An optical fiber magnetic field sensor based on Faraday effect for transformer leakage magnetic field measurement

Transformers occupy a pivotal position in the power system. Accurately obtaining the distribution and variation of leakage magnetic field inside transformer is of great significance for transformer design and short-circuit deformation fault diagnosis. This paper proposes a small-size optical fiber magnetic field sensor based on the Faraday effect, of which the sensing characteristics and measurement accuracy are calculated theoretically and tested experimentally. The results show that the sensor can accurately measure the magnetic field and meet the requirements of magnetic leakage measurement in the transformer. The size of the sensor is optimized to be flexibly installed inside the transformer windings to achieve accurate measurement of internal leakage magnetic field under normal operation and short circuit conditions.