JP2019160709A - Carbon nanotube strand, power transmission line, method for manufacturing carbon nanotube strand, and method for constructing power transmission line - Google Patents

Abstract

To provide a carbon nanotube strand utilizing the excellent characteristics of a carbon nanotube, a power transmission line using the carbon nanotube strand, and a method for manufacturing such a carbon nanotube strand.SOLUTION: A carbon nanotube strand 1 comprises a carbon nanotube fiber 2 formed only from the carbon nanotube and a pipe 3. A plurality of the carbon nanotube fibers 2 are housed in the pipe 3 and are firmly held from the outside by the pipe 3 over the entire region in a longitudinal direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a carbon nanotube element wire, a power transmission line, a carbon nanotube element manufacturing method, and a power transmission line construction method.

In the past, power transmission lines such as overhead power transmission lines were often formed of copper wire, but now, ACSR (steel core aluminum stranded wire) including hard aluminum wire having a specific gravity lighter than copper wire is used. Has become common (see, for example, Patent Document 1).
On the other hand, carbon nanotubes are characterized by having a lower specific gravity than steel wires and aluminum wires, as well as stronger tensile strength than steel wires and higher electrical conductivity than aluminum wires. Is under development (see, for example, Patent Document 2).

Japanese Examined Patent Publication No. 57-56164 Japanese Patent Laid-Open No. 2017-17489

  By the way, the CNT electric wire described in Patent Document 2 is formed by covering a plurality of carbon nanotube wires formed by twisting a plurality of carbon nanotube bundles with an insulating coating. Such a CNT electric wire can be used without any problem when used as a power line, a signal line, a distribution line or the like of an automobile or industrial equipment.

However, in order to form a transmission line using such a CNT electric wire, an attempt is made to twist a plurality of CNT electric wires, or to twist a CNT electric wire and a strand such as a copper wire, an aluminum wire, or a steel wire. Then, the shape of a CNT electric wire will collapse and a power transmission line cannot be formed well.
For this reason, there is a problem that the excellent characteristics of the carbon nanotube cannot be utilized in a power transmission line such as an overhead power transmission line.

  The present invention has been made in view of the above-mentioned problems. A carbon nanotube element wire that makes use of the excellent characteristics of carbon nanotubes, a power transmission line using the same, a method for producing such a carbon nanotube element wire, and the like The purpose is to provide.

In order to solve the above problem, the invention according to claim 1 is a carbon nanotube strand,
A carbon nanotube fiber formed only of carbon nanotubes, and a pipe,
A plurality of the carbon nanotube fibers are housed in the pipe in a state of being firmly held from the outside by the pipe over the entire lengthwise direction.

  The invention described in claim 2 is the carbon nanotube strand according to claim 1, wherein the pipe is made of metal.

  According to a third aspect of the present invention, in the carbon nanotube element wire according to the second aspect, the metal pipe is formed of aluminum, stainless steel, copper, or an alloy thereof.

  The invention according to claim 4 is the carbon nanotube strand according to claim 1, wherein the pipe is made of a heat-shrinkable resin.

  The invention according to claim 5 is characterized in that a plurality of carbon nanotube strands according to any one of claims 1 to 4 are twisted in a power transmission line.

  The invention according to claim 6 is characterized in that in the power transmission line, a plurality of strands including the carbon nanotube strand according to any one of claims 1 to 4 are twisted. And

  The invention according to claim 7 is the power transmission line according to claim 6, wherein the element wire includes an element wire formed of aluminum, copper, or an alloy thereof.

  The invention according to claim 8 is the power transmission line according to claim 6 or claim 7, wherein the element wire includes an aluminum-coated steel wire or a galvanized steel wire.

The invention according to claim 9 is a method for producing a carbon nanotube strand,
Inserting a plurality of carbon nanotube fibers into a metal pipe;
Thinning the pipe, forming a state in which the plurality of carbon nanotube fibers are firmly gripped from the outside with the pipe over the entire lengthwise direction;
It is characterized by including.

Invention of Claim 10 in the manufacturing method of a carbon nanotube strand,
Inserting a plurality of carbon nanotube fibers into a heat-shrinkable resin pipe;
Shrinking the pipe by heating to form a state in which the plurality of carbon nanotube fibers are firmly gripped from the outside by the pipe over the entire longitudinal direction; and
It is characterized by including.

  The invention according to claim 11 is the method for producing a carbon nanotube strand according to claim 9 or 10, wherein the carbon nanotube fiber is 1 for each predetermined number before being inserted into the pipe. It is characterized by being bundled with one or a plurality of carbon nanotube fibers.

  The invention according to claim 12 is characterized in that, in the construction method of the power transmission line, the power transmission line according to any one of claims 5 to 8 is used.

  According to the present invention, a carbon nanotube strand that takes advantage of the excellent properties of carbon nanotubes such as high tensile strength, light weight, and high conductivity, a power transmission line using the carbon nanotube strand, and production of such a carbon nanotube strand A method or the like can be provided.

It is sectional drawing showing the structure of the carbon nanotube strand which concerns on this embodiment. It is the figure which showed the process of forming a fiber bundle from a plurality of carbon nanotube fibers. (A) It is a figure showing the carbon nanotube fiber twisted, (B) It is a figure showing the carbon nanotube fiber bundled with the carbon nanotube fiber. It is the figure which showed the process of manufacturing a carbon nanotube strand. (A) It is sectional drawing showing the state by which the carbon nanotube fiber was inserted in the state with a clearance gap in a pipe, (B) It is sectional drawing showing the state by which the carbon nanotube fiber was firmly hold | gripped from the outer side by the pipe. (A), (B) It is a figure showing the example of the power transmission line using the carbon nanotube strand which concerns on this embodiment. (A), (B) It is a figure showing the example of the power transmission line using the carbon nanotube strand which concerns on this embodiment. It is a figure showing the example of the power transmission line using the carbon nanotube strands concerning this embodiment.

Hereinafter, the carbon nanotube strands and the like according to the present embodiment will be described with reference to the drawings. However, the embodiments described below are given various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.
In the following drawings, in order to make the carbon nanotube fibers 2 easy to see, the carbon nanotube fibers 2 are described as being much thicker than the actual carbon nanotube fibers 1 and pipes 3.

[Carbon nanotube strands]
First, the carbon nanotube element wire according to the present embodiment will be described. FIG. 1 is a cross-sectional view illustrating a configuration of a carbon nanotube element wire 1 according to the present embodiment.
The carbon nanotube strand 1 includes a carbon nanotube fiber 2 and a pipe 3, and a plurality of carbon nanotube fibers 2 are firmly held from the outside by the pipe 3 over the entire area in the longitudinal direction. It is stored.

This will be specifically described below. Hereinafter, the carbon nanotube element wire 1 may be simply referred to as an element wire 1.
The carbon nanotube fiber 2 is formed of only carbon nanotubes.
The carbon nanotube is a fibrous substance having a structure in which a graphene sheet having a hexagonal lattice structure of carbon atoms is rolled into a single-layer or a substantially coaxial multilayer cylinder.

In the present embodiment, the pipe 3 is made of metal, for example, aluminum. It can be formed of stainless steel, copper, or an alloy thereof (aluminum alloy, stainless alloy, copper alloy).
If the pipe 3 is made of metal, as will be described later (see FIG. 2 described later), the pipe 3 through which the plurality of carbon nanotube fibers 2 are inserted is thinned to produce the strand 1. Since the pipe 3 contracted in the radial direction is in a state of firmly gripping the plurality of carbon nanotube fibers 2 from the outside over the entire region in the longitudinal direction, the strand 1 according to the present embodiment can be easily and accurately formed. It becomes possible.

The pipe 3 may be made of a heat shrinkable resin.
If the pipe 3 is made of a heat-shrinkable resin, as will be described later, the pipe 3 through which a plurality of carbon nanotube fibers 2 are inserted is heated and thinned to produce the element wire 1, and thus the pipe 3 is shrunk by heating. The pipe 3 is in a state in which the plurality of carbon nanotube fibers 2 housed therein are firmly gripped from the outside over the entire area in the longitudinal direction, and the strand 1 according to the present embodiment is easily and accurately formed. Is possible.

The above-mentioned “state in which the plurality of carbon nanotube fibers 2 are firmly held from the outside by the pipe 3 over the entire length direction” means that the pipe 3 and the carbon nanotube fibers 2 and the carbon nanotube fibers are contracted by the contraction force of the pipe 3. The two are strongly pressed in the radial direction of the strand 1, and for example, when the pipe 3 is not moved, a part of the carbon nanotube fiber is held so as not to move with a strong frictional force even if it is moved in the longitudinal direction. The state that has been done.
Therefore, the carbon nanotube element wire 1 according to the present embodiment is hard like a copper wire, an aluminum wire, a steel wire or the like. Therefore, for example, it is difficult to caulk the carbon nanotube element wire 1 and attach a terminal or the like in the same manner as the CNT electric wire described in Patent Document 2 described above. The terminal is attached to the wire 1 in the same manner as the terminal is attached to a copper wire, an aluminum wire, a steel wire or the like.

Carbon nanotubes have a tensile strength of 11 to 53 GPa, which is higher than that of steel wires, and a specific gravity of 1.3 to 2.0 g / cm ³ , which is lighter than aluminum (Naoto Nakajima, 1 outside, “New Series New Nano Carbon nanotubes as materials-Recent developments (from biotechnology to energy) (1) ", DOJIN NEWS No.146 / 2013 [searched on March 5, 2018], Internet <http://www.dojindo.co. jp / letterj / 146 / review / 02.html>). And it has the electrical conductivity equivalent to a copper wire.

Therefore, the carbon nanotube fiber 1 according to this embodiment in which the carbon nanotube fiber 2 formed only of carbon nanotubes is used as a conductor has a tensile strength stronger than a steel wire, lighter than an aluminum wire, It is a strand that takes advantage of the excellent characteristics of carbon nanotubes having high electrical conductivity equivalent to that of the wire.
As described above, according to the carbon nanotube element wire 1 according to the present embodiment, it is possible to provide an element element that takes advantage of the excellent characteristics of carbon nanotubes such as high tensile strength, light weight, and high electrical conductivity. Become.

Further, the carbon nanotube element wire 1 according to the present embodiment is different from the CNT electric wire described in Patent Document 2 described above, which is suitable for power lines, signal lines, and distribution lines for automobiles, industrial equipment, etc. Hard like aluminum wire, steel wire, etc., suitable for use in power transmission lines.
Therefore, as described later, it is possible to form a power transmission line that takes advantage of the characteristics of the carbon nanotubes by twisting the strands 1 or twisting them together with an aluminum wire, a conductive wire, a steel wire, or the like. This point will be described later.

Further, the carbon nanotube element wire 1 according to the present embodiment is different from the CNT electric wire described in Patent Document 2 described above, which is suitable for power lines, signal lines, and distribution lines for automobiles, industrial equipment, etc. Hard like aluminum wire, steel wire, etc., suitable for use in power transmission lines.
Therefore, as described later, it is possible to form a power transmission line that takes advantage of the characteristics of the carbon nanotubes by twisting the strands 1 or twisting them together with an aluminum wire, a conductive wire, a steel wire, or the like. This point will be described later.

[Method for producing carbon nanotube wire]
Next, the manufacturing method of the carbon nanotube strand 1 which concerns on this embodiment is demonstrated. The carbon nanotube wire 1 can be manufactured by performing a wire drawing process, an extrusion process, a rolling process, or the like on a pipe 3 in which a plurality of carbon nanotube fibers 2 are inserted.
This will be specifically described below. 2-4 is a figure which shows an example of the manufacturing method of the strand 1. FIG.

For example, as shown in FIG. 2, a plurality of carbon nanotube fibers 2 are each pulled out from the bobbin 11 and collected by a roller 12.
Then, the bundled carbon nanotube fibers 2 are applied to a fiber bundle forming machine 13 to form a fiber bundle 20. The formed fiber bundle 20 is wound around the supply bobbin 14.

For example, as shown in FIG. 3A, the fiber bundle 20 can be formed by twisting the plurality of carbon nanotube fibers 2 to form the fiber bundle 20.
Further, when the carbon nanotube fiber 2 is twisted, the carbon nanotube fiber 2 is stretched more than the tensile force compared with the case where the carbon nanotube fiber 2 is not twisted, and the tensile strength is reduced because no force is applied to the carbon nanotube fiber 2 linearly. As described above, there is a possibility that the effect of the characteristics of the carbon nanotube having higher tensile strength than the steel wire is reduced.
Therefore, in such a case, for example, as shown in FIG. 3B, a predetermined number of carbon nanotube fibers 2 are collected and bundled with one carbon nanotube fiber 2a to form a fiber bundle 20. It is possible to configure. Instead of bundling with a single carbon nanotube fiber 2a, it is also possible to configure such that it is bundled with a plurality of carbon nanotube fibers 2a.

If comprised in this way, the several carbon nanotube fiber 2 other than the carbon nanotube fiber 2a will be arrange | positioned in the strand 1 in the straight state which is not twisted.
Therefore, almost all of the carbon nanotube fibers 2 except the carbon nanotube fibers 2a that bundle a plurality of carbon nanotube fibers 2 can be used as they are without reducing the tensile strength of the carbon nanotubes. It becomes possible to form the strand 1 in which the effect of (tensile strength in this case) is sufficiently exhibited.

On the other hand, as shown in FIG. 4, for example, the aluminum plate 30 is formed into a tubular shape by forming rolls 15 a and 15 b, and the ends of the aluminum plate 30 formed into a tubular shape are continuously welded by beat welding or the like with a welding machine 16. The pipe 3 is formed.
In addition, the board formed with the stainless plate, the copper plate, or its alloy instead of the aluminum plate may be sufficient.

Then, the fiber bundle 20 formed by twisting the plurality of carbon nanotube fibers 2 or bundling the plurality of carbon nanotube fibers 2 as described above is pulled out from the supply bobbin 14 and inserted into the formed pipe 3. Then, the pipe 3 is thinned, for example, by drawing the pipe 3 through a die 17.
In addition, after thinning the fiber bundle 20, that is, the pipe 3 through which the plurality of carbon nanotube fibers 2 are inserted as described above, the thinning process may be further performed once or a plurality of times.

  In the above case, at the stage where a plurality of carbon nanotube fibers 2 are inserted into the formed pipe 3 (the stage before passing through the die 17), for example, as shown in FIG. Is inserted into the pipe 3 with a gap.

However, as described above, when the pipe 3 is thinned by passing it through a die 17 and drawing the pipe 3, the pipe 3 shrinks in the radial direction, and the carbon nanotube fiber 2 is directed inward from the outside. Press.
Therefore, the carbon nanotube fiber 2 moves in the pipe 3 and gradually there is no gap between them.
Then, as shown in FIG. 5B, there is no gap between the carbon nanotube fibers 2 in the pipe 3, and the carbon nanotube fibers 2 are pressed inward by further thinning the pipe 3. Is done.

In the present embodiment, by thinning the pipe 3 in this manner, a state is formed in which the plurality of carbon nanotube fibers 2 are firmly held from the outside by the pipe 3 over the entire region in the longitudinal direction as described above. It has become.
In the above case, when the pipe 3 is thinned, the pipe 3 extends in the longitudinal direction, but the carbon nanotube fiber 2 hardly extends. Therefore, the carbon nanotube fiber 2 is fed into the die 17 at a speed faster than the pipe 3 is fed into the die 17.

Although not shown, it is also possible to configure the fiber bundle 20 in which the carbon nanotube fibers 2 are bundled to be bundled together by a predetermined number. Further, it is possible to configure such that the bundles bundled in such a manner are further bundled together by a predetermined number, and how many times the carbon nanotube fibers 2 and the fiber bundles 20 are bundled can be appropriately determined.
At that time, as shown in FIG. 3B, a predetermined number of fiber bundles 20 and the like may be bundled with one or a plurality of carbon nanotube fibers 2a. That is, the carbon nanotube fiber 2 in FIG. 3B can be regarded as the fiber bundle 20, and the plurality of fiber bundles 20 can be bundled with the carbon nanotube fibers 2a. Thereby, since the tensile strength of the carbon nanotube is exhibited as it is without being reduced by twisting, the tensile strength of the strand 1 can be made extremely strong.

  Although not shown in the figure, when the strand 1 is formed by further bundling a plurality of fiber bundles 20, a plurality of supply bobbins 14 are provided in FIG. 4, and the fiber bundles 20 are drawn from each supply bobbin 14. The pipe 3 may be thinned by inserting the pipe 3 into the pipe 3 and drawing the pipe 3 through a die 17.

On the other hand, as described above, even when the pipe 3 is formed of a heat-shrinkable resin, the carbon nanotube element wire 1 can be manufactured basically in the same manner as the method shown in FIG.
That is, a plurality of carbon nanotube fibers 2 drawn out from the bobbin 11 are bundled with rollers 12 and 12 as shown in FIGS. 3A and 3B, for example.
Further, instead of the aluminum plate 30, a heat-shrinkable resin sheet is formed into a tubular shape by forming rolls 15 a and 15 b, and the pipes 3 are formed by welding or bonding the end portions.

Then, a plurality of carbon nanotube fibers 2 bundled as described above are inserted into the formed pipe 3.
Then, the pipe 3 through which the plurality of carbon nanotube fibers 2 are inserted is heated by a heating device instead of passing through the die 17, so that the pipe 3 is thermally contracted to be thinned, so that the longitudinal direction is as described above. It is possible to form a state in which the plurality of carbon nanotube fibers 2 are firmly held from the outside by the pipe 3 over the entire area.

That is, also in this case, at the stage where a plurality of carbon nanotube fibers 2 are inserted into the pipe 3, as shown in FIG. 5A, the carbon nanotube fibers 2 have a gap in the pipe 3. Although it is inserted in a state, the pipe 3 is contracted in the radial direction by thermally contracting the pipe 3, and the carbon nanotube fiber 2 is pressed inward from the outside.
Therefore, as shown in FIG. 5B, there is no gap between the carbon nanotube fibers 2 in the pipe 3, and an inward pressing is received from the pipe 3. Therefore, by thinning the pipe 3 in this way, a state is formed in which the plurality of carbon nanotube fibers 2 are firmly gripped from the outside by the pipe 3 over the entire longitudinal direction.

In this case, it is also possible to perform a wire drawing process, an extrusion process, a rolling process, and the like.
Further, in this case, the pipe 3 and the carbon nanotube fiber 2 are configured to be thinned while moving at the same speed (that is, in a state where there is no speed difference between the pipe 3 and the carbon nanotube fiber 2).

As described above, according to the method for manufacturing the carbon nanotube element wire 1 according to the present embodiment, the pipe 3 is appropriately thinned, and the plurality of carbon nanotube fibers 2 are hardened from the outside with the pipe 3 over the entire longitudinal direction. A gripping state can be formed.
Therefore, it becomes possible to easily and accurately manufacture the carbon nanotube element wire 1 utilizing the excellent characteristics of the carbon nanotube.

[Power transmission line using carbon nanotube wire]
Next, the power transmission line 40 using the carbon nanotube element wire 1 according to the present embodiment will be described. Hereinafter, some specific examples will be described.

For example, as shown in FIG. 6A, the power transmission line 40 can be formed by twisting a plurality of carbon nanotube strands 1.
Moreover, it is also possible to form the power transmission line 40 by twisting a plurality of strands including the carbon nanotube strand 1.

In this case, for example, as shown in FIG. 6B, the carbon nanotube element wire 1 is disposed on the center side, and the periphery thereof is disposed so as to be surrounded by an element wire 41 formed of aluminum, copper, or an alloy thereof. It can be configured to twist things.
On the other hand, as shown in FIG. 7 (A), a strand 41 formed of aluminum or the like is disposed on the center side, and the one disposed so as to surround the carbon nanotube strand 1 is twisted. As shown in FIG. 7B, the power transmission line 40 can be formed by twisting a mixture of the carbon nanotube element wire 1 and the element wire 41 made of aluminum or the like.

Further, for example, as shown in FIG. 8, the carbon nanotube element wire 1 is arranged on the center side of the power transmission line 40, and the periphery thereof is surrounded by an element wire 42 formed of an aluminum-coated steel wire or a galvanized steel wire. It is possible to configure so that the arranged ones are twisted.
With this configuration, when there is a lightning strike on the transmission line 40, the lightning falls on the strand 42, and no lightning current flows directly through the carbon nanotube strand 1 inside. Therefore, with this configuration, it is possible to improve the lightning resistance (lightning protection performance) of the power transmission line 40, that is, the lightning resistance of the carbon nanotube element wire 1.

For example, it becomes possible to provide the power transmission line 40 using the carbon nanotube strand 1 which concerns on this embodiment by comprising as mentioned above.
Such a power transmission line 40 has excellent tensile strength, lighter weight, and higher electrical conductivity than the above-described ACSR, for example, due to the excellent characteristics of the carbon nanotube.

Therefore, for example, when performing the construction work of the transmission line 40 using the carbon nanotube element wire 1 according to the present embodiment, compared to the case where the above-described ACSR is stretched between steel towers, the present embodiment is concerned. In the case where the lighter transmission line 40 is stretched using the carbon nanotube element wire 1, the weight of the transmission line 40 is lighter, so that the overhead line equipment (such as a drawing car) for the overhead line is also reduced. The weight can be reduced, and the operator can perform the work easily and efficiently.
In addition, in the construction work of the transmission line 40, the construction is performed such that the pilot rope is first stretched between the steel towers, and the transmission line 40 is finally stretched after being replaced with a thicker rope. However, since the power transmission line 40 using the carbon nanotube element wire 1 according to the present embodiment is lightweight, the number of times (stages) of replacing the rope should be reduced as compared with the case where the ACSR is stretched. In addition, since the overhead wire equipment is reduced in weight, it is possible to perform the construction work of the transmission line 40 more easily and in a short time. Therefore, it is possible to shorten the construction period of the overhead wire work. This contributes to shortening the power transmission suspension period of the electric power company, which is very preferable for the electric power company.

[Example]
Here, the simulation which contrasted the characteristic of the power transmission line 40 using the carbon nanotube strand 1 which concerns on this embodiment, and ACSR is demonstrated. The simulation was performed based on JCS (Japan Electric Wire Industry Association Standard) and the like.
At that time, since there are various numerical information on various characteristics of the carbon nanotube element wire 1, the following appropriate values were set.
・ Tensile strength: 11000 MPa (= 11 GPa)
Specific gravity: 2.0 g / cm ³
・ Conductivity: 97%
-Elastic modulus: 500 GPa
・ Linear expansion coefficient: 0 / ℃

Other conditions were set as follows.
・ Ambient temperature: 40 ℃
・ Wind speed: 40m / s
・ Wind direction: 45 °
Solar radiation: 0.1 w / cm ²
-Emissivity: 0.9

なお、弛度特性は、Ｔｍａｘを２５．５ｋＮ、径間長を３００ｍとして算出した。 The simulation results are shown in Table I below.

The sag characteristics were calculated with Tmax of 25.5 kN and span length of 300 m.

As can be seen from this result, the power transmission line 40 using the carbon nanotube element wire 1 according to the present embodiment has a tensile strength of about 30 times, a mass and an electric resistance of about half, and a current capacity of about 1 compared with the ACSR. .4 times, the sag is about 60%, making it a power transmission line that takes advantage of the excellent characteristics of carbon nanotubes.
In particular, since it is possible to make the sag of about 40% smaller than the sag of the existing electric wire (ACSR) in the 300 m span length, there is no problem even if it is wired with a low tension. Therefore, for example, when constructing a new steel tower, it is possible to design the steel tower strength, members, foundation strength, etc. smaller than in the case of conventional ACSR, etc., and it is possible to reduce the cost of steel tower construction. There is also a merit of becoming.

Needless to say, the present invention is not limited to the above-described embodiment and the like, and can be appropriately changed without departing from the gist of the present invention.
Further, the carbon nanotube element wire 1 and the power transmission line 40 using the carbon nanotube element wire 1 according to the above-described embodiment can be used not only for an overhead power transmission line but also for an underground power transmission line, a submarine cable, and the like.

DESCRIPTION OF SYMBOLS 1 Carbon nanotube strand 2 Carbon nanotube fiber 2a One or several carbon nanotube fiber 3 Pipe 40 Transmission line 41, 42 Strand

Claims (12)

A carbon nanotube fiber formed only of carbon nanotubes, and a pipe,
A carbon nanotube element wire, wherein a plurality of the carbon nanotube fibers are housed in the pipe in a state in which the carbon nanotube fibers are firmly held from outside by the pipe over the entire lengthwise direction.   The carbon nanotube element wire according to claim 1, wherein the pipe is made of metal.   The carbon nanotube element wire according to claim 2, wherein the metal pipe is made of aluminum, stainless steel, copper, or an alloy thereof.   The carbon nanotube strand according to claim 1, wherein the pipe is made of a heat-shrinkable resin.   A power transmission line comprising a plurality of strands of the carbon nanotube strands according to any one of claims 1 to 4.   A power transmission line, wherein a plurality of strands including the carbon nanotube strands according to any one of claims 1 to 4 are twisted.   The power transmission line according to claim 6, wherein the element wire includes an element wire formed of aluminum, copper, or an alloy thereof.   The power transmission line according to claim 6 or 7, wherein the element wire includes an aluminum-coated steel wire or a galvanized steel wire. Inserting a plurality of carbon nanotube fibers into a metal pipe;
Thinning the pipe, forming a state in which the plurality of carbon nanotube fibers are firmly gripped from the outside with the pipe over the entire lengthwise direction;
The manufacturing method of the carbon nanotube strand characterized by including this. Inserting a plurality of carbon nanotube fibers into a heat-shrinkable resin pipe;
Shrinking the pipe by heating to form a state in which the plurality of carbon nanotube fibers are firmly gripped from the outside by the pipe over the entire longitudinal direction; and
The manufacturing method of the carbon nanotube strand characterized by including this.   11. The carbon nanotube according to claim 9, wherein the carbon nanotube fibers are bundled with one or a plurality of carbon nanotube fibers for each predetermined number before being inserted into the pipe. A manufacturing method of a strand.   The construction method of the power transmission line using the power transmission line as described in any one of Claims 5-8.

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