Influence of no-load superconducting cable´s input on distance protection

The introduction of the superconducting cables into power system, effectively reduce the loss of power transmission, could affect conventional lines´ distance protection at the same time. Through theoretical analysis as well as simulation, this paper focuses on distance protection´s directivity and demonstrates that the impedance relays on conventional lines could tripping off when no-load superconducting cables are put into the protection´s opposite direction of regular lines. To avoid such error action, this paper puts forward the corresponding solutions and removes barriers for the superconducting cables´ application into power system.