Study on the Aging Characteristics of Nano‐Al₂O₃ Modified Epoxy Resin in the Case of Electrification in Condensation Environment

The operational stability and safety of switchgear, which is a critical component in power systems for housing and protecting electrical equipment such as circuit breakers, isolating switches, and fuses, are directly determined by the performance of its internal solid insulation materials, particularly epoxy resin. In order to enhance the insulation performance of epoxy resin in a condensation environment, this study delves into the modified epoxy resin by incorporating a nano‐Al 2 O 3 material into the epoxy resin matrix. The original sample and the modified sample undergo testing for varying durations within the condensation environment. Parameters such as condensation state, microstructure, infrared spectrum, resistivity, static contact angle, dielectric loss, and so on are scrutinized to investigate the aging behavior of the samples under the influence of voltage in the condensation environment. The results show that with the increase of charging time, the hydrophobicity of the sample decreases, and the surface condensation degree of the unmodified epoxy resin sample increases, forming a large area of water film. Especially when energized for 6 h, the volume resistivity is 54.30% lower than that of 4 h, and the surface resistivity is 84.27% lower, and the insulation performance has been seriously damaged. However, when the modified epoxy resin sample was electrified for 7 h 36 min, no water film and conductive channel were formed on the surface. The results of scanning electron microscopy showed that no chemical degradation occurred inside the material. The FTIR showed that the characteristic absorption peak of the modified sample was stronger in the range of 650–1000 cm −1 . After 7 h 36 min of electrical aging, the content of benzene ring substituents in the modified samples was higher. The static contact angles of the samples with 1%, 3%, and 5% nano‐alumina were 1.79, 1.86, and 1.83 times higher than those of the original samples, respectively. Through comprehensive comparison of various indicators, it is found that the improvement effect of 1% filling amount is limited; a 5% filling amount may lead to local defects due to slight agglomeration of particles, which may affect the performance. The 3% filling ratio achieves the best balance between performance improvement and structural stability.