JPH038032Y2 - - Google Patents

Description

[Detailed description of the invention] (1) Industrial application field The present invention relates to a connection box for a corrugated aluminum power receiving cable.

(2) Prior art Figure 6 shows a conventional junction box for power cables with a corrugated aluminum sheath (aluminum corrugated sheath).
This figure shows an example of an intermediate junction box for a single-core OF cable, where 1 is the cable core, 2 is the reinforcing insulator for the conductor connection, 3 is the corrugated aluminum sheath, and 4 is the cable core.
1 is a temporary oil stopper with one end attached to the outer circumference of the terminal of the aluminum sheath and the other end to the cable core, 5 is the outer box, 6 is the insulating oil, 7 is the lead fitting for sealing the end of the outer box, 8 is the vacuum oil lubrication device It is a connector.

The temporary oil stop device 4 is provided to prevent the insulating oil inside the cable from flowing out from the gap between the cable core and the aluminum sheath during conductor connection work, and there are no holes in the surrounding wall. The communication between the oil passage in the conductor and the space directly under the aluminum cover is through an oil flow that passes through the cable insulation layer in the radial direction.

(3) Problems to be solved by the invention However, in the cable connection section equipped with the above-mentioned temporary oil stopper, the insulating oil existing in the space directly under the aluminum is contained, although incompletely.
Several problems have arisen in maintaining the insulation performance of cables.

That is, in this type of cable, the lead work part 7
The heat generated during construction tends to deteriorate the insulating oil directly under the aluminum near the leadwork part. Therefore, it is desirable to diagnose the deterioration of the oil in that part. This requirement cannot be met because the oil cannot be extracted externally, and air may enter the space directly under the aluminum cover when the temporary oil stopper is installed. Problems have also arisen in that it is difficult to remove the air when an incident occurs.

Therefore, it has been considered to attach a valve to the temporary oil stop device and connect this valve to the oil passage connector installed outside the junction box using an oil pipe, but in adopting this structure, The problem is how to absorb positional deviations between the valve and connector due to processing errors and the like.

In other words, as shown in Japanese Patent Publication No. 43-2506, in a structure in which the oil passage connector and the valve are simply connected using a hollow rod, the connection box may be damaged due to misalignment between the two due to processing and assembly errors. assembly becomes impossible.

Of course, it is possible to apply the technique shown in FIG. 8 of Japanese Patent Application Laid-Open No. 57-80215 to this structure to provide flexibility in adjusting the position of the valve fixed in the cable axial direction with respect to the temporary oil stop device. However, even with this method, it is not possible to deal with positional deviations in the circumferential direction of the cable. Also, since the adjustment requires nut operation and the valve used is not a stop valve,
It is unavoidable that oil will leak from the cable between pulling the junction box over the connection and attaching the hollow rod (stop valves cannot be used because they lead oil to the outside through the hollow rod).

As shown in Figure 4 of JP-A No. 57-80215,
Although there is a method of connecting the temporary oil stop device and the oil passage connector with a flexible spiral tube, this leads to deterioration of assembly efficiency, increase in processing cost, and complication of the structure. Also,
Since the temporary oil stop device does not have a valve (it cannot be installed because it would be misaligned with the oil line connector), to prevent oil leakage during assembly, the pipe should be closed with a plug until the spiral pipe is connected. I have no choice but to adopt a complicated method.

(4) Means for solving the problems This invention solves the above problems with the aim of maintaining cable performance, improving assembly ease, and preventing oil leakage during assembly.The junction box has the following configuration. It has characteristics in that.

Its features include a temporary oil stopper that is fixed to the end of the aluminum sheath, or a guide pipe that is integrally formed with an internal passage connected to the temporary oil stopper that is attached to the end of the aluminum sheath. A connecting tube that liquid-tightly surrounds the communicating hole is attached so as to be rotatable and slidable in the longitudinal direction, and this connecting tube is provided with a fitting hole in the cable radial direction that communicates with the communicating hole. A valve body is provided to open and close the oil passage between the communication hole and the fitting hole by operating the operation part from the outside, and on the other hand, one end of the oil passage is closed with a blind stopper in the outer box and exposed to the outside. By installing an oil path connector and inserting the other end of the connector into the fitting hole of the connecting pipe in a liquid-tight manner, the space directly under the aluminum cover is led out to the outside of the outer box.

(5) Embodiment An embodiment of the junction box according to the present invention will be explained based on the attached FIGS. 1 to 3.

Figures 1 and 2 show a junction box according to the first embodiment, and as shown in the figures, one end is tightened and fixed to the outer periphery of a cable core 1, and the other end is attached to a corrugated aluminum sheath.
The temporary oil stopper 10 is installed by sealing the outer peripheral part of the end (9 is the seal part), and is formed slightly longer than the conventional one, and has a communication hole 10a in the middle of the peripheral wall away from the cable core. is provided.

In addition, in the portion where the communication hole is provided, the temporary oil stop device 10 has a first fitting hole 11a parallel to the cable axis.
The connecting pipe 11 provided with the second fitting hole 11b communicating with the space directly under the aluminum through the communicating hole 10a at right angles to It is fitted externally so as to be located between the O-rings 12 (one not shown) attached to both ends, and the second fitting hole 1 of this connecting pipe is further fitted.
The base end of 1b has an operating part 13a such as an operating hole or a square shaft in place of the hole on the upper surface, and a valve seat formed on the inner surface of the hole 11b that moves in the cable radial direction when operated from the outside. A valve body 13 that opens and closes an oil passage between the oil passage and the oil passage 11c is screwed together.

On the other hand, a connector 14 having an oil passage 14a is attached to the outer box 5 that houses the conductor connection portion. In this connector, the other end is inserted from the outside of the outer box into the hole 11b of the connecting pipe 11 with the O-ring 15 inserted therebetween, and then the intermediate flange 14b is inserted into the connector seat 16 provided in the outer box. It has a cap nut 18 at one end protruding from the outside of the outer box, and a blind plug 19 that closes one end opening of the oil passage 14a by tightening the nut.

Connecting pipe 11 with the temporary oil stop device and connector 14
The reason for the connection is that when temporary oil stoppers are installed on both sides of the conductor connection, the distance between the pair of temporary oil stoppers may change due to assembly errors, and the distance between the connector seats 16 may change due to variations in manufacturing tolerances. This is to absorb the positional shift that occurs between the temporary oil stopper and the connector connected to it due to such reasons. Also, the reason why the valve body is built into the connecting pipe 11 is that when the device 10 is installed,
By keeping this valve body closed, the purpose is to prevent the insulating oil existing in the space directly under the aluminum from leaking out. After the connection box configured as described above is assembled, the blind plug 19 of the connector is removed. Then, by inserting a rod wrench or the like into the oil passage 14a from the outside of the connector and opening the valve body 13, the insulating oil and accumulated air directly under the aluminum cover, which were previously sealed, can be taken out, or the insulating oil can be removed. Some parts can be replaced.

As shown in FIG. 3, the connecting pipe 11 has a closed internal passage at one end that communicates with the space directly under the aluminum cover, and a bent tip that is parallel to the cable axis. The guide tube 10b may be integrally formed and fitted around the outer periphery of a communication hole 10a provided in the middle of the tube. In this case, the connecting tube can be made smaller. However, the structure of the first embodiment is more practical because the distance from the center of the cable to the connector 14 can be shortened, so the diameter of the outer box does not need to be increased.

Further, as shown in FIG. 4, a hole 14c communicating with the inner chamber of the outer box 5 is provided in the body of the connector 14, and a hole 14c of the connector is provided in the middle of the outer surface of the connector.
Hole 20a whose position in the cable radial direction matches that of 4c
A pipe 20 having an operating part 20b such as a notch at its upper end is brought into close contact with the inner surface of the oil passage 14a, and the outer periphery of the pipe at the upper and lower positions of the hole is sealed with an O-ring 21. If it is inserted so that it can be rotated in a fixed position, it becomes possible to interrupt the communication between the lower part of the aluminum cover and the inner chamber of the outer box 5.

That is, by inserting a tool into the opening of the connector and rotating the pipe 20, the hole 14c is opened as shown in FIG.
When closed, it exhibits the same function as the junction box shown in FIG. 1 or 3. On the other hand, when the pipe 20 is rotated to connect the holes 14c and 20a as shown in FIG. Since it is connected to the other aluminum sheathed lower part through the inner chamber of the outer box, an oil passage in the axial direction of the cable is formed. Compared to the case where is connected to the oil passage in the conductor,
Fluctuations in oil pressure directly below the aluminum are reduced, which is advantageous in terms of oil supply design.

In addition, when the holes 14c and 20a are in communication, the valve 1
3, the connector 14 can also be used as a vacuum lubrication connector for the outer box.

As shown in Fig. 2, in the intermediate junction box, the above-mentioned means for connecting the space directly under the aluminum cover to the outside are provided on the left and right sides of the conductor connection part, but in the present invention, one temporary unit is installed inside the outer box. It is also applied to terminal junction boxes, branch junction boxes, etc. that are equipped with oil stop devices.

(6) Effects As mentioned above, the connection box of the present invention, in which the temporary oil stop device attached to the end of the aluminum sheath is connected to the connector on the outer box via the connecting pipe with a built-in valve body, can save space directly under the aluminum sheath. Since the outer box can be opened and closed from the outside, the advantages and effects listed below can be obtained.

(1) When performing lead work on the outer box, it is possible to prevent deterioration of the cable due to heating by applying an oil flow to the insulating oil directly below the lead work, and also to drain the insulating oil, which serves as a cooling medium, to the outside. Since the insulating oil that has undergone heating history can be removed, it is possible to construct electrically superior cable lines.

(2) Even if air gets into the space directly under the aluminum sheathing, the air can be removed by opening the connector and creating an oil flow inside the cable, making it easier to deal with such unexpected situations.

(3) It is possible to sample the insulating oil directly under the aluminum and perform deterioration diagnosis using gas analysis, etc., and it is also possible to partially replace deteriorated oil.

(4) Since the connecting pipe has a built-in valve body, it is possible to prevent the insulating oil from flowing out when installing the temporary oil stop device, and this connecting pipe can be slid in the cable axis direction and is rotatable. , structure complexity,
The positions of the oil path connector and the valve in the connection pipe can be very easily matched without increasing labor and the like, and there is no problem in assembling the connection box.

(5) If the body of the connector has a hole that can be opened and closed and communicates with the inner chamber of the outer box, the lower part of the aluminum sheathing of the connecting cable can be communicated through the inner chamber of the outer box, making it easier to lubricate. This is advantageous in terms of design, and the connector can also be used as a vacuum lubrication connector for the outer box.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main parts of one embodiment of the junction box according to the present invention, FIG. 2 is a diagram showing the whole of the junction box, and FIG. 3 is a sectional view showing the main parts of another embodiment. figure,
FIGS. 4 and 5 are sectional views showing essential parts of still another embodiment, and FIG. 6 is a sectional view of a conventional junction box. 1...Cable core, 2...Reinforcement insulator, 3...
... Corrugated aluminum cover, 5 ... Outer box, 10 ... Temporary oil stop device, 10a ... Communication hole, 10b ... Guide pipe, 1
1... Connection pipe, 12, 15, 17, 21... O-ring, 13... Valve body, 14... Connector, 16...
... Connector seat, 18 ... Cap nut, 19 ... Blind plug, 20 ... Pipe.

Claims (1)

[Scope of claim for utility model registration] (1) At the terminal part of the corrugated aluminum cover stored in the outer box,
In a power cable junction box equipped with a temporary oil stopper that closes the opening of the space between the aluminum sheath and the cable core, a guide pipe integrally formed with the temporary oil stopper or an internal passage communicating with the device is used. A connection pipe that liquid-tightly surrounds the external communication hole provided in the temporary oil stop device or the guide tube is attached to the outer periphery so as to be rotatable and slidable in the longitudinal direction. A fitting hole is provided in the fitting hole, and a valve body is provided in the fitting hole to open and close the oil passage between the communication hole and the fitting hole by operating the operation part on the top surface from the outside. The corrugated aluminum sheathing is characterized in that one end of the oil passage is closed with a blind stopper and an oil passage connector is attached facing the outside, and the other end of this connector is inserted into the fitting hole of the connection pipe in a liquid-tight manner. Junction box for power cables. (2) A hole communicating with the inner chamber of the outer box is provided in the body of the connector, and a hole is provided in the connector in the middle of the outer circumferential surface so that the communication hole in the connector body matches the position in the radial direction of the cable. The pipes each having an operating part at the upper end are inserted in close contact with the inner surface of the oil passage of the connector, and are rotatably inserted in a fixed position by sealing the outer circumference of the pipe liquid-tightly at the upper and lower positions of the pipe hole. A connection box for a corrugated aluminum power receiving cable according to claim 1 of the utility model registration.