Abstract: Thermogravimetric analysis (TGA) and thermogravimetric infrared (TG-IR) techniques were used to investigate the pyrolysis characteristics of transformer oil KI25X at three different heating rates. It was found that the pyrolysis process mainly took place at 200~300 ℃ and 550~800 ℃, and the results show that the energy released by the thermal failure of the transformer will cause the pyrolysis degradation of the transformer oil, destroy the chemical bonds of the transformer oil, and produce low molecular hydrocarbon gas dissolved in it. The kinetic parameters of the pyrolysis process of transformer oil in N2 atmosphere were further calculated by using the thermodynamic theory of differential method and integral method. The comprehensive analysis of the pyrolysis characteristics of transformer oil provide a theoretical basis for the further study of thermal fault detection of transformer oil.

Key words: transformer oil, thermogravimetric infrared analysis, heating rates, pyrolysis kinetics