基于光学互易回路的全光纤电流互感器的研究与应用

Research and application of all-fiber optic current transformer based on optical reciprocity loop

针对传统有源电磁式互感器易饱和、稳定性与抗干扰能力差、安装受限等问题,本文基于Faraday磁光效应,设计了一种无源全光纤电流互感器,通过旋光角来测量被测电流;设计互感器以HB Spun光纤作为传感元件,无饱和现象,可用于大电流测量;利用光学互易回路,消除光路中温度、光纤缺陷等因素对旋光角测量的干扰;采用反射式光路将电场引起的旋光角放大4倍,实现小电流的精确测量;传感元件采用柔性传感光纤环结构,形状可变,适应复杂空间内电流的测量。对比了不同圈数的柔性光纤传感环与标准电流互感器的测量精度,结果表明,本文设计的光学互易回路可以消除温度对电流测量的影响,全光纤电流互感器在-5℃~70℃全温度范围内精度为0.5,可实现小电流的精确测量。

Aiming to the problems of traditional active electromagnetic transformer such as easy magnetic saturation,poor stability and anti-interference ability,and limited installation,etc.,this paper designs the optical fiber current transformer to measure current by rotation angle based on Faraday magneto-optic effect;HB Spun optical fiber is used as sensing element without saturation and can be used for high current measurement.The designed transformer uses the optical reciprocity loop to eliminate the interference of temperature and optical fiber defect on the measurement of optical rotation angle,and uses reflector to enlarge the optical rotation angle to four times,which can realize accurate measurement of small current;Sensing element uses flexible fiber ring with shape variability characteristic,which helps for measurement of current in complex space.The paper compares flexible fiber ring with different loops to standard current transformer,the results show that optical reciprocity loop can eliminate the interference of temperature on the current measurement and the accuracy of all-fiber current transformer is 0.5 in the range of-5℃~70℃,which can realize the accurate measurement of small current.