Comparison on the Pyrolysis Characteristics of PDMS, PIB, and NTO Based on ReaxFF

Naphthene transformer oil (NTO), poly-dimethyl-siloxane (PDMS), and polyisobutylene (PIB) are the most regularly used insulating oils in the power industry, but the comparative investigation on their degradation mechanism has not been carried out yet. Based on ReaxFF simulation, this work presents a microscopic examination of the cracking mechanisms of NTO, PDMS, and PIB. In setting up the study system, the elements influencing the cracking of insulating oil, such as time length, temperature, and moisture content, were set up as a single variable to be studied and assessed on a case-by-case basis. In addition, a macroscale comparison study is done in conjunction with a thermal aging experiment, and the simulation data are in good agreement with the experimental data. The creation of the characteristic gas accelerates as temperature rises, intensifying the breaking of all three insulating oils. Furthermore, it is discovered that temperature fluctuation has the biggest influence on the amount of the gas content in PIB. Based on the results, it is possible to further investigate the fault diagnosis criteria in order to ensure the safety of electrical equipment.