a weak point of discharge between the upper electrode 3 and the insulating cylinder 2. This increases the potential gradient in this portion and reduces the dielectric strength.

Therefore, if the radius of curvature of the outer peripheral surface of the upper electrode 3 is increased, it is necessary to increase the insulation distance between the upper electrode 3 and the panel wall ₈ , which increases the size of the entire gas-insulated closed switchboard. Even if gas is filled in, it cannot be reduced in size.

[Purpose of the invention] The present invention was made in view of the above-mentioned circumstances, and its purpose is to provide a vacuum circuit breaker with improved dielectric strength by relaxing the potential gradient of the upper electrode attached to the upper part of the insulating cylinder. shall be.

[Summary of the invention] The invention consists of an operating mechanism section and a cutoff section in which a vacuum valve is housed in an insulating cylinder.
By stacking multiple electrode members with different radii of curvature on the outer circumferential surface and arranging the member with a larger radius of curvature on the upper stage, the radius of curvature of the outer circumferential surface of the upper electrode is substantially increased, and the radius of curvature between the upper electrode and the insulating cylinder is increased. The dielectric strength is improved by preventing the formation of minute gaps between the two, thereby reducing the size of the gas-insulated closed switchboard.

[Embodiment of the invention] Hereinafter, an embodiment of the vacuum circuit breaker of the invention will be described with reference to the drawings. First, the configuration of a gas-insulated closed switchboard will be explained with reference to FIG. In the figure, a closed box 10 is formed airtight and filled with SF ₆ gas, and has a vacuum circuit breaker 11 inside, a disconnect switch 12 connected to an operating mechanism (not shown) via a lever 12a, and an insulating support 13. busbar 14 supported by the cable head 1 connected to the external load;
5 is stored, and these are connected to conductors 16, 17, 18,
19, 20, and 21, respectively.

Next, the vacuum circuit breaker 11 has an operation mechanism section 2 at the bottom.
2, and a shutoff section 23 that is opened and closed by the operating mechanism section 22 is provided at the top.

As shown in FIG. 2, the cutoff section 23 has a structure in which an upper electrode 24 is provided on the upper end surface of the insulating cylinder 2, and the vacuum valve 5 is supported via the upper electrode 24. Thus, the upper electrode 24 is fixed to the upper end surface of the insulating cylinder 2 with a screw 4, passes through a fixed current-carrying shaft 6 of the vacuum valve 5, and is tightened with a nut 7 to support the vacuum valve 5. A first electrode member 25 having a substantially similar configuration, which is arranged on the upper part of this first electrode member 25 and fixed to the first electrode member 25 with a screw 26, and a nut 7 on the lower surface.
The second electrode member 2 formed with a recess 27a for
It consists of 7. Here, the outer circumferential surface of the second electrode member 27 is formed of a circular arc surface with two radii of curvature R1 and R2, and when the radius of curvature of the outer circumferential surface of the first electrode member 25 is R3, R1>R3 ,R
The relationship should be 2≒R3. In addition, screw 2
The position where 6 penetrates is set to be inside the arcuate surface of the radius of curvature R1.

When the upper electrode 24 is configured in this way, the first electrode member 25 is substantially the same as the conventional upper electrode 3 described above, so that it uniformly contacts the upper end surface of the insulating cylinder 2 and does not form a contact angle θ. Therefore, discharge can be suppressed, and since the radius of curvature R1 of the outer peripheral surface of the second electrode member 27 has a relationship of R1>R3 with respect to the radius of curvature R3 of the first electrode member 25, the upper electrode 24 Overall, the potential gradient is more relaxed than that of the conventional upper electrode 3. This has been confirmed through experiments by the present inventor. That is, compared to the case where only the first electrode member 25 is provided, the dielectric strength is approximately 15 to 20% when the first electrode member 25 and the second electrode member 27 are provided in an overlapping manner and R1=2R3.
Improved. From this, it can be seen that the dielectric strength can be further improved by increasing the relationship of R1/R3.

Therefore, the insulation distance between the vacuum circuit breaker 11 and the panel wall 8 can be reduced, and the gas-insulated closed switchboard can be downsized. On the other hand, when the insulation distance from the panel wall 8 is constant, the insulation performance of the rated voltage 66KV is maintained by the first electrode member 25, for example, the rated voltage
When maintaining the insulation performance of 77KV or 110KV, changes in the rated voltage can be easily accommodated by stacking the second electrode member 27 with R1/R3 in a corresponding relationship to form the upper electrode. . In other words, gas-insulated closed switchboards with a plurality of rated voltages can be provided with a constant insulation distance, which is convenient for standardization.

In particular, in a structure in which the interrupting parts of a vacuum circuit breaker are arranged in a three-phase horizontal direction (direction perpendicular to the plane of FIG. 1),
The width dimension of the gas-insulated closed switchboard can be reduced, which is advantageous when creating a series of the same width.

[Effects of the invention] Since the present invention is configured as described above,
The dielectric strength is improved by relaxing the potential gradient of the upper electrode attached to the upper part of the insulating cylinder, thereby making it possible to downsize the gas-insulated closed switchboard.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an example of the configuration of a gas-insulated closed switchboard related to the present invention, Fig. 2 is a side view partially cut away showing the interrupting part of the vacuum circuit breaker of the present invention, and Fig. 3 is a conventional FIG. 4 is a partially cutaway side view showing the interrupting part of the conventional vacuum circuit breaker, and FIG. 4 is an explanatory diagram showing the relationship between the voltage and the upper electrode of the conventional vacuum circuit breaker. 2... Insulating cylinder, 5... Vacuum valve, 11...
Vacuum circuit breaker, 22... operating mechanism section, 23... cutoff section, 24... upper electrode, 25... first electrode member, 27... second electrode member.

Claims (1)

[Claims for Utility Model Registration] (1) Consisting of an operating mechanism section and a shutoff section in which a vacuum valve is housed in an insulating cylinder, an upper electrode provided on the top of the insulating cylinder and supporting the vacuum valve is connected to the outer periphery. A vacuum circuit breaker characterized in that a plurality of electrode members having surfaces with different radii of curvature are provided one on top of the other, and an electrode member with a larger radius of curvature is arranged in an upper stage. (2) The vacuum circuit breaker according to claim 1, in which a vacuum valve is supported by the lowest electrode member.