| 摘要 |
PURPOSE:To enhance detection sensitivity, by a method wherein high voltage is applied between the metal part of a trouble cable and the earth, and a conductive or semiconductive liquid is scattered to the earth between two points where a voltage direction and current intensity are measured. CONSTITUTION:A cable consisting of a conductor 1, an insulator 2, a metal sheath 3 and an anticorrosion layer 4 is placed on the earth 5. This cable has a damaged part (trouble point) 41 and, when a current is supplied to the cable, a current leaks from the trouble point 41. In order to search for the trouble point 41, one terminal of a high voltage DC power source 6 is connected to the metal sheath of the cable at a certain part and the other terminal thereof is earthed. The current leaking from the trouble point 41 flows to the earth direction as a return circuit current 11. In order to measure the current 11, electrodes 8 are embedded in the earth at desired two points and a potential difference measuring voltmeter 9 is connected between both electrodes 8. At this time, brine 10 is scattered to the peripheries of the electrodes 8 to raise conductivities around the electrodes 8. Whereupon, the current 11 is concentrated at a point between the two points high in conductivity and detection sensitivity can be enhanced.
|
