JPH0145685B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas bushing used for insulating the lead wires of electrical equipment such as transformers, capacitors, oil fillers, disconnectors, etc. from a container box and leading them out to the outside.

Conventional gas bushings of this type include a first example shown in FIG. 1, a second example shown in FIG. 2, and a third example shown in FIG. 3.

In Fig. 1, 1 is an insulating jacket, 2 is a central conductor that is supported through the center of the insulating jacket 1, and 3 is a grounded metal jacket of an electrical equipment to which the insulating jacket 1 is attached, such as an SF ₆ gas-insulated switchgear. It is. Reference numeral 4 denotes a high-voltage lead wire of the electrical equipment, which is electrically connected to the center conductor 2 via, for example, a tube-shaped contact 5. Reference numeral 6 denotes a shield electrode provided within the electrical equipment so as to be located at the connection portion. Although this shield electrode 6 is not necessarily required, in this example it is configured to have the same potential as the ground metal jacket 3. There is.

The insulating jacket 1 and the substrate 2a of the center conductor 2, and the insulating jacket 1 and the ground metal jacket 3 are connected airtightly and firmly by a known method using, for example, an O-ring and a bolt. 7 is SF ₆ gas filled in the insulating jacket 1 and the grounded metal jacket 3 at, for example, 4 atmospheres.

Further, in FIG. 2 showing a second example of a conventional gas bushing, 31 is a center conductor having a male screw 32 formed at its upper end, and 33 is a capacitor core that is firmly and airtightly fixed concentrically to this center conductor 31. , 34 is a plurality of concentric cylindrical electrodes for voltage distribution control, 35 is a main insulator made of, for example, epoxy resin-impregnated paper, and the concentric cylindrical electrode 34 and the main insulator 35 are
A capacitor core 33 is formed by this. 36
is a lower flange, which is firmly and airtightly fixed concentrically to the capacitor core 33. By integrating the center conductor 31, capacitor core 33, and lower flange 36, a bushing known as a so-called resin-impregnated paper capacitor bushing is formed. 37 is an insulating sleeve, and 38 is an upper flange. A female thread 39 is formed in the center of the upper flange 38 to be screwed into the male thread 32.
Then, the upper part of the resin-impregnated paper capacitor bushing is inserted into the insulating sleeve 37, and the upper flange 38 is screwed onto the center conductor 31.
is tightened and fixed between the upper flange 38 and the lower flange 36. Although not shown, the contact surfaces between the insulating sleeve 37 and the upper and lower flanges 36 and 38 are kept airtight with gaskets or the like. Male thread 32
For example, a semi-dry liquid sealing material is infiltrated and hardened into the threaded portion between the female screw 39 and the female thread 39 to maintain airtightness.
The internal space 40 is filled with SF ₆ gas at, for example, 4 atmospheres.

Furthermore, in FIG. 3 showing a third example of the conventional gas bushing, 41 is an insulating spacer made of, for example, a filled epoxy resin cast product, which is firmly and airtightly fixed concentrically to the center conductor 31. be. 42 is a capacitor core, 43 is a plurality of concentric cylindrical electrodes for voltage distribution control, and 44 is, for example, an SF ₆ gas foam insulation molded body, which is formed by appropriately pressurizing, for example, an uncured cycloaliphatic epoxy resin material. After blowing SF ₆ gas and stirring to sufficiently infiltrate the SF ₆ gas, the pressure is slightly reduced to create a large number of SF ₆ gas bubbles in the liquid resin material, which is then foamed and then cured. It is. This insulating molded body 44 has properties such as a lower dielectric constant, flexibility, and ease of metal embedding molding than a solid insulator made of resin alone. The center conductor 31 is passed through and supported by the capacitor core 42, and the capacitor core 42 is connected to the insulating sleeve 37 and the lower flange 36.
By fitting the upper flange 38 into the center conductor 31, the lower flange 36 and the insulating sleeve 37 are tightened and fixed between the insulating spacer 41 and the upper flange 38. The method of airtightness and the filling of SF ₆ gas into the internal space 40 are the same as in the second example.

Since the first example of the conventional gas bushing is configured as described above, if an arc 10 occurs between the center conductor 2 and the shield electrode 6 as shown in FIG. may move, for example, in the direction of arrow A and touch the inner surface of the insulating sleeve 1. Since the insulating mantle 1 is filled with SF ₆ gas at about 4 atmospheres, if the insulating mantle 1 is broken due to the high heat of the arc 10, its fragments may be scattered around.

Furthermore, in the second example, especially for high-voltage bushings, the manufacturing equipment is large and many materials are used. In the third example, the inside of the bushing is filled with an insulating molded body foamed with an insulating gas, and compared to the first example, there is almost no chance that an arc of SF ₆ gas corresponding to an arc of 10 will occur. Therefore, it is superior to the first and second examples in that there is less opportunity for the arc to come into direct contact with the inner surface of the insulating jacket 37, and almost no large-scale manufacturing equipment is required as in the second example. . However, the center conductor 31 and the lower flange 3
Since the SF ₆ gas foam insulation molded body 44 is bridged between the center conductor 31 and the lower flange 36 to form the main insulation, if a dielectric breakdown occurs between the center conductor 31 and the lower flange 36 and a short circuit current flows, the normal Similar to the through-hole breakdown of fixed organic insulators, a conductive trace path is formed, so permanent failure is likely even if the short-circuit current is removed in a short time.

The present invention has been made to eliminate the above-mentioned drawbacks, and includes a lining layer made of a foamed insulating molded product adhered to the inner surface of the insulating sleeve, and an insulating gas, e.g. By filling the main insulation with SF ₆ gas at approximately 4 atm, the purpose is to prevent arcs from coming into direct contact with the insulation sleeve and to provide a gas bushing with less chance of permanent failure due to arcs. do.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 4 shows a first embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals. In Figure 4, 2
0 is a lining layer made of a foamed insulating molded material applied to the inner surface of the insulating sleeve 1. This lining layer 20 is constructed by, for example, placing an insulating molded body made of the same material as the SF ₆ gas foamed insulating molded body described in the third conventional example in close contact with the inner surface of the insulating sleeve 1.

The first embodiment of the present invention has the above-described configuration, in which an arc 10 is generated between the center conductor 2 and the shield electrode 6, and the arc 10 moves, for example, as indicated by the arrow A, and the lining layer 20 Even if it comes into contact with the insulating jacket 1, no thermal shock will be applied to the insulating jacket 1 due to the heat insulating effect of the SF ₆ gas foam insulation molded body.

If the arc generation time is short, the time the arc is in contact with the lining layer 20 is also short, and the surface of the lining layer 20 is only slightly damaged.
Further, the voltage between the center conductor 2 and the ground metal jacket 3 is applied to the lining layer 20 in the longitudinal direction of the bushing, but since the dimension in the longitudinal direction is large, the surface of the lining layer 20 has only a small dimension. Even if it is damaged to the point where it loses its insulation properties, it is unlikely that its withstand voltage performance will be significantly reduced. Furthermore, the center conductor 2
Although the dimension between the shield electrode 6 and the bushing is shorter than the longitudinal dimension of the bushing, since the main insulation 7 is provided between the two and the shield electrode 6 with an insulating gas, the insulation performance is quickly restored after the arc is extinguished. . Therefore, permanent damage as in the third conventional example described above is unlikely to occur. Note that the arc can be extinguished by disconnecting the electrical equipment from the power system.

FIG. 5 shows a second embodiment of the present invention, in which the same parts as in FIGS. 1 and 4 are given the same reference numerals. Fifth
In the figure, reference numeral 21 denotes an auxiliary insulating tube made of, for example, glass epoxy resin, arranged concentrically within the insulating sleeve 1;
Reference numeral 22 denotes insulating particles foamed with an insulating gas filled in the gap between the insulating sleeve 1 and the auxiliary insulating cylinder 21. This embodiment uses the auxiliary insulating cylinder 21 and the insulating particles 2.
2 constitutes a lining layer 20. Note that since the auxiliary insulating cylinder 21 is for holding the insulating particles 22 between it and the insulating sleeve 1, it may have a small mechanical strength and may be mesh-like.

In the second embodiment of the present invention, the arc 10 is generated between the center conductor 2 and the grounded metal jacket 3, moves as indicated by the arrow A, and moves toward the auxiliary insulating tube 21. Even if the inner surface of the insulating sleeve 1 is touched, no thermal shock will be applied to the insulating sleeve 1 due to the heat insulating effect of the foamed insulating molded body. When the arc generation time is short, the time during which the arc 10 is in contact with the auxiliary insulating cylinder 21 is also short, and the surface thereof is only slightly damaged. Therefore, like the first embodiment, permanent damage is unlikely to occur.

As described above, according to the present invention, a lining layer of a foamed insulating molded body is provided on the inner surface of the insulating sleeve, and an insulating gas is filled between the lining layer and the center conductor to form the main insulation. It can effectively significantly reduce the risk of uneven heat breakdown due to internal arcing of the insulating jacket in gas bushings, and if the internal arc generation time is extremely short, there is a greater possibility that this gas bushing can be used continuously. ,
It has a remarkable effect as a gas butsing.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view showing a first example of a conventional gas bushing, Fig. 2 is a longitudinal sectional view showing a second example of a conventional gas bushing, and Fig. 3 is a third example of a conventional gas bushing. FIG. 4 is a longitudinal sectional view showing a first embodiment of the gas bushing of the present invention, and FIG. 5 is a longitudinal sectional view showing a second embodiment. DESCRIPTION OF SYMBOLS 1... Insulating jacket, 2... Center conductor, 3... Ground metal jacket, 4... High voltage leader wire, 5... Tulip contact, 6... Shield electrode, 7... Main insulation, 10 ... Arc, 20 ... Lining layer, 21 ...
...Auxiliary insulating tube, 22...Insulating particles. In addition, in the figure,
The same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. an insulating jacket, a center conductor that is supported through the center of the insulating jacket and connected to the lead wire of the electrical equipment;
A lining layer made of a foamed insulating molded material is adhered to the inner surface of the insulating jacket to prevent thermal shock caused by an arc, and a main conductor is formed by filling an insulating gas between the lining layer and the center conductor. Gas bushing with insulation.