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.

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.

Polyurethane (PU) materials are extensively utilized in power equipment. This paper introduces a comprehensive evaluation method that combines electromagnetics and computational chemistry based on the Density Functional Theory (DFT) to elucidate the impact of external electric fields on the molecular structure of PU during electrical contact. The study focuses on the microstructural and molecular energy changes in the hard (HS) and soft (SS) segments of PU under the influence of an electric field of uniform intensity. Findings indicate that the total energy of HS molecules decreases markedly as the electric field intensity increases, accompanied by a significant rise in both the dipole moment and polarizability. Conversely, the total energy and polarizability of the SS molecules decrease, while the dipole moment experiences a slight increase. Under the influence of a strong electric field, HS molecules tend to stretch towards the extremities of the main chain, leading to structural instability and the cleavage of hydroxyl O-H bonds. Meanwhile, the carbon chain of the SS molecules twists towards the center under the electric field, with no chemical bond rupture observed. At an electric field intensity of 8.227 V/nm, the HOMO-LUMO gap of the HS molecule narrows sharply, signifying a rapid decline in the molecular structure stability, corroborated by infrared spectroscopy analysis. These findings offer theoretical insights and guidance for the modification of PU materials in power equipment applications.

Due to its high flash point, low viscosity, high solubility, low poor point, strong coloration ability, and high voltage resistance, 1‐phenyl‐1‐xylylethane (PXE) is widely utilized as an electrical insulation oil. In this study, density functional theory is employed to apply an electric field within the molecule for calculating the molecular structure and spatial charge characteristics of PXE under external electric fields. The alterations in molecular structure, reaction activity, and insulation properties of PXE when subjected to external electric fields are analyzed correspondingly. As the external electric field gradually increases, the potential energy of the molecule elevates leading to a decrease in stability of the molecular chain. Under conditions of high electric field intensity, the molecule experiences enhanced polarity and polarization, leading to alterations in the chemical bonds within the benzene ring and ultimately resulting in structural degradation. The space charge characteristics further demonstrate a gradual decrease in the energy gap of PXE molecule, accompanied by an enhancement in molecular conductivity under the influence of an external electric field. Meanwhile, the HOMO and LUMO orbitals exhibit a gradual localization towards the two termini of the molecular chain, and the active sites of PXE molecular chain underwent alterations, resulting in both ends of the chain exhibiting electrophilic and nucleophilic reactivity. The variation in trap energy levels at different depths results in the distortion of local field strength within the PXE. The absorption peak in the high frequency region of the molecular infrared spectrum exhibits a noticeable redshift, while the absorption peak in the low frequency region experiences a blue shift. The research findings can establish a theoretical framework for the micromorphology analysis of electric aging insulation oil in power capacitors, thereby offering a reference point for determining the breakdown voltage value in macroscopic electrical breakdown experiments. Additionally, these results provide valuable insights into material optimization and modification strategies.