Current-Sensing Technology Using Single-Axis Polarization Encoding and Dynamically Decoding Algorithm

Traditional polarimetric current-sensing methods contain many optical devices, leading to poor reliability. Also, their sensing output is distorted by massive system noise. To address these issues, this article presents a polarimetric current-sensing method using single-axis polarization encoding (SPE) and a dynamically decoding algorithm (DDA). A single-axis circulator (SAC) and a Faraday rotator mirror (FRM) are used to encode the measured current by light. The SPE only requires these two optical devices in the light-propagation path, enhancing the measurement reliability. The encoding process can significantly suppress the noise by eliminating high-order terms. To correctly restore the current signals, the light intensity is decoded by Jones-matrix analysis and dynamic parameters. Finally, normal currents, fault currents and harmonic currents in grids are used to test the performance of the presented method. The results show that the maximum amplitude error is smaller than 1.3% in a wide range of amplitudes, frequencies, temperatures, and vibrations, and the signal-to-noise ratio and number of devices required in the path are 51.43 dB and 2, respectively (those of the recently published polarimetric method are 1.7%, −4.24 dB, and 5, respectively).