The Study Of Cable’s Temperature Monitoring System Based On Fiber Grating

In the electric power system operation of our country, the safe operation of the cable is the security of the entire power supply network. The cable is working in the environment of high temperature, high radiation, high voltage for a long period, after a long time, overheating or short circuit can cause a fire. Therefore, it is necessary to real-time monitor the temperature of the cables. Monitoring in the accident early can find the problems and take appropriate measures, the fire can be prevented effectively. The cable temperature monitoring can not just local measurements, it must achieve the monitoring of the whole line. In recently years, the development of fiber grating sensing technology is deeply concerned, FBG sensors have the advantages of high sensitivity, strong anti-electromagnetic interference capability, good insulation, small size, wide dynamic range and so on. It is suit to monitor in the complex and harsh environments, it can achieve the real-time temperature monitoring of the cable.First of all, understand the fiber grating sensor technology development and development trend at home and abroad, analysis the measurement principle of fiber grating and several fiber grating wavelength demodulation methods. The overall program of cable temperature monitoring system was proposed based on the technology of fiber grating temperature measurement. Using ANSYS finite element analysis software to build the cable model,simulation and analysis the temperature distribution of fiber grating, according to the simulation results, we can determine a reasonable position to put fiber grating and provide a basis for the experiment. Then, it is the design of the temperature measurement system, the cables temperature monitoring system based on fiber grating composed of a broadband light source, fiber grating, optical circulator, wavelength demodulation module and temperature monitoring program based on the LabVIEW programming language, When the temperature around the cables changes, the central wavelength of the fiber grating will also changes.Broadband light transmits by the optical circulator to the fiber grating, reflection condition to meet the light by the optical fiber into the wavelength demodulation module, photoelectric signal conversion is complete, wavelength demodulation module transmit the value of the center wavelength of the reflected light and the corresponding optical power information to the computer. The computer obtain the information from the demodulation module by theLabVIEW program, the acquired data is displayed in the form of XY coordinate graph, Finally,the system experiment data results are verified the feasibility of the system.