Error characteristic analysis and experimental research on a fiber optic current transformer.

Abstract

To solve the operation precision problem of a fiber optic current transformer (FOCT), we have established models of the polarization error based on the Jones matrix and a model of the temperature drift error taking into account the bending characteristics. The polarization study shows that a greater extinction ratio of the polarizer and analyzer and a smaller deviation of the polarization direction lead to a smaller output error. Temperature analysis suggests that greater intrinsic linear birefringence, a smaller bending radius, and more winding turns of the sensing fiber should exacerbate temperature drift and reduce the temperature range to meet an accuracy of class 0.2. Furthermore, we have constructed an experimental platform and performed current tests for different extinction ratios, polarization direction deviations, and temperature conditions. The experimental results confirm the effectiveness of the theoretical analysis.