JPH03203121A - Low noise electric cable - Google Patents

Abstract

PURPOSE:To prevent wind noise by making the outer surface and both side surfaces of thin segment wires and each thick segment wire finely roughened surfaces and forming a hydrophilic coating on the roughened surfaces. CONSTITUTION:Several layers of strands consisting of a large number of twisted aluminum alloy wires are formed on a steel core 8 consisting of several steel wires 7 twisted. The strands 1 especially in the most outer layer are composed of mixed and twisted wires of a large number of thin segment wires 2 having almost trapezoid cross-section and one or several thick segment wires 3 having almost rectangular cross-section and arc planes in the outer parts, and spiral projected strips 4 based on the projected parts with height H of the wires 3 are formed in the outer circumference of the strands 1 at the most outer layer. The outer surfaces and both side surfaces of each thin segment wire 2 and thick segment wire 3 are finely roughened to have an even surface 5 and a hydrophilic coating 6 is formed on the roughened surfaces 5. Those roughened surfaces 5 are formed by mechanical method such as sand blast or chemical method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a low-noise electric wire that can cope with both wind noise and corona' noise.

[Conventional technology]

Wind noise caused by Karman vortices generated behind electrical wires where cross winds act, and corona noise caused by raindrops adhering to electrical wires during rain, have become major problems in power transmission lines whose capacity has been increasing in recent years. There is.

Conventionally, wind noise among the above-mentioned noises has been dealt with by winding a filament in a spiral around the outer circumference of the wire, or by increasing the inner thickness of some of the strands that make up the outermost strands of the wire in the radial direction of the wire. By forming a spiral protrusion on the outer periphery of the wire, the cross-sectional shape of the outer periphery of the wire becomes a non-circular shape that changes substantially in the length direction, thereby creating a Karman vortex street behind the wire where cross winds act. Low wind noise electric wires have been provided that are designed to prevent corona noise from being generated, and low wind noise electric wires that have been subjected to various surface treatments to prevent rainwater particles from adhering to the outer circumferential surface of the electric wires have been provided. AN wire is provided.

[Problem to be solved by the invention]

The above-mentioned conventional low wind noise electric wire and low AN electric wire are provided separately, and the low wind noise electric wire cannot cope with corona noise, and the low AN electric wire cannot cope with wind noise. It was impossible.

In addition, in a tank bottom that combines these two types, there are spiral striations or protrusions on the outer periphery of the electric wire, and the cross-sectional outer circumferential shape of the electric wire has a non-circular shape that substantially changes in the length direction. Therefore, although it is effective in reducing wind noise, the rainwater that flows into the spiral striations and protrusions and the boundary between them and the wire surface accumulates, and the rainwater is The water droplets fall from a large number of positions dispersed in the longitudinal direction of the wire, increasing the number of discharge points, making it impossible to suppress the generation of corona noise.

[Means for solving the invention]

The low-noise electric wire of the present invention has an outermost layer stranded wire in which a groove bottom is formed by a mixed twist of a large number of thin-walled segment wires and one or several thick-walled segment wires, and the outer periphery of the outermost layer stranded wire is A spiral protrusion is formed by the thick segment wire, and the outer surface and both side surfaces of each thin segment wire and each thick segment wire are made into finely uneven and rough surfaces. A hydrophilic film is formed on the surface.

[For production]

The spiral protrusion formed on the outer periphery of the outermost stranded wire, which is made of thick-walled segment wires, makes the cross-sectional outer peripheral shape of the wire substantially non-circular in shape and changes in the length direction, making it difficult for the wire to be exposed to cross winds. Prevents the generation of Karman vortex array behind it.

The hydrophilic film on the outer surface of each thin-walled and thick-walled segment wire reduces the surface tension of rainwater that tends to rise up into a spherical shape, and the finely uneven rough surface promotes flow and diffusion of rainwater to the surrounding area.

The finely uneven and rough surfaces on the side surfaces of each of the thin and thick segment wires create a small gap between the side surfaces of mutually adjacent segment wires. The existence of this minute gap and the surface tension reducing effect of the hydrophilic film on the uneven surface combine to prevent capillary action from occurring between the sides of each segment tension line. Rainwater is drawn into the twisting gaps inside the twisted wires due to capillary action.

〔Example〕

1 to 3 show an embodiment of the low-noise electric wire according to the present invention, in which a large number of aluminum alloy wires are placed on a copper core 8 consisting of a plurality of twisted steel wires 7. Twisted wires made by twisting together are provided in multiple layers. In particular, the outermost stranded wire 1 has a large number of thin segment wires 2 having a substantially trapezoidal cross section and one to several wires (in the illustrated embodiment, two wires are arranged adjacent to each other at symmetrical positions of 180 degrees around the circumference, for a total of 4 wires). The groove bottom is formed by a mixed twist of thick segment wires 3 having a substantially rectangular cross section and an arcuate outer surface, and a protrusion of height H of the thick segment wires 3 forms a groove. As shown in FIG. 2, a spiral protrusion 4 is formed on the outer periphery of the outermost stranded wire 1.

The outer surface and both side surfaces of each of the thin segment wires 2 and the thick segment wires 3 have a finely uneven and rough surface 5 as shown in FIG. A hydrophilic film 6 is formed.

Here, the finely uneven and rough surface 5 can be formed by mechanical methods such as blasting such as shot blasting or sandblasting, polishing with steel wire or steel wool, or hydrofluoric acid.

It can be formed by a chemical method such as dipping treatment using an aqueous solution of elatin such as sodium fluoride, ammonium fluoride, or hydrochloric acid. Further, the hydrophilic film 6 on the uneven surface 5 is coated with boiling water on the rough surface 5.

Either spraying pressurized steam, steam added with ammonia or amines, etc., immersing the wire with the rough surface 5 formed therein, or anodizing the rough surface 5, or subjecting it to chromate treatment. It can be obtained as a boehmite film, an anodic oxide film, a chromate film, etc.

〔Effect of the invention〕

According to the low noise electric wire according to the present invention, the following effects can be obtained.

That is, the spiral protrusions 4 on the outer periphery of the electric wire formed by the thick-walled segment wires 3 prevent the generation of a Karman vortex street behind the electric wire where cross winds act, thereby preventing the generation of wind noise.

In addition, the surface tension that prevents rainwater adhering to the outer peripheral surface of the electric wire from building up in a spherical shape is reduced by the hydrophilic coating 6 on the outer surface of each thin segment wire 2 and each thick segment wire 3, and The rough surface 5 promotes flow diffusion to the surroundings.

The rainwater, which has lost its surface tension and flowed and diffused to the surroundings, is sequentially taken into the twisting gap inside the stranded wire by the minute gap between the side surfaces of the segment wires and the capillary phenomenon that occurs in the gap. Therefore, the electric wire does not have protrusions caused by adhesion of raindrops on its outer circumferential surface over its entire span, and rainwater is prevented from falling as water droplets from numerous points dispersed in the longitudinal direction of the electric wire. The generation of corona noise is prevented.

[Brief explanation of drawings]

The drawings show an embodiment of the low-noise electric wire according to the present invention, in which FIG. 1 is a cross-sectional view, FIG. 2 is a side view, and FIG. 3 is a diagram showing a segment wire constituting the outermost layer stranded wire. It is a partial view which expanded and showed the surface state of an outer surface and a side surface. In the figure, 1 is the outermost layer stranded wire, 2 is a thin segment wire, 3 is a thick segment wire, 4 is a spiral protrusion,
5 is a rough surface with fine irregularities, and 6 is a hydrophilic film. 0f

Claims (1)

[Claims] Thin segment wire (2) with many outermost layer strands (1)
and one or several thick segment wires (3), and a spiral protrusion formed by the thick segment wires (3) is formed on the outer periphery of the outermost layer twisted wire (1). (4)
is formed, and the outer surface and both side surfaces of each thin-walled segment wire (2) and each thick-walled segment wire (3) are made into a finely uneven rough surface (5), and the rough surface (
A low-noise electric wire characterized in that a hydrophilic film (6) is formed on the top of (5).