Research on Optical Fiber SF₆Density Monitoring Technology

In china, all aspects of people’s production and life is closely related to the electric power industry security。 At the same time, with the development of science and technology and the needs of the development of the intelligent power grid, and this results in a more serious requirement on the precision and the intelligent for the SF6density monitoring equipment used in substation. Optical fiber grating sensor is an advanced subject in the detection fields.Optical fiber Bragg grating sensor being used density monitoring equipment is superior than traditional monitoring equipment in the sensitivity, resistance to electromagnetic interference, response time, and networkingIn this paper research the pressure sensor and temperature sensor based on the theory of optical fiber grating, with the density of the gas for SF6monitoring as goal. By analyzing fiber grating wavelength coupling theory, that gives the pressure and temperature sensor theoretical foundation, establishes the optical fiber grating pressure, temperature sensing the mathematical model, and puts forward a through the optical fiber type SF6density of the gas monitoring system.In the same environment, this experiment system using pressure and temperature sensor get the temperature of information and information pressure temperature information respectively, and compensate for the temperature information contained in pressure value information, the goal of these is reducing the system error detection. According to the characteristics of the system, we design the corresponding signal demodulating circuit. With FPGA Cyclone II EP2C8Q208C8microprocessor as control core, we completed the photoelectric signal conversion, analog-to-digital conversion, amplification and filter and light signal modulation circuit design. This part completed modulation and demodulation function of optical signals, through the Ethernet transmit the demodulated information to the computer, the calculation of density, data display and data analysis and storage is completed by LABVIEW. Density of the gas monitoring system in is studied, and verifies the feasibility of monitoring solution, and the output signal waveform and numerical analysisprocessing. Finally, it is proved by experiments on each part in the system that the feasibilityof the new method, at the same time we do analysis for output signal. Data index can meet theengineering need.