JP2016004604A - Transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission line reduced in wind noise, wind pressure load, and corona noise in the case of providing at least three external strand layers.SOLUTION: A transmission line includes a steel core part, and at least three external strand layers provided by twisting a plurality of element wires outside the steel core part. A radial direction height from the outer peripheral surface of a smooth part element wire each of a first projection element wire and a second projection element wire is 1.9 mm-2.4 mm. A corner part of the outer peripheral side of each of the plurality of smooth part element wires is formed in a circular form. A curvature radius of the corner part of the outer peripheral side of the smooth part element wire is 1.3 mm-1.7 mm. A depth in the radial direction from the outer peripheral surface each of the first projection element wire and the second projection element wire to the outer peripheral surface of a groove part element wire is 1.8 mm-2.3 mm. Only one pair each of the first projection element wires, the second projection element wires, and the groove part element wires are provided on an outermost external strand wire layer, and the number of a plurality of element wires forming the outermost external strand wire layer is 16-20.

Description

  The present invention relates to a power transmission line.

  In recent years, overhead power transmission lines have been increased in size due to high pressure and are provided close to urban areas. Since wind noise is generated from the transmission line installed in the overhead power transmission line during strong winds, it is necessary to reduce the wind noise generated from the transmission line from the viewpoint of environmental harmony around the overhead power transmission line.

  Moreover, in an ultra-high voltage overhead power transmission line represented by a 500 kV overhead power transmission line, corona discharge is generated from water droplets formed on the surface of the power transmission line at the time of rain. It is necessary to take measures against a corona ham sound having a frequency component twice the power supply frequency.

  Furthermore, it is important to reduce the wind pressure load (wind pressure) applied to the transmission lines in order to withstand the typhoons that have become large due to recent global warming. In recent years, there has been an upgrade of equipment that replaces only aluminum transmission lines that have deteriorated over time due to the support (transmission towers, etc.) that support the transmission lines, and the transmission lines are reduced when the equipment is updated. Making the wind pressure an effective measure is also an effective measure for giving a margin to the strength of the support that supports the transmission line.

  Here, for example, Patent Literature 1 is disclosed as a power transmission line in which wind noise, wind pressure load, and corona noise are reduced. In Patent Document 1, when two external stranded wire layers are provided, the radius of curvature of the corner of the smooth portion, the height of the protrusion from the outer peripheral surface of the smooth portion, the depth of the groove, the strand of the outermost layer The optimal numerical range such as the number of

JP 2012-256454 A

  An object of the present invention is to provide a power transmission line in which wind noise, wind pressure load, and corona noise are reduced when three or more external stranded wire layers are provided.

According to one aspect of the invention,
A steel core,
Three or more external stranded wire layers provided by twisting a plurality of strands on the outside of the steel core, and
Have
Outermost external stranded wire layer located on the outermost side among the three or more external stranded wire layers,
A plurality of smooth portion strands provided side by side along the circumferential direction;
A first protruding element wire and a second protruding element wire that are provided between two of the plurality of smooth portion strands and are provided higher in the radial direction than the smooth portion strand;
A groove element wire provided between the first protrusion element wire and the second protrusion element wire, and provided in a radial direction lower than the first protrusion element wire and the second protrusion element wire;
Have
The height in the radial direction from the outer peripheral surface of the smooth portion strand of each of the first protrusion strand and the second projection strand is 1.9 mm or more and 2.4 mm or less,
A corner portion on the outer peripheral side of each of the plurality of smooth portion strands is formed in an arc shape,
The radius of curvature of the corner portion on the outer peripheral side of the smooth portion strand is 1.3 mm or more and 1.7 mm or less,
The radial depth from the outer peripheral surface of each of the first protruding element wire and the second protruding element wire to the outer peripheral surface of the groove element wire is 1.8 mm or more and 2.3 mm or less,
The first projecting element wire, the second projecting element wire, and the groove element wire are provided in only one set in the outermost outer stranded wire layer,
A power transmission line in which the number of the plurality of strands constituting the outermost external stranded wire layer is 16 or more and 20 or less is provided.

According to another aspect of the invention,
A steel core,
Three or more external stranded wire layers provided by twisting a plurality of strands on the outside of the steel core, and
Have
Outermost external stranded wire layer located on the outermost side among the three or more external stranded wire layers,
A plurality of smooth portion strands provided side by side along the circumferential direction;
A first protruding element wire and a second protruding element wire that are provided between two of the plurality of smooth portion strands and are provided higher in the radial direction than the smooth portion strand;
A groove element wire provided between the first protrusion element wire and the second protrusion element wire, and provided in a radial direction lower than the first protrusion element wire and the second protrusion element wire;
Have
A power transmission line is provided in which a radial height from an outer peripheral surface of each of the smooth portion strands of the first protrusion strand and the second projection strand is 1.9 mm or more and 2.4 mm or less. The

  According to the present invention, when three or more external stranded wire layers are provided, a power transmission line in which wind noise, wind pressure load, and corona noise are reduced is provided.

It is sectional drawing orthogonal to the axial direction of the power transmission line which concerns on one Embodiment of this invention. It is a figure which shows the amount of wind noise reduction with respect to the height of the radial direction from the outer peripheral surface of each smooth part strand of a 1st protrusion strand, and a 2nd protrusion strand. It is a figure which shows the amount of wind pressure reduction with respect to the height of the radial direction from the outer peripheral surface of each smooth part strand of a 1st protrusion strand, and a 2nd protrusion strand. It is a figure which shows the wind pressure reduction amount with respect to the curvature radius of the corner | angular part of the radial direction outer side of a smooth part strand. It is a figure which shows the corona hum sound level with respect to the radial depth from each outer peripheral surface of a 1st protrusion strand, and a 2nd protrusion strand to the outer peripheral surface of a groove part strand. It is a figure which shows the wind pressure reduction amount with respect to the number of sets of a 1st protrusion strand, a 2nd protrusion strand, and a groove part strand. It is sectional drawing orthogonal to the axial direction of the power transmission line of Example 1. FIG. It is sectional drawing orthogonal to the axial direction of the power transmission line of Example 2. FIG. It is sectional drawing orthogonal to the axial direction of the power transmission line which concerns on a comparative example.

<Knowledge obtained by the inventors>
First, knowledge obtained by the inventors will be described.

  Here, as a comparative example, a power transmission line 90 described in Patent Document 1 will be described with reference to FIG. FIG. 9 is a cross-sectional view orthogonal to the axial direction of the power transmission line according to the comparative example.

  In the power transmission line 90 according to the comparative example, two external twisted wire layers (an inner layer 912 and an outermost layer 913) are provided. The outermost layer 913 includes a smooth portion strand 931 and protruding portion strands 930A and 930B. The protrusion strands 930A and 930B are provided with protrusions 932A and 932B, respectively. Grooves 933A and 933B are provided between the protrusions 932A and 932B of the protrusion strands 930A and 930B, and the groove portions 933A and 933B are continuously adjacent to each other to form a groove portion 913a.

In Patent Document 1 of the comparative example, in a power transmission line such as ACSR 410 mm ² (a steel core aluminum stranded wire having a nominal cross-sectional area of 410 mm ² ) provided with two external twisted wire layers, the radius of curvature of the corner portion of the smooth portion strand 931 is The optimum numerical ranges such as the height of the protrusions 932A and 932B from the outer peripheral surface of the smooth portion strand 931, the depth of the groove portion 913a, and the number of strands of the outermost layer 913 are defined. Accordingly, in Patent Document 1 of the comparative example, in transmission lines such as ACSR410mm ² external twisted wire layer are provided two layers, wind noise, it is to be able to reduce the wind load and audible noise.

Here, 500 kV transmission lines are adopted in the main trunk lines in Japan. Therefore, the power transmission line used is considered to be economical and the influence of typhoon, and the transmission line of ACSR 410 mm ² is often adopted. The ACSR 810 mm ² transmission line has a low surface potential of the transmission line and is unlikely to generate corona noise, but may increase the construction cost. In the case of the ACSR 330 mm ² transmission line, the surface potential of the transmission line is high. Noise levels can be high. For these reasons, as a result, a lot of ACSR 410 mm ² is adopted, and therefore, the invention described in Patent Document 1 according to the comparative example was made with a transmission line of this size as a target.

On the other hand, in recent years, not only the transmission line of ACSR410mm ^2, has become the large size of the transmission line (ACSR610mm ² or ACSR810mm ^2, etc.) and Ru update time re-covering than ACSR410mm ² has passed the construction after 40 years, ACSR410mm Development of technology for reducing wind noise, wind pressure load and corona noise in transmission lines larger than ² has been strongly desired.

However, the configuration of the power transmission line described in Patent Document 1 according to the comparative example was invented with a power transmission line of ACSR 410 mm ² provided with two external twisted wire layers as a target, and has a transmission size larger than that of ACSR 410 mm ^2. There is a possibility that the configuration of the transmission line according to the comparative example cannot be applied as it is to the electric wire.

For example, in the configuration of the power transmission line of Patent Document 1 of the comparative example, the groove portion 913a is formed by adjoining the groove portions 933A and 933B by two strands of the protruding portion wires 930A and 930B. Thus, projections 932A, the opening angle of 932B is in the predetermined angle theta _r. In a transmission line having a size larger than ACSR 410 mm ² , the opening angle θ _r of the protrusions 932A and 932B formed by only two of the protrusion strands 930A and 930B may be insufficient compared to the outer diameter of the transmission line. There is sex. Specifically, the opening angle theta _r, a degree less than 40 °. For this reason, the wind around the transmission line is not sufficiently disturbed, and wind noise may not be sufficiently reduced.

  Moreover, in patent document 1 of a comparative example, in the power transmission line provided with two external twisted wire layers, in order to reduce a wind noise, the height from the outer peripheral surface of the smooth part strand 931 of the protrusions 932A and 932B The optimal range is specified. However, in the power transmission line in which three or more external stranded wire layers are provided, even if the height from the outer peripheral surface of the smooth portion strand 931 of the protrusions 932A and 932B is set in the same range as in Patent Document 1 of the comparative example, wind noise is reduced. There may be cases where it cannot be reduced.

  Moreover, in patent document 1 of a comparative example, in the power transmission line in which two external twisted wire layers are provided, in order to reduce the wind pressure, the curvature radius of the corner portion on the outer peripheral side of the smooth portion strand 931, or the outermost layer 913 The optimum range of the number of strands is specified. However, in a power transmission line in which three or more external twisted wire layers are provided, the radius of curvature of the corner portion on the outer peripheral side of the smooth portion strand 931 and the number of strands of the outermost layer 913 are the same as those in Patent Document 1 of the comparative example. However, there is a possibility that the wind pressure load cannot be reduced.

  As a result of intensive studies, the present inventors have found a configuration that can solve the above problems in a power transmission line in which three or more external stranded wire layers are provided. The following embodiments are based on the above findings.

<One Embodiment of the Present Invention>
(1) Structure of power transmission line A power transmission line according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view orthogonal to the axial direction of the power transmission line 10 according to the present embodiment.

  The power transmission line 10 according to the present embodiment is configured to reduce wind noise, wind pressure load, and corona noise when three or more external stranded wire layers 200 are provided. Details will be described below.

  In the following, the “axial direction” of the transmission line 10 refers to the longitudinal direction of the transmission line 10, and the “radial direction” of the transmission line 10 refers to a direction perpendicular to the axial direction of the transmission line 10, that is, the transmission line 10. The short direction is referred to, and the “circumferential direction” of the power transmission line 10 refers to a direction along the outer periphery of the power transmission line 10. The “inner peripheral surface” refers to the surface on the steel core 100 side, and the “outer peripheral surface” refers to the surface opposite to the inner peripheral surface.

(Steel core)
As shown in FIG. 1, a steel core portion 100 that functions as a tension member that bears the tension of the power transmission line 10 during an overhead line is provided at the center of the power transmission line 10. The steel core 100 is provided extending in the axial direction. The steel core portion 100 is configured by twisting a plurality of core wires 110, for example, a first core wire provided in the center and a second twisted so as to cover the outer periphery of the first core wire. And a core wire. For example, six second core wires are provided, and are arranged symmetrically around the first core wire.

  The core wire 110 of the steel core portion 100 has a steel wire 112 at the center. The steel wire 112 is comprised by at least any one of a steel wire, an invar wire, and a carbon composite wire, for example. The “carbon composite wire” is formed by hardening a plurality of assembled carbon fibers (carbon fibers) with a resin. In the present embodiment, the core wire 110 is, for example, an aluminum covered steel wire, and a coating portion 114 made of aluminum (Al) is provided on the outer periphery of the steel wire 112. Corrosion of the steel wire 112 is suppressed by the covering portion 114. Note that the covering portion 114 may be made of zinc.

  Moreover, between the steel core part 100 and the external twisted-wire layer 200 mentioned later, it fills with anticorrosion grease, for example. Thereby, corrosion of steel core part 100 is controlled.

(External stranded wire layer)
An outer stranded wire layer 200 is provided outside the steel core 100 by twisting a plurality of strands 300 together. The external stranded wire layer 200 is configured as a conductor portion that mainly conducts current during power transmission, and each of the plurality of strands 300 included in the external stranded wire layer 200 is formed of, for example, aluminum (Al) or an aluminum alloy. . The strand 300 may be, for example, at least one of a heat resistant aluminum alloy wire (TAL), a super heat resistant aluminum alloy wire (ZTAL), and a special heat resistant aluminum alloy wire (XTAL).

  In the present embodiment, three or more external stranded wire layers 200 are provided. The power transmission line 10 according to the present embodiment includes, for example, a first external stranded wire layer 210, a second external stranded wire layer 220, and an outermost external stranded wire layer (a third external wire layer) from the steel core 100 side toward the outside. Twisted wire layer) 230. In the following, “element wire 300” is used as a general term for the elements constituting the first outer stranded wire layer 210, the second outer stranded wire layer 220, and the outermost outer stranded wire layer 230.

  The first external stranded wire layer 210 includes a plurality of strands 300 having a sector shape with a cross section, for example. Each strand 300 constituting the first external stranded wire layer 210 has a side surface along the radial direction. The plurality of strands 300 constituting the first external stranded wire layer 210 are in contact with each other at the side surface (surface contact), and are provided side by side in the circumferential direction. As a result, the plurality of strands 300 are densely filled in the first external stranded wire layer 210.

  The inner peripheral surface of the first external stranded wire layer 210 formed by providing the plurality of strands 300 side by side in the circumferential direction is along a concentric circle centered on the center of the steel core portion 100 when viewed from the axial direction. Provided. The inner peripheral surface of the first external stranded wire layer 210 is in contact with a part of the peripheral side surface of the core wire 110 of the steel core part 100.

  Similarly to the first external stranded wire layer 210, the second external stranded wire layer 220 is also composed of a plurality of strands 300 having a fan-shaped cross section, and the plurality of strands 300 constituting the second external stranded wire layer 220 are: They are in contact with each other on the side surfaces and are arranged side by side in the circumferential direction. Further, the inner peripheral surface of the second external stranded wire layer 220 is provided along a concentric circle centered on the center of the steel core portion 100 when viewed from the axial direction. The inner peripheral surface of the second external stranded wire layer 220 is in contact with the outer peripheral surface of the first external stranded wire layer 210 (surface contact).

  Thus, in the 1st external stranded wire layer 210 and the 2nd external stranded wire layer 220, the strand 300 whose section is a fan shape is filled densely. During rain, the space in which water droplets accumulate in the first external stranded wire layer 210 and the second external stranded wire layer 220 is reduced. Accumulation of water droplets in the first external stranded wire layer 210 and the second external stranded wire layer 220 is suppressed, and water droplets are prevented from oozing out to the surface of the power transmission line 10. Therefore, the generation of corona noise is suppressed. In addition, since the cross-sectional area of the strand 300 of the first external stranded wire layer 210 and the second external stranded wire layer 220 is larger than the cross-sectional area of the circular strand, the external stranded wire layer is composed of a circular strand. As compared with the case where the first external stranded wire layer 210 and the second external stranded wire layer 220 are increased, the current capacities can be increased.

(Outermost external stranded wire layer)
The outermost external stranded wire layer 230 is provided on the outermost side of the three or more external stranded wire layers 200. The outermost outer stranded wire layer 230 includes a smooth portion strand 310, a first protrusion strand 320, a second protrusion strand 330, and a groove portion strand 340 as follows.

(Smooth part strand)
A plurality of smooth portion strands 310 are provided side by side in the circumferential direction. The respective heights of the smooth portion strands in the radial direction are equal to each other, and the outer peripheral surface formed by the plurality of smooth portion strands 310 is a portion of the first protrusion strand 320 and the second protrusion strand 330 described later. It is formed more smoothly than

  Moreover, the cross section of the smooth part strand 310 is, for example, a kamaboko shape. The smooth part strand 310 has a side surface along the radial direction. The plurality of smooth portion strands 310 are in contact with each other on the side surfaces in the circumferential direction (surface contact).

  Moreover, the corner | angular part of the outer peripheral side of the smooth part strand 310 is smoothly formed in circular arc shape (it is formed in R shape). Each arcuate corner of each smooth part strand 310 faces each other in the circumferential direction, thereby forming a groove (not shown) between two adjacent smooth part strands 310. On the surface of the power transmission line 10, a plurality of grooves formed by arc-shaped corners of the smooth portion strand 310 are formed in a spiral shape along the axial direction.

  Here, when wind is blown to the power transmission line 10 from the short direction, the airflow flows to the leeward side along the surface of the power transmission line 10, and the arcuate corner of the smooth portion strand 310 on the surface of the power transmission line 10. In the plurality of grooves formed by the portions, airflow is mixed. The airflow once separated in each of the plurality of grooves approaches the leeward surface of the power transmission line 10 again. When the airflow in the vicinity of the power transmission line 10 repeats such a phenomenon by the respective groove portions, the separation point of the wind moves to the leeward side of the power transmission line 10. Thereby, the wind pressure load of the power transmission line 10 is reduced by reducing the pressure difference between the windward side and the leeward side of the power transmission line 10.

  The radius of curvature R of the corner portion on the outer peripheral side of the smooth portion strand 310 has an optimum range for reducing the wind pressure, and is, for example, 1.3 mm or more and 1.7 mm or less. When the radius of curvature of the corner portion on the outer peripheral side of the smooth portion strand 310 is within the above range, the amount of wind pressure reduction with respect to the ordinary electric wire (standard electric wire) of the power transmission line 10 can be 20% or more. The “ordinary wire (standard wire)” here means that all the strands in the outermost outer stranded wire layer have the same radial height, and all the strands in the outer stranded wire layer have a circular cross section. It is a certain transmission line.

(First protrusion strand and second protrusion strand)
Between the two smooth portion strands 310 among the plurality of smooth portion strands 310, a first protrusion strand 320 and a second projection strand 330 are provided. Each of the first protrusion strand 320 and the second protrusion strand 330 is provided higher in the radial direction than the smooth portion strand 310. Steps (not shown) are formed on the smooth portion strand 310 side of each of the first protrusion strand 320 and the second protrusion strand 330. On the surface of the power transmission line 10, a step on the smooth portion strand 310 side of each of the first protrusion strand 320 and the second protrusion strand 330 is spirally formed along the axial direction.

  Here, when wind is blown to the power transmission line 10 from the short direction, the wind is disturbed by the steps on both sides in the circumferential direction of each of the first protrusion strand 320 and the second protrusion strand 330, Karman vortices are less likely to be formed, and pressure fluctuations around the transmission line 10 are suppressed. Thereby, the wind noise from the power transmission line 10 is reduced.

  The height h in the radial direction from the outer peripheral surface of each of the smooth portion strands 310 of the first protrusion strand 320 and the second projection strand 330 is, for example, not less than 1.9 mm and not more than 2.4 mm. When the height h is 1.9 mm or more, the amount of wind noise reduction with respect to the ordinary electric wire of the power transmission line 10 can be 10 dB (A) or more. Thereby, it is possible to prevent complaints from neighboring residents from being caused by wind noise. Moreover, when the height h is 2.4 mm or less, the amount of wind pressure reduction with respect to the normal electric wire of the power transmission line 10 can be 20% or more.

  Moreover, the cross section of the 1st protrusion strand 320 and the 2nd protrusion strand 330 is a kamaboko shape, for example. The first protrusion strand 320 and the second protrusion strand 330 each have a side surface along the radial direction. The side surfaces of the first protruding portion wire 320 and the second protruding portion wire 330 on the smooth portion strand 310 side are in contact with (in contact with) the side surface of the smooth portion strand 310. In addition, the side surfaces of the first protruding element wire 320 and the second protruding element wire 330 on the groove element wire 340 side, which will be described later, are in contact with (in contact with) the side surfaces of the groove element wire 340.

  Moreover, the corner | angular part of each outer peripheral side of the 1st protrusion strand 320 and the 2nd protrusion strand 330 is smoothly formed in circular arc shape (it is formed in R shape). For example, the radius of curvature of the corner portion on the smooth portion strand 310 side of each of the first projection portion wire 320 and the second projection portion wire 330 is larger than the curvature radius of the corner portion on the groove portion strand 340 side described later. .

(Groove element wire)
A groove element wire 340 is provided between the first protrusion element wire 320 and the second protrusion element wire 330. The groove wire 340 is provided lower in the radial direction than the first protrusion wire 320 and the second protrusion wire 330. As a result, a groove (not shown) is formed between the first protruding element wire 320 and the second protruding element wire 330. On the surface of the power transmission line 10, a groove is formed in a spiral shape along the axial direction at a position between the first protruding element wire 320 and the second protruding element wire 330.

  Here, even when three or more external stranded wire layers 200 are provided by interposing the groove wire 340 between the first protrusion wire 320 and the second protrusion wire 330 ( The first protrusion strand 320 and the second protrusion strand 330 are not too close to each other (compared to the outer diameter of the power transmission line 10), and the first protrusion strand 320 and the second protrusion strand 330 The opening angle θ of the protrusion formed by the above is sufficiently secured. When wind is blown to the power transmission line 10 from the short direction, the wind is disturbed by the step between each of the first protruding element wire 320 and the second protruding element wire 330 and the smoothing element wire 310. Karman vortices are less likely to be formed, and pressure fluctuations around the transmission line 10 are suppressed. Thereby, the wind noise from the power transmission line 10 is reduced.

  In addition, the number of water droplets formed on the surface of the power transmission line 10 is reduced by capturing water droplets in the groove between the first protrusion strand 320 and the second protrusion strand 330 during the rain. . Further, the water droplets that have reached the vicinity of the first projecting element wire 320 and the second projecting element wire 330 do not droop significantly at the tips of the first projecting element wire 320 and the second projecting element wire 330, and the first protrusion It is captured between the part wire 320 and the second projecting part wire 330 and becomes flat. In addition, the water droplets captured between the first protrusion strands 320 and the second protrusion strands 330 are likely to fall early, and the protrusion of the water droplets is suppressed. In this way, corona discharge due to water droplets adhering to the surface of the power transmission line 10 is suppressed, and corona noise is reduced.

  The depth d in the radial direction from the outer peripheral surface of each of the first protruding element wire 320 and the second protruding element wire 330 to the outer peripheral surface of the groove element wire 340 has an optimum range for reducing corona noise. For example, it is 1.8 mm or more and 2.3 mm or less. When the depth d is within the above range, the corona hum sound level of the transmission line 10 can be improved by about 5 dB (A) as compared with the case where the depth d is outside the above range.

  Moreover, the cross section of the groove part strand 340 is, for example, a kamaboko shape. The groove part strand 340 has a side surface along the radial direction. As described above, the side surfaces of the groove wire 340 are in contact with (in contact with) the respective side surfaces of the first protrusion wire 320 and the second protrusion wire 330.

  Moreover, the corner | angular part of the outer peripheral side of the groove part strand 340 is smoothly formed in circular arc shape (it is formed in R shape).

(Other features of outermost external stranded wire layer)
Inner circumferential surface of outermost outer stranded wire layer 230 formed by providing smooth portion strand 310, first projection strand 320, second projection strand 330, and groove strand 340 side by side in the circumferential direction. Is provided along a concentric circle centered on the center of the steel core 100 when viewed from the axial direction. The inner peripheral surface of the outermost external stranded wire layer 230 is in contact with the outer peripheral surface of the second external stranded wire layer 220 (surface contact).

  Moreover, the surface of the smooth part strand 310, the 1st protrusion strand 320, the 2nd protrusion strand 330, and the groove part strand 340 in the outermost outer strand wire layer 230 may be subjected to hydrophilic treatment. . Examples of the hydrophilic treatment include a treatment of applying a hydrophilic material containing titanium oxide or the like. Thereby, a corona noise is suppressed by moving so that rain water may slide to the lowest point, without falling many on the surface of the power transmission line 10, and falling early.

  Only one set of the first protruding element wire 320, the second protruding element wire 330, and the groove element wire 340 is provided in the outermost outer stranded wire layer 230. As a result, by providing the first projecting element wire 320 and the second projecting element wire 330, the effect of increasing the wind pressure load due to the increase in the outer diameter of the power transmission line 10 is suppressed, and the wind force is maximized. Noise can be suppressed.

  The number of strands 300 in the outermost external stranded wire layer 230 (the total number of the smooth portion strand 310, the first projection strand 320, the second projection strand 330, and the groove strand 340) is 16 or more and 20 This is below. When the number of the strands 300 in the outermost external strand layer 230 is within the above range, an appropriate number of grooves are formed by the arc-shaped corners of the smooth portion strand 310, and the wind pressure load is efficiently reduced. be able to.

(Specific dimensions)
As specific dimensions of the power transmission line 10, for example, the diameter of the core wire 110 of the steel core part 100 is 3 mm or more and 5 mm or less, and the diameter of the steel core part 100 is 9 mm or more and 25 mm or less. Further, the radial height (from the inner peripheral surface to the outer peripheral surface) of each of the strands 300 of the first external stranded wire layer 210 and the second external stranded wire layer 220 is 3 mm or more and 5 mm or less. The width is 4 mm or more and 7 mm or less.

  The height in the radial direction of the smooth portion strand 310 in the outermost outer stranded wire layer 230 is 3 mm or more and 5 mm or less, and the width in the circumferential direction is 4 mm or more and 7 mm or less. Each of the first protrusion strand 320 and the second protrusion strand 330 has a radial height of 5 mm to 8 mm, and a circumferential width of 4 mm to 7 mm. The height in the radial direction of the groove wire 340 is 3 mm or more and 5 mm or less, and the width in the circumferential direction is 4 mm or more and 7 mm or less.

  In addition, the opening angle θ of the protrusion formed by the first protrusion element wire 320 and the second protrusion element wire 330 is, for example, not less than 45 ° and not more than 65 °. When the opening angle θ is in the above range, wind noise from the power transmission line 10 can be efficiently reduced.

  Moreover, the major axis (diameter on the side where the first projecting element wire 320 and the second projecting element wire 330 are provided) as a whole of the power transmission line 10 is 30 mm or more and 42 mm or less, and the shorter diameter (smooth part element wire 310 side). Is a diameter of 28 mm or more and 40 mm or less.

(2) Manufacturing method of power transmission line Next, the manufacturing method of the power transmission line 10 which concerns on this embodiment is demonstrated.

  One core wire 110 is arranged at the center as the first core wire, and the steel core portion 100 is formed by twisting the six core wires as the second core wire so as to cover the outer periphery of the first core wire. .

  Next, a plurality of strands 300 of the first external stranded wire layer 210 and the second external stranded wire layer 220 are formed by a wire drawing machine using an atypical die having a fan-shaped opening. Next, the 1st external stranded wire layer 210 is formed by twisting together the some strand 300 so that the outer periphery of the steel core part 100 may be covered. Next, the 2nd external strand wire layer 220 is formed by twisting together the some strand 300 so that the outer periphery of the 1st external strand wire layer 210 may be covered.

  Next, the smooth part strand 310 of the outermost outer stranded wire layer 230 is formed by a wire drawing machine using a modified die having a kamaboko-shaped opening. In addition, using a deformed die having an opening formed higher (longer) in the shorter direction than the smooth portion strand 310, the first protrusion strand 320 and the first projection strand 320 of the outermost outer stranded wire layer 230 are drawn by a wire drawing machine. Two protrusion strands 330 are formed. Further, using an atypical die having an opening formed lower (shorter) in the radial direction than the first projecting element wire 320 and the second projecting element wire 330, the outermost external stranded wire layer 230 is formed by a wire drawing machine. The groove part strand 340 is formed. Next, by twisting the smooth portion strand 310, the first projection portion strand 320, the second projection portion strand 330, and the groove portion strand 340 so as to cover the outer periphery of the second external stranded wire layer 220, The outer / external stranded wire layer 230 is formed.

  As described above, the power transmission line 10 according to the present embodiment is manufactured.

(3) Effects according to the present embodiment According to the present embodiment and its modifications, the following one or more effects are achieved.

(A) According to the present embodiment, the external strands are formed by interposing the groove strand 340 between the first projection strand 320 and the second projection strand 330 in the outermost external strand layer 230. Even when three or more layers 200 are provided, the first protrusion strand 320 and the second protrusion strand 330 are not too close (compared to the outer diameter of the power transmission line 10). The opening angle θ of the protrusion formed by the first protrusion strand 320 and the second protrusion strand 330 is sufficiently secured. When wind is blown to the power transmission line 10 from the short direction, the wind is disturbed by the step between each of the first protruding element wire 320 and the second protruding element wire 330 and the smoothing element wire 310. Karman vortices are less likely to be formed, and pressure fluctuations around the transmission line 10 are suppressed. Thereby, the wind noise from the power transmission line 10 can be reduced.

(B) According to the present embodiment, in the case where three or more external stranded wire layers 200 are provided, each of the first protruding wire 320 and the second protruding wire 330 in the outermost external stranded wire layer 230. The height h in the radial direction from the outer peripheral surface of the smooth portion strand 310 is not less than 1.9 mm and not more than 2.4 mm. When the height h is 1.9 mm or more, the amount of wind noise reduction with respect to the ordinary electric wire of the power transmission line 10 can be 10 dB (A) or more. Thereby, it is possible to prevent complaints from neighboring residents from being caused by wind noise. Moreover, when the height h is 2.4 mm or less, the amount of wind pressure reduction with respect to the normal electric wire of the power transmission line 10 can be 20% or more.

(C) According to this embodiment, the corner | angular part of the outer peripheral side of the smooth part strand 310 in the outermost external strand wire layer 230 is smoothly formed in circular arc shape (it is formed in R shape). In the case where three or more external stranded wire layers 200 are provided, the radius of curvature R of the corner portion on the outer peripheral side of the smooth portion strand 310 is 1.3 mm or greater and 1.7 mm or less. When the radius of curvature of the corner portion on the outer peripheral side of the smooth portion strand 310 is within the above range, the amount of wind pressure reduction with respect to the ordinary electric wire (standard electric wire) of the power transmission line 10 can be 20% or more.

(D) According to the present embodiment, when three or more external stranded wire layers 200 are provided, each of the first protrusion strand 320 and the second protrusion strand 330 in the outermost external stranded wire layer 230 is provided. The radial depth d from the outer peripheral surface to the outer peripheral surface of the groove element wire 340 has an optimum range for reducing corona noise, and is, for example, 1.8 mm or more and 2.3 mm or less. When the depth d is within the above range, the corona hum sound level of the transmission line 10 can be improved by about 5 dB (A) as compared with the case where the depth d is outside the above range.

(E) According to the present embodiment, only one set of the first protruding element wire 320, the second protruding element wire 330, and the groove element wire 340 is provided in the outermost external stranded wire layer 230. By increasing the number of pairs including the first protrusion strand 320 and the second protrusion strand 330, wind noise is effectively suppressed, while the outer diameter of the power transmission line 10 increases, and the smooth portion strand is increased. There exists a tendency for the effect of low wind pressure by the corner | angular part of the outer peripheral side of a line | wire to be provided in circular arc shape to reduce (wind pressure load increases). Therefore, by providing only one set of the first protruding element wire 320, the second protruding element wire 330, and the groove element wire 340 in the outermost outer stranded wire layer 230, the effect of reducing the effect of reducing the wind pressure is suppressed. However, it is possible to suppress wind noise to the maximum.

(F) According to the present embodiment, each of the plurality of strands 300 constituting the external stranded wire layer 200 has a side surface along the radial direction. The plurality of strands 300 constituting the external stranded wire layer 200 are in contact with each other on the side surfaces in the circumferential direction (surface contact). Thereby, in each external twisted wire layer 200, a plurality of strands 300 are densely filled. When raining, the space where water droplets accumulate in the external stranded wire layer 200 is reduced. Water droplets are prevented from accumulating inside the external stranded wire layer 200, and water droplets are prevented from oozing out to the surface of the power transmission line 10. Therefore, the generation of corona noise is suppressed. In addition, since the cross-sectional area of the strand 300 of the external stranded wire layer 200 is larger than the cross-sectional area of the circular strand, the external stranded wire layer is compared with the case where the external stranded wire layer is composed of circular strands. The current capacity of 200 can be increased.

  As described above, according to the present embodiment, when three or more external stranded wire layers 200 are provided, it is possible to provide the power transmission line 10 with reduced wind noise, wind pressure load, and corona noise.

<Other Embodiments of the Present Invention>
As mentioned above, although embodiment and modification of this invention were described concretely, this invention is not limited to the above-mentioned embodiment and modification, and can be variously changed in the range which does not deviate from the summary.

  In the above-mentioned embodiment, although the case where the cross section of each strand 300 of the 1st external stranded wire layer 210 and the 2nd external stranded wire layer 220 was a fan shape was demonstrated, the 1st external stranded wire layer and the 2nd external stranded wire layer The cross section of each strand of the line layer may be circular.

  Moreover, although the above-mentioned embodiment demonstrated the case where three layers of external twisted wire layers were provided, for example, four or more layers of external twisted wire layers may be provided.

(1) Production of transmission line sample In order to find the optimum conditions for reducing wind noise, wind pressure load and corona noise, the following transmission line sample and a normal transmission line sample for comparison were produced.

<Transmission line sample>
Nominal cross section:
610mm ² equivalent external twisted layer:
Height h in the radial direction from the outer peripheral surface of each of the smooth portion strands of the three-layer first projection strand and the second projection strand:
1 mm or more and 2.5 mm or less (For the sake of comparison, a power transmission line sample (h = 0 mm) in which the first protrusion element wire and the second protrusion element wire are not provided was also manufactured.)
Curvature radius R of the outer peripheral side of the smooth portion strand:
0.5 mm or more and 2.5 mm or less Depth d in the radial direction from the outer peripheral surface of each of the first protruding element wire and the second protruding element wire to the outer peripheral surface of the groove element wire:
1.5 mm or more and 2.5 mm or less Number of strands of outermost outer stranded wire layer:
Number of pairs of first protrusion strands, second protrusion strands and groove strands provided in the 18 outermost external stranded wires:
1 set or 2 sets (only FIG. 6 to be described later, arranged symmetrically across the center)

<Normal wire sample>
Nominal cross section:
610mm ² equivalent external twisted layer:
3 layers All strands in the outermost outer stranded wire layer have the same radial height All cross-sections of all strands in the outer stranded wire layer are circular

(2) Performance test of power transmission line sample The above power transmission line sample and normal wire sample were subjected to a performance test as follows.

(Wind noise test)
Using a wind tunnel facility, wind with a wind speed of 20 m / s was blown from the short direction to the above-described transmission line sample and ordinary wire sample, and wind noise from each of the transmission line sample and ordinary wire sample was measured.

(Wind pressure load test)
Using the wind tunnel equipment, wind of 40 m / s was blown from the short side direction to the above-mentioned transmission line sample and the ordinary electric wire sample, and the respective wind pressure loads of the transmission line sample and the ordinary electric wire sample were measured.

(Corona noise test)
A voltage with a maximum surface potential gradient Gmax of 15 kV / cm is applied to the above transmission line sample and ordinary wire sample, and the corona ham sound level from each of the transmission line sample and ordinary wire sample is measured during equivalent light rain. did.

  In addition, the corona noise test of the transmission line was conducted in a corona cage equipped with a power transmission facility and a water injection facility. The water injection facility artificially drops a certain amount of rain (for example, 30 mm / h in the domestic test method). The noise in this water injection state is referred to as “heavy rain” noise, and the average value of the noise 1 minute, 1.5 minutes and 2 minutes after the water injection stop is referred to as “equivalent light rain” noise.

(4) Performance Test Result of Transmission Line Sample Next, the performance test result of the transmission line sample will be described with reference to FIGS.

FIG. 2 is a diagram illustrating the amount of wind noise reduction with respect to the radial height h from the outer peripheral surface of the smooth portion strand of each of the first protrusion strand and the second projection strand. In FIG. 2, the amount of wind noise reduction is L ₀ when the wind noise level of the normal wire sample at the wind speed of 20 m / s is L ₀ and the wind noise level of the transmission line sample at the wind speed of 20 m / s is L. obtained by the -L ₀ (unit dB (A)).

  As shown in FIG. 2, the amount of wind noise reduction increases as the radial height h from the outer peripheral surface of the smooth portion strand of each of the first and second projection strands increases. Monotonically increased. That is, it can be seen that wind noise can be reduced as the height h increases. It can be seen that when the height h is 1.9 mm or more, the amount of wind noise reduction with respect to the normal wire sample of the transmission line sample can be 10 dB (A) or more.

  In addition, when it becomes 10 dB (A) or more higher than surrounding noise, there is a possibility that complaints from neighboring residents may occur. For this reason, the target value of the wind noise reduction amount of the transmission line is set to 10 dB (A), for example. As described above, when the height h in the radial direction from the outer peripheral surface of the smooth portion strand of each of the first protrusion strand and the second projection strand is 1.9 mm or more, The amount of wind noise reduction with respect to the normal electric wire sample can be 10 dB (A) or more, thereby suppressing the occurrence of complaints from neighboring residents due to the wind noise.

FIG. 3 is a diagram showing the amount of wind pressure reduction with respect to the height h in the radial direction from the outer peripheral surface of the smooth portion strand of each of the first protrusion strand and the second projection strand. In FIG. 3, the amount of wind pressure reduction is defined as F ₀ when the wind pressure load of the normal wire sample at the wind speed of 40 m / s is F ₀ and the wind pressure load of the transmission line sample at the wind speed of 40 m / s is F. ₀ ) / F ₀ × 100 (unit%).

  As shown in FIG. 3, as the height h in the radial direction from the outer peripheral surface of each smooth portion strand of the first protrusion strand and the second protrusion strand increases, the wind pressure reduction amount becomes Monotonously decreased. That is, in order to reduce the wind pressure load, it can be said that the height h is preferably not larger than necessary. It can be seen that when the height h is 2.4 mm or less, the amount of reduction in wind pressure with respect to the normal wire sample of the transmission line sample can be 20% or more.

  From the results of FIGS. 2 and 3, the radial height h from the outer peripheral surface of each smooth portion strand of the first protrusion strand and the second projection strand is 1.9 mm or more and 2.4 mm or less. It is preferable that

  FIG. 4 is a diagram showing a wind pressure reduction amount with respect to a curvature radius R of a corner portion on the outer side in the radial direction of the smooth portion strand. As shown in FIG. 4, the wind pressure reduction amount tended to be convex upward with respect to the radius of curvature R of the outer corner in the radial direction of the smooth portion strand. That is, it can be seen that the radius of curvature R has an optimum range for reducing the wind pressure load. It can be seen that when the radius of curvature R is 1.3 mm or greater and 1.7 mm or less, the amount of wind pressure reduction of the power transmission line sample relative to the normal wire sample can be 20% or greater. Therefore, it is preferable that the curvature radius R of the corner | angular part of the radial direction outer side of a smooth part strand is 1.3 mm or more and 1.7 mm or less.

  FIG. 5 is a diagram illustrating the corona hum sound level with respect to the radial depth d from the outer peripheral surface of each of the first and second protrusion strands to the outer peripheral surface of the groove strand. As shown in FIG. 5, the corona hum sound level with respect to the radial depth d from the outer peripheral surface of each of the first projecting element wire and the second projecting element wire to the outer peripheral surface of the groove element wire. Showed a downward trend. That is, the depth d has an optimum range for reducing the corona ham sound level. When the depth d is 1.8 mm or more and 2.3 mm or less, the corona hum sound level of the transmission line 10 can be improved by about 5 dB (A) as compared with the case where the depth d is out of the above range. I understand. Therefore, it is preferable that the radial depth d from the outer peripheral surface of each of the first protrusion strand and the second protrusion strand to the outer peripheral surface of the groove strand is 1.8 mm or more and 2.3 mm or less. .

  FIG. 6 is a diagram showing a wind pressure reduction amount with respect to the number of sets of the first protruding element wire, the second protruding element wire, and the groove element wire. When the number of sets of the first protruding element wire, the second protruding element wire, and the groove element wire is zero, the wind pressure reduction amount is 25% at the maximum. As in the above-described embodiment, when the number of sets of the first protruding element wire, the second protruding element wire, and the groove element wire is one set, the smooth portion element is caused by an increase in the outer diameter of the transmission line. The effect of lowering the wind pressure due to the corners on the outer peripheral side of the line being provided in an arc shape is reduced, and the amount of wind pressure reduction is about 20%. When the number of pairs of the first protruding element wire, the second protruding element wire, and the groove element wire is two, the effect of reducing the wind pressure by providing the outer peripheral corner of the smooth portion element wire in an arc shape Is further reduced, and the amount of wind pressure reduction is about 12%. Thus, while the number of sets including the first protrusion strand and the second protrusion strand increases, wind noise is effectively suppressed, while the outer diameter of the transmission line increases, and the smooth portion It can be seen that the effect of lowering the wind pressure by the corners on the outer peripheral side of the strands being formed in an arc shape tends to decrease (wind pressure load increases). Therefore, it is preferable to provide only one set of the first protruding element wire, the second protruding element wire, and the groove element wire in the outermost outer stranded wire layer. Thereby, it is possible to suppress the wind noise to the maximum while suppressing the influence of the effect of lowering the wind pressure.

(5) Manufacture of power transmission line Based on the test result of the power transmission line sample, the power transmission lines of Examples 1 and 2 were manufactured under the optimum conditions as follows.

FIG. 7 is a cross-sectional view orthogonal to the axial direction of the power transmission line of the first embodiment. The configuration of the power transmission line of Example 1 shown in FIG. 7 is as follows.
<Power Transmission Line of Example 1>
Nominal cross section:
610 mm ² equivalent (corresponding to the outer diameter 34.2mm on plain wire)
External stranded wire layer:
Height h in the radial direction from the outer peripheral surface of each of the smooth portion strands of the three-layer first projection strand and the second projection strand:
2.15mm
Curvature radius R of the outer peripheral side of the smooth portion strand:
1.5mm
Radial depth d from the outer peripheral surface of each of the first protrusion strand and the second protrusion strand to the outer peripheral surface of the groove portion strand:
2.0mm
Number of strands of outermost outer stranded wire layer:
Number of pairs of first protrusion strands, second protrusion strands and groove strands provided in the 18 outermost external stranded wires:
1 pair

FIG. 8 is a cross-sectional view orthogonal to the axial direction of the power transmission line of the second embodiment. The configuration of the transmission line of Example 2 shown in FIG. 8 is as follows.
<Power Transmission Line of Example 2>
Nominal cross section:
680 mm ² equivalent (corresponding to the outer diameter 35.1mm on plain wire)
External stranded wire layer:
Height h in the radial direction from the outer peripheral surface of each of the smooth portion strands of the three-layer first projection strand and the second projection strand:
2.2mm
Curvature radius R of the outer peripheral side of the smooth portion strand:
1.5mm
Radial depth d from the outer peripheral surface of each of the first protrusion strand and the second protrusion strand to the outer peripheral surface of the groove portion strand:
2.1mm
Number of strands of outermost outer stranded wire layer:
Number of pairs of first protrusion strands, second protrusion strands and groove strands provided in the 18 outermost external stranded wires:
1 pair

  When the transmission lines of Examples 1 and 2 were installed between two steel towers with a span length of 300 m, the wind noise caused by the wind blown from the short direction was reduced as compared with the normal electric wires, and the wind pressure load was normal electric wires. Was reduced. In addition, corona noise during rainfall was reduced compared to ordinary wires.

  As described above, according to the present invention, when three or more external stranded wire layers are provided, it is possible to provide a power transmission line with reduced wind noise, wind pressure load, and corona noise.

DESCRIPTION OF SYMBOLS 10 Transmission line 100 Steel core part 110 Core wire 112 Steel wire 114 Covering part 200 External twisted wire layer 210 1st external twisted wire layer 220 2nd external twisted wire layer 230 Outermost external twisted wire layer (3rd external twisted wire layer)
300 strand 310 smooth portion strand 320 first projection strand 330 second projection strand 340 groove strand

Claims (7)

A steel core,
Three or more external stranded wire layers provided by twisting a plurality of strands on the outside of the steel core, and
Have
Outermost external stranded wire layer located on the outermost side among the three or more external stranded wire layers,
A plurality of smooth portion strands provided side by side along the circumferential direction;
A first protruding element wire and a second protruding element wire that are provided between two of the plurality of smooth portion strands and are provided higher in the radial direction than the smooth portion strand;
A groove element wire provided between the first protrusion element wire and the second protrusion element wire, and provided in a radial direction lower than the first protrusion element wire and the second protrusion element wire;
Have
The height in the radial direction from the outer peripheral surface of the smooth portion strand of each of the first protrusion strand and the second projection strand is 1.9 mm or more and 2.4 mm or less,
A corner portion on the outer peripheral side of each of the plurality of smooth portion strands is formed in an arc shape,
The radius of curvature of the corner portion on the outer peripheral side of the smooth portion strand is 1.3 mm or more and 1.7 mm or less,
The radial depth from the outer peripheral surface of each of the first protruding element wire and the second protruding element wire to the outer peripheral surface of the groove element wire is 1.8 mm or more and 2.3 mm or less,
The first projecting element wire, the second projecting element wire, and the groove element wire are provided in only one set in the outermost outer stranded wire layer,
The number of the said some strands which comprise the said outermost external strand wire layer is 16 or more and 20 or less, The power transmission line characterized by the above-mentioned. A steel core,
Three or more external stranded wire layers provided by twisting a plurality of strands on the outside of the steel core, and
Have
Outermost external stranded wire layer located on the outermost side among the three or more external stranded wire layers,
A plurality of smooth portion strands provided side by side along the circumferential direction;
A first protruding element wire and a second protruding element wire that are provided between two of the plurality of smooth portion strands and are provided higher in the radial direction than the smooth portion strand;
A groove element wire provided between the first protrusion element wire and the second protrusion element wire, and provided in a radial direction lower than the first protrusion element wire and the second protrusion element wire;
Have
The height in the radial direction from the outer peripheral surface of the smooth portion strand of each of the first protrusion strand and the second projection strand is 1.9 mm or more and 2.4 mm or less. power line. A corner portion on the outer peripheral side of each of the plurality of smooth portion strands is formed in an arc shape,
The power transmission line according to claim 2, wherein a radius of curvature of a corner portion on the outer peripheral side of the smooth portion strand is 1.3 mm or more and 1.7 mm or less. The radial depth from the outer peripheral surface of each of the first protruding element wire and the second protruding element wire to the outer peripheral surface of the groove element wire is 1.8 mm or more and 2.3 mm or less. The power transmission line according to claim 2 or 3. The said 1st protrusion strand, the said 2nd protrusion strand, and the said groove part strand are provided only in 1 set in the said outermost outer strand wire layer, The any one of Claims 2-4 characterized by the above-mentioned. The transmission line described in 1. 6. The power transmission line according to claim 2, wherein the number of the plurality of strands constituting the outermost external stranded wire layer is 16 or more and 20 or less. Each of the plurality of strands constituting the external stranded wire layer has a side surface along a radial direction,
The power transmission line according to any one of claims 2 to 6, wherein the plurality of strands constituting the external stranded wire layer are in contact with each other on the side surface in a circumferential direction.