JP2015211024A - Overhead transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an overhead transmission line in which corona ham noise is reduced without deteriorating low wind noise characteristic.SOLUTION: An overhead transmission line includes: center wires made of steel; a core in which seven aluminum-covered steel wires, which are formed by covering aluminum onto the center wires, are stranded; a plurality of first aluminum wires which are stranded around the core and have a circular cross section; two pairs of wires for low-wind-noise structure which are stranded around the plurality of first wires and construct a low wind noise structure; and a plurality of second wires which are stranded around the plurality of first wires together with the two pairs of wires for low-wind-noise structure, and arrayed around the plurality of first wires together with the two pairs of wires for low-wind-noise structure such that the two pairs of wires for low-wind-noise structure are arranged at a position symmetric with respect to a central axis.

Description

  The present invention relates to an overhead power transmission line.

  Conventionally, it is composed of a steel core part of an aluminum-coated steel wire and a conductor part of an inner layer and an outermost layer in which a plurality of segment-shaped aluminum strands are spirally twisted on the outer periphery of the steel core part. The outermost layer of the portion is formed of a protruding portion and a smooth portion protruding outward, the protruding portion is formed by two adjacent strands, and has a groove portion between the protruding portions, and the protruding portion is formed on the outermost layer. It is assumed that only one place is provided, the corner of the wire of the smooth portion is formed round, the radius of curvature R is 1.5 to 2.3 mm, and the conductor portion is formed by atyping all of the inner layer and the outermost layer. The number of strands in the outermost layer is 9 to 12, the projection height h from the outer peripheral surface of the strand of the smooth portion is 1 to 2 mm, and the groove depth of the groove The length d is 2 to 3 mm, and the opening angle α of the groove is 12 ° to 20 °. In addition, the surface of the conductor portion is subjected to hydrophilic treatment, and thus has various characteristics such as low wind noise, low corona noise, low wind pressure load, low loss, and corrosion resistance. There is an overhead power transmission line (see, for example, FIG. 1 of Patent Document 1).

JP 2012-256454 A

  By the way, in order to reduce the wind pressure of the overhead power transmission line, it is advantageous to reduce the outer diameter of the electric wire, and therefore, a deformed element wire having a substantially fan-shaped cross section is used as the inner layer and the outer layer of the conductor portion.

  However, depending on the application, when the outer diameter of the electric wire is reduced, corona noise, particularly corona hum noise due to a specific frequency, tends to increase. The corona hum sound represents a noise level due to a frequency component twice the power frequency.

  Then, it aims at providing the overhead power transmission line which aimed at reduction of a corona hum sound, without impairing a low wind noise characteristic.

  An overhead power transmission line according to an embodiment of the present invention includes a steel center line, a core obtained by twisting seven aluminum-covered steel wires coated with aluminum on the center line, and a cross-section that is twisted around the core. A plurality of first aluminum strands made of aluminum and two pairs of low wind noise structure strands twisted around the plurality of first strands to construct a low wind noise structure, and the two pairs And a plurality of second strands twisted around the plurality of first strands together with the two pairs of the wind noise-reducing structural strands, A plurality of second strands arranged around the plurality of first strands together with the two pairs of low wind noise structure strands so as to be arranged at symmetrical positions.

  It is possible to provide an overhead power transmission line that reduces corona hum noise without impairing low wind noise characteristics.

It is a perspective view which shows the overhead power transmission line 100 of embodiment. It is sectional drawing which shows the overhead power transmission line 100 of embodiment. It is a figure which shows the characteristic with respect to the electric wire surface maximum electric potential gradient (Gmax [kv / cm]) of the corona hum sound at the time of an equivalent light rain. It is a figure which shows the cross-sectional structure of the overhead power transmission line 10 for a comparison.

  Embodiments to which the overhead power transmission line of the present invention is applied will be described below.

<Embodiment>
FIG. 1 is a perspective view showing an overhead power transmission line 100 according to the embodiment. FIG. 2 is a cross-sectional view showing the overhead power transmission line 100 according to the embodiment. In the following, exemplary dimensions of each part are shown, but each dimension is only an example, and can be appropriately changed according to the application, the environment to be used, and the like.

  The overhead power transmission line 100 includes a core 110, a conductor 120, and a conductor 130. FIG. 1 shows a state in which the conductor 120 is removed stepwise from the core 110 in order to make the configuration of the overhead power transmission line 100 easier to understand.

  The core 110 has a configuration in which seven aluminum-clad steel wires 111 are twisted together. The seven aluminum-covered steel wires 111 all have the same configuration, and are produced by twisting six aluminum-covered steel wires 111 around one aluminum-covered steel wire 111 located at the center. .

  The aluminum-covered steel wire 111 has a center line 112 and a covering portion 113, and has a configuration in which the outer periphery of the center line 112 is covered with the covering portion 113 along the longitudinal direction. The center line 112 is made of steel, and the covering portion 113 is made of aluminum. The diameter of the aluminum-clad steel wire 111 is 2.5 mm to 3.1 mm, and preferably 2.64 mm.

  The conductor 120 includes a strand 121 that covers the outer periphery of the core 110 and a strand 122 that covers the periphery of the strand 121. The strands 121 and 122 are examples of first strands.

  The strands 121 and 122 have the same configuration, are circular in cross section, and are strands made of hard aluminum. The wires 121 and 122 are not limited to hard aluminum wires, but may be heat-resistant aluminum alloy wires or the like.

  The number of strands 121 is 8 to 10 (9 is preferred), and the number of strands 122 is 13 to 18 (preferably 15). The strand 121 is twisted around the outer periphery of the core 110 without a gap. Each strand 121 is wound around the outer periphery of the core 110 in a spiral shape in the opposite direction to the six 111 of the core 110, and 8 to 10 (9 is preferable) strands 121 of the core 110 are formed. The outer periphery is covered without any gaps.

  Moreover, the strand 122 is twisted around the outer periphery of 8 to 10 strands (preferably 9 strands) without a gap. Each strand 122 is wound around the outer periphery of the strand 121 in a spiral shape in the opposite direction to the strand 121. 13 to 18 (preferably 15) strands 122 cover the outer periphery of the strand 121 without any gaps.

  Double strands of hard aluminum are twisted around the outer periphery of the core 110 by the strands 121 and 122. The strand 121 has a diameter of 3.4 mm to 4 mm (preferably 3.96 mm), and the strand 122 has a diameter of 3.4 mm to 4.5 mm (preferably 3.96 mm).

  The conductor 130 covers the outer periphery of 13 to 18 strands (preferably 15 strands) 122, and has a low wind noise structure strand 131, a low corona noise reduction structure strand 132, and other strands 133. Have There are four strands 131 for low wind noise structure, two strands 132 for low corona noise reduction structure, and ten strands 133. The strand 133 is an example of a second strand.

  The reason for the four low-wind sound structure wires 131 is to reduce wind noise and corona noise, and two (a pair) are insufficient to reduce both characteristics. is there. The four (two pairs) are necessary in order not to impair the wind noise characteristics, and from the viewpoint of the electric potential gradient of the electric wire surface, the electric field is locally generated in the protrusions of the low wind noise structure strand 131. Although there are four (two pairs) in a disadvantageous direction, water drainage is improved and water droplets are less likely to adhere, so that corona noise is reduced.

  The low wind noise structure wire 131 is made of hard aluminum and has a substantially fan-shaped cross section. The low wind noise structure wire 131 is provided to construct a low wind noise structure for suppressing wind noise generated from the overhead power transmission line 100. The radial direction thickness is made thicker than the strand 133. For this reason, the low wind noise structure element wire 131 protrudes radially outward from the low corona noise reduction structure element wire 132 and the other element wires 133.

  The four low wind noise structure wires 131 are in pairs, and the low corona noise structure wires 132 are arranged between each pair.

  The low wind noise structure strand 131 is 2 mm thicker in the radial direction than the strand 133. For this reason, the low wind noise structure element wire 131 is 2 mm higher than the element wire 133. The radius of curvature r1 of the corners of the low wind noise structure element wire 131 is 1.0 mm or more and 2 mm or less, and preferably 1.8 mm. The radius of curvature r2 is 0.5 mm or more and 1.5 mm or less and preferably 1.1 mm. The curvature radius r1 is the curvature radius of the corner portion located on the strand 133 side, and the curvature radius r2 is the curvature radius of the corner portion located on the low corona noise reduction structure strand 132 side.

  The low corona noise-reducing structural element wire 132 is made of hard aluminum and has a semicircular cross-sectional shape. The low corona noise reduction structure strand 132 is disposed between the two low wind noise reduction structure strands 131. The radial thickness of the low corona noise reduction structure strand 132 is about ½ of the low wind noise structure strand 131. The low corona noise reduction structure strand 132 constructs a low corona noise reduction structure together with the two low wind noise reduction structure strands 131 located on both sides. The radius of curvature r3 of the corners of the low corona noise reducing structure wire 132 is 1.5 mm to 2 mm, preferably 1.8 mm.

  The low corona noise reduction structure wire 132 is provided between the pair of low wind noise structure wires 131 to provide a recess. When a water droplet protrudes from the surface of the electric wire due to water droplet adhesion, a corona discharge ( This is because corona noise) is likely to occur, and the corona noise is reduced by the corona noise-reducing structure strand 132 to suppress the protrusion of water droplets.

  The strand 133 is made of hard aluminum and has a substantially fan-shaped cross section. The radial thickness of the low corona noise reduction structure strand 132 is about ½ of the low wind noise structure strand 131. The strands 133 are arranged in two sets of five each, and have a substantially fan-shaped cross-sectional shape as if the ring was divided in the circumferential direction. For this reason, the outer periphery of the five strands 133 arranged continuously in the circumferential direction constructs a substantially continuous circumference.

  The radius of curvature r4 of the corner of the strand 133 is 0.5 mm. In addition, it is preferable that the curvature radius r4 is 0.5 mm or less because the outer surfaces of the ten strands 133 become substantially continuous.

  In the conductor 130 as described above, a set of two low-winding sound-generating structural wires 131 and one low-corona noise-generating structural wire 132 for the low-corona noise-generating structure is formed with respect to the central axis. Five strands 133 are arranged between a pair of two low-winding sound-generating structural elements 131 and one low-corona noise-generating structural element 132, which are arranged at point-symmetric positions. Is arranged.

  The strand 133 and the low-corona noise structure wire 132 constitute a low-noise (low wind noise + low corona noise) structure wire.

  The four low wind noise structure wires 131, the two low corona noise reduction structure wires 132, and the ten strands 133 are arranged on the circumference in the order described above. The strand 122 is spirally wound around the outer periphery of the strand 122 in the opposite direction to the strand 122 so as to cover the outer periphery of the 13 to 18 strands (preferably 15 strands) without gaps.

  Further, the wire outer diameter φ1 of the portion of the strand 133 of the overhead power transmission line 100 as described above is 29.05 mm, and the wire outer diameter φ2 of the portion of the low wind noise structure strand 131 is 33.05 mm. It is. Note that the surface of the overhead power transmission line 100 (the surface of the conductor 130) is subjected to hydrophilic treatment.

  Next, characteristics of the corona hum sound with respect to the maximum potential gradient (Gmax [kv / cm]) of the wire surface during equivalent light rain will be described.

  FIG. 3 is a diagram showing the characteristics of the corona hum sound with respect to the maximum potential gradient (Gmax [kv / cm]) of the wire surface during equivalent light rain.

  Equivalent light rain simulates the situation where the wire is exposed to a level equivalent to that of natural light rain (approximately 0.5 mm / h). Equivalent light rain conditions are used.

  Moreover, in FIG. 3, the measurement result by the overhead transmission line for a comparison is shown. An overhead power transmission line 10A for comparison shown in FIG. 4A has a configuration in which conductors 20A and 30A are twisted around a core 110A. The diameter of the seven aluminum covered steel wires included in the core 110A is 2.7 mm. The conductor 20A has eight strands having a substantially fan-shaped cross section. The conductor 30A has the same configuration as the conductor 130 of the overhead power transmission line 100 of the embodiment. As shown in FIG. 4A, the conductors 20A and 30A have a cross-sectional shape such that the conductors 20A and 30A are in close contact with each other with almost no gap.

The cross-sectional area of the conductor portion of the overhead power transmission line 10A is about 520 mm ² , the wire outer diameter similar to the wire outer diameter φ1 of the overhead power transmission line 100 of the embodiment is 27.1 mm, and the low wind noise structure The wire outer diameter (similar to φ2) of the portion of the element wire is 31.5 mm. In addition, the total value of the cross-sectional areas of all the strands included in the conductors 20A and 30A is the strands 121 and 122 included in the conductors 120 and 130 of the overhead power transmission line 100 of the embodiment, and the low wind noise structure element. It is equal to the total value of all cross-sectional areas of the wire 131, the low corona noise reduction structure wire 132, and the wire 133.

Sectional area of the conductor portion of the overhead transmission line 10B for comparison shown in FIG. 4 (B) is about 410 mm ^2, around the core 110B, has a configuration in which twisting conductor 20B. The diameters of the seven aluminum-clad steel wires included in the core 110B are 3.5 mm. The conductor 20B has 10 strands on the inside and 16 strands on the outside, and the diameter of the 26 strands is 4.5 mm. The electric wire outer diameter of the overhead power transmission line 10B is 28.5 mm.

The cross-sectional area of the conductor portion of the comparative overhead transmission line 10C shown in FIG. 4C is about 410 mm ² , and has a configuration in which the conductors 20C and 30C are twisted around the core 110C. The diameters of the seven aluminum-clad steel wires included in the core 110C are 3.5 mm. The conductor 20C has ten strands whose section is substantially fan-shaped. The conductor 30 </ b> C has a low wind noise structure similar to the conductor 130 of the overhead power transmission line 100 of the embodiment, but portions other than the low wind noise structure wire are circular wires. In the overhead power transmission line 10C, the wire outer diameter similar to the wire outer diameter φ1 of the overhead power transmission line 100 of the embodiment is 26.3 mm, and the wire outer diameter (φ2 Similarly) is 30.7 mm.

  The comparative overhead power transmission line 10D shown in FIG. 4D has a configuration in which a conductor 20D is twisted around a core 110D. The diameter of the seven aluminum covered steel wires included in the core 110D is 3.5 mm. The conductor 20D has 10 strands on the inside and 16 strands on the outside, and the diameter of the 26 strands is 4.5 mm. The electric wire outer diameter of the overhead power transmission line 10D is 28.5 mm. Further, in the overhead power transmission line 10D, two SP rods (spiral rods) 30D for wind noise suppression are spirally wound around the 16 strands. The diameter of the SP rod 30D is 6.0 mm.

Conventionally, an overhead power transmission line 10C exists as a low noise (low wind noise + low corona noise wire) wire of the overhead power transmission line 10B. The overhead power transmission lines 10B and 10C have the same wire weight and equivalent wind pressure outer diameter. However, this wire, the low noise cable of the standard 410 mm ² equivalent, in some cases corona noise characteristic is often insufficient.

  Originally, as a countermeasure against wind noise of the overhead power transmission line 10B, a countermeasure for mounting the SP rod 30D like the overhead power transmission line 10D is implemented. Therefore, in the present embodiment, a new condition that the weight of the electric wire is equivalent to 10D equipped with the SP rod is provided, and the electric wire with low corona noise that satisfies this condition and does not impair the low wind noise characteristics is used for the overhead power transmission line 100. It is.

  By the way, the comparative overhead transmission line 10B is a standard electric wire of this size, 10C is a conventional low noise electric wire of the same size as 10B, and the overhead transmission line 10A is a process leading to the development of the overhead transmission line 100. Prototype and development.

  As shown in FIG. 3, in the overhead power transmission line 100 according to the embodiment, the characteristic of the corona hum sound with respect to the maximum potential gradient (Gmax (kV / cm)) of the corona hum sound at the time of equivalent light rain is about 35 dBA at 15 kV / cm, It is about 38 dBA at 16 kV / cm, about 42 dBA at 17 kV / cm, and about 48 dBA at 18 kV / cm.

  On the other hand, in the comparative overhead transmission line 10A, it is about 34 dBA at 15 kV / cm, about 39 dBA at 16 kV / cm, about 46 dBA at 17 kV / cm, and about 51 dBA at 18 kV / cm.

  Further, in the comparative overhead power transmission line 10B, it is about 35 dBA at 15 kV / cm and about 43 dBA at 16 kV / cm.

  Further, in the comparative overhead power transmission line 10C, it is about 46 dBA at 15 kV / cm, about 50 dBA at 16 kV / cm, about 53 dBA at 17 kV / cm, and about 54 dBA at 18 kV / cm.

  Thus, in the overhead power transmission line 100 of the embodiment, characteristics of 35 dBA or less at 15 kV / cm, 38 dBA or less at 16 kV / cm, 42 dBA or less at 17 kV / cm, and 48 dBA or less at 18 kV / cm are obtained. Is also improved compared to the comparative overhead power transmission line 10A.

  As the electric wire outer diameter increases in this manner, the potential gradient on the surface of the overhead power transmission line 100 is smaller than that of the comparative power transmission line 10A, and thus the corona hum noise is considered to be reduced. In addition, the overhead power transmission line 100 of the embodiment has significantly reduced corona hum noise compared to the overhead power transmission lines 10B and 10C for comparison.

  Since the overhead power transmission lines 10B and 10C are composed of all outermost strands or partially circular strands, the circular strands act as protrusions, and the potential gradient tends to increase locally. On the other hand, the overhead power transmission line 100 uses a fan-shaped element wire (elementary wire 133) on the surface of the electric wire, so that the potential gradient does not increase locally, and is an advantageous structure from the viewpoint of the electric field strength on the surface. .

  Moreover, since the overhead power transmission line 100 uses a fan-shaped element wire (element wire 133) as an outer layer element wire, water droplets adhering to the surface of the electric wire are likely to slip vertically downward when it rains, and this is a low wind noise structure. By colliding with the protruding portion of the element wire 131, the water droplet is easily cut. That is, the structure is excellent in water drainage and has a structure in which corona discharge (noise) due to water droplets hardly occurs.

  As described above, according to the embodiment, it is possible to provide the overhead power transmission line 100 in which the corona hum noise is reduced.

  Moreover, since the diameter of the aluminum-clad steel wire 111 is made thinner than the overhead power transmission line 10A for comparison, the overhead power transmission line 100 of the embodiment reduces the amount of steel of the core wire 112 and is reduced in weight.

  The outermost layer strand is a sector strand from the viewpoint of the above-described potential gradient relaxation and drainage. However, when a fan-shaped element wire is used, it does not have a gap as compared with a circular element wire, so that it occupies some space and tends to be heavy. Accordingly, the aluminum-covered steel wire 111 is thinned to the extent that it can be pulled out, and a fan-shaped strand (elementary wire 133) having a high occupation ratio can be applied to the outermost layer by the lightening.

  In the case where two round strands such as the strands 121 and 122 are arranged in the donut-like cross-sectional area between the diameter of the layer where the core 122 is arranged excluding the outermost strand and the diameter of the core, aluminum is used. If the diameter of the covered steel wire 111 is reduced, the weight of the electric wire can be reduced even if the diameters of the circular strands (the strands 121 and 122) are increased.

  The overhead power transmission line 100 of the embodiment is equivalent to the overhead power transmission line 10B and the wire strength (minimum tensile load), with the constraint that the power weight of the overhead power transmission line 10D wound with two SP rods 30D is equal or less, It is a low noise wire with the best corona characteristics without impairing wind noise characteristics.

  As the electric wire size is increased and the outer diameter of the electric wire is increased, the potential gradient on the surface of the electric wire is relieved, as is well known, and the weight increases as the size increases. In addition, if a hard aluminum wire is used instead of an aluminum-covered steel wire for the core, the lighter and the outer diameter of the aluminum conductor part (the outer diameter of the electric wire) can be further increased, but this is insufficient in strength. . Therefore, the overhead power transmission line 100 is a low-noise electric wire that has the best wind noise and corona noise characteristics while satisfying the above-described constraints.

  The overhead power transmission line of the exemplary embodiment of the present invention has been described above, but the present invention is not limited to the specifically disclosed embodiment, and does not depart from the scope of the claims. Various modifications and changes are possible.

DESCRIPTION OF SYMBOLS 100 Overhead power transmission line 110 Core 111 Aluminum covered steel wire 112 Core wire 113 Covering part 120 Conductor 121 Elementary wire 122 Elementary wire 130 Conductor 131 Low wind noise structure element wire 132 Low corona noise reduction structure element wire 133 Elementary wire

Claims (5)

A steel center line and a core formed by twisting seven aluminum-covered steel wires coated with aluminum on the center line;
A plurality of first strands made of aluminum, twisted around the core and having a circular cross section;
Two pairs of low wind noise structure strands twisted around the plurality of first strands to construct a low wind noise structure;
A plurality of second strands twisted around the plurality of first strands together with the two pairs of low wind noise construction strands, wherein the two pairs of wind noise construction strands are centered A plurality of second strands arranged around the plurality of first strands together with the two pairs of low wind noise structure strands so as to be arranged at positions symmetrical with respect to an axis. , Overhead power lines.   The characteristic of the corona hum sound with respect to the maximum electric potential gradient of the electric wire surface during equivalent light rain is 35 dBA or less at 15 kV / cm, 38 dBA or less at 16 kV / cm, 42 dBA or less at 17 kV / cm, and 48 dBA or less at 18 kV / cm. The overhead power transmission line according to 1.   The overhead power transmission line according to claim 1 or 2, wherein the first strand is double-twisted around the core.   The overhead power transmission line according to any one of claims 1 to 3, wherein a diameter of the aluminum-covered steel wire is 2.5 mm to 3.1 mm.   The overhead power transmission line according to any one of claims 1 to 4, wherein a diameter of the first strand is 3.4 mm to 4.5 mm.

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