Quartz‐Enhanced Photoacoustic Spectroscopy Sensor for Detection of Dissolved Carbon Monoxide in Transformer Oil

ABSTRACT In this paper, we proposed a quartz‐enhanced photoacoustic spectroscopy (QEPAS) sensor system for detecting dissolved carbon monoxide (CO) in transformer oil. The sensor system was designed to be highly sensitive, compact, and cost‐effective. An on‐beam configured acoustic micro‐resonator (AmR) coupled with a quartz tuning fork functions as an acoustic transducer to enhance photoacoustic signals. This sensor system achieved a minimum detection limit (MDL) of 0.37 ppm for CO based on the absorption line with a wavelength of 2333.72 nm. This value is three orders of magnitude lower than the safety threshold specified in relevant standards for dissolved gas detection in transformer oil. The proposed method offered high sensitivity, low cost, a compact form factor, and ease of integration, offering a novel technical solution for dissolved gas detection in transformer oil.