Analytical Calculation Method for Steady-state Current Capacity of HVDC Cables

Abstract

The accurate calculation of the steady-state current capacity of HVDC cable is of great significance for the full utilization of its transmission capacity. Firstly, the method of calculating the steady-state current capacity of the HVDC cable is proposed. The method also considers permissible maximum long-term conductor temperature (PMLTCT) and permissible maximum insulation temperature difference (PMITD). Secondly, the steady-state carrying capacity of ±160 kV cross-linked polyethylene DC cable is calculated by this method, and verified by the finite element method. Finally, the influence of ambient temperature, PMLTCT and PMITD on the steady-state current capacity of DC cable are studied. It is found that the current carrying capacity curves of DC cable which consider PMLTCT and PMITD may intersect with ambient temperature change. If the ambient temperature is higher than intersection temperature, the steady-state current capacity is determined by PMLTCT, and otherwise, the steady-state current capacity is determined by PMITD.