Analysis On Rare Earth Magneto-optical Glass In Optical Current Transducer

Compared with traditional electric-magneto transformer, optical currenttransducer (OCT) has the merits of small volume, light weight and strongcompatibility with digital substation. Therefore, it has an outstanding applicationadvantage in the development of smart grid. At present, most of the OCTs usediamagnetic substance as sensing material. Paramagnetic material, which has a highmagnetic-optical sensitivity, has not gotten enough attention. As the sensing core ofOCT, magneto-optical medium is the key part limiting its performance improvement,so this thesis takes paramagnetic glass with rare earth Terbium doped as researchingsubject. The performance of paramagnetic glass with Terbium doped was researchedunder the conditions of different sizes, temperature and rare earth concentration.Basic theories of OCT were described, which were the principle of Faradaymagneto-optical effect, the generation of linear birefringence in isotropic medium,Verdet constant theory and the factors affecting magneto-optical performance ofTerbium ions doping glass. Then, based on Jones matrix, the light path model wasdeduced to get math models to analyze rare earth glass magneto-optical performance.The influence of glass size, temperature and rare earth concentration was simulatedon computer, which made a foundation for latter experiments.This thesis established a Faraday magneto-optical effect experiment system anddesigned a program with data collection and analysis with software. Two experimentsystems were also made to conduct rare earth glass temperature experiments. Withthe experiment system established, experiments were conducted to research themagneto-optical performance of rare earth glass under the condition of differentsizes, temperature and doping concentration. The influence on rare earth glassmagneto-optical sensitivity made by its size was verified. The temperaturecharacteristics of glass sensitivity and linear birefringence were analyzed byexperiments. The sensitivity and temperature characteristics of different dopingconcentration were compared as well.Besides, by experiments, this thesis compared the sensitivity, size andtemperature characteristics between rare earth glass and diamagnetic glass, ZF7. Theconclusion was gotten that rare earth glass had a higher magneto-optical sensitivitythan ZF7. The researching results of this thesis will establish a steady foundation forthe further research and application of OCT with rare earth glass as sensing material.