Self-calibration and field experiments analysis of fiber-optic current sensor

All-fiber current sensors designed in Faraday principle have been widely used for monitoring and protection of smart electric network, energy conservation and energy efficiency measurement etc.; these sensors have drawn widespread attentions and researches home and abroad. However, lack of research on sensor characteristics leads that sensors´ reliabilities are sometimes difficult to meet harsh operating conditions of the industrial field. This paper introduces the structure and working principle of optical fiber current sensors in polarization reflected interferometric light-way structure. We have developed a set of optical fiber current sensors, and the influence of their linearity, the equal ampere-turn charecters and the influence of sensors´ linearity, ampere-turns and current directions to sensors´ performance has been verified in laboratory. We used the developed DC large current sensors to do site tests in the non-ferrous metal electrolytic plant. Sensors were installed at different locations of the current bus, and error of the test results is within ±0.2%. We also verified the sensor resistance to radio frequency (RF) electromagnetic radiation immunity. Experimental test data shows overall errors of optical fiber large current sensor systems can satisfy demands of site testing.