In hot and humid environment, composite insulators with interface defects are more prone to occur serious accidents such as decay-like breakage and interface breakdown. However, there is a lack of studies on the interface ageing mechanisms of composite insulators with core-sheath interface defects under hygrothermal environment. In this paper, composite insulator short samples with different interface defects were subjected to hygrothermal ageing. The temperature rise and discharge results of each sample were compared under conditions of moisture absorption and dry condition. The influence of hygrothermal environment on the performance of composite insulators with interface defects was studied through dissection observation, microscopic morphology observation, and surface elements and functional groups analysis. The results show that the insulator interface defects will expand into interface failures under the action of heat and humidity. Partial discharge and polarization loss of moisture at the interface will trigger abnormal heating faults, and the temperature rise caused by metal defects is significantly higher than that of other defects. As the interface defects gradually expand, epoxy resin undergoes oxidation and decomposition from interface to interior, and the glass fibers exposes and deteriorates.
| 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 |