HIGH-LIMIT DETECTION AND ACCURATE ANALYSIS OF ACETYLENE IN TRANSFORMER OIL GASES WITH A TUNABLE LASER-BASED PHOTOACOUSTIC SPECTROMETER
Z. Wu1,2, L. Zhai1, X. He2, Q. Yu1
1School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116023 China
2Information Engineering Department, Environmental Management College of China, Qinhuangdao, 066004 China
Keywords: photoacoustic spectroscopy, acetylene, second harmonic, transformer oil discharge, tunable laser
Abstract
Acetylene in transformer oil is an important feature gas, which can reflect early discharge faults. A tunable fiber laser photoacoustic (PA) spectrometer based on second harmonic modulation, with its fast response and good noise immunity, can be well applied to detect trace gases. In this work, the second harmonic PA measurement of the acetylene gas at the 1530.3709 nm transition line is demonstrated. An accurate analysis of acetylene in transformer oil gases is ensured by using an overcomplete-independent-component-analysis(ICA)-basis BSS model and a five-point-sampling method to improve the detection limit from 1.12 to 0.71 ppb. The experiment for detecting and analyzing acetylene in transformer oil gases shows that the discharge acetylene productivity can reach 303.72 ppb/s with a dynamic response time of less than 10 s, relative error of about 1.40%, and relevance coefficient up to 0.99946. At room temperature and atmospheric pressure, this can meet the demands of acetylene detection and analysis in early or ultra-early predictions of transformer discharge faults.
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