JPH07131921A - Protective cover for power cable - Google Patents

Abstract

PURPOSE:To provide a protective cover for power cables that protects power cables against falling bodies and so on, and that prevents damage to secondary system cables and other lines at the occurrence of a ground fault. CONSTITUTION:A metal frame body 3 is placed above a power cable 1. The frame body 3 supports a fireproof woven fabric sheet 4 made of high-tensile strength aramid fiber, which covers the power cable 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective cover for an electric power cable which is disposed around an electric power cable laid in an underground cavern and protects the electric power cable from falling objects.

[0002]

2. Description of the Related Art FIG. 4 is a schematic view showing a conventional protective cover (protective trough) for a power cable. The support member 16 is supported by the wall 20 of the cave and extends in a substantially horizontal direction. The support members 16 are arranged in the cave at appropriate intervals. A tubular protective trough 12 is placed on the support member 16, and the protective trough 12 is restrained by a stainless band and fixed to the support member 16 by a bolt (not shown). The power cable 11 is housed in this protective trough 12. The protective trough 12 has a thickness of 3 m, for example.
m of FRP (fiber reinforced plastic) and can be divided into an upper member 12a and a lower member 12b. The upper member 12a and the lower member b are locked by the stopper 13.

[0003]

However, in the above-mentioned protective trough, when a landfall accident occurs, the protective trough is destroyed by arc energy (heat and wind pressure), and the fragments of the protective trough are scattered to cause the secondary trough. There is a problem that the system cable or other lines may be damaged.

The present invention has been made in view of the above problems, and the power cable can protect the power cable from falling objects and the like, and can prevent the secondary cable and other lines from being damaged when a landfall accident occurs. The purpose is to provide a protective cover for.

[0005]

A protective cover for a power cable according to the present invention comprises a frame body disposed above the power cable, and a woven sheet supported by the frame body and covering at least an upper portion of the power cable. And having.

[0006]

In the present invention, the woven fabric sheet is supported by the frame body disposed above the power cable, and the woven fabric sheet covers at least the upper portion of the power cable. Therefore, the woven fabric sheet can protect the power cable from a falling object and the like, and can prevent the power cable from being damaged by the falling object. In addition, when a landfall accident occurs, the wind pressure due to arc energy passes through the gaps between the fibers of the woven fabric sheet and escapes to the outside, so the cover is less likely to be damaged, and even if the cover is damaged, it will scatter. Since it is a cloth, it is possible to avoid damaging the secondary system cables and other lines.

When a sheet made of flame-retardant or fire-resistant fiber such as silica woven fiber, high-strength aramid fiber and acrylic carbonized fiber is used as the woven sheet, the power cable is protected from fire or the like. You can also
In particular, the high-strength aramid fiber is excellent in heat resistance, chemical resistance, strength and the like, and is therefore extremely suitable for a woven fabric sheet for a protective cover.

[0008]

Embodiments of the present invention will now be described with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a protective cover of a power cable according to a first embodiment of the present invention. Uprights 2 are erected at appropriate intervals in the underground cavern, and a support 6 and a direct mounting support 7 are vertically spaced apart from each other and supported by the upright 2. A cable shelf 9 is placed on the direct mounting support 7, and the power cable 1 is clamped and fixed to a clamp member 8 arranged on the cable shelf 9. A frame 3 formed of a metal angle or the like is disposed above the power cable 1 while being supported by a support member 6. The frame 3 is covered with a fireproof woven fabric sheet 4 formed of, for example, high-strength aramid fiber.
One side of the fireproof woven fabric sheet 4 hangs down to the position of the cable shelf 9 and is fixed to the frame body 3 and the cable shelf 9 by a tack or the like.

In this embodiment, since the power cable 1 is covered with the fireproof woven fabric sheet 4, the cable 1 can be protected from falling objects and the like. Further, when a landslide accident occurs, the wind pressure due to arc energy at the time of landslide escapes to the outside through the gaps between the fibers of the woven fabric sheet 4, so that damage to the woven fabric sheet 4 and the frame 3 can be suppressed. . Even if the woven fabric sheet 4 is damaged and scattered due to the wind pressure generated by the landfall accident, there is no possibility of damaging the secondary system cables and other lines because the fabric is scattered. Further, even when a fire occurs, the fire resistant woven fabric sheet 4 can suppress the spread of fire.

FIG. 2 is a sectional view showing a protective cover for a power cable according to a second embodiment of the present invention. Support 6,
Both the direct mounting support member 7 and the shelf 5 are supported by the wall 20 of the cavern, and are arranged at appropriate intervals along the longitudinal direction of the power cable 1. Three sets of the power cables 1 are placed on the direct mounting support member 7 and supported by the direct mounting support member 7. In this embodiment, since no cable rack is provided between the direct mounting support members 7, the cable 1 is slack between the direct mounting support members 7 as indicated by a chain double-dashed line in the figure. Further, similarly to the first embodiment, a frame 3 formed of a metal angle or the like is disposed above the power cable 1 while being supported by a support member 6. The frame 3 is covered with a fireproof woven fabric sheet 4, and one side of the woven fabric sheet 4 hangs down to the position of the shelf 5 below the direct mounting support 7. The woven fabric sheet 4 includes a frame body 3 and a shelf 5 by means of tacks or the like.
It is fixed to.

Also in this embodiment, similarly to the first embodiment, the power cable 1 can be protected from falling objects, fire, etc., and damage to the secondary system cables and other lines can be avoided when a landfall accident occurs. The effect can be obtained.

Next, the result of testing the cable protection function against falling objects of the cable protection cover according to the embodiment of the present invention will be described. First, a frame having a width of 30 cm, a height of 30 cm, and a length of 3 m was formed from a metal angle. Then, as shown in the schematic plan view and cross-sectional view in FIGS. 3 (a) and 3 (b), a fireproof woven fabric sheet 4 is stretched on both side portions and an upper portion of the frame body 3 to form a cable protective cover. The cover was arranged so that the power cable 1 was located at the center of the frame body 3 in the width direction.

Next, above the seat at the center of the protective cover 1
Various falling objects 10 (spanner, cleat, roller, cable bender, weight of 15 kg and weight of 20 kg) are dropped from the positions of m and 2 m, and the fireproof woven fabric sheet 4
The degree of damage was investigated. As the fire resistant woven fabric sheet 4, a sheet made of silica woven fiber, high-strength aramid fiber and acrylic carbonized fiber was used.

The characteristics of the sheet made of silica textile fiber, high-strength aramid fiber and acrylic carbonized fiber are shown in Table 1 below, and the results of the drop test are shown in Table 2 below. However, in Table 2,
When the roller was dropped from a position of 2 m, the sheet of the acrylic carbonized fiber was torn to a length of 23 mm, and the frame body was also damaged. Therefore, the subsequent tests were stopped.

[0016]

[Table 1]

[0017]

[Table 2]

As is apparent from Table 1, the woven silica fiber has the advantage of being extremely excellent in heat resistance. Further, the high-strength aramid fiber has an advantage that it is excellent in mechanical strength (tensile strength) and is also excellent in oil resistance, water resistance and chemical resistance. Furthermore, the acrylic carbonized fiber is used for preventing welding sparks from scattering, and has the advantages of good flame retardancy and low material cost.

Further, as is clear from Table 2, the woven fabric sheets of these fibers all have the effect of protecting the power cable from falling objects, and particularly in the case of high-strength aramid fibers, depending on the falling objects. Although a scratch mark was generated, the sheet was not torn, which is very suitable for a protective cover of a power cable.

[0020]

As described above, the protective cover of the power cable according to the present invention is composed of the frame body arranged above the power cable and the woven sheet supported by the frame body and covering the power cable. Therefore, it is possible to protect the power cable from falling objects, and there is little risk that the cover fragments will scatter in the event of a landfall accident, and even if the cover fragments scatter, the cloth will scatter. Therefore, there is an effect that damage to the secondary system cable and other lines can be suppressed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a protective cover of a power cable according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a protective cover of a power cable according to a second embodiment of the present invention.

3 (a) and 3 (b) are schematic plan views and cross-sectional views showing a test method of a cable protection function of a protective cover against a fallen object.

FIG. 4 is a schematic diagram showing a conventional protective cover for a power cable.

[Explanation of symbols]

 1, 11; power cable 2; upholstery 3; frame body 4; woven sheet 6,6; support material 7; direct mounting support material 9; cable shelf 12; protective trough 13; clasp

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshimi Ikegaya 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Stock Company

Claims (2)

[Claims] 1. A protective cover for a power cable, comprising: a frame body disposed above the power cable; and a woven sheet supported by the frame body and covering at least an upper portion of the power cable. 2. The protective cover for a power cable according to claim 1, wherein the woven fabric sheet is formed of high-strength aramid fiber.