JPH03196413A - Low noise electric wire - Google Patents

Abstract

PURPOSE:To prevent occurrence of wind noise of an electric wire even when a side wind blows against the wire by forming the wire by twisting a large number of segment stands so as to make the whole peripheral section of the outermost layer of stranded wires an ellipse. CONSTITUTION:Stranded wires composed of a number of aluminum alloyed wires twisted are arranged in plural number of layers on a steel core 4 formed by twisting plural steel wires. In particular, stranded wires 1 of the outermost layer are composed of a number of segment strands 2 twisted so as to make the whole outer peripheral section an ellipse. A water holding groove 3 having a semicircular arc section is provided on the outer surface of at least one of these segment strands 2 extending in the longitudinal direction of the segment strand 2. A cross section of each stranded wire 1 of the outermost layer is varied rotatively from (A) to (B), (C) and (D) in order and return to the state of the (A) again till the completion of one pitch of twist. That is to vary from the vertical state (A) of the longitudinal axis of the ellipse to the state advancing a twist at 1/4, 1/2, 3/4 for (B), (C), (D) respectively and the stranded wires 1 of the outermost layer form like a twisted pillar having an elliptic cross section.

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 L 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. ing.

Conventionally, wind noise among the above noises has been dealt with by winding a filament in a spiral around the outer circumference of the wire, or increasing the thickness of some of the strands that make up the outermost stranded wire 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. In order to prevent corona noise, various surface treatments have been applied to the outer circumferential surface of the wire to prevent rainwater particles from adhering to it. A low AN electric wire is provided.

[Problems 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 corona noise. AN wires were unable to cope with wind noise.

In addition, in a configuration that combines these two types, spiral filaments or protrusions are present on the outer periphery of the wire, resulting in a non-circular shape in which the cross-sectional outer periphery shape of the wire substantially changes in the length direction. Although this is effective in reducing wind noise, flowing rainwater tends to accumulate in the spiral striations and protrusions as well as the boundary between them and the wire surface. Since water droplets fall from a large number of positions dispersed in the longitudinal direction of the wire and increase the number of discharge points, it becomes impossible to suppress the generation of corona noise.

The present invention has been made in view of the above points, and an object thereof is to provide a low-noise electric wire that can cope with both wind noise and corona noise.

[Means to solve the problem]

In order to achieve the above object, in the low-noise electric wire of the present invention, the outermost layer stranded wire is constructed by twisting a large number of segment wires so that the cross-sectional outer peripheral shape as a whole is elliptical, and A water retention groove extending in the longitudinal direction of at least one of the segment wires was carved on the outer surface of at least one of the segment wires.

[For production]

The outermost twisted wire does not generate a Karman vortex street behind it even if a crosswind acts on it.

Since the outer surface of the outermost stranded wire is smooth in the circumferential direction, the flow of rainwater adhering to the broken wire surface in the wire circumferential direction is extremely smooth. Rainwater flowing in the circumferential direction of the electric wire is partially captured in water retention grooves carved on the outer surface of the segment wire.

The rainwater that has flowed into the water retention groove is held in the groove by its surface tension, viscosity, etc., and flows along the length of the groove until it reaches the lowest point of the wire sag, and then falls from there. .

〔Example〕

1A to 1D show an embodiment of the low-noise electric wire according to the present invention, in which a large number of aluminum wires are placed on a copper core 4 made of a plurality of twisted steel wires. Twisted wires made of twisted alloy wires are provided in multiple layers. In particular, the outermost layer strand l is composed of a large number of segment wires 2 twisted together so that the overall cross-sectional outer peripheral shape is elliptical, and the segment wires 2 are
At least one of the strands (in the illustrated embodiment, the one located on the long axis of the ellipse of the stranded wire l) is carved with a water retention groove 3 having a semicircular arc cross section extending in the length direction thereof. There is.

The outermost layer strand 1 is sequentially moved from the state shown in FIG. 1(A) to the state shown in FIG. 1(B) until one pitch of the twist is completed.
The cross-sectional shape changes rotationally to the state shown in C), (D), and again to (A). Figure 1 (A
) is the initial state, and the figure (B) shows the state where the twist has advanced by 1/4 pitch, and at this time the short axis of the ellipse is vertical. The figure (C) shows the position where the twist has progressed by 172 pitches and the long axis of the ellipse becomes vertical again by 1806 rotations, and the figure (D) shows the position where the twist has progressed by 3 habitches.

Therefore, the outermost layer strand 1 has the shape of a twisted column with an elliptical cross section.

Note that the shape of the water retention groove 3 is not limited to the semicircular arc shape of the illustrated embodiment, but may be U-shaped, 7-shaped, etc., and the depth and width of the groove are determined to produce a rainwater retention effect. 1 to tighten
It is preferable to set it to about 2 mm.

〔Effect of the invention〕

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

That is, since the outermost layer strand 1 has the shape of a twisted column with an elliptical cross section, even if a cross wind acts, a Karman vortex>J is not generated behind it, and wind noise is prevented from occurring.

In addition, rainwater adhering to the outer peripheral surface of the electric wire during rainfall flows in the circumferential direction on the outermost layer stranded wire 1 having a smooth outer surface, reaches the water retention groove 3, and is retained inside the water retention groove 3. flows sequentially along the length of the wire until it reaches the lowest point of wire sag. Therefore, over the entire span of the wire, protrusions due to adhesion of raindrops do not occur on the outer peripheral surface of the wire, and rainwater is prevented from falling as water droplets from numerous points dispersed in the longitudinal direction of the wire. The generation of corona noise is prevented.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a low-noise electric wire according to the present invention. In the figure, 1 is the outermost layer stranded wire, 2 is the segment wire, and 3 is the outermost layer stranded wire.
is a water retention groove. ! 11! -One! 1- Q! 1"

Claims (1)

[Claims] The outermost layer stranded wire (1) is constituted by twisting a large number of segment wires (2) so that the cross-sectional outer peripheral shape as a whole is elliptical, and A low-noise electric wire characterized in that a water retention groove (3) extending in the longitudinal direction of the electric wire is carved on at least one outer surface of the electric wire.