Aiming at the problem that the poor heat dissipation effect of the cable laying in piping leads to the cable line appear ampacity bottleneck, we use the 2×3 piping laying of 110 kV power cable with two loops as research object. The changes of cable ampacity before and after backfilling low thermal resistance materials in the pipes was studied through thermal circuit models and large current tests, and the relationship between the ampacity of cable and the thermal conductivity of backfill material was analyzed based on finite element simulation model. The results show that when two circuits of 110 kV 630 mm2 cables are laid with 2×3 rows of pipes, compared with the case without backfilling in the pipes, the ampacity of cables after the pipes are backfilled with low thermal resistance materials increases by 25.22%. With the continuous increase of thermal conductivity of the backfill material, the ampacity of cable also continues to increase, but the increase rate is slower and slower, and the ampacity of cable tend to be stable eventually. When the thermal conductivity of backfill material increases from 1 W/(m·K) to 7 W/(m·K), the increase rate of cable ampacity is 8.99%. When the thermal conductivity of backfill material increases from 7 W/(m·K) to 13 W/(m·K), the increase rate of cable ampacity is only 2.00%.
| 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 |