Research In The Insulation Of The Cryostat, Terminator And Cryostat Connecter Of HTS Cable

The construct of HTS cable is introduced; the characteristics of different insulation and the properties, both in room temperature and cryogenic temperature, of several materials are investigated. A 75m, 10.5kV /1.5kA three-phase AC superconducting cable has been constructed and tested in grid in the end of 2004. The insulation characteristics of both cryostats and termination of HTS cable are introduced. The 75m cryostat for the cable consists of three cryostats of 25m, which are in series connected. The insulation of the 75m, 10.5kV/1.5kA three-phase AC superconducting cable is processed on the cryostats not the superconducting conductor. Both the cryostat connecter and terminator are insulated. The insulation design of the HTS cable itself and both the connecter and the terminator are introduced. The distribution of the electric field are calculated and analyzed both in numerical method and in resolution method, the peak value of electric field are positioned. Based on this analysis, some methods to minish the electric field gradient are suggestedand has been put in practice. The calculation and analysis are very helpful for the design of the insulation of the connector and the termination of the HTS cable. A model cable intergrator including the cryogenic and both the joint of the cryostats and termination has been developed before the processing of the insulation of both the connecter and the terminator. The insulation of the insulation of the model intergrator have passed both the 4h 35kV AC withstand voltage test and 1min 42kV AC withstand voltage test. The insulation of the cable has been finished and tested. It has passed the AC 35kV withstand voltage test and partial discharge test. The value of partial discharge under AC 15kV voltage is less than 1 pc. The insulation of the 75m, 10.5kV /1.5kA three-phase AC superconducting cable system also has been tested by the local electric power department before the HTS cable been connected in grid. The 75m, 10.5kV /1.5kA three-phase AC superconducting cable system has been connected in grid and has begun to supply power for Gansu Changtong Cable Science & Technology Co., Ltd. The sytem is stable and reliable.