Study On Fiber Bragg Grating Current Sensor System

With the development of electric power industry, the traditional current sensor can't meet the requirement of recent industry technology. Nowadays, the fiber current sensor will become a most preponderant substitute of traditional current sensor. Compared with traditional current sensor, fiber current sensor have the superior characteristics of excellent insulating capability which ensured the signal unaffected by surrounding magnetic field , no power needed, small volume and high sensitivity. So, the fiber current sensor researching becomes a hot direction in the research field.Fiber bragg grating is one of the fiber passive devices which developed rapidly recently. It is made directly on the fiber core and has the features of small volume and determinate center wavelength. The reflected wavelength of Fiber bragg grating can be modulated by temperature and strain, so it applied widely in the fiber sensor field.In this experiment, the current was measured by combination fiber bragg grating with super magnetostrictive material (Tb-Dy-Fe). Firstly, we simulated strong AC current, and obtained the current that meets the requirement of the sensor after a series of transformation, secondly, the Tb-Dy-Fe contracted by the magnetostrictive effectiveness under magnetic field which cause optical fiber gained an axial strain, and then, bragg wavelength excursion was produced. Bragg wavelength excursion can be measured, so the current derived from magnetic field can be obtained. The main contents are as following:1. Combination fiber bragg grating with magnetostrictive materials, the scheme of sensor system which meet the requirement of strong AC current detection was designed.2. Simulated AC strong current in the lab, and got the current on equivalent industry spot.3. Design sampling, AC—DC transform, amplification circuit, energy supply circuit of of high voltage side, and obtained the current which can drive the magnetostrictive materials to produce the fiber bragg grating axial strain.4. According to the actual magnetostrictive materials and the fiber bragg grating, finished the system designation and optimization, including the core material, the main coil, magnetism loop, heat insulation layer.5. Finish the measuring and the analyzing of current data of the fiber bragg grating current sensor. The sensitivity of the sensor is 3.47 X 104nm / mA.Eventually, sum up the work, and put forward improved measurements for overcome the shortage of the experiment.