JP2003123542A - Aerial insulated wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent severance of an aerial insulated wire caused by stress corrosion cracking of a stranded wire conductor. SOLUTION: A tension member 1 is arranged in a center part, an annealed copper stranded wire conductor 3 comprising stranding-up of a plurality of annealed copper element wires 2 is provided on an outer side of the tension member 1, and insulating coating 4 is applied to an outer side of the annealed copper stranded wire conductor 3. Since material of the annealed copper stranded wire conductor 3 is soft annealed copper, no residual stress is accumulated during manufacture, and no stress corrosion cracking occurs after wiring. The tension member 1 in the center bears stringing tension and it maintains the aerial insulated wire in a normal stringing condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aerial insulated electric wire such as a distribution electric wire, which is installed over columns such as outdoor electric poles.

[0002]

2. Description of the Related Art Overhead insulated electric wires, such as distribution lines that are generally used at present, have a hard copper stranded wire conductor formed by twisting a plurality of hard copper strands and a plastic insulating coating such as vinyl chloride or polyethylene. It is a given structure. Hard copper is used as the conductor because the tensile strength of hard copper is large enough to bear the overhead wire tension required to maintain the overhead insulated wire between the stanchions in a proper overhead wire condition (stretched body). Is.

[0003]

As described above, the hard copper stranded wire conductor not only serves as a current path but also plays a role of bearing overhead wire tension. On the other hand, hard copper of a hard material is used. Since the strands are twisted together, the residual stress is easily accumulated inside the conductor due to the external force acting in the drawing process and the twisting process during the manufacturing. Residual stress is present in the stranded conductor When rust occurs in the stranded conductor due to infiltration of rainwater into the overhead insulated wire, the stranded conductor will eventually become rusted together with the presence of the above-mentioned residual stress. Stress corrosion cracking occurs,
If the wire breaks, it may cause a wire drop accident in the worst case.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an aerial insulated wire which is free from the risk of stress corrosion cracking.

[0005]

The aerial insulated wire of the present invention for solving the above-mentioned problems has a tension member arranged at the center thereof and an annealed copper conductor consisting of a plurality of annealed copper wires stranded on the outside thereof. It is characterized in that it is provided and an insulating coating is applied to the outside thereof.

According to a second aspect of the present invention, the tension member in the overhead insulated electric wire according to the first aspect is made of a high-strength non-metallic fiber filament.

A third aspect of the present invention is characterized in that the tension member in the overhead insulated electric wire of the first aspect is made of a copper-clad steel wire.

[0008]

1 is a sectional view of an overhead insulated wire according to an embodiment of the present invention, and FIG. 2 is a perspective view thereof. As shown in these drawings, this aerial insulated wire 5 has an annealed copper conductor formed by concentrically twisting a plurality of annealed copper wires 2 on the outer side of the tension member 1 arranged at the center as a core material. 3 is provided, and an insulating coating 4 made of vinyl chloride, polyethylene or the like is further provided on the outside thereof.

In the above-mentioned overhead insulated wire 5, the annealed copper stranded wire conductor 3 functions as a current path, but since the material thereof is soft and does not have a large tensile strength, an overhead wire tension like a conventional hard copper stranded wire conductor is used. Can not play a role to bear. However, since the tension member 1 bears the overhead wire tension of the entire wire, the overhead insulated wire can be maintained in a regular overhead wire state. Unlike the case of hard copper, the soft copper stranded wire conductor 3 formed by twisting soft soft annealed copper wires does not accumulate residual stress at the time of manufacture, and therefore stress corrosion cracking may occur in the conductor after installation. Not,
It is possible to prevent disconnection accidents and the like due to stress corrosion cracking.

As the tension member 1 disposed at the center, a high-strength non-metallic fiber filament such as aramid fiber, glass fiber, carbon fiber or copper-clad steel wire can be used. When the tension member 1 is a high-strength non-metallic fiber filament, since it is not a metal itself, there is no risk of electrolytic corrosion due to contact with a dissimilar metal even if it comes into contact with the annealed copper stranded wire conductor 3, and the tension member 1 is In the case of a copper-clad steel wire, although it is a metal itself, since its surface is made of copper of the same material as the annealed copper stranded wire conductor 3, there is no possibility of electrolytic corrosion.

[0011]

According to the aerial insulated wire of the present invention, since the soft copper stranded wire conductor serving as the current path is formed by twisting the soft soft copper wire, the residual stress is not accumulated at the time of manufacturing, and therefore the erected wire is installed. There is no possibility that stress corrosion cracking will occur in the conductor later, and it is possible to prevent the occurrence of disconnection accidents and the like due to stress corrosion cracking. And, this annealed copper conductor serves exclusively as a current path and cannot bear the overhead wire tension,
Since the center tension member bears the overhead wire tension,
The overhead insulated wire can be maintained in a regular overhead wire state.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an overhead insulated wire according to an embodiment of the present invention.

2 is a perspective view of the overhead insulated wire of FIG. 1. FIG.

[Explanation of symbols]

1 tension member 2 Annealed copper wire 3 Annealed copper stranded wire conductor 4 Insulation coating 5 Overhead insulated wire

Claims (3)

[Claims] 1. A tension member is arranged at the center,
An aerial insulated wire characterized in that an annealed copper stranded wire conductor formed by twisting a plurality of annealed copper wires is provided on the outside thereof, and an insulating coating is applied to the outside thereof. 2. The aerial insulated wire according to claim 1, wherein the tension member is made of a high-strength nonmetallic fiber filament. 3. The aerial insulated wire according to claim 1, wherein the tension member is a copper-clad steel wire.