全光纤电流互感器系统光纤器件的双折射误差分析

Birefringence error analysis of optical fiber devices in all fiber current transformer system

为给反射式全光纤电流互感器(光CT)出现测量偏差问题提供理论依据,研究反射式光CT系统的主要光学器件对系统响应的影响机理,分析光CT各主要光学器件非理想性对电流测量准确性的影响。首先,采用琼斯矩阵描述了该系统各主要器件和数学模型,并给出系统输出光的表达式和解调检测后系统的注入电流测量值;然后,基于系统数学模型,分别分析了传感光纤的线性双折射、圆双折射的偏差和保偏光纤的线性双折射对光CT的注入电流测量值的影响。研究结果表明:传感光纤的线性双折射偏差对光CT注入电流测量准确度的影响最为突出;传感光纤的圆双折射的存在可以有效地抑制传感光纤线性双折射对光CT注入电流测量准确度的影响。

In order to provide a theoretical basis for the measurement deviation of reflective all fiber current transformer(optical CT),the influence mechanism of the main optical components of reflective optical CT system on the system response is studied,and the influence of the non ideality of the main optical components of optical CT on the accuracy of current measurement is analyzed.Firstly,the main devices and mathematical models of the system are described by Jones matrix,and the expression of the output light of the system and the measured value of the injection current of the system after demodulation and detection are given.Then,based on the system mathematical model,the effects of the linear birefringence and circular birefringence of the sensing fiber and the linear birefringence of the polarization maintaining fiber on the injection current measurement of optical CT are analyzed respectively.The results show that the linear birefringence deviation of sensing fiber has the most prominent influence on the measurement accuracy of optical CT injection current.The circular birefringence of sensing fiber can effectively suppress the influence of linear birefringence of sensing fiber on the measurement accuracy of optical CT injection current.