The Optimized Heating Current Strategy for Temperature Control of HVDC Cables during Load Cycle Tests

Load cycle test is a critical evaluation method for assessing the long-term thermal performance of full-scale HV and EHV cables. Optimizing the application strategy of the heating load current to fulfill the requirement of HVDC cables both on conductor temperature and insulation temperature gradient during load cycle tests can improve the experiment efficiency and guarantee the test effect. In this paper, an electro-thermal field coupling model of the DC cable is set up by finite element analysis (FEA) modelling system (COMSOL Multiphysics) and the method to determine the applicable heating current within the temperature control boundary conditions is proposed by using the optimization module of COMSOL Multiphysics. One feasible configuration of heating currents determined by this method is then applied on a 320 kV DC XLPE cable laid in air, and the transient thermal and electrical field distributions of it during the load cycle test are simulated and analyzed. The result shows that the conductor temperature and insulation temperature gradient remain within the preset boundary condition, which verifies the optimized heating current strategy proposed in this paper.