Study on the gas pressure characteristics of photoacoustic spectroscopy detection for dissolved gases in transformer oil

Photoacoustic spectroscopy (PAS) is a highly sensitive gas analyzing method without the shortcoming of gas consumption, which can be well applied in online monitoring of dissolved gas-in-oil. The effect of gas pressure on the photoacoustic spectroscopy detection is significant. Functional relations between gas pressure and gas absorption coefficient as well as PAV signal were derived theoretically. The experimental results of the acetylene , methane and carbon dioxide dissolved in transformer oil show the correctness of the functional relations above and that Photoacoustic spectroscopy voltage signal has a good linear dependence on the 1.5th root of P (0KPa<;P<;75KPa ) and the square root of P(75KPa<;P<;100KPa)when without gas absorption saturation effect. The theoretical and experimental results supply reference and technical support for further improvements in oil gas photoacoustic spectroscopy of on-line monitoring system.