The cable joint is the weakest link in the cable line, and the contact resistance between the conductor and the connecting pipe at the aluminum alloy conductor cable joint is the key factor affecting the temperature distribution and failure rate of the cable joint. In order to study the influence of different crimping processes on the temperature distribution characteristics of cable joints, a 35 kV aluminum alloy conductor was used as the research object, and the contact resistance between conductor samples with different crimping percentages and connecting tubes were measured through the contact resistance measurement circuit. The quantitative relationshipes between contact resistance and crimping percentage under two crimping processes of pit pressure and confining pressure were obtained. The electro-thermal coupling model of a cable joint with conductor cross-sectional area of 400 mm2 was established by COMSOL finite element simulation software, and the corresponding relationship between contact resistance and temperature distribution characteristics of cable joint under different crimping processes was studied. The results show that the contact resistance increases with the increase of the crimping percentage. Under the premise of ensuring that the maximum temperature of the long-term operation of the cable does not exceed 90℃ and meeting the mechanical performance requirements, the crimping percentage under the pit pressing process should be controlled at 27.86%-35.44%, and the crimping percentage under the confining pressure process should be controlled at 16.01%-22.21%. The temperature rise curves of the two crimping processes have the same change trend. The highest temperature of the cable core appears at the position of the connecting pipe, and gradually decreases along the axial direction. The temperature of the outer surface of the joint shows a downward trend as a whole, but the temperature of the connecting pipe increases in a small range due to the existence of contact 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 |