JPS6260893B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a three-core type aerial conduit cable, and more particularly to a conduit aerial cable with an improved support structure for the cable conductor. As shown in Fig. 3A and B, the three-core conduit aerial cable consists of three cable conductors 1A, 1B, and 1C arranged symmetrically with respect to each other, and these three cable conductors 1A, 1B, and 1C. Sheath 2 houses three cable conductors 1A, 1B, and 1C.
It consists of an insulating spacer 3 supported within.
In the prior art, this insulating spacer 3 consists of three insulating posts 3A, 3B, 3C which separately support the three cable conductors 1A, 1B, 1C in order to save the material usage and facilitate the installation. . However, columnar spacers have weak mechanical strength, especially tensile strength, compared to compressive strength, while insulated spacers receive large tensile stress and bending stress due to electromagnetic force caused by short circuits and ground faults in cable conductors, and vibration force caused by earthquakes. receive. Figure 3A shows the electromagnetic force in the case of a 1-phase ground fault with arrows, and Figures 4A and B show the electromagnetic force in the case of a 3-phase short circuit and a 2-phase ground fault, respectively.
The electromagnetic force in the case of a phase short circuit is shown by an arrow, and FIG. 4C also shows the excitation force in the case of an earthquake by an arrow. The conditions under which these stresses are applied are summarized as shown in Table 1 below.

[Table] In the table, "pull" means tensile force, "bend" means bending force,
"Pressure" indicates compressive force. As is clear from this table, in the structure of the prior art, large tensile stress and bending stress are applied to each insulating spacer 3A, 3B, and 3C, so there is a risk of breakage. An object of the present invention is to provide an aerial conduit cable that can sufficiently withstand such electromagnetic force and excitation force. Embodiments of the present invention will be described in detail with reference to the drawings. FIGS. 1 and 2 show a conduit aerial cable 10 according to the present invention, and the conduit aerial cable 10 is arranged symmetrically with respect to each other. Three cable conductors arranged 1
It consists of cable conductors A, 1B, and 1C and a metal sheath 2 that houses these cable conductors, and the sheath 2 is filled with insulating gas. As shown in detail in FIG. 1, the insulating spacer 3 consists of three insulating rods 30A, 30B, and 30C that are integrally molded in the shape of an equilateral triangle, and the three cable conductors 1A, 1B, and 1C are connected to each other in the shape of this equilateral triangle. It is supported through the apex. This insulating spacer extends from the vertices on both sides of the base of the equilateral triangle to the insulating rods 30A, 30 corresponding to the sides on both sides of these vertices.
It has two support legs 30D and 30E that integrally extend downward so as to linearly extend C, and these support legs are fixedly attached to the inner surface of the sheath 2. The support legs 30D and 30E are set at a height such that the center of the equilateral triangle coincides with the center of the sheath 2. When the insulating spacer 3 is shaped like an equilateral triangle like this, the stress applied to the insulating spacer in the event of a ground fault, short circuit, earthquake, etc. is shared by multiple insulating rods and support legs as shown in Table 2. It turns out that it will be done. In addition, in the table, "pressure", "music" and "pu" refer to the first
Same as table.

[Table] According to the present invention, as described above, the stress applied to the insulating spacer is absorbed by the three insulating rods integrally formed in the shape of an equilateral triangle and the supporting legs extending linearly and integrally from the two insulating rods. The mechanical strength of the spacer is improved as a whole, since at least a portion of it is handled by a compressive force that is stronger than the tensile force or bending force.In addition, this insulating spacer is installed with two support legs, making it easy to install. becomes.

[Brief explanation of the drawing]

1 and 2 are a cross-sectional view and a partial longitudinal sectional view of a conduit aerial cable according to the present invention, and FIG. 3A,
B is a cross-sectional view and a partial vertical cross-sectional view of a conventional aerial pipe cable, and FIGS. 4A, B, and C are diagrams showing stress applied to the insulating spacer of a conventional air pipe cable. 10...Pipeline aerial cable, 1A, 1B, 1C
... Cable conductor, 2 ... Sheath, 3 ... Insulation spacer, 30A, 30B, 30C ... Insulation rod, 30D, 30E ... Support leg.

Claims (1)

[Claims] 1. In a conduit aerial cable consisting of three cable conductors arranged symmetrically with respect to each other, a sheath that accommodates the three cable conductors, and an insulating spacer that supports the three cable conductors within the sheath, the insulating The spacer consists of three cable insulating rods integrally molded in the shape of an equilateral triangle, the three cable conductors are supported through the vertices of the three insulating rods of the equilateral triangle, and the insulating spacer is Two insulating rods corresponding to the sides on both sides of these vertices are integrally extended in a straight line from the vertices on both sides of the base of the equilateral triangle so that the centers of the insulating rods coincide with the center of the sheath. 2 fixed to the inner surface of the sheath by
A conduit aerial cable characterized in that it has a main support leg.