JP2000152455A - Prefabricated joint for plastic cable and its assembling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a prefabricated joint for plastic cables which prevents the generation of voids, and its assembling method. SOLUTION: This prefabricated joint for plastic cables has a premolded insulator on the periphery of a cable insulator. The joint has tapered parts 21, 22, whose diameters have been widened by an angle of 0.2 degree or more from a central part A of the internal cylindrical part of this pre-molded insulator 4 toward its both sides. Consequently, surface pressure becomes maximum at the central part A of the internal cylindrical part of the pre-molded insulator 4, and this surface pressure becomes smaller as it approaches the end part of the pre-molded insulator 4, when the cable insulator 1 is inserted into a pre-molded insulator 4, and it becomes possible to allow voids existing in the interface between the internal peripheral surface of the pre-molded insulator 4 and the external surface of the cable insulator 1 to escape to both sides.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prefabricated connection such as a CV cable (cross-linked polyethylene insulated power cable) and a method of assembling the same.

[0002]

2. Description of the Related Art A prefabricated connecting portion such as a CV cable is assembled by inserting a pre-molded insulator preformed on a terminal of the cable insulator. And since the diameter of the inner cylindrical portion of the pre-molded insulator is formed smaller than the outer diameter of the cable insulator, at the time of insertion, the outer surface of the cable insulator and the inner peripheral surface of the pre-molded insulator have silicone oil or the like. Lubricating oil was applied and inserted.

[0003]

Since the above-described conventional method of inserting a pre-molded insulator is carried out in the air, even if a sufficiently degassed silicone oil is applied, a void is involved in the application of the silicone oil. In addition, when the pre-mold insulator is inserted, voids may be entangled, and these entangled voids may remain at the interface between the outer peripheral surface of the cable insulator and the inner surface of the pre-mold insulator. 66-77kV
Class pre-molded insulator has a relatively short upper surface interface length, and the entangled voids can be released by applying pressure from the back with a spring when assembling the connection part. Insulators have a long interface length and it is difficult to sufficiently escape voids, and these voids have been a factor in lowering the insulation performance of the connection.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, to provide a method of assembling a prefabricated joint having a stable insulating performance and preventing the occurrence of entrapment voids. The feature is that in the prefabricated connection portion for a plastic cable having a pre-mold insulator on the outer periphery of the cable insulator, the pre-mold insulator expands at an angle of 0.2 deg or more from the center portion of the inner cylindrical portion toward both sides. To provide a tapered shape.

In the method of assembling the connecting portion, the space of the inner cylindrical portion of the pre-molded insulator is sealed, and the space is evacuated, filled with an insulating oil and pressurized. The insulator is inserted over the cable insulator.

A second feature is that, in a prefabricated connection portion for a plastic cable having a pre-molded insulator on the outer periphery of the cable insulator, the cable insulator is moved from the vicinity of the cable semiconductive layer to the end of the cable insulator. 0.5deg
This is because the taper shape is reduced in diameter at the above angle.

In the method of assembling the connecting portion, a half-split cover is mounted on the outer periphery of the pre-molded insulator to form a hermetically sealed structure. The pre-molded insulator is inserted on the cable insulator in a state in which is filled.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG.
Will be described. FIG. 1 is a longitudinal sectional view showing a state where a pre-mold insulator is inserted into a predetermined position. In this specific example, tapered portions 21 and 22 whose diameters are increased by an angle of 0.2 deg or more are formed from the central portion A of the inner cylindrical portion of the pre-molded insulator 4 to both sides. As a result, when the pre-mold insulator 4 is inserted onto the cable insulator 1, the surface pressure becomes maximum at the central portion A of the inner cylindrical portion of the pre-mold insulator 1, and this surface pressure is increased at the end of the pre-mold insulator 1. The voids existing at the interface between the inner peripheral surface of the pre-mold insulator 1 and the outer surface of the cable insulator 1 can escape to both sides. In this case, FIG.
Alternatively, it goes without saying that it can be used in combination with the specific example shown in FIG.

The second feature of the present invention will be described with reference to FIG. FIG. 2 is a longitudinal sectional view showing a state where the pre-mold insulator is inserted into a predetermined position. In the drawings, the same reference numerals as those in FIG. 1 represent the same parts.

In this specific example, the outer diameter of the cable insulator 1 is formed in a taper 31 shape whose diameter is reduced from the vicinity of the outer semiconductive layer 2 of the cable toward the end of the cable insulator by 0.5 ° or more. is there. Thereby, when the pre-mold insulator 4 is inserted onto the cable insulator 1, the surface pressure decreases toward the end of the cable insulator 1, and the inner peripheral surface of the pre-mold insulator 4 and the outer surface of the cable insulator 1 are reduced. The void existing at the interface can be released toward the end of the cable insulator 1.

[0011]

As described above, according to the prefabricated connection part for plastic cable and the assembling method of the present invention, a void which is a factor of the insulation performance deterioration of the connection part is not involved. This is particularly effective when used for forming a prefabricated connection portion of an ultra-high pressure plastic cable.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a cable connecting portion showing a first feature of the present invention.

FIG. 2 is a longitudinal sectional view of a cable connecting portion showing a second feature of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cable insulator 2 Cable outer semiconductive layer 3 Cable conductor 4 Pre-mold insulator 21, 22 Pre-mold insulator cylinder taper 31 Cable insulator taper

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Fumio Taho, 1-3-1 Shimaya, Konohana-ku, Osaka-shi Inside the Osaka Works, Sumitomo Electric Industries, Ltd. (72) Koji Kishi, 1-1-1 Shimaya, Konohana-ku, Osaka-shi No. 3 Sumitomo Electric Industries, Ltd., Osaka Works (72) Inventor Masakazu Medieval, 1-3-1, Shimaya, Konohana-ku, Osaka City Sumitomo Electric Industries, Ltd., Osaka Works

Claims (4)

[Claims] 1. A prefabricated connection part for a plastic cable comprising a pre-molded insulator on the outer periphery of a cable insulator, wherein the pre-molded insulator has an angle of 0.2 deg or more from a center part of an inner cylinder part toward both sides. A prefabricated connection for plastic cables, characterized by having an enlarged taper. 2. A pre-molded insulator having a tapered shape whose diameter is increased by 0.2 ° or more toward both sides from the center of the inner cylindrical portion of the pre-molded insulator is inserted into the cable insulator. To assemble prefabricated connections for plastic cables. 3. A prefabricated connection part for a plastic cable comprising a pre-molded insulator on the outer periphery of a cable insulator, wherein the cable insulator is at least 0.5 deg from a vicinity of a cable semiconductive layer toward an end of the cable insulator. A prefabricated connection part for a plastic cable, characterized in that it has a tapered shape whose diameter is reduced at an angle. 4. The cable insulator is formed in a tapered shape having a diameter reduced by 0.5 ° or more from the vicinity of the cable semiconductive layer toward the end of the cable insulator, and a pre-mold insulator is formed on the cable insulator. A method for assembling a prefabricated connection portion for a plastic cable, wherein the connection portion is inserted.