This paper aims to investigate the application effect of two-component polyurea materials in enhancing the insulation strength of transmission line conductor gaps. Firstly, the physicochemical and electrical properties of the two-component polyurea materials were characterized systematically. On this basis, an experimental platform simulating transmission line conductor gaps was constructed, and the effects of coating thickness and gap distance on the breakdown characteristics of the conductor gaps under 50 Hz AC voltage were analyzed systematically. The results show that the glass transition temperature of the two-component polyurea materials is 152℃, exhibiting good thermal stability, the characteristic electric strength reaches 26.21 kV/mm, the tensile strength is 20.2 MPa, and the elongation at break is 515.2%, and it also shows excellent resistance to UV ageing. When the coating thickness is thin (1 mm and 2 mm), the enhancement effect of polyurea materials on the breakdown voltage of transmission line conductor gaps is limited. However, as the coating thickness increases to 3-5 mm, the breakdown voltage of conductor gap increases significantly. In particular, when the gap distance is 20 cm, as the polyurea coating thickness increases from 0 mm to 4 mm, the characteristic breakdown voltage of conductor gap increases from 138.43 kV to 160.94 kV, showing a significant improvement. When the coating thickness reaches 4 mm or more, even if the minimum withstand gap distance shorten to below 3 cm, the polyurea coating still does not breakdown, demonstrating excellent voltage resistance.
| 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 |