JPS6361845B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electric wires such as overhead power transmission and distribution lines and overhead ground wires that suppress wind noise.

When wind blows on an installed electric wire, a Karman vortex is generated behind the wire, which generates wind noise.

This wind noise is generated at a frequency of around 100Hz at a wind speed of 10 to 20 m/s, and this sound reaches as much as 50 to 70 dB(A).

Conventionally, as a method to suppress such wind noise, a method has been proposed in which striated bodies are placed vertically on the upper and lower surfaces of electric wires, thereby disturbing the Karman vortices that occur behind the electric wires, thereby suppressing wind noise. ing.

However, in this method, since the filament is placed vertically along the entire length of the electric wire, the wind resistance increases and excessive stress is applied to the electric wire.

The present invention improves these drawbacks.

This will be explained based on an embodiment shown in FIG.

In the figure, 1 indicates an electric wire, for example, a steel core aluminum stranded wire having an outer diameter of 38.4 mm, and 2 and 2' indicate a wire body.

The filament bodies 2, 2' are made of rubber, plastic, or metal, and are placed vertically intermittently on the upper and lower surfaces of the electric wire 1 in a cross section perpendicular to the axis of the electric wire 1. The filament bodies 2, 2' on the upper and lower surfaces are attached at the same positions on the upper and lower sides, and are left missing at the same positions on the upper and lower sides.

The size of the striatum 2, 2' is 10 mm in width and thickness.
It is 4.5mm and 25cm long. The distance between each of the filament bodies 2, 2' is approximately 25 cm.

Further, as a means for fixing the filament bodies 2, 2' to the electric wire 1, the electric wire
It is fixed at

The wire gripping ring 3 is made of rubber or plastic, and as shown in FIG. ' are joined by welding, adhesive, etc. to form an open ring shape. Further, as shown in FIG.
By fitting the ring 3 into the recess 6, the ring 3 is gripped by the electric wire 1, and the filament bodies 2, 2' are placed vertically along the electric wire 1.

Note that the cross-sectional shape of the filamentary bodies 2, 2' is not limited to square, and any cross-sectional shape can be adopted, and the cross-sectional dimensions can also be selected arbitrarily; however, in the case of a rectangular cross-section, the width should be such that it does not interfere with installation. It is desirable to keep the wire to a minimum (approximately 2 mm) to avoid an excessive increase in weight. If the thickness (height after installing the wire) is too thick, the wind resistance will be excessive, and if it is too thin, the wind noise suppression effect will be reduced. Since this would be too small, it is desirable to set it to about 2 mm to 15 mm. Furthermore, even in cases other than square shapes, it is desirable to determine it in accordance with the above-mentioned square shape.

In addition, in the embodiment, as a means for vertically fixing the wire bodies 2, 2' to the electric wire 1, the wire bodies 2, 2' are fixed via a wire gripping ring 3 integrally connected to the wire bodies 2, 2'. ' is fixed vertically to the wire 1 to simplify the installation work, but the invention is not limited to this, for example, the wire bodies 2, 2' can be arranged vertically on the surface of the wire 1, , a method of wrapping and fixing with a binding wire such as plastics, tape, etc., a method of directly adhering the filament bodies 2 and 2' to the surface of the electric wire 1, etc.
In short, any method can be used as long as the filament bodies 2, 2' can be fixed vertically along the electric wire 1.

Furthermore, the mounting distance between the filament bodies 2 and 2' can be arbitrarily selected, but as will be described later, if it is too large, the wind noise suppression effect will be reduced, so it should be 30 cm or less, especially for wind resistance and aerodynamic stability (unstable The range of 5 to 30 cm is desirable, taking into account the fact that the difference in vibration is likely to occur.

Further, the length of the filament bodies 2, 2' is desirably in the range of approximately 5 to 30 cm, since wind resistance becomes excessive if the length is too long.

Furthermore, the installation interval of the filament bodies 2, 2' is
It is desirable to select both lengths so that they are integral multiples of the length of 2'. In this way, the filament bodies 2, 2' can be used as a scale for measuring the distance between the filaments, thereby simplifying the attachment work.

Furthermore, the work of attaching the filament bodies 2, 2' can be carried out at any time, regardless of whether before or after the electric wire 1 is installed.

Furthermore, the present invention can also be applied to covered electric wires.

Next, the effect of suppressing wind noise according to the present invention will be explained.

That is, a steel core aluminum stranded wire with an outer diameter of 38.4 mmφ is used as the electric wire, and a wire gripping ring 3 is integrally connected to a plurality of these wires at both ends as shown in FIG. 2 A and B, respectively. 2, 2'...width 10mm x thickness 4.5mm x
A length of 25cm (including the ring) was installed with different installation intervals for each wire. Installation interval is 50cm, 40
cm, 30cm.

When each of the electric wires constructed in this manner was placed in a wind tunnel and a wind having a wind speed of 12 m/s was blown onto the wires, the results shown in FIG. 3 were obtained.

Figure 3 shows the noise condition based on 1/3 octave band analysis.

In Figure 3, the vertical axis shows the noise level dB(A), and the horizontal axis shows the frequency (Hz). In the figure, the lines marked with an x mark are those installed at 50 cm intervals, and the lines marked △ are those installed at 40 cm intervals. The lines marked with , and * indicate the noise installed at 30cm intervals, the lines marked with ○ indicate only the electric wires with no striae attached, and the broken lines indicate the noise in the wind tunnel with no electric wires installed.

As is clear from the figure, wind noise is generated at a frequency of 63Hz, and the wires with wires intermittently attached to the top and bottom surfaces are different from the wires with no wires attached (〇 The noise level generated is lower compared to the marked line). In particular, the noise level of the wires installed at 30 cm intervals (wires marked with a *) was significantly reduced, and the situation was almost the same as when no wires were installed.

Furthermore, none of the above-mentioned cases caused excessive wind resistance.

Also, although not shown in the figure, the installation interval of the striae was set at 30 cm.
When the spacing was set as follows, almost the same results were obtained as with the 30 cm interval, and even when the length and other sizes of the striatum were changed, almost the same results as shown in Figure 3 were obtained. .

As described above, in the present invention, since the filament bodies are vertically arranged on the upper and lower surfaces of the electric wire in an intermittent manner with gaps at the same positions on the upper and lower sides, wind noise can be effectively suppressed. Moreover, since the wires are installed intermittently, wind resistance can be reduced compared to conventional products in which the wires are installed in a continuous manner.Furthermore, the wires placed on the upper and lower surfaces of the wire are missing at the same position above and below. Therefore, when fixing the filament bodies, the upper and lower filament bodies can be fixed together with one fixing means, which provides a synergistic effect such as simplifying the installation work.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of the low wind noise electric wire of the present invention, FIG. It is an explanatory view explaining a noise suppression effect. 1...Electric wire, 2, 2'...Striated body, 3...Electric wire gripping ring.

Claims (1)

[Scope of Claims] 1. A low wind noise electric wire in which a filament body is vertically laid along the upper and lower surfaces of the electric wire, characterized in that the filament body is laid vertically in an intermittent manner, with the filament bodies missing at the same position above and below. Low wind noise electric wire. 2. The low wind noise electric wire according to claim 1, wherein the distance between the filaments is 30 cm or less. 3. The low wind noise electric wire according to claim 1 or 2, wherein the filament is attached vertically to the electric wire via a wire gripping ring integrally connected to the filament.