Using Fiber Bragg Grating sensor on ice monitoring on electric power transmission lines, part I: the measurement of the temperature

A temperature measurement system and algorithm method based on Fiber Bragg Grating (FBG) sensors and Fabry-Perot Filter (FPF) is put forward. Three reference FBGs were used to eliminate the change of the FPF induced by the environment temperature and the nonlinearity of the FPF. Two FBG temperature sensors with different temperature sensitivity were used to measure the temperature, without the expensive standard light wave length component that provide absolute stable light wave length. Arithmetic was induced how to using the fixed wavelength difference of the reference FBGs to eliminate the influence of the environment temperature, and how to using the difference sensitivity of the temperature FBGs to get the absolute temperature of the transmission lines. Experiments with a glass of water were made to contrast the measurement results of this system with that of a mercury temperature meter whose precision is 0.1°C. The experiment results shown that this FBG system has precision bigger than 99.5%.