JP7157632B2 - power cable - Google Patents

Description

TECHNICAL FIELD The present invention relates to a power cable capable of supplying electric power to, for example, a deep sea unmanned exploration system.

For example, when performing deep-sea exploration using an unmanned exploration system in the ocean, the unmanned exploration system connected by an underwater cable from a mother ship is launched into the sea. By using submarine cables, power and signals can be sent from the mother ship to the unmanned exploration system.

Since such an undersea cable requires a predetermined axial force, it is provided with an armor made of a tensile strength member. The sheath is provided, for example, in two layers on the outer periphery of the core wire for electric power. The tensile members of each layer are arranged in opposite directions with a predetermined twist pitch (for example, Patent Document 1).

JP 2009-199847 A

However, for example, an undersea cable (umbilical cable) that connects an undersea diving robot and an offshore base is always under tension due to its own weight, waves, tidal currents, etc., and torque is generated in the undersea cable due to the tension. Therefore, force is applied to the submarine cable so that the entire cable is twisted. In general, power cable cores and communication cable cores are prone to damage due to twisting, which often results in loss of transmission function.

In particular, umbilical cables are often used by pulling out long-distance cables from offshore bases to underwater robots, and are more susceptible to twisting due to underwater disturbances than other cables. Furthermore, if the tension is loosened in such a twisted state, a loop is generated at the relevant location, and if the tension is applied again in the looped state, the loop diameter may shrink and a kink may occur.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power cable that is less prone to kink even if a loop is formed due to twisting.

In order to achieve the above object, the present invention is a power cable comprising an electric wire, a tensile strength member arranged along the electric wire, and a protective layer collectively covering the electric wire and the tensile strength member. Therefore, it is desirable that the ratio of the minimum bending stiffness to the maximum bending stiffness in the direction perpendicular to the axial direction of the power cable is 2 or more at any position in the axial direction.

The power cable is an undersea cable, the tensile strength member is a plurality of wire rods, and the wire rods are arranged on the outer circumference of the wire at a predetermined twist pitch.

Further, among the plurality of wires arranged in the circumferential direction, high-rigidity wires having relatively high rigidity relative to the wires at other positions are arranged at predetermined angles in the circumferential direction .

The high-rigidity wire may be different in material from the other wires. In this case, it is desirable that the high-rigidity wire is a steel wire and the other wire is a resin fiber body.

The high-rigidity wire may have a cross-sectional shape different from that of the other wire. In this case, the high-rigidity wire preferably has a substantially rectangular cross section.

Among the plurality of wire rods arranged in the circumferential direction, a plurality of the wire rods adjacent to each other may be connected at every predetermined angle in the circumferential direction. In this case, the predetermined angle is preferably 120 degrees or 180 degrees.

Among the plurality of wires arranged in the circumferential direction, the wires may be adhered to the protective layer at predetermined angles in the circumferential direction.

According to the present invention, since the bending rigidity in the direction perpendicular to the axial direction of the power cable has anisotropy depending on the bending direction, even if the tension is loosened and a loop is formed, even if the tension is generated again, the kink will occur. can be suppressed.

Such effects can be effectively obtained particularly when the ratio of the minimum bending rigidity to the maximum bending rigidity in the bending direction of the power cable is 2 or more.

As such a power cable, it can be applied to an undersea cable in which the tensile member is composed of a plurality of wire rods, and the wire rods are arranged on the outer circumference of the wire at a predetermined twist pitch.

Further, among the plurality of wires arranged in the circumferential direction, by arranging high-rigidity wire rods at predetermined angles in the circumferential direction, anisotropy in the bending direction can be easily obtained.

In this case, by making the material of the high-rigidity wire different from that of the other wires, it is possible to easily obtain anisotropy depending on the bending direction. For example, a steel wire can be applied as the high-rigidity wire, and a resin fiber body can be applied as the other wire.

Similarly, by making the cross-sectional shape of the high-rigidity wire rod different from the cross-sectional shape of the other wire rods, it is possible to easily obtain anisotropy depending on the bending direction. For example, the high-rigidity wire can have a substantially rectangular cross section, and the other wire can have a substantially circular cross section.

Anisotropy in the bending direction can also be obtained by connecting a plurality of adjacent wire rods among the plurality of wire rods arranged in the circumferential direction at predetermined angles in the circumferential direction. For example, by connecting a plurality of adjacent wires at every angle of 120 degrees or 180 degrees, anisotropy of bending rigidity can be efficiently obtained.

Anisotropy depending on the bending direction can also be obtained by adhering the wire rods and the protective layer at predetermined angles in the circumferential direction among the plurality of wire rods arranged in the circumferential direction.

ADVANTAGE OF THE INVENTION According to this invention, even if a loop arises by twisting, the power cable which a kink cannot generate easily can be provided.

Sectional drawing which shows the power cable 1. FIG. FIG. 2 is a diagram showing an example of a usage state of the power cable 1; Sectional drawing which shows the power cable 1a. Sectional drawing which shows the power cable 1b. Sectional drawing which shows the power cable 1c. Sectional drawing which shows 1 d of power cables. Sectional drawing which shows the power cable 1e. Sectional drawing which shows 1 f of electric power cables. (a) to (d) are diagrams showing a test method for a specimen 30. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the power cable 1. FIG. The power cable 1 is mainly composed of an electric wire 9, an optical cable 11, a tension member 21, an inner sheath 17, a protective layer 19, and the like. The illustrated example shows an example in which three electric wires 9, two optical cables 11, and one grounding wire 13 are arranged. It is not particularly limited.

The electric wire 9, the optical cable 11, and the ground wire 13 are bundled and covered with an inner sheath 17 collectively. The inner sheath 17 is a resin layer having flexibility and impermeability, and is made of polyethylene, for example. A space within the inner sheath 17 other than the electric wire 9 , the optical cable 11 and the ground wire 13 is filled with silicon 15 .

A tensile member 21 is arranged along the wire 9 and the like on the outer circumference of the inner sheath 17 . The tensile strength member 21 is composed of a plurality of wire rods 21a, 21b, etc., and the wire rods 21a, 21b are arranged on the outer periphery of the electric wire 9, etc. (outer periphery of the inner sheath 17) at a predetermined twist pitch. Wire rods 21a and 21b are arranged in two layers in the tensile member 21, and the inner wire rod 21a and the outer wire rod 21b are twisted in opposite directions. Details of the tensile strength member 21 will be described later.

The tensile members 21 including the electric wires 9 and the like and arranged on the outer periphery thereof are collectively covered with the protective layer 19 . The protective layer 19 is for protecting the tension member 21 from the outside, and is composed of, for example, a braided tube woven with Tetoron yarn. The power cable 1 has flexibility as a whole.

Next, the tensile strength member 21 of the power cable 1 will be described in detail. As described above, the tensile member 21 is composed of two layers. The inner side of the tensile strength member 21 is composed of a wire rod 21a, and the outer side of the tensile strength member 21 is composed of a wire rod 21b and a high-rigidity wire rod 21c.

The wires 21a and 21b are made of, for example, a fiber resin (FRP). The high-rigidity wire 21c is, for example, a steel wire. That is, the high-rigidity wire rod 21c is different in material from the other wire rods 21a and 21b, and is relatively rigid with respect to the other wire rods 21a and 21b.

The high-rigidity wire rods 21c are arranged in place of the wire rods 21b at every predetermined angle in the circumferential direction with respect to the plurality of wire rods 21b arranged in the circumferential direction. In the illustrated example, the high-rigidity wire rods 21c are arranged every 180° in the circumferential direction. In this manner, by arranging the high-rigidity wire rods 21c at predetermined angles in the circumferential direction of the tensile strength member 21, the bending rigidity of the power cable 1 can be changed depending on the bending direction. That is, at any position in the axial direction of the power cable 1, the bending stiffness in the direction perpendicular to the axial direction of the power cable 1 has anisotropy depending on the bending direction.

For example, in the illustrated example, this is the direction in which the bending of the high-rigidity wire 21c with high bending rigidity increases, which is the direction in which the bending rigidity in the Y direction of the power cable 1 increases and the bending of the high-rigidity wire 21c decreases. The bending rigidity of the power cable 1 in the X direction is lowered.

Here, the fact that the bending stiffness in the direction perpendicular to the axial direction of the power cable has anisotropy depending on the bending direction means that three-point bending (for example, JIS K7171) is performed at each predetermined angle with respect to the circumferential direction, It means that the bending stiffness changes periodically depending on the direction of bending. In addition, it is desirable that the ratio of the minimum bending rigidity to the maximum bending rigidity in the bending direction of the power cable 1 is 2 or more. If the bending rigidity ratio is sufficient, it is possible to effectively suppress the occurrence of kinks. Moreover, it is desirable that the ratio of the minimum bending rigidity to the maximum bending rigidity in the bending direction of the power cable 1 is 12 or less. If the flexural rigidity ratio is too high, the handleability will deteriorate.

Next, an example of how to use the power cable 1 will be described. FIG. 1 is a conceptual diagram showing an example of how to use the power cable 1. As shown in FIG. In the figure, illustration of cables other than the power cable 1 is omitted. The power cable 1 can be used, for example, as an undersea cable.

A power cable 1 is drawn out into the sea from a mother ship 3 on the ocean through a sheave. The tip of the power cable 1 is connected to the submarine 5 , and the submarine 5 is connected to the probe 7 via the power cable 1 . Power and signals can be sent from the mothership 3 to the submersible 5 and the probe 7 via the power cable 1 .

As described above, the power cable 1 may be twisted when it is paid out or subjected to tension. In particular, when the power cable 1 is used as shown in FIG. 1, repeated forces are applied to the power cable 1 by waves and ocean currents. Therefore, when the tension is relaxed, a loop is formed by twisting, and when the tension is applied again, the loop may not return to its original state, resulting in a kink. When a kink occurs, it becomes a cause of disconnection of an internal electric wire or the like. Therefore, it is necessary to suppress the occurrence of kinks.

The inventors investigated the mechanism of kink generation, and found that when the bending rigidity of the power cable 1 is anisotropic, it is effective in suppressing the kink generation. That is, when the tension is loosened in the twisted power cable 1, a loop is formed, and when the tension is applied again, the loop becomes small in diameter and becomes a kink if it is localized. It has been found that if the power cable 1 has a portion that is difficult to bend at a stage where it becomes smaller, the loop becomes easier to return to its original state.

In addition, if the bending rigidity is high in all directions, the handleability is also deteriorated. As in the present embodiment, by forming an easy-to-bend direction and a hard-to-bend direction, the handleability is excellent and the occurrence of kinks can be efficiently suppressed.

As described above, according to the present embodiment, the bending rigidity of the power cable 1 is anisotropic depending on the bending direction, so the occurrence of kinks can be suppressed.

Moreover, by using a high-rigidity wire rod 21c made of a different material in place of the wire rod 21b in a part of the tensile strength member 21, an anisotropic bending rigidity can be obtained, so that a special manufacturing process is not required. For example, if the outer diameters of the wire 21b and the high-rigidity wire 21c are substantially the same, the power cable 1 can be easily manufactured by a conventional power cable manufacturing process.

In addition, the range in which the high-rigidity wire 21c is arranged is not particularly limited. For example, in the illustrated example, the three adjacent high-rigidity wires 21c are replaced with the wires 21b, but more wires 21b may be replaced with the high-rigidity wires 21c. For example, the number of high-rigidity wires 21c may be greater than that of wires 21b. In this case, among the plurality of high-rigidity wires 21c arranged in the circumferential direction, the wires 21b with relatively low rigidity are arranged at every predetermined angle in the circumferential direction. However, also in this case, it is one aspect of the present embodiment in which the high-rigidity wire rods 21c are arranged at predetermined angles in the circumferential direction.

Next, a second embodiment will be described. FIG. 3 is a cross-sectional view of a power cable 1a according to the second embodiment. In addition, in the following description, the same reference numerals as in FIG. 1 are given to the components having the same functions as those of the power cable 1, and overlapping descriptions are omitted.

The power cable 1a has substantially the same configuration as the power cable 1, but differs in the configuration of the high-rigidity wire 21c. The high-rigidity wire rod 21c of the power cable 1a has a different cross-sectional shape from the other wire rods 21b. In the illustrated example, the high-rigidity wire rod 21c has an elongated shape (for example, a substantially rectangular shape) in cross section as opposed to the wire rod 21b, which has a substantially circular cross-section. larger than the outer diameter. The wire 21b and the high-rigidity wire 21c may be made of the same material (for example, FRP), or may be made of different materials as in the first embodiment.

Here, the high-rigidity wire 21c has different bending rigidity in the direction of the minor axis (thickness direction) and bending rigidity in the direction of the major axis (width direction), and the bending rigidity in the major axis direction is greater than the bending rigidity in the minor axis direction. Also, the high-rigidity wires 21c are arranged at positions facing each other with their major and minor axes oriented in the same direction. Therefore, the power cable 1a has low flexural rigidity in the X direction in which the high-rigidity wire 21c is easy to bend, and has high flexural rigidity in the Y-direction in which the high-rigidity wire 21c is difficult to bend. That is, at any position in the axial direction of power cable 1a, the bending stiffness in the direction perpendicular to the axial direction of power cable 1a has anisotropy depending on the bending direction.

According to the second embodiment, effects similar to those of the first embodiment can be obtained. In this manner, by arranging the high-rigidity wire rods 21c having a bending direction in which the bending rigidity is higher than that of the wire rods 21b at predetermined angles in the circumferential direction of the power cable 1a, the bending rigidity of the power cable 1a varies depending on the bending direction. Anisotropy can be produced.

Next, a third embodiment will be described. FIG. 4 is a cross-sectional view of a power cable 1b according to the third embodiment. The power cable 1b has substantially the same configuration as the power cable 1, but differs in that the tensile member 21 is composed only of the wires 21a and 21b.

In the power cable 1b, among the plurality of wires 21b arranged in the circumferential direction, the plurality of adjacent wires 21b are connected by the connecting member 23 at every predetermined angle (180° in the figure) in the circumferential direction. The connecting material 23 may be a bundle material, or may be an adhesive that bonds the wires 21b together. By doing so, the connected wires 21b are integrated and become less likely to be displaced from each other.

Therefore, the power cable 1b has low bending rigidity in the X direction in which the connected wires 21b tend to bend, and high bending rigidity in the Y direction in which the connected wires 21b do not bend easily. That is, at any position in the axial direction of the power cable 1b, the bending rigidity of the power cable 1b can be anisotropic depending on the bending direction.

According to the third embodiment, effects similar to those of the first embodiment can be obtained. By connecting the wire rods 21b in this manner, the same effect as that obtained by arranging the high-rigidity wire rods 21c can be obtained. By connecting the adjacent wires 21b to each other, for example, every 120 degrees or every 180 degrees, the anisotropy of the flexural rigidity can be efficiently obtained.

Next, a fourth embodiment will be described. FIG. 5 is a cross-sectional view of a power cable 1c according to the fourth embodiment. The power cable 1 c has substantially the same configuration as the power cable 1 , but differs in that a portion of the wire 21 b is adhered to the protective layer 19 .

In the power cable 1c, among the plurality of wires 21b arranged in the circumferential direction, some wires 21b are adhered to the protective layer 19 and the adhesive 25 at every predetermined angle (180° in the figure) in the circumferential direction. . By doing so, the bonded wire rod 21b is prevented from being displaced with respect to the protective layer 19, so that the protective layer 19 suppresses bending.

Therefore, the power cable 1c originally has low flexural rigidity in the X direction, in which displacement between the bonded wire rod 21b and the protective layer 19 is difficult to occur, and displacement between the bonded wire rod 21b and the protective layer 19 is likely to occur. In the Y direction, the bending rigidity increases. That is, at any position in the axial direction of the power cable 1c, the bending rigidity of the power cable 1c can be anisotropic depending on the bending direction.

According to the fourth embodiment, effects similar to those of the first embodiment can be obtained. By adhering a part of the wire 21b to the protective layer 19 in this manner, the same effect as that obtained by arranging the high-rigidity wire 21c can be obtained.

Next, a fifth embodiment will be described. FIG. 6 is a cross-sectional view of a power cable 1d according to the fifth embodiment. The power cable 1d has substantially the same configuration as the power cable 1, but differs in that the outer shape of the power cable 1d is non-circular. Since the power cable 1d has an oval shape, the flexural rigidity differs between the major axis direction and the minor axis direction.

In the power cable 1d, the inner sheath 17 has a non-circular outer shape, but it is not limited to this. Further, like the power cable 1e shown in FIG. 7, an outer cover 27 having a non-circular outer shape may be arranged around the outer periphery of the substantially circular power cable to make the whole cable non-circular. In this case, the protective layer 19 may be eliminated and the external cover 27 may function as a protective layer.

The power cables 1d and 1e have different flexural rigidity in the major axis direction and the minor axis direction. That is, the power cable 1d has low bending rigidity in the X direction, which is the short axis direction, which is easy to bend, and high bending rigidity in the Y direction, which is the long axis direction, which is hard to bend. In this manner, anisotropy in the bending direction can be generated in the bending stiffness of the power cables 1d and 1e at any position in the axial direction of the power cables 1d and 1e.

According to the fifth embodiment, effects similar to those of the first embodiment can be obtained. In this way, by making the outer shape non-circular and providing the major axis direction and the minor axis direction, it is possible to generate anisotropy in the bending rigidity of the power cables 1d and 1e depending on the bending direction.

Next, a sixth embodiment will be described. FIG. 8 is a cross-sectional view of a power cable 1f according to the sixth embodiment. The power cable 1f is not an underwater cable, but a power cable used on the ground.

The power cable 1f is composed of slots 29, electric wires 9, tensile members 21, protective layers 19, and the like. Grooves are formed on the outer circumference of the slot 29 at predetermined intervals in the circumferential direction, and the electric wires 9 are accommodated in the respective grooves. An optical cable or the like may be arranged instead of a part of the electric wire 9 .

A protective layer 19 is formed on the outer circumference of the slot 29 by pressing or the like. The protective layer 19 is made of resin, for example. A tensile member 21 is embedded in the protective layer 19 . A pair of tensile members 21 are arranged at positions facing each other across the center of the cable.

The power cable 1 f has different flexural rigidity in the bending direction depending on the arrangement of the tensile members 21 . That is, the power cable 1f has low flexural rigidity in the Y direction, in which the tensile member 21 tends to bend, and has high flexural rigidity in the X direction, in which the tensile member 21 does not easily bend. In this manner, anisotropy can be generated in the bending rigidity of the power cable 1f depending on the bending direction at any position in the axial direction of the power cable 1f.

According to the sixth embodiment, effects similar to those of the first embodiment can be obtained. Thus, the power cable of the present invention can be applied to other than submarine cables.

Various power cables were evaluated for kinking susceptibility. The cross-sectional structure of the specimen to be tested was substantially the same as that of the power cable 1a, the material of the inner sheath 17 was polyethylene, and the outer diameter was 19.2 mm. As the tensile strength member 21, the material is FRP, and a high-rigidity wire rod having a substantially rectangular cross section is partially arranged. The protective layer 19 is a braided tube made of Tetoron yarn and has an outer diameter of 29 mm.

First, the bending stiffness in the direction of minimum bending stiffness (X direction in FIG. 3) and the bending stiffness in the direction of maximum bending stiffness (Y direction in FIG. 3) were measured. The bending stiffness was evaluated according to JIS K7171. More specifically, the bending speed was set to 0.5 mm/min, the tester load point R was set to 5R, and the receiving jig was made of chamfered metal. The distance between fulcrums was 110 mm.

When the ratio of maximum bending stiffness/minimum bending stiffness measured as described above was calculated, it was possible to change the bending stiffness ratio by changing the size and shape of the high-rigidity wire.

Next, the bending stiffness ratio was changed to evaluate the susceptibility to kink generation. Evaluation was performed by simulation using beam elements. With a wire length of 9 m, using the physical properties of iron (Young's modulus 210 GPa, Poisson's ratio 0.3, strain 0.03 at 1570 MPa on the ss curve), and changing the dimensions with a rectangular cross section, the anisotropic bending rigidity in the vertical and horizontal directions got sex.

In the simulation, first, as shown in FIG. 9(a), both ends of a specimen 30 having an initial length L were fixed and straightened. Next, as shown in FIG. 9B, one end of the test piece 30 is moved by 5% of the wire length L toward the other end (arrow B in the drawing), and one end of the test piece 30 is The ends were twisted at a predetermined angle (arrow A in the figure).

Next, as shown in FIG. 9(c), one end side of the test body 30 was moved to the other end side of the test body 30 by 75% of the wire length L (arrow B in the figure). That is, the tension on the specimen 30 was relaxed. At this time, a loop was formed in the specimen 30 when the torsion angle exceeded a predetermined value.

Next, as shown in FIG. 9(d), when one end of the specimen 30 is returned to its original position (arrow C in the figure), when the twist angle is greater than or equal to a predetermined value, the loop is A kink occurred without being resolved. The above test was performed with different twisting angles, and the minimum twisting angle at which kink occurred was determined. Table 1 shows the results.

The torsion angle was calculated as a ratio based on the calculation result when the flexural rigidity was not anisotropic. From the results, it can be seen that the larger the bending rigidity ratio, the larger the torsion angle at which kink occurs, and the less kink occurs. In particular, in terms of calculation, the effect could be confirmed when the bending rigidity ratio was 2 or more.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical scope of the present invention is not influenced by the above-described embodiments. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. be understood to belong to

For example, in each of the above-described embodiments, in order to obtain the anisotropy of the bending rigidity in the bending direction, anisotropic wires such as the high-rigidity wire 21c and the connecting member 23 are placed at 180° positions in the circumferential direction of each power cable. This angle is not particularly limited, although the configuration that is the factor has been arranged. That is, the bending direction in which the minimum bending rigidity and the bending direction in which the maximum bending rigidity are obtained do not have to be perpendicular to each other. For example, the high-rigidity wire rods 21c and the like may be arranged at intervals of 120°.

1, 1a, 1b, 1c, 1d, 1e, 1f …… Power cable 3 …… Mother ship 5 …… Submarine 7 …… Surveyor 9 …… Electric wire 11 …… Optical cable 13 …… Grounding Wire 15 Silicon 17 Inner sheath 19 Protective layer 21 Tensile member 21a, 21b Wire rod 21c Highly rigid wire rod 23 Coupling material 25 Adhesive 27 …… Outer cover 29 …… Slot 30 …… Specimen

Claims (8)

an electric wire;
a strength member disposed along the wire;
a protective layer that collectively covers the electric wire and the tensile strength member;
A power cable comprising
At any position in the axial direction, the ratio of the minimum bending stiffness to the maximum bending stiffness with respect to the direction perpendicular to the axial direction of the power cable is 2 or more ,
The power cable is an undersea cable,
The tensile strength member is a plurality of wires, and the wires are arranged on the outer circumference of the electric wire at a predetermined twist pitch,
An electric power characterized in that, of the plurality of wires arranged in the circumferential direction, high-rigidity wires having relatively high rigidity with respect to the wires at other positions are arranged at predetermined angles in the circumferential direction. cable. 2. The power cable according to claim 1 , wherein said high-rigidity wire is different in material from said other wires. 3. The power cable according to claim 2 , wherein said high-rigidity wire is a steel wire, and said other wire is a resin fiber body. 2. The power cable according to claim 1 , wherein the high-rigidity wire has a cross-sectional shape different from that of the other wires. 5. The power cable according to claim 4 , wherein the highly rigid wire has a substantially rectangular cross section. an electric wire;
a strength member disposed along the wire;
a protective layer that collectively covers the electric wire and the tensile strength member;
A power cable comprising
At any position in the axial direction, the ratio of the minimum bending stiffness to the maximum bending stiffness with respect to the direction perpendicular to the axial direction of the power cable is 2 or more,
The power cable is an undersea cable,
The tensile strength member is a plurality of wires, and the wires are arranged on the outer circumference of the electric wire at a predetermined twist pitch,
A power cable, wherein a plurality of adjacent wires among the plurality of wires arranged in the circumferential direction are connected at predetermined angles in the circumferential direction. 7. The power cable according to claim 6 , wherein said predetermined angle is 120 degrees or 180 degrees. an electric wire;
a strength member disposed along the wire;
a protective layer that collectively covers the electric wire and the tensile strength member;
A power cable comprising
At any position in the axial direction, the ratio of the minimum bending stiffness to the maximum bending stiffness with respect to the direction perpendicular to the axial direction of the power cable is 2 or more,
The power cable is an undersea cable,
The tensile strength member is a plurality of wires, and the wires are arranged on the outer circumference of the electric wire at a predetermined twist pitch,
A power cable, wherein said wire rods are adhered to said protective layer at every predetermined angle in said circumferential direction among said plurality of said wire rods arranged in said circumferential direction.

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