JPS5826412A - Power cable with water shielding layer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to rubber. This invention relates to the improvement of plastic insulating capacitors, especially the water repellent layer.

Traditionally, rubber with a layer of water. As shown in Figure 1 (A), (l), the plastic insulated electrical cable has conductors 1,
Insulating layer 2. Shiyahei layer 6. It consists of a 4° sheath 5 made of rainwater tape. In Figures (A) and (B), the shimmering tape 4 is provided under the sheath 5 at a position different from the outer periphery of the insulating layer 2.

(A) and (B) Both are water-repellent tapes 4 with a laminated structure in which metal foil is sandwiched between the insulating layer 2 and the sheath 5 with a plastic film to prevent insulation deterioration due to water intrusion.
It is tied vertically or spirally wound to prevent water from penetrating from the outside.

In this case, the metal foil used is an alloy ship containing a few percent of each of aluminum, lead, or antimony, and the place where the water tape is placed is placed under the sheath as described above. There are two types: one integrated with the sheath, and one provided on the outer periphery of the insulating layer and integrated with the insulating layer by adhesive.

Rubber and plastic ←=4 have a large volumetric expansion coefficient due to heat, and therefore the outer diameter of the insulator changes by about 3% due to thermal expansion and contraction caused by energization. Along with this, the water tape also undergoes repeated strain of 7 to 3%, but at this time, the water tape's aluminum foil, lead foil, or alloy lead foil will crack after being repeated several thousand times, so the water tape The effect will be lost.

The present invention has been made in view of the points mentioned above, and the present invention has been made in consideration of the points mentioned above.
We provide rubber and plastic insulated capeple with a water layer that maintains the water effect.The feature is that a metal foil with a tensile elongation at break of 50% or more is sandwiched between rubber or plastic film as a water tape. This is due to the fact that it was used.

A cross-sectional view of an embodiment of the rubber with water barrier layer and plastic insulated capeple of the present invention is shown in FIG. do.

FIG. 2(A), (In l, 1 is a conductor and 2 is an insulating layer.

6 is a poppy layer, 4 is a poppy tape, and 5 is a sheath.As shown in FIG. The metal foil chopsticks and water tape are superplastic metal foils having an elongation at break of 50% or more in the temperature range of cable use (20 to 10°C).

Superplastic metals include the following:

(1) Zu〈. Lead, alloy, (2) bismuth. Indium alloy.

(3) Bismuth. (4) Cadmium, zinc alloy.

(5) Lead. Cadmium alloy, (6)zuso, bismuth alloy.

(7) Zinc, aluminum alloy, etc.

The water tape shall be as follows.

(1) The coating method may be vertical coating or spiral wrapping.

(2) Rubber for laminate materials. The plastic film may be insulating or semiconductive with carbon mixed therein.

(3) It shall be applied to the outer periphery of the insulator or the inner periphery of the sheath, and in each case, it may or may not be integrally bonded with the insulator or sheath.

The metal foil of the waterproof tape using the rubber and plastic insulating capeple with a water-blocking layer of the present invention has a laminate structure in which rubber and plastic films are sandwiched, and the metal foil is a superplastic metal.

Lead alloy ones are better. To confirm this, aluminum foil, lead foil, skirting board, lead alloy foil laminated with rubber or plastic film on one side (■) and laminated on both sides (II) were subjected to 2% repeated elongation. As a result, cracks occurred in each metal foil at the number of times shown in Table 1.

Table 1: The number of times until cracking occurs varies slightly depending on the thickness of the metal foil, but the values in the table above are data for thicknesses of Jμm to Qpm. Also, 71,000 times is a repeated growth equivalent to 30 years.

In addition, the table above! It should be noted that a lead alloy containing 20% lead and 5% lead was used.

In addition, as shown in Figure 4, the elongation at break of lead alloy at low speed at jO0C is large, so it has a high resistance against repeated strain, so the results shown in Table 1 were obtained. considered to be a thing.

Table 2 shows superplastic alloys that have twice the elongation at break of lead in the cable operating temperature range (20 to 100°C), that is, more than 50% elongation at break. It can be said that it is suitable as a metal foil.

Table 2 The electric cable with a water barrier layer of the present invention has a breaking elongation of 50
% or more of superplastic metal foil sandwiched between rubber and plastic film, the metal foil of the waterproof tape will absorb the thermal expansion of the cable insulation. It does not break even if subjected to large repeated strains due to shrinkage, and can maintain its effectiveness as a water tape, reliably preventing the cable insulator from deteriorating due to water.

-4- As stated above, the present invention is practical because the insulating layer is thick and therefore the insulator expands. The change in outer diameter due to shrinkage increases the repeated strain on the comb or water tape2.
Special Takada rubber for 2kV and above. Plastic insulated cage
This is applicable to pull.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional power cable with a water layer.
(A) The chopsticks and water tape are under the sheath, (B) The poppies and water tape are on the outer periphery of the insulator. Figure 2 is a cross-sectional view of an embodiment of the electrical cable with a water-blocking layer of the present invention, and (4) is (1) Water tape is on the outer periphery of the insulating layer, (1) Water tape is under the sheath, Fig. 3 is an explanatory diagram of the structure of the water tape, Fig. 4 is a piece of water, and lead-containing foil is used. It is a low-speed elongation characteristic diagram of 1...conductor, 2...insulator, filter...shiyahei layer,
4...Shiyamizu tape, 5...Sheath, 41...Gold M i, 42...Rubber. plastic film. 59- Influence, m57

Claims (1)

[Claims] 1. A metal foil made of a superplastic alloy having a breaking elongation of 0% or more in a temperature range of 20 to 700°C between an insulator and a sheath in a rubber or plastic insulated case. An electric caple with a water layer, characterized by a water-repellent tape with a laminated structure sandwiched between rubber and plastic film, which is vertically attached or spirally wound. 2. The electrical cable with a water barrier layer according to claim 1, wherein the superplastic alloy metal foil has a hem of 10% or more and is not a lead alloy metal foil.