JP2003180027A - Pre-molded rubber insulated cylinder and plastic insulated power cable connection using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conventional pre-molded rubber insulating cylinder formed of an inner semiconductive layer, an insulating layer, and an outer semiconductive layer, having a temperature of 66K.
Above V, the high-voltage shielding electrode has a thickness of 10 mm or more,
This causes a problem that the thickness of the product becomes 30 mm or more. SOLUTION: The internal electrode layer is formed of a sheet-like semiconductive rubber layer having a thin cross section and a high dielectric rubber layer covering at least both ends of the sheet-like semiconductive rubber layer. Both ends are treated with a radius of curvature that is about half the thickness of the sheet, and are floated from the inner surface and placed in the high dielectric rubber layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a premolded rubber insulating tube used for connecting a plastic insulated power cable,
In particular, the present invention relates to a pre-molded rubber insulating tube that can simplify the structure and reduce the cost, and a connecting portion of a plastic insulated power cable equipped with the rubber insulating tube.

[0002]

2. Description of the Related Art Plastic-insulated power cables represented by cross-linked polyethylene insulation are rapidly becoming versatile due to their excellent insulation and easy handling. Along with this, the total number of cable connecting works is increasing, and demands for simplification and shortening of these works are increasing.

In recent years, as a joint which has a short connection time and can be easily connected, a prefabricated type connecting portion using a rubber block formed of an inner semiconductive layer, an insulating layer and an outer semiconductive layer, and further, FIG. The connection part equipped with the one-piece pre-molded rubber insulating tube shown in the figure has been put into practical use.

The connecting portion shown in FIG. 3 covers the connecting portion of the conductor 1 and the cable insulator 2, and the premolded rubber insulating tube 30 mounted on the outer periphery of the cable so as to straddle the outer semiconductive layer 3 of the cable. Although not shown, the insulating cylinder 30
It is provided with a two-part type protective cover for covering and a waterproof processing part formed at both ends thereof. The pre-molded rubber insulating cylinder 30 shown in FIG. 3 generally uses ethylene propylene rubber having high insulation performance and excellent moldability as a base rubber, and has an inner semiconductive layer 31, a reinforcing insulation layer 32 and an outer semiconductive layer. 33 and 33 are integrally molded, and are configured as one component (one piece) as a whole, and simplification is being advanced in terms of connection construction.

[0005]

The above-mentioned internal semiconductive layer,
In a pre-molded rubber insulating cylinder formed of an insulating layer and an external semiconductive layer, at a voltage of 66 KV or higher, a high-voltage shield electrode is used. I was giving it. As a result, there is a problem that the thickness of the product becomes 30 mm or more.

The present invention has been made in view of the above problems. An object of the present invention is to reduce the outer diameter and wall thickness of the entire product by making the internal electrodes of the rubber insulating cylinder extremely thin. , A pre-molded rubber insulating tube that can significantly reduce the manufacturing cost of the product, simplify the work of assembling the cable connecting section by making the rubber insulating tube compact, and reduce the cost required for forming the connecting section, A plastic insulated power cable connection part using the same is provided.

[0007]

In order to achieve the above object, in the present invention, a high dielectric constant (ε
(10 or more) A rubber layer is provided, the electrode sheet thickness is set to 5 mm or less, the electrode tip is treated with a radius of curvature of about half of the sheet thickness, and the electrode sheet is floated from the inner surface in contact with the cable insulator.

The pre-molded rubber insulation tube of the present invention is a pre-molded rubber insulation tube for connecting a plastic insulated power cable, which has an internal electrode layer, a reinforced insulation layer and an external semi-conductive layer formed on the basis of a rubber material. In the above, the internal electrode layer is formed of a sheet-shaped semiconductive rubber layer having a thin cross section and a high dielectric rubber layer covering at least both end portions of the sheet-shaped semiconductive rubber layer. Both tips are treated with a radius of curvature of about half of the sheet thickness, and are floated from the inner surface in contact with the cable insulator and placed in the high dielectric rubber layer.

Further, the thickness of the semiconductive rubber layer of the internal electrode layer is set to 1 mm to 5 mm.

Further, both ends of the semiconductive rubber layer of the internal electrode layer are floated from the inner surface by at least 0.5 mm.

In the plastic insulated power cable connecting portion of the present invention, the premolded rubber insulating tube is connected to the conductor connecting portion exposed by stripping off the end portion of the cable, the cable insulators on both sides of the connecting portion, and the external semiconducting conductor. It is characterized in that it is attached so as to cover the layers.

In the pre-molded rubber insulating cylinder having the above structure, it is desired to make the thickness of the internal electrode layer as thin as possible. However, due to the effect of the high dielectric rubber layer, the sheet-shaped semiconductive rubber layer is thinned to 1 mm to 5 mm. It was confirmed that it was possible.

It is also desirable to make the thickness of the high dielectric rubber layer on the inner diameter side of the tip of the internal shield electrode as thin as possible.
To reduce manufacturability and cable interface electric field,
A thickness of 0.5 mm is necessary.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a half sectional view showing a structure of a premolded rubber insulating cylinder 10 according to the present invention. The pre-molded rubber insulating cylinder 10 uses ethylene propylene rubber as a base rubber, which has high insulation performance and excellent moldability, and uses the sheet-shaped internal electrode layer 11 as a semiconductive rubber layer (shielding electrode rubber layer) 111. A high dielectric rubber layer 112 that covers at least the vicinity of both ends of the semiconductive rubber layer 111.
Is formed from two layers, and the reinforcing insulating rubber layer 12 and the outer semiconductive rubber layer 13 are integrally molded on the two layers, and are configured as one part (one piece) as a whole.
The sheet-shaped internal electrode layer 11 which is a feature of the present invention is shown in FIG.
As shown in the enlarged view of (B), both ends of the semiconductive rubber layer 111 are floated from the interface (1.0 mm is floated in the embodiment) and are buried in the high dielectric rubber layer 112. Further, both ends of the semiconductive rubber layer 111 are processed with a radius of curvature which is about half the sheet thickness. In the embodiment, the thickness of the sheet-shaped internal electrode layer 11 is about 1.5 mm.

Further, in FIG. 1C, the semiconductive rubber layer 11
Only the tip region of No. 1 is covered with the high dielectric rubber layer 112.

The premolded rubber insulating cylinder 10 is molded by winding a semiconductive rubber tape and a high dielectric rubber tape around the mold core and then setting the mold (outer mold), or the internal electrode layer 11 Pre-formed into a tube shape,
After setting this on the mold core, set the mold,
Insulating rubber and semiconductive rubber are filled in a mold from an extruder to form an insulating layer and an external semiconductive layer. It is also possible to preform the outer semiconductive layer in advance and inject the insulating rubber into it.

Next, the plastic insulated power cable connecting portion according to the present invention will be described. FIG. 2 is a half sectional view showing a main configuration of an intermediate connecting portion N of a plastic insulated power cable using the above-mentioned premolded rubber insulating cylinder 10. This intermediate connection portion N is a conductor connection formed by inserting the ends of the conductor 1 exposed by stripping off the ends of both plastic-insulated power cables from both sides of the conductor connection tube 4 and compressing them. Part and the cable insulator 2 on both sides thereof, and so as to straddle the cable outer semiconductive layer 3,
Pre-molded rubber insulation cylinder 10 mounted on the outer circumference of these
Composed of and. Reference numeral 5 indicates the conductor 1 as the semiconductive rubber layer 111 of the internal electrode layer 11 of the premolded rubber insulating cylinder 10.
It is a conductor connection tube cover made of metal or conductive rubber for electrically connecting to and. Further, although not shown, a protective cover is provided on the outside so as to cover the whole, and a waterproofing portion is provided to liquid-tightly seal between both ends of the protective cover and the cable.

[0018]

According to the present invention, the high dielectric constant is obtained by covering the inner electrode layer of the pre-molded rubber insulating cylinder with a sheet-shaped semiconductive rubber layer having a thin cross section and at least the vicinity of both ends of the sheet-shaped semiconductive rubber layer. The semi-conductive rubber layer is formed with a body rubber layer, and both ends of the semi-conductive rubber layer are treated with a radius of curvature of about half of the sheet thickness and are floated from the inner surface and placed in the high dielectric rubber layer. Therefore, the internal electrode layer can be made extremely thin. As a result, the outer diameter and wall thickness of the entire product can be reduced, and the manufacturing cost of the product can be significantly reduced. Also,
Since the pre-molded rubber insulating cylinder is made compact, the assembling work of the cable connecting portion can be simplified and the cost required for forming the connecting portion can be reduced.

[Brief description of drawings]

1A is a half sectional view of a premolded rubber insulating cylinder according to the present invention, FIG. 1B is an enlarged view of an internal electrode layer, and FIG. 1C is another example of the internal electrode layer. FIG.

FIG. 2 is a half sectional view showing a main configuration of a plastic insulated power cable connecting portion according to the present invention.

FIG. 3 is a half sectional view of a cable connecting portion using a conventional premolded rubber insulating tube.

[Explanation of symbols]

1 cable conductor 2 cable insulation 3 Cable outer semi-conductive layer 4 conductor connection tube 5 Conductor connection tube cover 10 Pre-molded rubber insulation tube 11 Internal electrode layer 12 Reinforced insulating rubber layer 13 External semiconductive rubber layer 111 Internal electrode Semi-conductive rubber layer 112 High dielectric rubber layer N intermediate connection

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5G333 AA10 AA11 AB23 BA01 DA03                       EA02                 5G355 AA03 BA02 BA15                 5G375 AA02 BA26 BB43 CA02 CA14                       CB07 CB19 CB38 CB46 CB53                       DB32 EA17

Claims (4)

[Claims] 1. A pre-molded rubber insulation tube for connecting a plastic insulated power cable, which has an internal electrode layer formed of a rubber material as a base, a reinforced insulating layer and an external semiconductive layer, wherein the internal electrode layer is cross-sectioned. Is formed of a thin sheet-shaped semiconductive rubber layer and a high dielectric rubber layer that covers at least the vicinity of both ends of the sheet-shaped semiconductive rubber layer, and both ends of the semiconductive rubber layer correspond to the sheet thickness. A pre-molded rubber insulating tube which is treated with a radius of curvature of about half and is floated from the inner surface in contact with the cable insulator and placed in the high dielectric rubber layer. 2. The semiconductive rubber layer thickness of the internal electrode layer is 1
The pre-molded rubber insulating cylinder according to claim 1, wherein the pre-molded rubber insulating cylinder has a diameter of 5 mm to 5 mm. 3. The pre-molded rubber insulating tube according to claim 1, wherein both ends of the semiconductive rubber layer of the internal electrode layer are floated from the inner surface by at least 0.5 mm. 4. The premolded rubber insulating tube according to claim 1, wherein the conductor connecting portion exposed by stripping off the end portion of the cable, the cable insulating material on both sides of the connecting portion, and the outer half. A plastic insulated power cable connection part, which is mounted so as to cover the conductive layer.