Effects of High Thermal Conductivity on Power Cable Ampacity with LDPE/BN Composites

Insulating material used in cables is usually polymer with excellent electrical properties but terrible thermal conductivity. Insulation-related thermal problems set a limit to the ampacity of cables. Improving the thermal conductivity of insulation may be beneficial to improve heat dissipation of cable system and enhance its ampacity. In this paper, a numerical simulation model is employed by finite element method (FEM), and the cable ampacity is calculated by a modified iteration method to research the relationship between the thermal conductivity of insulation and the cable ampacity. Meanwhile, a range of low-density polyethylene (LDPE) based composites filled with hybrid boron nitride (BN) particles at different loadings are prepared to get reasonable model parameters. The results show that the thermal conductivity of BN filled LDPE composite is improved greatly. With increasing the thermal conductivity, the cable core temperature is reduced obviously with the given load current, and the temperature field distribution in insulation becomes more uniform, which imply that the improved thermal conductivity of insulation contributes to the improvement of cable ampacity.