Abstract:
This dissertation presents the thermal impact of underground high voltage power cables installed in a cylindrical duct bank and a square tunnel under different environmental conditions. It also proposed methods to enhance the efficiency of underground cables using heat conduction and convection cooling with different mediums.
The heat and ampacity of underground high voltage power cables installed in the cylindrical duct bank were compared with those of underground high voltage power cables installed in the square tunnel using the finite element method, including the comparison of the construction cost of each model. Moreover, the heat and ampacity of medium voltage cables installed in the air-cooled duct bank were also compared with those of medium voltage cables installed in the water-cooled duck bank.
The simulation results showed that in case of no flooding, the underground high voltage power cables installed in the cylindrical duct bank were able to withstand the load better than those installed in the square tunnel. However, in case of flooding, the underground high voltage power cables installed in the square tunnel were able to withstand the load better. It was also found that in the trefoil arrangement, a total of 6 circuits of underground high voltage power cables were able to be installed in the square tunnel, whereas a total of 4 circuits were able to be installed in the cylindrical duct bank, which resulted in the construction cost per circuit of the underground high voltage power cable installation in the square tunnel being cheaper than that of the underground high voltage cable installation in the cylindrical duct bank.