Integrated Oil-Gas Separation and Raman Spectroscopy Gas Detection Component for Online Dissolved Gas Analysis in Transformer Oil

Online dissolved gas analysis (DGA) is an effective method for diagnosing incipient insulation faults of oil-immersed power transformers. This paper proposes an integrated oildissolved gas detection component based on Teflon AF2400/PTFE hollow fiber composite membrane and fiber-enhanced Raman spectroscopy gas detection. A study on the Raman spectroscopy detection of dissolved hydrocarbon components is conducted. With an incident laser power of 200 mW, the limits of detection at 1 bar and with 60 s integration time for CH<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf>, C<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf>, C<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf>, and C<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> are 1.02, 3.32, 1.60, and 2.18 ppm, respectively. Under oil flow velocity of 5 mL/min, 4 hydrocarbon components can reach oil-gas equilibrium within approximately <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3-4 ~\mathrm{h}$</tex>. Equilibrium time is decreased but a marginal effect is observed when increasing oil flow velocity to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{1 5 ~ m L} / \mathbf{m i n}$</tex>. This paper establishes the foundation for the combined application of membrane-based oil-gas separation and Raman spectroscopy in online DGA.