Insensitivity of Fiber-Optic Current Transducer to Vibration

The traditional fiber optical current transformer uses Y-branch waveguide modulator. However, Y-branch waveguide modulator produces abnormal noise current when it is subjected to vibration stress caused by the double-arm optical structure between the modulator and the coupler. In this paper, a new optical structure using reflective waveguide modulator is proposed because it has ability to eliminate the additional phase difference caused by vibration stress. Both results of laboratory and substation prove that reflective waveguide modulator can not only effectively reduce the impact of environmental stress on fiber optical current transformer, but also can eliminate the abnormal current caused by circuit breaker switching vibration. This study provides a new way of thinking and direction for the design and manufacture of high performance current transformer applying to high voltage and large current measurement field.