Magnetic field inhomogeneity induced on the magneto-optical current sensors

The growth in the capacity of electric power system creates a necessity demand on protection relaying systems. Optical current transducers (OCT) which are mainly single mode optical fiber subjected to Faraday rotation are used as replacement for EM transducers for their immunity to the EM interference. However, the sensitivity to currents depends on the Verdet constant which is low in optical fiber but the optical path length can be increased to compensate for it by winding the fiber around a current carrying element a large number of turns. In this work, we would like to study the effect of the inhomogeneity of the magnetic field induced by the current in the sensitivity of the optical fiber sensor.