Abstract
The size of optical fi ber current sensors with a Faraday effect can be small with greater weight savings compared with electromagnetic induction type CTs. We advanced such utilizations for power equipment, especially for optical fi ber current sensors that use fl int glass fi ber for the Faraday element. This paper outlines the principle, the composition of optical CTs, and fault point location systems to which an optical fi ber current sensor is applied as well as the practical use situations and the development status of 500-kV independence type optical CTs that are aimed at applications in all digital substations.
