JPS5816011B2 - How to connect oil-soaked paper insulated cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of connecting oil-impregnated paper insulated cables, and aims to reduce the size of the connecting portion and save labor.

First, the conventional technology will be described.

The general method (Fig. 1) is to connect the cable conductors 10 with a sleeve 12, create a pencil ring part 14 of the required length, and fill it with a small amount of filler oil on top of it until it has the same diameter as the cable insulator 16. The immersion paper 18 is wrapped, and a wide reinforcing oil immersion paper 20 is wrapped thereon to provide necessary insulation reinforcement, and an external barrier layer 22 is provided thereon.

24 is a cable sheath.

In the connection made in this manner, the interface between the cable insulating paper and the reinforcing insulating paper (A-B-C in FIG. 1) is considered to be the electrically weakest point.

Therefore, it is necessary to make this length sufficiently long, so it is difficult to reduce the size further than the current one.

On the other hand, there is a rewinding method as a method that enables size reduction.

In this method (FIG. 2), before connecting the cable conductor 10,
The cable insulating paper 160 is unwound to a required length, and after the cable conductor 10 is connected, it is unwound and cooked.

In this way, there is no interface as shown in FIG. 1, so the dimensions can be reduced.

However, the problem is that it takes time to unwind and unwind the cable insulating paper 160.

From the above points of view, the present invention aims to (1) use as much of the cable insulating paper 160 of the cable itself as possible in the fabrication of the connection part, like the rewinding method, to minimize electrical weaknesses; (2) The above-mentioned problems are solved by eliminating the need for the time-consuming work of unwinding and unwinding the cable insulating paper 160.

Therefore, in this invention, (1) the end of the cable is frozen before connecting the cable conductor 10, (2) the end face of the cable insulator 16 is then cut,
Make a hole into which the tip of the sleeve 12 can be inserted, (3) insert the tip of the sleeve 12 into the hole, and connect the cable conductor 10 in this state, (4) then unfreeze it, and then, for example, In the same way as in the case of FIG. 1, necessary insulation reinforcement is performed.

Next, examples will be described (FIGS. 3 to 6).

(1) After removing the offset of the cable, first attach the freezing box 26 to the end of the cable (Fig. 3) and freeze it.

After confirming that the insulating oil has frozen, cut the cable and conductor 10.
Interfering with others.

Conventionally, when cutting a cable, there was a concern about oil leaking from the oil passage 30 in the center of the conductor (replacing it with air), but with this method, it is frozen before cutting, so there is no need to worry about that.

(2) Next, use a special cutting machine to make a hole 28 in the end face of the cable insulator 16 in the same shape as the tip of the sleeve 12 (FIG. 4).

Since the end of the cable is frozen, there will be no oil leakage during cutting, making work easier.

Of course, do this for both cables you are trying to connect.

(3) Then, insert the tip of the sleeve 12 into the hole 28, abut the cable conductor 10 inside the sleeve, and crimp the center part (FIG. 5).

Note that 32 indicates a reinforcing steel pipe.

(4) Finish the surface of the sleeve 12 and unfreeze it.

After that, as before, 18 valley-filling oil-impregnated paper, 20 reinforcement oil-impregnated paper
, the necessary insulation reinforcement is provided by the external insulation layer 22 (
Figure 6).

In the above manner, the manufacturing of the connecting portion except for the outer box is completed.

Note that insulation reinforcement after the cable conductor 10 is connected can be performed using any known method.

For example, FIG. 7 shows a case where the epoxy bell mouth 34 is used to further shorten the working time.

36 and 38 are reinforced oil-impregnated papers.

Further, FIG. 8 shows a prefabricated type, in which an epoxy bell mouth 34 is further combined with a sealing ring 40 and an epoxy unit 42.

This invention is applicable not only to OF cables but also to POF cables and other oil-impregnated paper insulated cables.

The effects of this invention will be described below.

(1) Since the tip of the sleeve 12 where electric fields tend to concentrate is wrapped with the cable insulating paper 160, the distance between the end faces of the cable insulating paper and the reinforcing insulating paper can be reduced, and the overall size can be reduced.

(2) Since the cable insulating paper 160 does not need to be unwound or rewound, the working time is shortened.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams of the prior art, and FIGS. 3 to 6 are explanatory diagrams showing the method of one embodiment of the present invention in the order of steps,
FIGS. 7 and 8 are explanatory diagrams of other embodiments of the present invention. 10... Cable conductor, 12... Sleeve, 16...
...Cable insulation, 28...holes.

Claims (1)

[Claims] 1. A method for connecting an oil-immersed paper insulated cable in which necessary insulation reinforcement is performed after connecting cable conductors 10 with sleeves 12, the ends of the cables are frozen before connecting the cable conductors 10, and then A hole 28 is provided on the end surface of the cable insulator 16 into which the tip of the sleeve 12 can fit tightly, and the cable conductor 10 is connected with the tip of the sleeve 12 inserted into the hole 28, and then the freeze is released and the necessary A method for connecting an oil-immersed paper insulated cable characterized by providing insulation reinforcement.