DETECTION OF ACCIDENT SECTION OF ELECTRIC POWER CABLE

摘要

PURPOSE:To detect exactly an accident section by a simple method by attaching a make and break switch for temp. detection to each cross bond wire for connecting the metallic sheath of parallel electric cables and operating the switch at the temp. of the cross bond wire or above when the electric power cables are at the max. service temp. and at the rising temp. of the cross bond wire or below when a short circuit accident arises. CONSTITUTION:A metallic sheath 3 segmented by an insulating joint 2 of the parallel electric cable 1 is connected to the metallic sheath 3 of the adjacent electric cable by means of the cross bond wire 4 and the make and break switch 5 for temp. detection is attached to each cross bond wire 4. The make and break operation of the switch 5 is so set that the heat sensitive element operates at the heated temp. of the wire 4 or above in the stage of the max. service temp. of the cable 1 and at the rising temp. of the cross bond wire 4 or below in the stage of the short circuit accident of the cable 1. The temp. of the wire 4 rises to the temp. of the cross bond wire in the stage of the max. service temp. of the cable or above when the ground-fault accident arises in some section of the cable 1 and the heat sensitive element is operated by such temp. rise, by which the switch is made or broken and the accident section is electrically detected and displayed.