Research on Thermal Assessment of Cable Trench Based on Heat-flow Coupling and Conveyance Capacity Improvement Measures

The high density of cable laying and the poor cable thermal environment in substation outlet cable trench cause the substation outlet cable trench section to become one of the thermal bottleneck points of the whole cable line. However, there are fewer studies on accurate thermal assessment methods for cables in irregularly clustered countersunk cable trench laying scenarios. To solve the above problems, considering the coupling effect of temperature field and fluid field in the cable trench, this paper establishes a numerical computational model of cable trench with heat-fluid coupling, and carries out the study on the distribution characteristics of temperature field and fluid field in the cable trench. The results show that the temperature difference of each cable conductor in the trench is large, and the resource utilization rate of some lines is not high. To improve the resource utilization rate of cables in the trench, measures to improve the conveyance capacity of cable trench based on high thermal conductivity backfill materials are proposed, and the effect of using different high thermal conductivity backfill materials on the enhancement of the current-carrying capacity of cables in the trench is studied. The research results of this paper can effectively improve the operational safety of substation outlet cable trench.