JP3638240B2 - Prefabricated connection for plastic cable and its assembly method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a prefabricated connecting portion such as a CV cable (cross-linked polyethylene insulated power cable) and an assembling method thereof.
[0002]
[Prior art]
Assembling of the prefabricated connection portion such as a CV cable is performed by inserting a pre-molded insulator formed in advance on the end of the cable insulator. And since the diameter of the inner cylinder part of the pre-mold insulator is formed smaller than the outer diameter of the cable insulator, silicone oil or the like is applied to the outer surface of the cable insulator and the inner peripheral surface of the pre-mold insulator when inserting. Lubricating oil was applied and inserted.
[0003]
[Problems to be solved by the invention]
Since the conventional pre-mold insulator insertion method described above is carried out in the atmosphere, even if a sufficiently degassed silicone oil is applied, a void is involved when the silicone oil is applied, and a void is inserted when the pre-mold insulator is inserted. These voids may remain at the interface between the outer peripheral surface of the cable insulator and the inner surface of the pre-mold insulator. The 66-77kV class pre-molded insulator has a relatively short upper interface length, and the voids involved can be released by pushing the spring from the rear and applying pressure when assembling the connection part. In the pre-molded insulator, the interface length is long, and it is difficult to sufficiently release the void.
[0004]
[Means for Solving the Problems]
The present invention provides a method for assembling a prefabricated connecting portion that solves the above-described problems, prevents the occurrence of entrainment voids, and has stable insulation performance. The first feature of the present invention is the outer periphery of a cable insulator. In the prefabricated connecting portion for a plastic cable having a pre-molded insulator, the pre-molded insulator has a taper whose diameter is increased at an angle of 0.2 ° or more from the central part of the inner cylinder part toward both sides.
[0005]
In addition, the method for assembling the connecting portion is such that the space of the inner cylinder portion of the premold insulator is sealed, and the space portion is evacuated and then filled with insulating oil and pressurized. It is inserted on a cable insulator.
[0006]
The second feature is that, in the prefabricated connecting portion for a plastic cable having a premolded insulator on the outer periphery of the cable insulator, the cable insulator is moved from the vicinity of the cable semiconductive layer toward the end of the cable insulator by 0.5 deg. The taper shape is reduced in diameter at the above angle.
[0007]
In addition, the method for assembling the connection part is to attach a half-cracked cover on the outer periphery of the pre-molded insulator to form a sealed structure. The premolded insulator is inserted on the cable insulator in a state.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The first feature of the present invention will be described with reference to FIG. FIG. 1 is a longitudinal sectional view showing a state in which a pre-mold insulator is inserted into a predetermined position.
In this specific example, tapers 21 and 22 having diameters increased by an angle of 0.2 deg or more are formed from the central portion A of the inner cylindrical portion of the premolded insulator 4 toward both sides. Thereby, when the premold insulator 4 is inserted on the cable insulator 1, the surface pressure becomes maximum at the central portion A of the inner cylinder portion of the premold insulator 1, and this surface pressure is the end portion of the premold insulator 1. As the distance increases, the voids present at the interface between the inner peripheral surface of the pre-molded insulator 1 and the outer surface of the cable insulator 1 can be released to both sides. In this case, it goes without saying that the present invention can be used in combination with the specific example shown in FIG. 1 or FIG.
[0009]
The second feature of the present invention will be described with reference to FIG. FIG. 2 is a longitudinal sectional view showing a state in which the pre-mold insulator is inserted into a predetermined position. In the drawing, the same reference numerals as those in FIG. 1 represent the same parts.
[0010]
In this specific example, the outer diameter of the cable insulator 1 is formed in a taper 31 shape whose diameter is reduced by an angle of 0.5 deg or more from the vicinity of the outer semiconductive layer 2 of the cable toward the end of the cable insulator. Thereby, when the premold insulator 4 is inserted on the cable insulator 1, the surface pressure decreases toward the end of the cable insulator 1, and the inner peripheral surface of the premold insulator 4 and the outer surface of the cable insulator 1 are reduced. It becomes possible to release voids present at the interface toward the end of the cable insulator 1.
[0011]
【The invention's effect】
As described above, according to the prefabricated connecting part for plastic cable and the assembling method of the present invention, no voids that cause a decrease in the insulating performance of the connecting part are involved, so that the prefabricated connection having stable insulating performance is obtained. This is particularly effective when used to form a prefabricated connection for 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 connection portion showing a second feature of the present invention.
[Explanation of symbols]
1 Cable insulator 2 Cable outer semiconductive layer 3 Cable conductor 4 Pre-molded insulator
21, 22 Premolded insulation body cylinder taper
31 Cable insulation taper

Claims (4)

In the prefabricated connection part for plastic cables having a pre-molded insulator on the outer periphery of the cable insulator,
The pre-mold insulator has an angle of 0.2 deg or more from the center to both sides so that the surface pressure becomes maximum at the center of the inner cylinder and the surface pressure decreases toward the end of the pre-mold insulator. A prefabricated joint for plastic cables, characterized by having a taper that is expanded in diameter. The surface pressure is maximized at the central portion of the inner cylinder portion of the pre-mold insulator, and the surface pressure decreases toward the ends of the pre-mold insulator so that the surface pressure decreases from the center portion to both sides at an angle of 0.2 deg or more. A method for assembling a prefabricated connecting portion for a plastic cable, comprising inserting a pre-molded insulator having a tapered taper on the cable insulator. In the prefabricated connection part for plastic cables having a pre-molded insulator on the outer periphery of the cable insulator,
The cable insulator has a tapered shape whose diameter is reduced at an angle of 0.5 deg or more from the vicinity of the cable semiconductive layer toward the end of the cable insulator so that the surface pressure decreases toward the end. A prefabricated connection for plastic cables. The cable insulation is formed in a tapered shape with a diameter reduced from the vicinity of the cable semiconductive layer toward the end of the cable insulator at an angle of 0.5 deg or more so that the surface pressure decreases toward the end. A method of assembling a prefabricated connecting portion for a plastic cable, comprising inserting a pre-molded insulator on the body.

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