Basalt fibre-reinforced epoxy composites have attracted increasing attention due to their excellent mechanical properties and chemical stability. However, their long-term durability in acidic environments remains a critical challenge, mainly due to interfacial degradation and fibre corrosion. To address this issue, this study proposes a synergistic surface modification strategy based on phytic acid and silane coupling agents, and investigates the influence of different phytic acid mass fractions on the corrosion resistance of basalt fibre composites. By characterising the surface morphology and elemental changes of the fibres, and combining this with tests on weight loss, electrical properties, mechanical properties and thermal stability, the synergistic modification effects and corrosion resistance mechanisms are comprehensively evaluated. The results indicate that the synergistic treatment with phytic acid and KH550 forms a stable complex film and a roughened structure on the fibre surface, effectively enhancing the bond strength between the fibres and the resin. Within the phytic acid mass fraction range investigated in this study, the composite exhibited the best acid resistance when the phytic acid mass fraction was 5

High-voltage wall bushings may overheat during long-term operation, posing a serious threat to power system safety. However, current infrared temperature measurement methods are costly and susceptible to environmental conditions, while thermochromic materials have rarely been applied to high-voltage wall bushings for overheating monitoring. Therefore, in this work, thermochromic microcapsules (TMIs) were incorporated into room-temperature-vulcanized silicone rubber to fabricate reversible thermochromic coatings. The coating properties were then evaluated. The results show that the optimal doping concentration of TMIs is 1 wt%. At this concentration, the coating exhibits favorable electrical performance, tensile properties, hydrophobicity, and thermal conductivity. It also shows a color-change temperature range of 53–59 °C, together with good thermal cycling stability. Field tests demonstrate that the coating can effectively detect overheating defects in high-voltage wall bushings.

Abstract Basalt fibers (BFs) are a promising alternative to conventional glass fibers for reinforcing epoxy composites. However, the interfacial mechanisms governing the adhesion between basalt fibers and the epoxy resin remain insufficiently understood because basalt fibers have a more complex surface chemistry than conventional glass fibers. Here, five commercial BFs were desized to eliminate the effects of surface sizing and were comprehensively characterized by multiple spectroscopic and microscopic techniques. The BFs were found to have a hydroxylated silicate-rich surface with Si, Al, Fe, Ca, and Mg as major constituents. The experimental data were then used to develop a composition-informed atomistic BF surface proxy, which was compared with a hydroxylated silica-rich glass fiber in contact with a crosslinked epoxy resin. The simulation results were benchmarked against water contact angle and microbond debonding experiments. Both the simulation and experimental results indicated that the BFs had a higher interfacial affinity than the glass fiber reference. In addition, its interface with the epoxy resin showed a stronger electrostatic attraction, more negative interaction energy, and denser hydrogen bond network. Meanwhile, the water contact angle and microbond debonding tests indicated it provided better wetting and a higher apparent interfacial shear strength. This work clarifies the adhesion mechanism at the basalt fiber–epoxy interface while defining the limits of simplified atomistic comparisons.

The accumulation of resin-based electrical waste poses significant resource wastage and environmental challenges, with chemical recycling representing a key solution. This study innovatively developed a graded alcoholysis-hydrolysis reaction strategy, enabling both the efficient degradation of anhydride-cured epoxy resin within 1 h under mild conditions and the subsequent reuse of the degradation products in regeneration of new epoxy resins. Central to this work is a uniquely designed benzyl alcohol/K3PO4 recycling system, which enables the closed-loop utilization of not only the epoxy resin but also the system itself, owing to the facile separation of its components. Specifically, the average recovery rates of benzyl alcohol and K3PO4 can reach 80.38 % and 90.95 % over 10 cycles, while the recycling system constructed after 10 cycles using them retained over 80 % of degradation efficiency. Furthermore, the study systematically investigated the synthesis of new epoxy resins by adjusting the proportion of recycled resin. As the recycled resin content increased, the insulation performance of the regenerated resin improved, whereas its mechanical strength and thermal stability exhibited a decline. When the recycled resin content reached 30 wt%, the breakdown strength of the regenerated resin increased by 13.5 % compared to the pristine resin, while maintaining a flexural stress of 72.87 MPa and a glass transition temperature exceeding 100 degrees C. This research provides innovative insights and a theoretical foundation for advancing green decommissioning technologies for resin-based electrical equipment.

External electromagnetic waves are coupled into the high-voltage hall through the holes and slits which will reduce its electromagnetic shielding effectiveness and affect the internal electrical equipment and related tests. In order to explore the influence of holes and slits on the electromagnetic shielding effectiveness of the high-voltage hall, the high-voltage hall was equivalent to a double-layer shielded metal cavity. A simulation model was established and the shielding effectiveness of the double-layer shielded metal cavity with holes was numerically simulated based on the finite element electromagnetic simulation software. The influences of shielding layer spacing, cavity wall thickness, aperture shape, number and arrangement on electromagnetic shielding effectiveness of double-layer metal cavity are studied. The results show that the shielding effectiveness of the cavity with holes decreases with the increase of external electromagnetic frequency; increasing the distance between shielding layers and the thickness of cavity wall can improve the shielding efficiency to a certain extent; circular holes have little effect on the shielding effectiveness of the cavity; the number and arrangement of holes affect the shielding effectiveness of the cavity. The research results have certain guiding significance for the shielding and optimization design of the high-voltage hall.

To improve the poor interfacial bonding between basalt fiber-reinforced composite materials in marine environments and promote their application in large-scale electrical equipment, this paper uses chitosan and polydopamine nanoparticles to create a cross-scale structure on the basalt fiber surface. It also provides a detailed analysis of the infiltration properties of basalt fiber after coating treatment and conducts experiments on seawater corrosion of the composite material (DCS-BFRP). These experiments demonstrate the improved corrosion resistance of the composite. The bioactive coatings were analysed by testing the electrical, mechanical, and physical properties of DCS-BFRP. The results show that, compared to commercial basalt fiber, the coating treatment effectively improves the hydrophilicity and tensile strength, increasing the surface energy by 26.10%, the permeability by 63.52%, and the TFBT strength by 34.82%, while promoting a more prominent interfacial bonding effect. After seawater corrosion, the breakdown strength retention rate of DCS-BFRP reached 72.57%, the dielectric loss factor increased to 1.25%, the bending strength retention rate reached 75.59%, the self-corrosion current density decreased by 24.54%, and it had stronger hydrolysis resistance and higher glass transition temperature. The cross-scale composite bioactive coating combines the advantages of both "rigid" and "soft" transition layers. It resists the erosion of corrosive media on the fibers, improves the seawater corrosion resistance of DCS-BFRP, and provides a reference for the research and development of environmentally friendly special infiltration agents for basalt fibers.

The introduction of dynamic covalent bonds into the structure of epoxy resins can improve the degradation performance of the materials. But to a certain extent, it will affect the insulating properties of the resin, and how to balance the insulating properties and degradation performance has become an urgent problem. In this paper, the effects of different catalysts on the thermal-force-electrical properties of sorbitol-based resins were systematically investigated based on the dynamic ester bonding to construct the resin crosslinking network, and the biobased sorbitol glycidyl ether was used as the resin matrix. The experiments show that the resin system catalyzed by triethanolamine (TEOA) exhibits excellent comprehensive performance, which combines good thermal stability and mechanical properties with excellent electrical properties (breakdown field strength of 44.21 kV/mm and dielectric loss factor of 0.29%). In addition, chemical degradation tests were conducted on the resin systems with different catalysts, and the experiments showed that the produced resins could be degraded in benzyl alcohol and exhibited good degradation performance. This study provides a theoretical basis and technical path for the development of new bio-based electrical insulating materials with both high insulation and degradation properties, which is conducive to the popularization and application of bio-based resins in the field of electrical equipment.

The poor interfacial bonding between basalt fibers and the matrix restricts its application in the field of electrical equipment, while most interfacial treatments face the problems of technical complexity and environmental pollution. In this study, chitosan(CS) and polydopamine (PDA) nanoparticle were synergistically constructed on the surface of basalt fibers in order to form a cross-scale bioactive composite coating, the mechanism of interfacial bonding enhancement was analyzed by characterizing the wettability of basalt fibers, and electrical and mechanical property tests were carried out for the composites. The results showed that DCS-BF-2 exhibited a 53.66 % increase in tensile strength and 63.38 % increase in resin permeability compared to CR-BF, exhibiting more prominent infiltration properties. Compared to the untreated composite CR-BFRP, DCS-BFRP-2 composites showed improved insulating and mechanical properties: the breakdown strength and flashover voltage increased by 16.01 % and 31.93 %, respectively, and the dielectric loss decreased by 33.71 %. In terms of mechanical properties, the transverse tensile strength of DCS-BF-2 fiber bundles was increased by 39.62 %, the flexural strength and interlayer shear strength of DCS-BFRP-2 composites were increased by 19.50 % and 43.9 %, respectively, and the fiber-resin interfacial bonding performance was also effectively improved.

The most widely used bisphenol A-type epoxy resin (DGEBA) in electrical engineering demonstrates excellent mechanical and electrical properties. However, the insoluble and infusible characteristics of cured DGEBA make it difficult to efficiently degrade and recycle decommissioned electrical equipment. In this study, a degradable itaconic acid-based epoxy resin incorporating dynamic covalent bonds was prepared through the integration of ester bonds and disulfide bonds, with itaconic acid as the precursor. The covalent bonding effects on the mechanical, thermal, electrical, and degradation characteristics were systematically evaluated. The experimental results revealed that the introduction of dynamic ester bonds enhanced the mechanical properties and thermal stability of the resin system, achieving a flexural strength of 141.57 MPa and an initial decomposition temperature T5

Silicone rubber insulation materials, with their advantages of weather resistance, water repellency, light weight, and low cost, are widely used in composite insulators in power systems. However, as the number and duration of composite insulator operations increase, and under the long-term exposure to electric fields, mechanical loads, and complex and variable environmental factors, the aging issue of silicone rubber sheds has become increasingly prominent, posing a threat to the safe and stable operation of the power grid. This paper comprehensively reviews the aging characteristics and mechanisms of high-temperature vulcanized silicone rubber materials under the influence of corona discharge, ozone, ultraviolet radiation, acid and alkali, high temperature, surface arcing, and multiple factors simultaneously. Furthermore, various models for predicting the lifespan of these materials are analyzed. Finally, the paper provides an outlook on the aging and lifespan prediction of composite insulators.

Abstract In this study, functional gradient epoxy resin /high-performance composite foam was prepared, and its properties and structural characteristics were studied. By changing the ratio of epoxy resin and high-performance composite materials, the layered control of material density and structure was achieved during the preparation process, thereby achieving optimization of material performance. The results show that the prepared lightweight composite foam based on functionally graded epoxy resin has high strength, high modulus, low density, and excellent energy absorption properties. Through the analysis of the water diffusion leakage current experiment and partial discharge experiment, it is proved that the material has excellent structural characteristics, such as a layered structure. In addition, the effects of functional gradient changes of different types and contents on material properties and structures were also studied, and it was found that appropriate changes can significantly improve material properties and structures. This study may provide a theoretical and practical basis for the research and development of more excellent lightweight composite materials.

To explore sound-absorbing and flame-retardant materials that meet the requirements for double-shielded and double-insulated Faraday cages, polymethyl methacrylate (PMMA) microspheres were incorporated into epoxy resin-based syntactic foam materials for testing and analysis. The addition of PMMA microspheres was found to enhance the electrical, mechanical, sound-absorbing, and flame-retardant properties of the syntactic foam, providing a potential reference for applications in high-voltage hall shielding and sound absorption. Syntactic foams with four concentrations of PMMA microspheres (0%, 0.5%, 1%, and 2%) were prepared. High-voltage breakdown testing, impedance tube testing for sound absorption coefficient, cone calorimetry for flame-retardant performance, and tensile and bending tests were conducted. Results showed that as the concentration of PMMA microspheres increased, improvements were observed in the tensile, bending, flame-retardant, and sound absorption properties of the syntactic foams, while breakdown strength decreased. These findings provide valuable insights into the application of syntactic foam materials in double-insulation, double-shielded Faraday cages.

In order to facilitate the digital transformation of conventional power grid, constructing the digital twin of power equipment is crucial. The primary task of the digital transformation is to build the 3D model of power equipment. However, existing methods cannot achieve digital twin modeling with high fidelity and efficiency. Therefore, a 3D reconstruction method for heterogenous data based on improved Neural Radiation Fields (NeRF) is proposed. By utilizing the infrared-visible image sequence, the spatial domain consistency of the heterogenous data is preserved by the image registration algorithm improved based on restricted matching region strategy (RMRS). Then, in order to focus on the characteristics of the equipment, a deep image matting network (DIM) is designed to eliminate the interference of complex background in the image. The pose of the camera is recovered from the visible images of the power equipment based on Structure From Motion (SFM). Finally, the NeRF is employed to complete the 3D reconstruction of the visible model and temperature field model of power equipment, enabling 3D fusion perception of the 2D heterogenous monitoring data. Experimental results show that this method can realize high-fidelity 3D reconstruction of power equipment within 30 s, which is superior to existing methods in terms of accuracy, modeling speed, automation degree, robustness and lightweight.

Petroleum-based epoxy resin is commonly used in electrical equipment due to its outstanding performance and affordability. However, its non-melting characteristics present challenges for recycling, leading to significant resource waste and environmental pollution. To address this issue, this study prepared and synthesized a kind of vitrimer epoxy resin polymer material based on disulfide bonds with 2,2 '-Diaminodiphenyl disulphide as the curing agent. The research investigated the impact of the curing agent ratio on the resin's structure and properties. The resin was mechanically recovered through hot pressing at high temperature and pressure, and its chemical degradation and recovery were achieved via the reduction reaction of the thiol and disulfide bond. The findings revealed that a curing agent to epoxy group material ratio of 0.75 improved the resin system's electrothermal properties. The electrical insulation property retention rate after hot pressing recovery reached 95 %, with a mechanical property retention rate of 85 %. The disulfide bonds can be reoxidized and crosslinked to realize the recovery and reuse of vitrimer resin degradation solution. Vitrimer epoxy resin based on disulfide bonds is a significant way to realize the environmental protection of epoxy electrical equipment.

Abstract Resistance to hygrothermal aging is the key to the popularization and application of basalt fiber composites in the field of electrical equipment, so it is crucial to develop fiber surface-modified coatings suitable for basalt fibers with excellent hygrothermal resistance. In this study, the performance changes of basalt fiber composite samples treated with four types of surface coatings under artificially accelerated hygrothermal aging test were comparatively analyzed, and the mechanism of different components in the surface coatings was further analyzed. The results showed that the use of epoxy resin emulsion co-mingled with acrylic emulsion as the film-forming agent could significantly improve the mechanical properties of the samples. The use of epoxy resin emulsion co-blended with polyurethane emulsion as the film-forming agent improved the insulating properties and moisture and heat resistance of the samples. Further, the use of 5:1:1 epoxy emulsion, acrylic emulsion, and polyurethane emulsion co-blended as the film-forming agent component can ensure the insulation and hygrothermal resistance of the samples while taking into account the mechanical properties. After 120 hours of wet-heat aging, the breakdown field strength was increased by 22%, leakage current and dielectric loss angle was increased by 10%, and the mechanical properties were also significantly improved compared with the sample with epoxy emulsion as the main film-forming agent. In summary, through the compounding of the film-forming agent emulsion components, the optimization of the moisture and heat resistance of basalt fiber composites can be achieved, and the use of the mass percentage of 5:1:1 for the three types of emulsions blended to prepare the fiber surface coatings is more suitable for the treatment of basalt fibers to prepare the electrician’s equipment.

The design, preparation, and application of high-tech wind turbine blades are crucial for enhancing the performance of wind turbines. With the development of the wind power industry, researching high-quality composite materials suitable for turbine blades has become an urgent issue. Therefore, exploring high-performance composite materials is essential. This study conducted a comparative analysis of the performance changes in carbon fiber/basalt fiber hybrid composite materials with different contents of KH550-modified graphene oxide (SGO) and further examined the mechanism of SGO in the resin matrix. The results indicated that the incorporation of SGO significantly improved the properties of the fiber composites. Specifically, the carbon fiber/basalt fiber hybrid composite material with $1 \%$ SGO not only ensured good electrical conductivity but also maintained favorable mechanical and thermal conductivity properties. Compared to composites without SGO, the tensile and bending strengths increased by $\mathbf{6 4. 0 4 \%}$ and $44.60 \%$, respectively, while the thermal conductivity improved by $\mathbf{1 5. 3 8 \%}$, and electrical conductivity increased by $\mathbf{7. 9 0 \%}$. In summary, by incorporating SGO fillers, the performance of carbon fiber/basalt fiber hybrid composites can be effectively optimized, and the composite material with 1% SGO provides important insights for the development of high-tech wind turbine blade materials.

传统铁横担上使用的绝缘子雷电冲击50％击穿电压(U50％)比较低,存在绝缘导线雷击断线的情况.因此,绝缘性能好、强度高、质量轻的复合绝缘横担开始受到人们的广泛关注,有利于提高配电网的耐雷水平.为了进一步研究复合绝缘横担的防雷性能,本文在不同海拔地区开展雷电冲击闪络试验,得到了10 kV复合绝缘横担的U50％和伏秒特性曲线.并在试验的基础上,利用电磁暂态程序(ATP-EMTP)建立了10 kV线路雷击仿真模型,分析计算复合绝缘横担的耐雷水平.结果表明:在海拔为22 m地区,复合绝缘横担的正、负极性U50％分别为415.43 kV和589.14 kV,而针式绝缘子的正、负极性U50％分别为151.05 kV和200.77 kV.在海拔为2100 m地区,复合绝缘横担的耐雷水平降低了20％左右,但仍远高于针式绝缘子.因此,复合绝缘横担展现出优异的防雷性能,具有广阔的应用前景.

An epoxy-polythiol coating on a cross arm is an effective method to enhance the dielectric strength of air gaps in transmission line towers and reduce the occurrence of bird-related faults. However, epoxy-polythiol dual component raw materials could not achieve the prescribed stoichiometric ratio of 1:1, affecting the protective performance of the formed insulation layer. This study characterizes the cured systems of epoxy-polythiol with imbalance stoichiometry using Fourier-transform infrared spectroscopy and scanning electron microscopy. Tests were conducted to analyze parameters of the epoxy-polythiol curing system, including breakdown strength, cure time, thermal conductivity, water absorption rate, and mechanical properties. Results demonstrate that nonstoichiometric conditions reduce the curing time, breakdown strength, thermal conductivity, and water absorption of the epoxy-polythiol curing system. However, a slight increase in the equivalent amount of the curing agent improves the mechanical properties of the cured products.