JPH0315328B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a bushing attachment device to oil-filled equipment such as a transformer.

(Prior art) Bushings can be attached to oil-filled equipment such as transformers by fixing a band fitting with a mounting flange provided between the upper and lower insulator pipes of the bushing to the bushing pocket of the oil tank. However, as the bushings become larger, there is an increased risk that the bushings will break if vibrations are applied to the bushings due to earthquakes, etc., and if the upper insulator pipe breaks, the center conductor and lower insulator pipe may be damaged inside the oil tank. Various problems have arisen, such as the oil tank falling down and damaging the main equipment, and the oil in the oil tank gushing out, causing secondary disasters such as fire.

(Purpose of the Invention) The present invention solves these conventional problems and eliminates the risk of damage to the main unit or oil in the oil tank spouting out even if the upper insulator of the bushing is destroyed due to an earthquake or the like. It was completed for the purpose of attaching bushings to oil-filled equipment.

(Structure of the Invention) The present invention provides for installing an insulating cylinder having an internal shape similar to the external shape of the lower insulating tube of the bushing in a bushing pocket of oil-filled equipment, and having an opening at the lower end of the insulating cylinder. While fixing the terminal fitting to be sealed, a lower insulating tube having a contact fitting at the lower end that contacts the terminal fitting is suspended and supported inside the insulating tube with a predetermined distance between it and the insulating tube. A slit for oil circulation is provided at the contact portion between the contact fitting and the insulating cylinder, and an annular projection is provided on the outer periphery of the band fitting of the bushing to contact the inner surface of the insulating cylinder,
It is characterized in that an oil circulation slit is provided in that portion, and will be explained in detail below with reference to the illustrated embodiment.

In the figure, 1 is an oil-filled device in which a main device 3 such as a transformer is housed in an oil tank 2, and 4 is a bushing attached to a bushing pocket 5 of the oil-filled device 1. A center clamp type in which an upper insulator tube 6 on the middle side, a band fitting 7 with a mounting flange, and a lower insulator tube 8 on the oil side are tightened together via a center conductor 10 by a spring force in a head chamber 9. It is. At the upper end of the bushing pocket 5, a flange 11 is attached to the bolt 1.
At the center of the flange 11 is attached an insulating cylinder 13 having an internal shape similar to the external shape of the lower insulating tube 8 of the bushing 4. The insulating cylinder 13 is made of fiber-reinforced plastic made by reinforcing thermosetting resin such as epoxy resin, polyester resin, or polyamide resin with glass fiber, etc., and has excellent electrical insulation properties, is thin, and is air and oil resistant. It should have excellent blocking properties.
A terminal fitting 14 is fixed to the opening at the lower end of the insulating cylinder 13 so as to seal the opening.
The terminal fitting 14 has a lead wire 15 connected to the main device 3 on its lower surface, and a tube contact type connector 16 on its upper surface. The terminal fitting 14 is fixed to the insulating tube 13 with adhesive or the like, and a shield 18 with an O-ring 17 is fixed to the lower end surface of the terminal fitting 14, so that the oil inside the insulating tube 13 is completely connected to the oil in the oil tank 2. insulated. Inside this insulating tube 13, a band fitting 7 with a mounting flange is attached to the flange 1.
1 with bolts 19, the lower insulator tube 8 of the bushing 4 is suspended and supported with a predetermined gap between it and the inner surface of the insulating tube 13. A lower metal fitting 20 fixed to the center conductor 10 and a contact metal fitting 21 fixed to the lower metal fitting 20 and in contact with the connector 16 of the terminal metal fitting 14 are provided at the lower end of the lower insulator tube 8. The contact fitting 21 has an approximately disk-shaped outer shape, and a contact portion 22 between the contact fitting 21 and the lower inner surface of the insulating cylinder 13 is provided with oil circulation slits 23 at several locations. In addition, band metal fittings 7
An annular protrusion 24 is also protruded from the outer periphery of the insulating cylinder 13 and comes into contact with the inner surface of the upper part of the insulating cylinder 13, and slits 25 for oil circulation are similarly formed at several locations on the annular protrusion 24. In addition, 2
6 is a current transformer attached to the upper part of the band fitting 7;
27 is a pipe with a valve 28 connecting the inside of the insulating cylinder 13 and the vacuum pump, 29 is a pipe with a valve 30 for injecting degassed oil into the inside of the insulating cylinder 13, and 31 is a pipe with a valve 30 for sealing the oil. It is a removable joint that can be stopped.

This structure includes an insulating tube 13 having an internal shape similar to the outer shape of the lower insulating tube 8 of the bushing 4, and a bushing 4 suspended and supported with a predetermined gap inside the insulating tube 13. If deaerated oil is injected into the gap formed between the lower insulator tube 8 and the lower insulator tube 8, the oil will flow through the oil flow through the contact portion 22 between the insulating tube 13 and the contact fitting 21 at the lower end of the lower insulator tube 8. The oil flows into the entire interior of the insulating cylinder 13 through the slit 23, the oil distribution slit 25, etc., and produces an insulating effect. Furthermore, if the upper insulator tube 6 is destroyed due to an earthquake or the like, the bushing core 32 integrated with the center conductor 10, whose upper end was supported by the upper insulator tube 6 until then, loses its support and falls, and at the same time, the lower metal fitting 20, The contact fitting 21 and the lower insulator tube 8 will also fall downward. However, when the lower insulator tube 8 falls, the contact portion 22 and the annular protrusion 24 generate a frictional force, and the oil flows upward through the oil distribution slits 23 and 25 formed in these contact portions. It generates a large viscous resistance and absorbs the falling energy of the lower insulator tube 8. and lower insulator tube 8
is supported by an insulating cylinder 13 whose internal shape approximates its external shape by falling only a minute distance, and
Since the lower metal fitting 20 and the contact metal fitting 21 are received by the terminal fitting 14 that seals the opening at the lower end of the insulating tube 13, even if the bushing 4 is destroyed, the damage is limited to the inside of the insulating tube 13, and the main device 3 There will be no damage to the oil tank 2 or any debris will be scattered into the oil in the oil tank 2. Moreover, the insulation tube 13
Since the inside of the vacuum pump is completely sealed, there is no risk of oil gushing out and causing secondary disasters such as fire.In addition, when repairing, clean the inside of the insulating tube 13, install a new bushing, and replace the vacuum pump with a new bushing. It has the advantage of being easy to repair, as it is only necessary to deaerate the oil and then inject the deaerated oil, and only a small portion of the entire body needs to be replaced.

(Effects of the Invention) As is clear from the above explanation, even if the upper insulating pipe of the bushing is destroyed due to an earthquake, the effect remains within the insulating cylinder, and the main equipment may be damaged or the inside of the oil tank may be damaged. Since the oil does not gush out and has the advantage of being easy to repair, it will greatly contribute to the development of the industry as a bushing attachment device for oil-immersed equipment that solves the problems of conventional products. .

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, and FIG. 2 is a partially cutaway enlarged front view showing the main parts thereof. DESCRIPTION OF SYMBOLS 1... Oil-filled equipment, 4... Bushing, 5... Bushing pocket, 8... Lower insulator tube, 13... Insulating cylinder, 14... Terminal fitting, 21... Contact fitting, 22... Contact part, 23 ...Slit for oil distribution.

Claims (1)

[Claims] 1. An insulating tube 13 having an internal shape similar to the outer shape of the lower insulating tube 8 of the bushing 4 is installed in the bushing pocket 5 of the oil-filled device 1, and the opening at the lower end of the insulating tube 13 is Terminal fitting 1 for sealing the opening
4 is fixed, and inside the insulating tube 13, a lower insulating tube 8 having a contact fitting 21 at its lower end that contacts the terminal fitting 14 is suspended and supported with a predetermined distance between it and the insulating tube 13. At the same time, an oil flow slit 23 is provided at the contact portion 22 between the contact fitting 21 and the insulating tube 13, and an annular projection 24 is provided on the outer periphery of the band fitting 7 of the bushing 4 to contact the inner surface of the insulating tube 13. Oil distribution slit 25
A bushing attachment device for oil-filled equipment, characterized by being provided with. 2. The bushing attachment device for oil-immersed equipment according to claim 1, wherein the insulating tube 13 is made of fiber-reinforced plastic.