Thermal Analysis of Power Cable in Tunnel Considering Different Laying Conditions

The thermal analysis of the power cable in the tunnel is important to evaluate ampacity, improve service life and ensure operation safety. However, the existing research mainly focuses on the influence of installation mode and installation position on the hottest cable and is less concerned about other cables. This paper establishes the temperature calculation model based on Ohm's law and thermal-flow coupling field, considering power cables laid in free air and closed space. The variation rules and influence factors of cable temperature under rated load conditions and different laying conditions are analyzed. The results show that the operation temperature is related to the proximity effect, heat radiation effect, and heat convection effect between cables and other facilities. When the cable is close to other facilities, the maximum temperature deviation is more than 7.0 K. With the increase in distance, the interaction between cables and other facilities gradually attenuates, and the temperature tends to be the condition of the single cable laid in free air. The research results provide suggestions for the modeling method selection of numerical analysis of cable temperature.