To address the degradation of insulation and mechanical properties and the risk of lightning strikes caused by insulator icing, this study developed an environmental friendly and recyclable superhydrophobic material (DGEAC/SiO₂-POTS). Silica was obtained through sol-gel hydrolysis, and SiO₂ particles were modified with n-octyltriethoxysilane (POTS). This SiO₂ particles were then mixed with multifunctional polyester (DGEAC), and micro/micro/nano three-layer hierarchical superhydrophobic coating was constructed on the surface of the insulator through phase separation technology. The results show that the coating exhibit exceptional superhydrophobicity with a contact angle of 162.2° and a rolling angle less than 5°; the coating maintains superhydrophobicity after 400 cycles of sandpaper abrasion, 100 cycles of tape peeling, and acid/base solution corrosion; the coating retains its hydrophobic effect after 15 cycles of high-low temperature alternating tests. Compared with bare insulators, the coating delays ice formation by 5.6 times at -20℃ and significantly reduces ice adhesion to 28.7 kPa. The innovative introduction of a dynamic covalent bond ester exchange mechanism enables the efficient recovery of SiO₂-POTS particles with stable performance using ethylene glycol. The material has a volume resistivity greater than 2.8×10¹⁴ Ω·cm and a peak breakdown voltage reaches 22.94 kV. This multifunctional material integrates anti-icing, durability, recyclability, and electrical safety, which can offer a promising green solution for protecting transmission equipment.

To address the resource dependence and recycling challenges faced by traditional petroleum-based epoxy resins in power equipment applications, this study synthesized a fumarate epoxy matrix (FPAE) from renewable rosin through Diels-Alder addition reaction. A curing agent (BDB) containing boronic ester dynamic bonds was used to construct a cross-linked network via thiol-epoxy click chemistry, and a rosin-based epoxy vitrimer material (FPAE-BDB) was prepared. The thermal, mechanical, and electrical properties, as well as degradation and recyclability characteristics of the material were systematically characterized by dynamic thermomechanical analysis (DMA), thermogravimetric analysis (TGA), tensile tests, dielectric spectroscopy tests, breakdown strength tests, and degradation/reprocessing experiments. The results show that the material exhibits excellent thermal properties. Its glass transition temperature (131.8℃) increased by 8.3% compared to the commercial DGEBA-MHHPA system (121.6℃). Its initial decomposition temperature (T_d5%=332.4℃) and 50% thermal weight loss temperature (T_d50%=408.6℃) are comparable with those of DGEBA-MHHPA system. Its characteristic breakdown strength reaches 44.38 kV/mm, which is 7.3% higher than the 41.35 kV/mm of DGEBA-MHHPA. Its dielectric constant remains stable at 3.5-3.8, and its dielectric loss factor is slightly higher than that of DGEBA-MHHPA. Additionally, the material demonstrates good chemical degradation and recyclability, which can efficiently degrade in acidic H₂O₂ solution at room temperature. After crushing, it is hot pressed at 160℃ and reshaped, its breakdown strength retention rate attains 92.5%. However, due to its rigid phenanthrene ring structure, the material exhibits high brittleness, leading to shortcomings in mechanical properties, and its tensile strength (38.9 MPa) is lower than that of the DGEBA-MHHPA system(72.1 MPa). In summary, compared to the DGEBA-MHHPA system, the FPAE-BDB system shows good thermal, electrical, and recovery properties. Future work may involve toughening modification to enhance its mechanical properties.

The C₄F₇N/CO₂/O₂ ternary gas mixture exhibits excellent environmental friendliness and insulation performance, but there is still a lack of research on the stability of C₄F₇N/CO₂/O₂ under trace moisture conditions during long-term operation of equipment. In this study, thermal decomposition experiments of C₄F₇N/CO₂/O₂ were conducted at different trace moisture concentrations. At the same time, reactive molecular dynamics simulations based on the ReaxFF force field were employed to explore the influence of moisture on the thermal decomposition characteristics of C₄F₇N/CO₂/O₂ from a microscopic perspective, and the correlation mechanisms between decomposition products and trace moisture was analyzed. The results show that the main thermal decomposition products of the gas mixture are CF₄, C₃F₈, C₃F₆, C₂F₆, and CHF₃. The increase of trace moisture concentration promotes the decomposition of C₄F₇N, leading to an increase in the concentration of decomposition products. However, when the trace moisture concentration further increases, the reaction pathways for generating the main decomposition products are inhibited. This inhibition leads to a downward trend in the concentrations of the main decomposition products, and promotes the formation of more secondary by-products and complex components, causing a shift in the decomposition pathways of the system.

Phase change cooling technology has high cooling efficiency and represents a novel approach to achieving efficient heat dissipation for high-power and large-capacity electrical equipment. This paper comprehensively investigated the feasibility of C₆F₁₂O as a phase change coolant. Combining the phase-field method based on the Cahn-Hilliard equation with the theory of electrohydrodynamic, considering the coupling effect of electric-flow-thermal-phase fields, numerical simulation research was conducted on the phase transition evolution process of C₆F₁₂O medium under varying temperature and electric field conditions, and then the bubble motion characteristics in the existing cooling medium C₆F₁₄ was compared. The results show that compared with C₆F₁₄, without an electric field, the change in temperature has a more significant impact on the bubble motion characteristics in C₆F₁₂O. The rise in temperature increases its bubble statistical velocity by 75.75%. An appropriate uniform electric field promotes the bubble evolution in the medium. Under the same superheat degree (∆T=0.056), the higher dielectric constant of C₆F₁₂O makes the polarization effect caused by the electric field more obvious, and it can transition to film boiling at a lower field strength. Under the action of horizontal uniform electric field, for different electric Bond numbers (B_oE), the statistical velocity of bubbles in C₆F₁₂O is generally lower than that in C₆F₁₄, while the bubble release period is shorter and the frequency is higher. Under the action of vertical uniform electric field, the bubble statistical velocity in C₆F₁₂O increases from 4.131 to 4.760, and the release period shortens from 3.889 s^-1 to 2.059 s^-1, and the bubble motion is more intense than that in C₆F₁₄.

In view of the strong greenhouse effect of SF₆ insulating gas, finding its alternative medium has become an industry consensus. Clean air, as an environmental friendly insulating medium, is considered as a promising candidate for DC GIS equipment. To investigate the insulation characteristics of high-pressure clean air, the breakdown characteristics of air at different pressures (0.6–0.9 MPa) under positive and negative lightning impulse voltages and DC voltage were measured in uniform and slightly non-uniform electric fields with a 10 mm gap. The time-volume theory was introduced, and a breakdown field strength prediction model was established based on this theory. Finally, the model predictions were compared with the experimental results. The results show that in uniform field, the breakdown field strength under negative polarity exhibits greater dispersion. In slightly non-uniform field, among the four cases, the breakdown field strength under negative lightning impulse is the lowest, and the breakdown field strength exhibits a saturation effect with the increase of pressure. The time-volume theory can accurately capture the trend of breakdown field strength changing with pressure. This model considers the electric field enhancement on the electrode surface caused by micro-protrusions, and the predicted results are in good agreement with the experimental results.

Due to its excellent anti-pollution flashover performance, silicone rubber is widely used in the external insulation of high-voltage power equipment. This anti-pollution performance of silicone rubber stems from its unique hydrophobicity transfer, which means that when the material surface is covered with contaminating particles, internal hydrophobic substances will transfer to the surface of the contaminated layer, endowing the contaminated layer with hydrophobicity. The quality of the hydrophobicity transfer of silicone rubber is directly related to its anti-pollution flashover performance. Understanding its hydrophobicity transfer mechanism and influencing factors can provide guidance for the development and use of silicone rubber. This paper summarized the hydrophobicity transfer mechanism of silicone rubber, as well as the influences of insoluble pollutants, soluble pollutants, temperature, humidity, formulation process, and electric field environment on the hydrophobicity transfer of silicone rubber, and put forward prospects for future research directions.

During the laying process, excessive lateral pressure and traction would cause mechanical damage to cables, leading to severe failures such as sheath grounding, overheating, insulation breakdown, and combustion during operation. This paper summarized the research progress on traction and lateral pressure of land cables, including their generation processes and effects on cable insulation structures and materials, calculation methods, monitoring, and online control techniques of traction and lateral pressure. The influence of mechanical stress on microscopic characteristics such as crystal size, crystallinity, and trap number and depth in cable insulation materials was discussed in detail, and the failure mechanisms of cable materials under mechanical stress were analyzed. Regarding the calculation methods for mechanical stress, the shortcomings of current approaches were summarized, and future research directions for cable mechanical stress were outlined.

High thermal conductive insulating materials are key functional materials for achieving efficient heat dissipation in motors, which is of great significance for improving the operational stability and prolonging the service life of motors. This article briefly described the thermal conductive modification mechanisms of insulating materials,reviewed recent research progress on high thermal conductive insulating varnish, mica tapes, films, and potting compounds used in motors, discussed their current application status in the field of motors, and further provided an outlook on future research direction.

To enhance the electrical insulation and mechanical properties of poly(m-phenylene isophthalamide) (meta-aramid, PMIA) nano paper-based materials, a modified alumina (A-Al₂O₃) with surface-grafted polar groups was prepared using air plasma treatment and introduced into PMIA paper as a reinforcing phase. The effects of different doping amount on the properties of the composite paper were systematically investigated. The results show that when the mass fraction of A-Al₂O₃ is 3%, the composite paper achieves optimal overall performance, with its breakdown strength increasing to 255.7 kV/mm, volume resistivity reaching 3.48×10¹⁵ Ω·m, and the dielectric constant improving while the dielectric loss remaining at a low level. This is attributed to the high insulation performance of A-Al₂O₃ and its suppression on electric field distortion. At this doping level, the interface trap depth and density in PMIA/Al₂O₃ composite paper are maximized, effectively inhibiting charge transport and thus enhancing dielectric strength. Additionally, the optimal sample exhibits a Young’s modulus of 3.65 GPa, tensile strength of 24.6 MPa, and elongation at break of 1.5%. This can be attributed to A-Al₂O₃ bearing more local stress in the insulating paper. However, A-Al₂O₃ tends to agglomerate when its mass fraction exceeds 3%, leading to decreased dispersion in the matrix, reduced effective interface area, lower trap density, and more stress concentration regions, thereby resulting in deteriorated electrical and mechanical properties of composite paper.

To meet the urgent demand for high-performance insulating materials in next-generation electrical equipment, epoxy resin samples were prepared and oxidized with different concentrations of ozone gas. The chemical structure, trap characteristics, and DC breakdown strength of the samples before and after ozone oxidation treatment were then tested and characterized. The results show that after ozone oxidation, the content of C=O and C-OH groups on the surface of epoxy resins increases significantly. After being oxidized with ozone gas at a concentration of 120 mg/L at 80°C for 2 hours, the deep trap energy level of epoxy resin increases from 0.97 eV to 1.04 eV, and its DC breakdown strength improves from 311.94 kV/mm to 395.96 kV/mm.