JP2001076537A - Composite conductor of dissimilar material for power cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply a circular stranded wire up to the larger size by forming a strand of the outermost layer of the circular stranded wire or plural stranded layers to the inside from the outside for constituting a conductor of a power cable out of a construction material having electric conductivity higher than a strand of a layer inside of the strand. SOLUTION: A strand of a stranded wire for constituting a conductor of a power cable is formed of a copper wire 5, and a silver wire 4 having electric conductivity higher than the copper wire 5 is used for a strand of the outermost layer of the stranded wire. The silver wire 4 having high electric conductivity is used for the strand of an outside layer for flowing an electric current by a skin effect to restrain an increase in the whole apparent resistance to restrain an outer diameter increase and a cost increase, and a circular stranded wire conductor can be applied to the smaller size in a divided conductor applying area. A condition of over how many layers the strand having high electric conductivity is arranged from the outside is selected so as to optimally restrain an increase in the whole apparent resistance to obtain the same resistance as divided copper conductors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power cable conductor;

[0002]

2. Description of the Related Art In general, conductors of power cables are operated as follows. (1) Until about 800mm ²
As shown in FIG. (2) 800
In the case of the size exceeding mm ² , the supplied current becomes large, and the apparent resistance becomes large due to the so-called skin effect (the property that the alternating current tends to flow outside).
The current path is divided by using a split stranded conductor as shown in (1) to reduce the apparent resistance of the entire conductor. In FIG. 3, 1 is a strand constituting a stranded wire, and in FIG.
Reference numeral 2 denotes a strand constituting the stranded wire of the segment 3.

[0003] By the way, the twisted strands 1 and 2 described above are used.
Usually uses a copper wire. Conductivity is lower than copper, and a large size is required to carry the same current. However, aluminum wires are used in some cases because of their light weight. However, only copper is used for copper and only aluminum is used for aluminum, and there is no conductor combining these.

[0004]

As described above, 80
In order to suppress the apparent increase in resistance due to the skin effect at 0 mm ² as a boundary, a means called a divided conductor is used. However, the split conductor requires a manufacturing process of forming the segments into a stranded wire and a fan shape and twisting the segments, and thus has a disadvantage that the manufacturing cost is higher than a simple round stranded wire.

[0005] Also, in each segment of the divided conductor, a phenomenon called a skin effect seen in a circular stranded wire occurs,
This has the disadvantage that a larger size needs to be selected, which increases the outer diameter or thereby increases the cost.

Accordingly, a first object of the present invention is to provide a composite conductor of a different material for a power cable which enables the use of a circular stranded wire to a larger size and can suppress an increase in cost. A second object of the present invention is to provide a dissimilar material composite conductor for a power cable, which enables a smaller size (cross-sectional area) to be applied in a divided conductor application region and suppresses an increase in outer diameter and cost.

[0007]

In order to achieve the first object, a first means is provided for forming a conductor of a power cable by forming a plurality of twisted layers from the outermost layer or from the outer side to the inner side of a circular stranded wire. The wire is made of a material having a higher conductivity than the wire of the inner layer, thereby increasing the conductivity of the outside where current flows due to the skin effect, and increasing the overall apparent resistance. It is something that has been suppressed.

When a copper wire is used as the wire of the inner layer, a silver wire is selected as a wire of a material having high conductivity. Also,
When the element wire of the inner layer is an aluminum wire, a copper wire or a silver wire is selected as the element wire having a high conductivity.

A second means provided to achieve the second object is to form a plurality of twisted layers on the outermost layer or the outer inner side in the stranded wire of each segment of the split stranded conductor constituting the conductor of the power cable. The strand is made of a material with a higher conductivity than the inner strand, and the outer conductivity where the current tends to flow due to the skin effect in the stranded wire of each segment is increased, and the overall apparent resistance is reduced. The increase is suppressed.

When a copper wire is used as the wire of the inner layer, a silver wire is selected as a wire made of a material having high conductivity. Also,
When the wires of the inner layer are aluminum, a copper wire or a silver wire is selected as a wire of a material having high conductivity.

[0011]

FIG. 1 shows a first embodiment of a first embodiment of a composite conductor of different materials for a power cable according to the present invention; a circular stranded conductor is shown. In this first embodiment, a stranded wire constituting a conductor of a power cable is replaced with a copper wire 5.
In this case, the copper wire 5 is attached to the outermost layer of the stranded wire.
It is formed by using a silver wire 4 having higher conductivity than that of the silver wire.

As described above, by using the silver wire 4 having high conductivity as the element wire of the outer layer through which current flows due to the skin effect,
An increase in the overall apparent resistance can be suppressed, and thus an increase in the outer diameter and cost can be suppressed, which makes it possible to apply the circular stranded conductor to a smaller size (cross-sectional area) in the divided conductor application area. The notable effect is obtained.

When the circular stranded wire is mainly composed of an aluminum wire, a copper wire or a silver wire having a higher conductivity than the copper wire is used as the outermost element wire. Further, in the above embodiment, the silver wire is used only for the outermost layer. However, how many layers of such a high-conductivity element wire are provided from the outside is optimally controlled to suppress the apparent resistance increase as a whole. To choose. By the way, in the application boundary area from the round stranded wire of about 800 mm ² to the split conductor, the same as the split copper conductor by using silver wires for the outermost layer or the outer layer of the circular copper stranded wire in the layers of the plurality of layers. Resistance was obtained. The overall cost can be reduced by combining silver wires so that the increase in material costs due to the use of silver wires is smaller than the reduction in processing costs due to the omission of the divided conductor process.

FIG. 2 shows a second embodiment which embodies the second means of the dissimilar material composite conductor for a power cable according to the present invention; a split stranded conductor. In the second embodiment, a copper wire 7 is used as a stranded wire constituting each segment 8 of the divided conductor, and a silver wire having a higher conductivity than the copper wire 7 is added to the outermost strand of the stranded wire. 6 is used.

As described above, the use of the silver wire 4 having high conductivity as the element wire of the outer layer through which the current flows due to the skin effect in each segment suppresses an increase in the apparent resistance of the whole, and consequently the outer diameter. It is possible to suppress the increase in the cost and the increase in cost. This has a notable effect that a smaller size (cross-sectional area) can be applied in the divided conductor application area, and the increase in the outer diameter and the cost can be suppressed. By the way, in the divided conductor region, a conductor having a smaller size could be obtained by appropriately selecting the silver wire fee of the outer layer, and the overall cost could be reduced.

In the case where the stranded wire of the divided conductor is mainly composed of an aluminum wire, a copper wire or a silver wire having a higher conductivity than the copper wire is used for the outermost element wire of each segment. Further, in the above embodiment, the silver wire is used only for the outermost layer. However, how many layers of such a high-conductivity element wire are provided from the outside is optimally controlled to suppress the apparent resistance increase as a whole. To choose.

[0017]

As described above, according to the present invention, a first object is to provide a dissimilar material composite conductor for a power cable, which can apply a circular stranded wire to a larger size and can suppress an increase in cost. In addition, the second object of providing a heterogeneous material composite conductor for a power cable, which can apply a smaller size (cross-sectional area) in a divided conductor application region and can suppress an increase in outer diameter and cost, can be achieved. .

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional explanatory view showing a first embodiment of a first means of a dissimilar material composite conductor for a power cable according to the present invention; a circular stranded conductor.

FIG. 2 is a sectional view showing a second embodiment of the second means of the composite conductor of different materials for a power cable according to the present invention;

FIG. 3 is a partial cross-sectional explanatory view showing an example of a conventional circular stranded conductor for a power cable.

FIG. 4 is an explanatory cross-sectional view showing an example of a conventional split stranded conductor for a power cable.

[Explanation of symbols]

 4 Highly conductive outer wire; silver wire 5 inner wire; copper wire 6 Highly conductive outer wire; silver wire 7 inner wire; copper wire

Claims (6)

[Claims] An outer layer of a circular stranded wire constituting a conductor of a power cable or a wire of a plurality of stranded layers from the outside to the inside is made of a material having a higher conductivity than a wire of an inner layer. A composite conductor of different materials for power cables. 2. The dissimilar material composite conductor for a power cable according to claim 1, wherein when a copper wire is used as the wire of the inner layer, a silver wire is used as the wire of the material having high conductivity. 3. The composite conductor according to claim 1, wherein when an aluminum wire is used as the wire of the inner layer, a copper wire or a silver wire is used as the wire having a high conductivity. . 4. The conductor of a plurality of twisted layers on the outermost layer or on the inner side in the stranded wire of each segment of the split stranded conductor constituting the conductor of the power cable, is more conductive than the inner wire. Composite conductors of different materials for power cables, made of high quality materials. 5. The composite conductor for a power cable according to claim 1, wherein when a copper wire is used as the wire of the inner layer, a silver wire is used as the wire of the material having a high conductivity. 6. The composite conductor for a power cable according to claim 1, wherein when an aluminum wire is used for the wire of the inner layer, a copper wire or a silver wire is used for the wire having a high conductivity. .