JPS6124891B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a closed disaster prevention trough for accommodating and laying high-voltage OF cables.

Currently, most of the important trunk lines such as ultra-high voltage OF cables installed in tunnels are housed in sealed disaster prevention troughs. It is made of reinforced plastics containing flame-retardant additives or reinforced plastics containing a large amount of glass fiber, and its fire resistance and sealing structure prevents troughs from occurring in the event of a cable ground fault. This prevented the destruction of cables and the spread of fire. However, with the recent advent of 500KV class ultra-high voltage OF cables, the arc energy in the event of a ground fault is intense, and the gas pressure within 1m of the ground fault point has become extremely strong, making it difficult for conventional sealed disaster prevention troughs to withstand the internal pressure. There is a risk of widespread disasters, such as failure to break and the cables breaking and the cables spreading.

In view of these points, the present invention quickly releases the abnormal gas pressure inside the trough that occurs during a ground fault to the outside by expanding and deforming a short lid placed over the trough body, and also quickly releases the abnormal gas pressure inside the trough to the outside after the pressure is released. The lid will immediately return to its sealed state,
The object of the present invention is to provide a disaster prevention trough that has a function of preventing abnormal gas pressure from spreading over a wide area and reliably preventing damage to the trough due to abnormal internal pressure and the spread of fire to installed cables.

Examples of the present invention will be described below with reference to the drawings.
Reference numeral 1 denotes a trough body made of flame-retardant reinforced plastic, which are connected to each other by a plug-in socket as shown in FIG. Reference numeral 2 denotes a lid body, and the lid body is made of a flame-retardant reinforced plastic with excellent elasticity in the lateral direction, such as a mat-like material made by intertwining long glass fibers, and a cloth made of glass strands woven in only one direction. It is made by stacking layers alternately in a predetermined shape to give directionality to the elasticity, and compression molding with unsaturated polyester resin added with a flame retardant such as aluminum hydroxide.The unit length of the lid body is the same as the trough body. 1, and are fixed to the trough body 1 by a method such as bolting 3 by abutting each other on the trough body 1 as shown in the figure, and the butt joints are filled with flame-retardant putty and sealed as necessary. FIG. 2 shows the lid 2.
is butted against the trough body 1 so that its upper surface 2a is normally curved inward as shown in Figure A, and bulges outward as shown in Figure B when the gas pressure in the trough increases. Another embodiment of the present invention is shown in which the cover bolt is tightened. In the figure, 4 is a cable housed in the trough.

In the trough of the present invention constructed as described above, the lid 2 placed over the flame-retardant trough main body 1 has a short unit length and excellent elasticity in the lateral direction, so the upper surface of the lid 2 covers the trough. Due to the abnormal gas pressure generated inside the lid, it bulges outward, creating a gap at the butt joint with the adjacent lid, and a large amount of gas is released from this gap. That is, the abnormal gas pressure in the trough that occurs during a ground fault reaches 10 Km/cm ² or more within 1 m of the ground fault point, but since the pressure medium is gas, the pressure attenuation in the longitudinal direction is significant. Therefore, by placing a particularly short cover 2 of unit length on the trough body 1 and covering it, the abnormal gas pressure generated at the ground fault point can be absorbed by the upper surface of the short cover 2 on the trough body located near the ground fault point. Due to the abnormal gas pressure generated, the lid body 2 instantaneously bulges and deforms greatly as shown by the dotted line in FIG. 1 (or as shown in FIG. The structure is configured so that a large amount of gas is released in a short time from As a result, it quickly returns to its original sealed state.

According to the present invention, as described above, the abnormal gas pressure inside the trough that occurs when a cable is grounded is caused by the bulging deformation of the short trough cover 2 that is butt-covered over the trough body at the ground fault point. Therefore, the pressure is quickly released to the outside, and the bulging and deformed lid body 2 restores its original sealed state due to its own elasticity, preventing outside air from entering, and there is no fear that abnormal gas pressure will spread over a wide area. Therefore, it has an excellent effect of reliably preventing damage to the trough and cable ignition and fire spread that would occur in the event of a ground fault.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the invention, and FIG. 2 is a sectional view showing another embodiment of the invention. 1: trough body, 2: lid body.

Claims (1)

[Claims] 1 A short lid body made of flame-retardant reinforced plastic that has excellent lateral elasticity and bulges outward due to abnormal gas pressure generated within the trough to create a gap between adjacent lid bodies is protruded. A closed disaster prevention trough is characterized in that it is placed over the trough body and fixed to the trough body.