Temperature Calculation and Measurement on Power Cable Conductor Based on Equivalent Thermal Circuit and BOTDA

China's Hainan network system 500kV AC submarine cable has the world's largest length and the second largest capacity in the world, with very important political and economic significance. The surface temperature of the power cable is estimated to calculate the internal conductor temperature and the current rating capacity. Firstly, the principle of testing is introduced, which is the principle of temperature testing of the optical cable bundled on the power cable surface using the Brillouin optical time domain reflectometer tester. Secondly, the power cable current rating experiment was designed. The power cable is bundled on the surface of the 10 meter optical cable. The BOTDA distributed temperature tester is attached to both ends of the power cable to monitor the power cable surface, record the surface temperature of the power cable, and route the power cable through cable heater. Use the power cable heat cycling test system to heat the power cable, the temperature of cable conductor is monitored by a thermocouple, and clamp current meter monitors the current rating capacity of the conductor, changes the regulation value of the through transformer, recording the temperature and load of the power cable conductor. Finally, this method of bundling the optical cable on the power cable surface was verified, which provided an experimental basis for submarine cable temperature monitoring.