JPH0436329B

PURPOSE:To detect the fault point of a system by constituting a current transformer between conductors and finding the fracture point (fault point) on a conductor by a probe. CONSTITUTION:A magnetic bodies 11a or 11b obtained by dividing an ring- shaped magnetic body into two semicylindrical parts is wound with a coil 12 or 13 for transmission or reception. The magnetic bodies 11 and 11b are coupled in a ring shape so that an optical submarine cable penetrates their center, thus forming the current transformer 11. A pulse generator 16 is connected to the coil 12 through a power amplifier 15. Then, pulse currents are flowed through the coils 12 and 13 to generate an impulsive progressive wave in the conductors in an optical submarine cable, a pulse wave which is reflected at the fault point 21 to return is detected by the same or different coil as or from the coils 12 and 13 wound around the transformer 11, and the time that the pulse current requires to travels forth and back between the transformer 11 and fault point 21 is measured by a pulse interval counter 20, thus measuring the cable length up to the fault point 21.