Influence Mechanism of Metal Passivator BTA on the Methanol Formation From Insulating Paper Based on ReaxFF-MD

Methanol has been proposed as a chemical indicator for assessing the aging condition of insulating paper in oil-immersed transformers. The metal passivator benzotriazole (BTA) is widely added to insulating oil as a method to inhibit oil-sulfur corrosion. Existing researches rarely pay attention to the influence of by-products generated by BTA degradation on the methanol indicator. In this article, the effect of BTA additives on the generation of methanol from the aging of insulating paper was investigated based on molecular dynamics simulation. Simulation results showed that the addition of BTA could promote the production of methanol from cellobiose. Then, three reaction pathways of methanol production promoted by BTA were summarized based on the simulation results. Finally, the effect of different BTA concentrations on the methanol content in the oil was analyzed by accelerated thermal aging experiments. The experimental results showed that the methanol concentration in oil was the highest at 100-mg/kg BTA concentration and the lowest at 0-mg/kg BTA concentration. The correctness of the molecular dynamics simulation results was confirmed. This work aims to explain the microscopic effect mechanism of metal passivator BTA on methanol generation during insulating paper aging from the perspective of molecular dynamics simulation.