JPH0122359Y2 - - Google Patents

Description

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

As shown in FIG. 1, in the conventional termination box, the sheath 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 leadwork 10, and the package is sealed in an airtight package. 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 tube 7.

In the termination box as described above, if the insulating oil or gas in the case 12 gets mixed into the cable 1 side,
The occurrence of leakage must be reliably prevented since it threatens the insulation performance of the cable and causes electrical breakdown of the cable.

However, the seal structure in which an O-ring is provided at the fitting part of the conductor pull-out rod and the sleeve tube may cause leakage if the O-ring deteriorates or the O-ring contact surface is flawed or has a poor surface finish, and the sealing function may be impaired. The problem is that reliability is extremely low.

In order to prevent the insulating fluid on the case side from entering the cable side, it is possible to make the pressure of the insulating fluid in the case lower than that on the cable side.
There is an inconvenience that the insulating fluid pressure on the cable side must be increased.

Furthermore, when the power cable is an OF cable, a seal structure as shown in FIG. 2 is adopted.

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, if the oil-tightness of the O-rings 16 and 19 of the sleeve 7 is impaired, the insulating oil on the cable side, which has a lower viscosity, will leak into the case 2.
After flowing into the case 21, it mixes with high viscosity oil, making it difficult to flow back, and when the amount of oil inside the case 21 increases and the oil temperature rises, the case 21 is damaged due to the increase in internal pressure. There is a risk of

In addition, since the space 25 inside the case 21 is normally filled with SF ₆ gas at atmospheric pressure, high viscosity oil can also be used.
This means that it is saturated with SF ₆ 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 devised to solve the various problems encountered with the conventional seal structure mentioned above, and it has a simple structure that greatly improves the reliability of the seal part.
The purpose is to provide a seal structure with low material and assembly costs.

An embodiment of this invention will be described below with reference to FIGS. 3 and 4 of the accompanying drawings.

Figure 3 shows the first example of this invention,
A groove 15 is provided around the outer periphery of the portion of the conductor pull-out rod 6 that fits into the sleeve 7, and an O-ring 16 is installed in the groove 15.

A cylindrical wall 31 surrounding the conductor pull-out rod 6 is provided at the upper end of the sleeve 7 formed using epoxy resin, and an annular recess 32 that opens at the upper end on the equipment side is provided on the inner peripheral surface of the cylindrical wall 31. is formed.

There is grease or high viscosity oil 3 inside the recess 32.
3 is injected, and an O-ring 34 is press-fitted into the upper part of this recess 32 between the conductor pull-out rod 6 and the cylindrical wall 31 so as to be deformed in the radial direction, so as to prevent the grease or high-viscosity oil 33 from flowing out. It is sealed.

Figure 4 shows a second example of this invention,
A center conductor 41 is used as the conductor, and an epoxy resin unit 42 similar to the sleeve 7 in FIG. 1 is integrally formed around the outer periphery of the center conductor 41 by molding. The O-ring 16 in the example is omitted to seal insulating oil and gas on the cable side.

Although the center conductor 41 is not shown, its lower end is connected to the cable conductor by crimping or the like, and
The upper end is connected to the equipment side bus bar via a high voltage shield.

Similarly to the first example, a cylindrical wall 43 is provided at the upper end of the resin unit 42, and grease or high viscosity oil 33 is injected into the recess 32 formed on the inner periphery and an O-ring 34 is press-fitted. There is.

The seal structure of this invention has the above-mentioned configuration, and when assembling the cable termination box, grease or high viscosity oil 33 is injected into the recess 32 formed by the sleeve 7 or the resin unit 42, and the upper end is filled with O2.
All you have to do is press fit the ring 34, and the O-ring 34 and grease or high viscosity oil 33 seal the insulating fluid between the cable system side and the case, preventing insulating gas or oil from entering the cable system from the equipment side. To prevent.

As described above, according to this invention, an annular recess is provided on the inner periphery of the part where the conductor passes through at the upper end of the sleeve, and grease 2 or high viscosity oil is injected into this recess and an O-ring is press-fitted. Therefore, the seal at the 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, the intrusion of insulating gas or insulating oil from the equipment side into the cable system is reduced, greatly improving the reliability of the sealing effect.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing a first example of a conventional seal structure, Fig. 2 is a vertical sectional view showing a second example of the same, and Fig. 3 is a first example showing a seal structure of this invention. FIG. 4 is a vertical cross-sectional view of the second example. 5...Cable conductor, 6...Conductor pull-out rod, 7...
...Mantle, 12...Case, 16...O-ring, 3
1, 43... Cylindrical wall, 32... Recess, 33... Grease or high viscosity oil, 34... O ring, 41
...Center conductor, 42...Resin unit.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a cable terminal in which the connection between the cable conductor and the equipment side is surrounded by a case for containing fluid, and the case and the cable system side are separated by a jacket, the upper end of the jacket An annular recess that opens on the equipment side is provided on the inner periphery of the part where the conductor penetrates, sealing oil is injected into the recess, and O is placed at the upper end.
A sealing structure for a conductor penetration part at a cable terminal, characterized by a press-fitted ring. (2) The conductor in the cable terminal according to claim 1 of the utility model registration claim, characterized in that a center conductor is used as the conductor, and the sleeve is formed of a resin unit integrally molded with the center conductor. Seal structure of the penetration part.