Infrared absorption properties analysis of dissolved gases in transformer oil

Infrared absorption properties of fault gases are the theoretical bases of qualitative and quantitative analysis of dissolved gases in transformer oil by infrared optical methods. This paper proposed a method that can calculate gaseous infrared absorption spectrum at a given pressure or temperature. Using spectroscopic parameters found in the HITRAN2004 database, the infrared absorption properties of CH₄, C₂H₆, C₂H₄, C₂H₂, CO, CO₂ and H₂O were researched by the method. The infrared spectra of these gases in the spectral region of 500~4000 cm^-1 were given. And the laws that the peak absorption coefficient and full width at half maximum value (FWHM) of an absorption line vary with pressure and temperature were also analyzed. Calculation and analysis results are particularly useful for the online and offline detection of dissolved gases in transformer oil by infrared optical methods such as Fourier transform infrared spectrometry and photoacoustic spectrometry.