JPS6320084B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to connections for paper insulated power cables, such as OF cables.

The connection part in a conventional OF cable had a structure as shown in Figure 1. That is, the part of the cable insulating paper 2 covering the cable conductor 1 facing the conductor connection part 3 is peeled off, and the end of the cable insulating paper 2 is scraped off in a tapered shape. A reinforcing insulating paper 4 is wrapped around the outer periphery to form a reinforcing insulating layer, and a shielding layer 5 is further provided on the outside of the reinforcing insulating paper 4, and the whole is surrounded by an outer box 6, and the cable metal sheath 7 and the outer box 6 are fitted together. Joining part with lead work 8
It is sealed.

In the connection part of the OF cable as described above, the line connecting the three points A, B, and C in Fig. 1, that is, the interface between the cable insulating paper 2 and the reinforcing insulating paper 4, is the weak point in terms of insulation performance. well known.

Therefore, the electrical stress in the longitudinal direction between point A at the tip of the cable insulating paper 2 and point B at the large diameter end of the tapered part, or between point B and point C at the end of the reinforcing insulating paper 4 can be maintained as required. In the value, those dimensions are calculated.

Therefore, in the connection structure shown in Figure 1, the lengths between points A and B and between points B and C are added in series, and this determines the total length of the connection. Therefore, there was a drawback that the dimensions of the connecting portion became large, especially in the length direction.

Furthermore, in the conventional connection structure, the cable insulating paper 2 near the conductor connection part was peeled off and the end of the insulating paper 2 was scraped off in a tapered shape. I have a problem that requires time.

This invention was made in order to solve the above-mentioned drawbacks and problems, and by making the electrically weak points overlap in the length direction, it is possible to form a reinforcing insulating layer in a small size and in a short time. The purpose is to provide cable connections.

Hereinafter, an embodiment of the present invention will be described based on FIG. 2.

As shown in FIG. 2, the cable insulating paper 12 covering the cable conductor 11 is not completely peeled off, but a part of it is loosened and left, and after connecting the conductor 11 through the connection part 13, A wide insulating paper 14 is wound around the outer periphery to have a trapezoidal cross section with tapered portions 15 on both sides.

Next, the cable insulating paper 12 is cut and rewound to adjust its length so that the end portion is in close contact with the tapered portion 15 of the wide insulating paper 14. Furthermore, wide insulating paper 14
Then, the reinforcing insulating paper 16 is wrapped around the outer periphery of the cable insulating paper 12 on both sides to have a trapezoidal cross-section with tapered portions on both sides, and then the reinforcing insulating paper 16 is wrapped around the outer periphery of the cable insulating paper 12 on both sides.
A shielding layer 17 is provided around the outer periphery of the cable, the entire cable is covered with an outer box 18, and the ends of the cable metal sheath 19 and the outer box 18 are sealed with lead fittings 20.

In the above connection, if the potential of the conductor 11 is E (V), the outer diameter of the reinforcing insulating paper 16 is DA, the outer diameter of the cable insulating paper 12 is DB, and the outer diameter of the conductor 11 is DC, then The voltage at point A located at the tip of the wide insulating paper 14 is of course E, the voltage at point C located at the tip of the reinforced insulating paper 16 is zero, that is, the ground potential, and the voltage at point B, where the tip of the cable insulating paper 12 is located, is E・lnDA. /DB/lnDA/DC.

Therefore, the required distances between points A and B and between points B and C are the same as in the conventional method, respectively: E(1-lnDA/DB/lnDA/DC) = ElnDB/DC/lnDA/DC
It is determined by considering the potential difference between and E・lnDA/DB/lnDA/DC.

In this invention, as shown in the figure, the cable insulating paper 12 is rewound so that the end portions are in close contact with the tapered portions 15 on both sides of the wide insulating paper 14, and a reinforcing insulating paper 16 is further wrapped around the outer periphery of both. Therefore, points A, B and B, C partially or completely overlap in the length direction of the cable.

Therefore, even though the interface between the cable insulating paper 12 and the wide and reinforced insulating papers 14 and 16 has sufficient dimensions in terms of insulation performance, it is shortened in the length direction of the cable by the amount of overlap. .

As described above, according to the present invention, since the interface between the wide and reinforced insulating paper and the cable insulating paper overlaps in the length direction of the cable at the smaller diameter part and the larger diameter part than the outer diameter of the cable insulating paper, The length can be shortened while maintaining the dimensions required for the electrical weak point, and the connecting part can be made smaller in the length direction.

Also, you can loosen a part of the cable insulating paper and leave it behind, cover most of the conductor connection part with wide insulating paper, and then rewind the cable insulating paper along the tapered parts on both sides. This has the effect of improving the efficiency of OF cable connection work by reducing the additional work time required for unwinding the OF cable.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing a conventional OF cable connection section, and FIG. 2 is a vertical cross-sectional view showing a connection section according to the present invention. 11...Conductor, 12...Cable insulation paper, 13
...Conductor connection part, 14...Wide insulating paper, 15...
Tapered portion, 16...Reinforced insulating paper.

Claims (1)

[Claims] 1 Wrap a wide insulating paper around the outer periphery of the conductor connection part in a trapezoidal cross section with tapered parts on both sides, and wrap the cable insulating paper around both sides of the wide insulating paper while unwinding it so that it sticks to the tapered part, Further, reinforcing insulating paper is wrapped around the outer periphery of the wide insulating paper and the cable insulating paper in a trapezoidal cross section with tapered parts on both sides, so that the interface between the wide insulating paper and the cable insulating paper and the interface between the cable insulating paper and the reinforced insulating paper A paper-insulated power cable connection section characterized by overlapped in the length direction of the cable.