将超磁致伸缩材料(GMM)棒粘贴光纤布拉格光栅(FBG)的体系置于电流感应磁场中,构成光学电流互感器,用导磁材料构建磁路系统以约束并引导磁力线进入GMM。用永磁体材料建立偏置磁场以确定系统静态工作点,应用有限元分析磁路的磁场分布并设计了磁路的结构尺寸。利用粗波分复用器(CWDM)线性边带对光纤光栅交变应变解调,实现对交流电流信号的检测。实验测得偏置磁场为30 kA/m时,该系统在线性区最大可测电流为186 A,可获得4.3%的满量程精度。利用快速傅里叶变换(FFT),分析工频电流互感器不同输出信号的谐波分量,对输出信号进行质量评价。表明在线性区,互感器的输出信号基本不受GMM回滞特性和非线性特性的影响。

An optical current transformer is constructed by exposing gain mangetostrictive material (GMM)-FBG system to current-induced magnetic field. Ferro-magnetic materials are used to design a loop to constraint and conduct the flux into GMM. The permanent magnetic material is used in loop to establish a bias flux to form a working bias for the system. Finite element method is used to analyze and design the loop structure and the size. Coarse wavelength division multiplexing (CWDM) device is used to demodulate the alternating strain on FBG caused wavelength drift to realize sensing of the current. In the experiment,the maximum current is 186 A and the full scale accuracy is 4.3% when the system workes in linear region by setting the bias in 30 kA/m. Fast Fourier transform algorithm (FFT) is used to analyze the harmonic component of the output signal to evaluate the quality. It is demonstrated that the output signal is not influenced by hysteresis and nonlinear effect of GMM in linear region.