Synthetic ester insulating oil is a promising alternative to mineral oil due to its superior environ-mental compatibility and electrical properties. However, its ester-based structure is susceptible to oxidation, compromising long-term stability. Antioxidant addition is an effective strategy to enhance oxidative resistance, yet conventional screening methods, relying on macroscopic valida-tion, fail to elucidate antioxidative mechanisms and are costly and inefficient. This study employs molecular simulations to analyze synthetic ester insulating oil with pentaerythritol ester as its primary component, quantifying the antioxidative performance of BHT and Tocopherol through bond dissociation energy (BDE), mean square displacement (MSD), free volume fraction (FFV), and binding energy (BE). The results indicate that Tocopherol, with lower BDE, stronger an-ti-migration ability, smaller FFV, and higher BE, demonstrates superior antioxidative activity by effectively neutralizing free radicals, inhibiting oxygen diffusion, and enhancing solubility sta-bility. These findings provide a theoretical basis for the selection, optimization, and molecular design of antioxidants in synthetic ester insulating oils, supporting the development of high-performance insulating oils.

Synthetic ester insulating oil,molecular simulation,antioxidants,oxidative stability