Dynamic experiment for the magnetothermal stability of a 110 kV/3 kA cold dielectric high-temperature superconducting cable with an impact of fault current in power system

Since higherature superconducting (HTS) cables have attracted significant attention for their low losses (30% of normal power cable), large capacity, and small size, they can be used for electric power transmission for efficient use of energy in power systems. However, they are often subjected to overcurrent impact caused by a short-circuit fault when they are used in a transmission system. In this overcurrent impact, a large amount of Joule heat is generated, which can damage the stability of HTS cables and influence the efficiency of power transmission. A dynamic experimental test of a 110 kV/3 kA prototype HTS cable under a fault current impact has been carried out by China Electric Power Research Institute. A magnetothermal stability experimental system with a pulsed current power source (25 kA for 0-1 s) and a high-precision National Instruments digital data acquisition system have been set up. The transient current and temperature of each superconducting layer in the HTS cable have been tested and investigated considering the overcurrent impact of 25 kA for 1 s. Numerical simulations were also performed on the prototype cable using a computer program on the basis of a finite-element method and an electrical circuit model. The results have shown that the currents of the conducting layers decrease while the temperature increases in the HTS cable, and the former can withstand most of the fault current. Therefore, the proposed experimental system is proved to be effective for testing HTS cables with overcurrent impact.