Dissolved gas analysis (DGA) of transformers provides valuable in-sights into the electrical thermal and pressures encountered by power transformers. It helps spot initial indications of transformer faults, thereby assisting in preventative damage prevention. It is a reliable and sensitive method for detecting developing fault conditions in power transformers. The study seeks to examine both fresh and artificially aged synthetic ester oil. This study examined the impact of an emerging thermal fault on Cerium (IV) oxide (CeO2) based nanofluids using a DGA Analyzer. Nanofluids were formulated with four different concentrations: 0.004 (wt.%), 0.008 (wt.%), 0.012 (wt.%) and 0.016 (wt.%) and the dissolved gas concentrations in the nanofluids were analysed. In this experimental work to investigate the dissolve gas analysis of accelerated aged nanofluids using CeO2 nanoparticles Due to the thermal fault, fault gases were released and dissolved into the oil. The highest TDCG level was found in the CeO2 nanofluid sample with a concentration of 0.012 (wt.%), sample (S3), followed by the 0.016 (wt.%) sample (S4), and then samples (S2) and (S1). The concentrations of H2 and C2H4 were notably higher in the nanofluid samples, with C2H4 levels being significantly elevated in samples S1 and S4 when exposed to the thermal fault.