In order to solve the problem of significant decrease of insulation performance caused by condensation on the surface of switchgear insulation components in high temperature and high humidity environments, in this paper, E51 epoxy resin was modified by adding different mass fractions of nano-alumina, and the electrical properties of the modified samples were tested. The results show that the resistivity and dielectric loss factor of the modified epoxy resin decrease slightly. In the condensation environment formed under different temperature difference, the flashover voltage of the modified epoxy resin clean sample with nano-alumina mass fraction of 1%, 3%, and 5% is 56.7%, 84.5%, and 66.7% higher than that of unmodified sample, respectively. With nano-alumina mass fraction of 1%, 3%, and 5%, the flashover voltage of the contaminated sample is 10.8%, 17.3% and 14.9% higher than that of unmodified sample, respectively, and the effective value of the leakage current is 40.3%, 46.6% and 45.8% lower than that of unmodified sample, respectively. In summary, the electrical properties of modified epoxy resin samples containing 3% nano-alumina are improved significantly.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |