Error analysis on calculating conductor temperature based on outer sheath temperature of cable

Calculating conductor temperature of HV cable accurately has been concerned by cable design, operation and management, and power scheduling. In order to calculate conductor temperature accurately based on surface temperature and aluminum sheath temperature, thermal circuit was put forward. We designed temperature rising test for step current of 110 kV XLPE single-core cable which was buried in soil. The experimental data was analyzed based on thermal circuit, the results show: comparing conductor temperature value calculated by outer sheath temperature and measured value, the error is among 5%, and comparing conductor temperature value calculated by aluminum sheath temperature and measured value, the error is also among 5%, and range of their difference is -0.3°C-1°C. That is to say, it is available to calculate conductor temperature accurately based on surface temperature, which also can be applied in engineering.