JPH0243290B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to bushings used in electrical equipment, and particularly to improvements in the core slippage prevention structure of large bushings.

[Technical background of the invention and its problems]

Oil-impregnated paper capacitor bushings are made by wrapping insulating paper around the outer periphery of a cylindrical center conductor, inserting electrodes into the predetermined positions of the winding layer to form a capacitor core, and attaching this capacitor core to a supporting metal fitting and an upper insulator tube. ,
It is constructed by being housed together with insulating oil in a closed container consisting of a lower insulator tube, a head expansion chamber, etc.
Oil passage holes are provided above and below the center conductor so that the insulating oil in the sealed container circulates through the inside of the center conductor, thereby cooling the center conductor.

By the way, as electrical equipment has become larger and larger in capacity in recent years, the bushings used there have naturally become larger and larger in capacity. As the bushing becomes larger, the capacitor core also becomes longer and larger in diameter, and its weight also tends to increase. When the weight of the capacitor core increases, there is a risk that the winding of the capacitor core may become misaligned due to its own weight or vibration during transportation, blocking the oil passage hole provided in the center conductor and eliminating the circulation path for the insulating oil. Furthermore, if there is no circulation path for the insulating oil, the center conductor cannot be cooled sufficiently, resulting in an abnormal temperature rise and accelerated deterioration of the insulation of the capacitor core. Conventionally, an adhesive is applied to a capacitor core when insulating paper begins to be wound around a center conductor, and an adhesive is also applied appropriately during the winding of the capacitor core to prevent winding misalignment.

However, adhesion between the center conductor and the insulating paper alone cannot support the weight of the core, and applying too much adhesive can be electrically harmful, so care must be taken when applying the adhesive. figure,
This has resulted in the disadvantage that assembly work requires a great deal of time and effort.

[Purpose of the invention]

The present invention eliminates the drawbacks of the prior art, simplifies assembly, prevents winding of the capacitor core, reliably cools the center conductor, and provides a bushing with excellent mechanical and electrical properties. The purpose is to

[Summary of the invention]

For this reason, the present invention inserts a ring between the capacitor core and the lower clamp to prevent the capacitor core from slipping, which has a notch space communicating in the circumferential direction and an oil passage hole communicating with the notch space. It is characterized by being made to do.

[Embodiments of the invention]

Hereinafter, the present invention will be explained with reference to the drawings.

In FIG. 1, a cylindrical central conductor 1 and a capacitor core 2 wound around it are comprised of a cylindrical metal fitting 3, an upper insulator tube 4, and a lower insulator tube 5 that are concentrically arranged at predetermined intervals on the outer periphery of the central conductor 1. A lower clamp 6 for sealing the lower insulator tube and an expansion chamber 7 for sealing the end of the upper insulator tube are housed in an expansion chamber 7, and these are tightened and fixed together by a spring 8 housed in the expansion chamber 7. Further, insulating oil 9 is filled in the gap between the capacitor core 2, the metal fitting 3 surrounding the capacitor core 2, and the insulator tubes 4 and 5. Further, a ring 10 for preventing winding of the capacitor core from slipping is inserted between the lower end of the capacitor core 2 and the lower clamp 6 so as to cover the bare portion of the center conductor 1.

This ring 10 for preventing winding is manufactured to a length that allows for the shrinkage of the insulating paper of the capacitor core 2 due to drying, and the length direction adjustment process is performed to match the actual item at the assembly stage of the bushing. and installed. In addition, this ring 1 for preventing winding misalignment
0 is made of an insulating material such as a laminated insulator or a cast insulator into a cylindrical shape as shown in FIGS. It has a thickness commensurate with the insulation thickness. Furthermore, a part of the inner circumferential surface of this ring 10 has a notch space 11 that is thinned and communicates with the circumferential direction, and a plurality of oil holes that are communicated with the notch space 11. A passage hole 12 is drilled through it in the radial direction.

In the large bushing configured in this way, the insulation thickness of the capacitor core 2 is designed to prevent winding misalignment that occurs due to the increase in the weight of the capacitor core 2 and due to vibrations during transportation and operation. By inserting a ring 10 having a thickness commensurate with that, the weight of the capacitor core 2 can be supported by the thickness of the ring 10 in addition to the winding tightening force of the capacitor core 2 itself, and the winding of the capacitor core 2 can be used as a stopper. Misalignment can be prevented. Moreover, by being able to prevent winding misalignment of the capacitor core 2, an oil passage is secured, a circulation path for insulating oil is secured, and a cooling effect can be maintained.

Furthermore, the inner circumferential surface of the ring 10 is in close contact with the center conductor 1, and a portion of the inner circumferential surface is made thinner.
By providing the notch space 11 communicating in the circumferential direction, even if the oil passage hole 1a of the center conductor 1 and the oil passage hole 12 of the ring 10 are misaligned, the notch space 11
Since the insulating oil 9 flows in the direction of the arrow through the oil passage hole 1a of the center conductor 1 and the ring 10 during assembly,
It is not necessary to assemble the oil passage holes 12 of the ring 10 to match each other, and the ring 10 can be easily positioned and the assembly work can be performed easily. Further, by inserting the ring 10 over the bare portion of the center conductor 1, an electrically effective bushing can be obtained.

As shown in FIG. 3, if the lower end of the capacitor core 2 is tapered, the ring 1 has a tapered shape corresponding to the core shape.
By setting it to 0, the same effect as in the above embodiment can be obtained.

Further, although the above embodiments have been explained by taking center clamp type bushings as an example, it goes without saying that the same effects can be obtained when the present invention is applied to bolt tightening type bushings.

〔Effect of the invention〕

As described above, according to the present invention, a cylindrical center conductor and a capacitor core wound around the cylindrical center conductor are arranged at a predetermined interval in a cylindrical metal fitting, an upper insulator tube and a lower insulator tube arranged above and below the metal fitting. In the bushing that is housed, an upper inner diameter is formed to be the same as the outer diameter of the center conductor between the lower end of the capacitor core and a lower clamp that seals the lower insulator tube, and a part of the inner circumferential surface of the bushing is formed with a The ring is made thinner and has a notch space that communicates with the circumferential direction, and a ring with an oil passage hole that communicates with this notch space is inserted to cover the center conductor, making assembly easier. It is possible to provide a bushing that is simple, prevents winding misalignment of the capacitor core, reliably cools the center conductor, and has excellent mechanical and electrical properties.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a bushing showing one embodiment of the present invention, FIG.
FIG. 3 is a partial sectional view of a bushing showing another embodiment of the present invention. 1...Center conductor, 1a...Oil pipe hole of center conductor,
2... Capacitor core, 3... Cylindrical metal fitting, 4...
Upper insulator tube, 5...Lower insulator tube, 6...Lower clamp, 7...Head expansion chamber, 8...Spring, 9...
...Insulating oil, 10...Ring, 11...Notch space, 12...Oil pipe hole.

Claims (1)

[Claims] 1. A bushing in which a cylindrical center conductor and a capacitor core wound around the cylindrical center conductor are housed at a predetermined interval in a cylindrical metal fitting, an upper insulator tube and a lower insulator tube arranged above and below the metal fitting,
An upper inner diameter is formed between the lower end of the capacitor core and a lower clamp that seals the lower insulator tube, and the inner diameter of the upper part is the same as the outer diameter of the center conductor, and a part of the inner circumferential surface is formed with a thinner circumference. A bushing characterized in that a ring having a notch space communicating in the direction and having an oil passage hole communicating with the notch space is inserted so as to cover the center conductor.