JPH03108205A - Manufacture of low-luminosity overhead cable - Google Patents

Abstract

PURPOSE:To better the corona characteristic of an overhead cable and also to provide the low luminosity thereof by intertwisting a plurality of element wires, each obtained through the process of coloring a metallic wire body and then roughing the surface of the colored wire body, to form the outermost layer of an aluminium cable steel reinforced. CONSTITUTION:A metallic wire body 120 forming the outermost layer element- wire 12 of an aluminium cable steel reinforced(ACSR) 1 is colored on its surface by introducing it into a coater 3, such as an electrostatic coater or the like while traveling it in a direction indicated by an arrow in the Figure. The resultant metallic wire body 120 coated is then introduced into a drier 4 which dries and hardens the coating applied on the surface of the wire body 120. Thereafter, a sandblast that sand S is upon the surface of the metallic wire body 120 by a sprayed spray gun 5 is made for roughing the surface to manufacture the outermost element-wire 1. A plurality of the manufactured element-wires 12 can be accordingly intertwisted to form the outermost layer of the ACSR 1 so as to obtain the resultant ACSR 1 providing low luminosity.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing overhead electric wires such as steel-core aluminum stranded wires (AC3R) and overhead ground wires in which the brightness of the surface thereof is reduced. It is something.

[Prior art and its problems] Overhead electric wires used in ultra-high voltage overhead power transmission systems are mainly bare electric wires called AC8R, which are made by twisting aluminum wires or aluminum alloy wires around a high-strength steel wire core. Such bare electric wires are used for hydroelectric power plants in the mountains and thermal power plants on the coast.
Electric power is transmitted from nuclear power plants across mountainous regions to power demand areas in cities and industrial areas by hanging on steel towers.

By the way, since bare electric wires such as AC3R are exposed metal wires, it has been seen as a problem for some time that when they are installed in mountainous areas, they do not blend in with the surrounding environment and spoil the beautiful scenery. In other words, the glare of bare metal overhead power lines is extremely out of proportion to the natural scenery, such as the green of the trees and the blue of the sky.

To solve this problem, the conventional method was to roughen the surface of the metal wire that makes up the outermost layer of the overhead wire by sandblasting it, thereby removing the gloss from the surface of the wire and suppressing glare. It has been commonly taken. It is also known that by roughening the surface of the electric wire, raindrops can be prevented from forming during rain, thereby preventing the generation of corona (Japanese Patent Publication No. 36-14185). In addition, a method has been proposed in which the surface of overhead wires is colored green or gray using electrostatic painting or other methods, and matched to the color of the mountains and sky (Japanese Patent Application Laid-Open No. 53-83092). Even if you sandblast the outermost AC3R wire using only sand such as A1203), the surface will be roughened and light will be reflected diffusely, resulting in a decrease in reflectance, but since the overall color tone of the overhead wire is still white, When the overhead electric wire is installed in a mountainous area, it is difficult to get rid of the sense of discomfort. In addition, in the method of coloring the surface of overhead electric wires, it is possible to select the desired color tone, so it is possible to reduce the brightness by coloring to match the surrounding environment, but on the other hand, the surface of the electric wires is smoothed by paint. Therefore, when it rains, raindrops are generated and corona discharge is likely to occur.

In view of the above problems, as a method of obtaining an overhead electric wire that can reduce brightness and have good corona characteristics, the surface of the outermost layer of wire is first roughened by sandblasting etc., and then a dark color is applied thereon. Many methods have been proposed to
No. 15984, Utility Model Publication No. 54-56785). However, according to this manufacturing method, since the paint is applied on the minute irregularities formed by the surface roughening treatment, the paint fills the minute depressions and almost smoothes the rough surface, resulting in a reduction in brightness. Although this can be achieved, there is a problem in that the corona characteristics deteriorate.

Therefore, an object of the present invention is to provide a method for manufacturing an overhead electric wire that has good corona characteristics and can reduce brightness.

[Means and effects for solving the problem] The method for manufacturing a low-brightness overhead electric wire of the present invention includes a method for producing a low-brightness overhead electric wire by coloring a metal wire body and subjecting the surface of the colored wire body to a roughening treatment. The present invention is characterized in that a plurality of wires are twisted together in the outermost layer, the surface of the stranded wire made of twisted metal linear bodies is colored, and the surface of the blue stranded wire is subjected to a roughening treatment.

In other words, unlike the conventional method, the pre-colored metal linear body or stranded wire is subjected to surface roughening treatment, so the problem of the paint filling in minute recesses as in the conventional method is solved, and the surface is rough. Since it is colored and has good corona properties, it is possible to manufacture overhead wires with low brightness. Note that it is necessary to select conditions for the above-mentioned surface roughening treatment that will not cause the paint to peel off.

[Example] An example of the present invention will be described in detail below based on the drawings.

FIG. 1 is an explanatory diagram showing a method for manufacturing a low-brightness overhead electric wire according to the present invention, and FIG. 2 is a cross-sectional view of a steel-core aluminum stranded wire 1 (hereinafter referred to as AC3R) manufactured by the method of the present invention. FIG. 3 shows an enlarged sectional view of the main part.

In these figures, first, a metal wire body 120 made of, for example, aluminum or aluminum alloy, such as the outermost layer strand 12 of AC3RI, is introduced into a coating device 3, such as an electrostatic coating device, while running in the direction of the arrow in the figures. The surface of the metal linear body 120 is colored. As paints that can be used here, various paints such as polyurethane paints, acrylic paints, polyester paints, epoxy paints, vinyl paints, and alkyd paints can be used. In addition, the color of the paint can be selected appropriately to match the surrounding background of the area where AC5RI can be constructed, but generally black or gray colors, deep green or gray-green colors are selected. .

The coated metal linear body 120 is then transferred to the drying device 4
The paint applied to the surface of the linear body 120 is dried and solidified. Thereafter, sand blasting is performed by spraying sand S such as alumina onto the surface of the metal linear body 120 using the spray gun 5 to roughen the surface, thereby completing the production of the outermost layer element [12]. Note that when performing sandblasting, it is necessary to select conditions under which the paint on the surface of the metal linear body 120 does not peel off. That is, it is sufficient to take measures such as increasing the traveling speed of the metal linear body 120 or lowering the pressure of the spray gun 5 than under normal sand brushing conditions. Further, as another means for the surface roughening treatment, for example, a transfer method in which the metal wire body 120 is passed through a guide roll in which minute irregularities are formed in the guide groove to roughen the surface can also be applied.

By twisting a plurality of 12 strands thus obtained into the outermost layer of AC3RI as shown in FIG. 2, AC3RI with reduced brightness can be obtained. That is, as shown in FIG. 3, a dark-colored layer 13 is formed on the surface of the outermost layer strand 12 by the paint adhesion layer applied by the above-mentioned painting. Note that 2 is a steel core made of twisted steel wires, and 11 is a normal aluminum wire.

Also, although not shown in the drawings, unlike the above manufacturing method, AC3R
The same effect as the above method can be obtained by manufacturing AC3R, then applying paint to the surface of AC3R, drying and solidifying it, and then roughening the surface to reduce the brightness. I can do it.

A gray-green acrylic solvent-based thermosetting paint was applied to a metal linear body with a diameter of 4.8 mm using an ordinary electrostatic coating device, and after drying, the linear body was coated at a linear speed of 20 m/min. While running (1.5 times the linear speed of normal sandblasting)
Alumina powder having a particle size of 100 μm was sprayed onto the surface using a spray gun at a compressor gauge pressure of 7 kgt/cn.

The surface of the wire thus obtained was roughened and had a gray-green color. These wires are twisted in the outermost layer AC3
When R was manufactured, its appearance was reduced in brightness, and the desired low brightness AC3R could be obtained.

[Effects] According to the method for manufacturing a low-brightness overhead electric wire of the present invention as explained above, the surface of the overhead electric wire is colored compared to the case of reducing the reflection of the surface of the overhead electric wire by sandblasting alone, which is generally performed. Therefore, the brightness can be lowered. Also,
Since the surface of the metal wire or stranded metal wire, which is the outermost layer of the overhead electric wire, is colored in advance and then subjected to roughening treatment, there is a problem that the paint smoothes the roughened surface as in the conventional method. The present invention has excellent effects, such as being able to reduce brightness and obtain an overhead wire with good corona properties.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the method for manufacturing a low-brightness overhead electric wire according to the present invention, FIG. 2 is a cross-sectional view of a steel-core aluminum stranded wire 1 manufactured by the method of the present invention, and FIG. An enlarged sectional view of the main part is shown. 1...AC3R, 12...Outermost layer strand, 120...
・Metal linear body, 13...Dark color layer, 3...Coating device,
4... Drying device, 5... Spray gun patent application Mitsubishi Cable Industries Co., Ltd. Representative Director Junzo Yuki Figure 1 Figure 2 Figure 3 Figure 1

Claims (2)

[Claims] (1) Production of a low-brightness overhead electric wire, which is characterized in that a plurality of wires obtained by coloring a metal wire body and roughening the surface of the colored wire body are twisted together in the outermost layer. Method. (2) A method for producing a low-brightness overhead electric wire, which comprises coloring the surface of a stranded wire made of twisted metal wire bodies, and subjecting the surface of the colored stranded wire to a roughening treatment.