Digital electric current measuring system with fiber optical sensitive element

Abstract

The relevance of the present work on the creation of a digital system for measuring the magnitude of the electric current with a fiber-optic sensitive element in the form of a magneto-optical Faraday cell from a polarization-preserving optical fiber with linear birefringence rolled into a coil inside which a current conductor is located is substantiated.The goal of the work was formulated as the development of a new optoelectronic measuring system for measuring electric current, based on the Faraday magneto-optical effect in optical fiber and containing modern digital components in its structure.Based on the analysis of foreign and domestic patent and scientific and technical literature, it was revealed that the most promising direction of development is the use of a sensitive element of the measuring system in the form of a fiber optic coil, in which the measurement process is based on the Faraday magneto-optical effect. This allows to obtain high quality indicators, such as the ability to measure variable and constant currents: error ± 0.1%; repeatability of characteristics from sample to sample ± 0.02%; linearity ± 0.1%; dynamic range > 4 kHz, temperature sensitivity <± 0,002%/°С; the mass of the sensitive element does not exceed 15 kg (for comparison, the mass of magnetic current transformers of similar measurement ranges is an order of magnitude more).Based on the foregoing, it was decided to develop a measuring system based on the Faraday magneto-optical effect in optical fiber and use digital fiber-optic and electronic components to process the output signal of the measuring system.