基于正弦波调制的光纤电流互感器传感环误差分析

Error Analysis of Fiber Optical Current Transformer's Sensing Ring Based on Sinusoidal Modulation

传感环由λ/4波片、传感光纤和反射镜组成,它是光纤电流互感器(fiber optical current transformer,FOCT)中最重要的传感部分,因此也是FOCT最主要的误差源之一。针对正弦波调制系统中的传感环做误差分析,引入比例因子来衡量误差对系统的影响。指出:λ/4波片的45°熔接误差和相位误差对比例因子的影响是余弦关系。对传感光纤引入的误差分析显示:传感光纤的圆双折射越大、线性双折射越小,对比例因子的影响越小。相关实验也与理论分析基本吻合。

The sensing ring is composed of quarter wave plate, optical fiber sensor and mirror, and it is the most important sensing part of fiber optical current transformer(FOCT), therefore, it is one of the main error source of FOCT. This article analyzed the error of sensing ring which is in sinusoidal modulation system. A scale factor(SF) was mentioned to measure the effect on system error. To quarter wave plate, the affect by 45° fusion error and phase error on the scale factor is cosine relationship. To sensing fiber, the circular birefringence is greater, linear birefringence is small, thus influence on the scale factor is smaller. The experiment can prove the correctness of the theory.