Research Progress of All-Fiber Optic Current Transformers in Novel Power Systems: A Review

The new electric power system, dominated by renewable energy sources, demands current transformers with wide bandwidth and broad dynamic sensing capabilities. An all-fiber optic that combines fiber optic sensing technology with the Faraday magneto-optical effect offers an effective solution for precise dynamic current sensing. The paper first introduces the principle and basic optical path structure of the all-fiber optic current transformer (AFOCT), followed by a discussion on the error factors affecting the measurement performance and operational reliability of AFOCT. It then summarizes and presents specific solutions developed over the past decade. Lastly, the paper concludes with a summary and future outlook on applying AFOCT in power grids. Optical current transformers are currently widely used in ultrahigh and extra-high voltage transmission engineering. As optical current transformer technology matures, coupled with advancements in intelligence levels, the prospects in the field of current measurement are broad and promising.