JP2002324438A - Tree-resistant insulated electric wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tree-resistant insulated electric wire to improve abrasion resistance of a damage detecting layer and to lengthen the life after exposition of an abrasion detecting layer of the tree-resistant insulated electric wire. SOLUTION: The insulated electric wire comprises a conductor 11 covered with an insulator 12, a damage detecting layer 13 made of olefinic resin containing a lubricating agent formed over the insulator 12, and an abrasion- resistant protecting layer 14 covering the damage detecting layer 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an insulated wire,
In particular, it relates to a tree-resistant insulated wire specified in Article 86 of the Electrical Equipment Technical Standards Law.

[0002]

2. Description of the Related Art In general, the separation distance between a low-voltage overhead electric wire and a plant is described in Article 86, Paragraph 1 of the Electric Equipment Technical Standards Law, as "a low-voltage or high-voltage overhead electric wire is applied to a plant by winds constantly blowing. Facilities to avoid contact ”are required. However, low-voltage overhead power lines are not limited to places where plants do not come into contact due to "always blowing wind" .For example, when supplying electricity to mountains, remote places, etc. In some cases, low-voltage overhead electric wires and plants come into contact with each other due to wind or the like. Regarding such laying, when a low-voltage or high-voltage overhead electric wire must be laid in a place where it comes into contact with plants by wind etc. A structure in which a detection layer is applied and a wear layer is further applied thereon, and the insulated wire is coated to a uniform thickness ”(Article 86, Paragraph 2 of the Electrical Equipment Technical Standards Law). Low-voltage or high-voltage overhead electric wires laid in places that come into contact with plants due to such winds or the like are subject to Electrical Equipment Technical Standards Law No. 86.
A tree-resistant insulated wire having the structure specified in Article 2, paragraph 2 is used.

A conventional tree-resistant insulated wire has a configuration as shown in FIG. 2 as described in, for example, Japanese Patent Application Laid-Open No. 6-275140. That is, the tree-resistant insulated wire 1 has a conductor 2 made of a copper wire or a copper stranded wire covered with an insulator 3 made of polyethylene, cross-linked polyethylene or the like,
A wear detecting layer 4 made of high-density polyethylene, high-density cross-linked polyethylene or the like is coated on the insulator 3, and a wear layer 5 made of high-density polyethylene, high-density cross-linked polyethylene or the like is formed on the wear detecting layer 4. Have been. The wear detection layer 4 is provided for knowing the degree of damage caused by contact of the tree-resistant insulated wire 1 with a plant, and is colored differently from the wear layer 5. Therefore, the abrasion resistant layer 5 of the tree-resistant insulated wire 1 is worn by contact with the plant,
The wear detection layer 4 provided below the wear layer 5 is exposed, so that the wear state of the tree-resistant insulated wire 1 can be known from the exposed state of the wear layer 5.

[0004]

Such a tree-resistant insulated wire is required to have properties as an insulated wire, and when the tree-resistant insulated wire comes into contact with a plant due to wind or the like and the outer layer is worn, the properties as an insulated wire are required. May be lost. In such a case, it is necessary to replace the tree-resistant insulated wire.
When the tree-resistant insulated wire comes into contact with the plant due to wind or the like and the outer layer is worn, the characteristics as the insulated wire can be maintained by replacing the tree-resistant insulated wire.

[0005] The place where such a tree-resistant insulated wire is used is laid in a forest or a forest, and is often laid in a mountain or a remote place, and is not easily replaced. Therefore, it is desired that the tree-resistant insulated wires have abrasion resistance so that once laid, they do not need to be replaced over a long period of time. However, in conventional tree-resistant insulated wires, when the tree-resistant insulated wires come into contact with plants due to wind or the like, the outermost wear layer is easily worn away, and the characteristics of the insulated wires may be lost. ,
It is necessary to replace the tree-resistant insulated wire in a short period of time, and there is a problem that the life of the tree-resistant insulated wire is short. Furthermore, detection of damage to conventional tree-resistant insulated wires is performed visually, so during regular inspections,
In some cases, damage to the tree-resistant insulated wire (exposure of the wear detection layer) cannot be detected. In such a case, there is a problem that the wear detection layer is easily worn, and the characteristics as an insulated wire may be lost in a short period of time.

An object of the present invention is to provide a tree-resistant insulated wire capable of improving the wear resistance of the damage detection layer and improving the life of the tree-resistant insulated wire after exposure of the wear detection layer.

[0007]

In order to achieve the above object, a tree-resistant insulated wire according to claim 1 contains a lubricant on an insulator of an insulated wire having a conductor coated with an insulator. A damage detection layer made of an olefin-based resin is formed, and a wear-resistant protective layer is covered on the damage detection layer. With this configuration, according to the first aspect of the present invention, even when the wear detection layer of the tree-resistant insulated wire is exposed, the lubrication of the lubricant contained in the olefin-based resin allows the tree-resistant insulated wire to be insulated. Even if it comes into contact with plants due to wind, etc., the wear of the damage detection layer is suppressed, so the wear resistance of the damage detection layer can be improved, and the life after exposure of the wear detection layer of the tree-resistant insulated wire can be improved. it can.

[0008] In order to achieve the above object, a tree-resistant insulated wire according to claim 2 is one in which the olefin resin is made of high-density polyethylene or high-density cross-linked polyethylene. With this configuration, according to the invention described in claim 2, the wear resistance of the damage detection layer is improved,
The life after exposure of the wear detection layer of the tree-resistant insulated wire can be improved.

In order to achieve the above object, a tree-resistant insulated wire according to a third aspect of the present invention is configured such that the damage detection layer has a color different from that of the wear-resistant protective layer. With this configuration, according to the third aspect of the present invention,
Damage to the tree-resistant insulated wire (exposure of the wear detection layer) can be easily detected.

To achieve the above object, a tree-resistant insulated wire according to claim 4 is formed by covering an insulator, a damage detection layer, and a wear-resistant protective layer by simultaneous simultaneous extrusion. It is. According to this configuration, the wear resistance of the tree-resistant insulated wire can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a tree-resistant insulated wire according to the present invention will be described below. FIG. 1 shows an embodiment of a tree-resistant insulated wire according to the present invention.

In FIG. 1, a tree-resistant insulated wire 10 includes a conductor 11, an insulator 12, a damage detection layer 13, and a wear-resistant protective layer 14.

The conductor 11 is made of a copper wire or a copper stranded wire. The insulator 12 is coated on the conductor 11, and is made of a material such as high-density polyethylene (HDPE) like a normal overhead distribution line. This high-density polyethylene is prepared by a medium pressure method (100 to 150 ° C., 30 to 4 ° C. using a catalyst in which chromium oxide is supported on silica-alumina).
The Philips process is performed at 0 atm) or the low pressure process (coordination anion polymerization catalyst made by combining triethylaluminum and titanium chloride, lower aliphatic hydrocarbon is used as diluent solvent, and the pressure of the reactor is from normal pressure to 7 atm,
It is a polyethylene having a density of 0.941 to 0.965 obtained by a Ziegler method produced at a liquid temperature of 60 to 80 ° C. Increasing the density, like this high-density polyethylene, improves hardness, heat resistance, and mechanical properties. Insulated wires are generally formed by covering the insulator 12 with the conductor 11. This insulator 12 is coated to the same thickness as a conventional insulator.

The damage detection layer 13 is coated on the insulator 12. The damage detection layer 13 is colored so that the abrasion-resistant protective layer 14 is worn by contact with a plant, and when worn out, the wear state can be visually detected. . For coloring the damage detection layer 13, for example, a yellow pigment such as cadmium yellow or yellow iron oxide containing cadmium sulfide as a main component is used.

Further, the damage detection layer 13 is composed of an olefin resin containing a lubricant. As the olefin-based resin, for example, high-density polyethylene, high-density cross-linked polyethylene, or the like is used as a main component. This high-density polyethylene is a polyethylene having a density of 0.941 to 0.965 obtained by a medium pressure method or a low pressure method. The high-density crosslinked polyethylene can be obtained by subjecting the high-density polyethylene to a crosslinking treatment such as silane crosslinking.

The damage detection layer 13 is formed by adding a lubricant to the high density polyethylene or the high density crosslinked polyethylene. As the lubricant used in the present embodiment, there is silicone oil. Various silicone oils can be used for the high-density polyethylene or the high-density cross-linked polyethylene, such as higher fatty acid-modified silicone oil, methylphenyl silicone oil, dimethyl silicone oil, and dimethylpolysiloxane. Can be

As a method for incorporating silicone oil into this high-density polyethylene or high-density cross-linked polyethylene, a high-density polyethylene or high-density cross-linked polyethylene kneaded with a silicone oil into pellets is used as the main material. It is contained by mixing in an extruder with polyethylene or high density crosslinked polyethylene. Further, it can be contained in a method in which silicone oil is directly charged into a resin such as high-density polyethylene or high-density cross-linked polyethylene and mixed in an extruder.

Although the damage detection layer 13 is covered with the wear protection layer 14, the wear protection layer 14, which is the outermost layer, is worn away by contact with a plant, and the damage detection layer 13 is worn.
May be exposed. In the present embodiment, since the damage detection layer 13 contains silicone oil, even if the damage detection layer 13 is exposed and comes into contact with a tree, the silicone oil bleeds out of the damage detection layer 13. Accordingly, the damage detection layer 13 can have lubricity and can have wear resistance. That is, even in the damage detection layer 13 having a small coating thickness according to the standard, the damage detection layer 13 is not easily worn away, and the damage to the insulator 12 due to abrasion can be prevented from progressing.

Further, the silicone oil bleed out from the damage detection layer 13 also adheres to the surface of a plant or the like that comes into contact with the damage detection layer 13, so that lubricity is added to the surface of the plant, and Abrasion resistance is improved, and damage due to abrasion of plants can be prevented.

In the present embodiment, the viscosity of the silicone oil contained in the damage detection layer 13 is preferably 1 to 500 centistokes. If the viscosity of the silicone oil contained in the damage detection layer 13 is less than 1 centistoke, the lubricating property is too good, and it becomes difficult to knead during extrusion. On the other hand, if the viscosity is 500 centistokes or more, lubricity is insufficient, and it is difficult to obtain good wear resistance.

In this embodiment, the damage detection layer 1
The content of silicone oil contained in No. 3 is 1 to 1 with respect to 100 parts by weight of a main material such as high-density polyethylene.
It is desirably 0 parts by weight. When the content of the silicone oil is less than 1 part by weight, lubricity is insufficient, and when the content is 10 parts by weight or more, lubrication more than necessary is obtained, and kneading at the time of extrusion becomes difficult.

The wear-resistant protective layer 14 is the outermost layer and is made of a material such as high-density polyethylene or high-density cross-linked polyethylene. In the present embodiment, carbon black is added to the wear-resistant protective layer 14 in consideration of weather resistance from ultraviolet rays and the like contained in sunlight, and the wear-resistant protective layer 14 is colored black. Also, by using high-density polyethylene or high-density cross-linked polyethylene as the main material of the wear-resistant protective layer 14, wear resistance can be obtained.

The insulator 12, the damage detecting layer 13 and the wear-resistant protective layer 14 are simultaneously extruded using a three-layer simultaneous extruder. By using a three-layer simultaneous extruder, the outermost wear-resistant protective layer 14 can be extruded with the insulator 12 and the damage detection layer 13 having a high temperature close to the temperature at the time of extrusion. The wear resistance of the protective layer 14 can be improved.

In the present embodiment, the damage detection layer 13 has been described as containing a silicone oil as a lubricant. However, the lubricant is not limited to this, and oleic amide or stearic amide may be used. The same effect can be obtained even when a higher fatty acid amide such as described above is contained as a lubricant.

Further, in this embodiment, the damage detection layer 13 is colored with a yellow pigment, but is not limited to this, and is easily distinguished from the outermost wear-resistant protective layer 14. Any other color may be used as long as it is easy to find the state where the damage detection layer 13 is exposed.

[0026]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, even when the wear detecting layer of the tree-resistant insulated wire is exposed, the wear of the damage detecting layer is suppressed by the lubricity of the lubricant contained in the olefin resin. In addition, the wear resistance of the damage detection layer can be improved, and the life after exposure of the wear detection layer of the tree-resistant insulated wire can be improved.

According to the second aspect of the present invention, the wear resistance of the damage detection layer can be improved, and the life after exposure of the wear detection layer of the tree-resistant insulated wire can be improved.

According to the third aspect of the invention, it is possible to easily detect damage to the tree-resistant insulated wire (exposure of the wear detection layer).

According to the fourth aspect of the present invention, it is possible to improve the wear resistance characteristics of the tree-resistant insulated wire.

[Brief description of the drawings]

FIG. 1 is an overall configuration perspective view showing one embodiment of a tree-resistant insulated wire according to the present invention.

FIG. 2 is a sectional view showing a conventional tree-resistant insulated wire.

[Explanation of symbols]

 10 ………………………………………… Insulated body 13 ………………………………………………………………………… Insulator 13 … Damage detection layer 14 ………… Abrasion protection layer

Claims (4)

[Claims] An insulated wire comprising a conductor coated with an insulator, a damage detection layer made of an olefin resin containing a lubricant is formed on the insulator, and wear protection is provided on the damage detection layer. Tree-resistant insulated wire with layers. 2. The tree-resistant insulated wire according to claim 1, wherein the olefin-based resin is high-density polyethylene or high-density cross-linked polyethylene. 3. The tree-resistant insulated wire according to claim 1, wherein the damage detection layer has a color different from that of the wear-resistant protective layer. 4. The tree-resistant insulated wire according to claim 1, wherein the insulator, the damage detection layer, and the abrasion protection layer are coated by simultaneous simultaneous extrusion.