Protection Scheme for Kilometer-Level High Temperature Superconducting Line

This paper introduces the system structure of the kilometer-level superconducting cable demonstration project of Shanghai and presents an overall scheme of relay protection configuration for superconducting lines. The scheme takes differential protection and quench protection as the primary protection for quick isolation of the internal faults, and takes over-current protection as the back-up protection for timely removal of superconducting cables when there are line faults or external faults after the differential protection is out of service, ensuring the safety of the superconducting cable equipment. Also, the feasibility of application of reclosure and inverse time over-current is discussed. Aiming at the wiring method of the kilometer-level superconducting cable demonstration project of Shanghai, this paper introduces the tripping and closing logic and matching mode of breakers on both sides of the superconducting line, so as to realize a consistent supply of electricity when the superconducting cable is in fault. Non-electric quantity information such as temperature, pressure, flow rate, etc. is an important monitoring indicator for the state of the superconducting cable. The application of non-electric quantity status information on both ends of the kilometer-level superconducting cable line in relay protection device is introduced.