Temperature Analysis of HTS Cables in Superconducting DC Energy Pipeline During Short-circuit Fault

Superconducting energy pipelines (SEPs) which can simultaneously transmit liquefied natural gas (LNG) and electricity over long distances are proposed these years. SEPs combining LNG pipelines and high-temperature superconducting (HTS) cables together have higher transmission efficiency. The stable and reliable operation of SEPs during short-circuit faults is important. The HTS cable generating heat may cause the liquid protective medium (LPM) inside the copper former of the cable to boil, endangering the safety of SEP during short-circuit faults. The objective of this paper is to obtain the influence of short-circuit faults on the temperature of HTS cables in SEPs. Three different structures of copper former in HTS cables of a +/- 100 kV/1 kA SEP are investigated including copper rod and two different copper tubes. One inside of the copper tube is vacuum calling internal vacuum copper tube (IVCT) and the other one is LPM calling internal LPM copper tube (ILCT). Simulation results show that the ILCT has the best properties due to its lowest temperature during short-circuit faults. When a fault current of 20 kA transports in the HTS cable for 100 ms, the cross-sectional area of the copper former should be larger than 187.46 mm(2) to ensure safety.