Comparison between Simulation and Experimental Results of Liquid Nitrogen Coolant Distribution in a 66-kV 40-m Model HTS Power Cable System Experiencing Short-Circuit Accidents

In this study, a computer program was developed to simulate the temperature and pressure distributions of a liquid nitrogen (LN) coolant in a higherature superconducting (HTS) power cable. This program is important for realizing a practical HTS power cable. According to the Japanese criterion for a 66-kV power-transmission system, in a worst case short-circuit accident, a fault current of 31.5 kA may flow in a 66-kV cable system for 2 s. In addition, when a short-circuit accident occurs, the temperature and pressure of an LN coolant increase rapidly The temperature behaviors of the cable cores and coolant were analyzed by solving the nonlinear partial differential heat-conduction equations in the cable cores by considering the energy balance of the heat flow by using the finite-difference method. Moreover, the pressure behaviors of the coolant in a cooling system were analyzed, considering the density and volume behaviors of the coolant. The simulation results for the 66-kV 40-m model cable qualitatively reproduced the experimental results satisfactorily.