Research on Laser Cavity Ring-down Spectroscopy and Fiber-Based Measurement for SF6 Decomposed Gases

Abstract

The four species gases including H2S, CO, HF and SO2 in the decomposition gas of SF6 were monitored online, according to the power industry requirements. The calibration technology and the algorithm, the optical path of cavity and signal to noise ratio of detection circuit are the key steps in the development of decomposed gas monitoring device. This paper first introduces the calibration method and technology of multi-component trace gas analysis instrument based on photo-acoustic spectroscopy. An on-line monitoring device for SF6 decomposition gas based on the laser absorption spectroscopy is developed. The calibration algorithm is proposed and verified by experiment. Within the range of 0~200ppm, the stability is less than 2%. The concentration calibration method proposed in this paper can effectively monitor the concentration of H2S, CO, HF, SO2 typical characteristic gases, and provide theoretical and technical guidance for SF6 gas insulated high-voltage combined electrical apparatus.