Real-time calculation of three core cable conductor temperature based on thermal circuit model with thermal resistance correction

The conductor temperature of cable in operation is the basis for determining whether the cable reaches the ampacity. For the three core cable, it is difficult to calculate the thermal resistance of the filling layer accurately due to its irregularity shape, resulting in a large error in the temperature calculation of the cable conductor using the thermal circuit model. Therefore, it is proposed to calculate the thermal resistance of the filling layer by temperature field, and then calculate the conductor temperature by thermal circuit model. The conductor temperature of three core cable in steady state and transient state is calculated using the thermal circuit model, and the results are compared with the finite element simulation results. The results show that the maximum temperature difference of the two methods is about 2°C, showing a high accuracy of the proposed method. Finally, the effectiveness of the method is verified by the experimental data, the results show that the relative error between the calculated temperature of cable conductor and the experimental data is within 10%, which meets the needs of engineering application. The research results of this paper contribute to improving the operation and maintenance of three core cables.