Photoelectric Hybrid Current Sensor Combination of LPCT and FFI

A new kind of photoelectric hybrid current sensor is designed. The low-power current transformer (LPCT) is used as the primary sensor for current conversion. The optical fiber Fizeau interferometer acts as the secondary sensor for noncontact microvibration detection. An electro-dynamic structure works as a bridge connecting the two sensors. Using two different ways as frequency response analysis and linear fitting method, similar sensitivity results are obtained. It is considered to be 3.5152 nm/A when the current frequency is 50 Hz. When LPCT works at the rated primary current of 450 A, the maximum measurement ratio error and phase displacement are <0.25% and 0.066 rad, respectively.