CRDS-based measurement of CO/CO2 concentration ratios for assessing transformer insulation aging

A gas analyzer has been developed using cavity ring-down spectroscopy (CRDS) technology, designed to simultaneously measure the concentrations of CO₂ and CO. These gases are critical indicators of transformer insulation degradation. The analyzer covers a CO₂ concentration range from a few ppm to several thousand ppm and can measure CO/CO₂ concentration ratios from 0.076 to 0.8. The selected absorption lines for CO and CO₂ are centered at 6337.99 and 6338.59 cm⁻¹, respectively. The two candidate lines are proximate to each other and nonoverlapping. The experimental results indicate that the system accurately fits the measured and calculated signals, enabling concentration measurements at the ppm level. This confirms its ability to measure the gas concentrations and ratios critical for assessing the condition of transformer insulation. This CRDS-based system offers a reliable and sensitive method for early detection of potential transformer faults.