JP2003197044A - Aerial distribution line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aerial distribution line having wear resistance and weather resistance, in particular, an aerial distribution line capable of detecting damage due to contact with a tree. <P>SOLUTION: In the aerial distribution line, an outer circumference of a conductor is covered by an insulating layer, a wear detecting layer and an endurance layer in this order. It is characterized by that the endurance layer has a hue different from that of the wear detecting layer, and carbon black is added to medium density polyethylene and/or straight chain low density polyethylene. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overhead distribution line, and more particularly to an overhead distribution line.
The present invention relates to a tree-resistant overhead distribution line capable of detecting damage caused by contact with a tree. [0002] An overhead power distribution line installed near a tree is
Insulation may be cut off by vibrations caused by wind or the like when it comes into contact with trees, causing a ground fault through the trees and leading to a power outage. For this reason, in the past, grown trees were cut so as not to come in contact with electric wires, or were not brought into contact by relocating utility poles, but cutting grown trees not only costs a lot of money, This has led to environmental destruction, and there has been a problem that it is difficult to relocate utility poles due to soaring land prices. As a means for solving the problem, as shown in Japanese Patent No. 3109554, an insulating layer, an abrasion detecting layer, and high-density polyethylene having abrasion resistance and having a different color from the abrasion detecting layer are coated on the outer periphery of the conductor as an abrasion resistant layer. Tree-resistant insulated wires were developed. [0003] However, high-density polyethylene has good abrasion resistance, but not good weather resistance. Attempts to improve the weather resistance by adding carbon black have been made. There was a problem that could not be done. On the other hand, if a material obtained by adding carbon black to a high-pressure low-density polyethylene (hereinafter referred to as HP-LDPE) generally used for insulated wires is used, the weather resistance is satisfactory, but the abrasion resistance is not sufficient. However, there is a problem that it cannot be used in a place where abrasion resistance is required. SUMMARY OF THE INVENTION An object of the present invention is to provide an aerial distribution line having wear resistance and weather resistance, and in particular, an aerial distribution line capable of detecting damage due to contact with a tree. That was the task. According to the present invention, there is provided: (1) an insulated wire in which an outer periphery of a conductor is coated with an insulating layer, a wear detecting layer, and a durable layer in order; In addition, the present invention solves the problem by an overhead distribution line, which is obtained by adding carbon black to medium density polyethylene and / or linear low density polyethylene. The above-mentioned overhead distribution line of the present invention has a different hue from the wear-resistant layer before the wire reaches the required quality even if the wire comes into contact with a tree and the wear-resistant layer is damaged. By exposing the damage detection layer, it is possible to detect the degree of damage to the wires, determine the appropriate re-sealing time, and have weather resistance, so if the product damage due to abrasion is mild, It can be used as As the conductor, known materials used for electric wires and cables may be applied, and the structure is a single wire or a stranded wire. As the insulating layer, known materials used for electric wires and cables may be applied, and for example, polyethylene, cross-linked polyethylene, polypropylene, ethylene propylene rubber, butyl rubber, fluorine rubber, silicone rubber, or the like is applied. The wear detecting layer does not need to be particularly limited.
A known material such as polyethylene, crosslinked polyethylene, polypropylene, ethylene propylene rubber, butyl rubber, fluorine rubber, or silicone rubber having the same function as the insulating layer may be applied. The "durability" of the durable layer in the present invention means that it has abrasion resistance and weather resistance for a long period of time. Medium density polyethylene and / or linear low density polyethylene may be applied to the durable layer. In addition, the color may be different from that of the wear detection layer so that it can be determined whether or not the product life has expired. Medium-density polyethylene refers to polyethylene having a density of 930 kg / m ³ or more and 942 among polyethylenes produced using a catalyst by a medium-low pressure method.
kg / m ³ or less. Linear low-density polyethylene has a density of 910 kg / m ³ or more and 930 kg / m ^{3 of} polyethylene produced using a catalyst by a medium-to-low pressure method.
Less than ^three . As the above-mentioned catalyst, a Ziegler-based catalyst, a Phillips-based catalyst, a metallocene-based catalyst, and the like are applied. Among them, a metallocene catalyst is preferable in that a uniform polyethylene having few impurities can be obtained. The durable layer contains 0.2 to 3 parts by weight of carbon black, preferably 0.5 to 100 parts by weight of medium density polyethylene and / or linear low density polyethylene for weather resistance. What is necessary is just to add the weight part-1.2 weight part. If it is less than 0.2 parts by weight, the weather resistance does not improve, and if it is more than 3 parts by weight, the tracking resistance tends to decrease. As the carbon black, a known one may be applied, and for example, furnace black having excellent weatherability is applied. FIG. 1 is a cross-sectional view of one embodiment of the overhead distribution line of the present invention. In the drawing, 1 is a conductor, 2 is an insulating layer of medium density polyethylene, linear low density polyethylene, etc., 3
Is a wear detecting layer made of, for example, medium density polyethylene or linear low density polyethylene, and has a different hue from the durable layer 4 provided thereon. Reference numeral 4 denotes a durable layer coated on the outer periphery of the abrasion detecting layer 3 in consideration of contact with trees, black medium-density polyethylene having excellent wear resistance, weather resistance, and tracking resistance;
Linear low density polyethylene or the like is used. When the medium-density polyethylene and / or the linear low-density polyethylene is used for the durable layer of the overhead distribution line of the present invention, the insulating layer and the abrasion detecting means are used to improve the adhesion between the layers. It is preferable to apply the same type of material to the layer as the durable layer. Specifically, medium-low pressure polyethylene such as medium density polyethylene, linear low density polyethylene, and high density polyethylene may be applied to the insulating layer and the wear detection layer. Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. (Example 1) Conductor: Medium-density polyethylene (thickness: 2.5 mm) as an insulating layer on the outer periphery with a cross-sectional area of 120 mm ² , and medium-density polyethylene (catalyst: Ziegler catalyst, thickness:
0.6 mm, hue: white, and a medium-density polyethylene (catalyst: Ziegler catalyst, thickness: 1.0 mm, 1 part by weight of carbon black, 100 parts by weight of medium-density polyethylene, hue: black) as a durable layer. An overhead distribution line was prepared by coating with an extruder. (Example 2) conductor: linear low density polyethylene as an insulating layer on the outer periphery of the cross-sectional area 120 mm ² (thickness: 2.5 mm) and, as a wear detection layer linear low density polyethylene (catalyst: Ziegler catalyst, the thickness Length: 0.6 mm, hue: white, linear low-density polyethylene as a durable layer (catalyst: Ziegler catalyst, thickness: 1.0 mm, 1 part by weight of carbon black with respect to 100 parts by weight of linear low-density polyethylene) , Hue: black) in that order with an extruder to produce an overhead distribution line. (Example 3) Conductor: linear low density polyethylene as an insulating layer on the outer periphery of the cross-sectional area 120 mm ² (thickness: 2.5 mm) and, as a wear detection layer linear low density polyethylene (catalyst: metallocene catalyst, the thickness Thickness: 0.6 mm, hue: white, linear low density polyethylene as a durable layer (catalyst: metallocene catalyst, thickness: 1.0 mm, 100 parts by weight of linear low density polyethylene, 1 part by weight of carbon black) (Hue: black) was sequentially coated with an extruder to produce an overhead distribution line. (Comparative Example 1) conductor: high density polyethylene on the outer periphery of the cross-sectional area 120 mm ² as the insulating layer (thickness: 2.5 mm), and high density polyethylene as a wear detection layer (catalyst: Ziegler catalyst, thickness:
0.6 mm, hue: white, and a high-density polyethylene (catalyst: Ziegler catalyst, thickness: 1.0 mm, 100 parts by weight of high-density polyethylene, 1 part by weight of carbon black, hue: black) as a durable layer. An overhead distribution line was prepared by coating with an extruder. (Comparative Example 2) Conductor: High-pressure low-density polyethylene (thickness: 2.5 mm) as an insulating layer on the outer periphery with a cross-sectional area of 120 mm ² , and high-pressure low-density polyethylene (catalyst: Ziegler catalyst, thickness: 0.6 mm, hue: white, high-pressure low-density polyethylene as a durable layer (catalyst: Ziegler catalyst, thickness: 1.0 mm, 100 parts by weight of high-pressure low-density polyethylene, 1 part by weight of carbon black, hue: black) Was covered with an extruder in order to prepare an overhead distribution line. [Table 1] The following evaluation tests were performed on the overhead distribution lines of the examples and comparative examples, and the results are shown in Table 1. (Evaluation of abrasion resistance) A sample was prepared from the material of the durable layer used in Examples and Comparative Examples, and a taper abrasion test (JIS K 7204, load: 1 kgf, abrasion wheel CS) was performed.
-17, 50 rpm, 1000 times), the wear amount is 1
Those with less than 5 mg were evaluated as ○, and those with 15 mg or more were evaluated as x. (Evaluation of weather resistance) A sample obtained by cutting out the overhead distribution lines prepared in Examples and Comparative Examples to a length of 500 mm was set on a super weather resistance tester (I-Super UV tester manufactured by Iwasaki Electric Co., Ltd.) for 200 hours, and then pulled from the durable layer. A test piece was punched out, a tensile test (JIS K 7113) was performed, and the elongation was 80% compared to the initial value (the tensile strength of the durable layer before the weather resistance test).
The above was evaluated as ○, and the one with less than 80% was evaluated as ×. As described above, according to the overhead distribution wire of the present invention, even if the wire comes into contact with a tree and the outermost durable layer is worn or damaged, the required quality of the wire is not exceeded. Before, the abrasion detection layer with different hue is exposed so that the degree of abrasion of the electric wire can be detected, and it is possible to change the wire at an appropriate time. In addition, even if the degree of abrasion is low, the weather resistance is good. Therefore, it can be laid for a long time.

[Brief description of the drawings] FIG. 1 shows an example of a cross section of an overhead distribution line of the present invention. [Explanation of symbols] 1 conductor 2 Inner insulation layer 3 Wear detection layer 4 Durable layer

Claims (1)

Claims: 1. An insulated wire in which an outer periphery of a conductor is coated with an insulating layer, an abrasion detecting layer, and a durable layer in order, wherein the durable layer has a different hue from the abrasion detecting layer, and is a medium density polyethylene. And / or a linear low-density polyethylene with carbon black added thereto.