JP3103518B2 - Multi-core wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-core type electric wire which is one of low-voltage overhead distribution lines which are wired between power distribution poles and supply low-voltage power to customers.

[0002]

2. Description of the Related Art At present, a multi-core electric wire is provided with two or three insulated coatings of a hard copper stranded wire or a hard aluminum stranded wire, which is not covered, as a messenger wire and a neutral conductor, and as a power line conductor. A coil in which a hard copper stranded wire or a hard aluminum stranded wire is spirally wound at an appropriate pitch is used. Normally, single-phase power is supplied when there are two power line conductors, and three-phase power or V-connection single-phase power is supplied when there are three power line conductors. For this purpose, two or three power line conductors are used. The neutral conductor is used for grounding to maintain zero voltage and for carrying an unbalanced current of the current flowing in the power line conductor (much less than the current normally flowing in the power line conductor). The messenger wire grips both ends of the electric pole and holds the entire multi-core wire imaginarily due to its tensile strength. In a multi-core electric wire, this messenger wire also serves as a neutral wire, and therefore, copper or aluminum having high conductivity is used.

[0003]

As described above, a messenger wire and a neutral conductor require high tensile strength and high electrical conductivity. For example, when employing a power line conductors of two rows of 60 mm ² hard copper stranded wire, messenger wire size required, the utility pole interval is 40 m, hard copper twisted wire 60 mm ² in terms of the required tensile strength is required. However, as described above, the current flowing through the neutral conductor is small and may be regarded as half or less of the current flowing through the power conductor. Since the required conductor size is approximately proportional to the square of the required current capacity,
Assuming that the required current capacity is の of that of the power line conductor, the size of the neutral conductor is approximately 略 of that of the power line conductor. If a hard aluminum conductor is used, the problem can be solved by using an ACSR in which an aluminum wire and a steel wire are twisted as a messenger wire and a neutral wire conductor.However, in the case of a hard copper wire, a hard copper wire and a steel wire are twisted. Matching cannot be adopted due to the problem of electric decay and the like, and as a result, a messenger wire and a neutral conductor having an unnecessarily large size are used in terms of current capacity in order to secure required tensile strength.

[0004] The influence of the large size causes a problem that not only the thick wire and the high cost but also the installation interval of the electric pole is restricted. The load F applied to the messenger wire and the neutral wire is expressed as F = KWL ² as a unit length weight W of the whole electric wire, a distance L between poles, and a proportional coefficient K.
To increase the distance L between poles while keeping F constant, it is necessary to reduce W.

Although a bare wire having no insulating coating is used as a messenger wire and a neutral conductor, the appearance is often impaired due to light reflection, uneven metallic luster, and rust. Since multi-core type electric wires are often used in places where traffic frequently occurs, such as in urban areas, it is also essential to be inconspicuous and harmonious with the environment.

[0006]

In order to solve the above-mentioned problems, in the present invention, instead of using a hard copper wire as a messenger wire and a neutral conductor, tin (Sn) whose conductivity is lowered but whose tensile strength is increased is used. ) Use copper alloy. As described above, the current of the neutral line may be considered to be less than half of the current of the power line. Therefore, if the current size is the same as that of the power line, the conductivity may be about 25%. If 2.0% by weight of tin (Sn) is blended, the conductivity of the copper alloy becomes approximately 25%, so the maximum blending ratio of tin (Sn) is 2.0% by weight. The minimum mixing ratio of tin (Sn) is set to 0.2% by weight in a range where the effect of increasing the tensile strength starts to be exhibited (securing 55 kg / mm ² or more). FIG. 1 shows changes in tensile strength and electrical conductivity of a hard copper wire containing tin (Sn).

In terms of aesthetics, the messenger wire and the neutral conductor are insulated and coated, and the color of the coating and the coating of the power line core are changed to pale gray in the range of Munsell numbers N5 / 0 to N7 / 0. Solve the problem. Light gray in the range of Munsell numbers N5 / 0 to N7 / 0 imitates the color of a cloudy sky. As a result of actual installation and evaluation in a fictitious environment, it has been confirmed that it is inconspicuous not only in cloudy weather and rainy weather but also in fine weather and in harmony with the environment.

[0008]

FIG. 4 shows the shape of a prior art multi-core electric wire, and FIG. 5 shows the cross-sectional shape of the conventional multi-core electric wire.
That is, the conventional multi-core electric wire (1) is composed of two or three insulating coatings (2) around a messenger wire / neutral conductor (2) made of a hard copper stranded wire, a hard aluminum stranded wire or an ACSR stranded wire. This is an electric wire obtained by spirally winding a power core (4) made of a hard copper stranded wire or a hard aluminum stranded wire subjected to 3) at an appropriate pitch. The identification projection (5) on the insulating coating surface of the power line core may or may not be present. Usually, black vinyl, polyethylene, ethylene propylene rubber or the like is used for the insulating coating (3) of the power line core.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to an improvement of a multi-core electric wire using a hard copper stranded wire as a messenger wire and a neutral conductor.
FIG. 2 shows a cross-sectional shape of the multi-core electric wire of the first embodiment according to the present invention, and FIG. 3 shows a cross-sectional shape of the multi-core electric wire of the second embodiment according to the present invention. The shape itself of the multi-core electric wire of the present invention is the same as or similar to the multi-core electric wire of the prior art.

In the first embodiment, a messenger wire / neutral conductor (2) is made of a twisted copper alloy containing 0.2 to 2.0% by weight of tin (Sn) and the balance essentially copper (Cu). It is a multi-core type electric wire (1) using a wire conductor. The power line core (4) is made of a hard copper stranded wire coated with an insulating coating (3), and may or may not have the identification protrusion (5) on the surface of the insulating coating (3).

In a second embodiment, a messenger wire / neutral conductor (2) is provided with an insulating coating (6), and a plurality of power lines (4) provided with the insulating coating (6) and the insulating coating (3). The multi-core electric wire (1) according to the first embodiment, characterized in that the color of the insulating coating (3) is light gray in the range of Munsell numbers N5 / 0 to N7 / 0.

[0012]

According to the present invention, the tensile strength and electric conductivity of the messenger wire and the neutral conductor are, for example, tin (S
n) When 0.6% is blended, each is 70 kg / mm
² , 60%. The tensile strength is approximately 1.5 times that of the hard copper wire, and the thickness of the messenger wire and the neutral conductor can be reduced. Although the conductivity is reduced, there is no problem in terms of required current capacity.

In the conventional multi-core electric wire having a power line core of 60 mm ² and a messenger wire / neutral conductor of 60 mm ² , the installation interval of the electric pole is at most at most due to the restriction of tensile strength. 44 m, according to the present invention (tin 0.
In the case of 6%, for example, if the size of the messenger wire and the neutral wire is kept at 60 mm ² , the size can be increased to 61 m. For example, when a multi-core type electric wire is wired in a section of 1 km, the conventional technology requires 24 power poles, whereas the present invention requires only 18 power poles. In addition, since the installation interval of electric poles can be increased, the degree of freedom of route selection is increased, and particularly when there is a place where electric poles cannot be built in the middle, it is possible to wire electric wires in one section without detouring with a plurality of electric poles.

[0014] It is also possible to overhead lines at 44m intervals by subtracting the size of the messenger wire and neutral wire conductors to 38mm ² rather than 60 mm ² in the above example. In this case, in addition to the cost reduction of the electric wire, there is an effect that the overhead wire construction becomes easier due to the weight reduction.

In the case of the second embodiment, since the surface of the electric wire has a light gray color, there is an effect that it is not conspicuous on cloudy days as well as clear days and is inconspicuous with the environment.

[0016]

[Brief description of the drawings]

FIG. 1 shows tensile strength and electrical conductivity of a hard copper wire containing tin (Sn) according to the present invention.

FIG. 2 is a sectional view of a multi-core electric wire according to the present invention (Example 1).

FIG. 3 is a sectional view of a multi-core electric wire according to the present invention (Example 2).

FIG. 4 is a configuration diagram of a conventional multi-core type electric wire.

FIG. 5 is a cross-sectional view of a conventional multi-core electric wire.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multi-core electric wire 2 Messenger wire and neutral conductor 3 Insulation coating 4 Power core 5 Identification protrusion 6 Insulation coating

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takao Katayama 1-3-1, Shimaya, Konohana-ku, Osaka-shi, Osaka Sumitomo Electric Industries, Ltd. Osaka Works (72) Inventor Shigekazu Nose 3-chome Nakanoshima, Kita-ku, Osaka-shi No. 3-22 Kansai Electric Power Co., Inc. (72) Inventor Ryuji Ito 3-22 Nakanoshima, Kita-ku, Osaka-shi Kansai Electric Power Co., Inc. (56) References JP-A-2-273012 (JP, A) JP Hei 6-330210 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 7/18 H01B 1/02

Claims (2)

(57) [Claims] An aerial power distribution multi-core electric wire comprising a plurality of insulated and covered power line conductors spirally wound at an appropriate pitch around a single messenger wire / neutral conductor. A stranded wire conductor made of a copper alloy containing 0.2 to 2.0% by weight of tin (Sn) and essentially copper (Cu) as the neutral wire conductor. Heart-shaped electric wire. 2. The insulation coating of the messenger wire and the neutral conductor, and the color of the insulation coating and the insulation coating of the plurality of power line conductors covered with the insulation are all in the range of Munsell numbers N5 / 0 to N7 / 0. 2. The multi-core wire for aerial power distribution according to claim 1, wherein the wire is light gray.