JP2000243143A - Overhead electric wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase power transmission capacity and improve low wind noise characteristic and hard snow accretion characteristic by stranding wires formed with a plurality of projecting stripes of respective fixed height on the outer circumference of a cable core constituted by stranding metallic conductors on the outermost circumferential layer so as to direct the projecting stripes outward. SOLUTION: On the outermost layer of a cable core stranding metallic conductors 2 such as aluminum or aluminum alloy wire on the outer circumference of a steel stranded wire 1, and six wires 10 formed with two projecting stripes of hight (h) on each are stranded. The wires 10 are stranded so that the projecting stripe 11a rounded on the extreme end is directed outward, and a groove part 11b between the projecting stripes 11a is also rounded to smoothen the flow of wind. Further two pieces of wire 10 provided with one or two projecting stripe higher than the height (h) of the projecting stripe 11a of the wire 10 of the outermost layer are replacingly arranged upper and lower symmetrically. Hereby heat release characteristic is improved, wind noise prevention effect is enlarged, and a snow accretion quantity is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overhead electric wire having improved heat radiation characteristics, low noise characteristics, and snow-resistant characteristics.

[0002]

2. Description of the Related Art Various characteristics are required for overhead electric wires, and among them, an increase in power transmission capacity, an improvement in low wind noise characteristics, an improvement in snow resistance, and the like are important requirements.

[0003] Overhead electric wires generate heat due to conductor resistance at the time of power transmission. If the transmission current is too large, the conductors of the overhead electric wires are kept in a heated state for a long time, and the conductor strength is reduced. Is limited. As a general overhead electric wire, as shown in FIG. 8, the outermost layer of a cable core in which a conductive strand 2 having a circular cross section is twisted around the steel strand 1 around the steel strand 1 is usually provided with a trapezoidal cross section. A smooth body type overhead electric wire in which the outer peripheral surface is smooth, in which the wires 20 are twisted, is used. However, since this type of overhead electric wire has a smooth outermost layer and a small surface area, the wind pressure resistance is small, but there is a certain limit to the dissipation of conductor heat generated during power transmission. Therefore, it is not possible to reduce the conductor temperature and increase the power transmission capacity by increasing the heat dissipation during power transmission.

In order to improve low wind noise characteristics, Karman vortices generated on the leeward side of overhead electric wires, which cause wind noise, are disturbed as shown in FIG. An overhead electric wire having a structure in which a continuous groove 22 is provided in the longitudinal direction between the strands 21 is used, or a part of the segment strand 20 of the outermost layer as shown in FIG.
Are arranged in parallel and twisted to form a ridge 24
An overhead electric wire having a structure in which a continuous groove 25 is formed between a and 24b is used. However, the former (the overhead electric wire shown in FIG. 9) has a limit in the low wind noise effect because the grooves 22 in the outermost layer are uniformly arranged in the circumferential direction, and the latter (shown in FIG. 10). The overhead wire is superior to the former in the low wind noise effect, but has a disadvantage that the heat dissipation is equal to that of the smooth body overhead wire because most of the outermost layer is smooth.

As shown in FIG. 11, an overhead electric wire having a structure shown in FIG. 11 in which a wire 26 having a ridge 27 formed on a part of the outermost layer of an overhead electric wire is twisted as shown in FIG. Is used to prevent snow from accumulating. However, in this type of overhead electric wire, when the amount of snowfall is large and the amount of snow attached to the overhead electric wire is extremely large, the snow gets over the ridges 27 on the outermost periphery of the overhead electric wire, and develops into a snowy snow. is there.

[0006]

As described above, as described above, an increase in the transmission capacity required for an overhead electric wire, an improvement in low wind noise characteristics,
Various measures have been taken to improve the hard-to-wear property, but none of these requirements are sufficient yet, and further improvements are required.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to an outer periphery of an overhead electric wire in order to increase the transmission capacity required for the overhead electric wire, to improve low wind noise characteristics, and to improve snow-resistant characteristics. It is intended to solve the problem by giving a new creation to the shape of the layer, the configuration, structure,
As for the material of the strand, a conventionally used one is used as it is.

[0008] The overhead electric wire according to claim 1 of the present invention is characterized in that a wire having a plurality of ridges having a height h formed on the outer periphery of a cable core formed by twisting metal conductors, is formed such that the ridges are outward. This is an overhead electric wire characterized by being twisted to the outermost layer so as to face, and to improve the heat radiation characteristics of the overhead electric wire and improve the power transmission capacity.

In the overhead electric wire according to a second aspect of the present invention, a wire formed with a plurality of ridges having a height h is twisted to the outermost layer with the ridges directed outward. In the overhead electric wire according to No. 1, one or more outermost strands are placed on a strand formed with a plurality of ridges having a height H higher than the height h of the ridges of the other outermost strands. An overhead electric wire characterized by being replaced, which also improves low wind noise characteristics.

An overhead electric wire according to a third aspect of the present invention is the overhead electric wire according to the first aspect, wherein a strand formed with a plurality of ridges is twisted to an outermost layer so that the ridges face outward. In the electric wire, the ridge is formed by twisting two strands having the same height h and the ridge having a strand formed with two ridges having different heights h and H. An overhead electric wire characterized by:
It is intended to improve the hard-to-wear property.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of an overhead electric wire having improved heat radiation characteristics according to claim 1 of the present invention. A strand 1 in which two ridges 11a with a height h are formed on the outermost layer of a cable core in which a metal conductor 2 such as aluminum or an aluminum alloy wire is twisted around the outer periphery of a steel strand 1
FIG. 2 is a cross-sectional view of an overhead electric wire obtained by twisting No. 0 so that a ridge 11a faces outward. In addition, as shown in FIG. 2, the shape of the strand is a ridge 1 in which the tip (top) of the ridge of the strand 12 is sharpened.
3a, but the tip is rounded like the ridge 11a of the strand 10 in FIG. 1, and the groove 11b between the ridges 11a is formed.
Also, it is preferable to have a round shape because the flow of the wind is smooth.

FIG. 5 shows the conventional smooth body type overhead electric wire shown in FIG. 8 and an overhead conductor according to the present invention shown in FIG. 1 in which the surface area of the outermost layer is 1.5 times the equivalent conductor cross-sectional area. This is a comparison between the results of an electric current test of an electric wire and the results. It is apparent from FIG. 5 that the temperature rise during energization of the overhead electric wire having the structure of the present invention can be suppressed to about 20% lower than that of the conventional type. Therefore, when the overhead electric wire of the present invention is used, a rise in conductor temperature can be suppressed, so that the transmission capacity can be increased as compared with the conventional overhead electric wire.

FIG. 3 is a sectional view of an overhead electric wire showing an embodiment of an overhead electric wire with improved low wind noise characteristics according to a second aspect of the present invention. The overhead electric wire having the improved low wind noise characteristic shown in FIG. 3 is higher than the wire 16 having the convex portion having the height h formed in the outermost layer in the overhead electric wire shown in FIG. The strand 14 on which the protruding strip 15a having the height H is formed is twisted such that the strand 14 is located at a target position. In FIG. 3, a ridge 15 having a height H twisted to the outermost layer is shown.
Although the number of the wires 14 forming the a is set to two and arranged at the target position, even if the number of the wires 14 is one or more than two, the generation of Karman vortices on the leeward side is generated. Therefore, it is effective in improving low wind noise characteristics. It is preferable that the tip of the ridge 15a and the groove 15b between the ridges 15a be rounded because the flow of the wind is smooth.

FIG. 6 shows a low wind noise overhead electric wire of a type in which a wide groove is provided between the wires of the outermost layer of the conventional smooth body type overhead electric wire shown in FIG. It is equivalent and compares the low wind noise characteristic with the overhead electric wire according to the present invention shown in FIG. FIG. 6 shows the results of a wind noise test showing the relationship between the magnitude of the average wind speed for 10 minutes and the wind noise level. The wind noise prevention effect of the overhead electric wire having the structure of the present invention is the same as that of the conventional wind noise overhead electric wire. 20 to 30% larger than the above.

FIG. 4 is a cross-sectional view showing one embodiment of an overhead electric wire having improved snow resistance according to claim 3 of the present invention. The overhead electric wire with improved snow resistance shown in FIG. 4 is different from the overhead electric wire shown in FIG. 3 in that the height of the two ridges having a height H twisted to the outermost layer is h and H. It was different. That is, the height of one of the two ridges having a high height H is the same as the height h of the ridge of the other strand 19,
The height of the other ridge is kept at H, and the height of the ridge 1 is H.
8a and a wire 17 on which a ridge 18c having a height h is formed are arranged at target positions in the diameter direction of the outermost layer, and the wires 19 arranged on other outermost layers are ridges having a height h. This is an overhead electric wire.

The height between the ridges H and h is １ ／.
It is preferable to have a relationship of ≦ h / H ≦ 4/5. The reason for giving a relationship of 1/2 ≦ h / H ≦ 4/5 between H and h is that if h / H <１ ／, it is equivalent to a single high-height ridge. And h / H> 4/5, the height H is high.
This is because only the same shape effect as when two convex stripes are used can be obtained. Either way, the hard-to-wear property will decrease,
Particularly in heavy snowfall, the hard-to-wear property is significantly reduced.

FIG. 7 shows a conventional snow-resistant overhead overhead electric wire shown in FIG. 11 in which a strand 26 having a ridge 27 is twisted only in a part of the outermost layer, and a conductor cross-sectional area equivalent to that. FIG. 5 is a comparison of the hard-to-snow characteristics of an overhead electric wire with improved hard-to-snow shown in FIG. 4 according to the present invention. From FIG. 7, it can be seen that the snowfall amount of the hard-to-snow overhead electric wire according to the present invention shown in FIG. This effect is due to the fact that the stepped ridges are provided close to the outermost layer of the overhead electric wire, so there is a time lag before each ridge is buried by snow accretion. It is thought to be caused by the difficulty of occurrence.

[0019]

By using the overhead electric wire according to the first aspect of the present invention, it is possible to increase the power transmission capacity based on the improvement of the heat dissipation characteristics. Further, the use of the overhead electric wire according to claim 2 of the present invention can improve low wind noise characteristics.
If the overhead electric wire according to the third aspect of the present invention is used, it is possible to improve snow-resistant characteristics. These effects can also be expected to have superimposed effects. That is, the use of the overhead electric wire according to claim 2 of the present invention can improve not only low wind noise characteristics but also heat dissipation characteristics and increase power transmission capacity. Further, the use of the overhead electric wire according to the third aspect of the present invention can further improve the snow-repelling resistance.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an overhead electric wire according to the first invention.

FIG. 2 is a cross-sectional view showing another embodiment of the overhead electric wire according to the first invention.

FIG. 3 is a sectional view showing an embodiment of an overhead electric wire according to the second invention.

FIG. 4 is a sectional view showing an embodiment of an overhead electric wire according to the third invention.

5 is a comparison diagram of the results of a conduction test of an overhead electric wire having the structure of FIG. 1 according to the present invention and an overhead electric wire having the conventional structure (FIG. 8).

6 is a comparison diagram of wind noise level test results between the overhead electric wire having the structure of FIG. 3 according to the present invention and an overhead electric wire having the conventional structure (FIG. 9).

FIG. 7 is a comparison diagram of the results of a snow accretion test of the overhead electric wire having the structure of FIG. 4 according to the present invention and the conventional electric wire (FIG. 11).

FIG. 8 is a cross-sectional view of a conventional smooth body type overhead electric wire.

FIG. 9 is a sectional view of a conventional low wind noise type overhead electric wire (part 1).

FIG. 10 is a sectional view of a conventional low wind noise type overhead electric wire (part 2).

FIG. 11 is a cross-sectional view of a conventional snow-resistant overhead electric wire that is difficult to reach.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel twisted wire 2 Aluminum or aluminum alloy wire 10 Elemental wire which formed the convexity 11a convexity 11b groove 12 Elemental wire which formed the convexity 13a convexity 13b groove 14 Elemental wire which formed the convexity 15a convexity 15b groove 16 Other strands 17 Stranded strands 18a High ridges 18b Grooves 18c Low ridges 19 Other strands 20 Cross-section trapezoidal strands 21 Stranded strands 22 Grooves 23 Stranded strands 24a convex ridge a 24b convex ridge b 25 groove 26 element wire having convex ridge 27 convex ridge

Claims (3)

[Claims] 1. A strand formed by forming a plurality of ridges having a height h on the outer periphery of a cable core formed by twisting metal conductors, and twisting the outermost layer so that the ridges face outward. An overhead electric wire, characterized in that: 2. The overhead electric wire according to claim 1, wherein the wire formed with a plurality of ridges having a height h is twisted around the outermost layer so that the ridges face outward. An overhead electric wire, wherein one or more wires are replaced by a wire formed with a plurality of ridges having a height H higher than the height h of the ridges of the other outermost strands. 3. The overhead electric wire according to claim 1, wherein a wire formed with a plurality of ridges having a height h is twisted to an outermost layer so that the ridges face outward. Are two strands having the same height h, and two of the heights h and H where the ridges are different.
An overhead electric wire characterized by twisting a strand formed with a ridge.