Research Of DC Current Measurement Technology Based On Optical Fiber Thermometry

HVDC has more advantages than HVAC, so it has become the focus of the development. With the development of HVDC, the technology of DC current measurement also becomes more and more important. With the increasing of voltage network level and the expansion of power system capacity, the traditional transformer shows more and more shortcomings, which can not meet the development needs of modern power supply. Although it has broad prospects, new type of optical fiber current sensor has many problems. The inherent birefringence problem of optical fiber in the all fiber current sensor is difficult to deal with. There will be the isolation problem because active fiber current sensors need the power supply part in the high voltage side.In this paper, the project of DC current measurement technology based on the thin film sensors is proposed, which combine the thin film sensing technology and the temperature measurement technology. So it has many advantages such as high insulating property, anti-interference, reliability and low cost and so on.In this paper principles and designs of electric-heating converter, heating-light converter and design of low-voltage measurement display system are introduced in detail. Then the experimental platform of this system is set to experiment. Two new proposes of thin file resistor are designed through the research of the existing thin film sensor, and one of them is determined by the analyses of the simulation and actual performance tests. Through the experiments, its feasibility is verified. Then, the relationship between the current and the time constant of fluorescent lifetimeτis input into the computer throw the calibration experiment of them. Finally, comparing the value of the time constant with the data comparison sheet, the current throw the thin film resistor can be Real-Time Detected and displayed.