JPS60151902A - Low noise wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a low-noise electric wire that reduces noise caused by wind on an overhead power transmission line.

Conventional low-noise electric wires use a solid spiral rod with a circular cross section that is attached to the longitudinal circumference of the wire body, and this creates protrusions on the surface of the stained wire body to reduce turbulence. I woke it up and tried to prevent wind noise. This is because, if this structure is not adopted, when the installed electric wire is blown by wind, a Karman vortex will be generated behind the electric wire, which will generate wind noise. However, even when the above-mentioned method of wrapping a solid snow spiral rod around an electric wire is adopted, the spiral rod that contributes to effective noise reduction for each electric wire size is difficult to use as the wire size increases. A2
However, as the rod diameter increases, wind pressure tends to increase, which has an undesirable effect on the installed electric wires.

The present invention has been made in view of the above circumstances, and its purpose is to suppress the increase in wind pressure by employing a spiral rod having a special cross-sectional shape in an electric wire attached with a square rod, Another object of the present invention is to provide a low-noise electric wire that can increase the effect of preventing wind noise.

That is, the present invention involves winding a plurality of thin-walled sections each having a U-shaped cross section in a spiral manner in parallel with a space between them, and forming a large number of openings in the thin-walled sections. It is characterized by increasing the turbulent flow generation effect by providing a hole. In this example, the cross-sectional shape of the thin section is described as a U-shape, but other shapes such as an L-shape or a ■-shape may also be used. In the following description, for the sake of simplicity, the opening in the profile is assumed to be a strip-shaped slit that is elongated in the longitudinal direction of the electric wire. However, it goes without saying that the opening can have any shape, such as a circle, an ellipse, a triangle, or a polygon.

FIG. 1 shows an embodiment of the electric wire according to the present invention.
On the circumference of an electric wire made of steel core aluminum stranded wire (AC8R) 30, an aluminum stranded layer 20 is provided on the outer periphery of a steel stranded wire 10. The material 1 is wound in a spiral shape. FIG. 2 is a front view of an electric wire according to the present invention, in which a plurality of thin-walled sections 1 are wound on the surface of a steel-core aluminum stranded wire 30, and the windings of each member are spaced apart (in the figure, the wires are twisted with a pinch). ),
It is wrapped in a spiral. The winding pitch l is, for example, V□ if the transmission line tower interval is 200 m to 300 m. 0
approximately 2 to 3 m. FIG. 3 is a perspective view showing the thin-walled profile 1, and the width w1 and depth d1 of the thin-walled profile Q1 are
The figure shows the standard length p of a rectangular opening having a thickness t1, and shows the thin section 1 in an untwisted state as seen from an oblique direction. Next, the width w1 depth dX thickness 1X length p of the opening of the thin section 1 will be approximately determined. This is to estimate that the torsional rigidity of the thin section 1 is low enough to be wound around the power transmission line.

Steel core aluminum stranded wire (AC
3R) has dramatically increased in size from the conventional 410 mm2, increasing in size to 810 2,1160 2, and even 1520 whale 2. These are the dimensions of AC8R, which is being used or is planned to be used in ultra-high voltage power transmission lines (UHV). For example, if we consider AC8R of 1160ven2, its diameter is 38mm. In this case, Figure 3 The width W of the thin profile 1 shown in 1 can be approximately 6 to 7 cm. In addition, the depth d is about 4 kaku, and the plate thickness t is 0.8 to 1. The length p of the wire longitudinal direction of the Otnm Here, we will numerically examine whether it is possible to wrap it around AC8R30 with the dimensions of the thin-walled form 1 described above. Now, the torsional rigidity of a rectangular open cross section as shown in Figure 3 can be calculated from the following formula: 0(GI x) = GX
a (d t' X 2 + Wt) ×α...
(1) Komuni, (Glx): Torsional rigidity, G: Out-of-structure property "' = 2 (
]-1n'), E: #f neutral number, C: Poisson's ratio,
α: 6140 4-registration reduction correction coefficient due to the presence of part j (1t+- of α differs depending on JF, the shape and size of opening j, and the number of openings j, but here it is 0.45 ~
It is set to 0.55. ) Equation (1) is rearranged by 1 and expressed as α; 0.5, then (GI
) = 0.064 Ets(2d+w) −(2
In equation 1 (2), E = 21000 kgf -, t = 0.9
Throat, d = 4 darkness, mm 6.5 victory (when entering, X (2X4am + 6.5m) = 14210kS'fz"
(3) Here, it has already been mentioned that the pitch t of the thin-walled profile 1 having the 11'j cross section shown in FIG. 2 is approximately 2.5 m. The torsional moment MX of the member 101 rotation is obtained by the following equation.

Therefore, = 17.9' to 9f-tone... (5) Now, as already mentioned, the thin section 1 is wound on a steel core aluminum stranded wire (AC8R) 30 with a diameter of 38 mm. Therefore, the value obtained by adding the depth d = 4 am of the thin section 1 to this diameter and dividing it into two, the torsional moment Mx = 17.9k.
Dividing l17f-mm k, the force F required to wrap the slit U-shaped thin section 1 around the steel-core aluminum stranded wire AC8R30 by one rotation (i.e., one pitch of 2.5 m) is only do not have. Therefore, the slitted open cross-section thin section 1 of the present invention can be wound around the steel core aluminum stranded wire 30 with sufficient strength.

Now, in Figure 1, fluid (R) flowing along the electric wire
, f, the turbulent flow transition is promoted by the presence of the thin-walled profile 1 itself (ie, the protrusion). (2) When the laminar flow separation state changes to the turbulent flow separation state due to the presence of the protrusion, the pressure fluctuation on the wire surface becomes smaller, and the energy of the wake f' becomes smaller, thereby reducing wind noise. According to the present invention, in addition to the above-mentioned wind noise reduction, the fluid f" passes through the opening j from the space h (see FIGS. 1 and 3) formed in the thin-walled profile 1. The fluid resistance υ exerted on the thin section 1 is small, and at the same time, an exchange of energy occurs between the fluid fin passing through the opening (slit) j and the fluid f′ flowing on the wire surface. , the turbulent flow effect is further enhanced.Furthermore, since the thin-walled profile 1 is wound around the wire in a helical shape, the orientation of the opening is random, which means that the wire passes through the opening j. The fluid is allowed to pass in all directions, and the phase of the flow is not even, which further enhances the wind noise reduction effect.The penetration form and penetration position of each opening j are determined by thin-walled form 1.
Depending on the size and material of the space, one can be selected arbitrarily, and the same applies to the location of multiple spaces.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within the scope of the gist.For example, in the above explanation, the thin-walled section 1 is made of steel. However, this member 1 is not limited to steel, and may be made of other metals or polymeric solid resins such as glasstic.

As described above, according to the low-noise electric wire of the present invention, an increase in wind pressure is sufficiently suppressed. Moreover, the wind noise prevention effect is greatly enhanced by the synergistic effect of the fluid f' passing over the protrusion of the thin-walled feature 1 and the fluid f//I passing through the opening j1 space. Therefore, it is possible to achieve a high rate of wind noise reduction, which is of great practical value6.Furthermore, according to the low-noise electric wire of the present invention, it is also possible to exhibit a "vibration-proofing effect" on the electric wire.

As described in detail above, the present invention makes the air flow turbulent by using a thin wire around the outer periphery of the wire, and also because the openings of the thin-walled material wound spirally roll in various directions. The fluid passing through the stain line has a more turbulent flow effect, which reduces the pressure fluctuation of the wind on the stain line surface.
It is possible to provide a low-noise electric wire having excellent features such as being able to sufficiently suppress an increase in wind pressure and effectively reducing wind noise.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a perspective view showing an example of a thin-walled profile. DESCRIPTION OF SYMBOLS 1... Thin profile, 10... Steel stranded wire, 20... Aluminum stranded layer, 3θ... Steel core aluminum stranded wire, j... Opening. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 1 Figure 2 1 jU)

Claims (1)

[Claims] A low-noise electric wire characterized in that a thin-walled profile is spirally wound around the outer periphery of the electric wire, and a large number of openings are bored in the thin-walled profile.