Under the "dual carbon" goals, traditional epoxy resins, which are depend on petrochemical feedstocks and are non-recyclable, have severely hindered the current transformation of power systems. Developing low-carbon and environmental friendly epoxy resins has become a research focus. This study adopted a “rigidity-flexibility” balancing strategy to prepare a bio-based epoxy resin with Schiff base dynamic covalent bonds cured directly by an aldehyde-terminated bio-based epoxy crosslinker and a diamine. Its mechanical properties, insulation performance, and property changes before and after multiple recycling processes were investigated. The results show that the novel epoxy resin achieves a tensile strength of 70.1 MPa and an electric strength of 130 kV/mm. This dynamically cross-linked epoxy resin can be effectively reprocessed and recycled via solvent, retaining a tensile strength of 58.8 MPa and an electric strength of 111 kV/mm after multiple reprocessing cycles.

The environmental impact of greenhouse gases has garnered widespread global attention, and the low-carbon transformation of power equipment is of great significance for achieving the carbon peaking and carbon neutrality goals. Based on the life cycle assessment (LCA) method, we focused on the raw material acquisition, product manufacturing, and waste disposal stages of an 800 kVA epoxy cast dry-type transformer, and evaluated its carbon footprint and environmental impact from a material perspective. The Monte Carlo simulation method based on the triangular distribution and Sobol sequence was adopted to conduct uncertainty analysis on the carbon footprint results, so as to assess the uncertainty of carbon emissions from key resources. Based on two environmental impact assessment methods CML-IA baseline 2001 and ReCiPe 2016, the environmental impact degree of transformer at each stage was comprehensively evaluated. The results show that the total carbon footprint of the transformer is 8 996.25 kgCO₂e, with the raw material acquisition stage contributing the most to the product carbon footprint, reaching 7 186.51 kgCO₂e. Copper, silicon steel sheets, and epoxy resin are the main carbon sources, accounting for 42.87%, 31.17%, and 23.93%, respectively. Both sensitivity analysis methods are consistent with the actual situation, but the 95% confidence interval obtained by the Sobol sequence method is significantly wider than the [8 691.92, 9 311.68] kgCO₂e of the triangular distribution, demonstrating a more sufficient ability to express uncertainty. The first-order sensitivity indices of the two key resources, epoxy resin and power consumption, calculated by the two methods are 0.460 and 0.499, respectively, indicating that they have the most obvious impact on the carbon footprint of the transformer. The environmental impact assessment results of CML-IA baseline 2001 and ReCipe 2016 show that the raw material acquisition stage dominates all environmental damage categories, with the most significant impact on marine ecotoxicity. The core causes are the heavy metal emissions during the mining and processing of copper and silicon steel sheets, as well as the organic pollutants released during the synthesis of epoxy resin.

This study aims to prepare high-performance polypropylene (PP) insulation materials and investigate the enhancement mechanism of their properties. By combining in-reactor alloying and blending modification technologies, PP insulation materials with elastomer mass fractions of 20% to 30% for high-voltage cables were prepared. The interfacial compatibility between the elastomer and PP matrix and its impact on the performance of the PP insulation material were studied. The results show that the propylene-based elastomer can effectively improve the interfacial compatibility between elastomers and PP matrix, thereby reducing interfacial defects. The "bimodal" particle size distribution design of elastomers successfully balances the dual effects of the elastomer on mechanical toughness and electrical strength of PP insulaton materials, realizing the synergistic improvement in mechanical toughness, electric strength, and thermal stability, demonstrating excellent overall performance. Moreover, the prepared PP cable material possesses good processing adaptability.

This study systematically investigated the effect of the type and content of ethylene-butyl acrylate (EBA) copolymer on the properties of linear low-density polyethylene (LLDPE)-based non-crosslinked semiconductive shielding materials. A series of shielding material samples were prepared, and their physicochemical properties, volume resistivity, and mechanical performance were characterized. The results show that the incorporation of EBA significantly improves the processability and electrical conductivity of the shielding material. When the mass fraction of EBA in the matrix resin increases from 0 to 15%, the melt flow index of the shielding materila increases from 0.95 g/10 min to 1.15 g/10 min, while the volume resistivity decreases from 11.68 Ω·cm to 8.69 Ω·cm. However, the addition of EBA also leads to reduction in crystallinity and mechanical properties of the shielding material. Among the samples modified by different types of EBA, the 35BA40-modified sample exhibits optimal electrical conductivity and processing flowability, whereas the E2770-modified sample shows superior mechanical performance.

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.

With the development of power electronic equipment toward high-frequency, miniaturization, and integration, the performance of traditional polypropylene (PP) film materials is gradually becoming insufficient to meet the requirements of modern capacitors for high electric strength, low dielectric loss, and long service life. To address this, the modified PP film materials with different grafting rates were prepared by grafting 4-methylstyrene onto polypropylene (PP) via an aqueous suspension grafting method, and the effect of grafting rate on their comprehensive properties was studied. The results show that the optimal swelling time and reaction time of grafting modification are 120 minutes and 150 minutes, respectively. With the increase of grafting rate, the heating melting curve tends to shift towards lower temperatures, while the cooling crystallization curve tends to shift towards higher temperatures. When the grafting rate is 0.88%, the modified PP exhibits the highest tensile strength and elongation at break, with the electric strength reaching a maximum value of 400.8 kV/mm, and the trap density reaching a maximum value of 9.52×10¹⁹ m^-³·eV^-1, which is nearly 3.8 times higher than the maximum trap energy level density of pure PP material.

Polyethylene is the preferred material for lithium battery separators, its hydrophilicity directly determines the electrolyte ion transmission efficiency and the interface stability of battery. To improve the hydrophilicity of polyethylene separator, we employed atmospheric pressure plasma jet treatment using 3-aminopropyltriethoxysilane as a reaction medium to activate and modify the separator surface. The effects of treatment time and treatment distance on the hydrophilicity of the separator surface were studied by experiments, and the optimal treatment conditions and effects were obtained. The surface morphology and chemical structure of the separator were characterized using scanning electron microscopy and X-ray photoelectron spectroscopy to analyze the effect of plasma treatment on its micro-physical and chemical properties, thereby analyzing the mechanism of its performance improvement. The results show that with the increase of treatment time and distance, the hydrophilicity of the separator increases at first and then decreases. The optimal performance is achieved at a treatment time of 6 min and a treatment distance of 20 mm, where the water contact angle of the modified separator approaches 0°, achieving super-hydrophilic effect. After treatment, the separator tends to be hard and brittle, and its thermal shrinkage rate decreases by 51%. The plasma jet introduces -NH₃⁺ hydrophilic groups onto the separator surface, and through etching, cross-linking, polymerization, and deposition, a nano-silicon oxide film with larger pores is formed on the material surface, which significantly enhance the surface hydrophilicity and thermal shrinkage resistance of seperator.

This research aims to synergistically enhance the thermal and mechanical properties of epoxy resin to cope with the risk of insulation failure under long-term electrical-thermal-mechanical multi-field coupling conditions. Biphenyl liquid crystal epoxy resin (BLCER) was introduced into the bisphenol A type epoxy resin (E-51) matrix, and liquid crystal-modified epoxy resin was obtained through melt blending followed by curing. The thermal and mechanical properties of the modified resin were tested, and the toughening and thermal conductivity modification mechanisms of BLCER on the resin matrix were analyzed. The results show that the addition of BLCER can enhance the thermal stability and thermal conductivity of the modified resin. When the mass fraction of BLCER reaches 20%, the thermal conductivity of the modified resin increases to 0.382 W/(m·K), which is 2.26 times higher than that of pure E-51. The mechanical properties of the material increase with the content of BLCER. When the mass fraction of BLCER reaches 20%, the tensile and flexural strengths of the modified resin reach 90 MPa and 120.9 MPa, respectively, and the impact strength reaches 40.1 kJ/m², which are significantly higher than those of pure epoxy resin.