JPH0343851B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rubber/plastic insulated power cable terminal part, and more particularly, to a structure of a rubber/plastic insulated power cable terminal part filled with insulating oil. It is.

[Prior Art] Conventionally, a rubber-plastic insulated power cable terminal part is filled with insulating oil and has a reservoir therein as a hydraulic compensator.
A structure as shown in the figure is generally adopted. That is, the cable 6 that has passed through the opening 15a of the immovable member 15 is sealed watertightly with the sleeve 1 fixed to the immovable member 15 at the portion where the compensating insulating paper 6a and the epoxy bell mouth 6b are attached. Part 1
The lower part of the cable 5 is watertightly covered and sealed with the protection tube 2 and the end copper tube 7, and the insulating oil 5 is filled in the jacket tube 1, the protection tube 2, and the end copper tube 7. There is. The protection tube 2 is formed of a small diameter cylindrical part 2a having a flange 2c for attachment to the immovable member 15 at the upper opening edge, and a large diameter cylindrical part 2b connected to the lower part of the small diameter cylindrical part 2a. and the large-diameter cylindrical portion 2b are connected by an upper flange 8, and the lower end opening of the large-diameter cylindrical portion 2b is covered with a lower flange 9 facing the upper flange 8. The end copper pipe 7 has a mounting flange 7a at the upper opening edge fixed to the lower flange 9 of the protective tube 2, and a small diameter opening at the lower part is fixed to the cable 6 in a watertight manner by an insulating member 16. ing.

On the lower flange 9 in the large-diameter cylindrical portion 2b of the protection tube 2, a hydraulic compensator is disposed, for example, a well-known bellows-type reservoir 3 in which gas 4 is sealed.

[Problems to be Solved by the Invention] By the way, in the structure of the conventional rubber/plastic insulated power cable terminal section configured as described above, the reservoir used as the pressure compensator is filled in the terminal section. The insulating oil 5 is not installed in a particularly partitioned or designated area, and as a result, the reservoir 3 may malfunction for some reason and the gas 4 in the reservoir may leak into the insulating oil. If the gas leaks into the terminal, the leaked gas becomes bubbles and moves upward inside the terminal, causing partial discharge and internal flash shorting in the high electric field area, and in the worst case, dielectric breakdown. There was a risk that this would have a very undesirable adverse effect on the electrical insulation properties.

[Means for Solving the Problems] An object of the present invention is to solve the above-mentioned drawbacks of the conventional terminal section, so that even if a pressure compensating device such as a reservoir should cause a gas leak due to an unexpected accident, electricity will be maintained. It is an object of the present invention to provide a structure of a terminal part for a rubber/plastic insulated power cable, which can suppress the rise of air bubbles that have a direct adverse effect on characteristics, and can prevent insulation breakdown accidents.

The terminal part according to the present invention is provided with an inner cylinder that forms a gas reservoir in the upper part of the reservoir, which is disposed inside the protective tube and serves as a pressure compensator.

[Function] When the gas sealed in the reservoir leaks, the inner cylinder installed in the protection tube prevents the gas bubbles from rising, and the gas bubbles are trapped between the upper part of the reservoir and the ceiling wall of the protection tube. The gas accumulates in the gas reservoir formed in the

[Examples] The present invention will be described below with reference to illustrated examples.

FIG. 1 is a cross-sectional view of a rubber-plastic insulated power cable terminal section showing a first embodiment of the present invention, in which only essential parts of the present invention are shown. As is clear from FIG. 1, in the terminal part according to the present invention, inside the reservoir 3 as a pressure compensator, which is disposed inside the large diameter cylindrical part 2b of the protective tube 2, A hanging inner cylinder 10 is integrally formed on the inner peripheral edge of the upper flange 8 of the protection tube 2 so as to be airtight.

When the inner cylinder 10 is arranged in this way, a gas reservoir part 12 is formed in the upper part of the reservoir 3, which is a canopy-shaped space surrounded by the peripheral wall of the protective tube 2, the protective tube upper flange 8, and the peripheral wall of the inner cylinder 10. be done. Therefore, when the sealed gas 4 of the reservoir 3 leaks, the inner cylinder 10 acts as a partition and the gas bubbles do not rise to the end of the cannula 1 (see Fig. 4). The bubble gas remains in the reservoir 12.
Therefore, electrical insulation breakdown accidents at the terminal portion can be prevented.

Note that even if the inner cylinder 10 is provided in this way, the insulating oil 5 filled at the end part is insulated around the reservoir 3 due to the gap 11 formed between the lower flange 9 of the protective tube 2 and the inner cylinder 10. Since it is continuous with oil, it does not affect the function as a hydraulic compensator in any way.

FIG. 2 shows a modification of the rubber/plastic insulated power cable terminal section of the first embodiment of the present invention shown in FIG. 1 above. In the first embodiment, the inner cylinder 10 is connected to the protection tube upper flange 8.
However, from the viewpoint of manufacturing and assembly workability, this is not formed integrally with the protection tube upper flange 8, and as shown in FIG.
is formed of a molded product separate from the upper flange 8 and has a mounting flange on its upper peripheral edge, and is attached to the upper flange 8 with a tightening screw 17 via a packing 13 to maintain airtightness. It is designed to be fixed.

This makes installation and removal easy and manufacturing costs low.

FIG. 3 is a cross-sectional view of a rubber-plastic insulated power cable terminal section showing a second embodiment of the present invention. This embodiment takes into consideration the case where the internal volume of the protective tube 2 alone is insufficient for the volume required for the gas reservoir section 12.

That is, when the internal volume is insufficient in this way, the lower end of the inner tube 10B is extended to the inside of the end copper tube 7 connected below the protective tube 2. With this configuration, the inner cylinder 10B acts as a partition not only within the protection tube 2 but also within the end copper tube 7, so that the upper space within the end copper tube 7 also functions as the gas reservoir portion 14. Therefore, the deficiency in the internal volume of the protection tube 2 can be compensated for.

[Effects of the Invention] As described above, according to the present invention, the sealed gas 4 is removed from the reservoir 3 incorporated as a pressure compensator for the insulating oil 5 filled in the terminal portion for some reason.
Even if the gas bubbles leak, the inner cylinder 10,
Since the gas remains in the gas reservoirs 12 and 14 formed by the action of the gases 10A and 10B, the leaked gas will not reach the high electric field area, and electric properties such as this can prevent electrical breakdown accidents. A stable terminal section can be provided.

Further, an inner cylinder 1 for forming a gas reservoir according to the present invention
Since 0, 10A, and 0B are provided inside the reservoir 3, they have the effect of protecting the inside part of the reservoir 3, and also prevent the terminal cable 6 from being damaged by the inner protruding part of the reservoir 3. be effective.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part of a rubber/plastic insulated power cable terminal section showing an embodiment of the present invention, and FIG. 2 is a main part of a terminal section showing a modification of the embodiment shown in FIG. 1 above. 3 is a sectional view of a main part of a rubber/plastic insulated power cable terminal section showing another embodiment of the present invention, and FIG. 4 is a conventionally used rubber/plastic insulated power cable terminal section. FIG. 1... Mantle tube, 2... Protection tube, 3... Reservoir, 4... Filled gas, 5... Insulating oil, 6... Cable, 7... End copper tube, 8... Protection tube upper flange, 9 ... Protection tube lower flange, 10, 10A,
10B...Inner cylinder, 12, 14...Gas reservoir section.

Claims (1)

[Scope of Claims] 1. In a rubber/plastic insulated power cable terminal portion having a filling insulation oil pressure compensating device inside, such as a reservoir, etc., inside the reservoir in a protective tube in which the reservoir is arranged, inside the reservoir. A terminal part for a rubber/plastic insulated power cable, which is provided with an inner cylinder that forms a gas reservoir in the upper part of the reservoir when the sealed gas leaks. 2. When the internal volume of the protection tube is small, the inner cylinder is extended to the inside of the end copper tube connected below the protection tube, and a gas reservoir is also provided in the upper part of the same end copper tube. A rubber-plastic insulated power cable termination according to claim 1, characterized in that it is adapted to form a rubber-plastic insulated power cable terminal.