Epoxy resin paper-impregnated bushings, as critical insulating components in power transformers, are subjected to complex electric fields, thermal fields, and mechanical stresses over extended periods. Their performance stability is directly linked to the safe operation of transformers. Given the significant costs associated with their production, reliability verification is a crucial aspect of their design and manufacturing process. This study employs the finite element simulation technology to systematically investigate the electric field distribution characteristics, thermal field distribution characteristics, and seismic performance reliability verification methods of epoxy resin paper-impregnated bushings. The simulation and calculation results indicate that for bushings with rated voltages of 40.5 kV, 72.5 kV, and 126 kV, the maximum radial electric field strengths are 1.38 kV/mm, 2.74 kV/mm, and 3.0 kV/mm, respectively, with axial electric field strengths all below allowable values. The insulation margin meets the 1.5 standard requirements. Under short-circuit conditions, the thermal stability analysis of the bushings reveals that the final conductor temperatures are all below 180 °C, indicating sufficient safety margins. All three types of bushings comply with the design requirements for an 8-degree earthquake intensity and are capable of effectively withstanding seismic loads. This research provides a theoretical foundation for the development and application of epoxy resin paper-impregnated bushings, offering a significant engineering application value in enhancing the safety and stability of transformers and power systems.

The aging and failure of transformer bushing seals under multi-factor effects are significant causes of oil leakage incidents. However, their failure mechanisms under combined environmental stressors remain inadequately understood. This study presents a comprehensive investigation into the aging behavior and failure mechanisms of nitrile rubber (NBR) and fluoroelastomer (FKM) sealing materials subjected to single and multi-factor aging conditions, including thermo-oxidative, hygrothermal, hygrothermal–compression, and hygrothermal–compression–salt environments. NBR undergoes severe degradation under multi-factors, dominated by additive loss and molecular chain crosslinking. At high temperatures, large-scale molecular chain scission occurs, along with increased compression set, microscopic morphological damage, and filler precipitation. In contrast, FKM exhibits excellent stability thanks to its C-F main chain. Stress synergy significantly accelerates the failure of both materials. These findings highlight the need for multivariate analysis to support reliable condition assessment and lifetime prediction and to inform sealing material selection and proactive grid maintenance.

Composite insulated cross-arm (CICA) can be used in high voltage transmission lines to substitute composite insulators with iron cross-arms. In addition to its excellent insulation performance, CICA can also save on transmission corridors, etc. Nevertheless, due to the horizontal arrangement, CICA bears complex mechanical stresses in addition to the high temperature and humidity environmental factors. The aging mechanism under the multifactor coupling effect is studied in this paper based on a 110 kV CICA. The test results of the interface property show that the hygrothermal factor is the main reason for aging. In addition, stress affects the interface properties by promoting moisture penetration. The interfacial current changes can be divided into three stages: the voltage-current synchronous growth stage, the voltage-continuous current plunge stage, and the interfacial breakdown stage, during the multi-factor aging process. Besides, the CICA experiments show a synergistic effect between the hygrothermal and mechanical factors in the deterioration process of the silicone rubber and the core rod. Constant force and high and low circumferential cyclic forces mainly affect the mechanical properties. This work can be helpful for the application and promotion of CICA.