JPH0546168B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a structure for wrapping an insulating tape when connecting power cables by a tape wrapping method, and particularly relates to a portion where the insulation coating is removed in a tapered shape to expose the conductor. This invention relates to a structure for wrapping an insulating tape for so-called valley filling, in which the insulating tape is wound to increase the thickness of the insulating coating to about the outer diameter of the insulating coating.

Conventional technology Connecting power cables using the insulating tape method is
Cross-linked polyethylene power cable (CV cable)
It is well known that rubber/plastic power cables such as , 4 in a tapered shape (this is called penciling) and the exposed conductors 5 and 6 are connected by a connecting pipe 7,
After wrapping semiconducting tape 8 around the outer circumferential surfaces of the conductors 5, 6 and connecting pipe 7, insulating tape 10 is wrapped between each pencil ring part until the outer diameter is approximately equal to the outer diameter of the power cables 1, 2. Then, so-called valley filling was performed, and an insulating tape 11 was wrapped around the outer circumference to a thickness necessary for insulation, and stress cones 12 and 13 were formed at both ends of the tape in order to reduce the potential gradient in the longitudinal direction and prevent breakdown. It has a structure.

Such winding of the insulating tape 10 has been done manually, but the length of the insulating tapes 10 and 11 to be wrapped is long, the tension must be maintained uniformly, and there is no need to wrap the insulating tape 10 in the manhole. The work environment was poor in some places, creating a heavy burden on workers. Therefore, recently, a tape winding machine is used to wind the insulating tapes 10 and 11. This involves attaching a tape pad to a taping head that rotates around the power cable on its outer periphery, and attaching the taping head to a movable base that reciprocates in the axial direction of the power cable, allowing the operator to control the running direction of the movable base. The winding direction of the insulating tape is reversed by switching by a switch operation. Conventionally, even when such a tape winding machine is used, the valley between the pencil ring parts of the power cables 1 and 2 is first filled, and after the entire cable has approximately the same outer diameter, the required thickness is added to the outer periphery. An insulating tape 11 is wrapped around the top to form a stress cone.

Problems to be Solved by the Invention The above-mentioned valley filling is performed by wrapping insulating tape in multiple layers so that the insulating tape fills the spaces between each pencil ring part. By reversing the winding direction each time the tape contacts the pencil ring part, the insulating tape is wound in multiple layers to fill in the valleys. That is, folded portions in which the winding direction of the insulating tape is reversed are lined up on the surface of the pencilling portion, and the insulating tape is wound so that the wrapping width becomes wider toward the outer layer to fill in the valleys.

When such valley-filling work is performed using the tape winding machine described above, the operator must operate a switch after visually confirming that the taping head has reached the folded part, but the switch operation is not always performed in a timely manner. , the folded part that reverses the winding direction of the insulating tape often does not line up with the surface of the pencil ring part, as shown in Figure 5.
As a result, the surface of the pencil ring part and the insulation tape 1
Non-uniform voids B are generated between the 0 and 0, which makes it easy to break along the layer. In order to solve this inconvenience, voids can be minimized by manually wrapping the valleys with tape, but this requires a skilled worker and requires a lot of worker effort. The problem arises that the burden increases.

This invention was made against the background of the above-mentioned circumstances, and an object of the present invention is to provide a valley-filling structure for a power cable connection part that is less likely to be damaged along the layer direction and that allows for efficient tape winding. It is something to do.

Means for Solving the Problems In order to achieve the above object, the present invention removes the insulation coating at the ends of a pair of power cables to be connected in a tapered manner to expose the conductors and connect the conductors to each other. Then, wrap insulating tape in multiple layers between the tapered parts of both power cables with the conductor connection part in between, reversing the advancing direction at a predetermined position until the outer diameter is approximately equal to the outer diameter of the power cable. In the valley filling structure at the connection part of a power cable, the point where the winding direction of the insulating tape is reversed is set near the maximum outer diameter of each tapered part of the insulating tape on the inner layer side, and The present invention is characterized in that the tape is set closer to the center of the conductor connection portion.

Effect In the structure of the present invention, the cross-sectional shape formed by the multilayer insulating tape is equal to the cross-sectional shape of the space between the pencil ring portions of each power cable, but for example, the first layer of the multilayer insulating tape The insulating tape for the eyes is continuously wrapped over the entire range from the outer circumferential surface of one pencil ring part, through the outer circumference of the conductor connection part, to the outer circumferential surface of the other pencil ring part, and
The layers are continuously wound over a slightly narrower area than the first layer. Therefore, the folded part that reverses the winding direction of the tape is arranged at the farthest position from the conductor connection part in both the radial and axial directions, and as a result, voids may occur due to positional deviation of the folded part. There is no risk of causing a decrease in electrical strength. In other words, since a slight deviation of the folded portion can be tolerated, conventional mechanical winding can be employed, and work efficiency can be improved.

Examples Next, the valley filling structure of the present invention will be explained based on examples.

The overall configuration of the power cable connection section obtained by adopting this invention is almost the same as the conventional one shown in FIG.
The conductors 5 and 6 are exposed by removing the insulating coatings 3 and 4 in a tapered manner, and are connected by a connecting pipe 7. A semiconducting tape 8 is wrapped around the outer periphery of this conductor connection portion in order to alleviate the potential gradient. In order to minimize the occurrence of voids on the outer circumferential surface of the semiconductive layer and the outer circumferential surfaces of each power cable 1, 2, and to smooth the rising portions of the stress cones 12, 13, approximately 0.3 mm A thin insulating tape 9 is wrapped around the entire area from the outer peripheral surface of one power cable 1 to the outer peripheral surface of the other power cable 2 to a thickness of about 6 mm. In this state, the space between the tapered pencil ring portions of each power cable 1 and 2 is a small diameter valley.
These valleys are filled by wrapping insulating tape 10 in multiple layers until the outer diameter becomes approximately the same as the outer diameter of each power cable 1, 2.

The procedure for winding the insulating tape 10 for filling the valley is as shown in FIG. That is, for example, the insulating tape 10 is started from the outer periphery of the conductor connection part, and is spirally wound in one direction while overlapping about half of the tape width, until the tapered surface of the pencil ring part is wrapped around the maximum outer diameter. After advancing, reverse the winding direction. Then, the winding direction is reversed from the previous one, and the winding passes through the outer circumferential side of the conductor connection part to the vicinity of the maximum outer diameter part of the other pencil ring part, and then the winding direction is reversed to form the second layer. Perform winding. The second layer passes through the outer periphery of the conductor connection part and winds up to the outer periphery of the one pencil ring part, and the winding direction is slightly closer to the center than the folded part where the winding direction of the first layer is reversed. Invert. Thereafter, insulating tape 1 is similarly set, with the folded part for reversing the winding direction being set closer to the center for the outer tape layers.
Perform 0 winding. Therefore, the wrapping state in the pencil ring part is as shown in FIG. 2, and as a result, the insulating tape 10 is wound in a helical manner, shifting by a certain pitch and overlapping, so that voids occur in the pencil ring part. Even so, it is minute and uniform depending on the thickness of the insulating tape 10.

In the valley-filling structure obtained by wrapping the insulating tape 10 in the above-described manner, as is clear from FIG. Since it is located on the outer circumferential side, there is no risk of reducing electrical strength. On the other hand, in the conventional structure, as is clear from FIG. 4, the folded parts are arranged along the pencil ring part,
It becomes easy to break along the layer direction.

After filling the valleys as described above, an insulating tape 11 is further wrapped around the outer periphery, and stress cones 12 and 13 are formed at both ends thereof. This insulating tape 11 can be wound in the same manner as in the conventional method.

Effects of the Invention As is clear from the above description, according to the valley-filling structure of the present invention, the insulating tape is continuously wound around the outer circumference of the tapered surface of the pencil ring of each power cable, and the outer diameter is approximately equal to the outer diameter of the power cable. Since the direction of winding is reversed at certain points, there are no folded sections along the pencil ring section, and the folded sections are arranged on the outer periphery, far away from the conductor connection section. Since irregular and large voids that cause a decrease in strength are no longer present near the conductor, a high-strength connection can be obtained. In addition, since the folded part that reverses the winding direction is located far away from the conductor connection part, there is less electrical influence due to uneven folded parts, and therefore the tape winding machine can reduce the troughs caused by the tape winding machine. It becomes possible to fill in the valleys, and the efficiency of valley filling work can be improved. Furthermore, it has been confirmed that the effects of the present invention can be further improved if applied to a device that can automatically regulate the turning point of a tape winding machine.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the winding procedure for obtaining the valley filling structure of the present invention, Fig. 2 is an explanatory diagram showing the winding state at the pencil ring part according to the present invention, and Fig. 3 is a cross section of the power cable connection part. Pattern diagram,
FIG. 4 is an explanatory diagram showing a conventional winding procedure for an insulating tape, and FIG. 5 is an explanatory diagram showing a wrapping state at a pencil ring part using a conventional valley filling structure. 1, 2...Power cable, 3, 4...Insulation coating,
5, 6...Conductor, 7...Connecting pipe, 10...Insulating tape.

Claims (1)

[Claims] 1. The insulation coating at the ends of a pair of power cables to be connected is removed in a tapered manner to expose the conductors, and the conductors are connected to each other, and both power sources sandwiching the conductor connection portion are connected. In a valley-filling structure at a connection part of a power cable, in which an insulating tape is wound between the tapered portion of the cable, the direction of the winding is reversed at a predetermined position, and the power cable is wound in multiple layers until the outer diameter is approximately equal to the outer diameter. The point at which the winding direction of the insulating tape is reversed is set near the maximum outer diameter portion of each tapered portion for the insulating tape on the inner layer side, and is set closer to the center of the conductor connection portion for the insulating tape on the outer layer side. A valley-filling structure in a power cable connection part characterized by: