The Investigation of FBG sensor system for the transmission line icing measurement

It causes a lot of accidents and influences power system security in our country by the transmission line icing, the research and prevention of line icing are in process all the time. At present, the majority of electrical Company adopt electrical signal sensor to measure temperature, but some localization lies in them more or less; the scan time lasts quite a long time in traditional fiber temperature measuring system. However, fiber Bragg grating is an insulator and is small, and it has the advantages of low-price, simple structure, safety, no electromagnetic interference, so are particularly suit for measuring temperature, strain and stress. This paper uses fiber Bragg grating as the sensor of on-line monitoring system of electrical equipment. A novel fiber Bragg grating sensor interrogation system based on a tunable fiber Fabry-Perot(FFP) filter was demonstrated. A reference fiber Bragg grating (FBG) was used as a wavelength reference element. By measuring the wavelength difference between reference FBG and sensor FBG, the drift of tunable FFP filter´s cavity length was compensated. A quadratic fit function was made with software based on experiment results. This function showed a good fit to the relationship between the displacement of PZT and control voltage. It was used to calculate the wavelength of the sensing FBG Experiment results show that the measured error caused by the drift of FFP filter´s cavity length and PZT´s nonlinearity is greatly reduced and a higher accuracy is obtained.