OPTICAL FIBER CURRENT SENSOR AND ELECTRIC LINE MONITORING SYSTEM TO USE THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain an optical fiber current sensor capable of accurately detecting a signal current passing through an electric wire (signal electric wire) to be detected and an electric line monitoring system to use the same. SOLUTION: A converter 4 is comprised of a pair of magnetostrictive materials 5 impressed with a bias magnetic field in the same direction, an interferometer in which two arms comprised of optical fiber coils 8 are each fixed to the magnetostrictive materials 5, and a magnetic field generating coil 7 to generate a signal magnetic field in the opposite direction in the magnetostrictive materials 5. A means for detecting the phase difference of light at the interferometer is provided, in other words, a laser beam outputted from a laser beam source 13 is subjected to a phase shift proportional to a signal current at a converter 4, and the beam subjected to the phase shift is transmitted to an O/E converter 14 via an optical coupler 12 and is subjected to O/E conversion by the O/E converter 14 to obtain output proportional to the signal current from a demodulator 15.