JPH0738291B2 - Gas insulated switchgear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a high-voltage electrode part of an insulating cylinder connecting between high-voltage electrode parts or connecting a high-voltage electrode part and a ground potential part. The present invention relates to a gas-insulated switchgear with an improved mounting structure.

(Prior Art) Conventionally, in a gas-insulated switchgear, when a high-voltage electrode part is insulated and supported between high-voltage electrode parts or a low-voltage part, a method of using an insulating cylinder is generally used. This support structure will be described by taking the arc extinguishing chamber of the puffer type gas circuit breaker shown in FIG. 5 as an example. Generally, the arc extinguishing chamber of the puffer type gas circuit breaker is composed of a movable electrode portion and a fixed electrode portion which are arranged so as to come in contact with and separate from each other, and FIG. 5 shows the open state thereof. That is, the movable electrode portion fixes the puffer piston 3 inside the movable portion support 2 to which the conductor 1 is connected, surrounds the puffer piston 3, and between the puffer piston 3 and the movable portion support 2 the puffer cylinder 4 is provided.
Is slidably mounted. Also, an insulating nozzle 5, a movable energizing electrode 6 on the outer peripheral side of the insulating nozzle 5, and a movable arc electrode 7 on the inner peripheral side are fixed to the end surface of the puffer cylinder 4 on the fixed electrode side. It is configured to be connected to and driven by an operating device via an operating rod 8 and an insulating rod (not shown). In addition, the movable portion support 2 is fixed to the ground container via a support insulating cylinder (not shown).

On the other hand, the fixed electrode part is the fixed part support 10 to which the conductor 9 is connected.
In addition, the fixed energization electrode 11 and the fixed arc electrode 12 are fixed to the positions facing the movable energization electrode 6 and the movable arc electrode 7, respectively. Further, an insulating cylinder 13 is attached so as to surround such a movable electrode portion and a fixed electrode portion. Embedded metal fittings 14 are provided on both ends of the insulating cylinder 13 by integral casting, and the movable electrode support 2 and the fixed part support 10 are bolted to the embedded metal fitting 14 to fix the fixed electrode portion. An arc extinguishing chamber is formed by being insulated and supported by the movable electrode portion. Further, the insulating cylinder 13
The embedded metal fittings 14 arranged at both ends of the
An outer shield 15 is attached so as to surround 13.
Further, in order to suppress the thermal stress at the time of casting the insulating cylinder 13, the embedded metal fitting 14 is generally arranged by disposing rod-shaped metal fittings each provided with one female screw in a distributed manner by the number of bolts. Is.

(Problems to be Solved by the Invention) By the way, the purpose of mounting the outer shield 15 in the arc extinguishing chamber of the puffer type gas circuit breaker having the above-mentioned configuration is to:
Tip of embedded metal fitting 14, movable part support 2 and fixed part support
10 is to alleviate the electric field in the portion in contact with the insulating cylinder 13. That is, when the outer shield 15 is not provided, the tip of the embedded metal fitting 14 has a structure projecting to the opposing electrode side, so that the electric field increases and an internal flash occurs. Further, in the portion where the movable portion support 2 and the fixed portion support 10 are in contact with the insulating tube 13, it is impossible for the insulator and the high-voltage conductor to be completely in close contact with each other over the entire circumference, and there is always a small amount between them. A gap is created. When such a minute gap exists, the electric field of the high-voltage conductor becomes the dielectric constant ratio of the insulating cylinder to the surrounding insulating gas times the electric field when the insulator and the high-voltage conductor are in complete contact. . For example, in the case of SF ₆ gas and epoxy insulating cylinder, the electric field of the high-voltage conductor in the presence of the minute gap is 6 times that in the case of perfect adhesion. For this reason, embedded metal fittings
The electric field is relaxed by the portion where 14 is arranged, but the electric field becomes higher due to the existence of the minute gap in the middle portion of the metal fitting which is dispersed as described above, and the insulating cylinder A surface flashover occurs along the inner or outer surface of 13.

Therefore, the external shield 15 for electric field relaxation is provided outside the insulating cylinder.
Since the external shield 15 is arranged so as to surround the insulating cylinder 13, the diameter of the high-voltage electrode section becomes large, and thus the gas-insulated switchgear is provided. This has led to an increase in the size of the device.

Further, when a conductive foreign substance adheres between the outer surface of the insulating cylinder 13 and the inner surface of the outer shield 15, there is a possibility that a creeping flashover may occur along the outer surface of the insulating cylinder from the starting point of the foreign substance. In order to prevent this, it is customary to provide a gap between the insulating cylinder and the outer shield, and as a result, the outer diameter of the outer shield and the outer diameter of the high-voltage electrode portion are large.

The present invention has been proposed in order to solve the above drawbacks, and an object thereof is to provide a gas-insulated switchgear that improves withstand voltage performance, reduces the number of parts, and enables reduction in size. Especially.

[Structure of the Invention] (Means for Solving the Problems) The present invention connects between high-voltage electrode parts in a container in which an insulating gas is sealed, or connects the high-voltage electrode parts and a ground potential part with an insulating cylinder. In the gas-insulated switchgear configured as described above, a plurality of embedded metal fittings connected to the high-voltage electrode portion are provided at least at one end on the high voltage side of the insulating cylinder, and the embedded metal fitting on the central side of the insulating cylinder. An inner shield that surrounds the tip portion and is configured to have the same potential as the high-voltage electrode portion is provided so as to be connected to the embedded metal fitting, and further, the outer diameter of both ends of the insulating cylinder is The outer diameter of the insulating tube connecting portion of the high-voltage electrode portion is smaller than that of the insulating tube connecting portion.

(Operation) According to the gas-insulated switchgear of the present invention, the electric field at the tip of the embedded metal fitting is mitigated by the internal shield arranged so as to surround the metal fitting, and the insulating cylinder and the high-voltage electrode portion are connected. The electric field at the joint surface with the member is mitigated over the entire circumference of the insulating cylinder by the combined shield effect of the inner shield and the connecting member itself of the high-voltage electrode section, so that the conventionally used outer shield is unnecessary. be able to.

(Embodiment) An embodiment of the present invention will be specifically described below with reference to FIGS. 1 to 4. The same members as those of the conventional type shown in FIG. 5 are designated by the same reference numerals, and the description thereof will be omitted.

In the present embodiment, as shown in FIG. 1, a plurality of embedded metal fittings 14 for bolting to the movable part support 2 or the fixed part support 10 are arranged at both ends of the insulating cylinder 20, respectively.
A cylindrical inner shield 21 is formed by integral casting so as to surround the tip of the embedded metal fitting 14. As shown in FIG. 2, the inner shield 21 includes a ring-shaped metal shield 22 arranged on the central portion side of the insulating cylinder with respect to the tip of the embedded metal fitting 14 and a metal net.
It is configured to be electrically and mechanically connected to a cylindrical metal mesh shield 23 formed by winding so as to be in contact with the outer periphery of the same by brazing or the like.

Further, small diameter portions 24 having a diameter D ₂ smaller than the outer diameters of other portions of the insulating cylinder 13 are formed at both ends of the insulating cylinder 13. Further, the outer diameter D ₁ of the insulating tube connecting portion of the movable portion support 2 and the fixed portion support 10 connected to both ends of the insulating tube 13 is formed to be substantially the same as the outer diameter of the insulating tube, It is configured to be larger than the outer diameter D _{2 of the} portion. Furthermore, the inner shield
When the distance between the end of the movable portion support 2 or the fixed portion support 10 on the side of 21 and the connection end face of the insulating tube is L, L ≦ 3 (D ₁ −L ₂ ) is satisfied.

In the gas-insulated switchgear of this embodiment having such a configuration, the embedded metal fitting 14 and the inner shield 21 that are electrically connected to each other, via the bolt screwed into the embedded metal fitting 14,
It has the same potential as the movable part support 2 or the fixed part support 10. Therefore, the electric field at the tip of the embedded metal fitting 14 is mitigated by the inner shield 21 arranged so as to surround it.

On the other hand, as shown in FIG. 3, the electric field is also relaxed in the intermediate portion of the embedded metal fittings 14 arranged at appropriate intervals as described below. That is, FIG. 4 shows the relationship between the electric field on the outer peripheral side (point A in FIG. 3) of the joint surface between the insulating cylinder 13 and the movable portion support 2 or the fixed portion support 10 and L / (D ₁ −D ₂ ). However, as can be seen from the figure, if L / (D ₁ −D ₂ ) is set to 3 or less, the electric field at the point A in the middle portion of the embedded metal fitting 14 is arranged all around the insulating cylinder 13. The combined effect of the inner shield 21 and the outer circumference of the insulating cylinder joint portion of the movable portion support 2 or the fixed portion support 10 is sufficiently relaxed. It is needless to say that the shield effect becomes larger and the electric field becomes lower than the point A in the portion inside the point A in FIG.

As described above, in the arc extinguishing chamber of the puffer type gas circuit breaker according to the present embodiment, the electric field mitigating action at the two places of the tip of the embedding metal fitting and the joint between the insulating cylinder and the movable part support or the fixed part support causes the embedding Internal flash of the insulating cylinder 13 starting from the tip of the metal fitting 14, and the insulating cylinder 13, the movable part support 2 and the fixed part support 10
Since it is possible to prevent a creeping flashover starting from a minute gap portion of the joint surface with, it is possible to eliminate the need for an external shield conventionally arranged on the outer circumference of the insulating cylinder. Also,
By forming the outer diameter D ₂ of both ends of the insulating cylinder 13 to be smaller than the outer diameter of the insulating cylinder 13 in the portion where the inner shield 21 is disposed, the insulating cylinder 13 mounting portion of the movable part support 2 and the fixed part support 10 is formed. It is possible to suppress an increase in the outer diameter D ₁ of the above, and the outer diameter of this portion can be made substantially equal to the outer diameter of the insulating cylinder in the portion where the inner shield 21 is arranged. Further, at the joint surface between the insulating cylinder 13 and the movable portion support 2 and the fixed portion support 10, the electric field of the conductive portion and the electric field in the creeping direction of the insulating cylinder are low both inside and outside of the insulating cylinder 13. Even if foreign matter adheres, creeping flashover of the insulating cylinder 13 originating from this does not occur. Since the end portion of the inner shield 21 on the side of the insulating cylinder central portion is composed of a ring-shaped metal shield 22 and has an R shape, the electric field at this portion also has a low value, leading to an internal flashover. Can be prevented. The position of the metal shield 22 is
It can be set freely by appropriately adjusting the length of the metal mesh shield 23, and by optimizing this position, the electric field of the electrode inside the insulating cylinder 13 can be relaxed. Furthermore, since the metal mesh shield 23 has a flexible structure in which fine wires are meshed, the mesh is deformed following the surrounding insulator, and the insulators on both sides of the mesh are formed by the insulators inserted between the fine wires. Connected to each other. For this reason, there is no risk of an increase in thermal stress when casting the insulating cylinder 13 and a decrease in strength with respect to the load during operation of the gas circuit breaker.

As described above, according to the present embodiment, the external shield disposed on the outer circumference of the insulating cylinder is unnecessary, the outer diameter of the arc extinguishing chamber can be reduced, and the electric field of each electrode inside the insulating cylinder is also reduced. Since it can be relaxed, the withstand voltage performance can be significantly improved.

It should be noted that the present invention is not limited to the above-described embodiment, and the same effect can be obtained even if a shield formed by winding a thin wire in a ring shape is used as the metal shield 22. Further, the ring-shaped metal shield 22 may be omitted by forming the end portion of the metal mesh shield 23 on the insulating cylinder central portion side into an R shape.

In addition, although the above-mentioned embodiment describes the case where the present invention is applied to the puffer type gas circuit breaker, it can be appropriately applied to the one in which the high voltage electrode part is supported from the ground potential part using the insulating cylinder,
Moreover, the same effect can be obtained.

[Effects of the Invention] As described above, according to the present invention, at least one end of the insulating cylinder on the high voltage side is provided with a plurality of embedded metal fittings connected to the high voltage electrode portion, and An inner shield that surrounds the tip of the central portion of the insulating cylinder and is configured to have the same potential as the high-voltage electrode portion is connected to the embedded metal fitting and is disposed. The gas insulation that improves the withstanding voltage performance, reduces the number of parts, and can be downsized by a simple means that the outer diameter of the is smaller than the outer diameter of the insulation tube connection part of the high-voltage electrode part. A switchgear can be provided.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an arc extinguishing chamber of a puffer type gas circuit breaker to which an insulating cylinder mounting structure of a gas insulated switchgear according to the present invention is applied, and FIG. 2 is an enlarged sectional view showing an essential part of FIG. Figure 3 is the first
An enlarged sectional view of an essential part showing an intermediate part of the embedded metal fitting in the figure,
FIG. 4 shows the electric field at point A in FIG. 3, the internal shield,
FIG. 5 is a side cross-sectional view showing the mutual positional relationship between the outer peripheral end of the insulating cylinder and the outer periphery of the insulating cylinder mounting portion of the high-voltage electrode portion, and FIG. 5 is a side view showing the arc extinguishing chamber of the conventional puffer type gas circuit breaker. 1 ... Conductor, 2 ... Moving part support, 3 ... Puffer piston, 4 ... Puffer cylinder, 5 ... Insulation nozzle, 6 ...
... movable energizing electrode, 7 ... movable arc electrode, 8 ... operating rod, 9 ... conductor, 10 ... fixed part support, 11 ... fixed energizing electrode, 12 ... fixed arc electrode, 13 ... insulating tube, 14 …… Embedded metal fittings, 15 …… External shield, 20 …… Insulation cylinder, 21 ……
Inner shield, 22 …… Metal shield, 23 …… Metal mesh shield, 24 …… Small diameter part.

Claims (1)

[Claims] 1. A gas-insulated switchgear in which a high-voltage electrode section is connected between a high-voltage electrode section or a high-potential electrode section and a ground potential section in an insulating gas-sealed container by an insulating tube. A plurality of embedded metal fittings connected to the high-voltage electrode portion are provided at one end on the high-voltage side, and the distal end portion of the embedded metal fitting on the central side of the insulating cylinder is surrounded, and the high-voltage electrode portion. An inner shield configured to have the same electric potential as that of the first embodiment is connected to the embedded metal fitting and disposed, and the outer diameter of both ends of the insulating cylinder is the outer diameter of the insulating cylinder connecting portion of the high-voltage electrode portion. A gas-insulated switchgear characterized by being made smaller.