JPS642493Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a sealing structure applied to a portion where a conductor passes through a sleeve of the termination box in a termination box that directly connects the terminal portion of a power cable to equipment.

Termination boxes that seal the cable system side and the equipment side are used at the terminal portions of various power cables that connect to equipment.

As shown in FIG. 1, in the conventional termination box, the seal 2 of the power cable 1 is removed, a reinforcing insulator 4 is continuously applied to the outer periphery of the exposed cable core 3, and a conductor pull-out rod 6 is attached to the cable conductor 5. are connected by means such as crimping, and an epoxy resin sleeve 7 is fitted over the reinforcing insulator 4 from the conductor pull-out rod 6.
A lower case 9 equipped with a flange 8 is connected to the lower part of the case by bolts, and the lower end of the lower case 9 formed to have a small diameter is fixed to the sheath 2 by means of a leadwork 10, and the package is sealed. The chamber 11 thus formed is filled with the same insulating oil or gas as the inside of the cable 1.

A case 12 is placed over the outer periphery of the mantle 7, with the lower end fixed on the lower case 9, and insulating oil or gas from the equipment is poured into the chamber 13 formed by the inner surface of the case 12 and the outer surface of the mantle 7. The upper end of the conductor pull-out rod 6, which has been filled and passed through the upper part of the sleeve 7, is connected to the equipment side by a connecting rod 14.

By the way, the conductor pull-out rod 6 inside and outside the cannula 7
Air-tightness and oil-tightness in the penetrating part are achieved by an O-ring 16 press-fitted into a groove 15 provided in the part of the conductor pull-out rod 6 into which the sleeve 7 fits, and a tightening bolt 17 fixed to the upper surface of the sleeve 7. It is held by an O-ring 19 provided between the metal fitting 18 and the sleeve 7.

In the termination box as described above, when the oil pressure on the cable side is greater than the gas pressure inside the case 12,
If airtightness is compromised, insulating oil from the cable side will seep into the case, reducing the insulation performance between the case and the upper metal fitting of the termination box, causing electrical breakdown, so leakage is definitely prevented. must be prevented.

However, the seal structure in which an O-ring is provided at the fitting part of the conductor pull-out rod and the sleeve can be damaged due to deterioration of the O-ring, flaws on the contact surface of the O-ring, or poor surface finish.
There is a problem in that it causes leakage and the reliability of the sealing function is extremely low.

Furthermore, a seal structure as shown in Fig. 2 has been proposed for OF cables.

This seal structure includes a case 21 and O-rings 22, 23 on the sleeve 7 of the seal structure shown in FIG.
Add and install the high viscosity oil 24 inside the case 21.
It has a structure in which it is filled with a space 25 left at the top.

However, in the case of an OF cable, the O
If the oil tightness of rings 16 and 19 is damaged,
The insulating oil on the cable side, which has a low viscosity, flows into the case 21, and after flowing in, it mixes with the high viscosity oil, making it difficult to flow back, increasing the amount of oil in the case 21, and increasing the oil temperature. In some cases, the case 21 may be damaged due to the increase in internal pressure.

In addition, since the space 25 inside the case 21 is normally filled with SF ₆ gas at atmospheric pressure, high viscosity oil is also filled with SF ₆ gas.
This means that it is saturated with gas, which is not desirable when considering the possibility of SF ₆ gas entering the cable side.

Furthermore, since it is necessary to add the case 21 and O-rings 22 and 23, there is a problem that the structure becomes complicated, takes a long time to assemble, and increases material and assembly costs.

This idea was made to solve various problems with the conventional seal structure mentioned above.
The reliability of the seal part is greatly improved with a simple structure, and even if insulating oil from the cable side leaks into the case side, it will not infiltrate into the case, and the seal structure uses low material and assembly costs. The purpose is to provide.

Hereinafter, one embodiment of this invention is shown in the third figure of the attached drawing.
This will be explained based on FIG.

As a first example, as shown in FIG.
An epoxy resin unit 32 is integrally formed on the outer periphery of the cable by molding, and the sealing effect of the integral molding seals the insulating oil on the cable side without the conventional O-ring 16 shown in FIG.

Although not shown in the drawings, the center conductor 31 has a lower end connected to a cable conductor by crimping or the like, and an upper end connected to an equipment bus bar via a high voltage shield.

As a second example, an O-ring 16 may be used to seal between the center conductor 31 and the epoxy resin unit 32 as shown in FIG.

A cylindrical wall 33 surrounding the center conductor 31 is provided at the upper end of the resin unit 32, and an annular recess 34 that opens at the upper end on the equipment side is formed in the inner peripheral surface of the cylindrical wall 33.

There is grease or high viscosity oil 3 in the recess 34.
5 is injected, and an O-ring 36 is press-fitted into the upper part of this recess 34 between the center conductor 31 and the cylindrical wall 33 so as to be deformed in the radial direction, so as to prevent the grease or high-viscosity oil 35 from flowing out. It is sealed.

A cavity 37 is provided inside the central conductor 31, and a communication hole 38 between the cavity 37 and the annular recess 34 is formed in a portion located within the recess 34 above the regular mounting position of the O-ring 36. .

The seal structure of this invention has the above-mentioned configuration, and when assembling the cable termination box, grease or high viscosity oil 35 is injected into the recess 34 formed by the resin unit 32, and an O-ring is placed at a steady position in the middle. 36, and seal the insulating oil on the cable system side and the insulating gas in the case with the O-ring 36 and grease or high viscosity oil 35.
Prevents insulating oil from the cable system from flowing into the case.

By the way, if the insulating oil on the cable side were to leak into the equipment case along the fitting part between the center conductor 31 and the resin unit 32, the oil pressure in the recess 34 sealed with the O-ring 36 would rise, and the O The ring 36 is pushed up and moved upward.

O-ring 3 pushed up due to continued leakage of insulating oil
6 passes through the communication hole 38 and rises to the position indicated by the dashed line in FIG. 3, the recess 34 and cavity 37 communicate with each other through the communication hole 38.

Therefore, the insulating oil leaked into the recess 34 flows into the cavity 37 through the communication hole 38, and the insulating oil leaks into the cavity 34.
7 to prevent insulating oil from leaking into the equipment case.

Even if the cable insulating oil were to leak to the case side, the leakage speed would be at the level of seepage, and the volume of the cavity 37 would be enough to deal with the problem for a long period of time.

As described above, according to this invention, an annular recess is provided on the inner periphery of the part where the center conductor passes through at the upper end of the resin unit, and grease or high-viscosity oil is injected into this recess and an O-ring is press-fitted. Therefore, the seal at the center conductor penetration part only needs to be injected with grease or high viscosity oil and press-fitted with an O-ring, which simplifies the structure and facilitates assembly work, making it possible to reduce costs.

Furthermore, since sealing is performed using grease or high viscosity oil and an O-ring, leakage of insulating oil from the cable side to the equipment side is reduced, greatly improving the reliability of the sealing effect.

In addition, a hollow part is provided inside the center conductor, and a communication hole between the annular recess and the hollow part is provided above the regular mounting position on the peripheral wall of this hollow part, so even if the insulating oil on the cable side leaks, the By pushing up the ring, leakage can be contained within the cavity, making it possible to more reliably prevent the cable insulating oil from infiltrating the equipment side insulating gas.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view showing a conventional seal structure, Fig. 2 is a longitudinal sectional view showing another example of the same as above, and Fig. 3 is a partially cutaway front view showing a conventional seal structure.
The figure is a longitudinal sectional view showing a first example of the seal structure of this invention, and FIG. 4 is a longitudinal sectional view showing a second example of the seal structure of this invention. 1... Cable, 5... Cable conductor, 16...
... O-ring, 31 ... Center conductor, 32 ... Resin unit, 33 ... Cylindrical wall, 34 ... Recess, 35 ...
...Grease or high viscosity oil, 36...O ring,
37...Cavity portion, 38...Communication hole.

Claims (1)

[Scope of utility model registration request] The outer periphery of the center conductor whose lower end can be connected to the cable conductor in a cable terminal in which the connecting part between the cable conductor and the equipment side is surrounded by a case for storing fluid, and the case and cable system side are separated. Either the resin unit is integrally formed with a mold, or the center conductor penetration part is sealed with an O-ring, and at the upper end of the resin unit, an annular recess that opens on the equipment side is provided on the inner periphery of the part through which the center conductor passes. Seal oil is injected into the center conductor and an O-ring is press-fitted into the upper end position to form a cavity in the center conductor. A sealing structure for a conductor penetration part in a cable terminal, characterized by having a communication hole with an annular recess.