JP2921348B2 - Connection for plastic insulated power cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a connection for a plastic insulated power cable.

[0002]

2. Description of the Related Art FIGS. 2 and 3 show a typical structure of a connection portion for a plastic insulated power cable, in which all ends (outer sheath, outer semiconductive layer) are formed at a terminal of a power cable 1 to be connected. , Plastic insulator), and the conductor terminal 11 exposed from the end of the stripped plastic insulator 12 is inserted into the conductive sleeve 2 and the conductor connection portion 2a is formed by compressing the sleeve. I was Reference numeral 4 denotes a cylindrical insulating unit formed by casting a synthetic resin such as an epoxy resin into a predetermined mold and embedding the shield electrode 3 so as to partially expose the inner peripheral surface side. The insulating unit 4 is inserted on the power cable on one side before conducting such a conductor connection, and is relocated to the conductor connection portion after the conductor connection, and the shield electrode 3 is electrically connected to the central jetty of the sleeve 2. It is arranged so as to extend outside of the plastic insulator 12 via the conductor connecting portion 2a of the sleeve in a connected state. Reference numeral 6 denotes a stress cone made of an elastic material such as rubber. The stress cone 6 is interposed between the plastic insulator 12 and the insulating unit 4 and is elastically pressed by the spring unit 7 and the pressing tool 8 from the rear, thereby forming the stress cone 6. The outer peripheral surface of the plastic insulator 12 and the inner peripheral taper surface of the insulating unit 4 are brought into close contact with each other while applying a surface pressure, thereby ensuring electrical insulation performance.

[0005] Reference numeral 5 denotes a stopper made of an annular insulator, which prevents abnormal insertion of the stress cone 6 by abutting the tip of the stress cone 6 on an appropriate shoulder in the insulating unit 4. Reference numeral 9 denotes a metal joint box, and reference numeral 10 denotes an insulating cylinder.

By the way, in this type of conventional connection portion, as shown in FIG. 5, the conductor connection portion 2a of the sleeve 2 is
At present, it is exposed to the internal space (air) surrounded by the shield electrode 3 of the insulating unit 4 while being naked.

[0005]

According to the conventional connecting portion of this type, the conductor connecting portion 2a of the sleeve, which is exposed in a naked state, is electrically connected to the outside by the shield electrode 3, and the connecting portion 2a of the conductor connecting portion 2a is electrically connected to the outside. The electric field strength at the tip is designed to be sufficiently low, and there is no problem with a normal operating voltage. However, abnormal voltage may be generated during long-term operation, and corona discharge is generated from the exposed end of the conductor connection portion 2a each time, and the insulation performance of the connection portion is repeated due to the repeated accumulation of the corona discharge. It was feared that it would have an adverse effect. Also, it can be said that there is a high possibility that the above-mentioned problem of insulation performance deterioration occurs in a withstand voltage test in which a voltage higher than the operating voltage is applied or a long-term energization verification test. Furthermore, in the unlikely event that the cable itself is injured in any cable section and water enters from there, a so-called water-running phenomenon occurs in which water is transmitted between the conductor wires, and water enters the connection section. In addition, there was a possibility that water running to the conductor in the next cable section might occur. Repairs or cable replacements in that case will be severe in all cable sections where water has penetrated through the connection.

The present invention solves the above-mentioned problems of the prior art, and can suppress the occurrence of corona against an abnormal voltage that can occur during long-term operation. Water can be suppressed , and
Of the dimensions even if the structure is added to satisfy the function of
To enable you to prevent an increase, in which placed the objective to provide a connecting portion for a plastic insulated power cable.

[0007]

According to the present invention, there is provided a connection portion for a plastic insulated power cable provided to achieve the above object, by connecting a conductor terminal exposed at a terminal of a power cable by peeling a step of a plastic insulator. Connected by a conductive sleeve, an insulating unit made of synthetic resin in which a shield electrode is embedded is arranged so as to extend over the conductor connecting portion of the sleeve and over the plastic insulator while electrically communicating with the sleeve. In a plastic insulated power cable connecting portion having a configuration in which a stress cone having elasticity is interposed between the plastic insulator and the insulating unit to apply a surface pressure to both surfaces of the plastic insulator and the insulating unit and make close contact with each other. the outer peripheral surface of the conductor connecting portion of the sleeve is covered with an insulating treatment layer, the plastic
At the end of the insulator, a step is created by reducing the diameter of the insulator itself.
Formed, and the rising surface of this step enters deep on the inner diameter side.
And the inside of this tapered surface
The insulating layer is connected to the outer peripheral surface to be formed .

As described above, since the conductor connection portion of the sleeve facing the internal space (air) of the insulating unit is covered with the insulating treatment layer, the air corona discharge from the tip of the conductor connection portion is suppressed. . In addition, since the insulating layer extends from the conductor connecting portion of the sleeve and is connected to the terminal of the plastic insulator on the cable body side, even if there is water running in the conductor, it is thereby caused by the conductor connecting portion of the sleeve. Water that may occur from a gap between the tip of the plastic insulator and the plastic insulator can be suppressed, and water running into the connection can be eliminated.

The connection of the insulation treatment layer to the terminal of the plastic insulator may be made to the cut end face of the plastic insulator, but in consideration of shrinkback of the plastic insulator which may occur in a long-term use. that keep
It is important to form a step portion on the end of the plastic insulator by reducing the diameter of the plastic insulator itself, and it is practical to connect the insulating layer to the outer peripheral surface of the step portion.
In this case, the rising surface of the step portion may be perpendicular to the cable axis direction, but the dimension in the axial direction is increased by the provision of the step portion. As a structure for reducing the axial dimension, the above-mentioned structure, that is, a structure in which the rising surface of the step portion is formed into a tapered surface that is deeply inserted on the inner diameter side, and the outer peripheral surface is formed inside the tapered surface is provided .
It is . The insulating layer can be formed by winding an insulating tape.

[0010]

FIG . 1 shows an embodiment of a connecting portion for a plastic insulated power cable according to the present invention .
Since the same or similar parts as those in FIG. 3 are denoted by the same or similar reference numerals, reference should also be made to the description relating to FIGS.

In FIG . 1, only the main part of the connection part is shown. In this embodiment, an insulating treatment layer 13 formed by winding an insulating tape around the outer peripheral surface of the conductor connection portion 2a of the sleeve 2 is used.
In addition, one end of the insulation treatment layer 13 in the layer direction extends from the tip of the conductor connection portion 2a so as to fill a valley having the exposed portion of the conductor 11 as a bottom.
2 terminal .

The insulating layer 13 is connected as described above.
However, at the end of the plastic insulator 12, a step is performed by reducing the diameter to a certain length from the end face.
Section 120 "and more specifically,
By cutting the end surface of the edge body 12 into a mortar shape,
Outer surface 121 extending in the direction and its inner end
And a tapered surface 122 'extending to the side.
Then, one end of the insulating layer 13 in the layer direction is
Contact on the outer peripheral surface 121
It is closely attached to the par surface 122 '. Like this
As a result, the insulating layer 13 moves in the axial direction of the step 120 ″.
As it wraps around the outer surface of the specified length, plastic
Wrapped even when insulator 12 shrinks back
Such a communication structure can be maintained within the scope. Also,
Plastic insulation from the outer edge of the paper surface 122 '
Using the original outer surface of the body 12 as it is, the end surface of the step
From the tapered surface 122 'to the tip of the stress cone 6.
To maintain the plastic insulation performance.
To be effective. And also, as described above, insulation treatment
The outer peripheral surface 121 on which the layer 13 is placed is
Provided so as to enter the plastic insulator side from the end face
By providing this kind of stepped part
An increase in the dimension in the vertical direction can be prevented.

[0013]

According to the connecting portion for a plastic insulated power cable of the present invention as described above, the outer peripheral surface of the conductive connecting portion which is the conductive sleeve and faces the inside (air) of the insulating unit is insulated. Since it is covered with the treatment layer, generation of corona can be suppressed even if an abnormal voltage is applied, and stable insulation performance can be maintained even if an abnormal voltage occurs in long-term operation. In addition, since the insulation treatment layer is connected to the terminal of the plastic insulator from the conductor connecting portion of the sleeve, even if there is water running in the conductor, the sleeve is formed from the gap between the tip of the sleeve and the end face of the plastic insulator. Water infiltration into the outer connection portion can be suppressed, and as a result, the cable section that has been injured by cable injuries can be minimized, and the damage in the event of an accident does not increase. And so on. In addition, the present invention
Positive connection structure of edge treatment layer to plastic insulator
A step is provided at the end of the tick insulator, and the axial direction of this step is
Wraps around the outer surface of a predetermined length
In, plastic insulator causing the shoe link back
The communication configuration can be maintained in the range where
It is possible to obtain a reliable structure for stopping. Also, the step
From the outer edge of the tapered surface that enters the cable body
Keep the original outer surface of the plastic insulator
From the tapered surface, which is the terminal surface of the difference part, to the tip of the stress cone
The distance to the edge can be secured and the plastic insulation performance is maintained
Enabled for. And also, as described above,
The outer peripheral surface on which the physical layer is placed
Also provided so as to enter the plastic insulator side
In this case, the length direction where this kind of step is provided
Can be prevented from increasing in size. This has the effect.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a main part of an embodiment of a connecting portion for a plastic insulated power cable according to the present invention, which is cut in half.

FIG. 2 is an explanatory diagram showing a typical example of a connection portion for a plastic insulated power cable in a half cross section.

FIG. 3 is a cross-sectional explanatory view showing a main part of a conventional example of a connecting portion for a plastic insulated power cable, which is cut in half.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power cable 2 Sleeve 2a Conductor connection part 3 Shield electrode 4 Insulation unit 5 Stopper 6 Stress cone 7 Spring unit 8 Pusher 9 Joint box 11 Conductor terminal 12 Plastic insulator 120 "Step 121 Outer surface 122 'Tapered surface

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-93990 (JP, A) JP-A-6-133443 (JP, A) Actually open Showa 50-52494 (JP, U) Actually open 4- 47342 (JP, U) Jiko 3-21172 (JP, Y2) Jiko 50-8228 (JP, Y1) Joko 50-5013 (JP, Y1) Jiko 35-30666 (JP, Y1) J. 36-2666 (JP, Y1) (58) Field surveyed (Int. Cl. ⁶ , DB name) H02G 15/00-15/196

Claims (2)

(57) [Claims] 1. A conductor terminal, which is exposed at a terminal of a power cable by stripping a plastic insulator, is connected by a conductive sleeve, and an insulating unit made of a synthetic resin having a shield electrode embedded therein is electrically mounted on the sleeve. Extending over the conductor connecting portion of the sleeve and over the plastic insulator while being in communication with each other, and an elastic stress cone is interposed between the plastic insulator and the insulating unit to interpose the plastic insulator with the plastic insulator. in plastic insulated power cable connection of the configuration are adhered while providing surface pressure on both sides of the insulating unit, the outer peripheral surface of the conductor connecting portion of the sleeve is covered with an insulating treatment layer, said plastic insulation
Forming a step on the body end by reducing the diameter of itself
Then, the rising surface of this step part penetrates deeply on the inner diameter side
It is a tapered surface like this, formed inside this tapered surface
A connection portion for a plastic insulated power cable , wherein the insulation treatment layer is brought into contact with an outer peripheral surface to be formed. 2. The connection part for a plastic insulated power cable according to claim 1, wherein said insulation treatment layer is formed by winding an insulation tape.