Environmentally friendly insulating gases are increasingly being explored as substitutes for SF6 due to environmental concerns. CF3SO2F gas exhibits excellent insulation and environmental protection properties, making it an ideal substitute for SF6. In electrical equipment, the insulating gas is subjected to prolonged exposure to external electric fields. However, there has been no research conducted on the microscopic effects of electric fields on CF3SO2F gas. In this article, the electrical properties of a new environmentally friendly insulating medium CF3SO2F under external electric field are investigated from a microscopic perspective through density functional simulations. The impact of electric fields on geometric structures is analyzed based on the structural characteristics of gas molecules, while the effect of electric field polarization on the insulation performance of gas molecules is revealed through space charge characteristics. The results indicate that the molecular bond length undergoes significant changes under prolonged polarization of the electric field, leading to a gradual decrease in the energy gap of the front orbital and an improvement in molecular conductivity. Consequently, stability continuously declines until chemical bond fracture occurs when the energy gap reaches a certain threshold. This is consistent with the IR spectra and contributes to understanding the electric breakdown mechanism of insulating gases, providing a valuable reference for detecting gas breakdown through infrared spectroscopy.

Cellulosic insulation paper is usually used in oil-immersed transformer insulation systems. In this study, the molecular dynamics method based on reaction force field (ReaxFF) was used to simulate the pyrolysis process of a cellobiose molecular model. Through a series of ReaxFF- Molecular Dynamics (MD) simulations, the generation path of ethanol at the atomic level was studied. Because the molecular system has hydrogen bonding, force-bias Monte Carlo (fbMC) is mixed into ReaxFF to reduce the cost of calculation by reducing the sampled data. In order to ensure the reliability of the simulation, a model composed of 20 cellobioses and a model composed of 40 cellobioses were respectively established for repeated simulation in the range of 500–3000 K. The results show that insulating paper produced ethanol at extreme thermal fault, and the intermediate product of vinyl alcohol is the key to the aging process. It is also basically consistent with others’ previous experiment results. So it can provide an effective reference for the use of ethanol as an indicator to evaluate the aging condition of transformers.

In this study, the quantum chemical method was used to investigate the microscopic characteristics of α-poly viny difluoride (PVDF) molecules under the influence of an electric field, and the impact of mechanical stress and electric field polarization on the insulation performance of PVDF was analyzed through the material’s structural and space charge characteristics. The findings reveal that long-term polarization of an electric field leads to a gradual decline in stability and a reduction in the energy gap of the front orbital, resulting in the improved conductivity of PVDF molecules and a change in the reactive active site of the molecular chain. When the energy gap reaches a certain value, a chemical bond fracture occurs, with the C-H and C-F bonds at the ends of the backbone breaking first to form free radicals. This process is triggered by an electric field of 8.7414 × 10⁹ V/m, which leads to the emergence of a virtual frequency in the infrared spectrogram and the eventual breakdown of the insulation material. These results are of great significance in understanding the aging mechanism of electric branches in PVDF cable insulation and optimizing the modification of PVDF insulation materials.

The ethylene propylene diene monomer (EPDM) is utilized in high voltage direct current (HVDC) cable accessories due to its exceptional insulation properties. The microscopic reactions and space charge characteristics of EPDM under electric fields are studied using density functional theory. The results indicate that as the electric field intensity increases, the total energy decreases while the dipole moment and polarizability increase, leading to a decrease in the stability of EPDM. The molecular chain elongates under the stretching effect of the electric field and the stability of the geometric structure decreases, resulting in a decline in its mechanical and electrical properties. With increased electric field intensity, the energy gap of the front orbital decreases, and its conductivity improves. Additionally, the active site of the molecular chain reaction shifts, leading to different degrees of hole trap and electron trap energy level distribution in the area where the front track of the molecular chain is located, making EPDM more susceptible to trapping free electrons or injecting charge. When the electric field intensity reaches 0.0255 a.u., the EPDM molecular structure is destroyed, and its infrared spectrum undergoes significant changes. These findings provide a basis for future modification technology, and theoretical support for high voltage experiments.

Characterized by its exceptional electrical, physical, and chemical properties, 1-phenyl-1-xylylethane (PXE) insulating oil finds extensive application in the realm of power capacitor insulation. In this study, molecular simulation is employed to investigate the reactivity of PXE insulating oil molecules and the impact of temperature on water diffusion behavior in PXE insulating oil, as well as its solubility. The findings demonstrate a higher propensity for hydrogen atoms in nucleophilic and electrophilic positions within PXE insulating oil molecules to interact with water molecules. The inclusion of a temperature field enhances the Brownian motion of water molecules and improves their diffusion ability within the oil. Furthermore, the temperature field diminishes the interaction force between water molecules and the oil medium. Under the influence of this temperature field, there is an increase in the free volume fraction of PXE insulating oil, leading to a weakening effect on hydrogen bonds between oxygen and hydrogen atoms within PXE insulating oil. Additionally, with increasing temperature, there is an elevation in moisture solubility within insulating oil, resulting in a transition from a suspended state to a dissolved state.