Design of Polarimetric-Based Optical Current Sensor for Electric Power System Application

Abstract

Many problems arise in the electric power protection system due to applying a ferrous core current transformer (CT). One of the most crucial problems is a magnetic saturation issue, which tends to cause a measurement error on the secondary side of the CT and could reduce the performance of the protection system. An alternative solution to this issue is the needs to develop an electric current sensor utilizing optical materials. A polarimetric-based optical current sensor (OCS) is a technique considered to be compatible with the future smart grid environment. The OCS principles are based on the magneto-optic Faraday effect that could produce optical rotation in the optical media when a polarized light propagates in those materials. Due to the linear and circular birefringences effect in optical fiber medium are exist, therefore, in this paper the OCS and its associated elements are modelled by considering the birefringence effect in the optical sensor system including optical fiber links. Then, the OCS model is translated to a computer simulation program using a computer application software. Orientation of the second polarizer (analyzer) to the first polarizer in the simulation were conducted using two different angles which are angle α of 45° and 90°. Performance assessment of the OCS model is presented using two various electric current of the power system test to investigate the presence or absence of the saturation effect that may arise in the polarimetric-based optical current sensor model. The simulation results have provided that the saturation effect disappear in the simulation and the analyzer orientation angle α of 45° gives better performances of optical power modulation than the other angle.