JPS601705A - Low noise and low vibration electric 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] [Background and Objectives of the Invention] The present invention relates to a low-noise, low-vibration line that can significantly reduce noise and vibration caused by wind pressure from overhead power transmission lines or overhead ground wires. .

Since overhead power lines and overhead ground wires are installed high up on steel towers, it is difficult to avoid noise caused by wind pressure and vibrations caused by them. I!
I Noise has a negative impact on environmental conditions, and wind pressure vibrations pose a risk of causing accidents such as fatigue failure of electrical wires.

It has been discovered that wind noise in the former case can be suppressed by winding a spiral wire around the outer circumference of the electric wire, and the applicant has already made a proposal, but in this case, a spiral wire manufactured separately from the electric wire is prepared. Moreover, it is necessary to attach the wires to the wires using an airborne weight after the overhead wires are installed, which inevitably involves dangerous work.

Furthermore, since the wires will protrude from the surface of the wire,
It is related to corona characteristics and comes with the problem of audio pull noise. Further, the weight of the electric wire increases due to the spiral strands, and an increase in wind pressure due to the protruding spiral strands must be considered, which is not necessarily favorable for the wind pressure vibration.

2- Research on wind noise on power transmission lines has made great progress in recent years, and it has become possible to predict in advance the routes where JIIISI noise is likely to occur. Therefore, instead of attaching a separate member to the electric wire to prevent wind noise, the electric wire itself can be made into a special shape that does not generate noise, and if the special electric wire is installed in a dangerous area where such wind noise is expected to be generated, the above-mentioned problem can be avoided. All such problems will be resolved.

Based on this knowledge, the applicant has already proposed an electric wire having a cross-sectional configuration as shown in FIG.

In this method, at least the outermost twisted wire layer of the electric wire is composed of segment wires, and a step surface is formed in the radial direction by the thinner wires 1- and the thicker wires 2-,
A low stepped surface 10'a and a high stepped portion 10-b are formed symmetrically.

It has been found that the electric wire 10- configured in this manner not only has an excellent low noise effect, but also has extremely low wind pressure vibrations and can extremely reduce audible noise caused by corona.

The present invention aims to provide an electric wire that further improves the already proposed electric wire and exhibits even more significant noise reduction and vibration prevention effects.

[Detailed Summary of the Invention] That is, the gist of the present invention is to configure at least the outermost stranded wire of the stranded wires from segmented wires, to form a symmetrical step surface on the outer peripheral surface thereof, and to form a symmetrical step surface on the outer circumferential surface thereof, and to In particular, by forming another step on the higher step side, the wire has a greater noise prevention effect than the previously proposed wire shown in Figure 1. It has been discovered that the anti-vibration effect can be significantly increased.

[Embodiment] What is shown in FIG. 2 is a cross-sectional view showing one embodiment of the electric wire 10 according to the present invention, and the inner layer portions are each composed of strands having a circular cross section. As in the case shown in the figure, even the inner layer may be composed of segment 3 wires.

Therefore, the outermost stranded wire layer is made by twisting together three types of segment wires 1, 2 and 3 having different thicknesses in the radial direction of the electric wire, and the wires 1, 1 having the smallest thickness.
Next, the thicker wire 2.2 is arranged symmetrically as shown in FIG. However, this symmetry does not mean symmetry in a geometric sense, but rather a relationship that is roughly relative to each other.
There may be some discrepancies in the numbers.

A low step surface 10a is formed by the strands 1, 1, and the strands 2
, 2, a higher step portion 10b is formed.

In this state, there is no difference from the case shown in FIG. 1 described above. The present invention creates a third step surface 10 by mixing and twisting thicker wires 3 in this high step portion 10b.
Its characteristic lies in the formation of c. In this embodiment, the number of mixedly twisted strands 3 is one within one stepped surface 10b, but it goes without saying that a plurality of strands may be used. Its position is not necessarily limited to the central position of the stepped surface 10b.

FIG. 3 is a schematic diagram showing the external configuration of FIG. 2. The outer diameter formed by the step surface 10b is D1 step surface 1
Figures 4 and 6 show the wind tunnel experiment results when the difference between 0a and 10b is 11, the difference between step surfaces 10b and 10c is t2, the central angle of step portion 10b is θ1, and the central angle of step surface 10C is θ2. Ta.

FIG. 4 is a diagram showing the effect of the value of j2/jt on wind noise reduction. j2/jt=o indicates the case of the previously proposed configuration shown in FIG. In this case, the central angle θ1=90',
t 1 =25Ill, D=40m. The strands shown in FIG. 2 and 3 for forming the stepped portion 100 are mixed and twisted to this, and θ2/θ1=115 and θ2/θ1=215.
So that θ1 = 90', D = 40#1lI
Wires with different values of t 2 /l 2 were prepared at I and a wind tunnel experiment was conducted at a wind speed of 15 m/s to investigate the relative level reduction.

As a result, it is clearly seen that when j2/j+=0.5 or less, the effect of the stepped surface 10C cannot be achieved, but when it becomes 0.5 or more, the relative level drops extremely significantly. Such experiments were attempted with other commercial-sized electric wires of different diameters, but the results were largely the same and slightly different. And θ1
It was also found that when θ2 is the same, the smaller θ2 is, the more remarkable the effect is. However, if it is made too small, a peak will be formed in some areas, so care must be taken to prevent corona noise. The preferred range of θ1 is 60°<θt<1
It was 20'.

Further, FIG. 6 is a plot of the ratio of lift fluctuations due to wind pressure between the conventional 810wAA C3'R (steel core aluminum stranded wire) and the 810dAC8R according to the present invention.

810mJAC8R outer diameter 38mm, 81 according to the present invention
0mJAC8R is D=38mm1j + in Figure 3
= 2mm, t2 = 1mm, so t2/11=0
．． 5, e+ = 90°, θ2/θ+ = 115.

As is clear from FIG. 6, as the wind speed increases, the lift of the electric wire according to the present invention decreases significantly,
It has also been found that wind pressure vibrations have been significantly reduced, and that it is now possible to omit the damper for absorbing the vibrations of the electric wires, which was indispensable in the conventional AC8R. Although such a vibration-preventing effect can be sufficiently observed even with the shape shown in FIG. 1, in the case of the present invention, it is even more noticeable in the same way as the noise-preventing effect described above.

Although the wires 1 and 2 need to be segment wires, the wire 3 may have a circular cross section.

Furthermore, when forming a stepped surface, 'loa' as shown in Figure 2 is used.
, 10b and 10C may be replaced by four stages 10a, 10b, 10c and 10d as shown in FIG. It has also been found that the effect can be further improved even if o2/θ1 becomes large by providing multiple stages in this manner.

[Effects of the Invention] The reason why the electric wire according to the present invention has the remarkable noise prevention effect and vibration suppression effect as described above is that its special outer layer structure greatly suppresses the generation of Karman vortices and prevents air-fluid separation. This is thought to be to calm down the phenomenon.

7- By providing such wires, noise can be prevented without the need for special accessories, and the number of dampers on the transmission line can be reduced depending on the effect of reducing the wind input energy itself. The ability to reduce or eliminate this is noteworthy and should be highly appreciated in industry.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the already proposed electric wire, Fig. 2 is a cross-sectional view showing an embodiment according to the present invention, Fig. 3 is a schematic cross-sectional view of Fig. 2, and Fig. 4 is a ratio of stepped portions and noise. FIG. 5 is a partially omitted sectional view showing another embodiment of the present invention, and FIG. 6 is a diagram showing the relationship between wind speed and lift fluctuation. 1.2.3: Element wire, 10a, 10b, 10c. 10d: Stepped portion. 8- Party 1 Figure 03 2' Elder brother 2 figure Koωq\4q edict (971> 11~1 Linn)

Claims (1)

[Claims] (1) At least the outermost stranded wire layer of the stranded wire is composed of segment wires, a symmetrical step surface is formed on the outer peripheral surface thereof, and a step portion is further formed on the higher side of the step surface. Low-noise, low-vibration electric wire. (a) At least the outermost stranded wire layer of the stranded wire is composed of segment wires, a symmetrical step surface is formed on the outer peripheral surface, and a step portion is further formed on the higher side of the step surface, and the lower Low noise and low vibration such that t2/l+≧0.5, where the step difference between the step surface and the higher step surface is 11, and the height of the step portion formed on the higher step surface is also t2. Electrical wire.