Effect of Different Operational Conditions on Distribution of Temperature Field in HV Directly Burial Power Cables

Power cables are indispensable components in power transmission lines. Directly buried installation is one of the main laying methods in urban and rural areas. The effect of different operational conditions is hard to calculate by analytical method. Using finite element method, this paper established a 110 kV XLPE power cable electromagnetic-thermal model and calculated its ampacity, and analyzed its temperature field under different operational conditions including ambient temperature, soil thermal conductivity coefficient and directly burial depth. With comparison to the IEC-60287 Standards guide, the accuracy of this model had been verified. The results showed that the cable conductor temperature and surface temperature approximately linearly increased along with the ambient temperature and buried depth rising. The temperature of the cables reduced with the soil thermal conductivity coefficient increasing. It had been found that the operational condition had a great effect on distribution of temperature field of directly burial power cables, which provided a valuable instruction to state grids operation and maintenance.