JPH0998528A - Multiple-conductor transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the increase in the looseness by locating a conductor of a small coefficient of linear expansion above the one which has a large coefficient of linear expansion and holding each conductor with spasers which are installed at regular intervals. SOLUTION: A conductor 10 of a small coefficient of linear expansion is located at the upper side and a conductor 20 of a larger coefficient of linear expansion is located at the lower side. Each of the conductors 10, 20 is held by spacers 30 which are installed at regular intervals in the longitudinal direction. Each spacer 30 consists of a frame 31 and conductor holding sections 32 which are project-formed on the frame 31. When power is transmitted through this multiple-conductor transmission line, the conductor 10 expands only a little and there is a small increase in the looseness, however the conductor 20 expands much and there is much increase in the looseness. Therefore, these two conductors come to a state that the conductor 20 is hung from the conductor 10. By this method, the increase in the looseness of the entire line can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiconductor transmission line in which one phase is composed of a plurality of conductors.

[0002]

2. Description of the Related Art With the increase in power transmission capacity in recent years, multi-conductor power transmission lines in which one phase is composed of a plurality of conductors, for example, four conductors, six conductors, eight conductors, etc. are often used.

Conventionally, conductors having the same coefficient of linear expansion have been used as the plurality of conductors constituting the above-mentioned multiconductor power transmission line. That is, for example, in a four-conductor power transmission line, four steel-core aluminum twisted wires formed by twisting aluminum element wires on a steel core formed by twisting steel wires are used.

When a steel-core aluminum stranded wire is used as the conductor, the steel-core aluminum stranded wire has a large linear expansion coefficient, and since the sag increases as the transmission capacity increases, the linear expansion coefficient is changed to a steel wire. There is also a case where an invar electric wire is used in which a small invar wire is twisted to form a core material, and a heat-resistant aluminum wire is twisted around the core material. Four such invar electric wires were used if they were four conductor transmission lines.

[0005]

SUMMARY OF THE INVENTION As described above, conventionally,
A conductor having the same linear expansion coefficient was used for all of the plurality of conductors forming the multi-conductor transmission line. For this reason, in a conductor having a large linear expansion coefficient, when the power transmission capacity is increased, the sag is also increased, and therefore, there is a problem that the power transmission capacity is limited in order to keep the sag increase constant. It was Further, in a conductor having a small linear expansion coefficient, the sag increase can be suppressed, but there is a problem that it is expensive.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an inexpensive multi-conductor power transmission line capable of suppressing an increase in sag and increasing a power transmission capacity. In the multi-conductor transmission line in which one phase is composed of a plurality of conductors, the plurality of conductors are composed of a conductor having a small linear expansion coefficient and a conductor having a large linear expansion coefficient. It is characterized in that a conductor having a small coefficient is arranged above a conductor having a large linear expansion coefficient, and each conductor is held by a spacer at regular intervals.

By arranging a conductor having a small coefficient of linear expansion above a conductor having a large coefficient of linear expansion and holding each conductor by a spacer at regular intervals, the conductor having a small coefficient of linear expansion does not expand during power transmission. Although it is small and the sag increase is small, a conductor having a large linear expansion coefficient has a large elongation and a large sag increase. Therefore, a conductor having a large linear expansion coefficient is suspended from a conductor having a small linear expansion coefficient. Therefore, the increase in the sag of the conductor having a large linear expansion coefficient does not directly increase the sag of the multi-conductor transmission line, and the increase in the sag of the multi-conductor transmission line as a whole can be suppressed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. 1 and 2 show a case where the multiconductor power transmission line according to the present invention is applied to a four conductor power transmission line. In this multiconductor transmission line, the conductor 10 having a small linear expansion coefficient is arranged on the upper side, and the conductor 20 having a large linear expansion coefficient is arranged on the lower side. The conductors 10 and 20 are held by the spacer 30 at regular intervals in the longitudinal direction. As the conductor 10 having a small linear expansion coefficient, for example, an Invar electric wire formed by twisting a heat-resistant aluminum wire or the like on the outer periphery of a core material formed by twisting an Invar wire is used. A steel-core aluminum stranded wire made by twisting aluminum element wires around the outer circumference of the core material is used. The spacer 30 is composed of a frame 31 and a conductor gripping portion 32 formed so as to project from the frame.

When power is transmitted to the multi-conductor transmission line having the above structure,
The conductor 10 having a small linear expansion coefficient has a small elongation and a small sag increase, but the conductor 20 having a large linear expansion coefficient has a large expansion and a large sag increase. For this reason, as shown in FIG. 3, the conductor 10 having a small linear expansion coefficient is changed to the conductor 20 having a large linear expansion coefficient.
Are suspended via the spacer 30. Therefore, it is possible to suppress an increase in the sag of the entire multiconductor transmission line.

The conductor 10 having a small coefficient of linear expansion is not limited to an invar wire formed by twisting an invar wire as a core material and twisting a heat resistant aluminum wire or the like around the core material. For example, only an invar wire is twisted. Invar stranded wire, an electric wire in which carbon fiber is used for the core material and aluminum wires are stranded on the outer periphery,
An electric wire in which polyparaphenylene benzobisoxazole fiber is used as the core material and an aluminum wire or the like is twisted around the outer circumference thereof, or a wire in which Kepler is used as the core material and an aluminum wire or the like is twisted around the outer circumference thereof can be used.

Further, the conductor 20 having a large linear expansion coefficient is not limited to the steel core aluminum stranded wire, and for example, an aluminum electric wire in which aluminum wires are twisted, a copper electric wire in which copper wires are twisted and the like can be used.

Since the conductor 10 having a small linear expansion coefficient and the conductor 20 having a large linear expansion coefficient are relative to each other, for example, a steel core aluminum stranded wire and an aluminum stranded wire are used. When constructing an overhead power transmission line, a steel-core aluminum stranded wire serves as the conductor 10 having a small linear expansion coefficient, and an aluminum-based stranded wire serves as a conductor 20 having a large linear expansion coefficient.

Further, what kind of electric wire is used as the conductor 10 having a small linear expansion coefficient and what kind of electric wire is used as the conductor 20 having a large linear expansion coefficient is determined by the transmission capacity and the sag characteristic of the line. It is decided in consideration.

The multiconductor transmission line according to the present invention is
It can be applied not only to a four-conductor power transmission line, but also to a two-conductor, three-conductor, six-conductor, eight-conductor, etc. power transmission line.

[0015]

As described above, in the multi-conductor transmission line according to the present invention, a plurality of conductors are composed of a conductor having a small linear expansion coefficient and a conductor having a large linear expansion coefficient. Since the conductors are arranged above the conductor with a large linear expansion coefficient and the conductors are held by the spacers at regular intervals, when the power is transmitted, the conductor with a large linear expansion coefficient is suspended from the conductor with a small linear expansion coefficient. . Therefore, the increase in the sag of the conductor having a large linear expansion coefficient does not directly increase the sag of the multi-conductor transmission line, and the increase in the sag of the multi-conductor transmission line as a whole can be suppressed. Therefore, it is possible to increase the transmission capacity. Further, since it is generally less expensive to use a conductor having a small linear expansion coefficient, there is an effect of being inexpensive.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is an explanatory diagram showing a usage state of the present invention.

[Explanation of symbols]

 10 conductor with small linear expansion coefficient 20 conductor with large linear expansion coefficient 30 spacer

Claims (1)

[Claims] 1. In a multi-conductor transmission line in which one phase is composed of a plurality of conductors, the plurality of conductors are composed of a conductor having a small linear expansion coefficient and a conductor having a large linear expansion coefficient, A multi-conductor power transmission line characterized in that a conductor having a small linear expansion coefficient is arranged above a conductor having a large linear expansion coefficient, and each conductor is held by a spacer at regular intervals.