Photoacoustic spectroscopy can effectively detect dissolved methane in transformer oil. The enhancement of weak PA signals can be achieved by using a resonant photoacoustic cell. However, due to the large volume of the buffer chamber of the traditional resonant photoacoustic cell, it is difficult to detect the dissolved gas in transformer oil with limited gas volume. In this paper, a resonant photoacoustic cell with optimized volume was fabricated. The fabricated photoacoustic cell was used to detect the characteristic methane dissolved in transformer oil. The stable detection limit of CH4 gas was obtained as 52 ppb. Using the optimized volume of the photoacoustic cell can greatly reduce the gas volume on the premise of ensuring measurement sensitivity.

photoacoustic spectroscopy;photoacoustic cell;dissolved gas analysis in oil;transformer