Development of high-temperature superconductor cables for high direct current applications / / Alan Preuß.

• VerfasserIn: Preuß, Alan,
• Place / Publishing House: Karlsruhe : : KIT Scientific Publishing,, 2021.
• Year of Publication: 2021
• Language: English
• Physical Description: 1 online resource (194 pages)

A design process for HTS DC cables was developed for high current applications. Based on the design process, a 35 kA HTS DC cable demonstrator was developed. The superconducting elements of the demonstrator were manufactured and tested individually at 77 K. Afterwards, the demonstrator cable was ass...

Table of Contents

• 1 Acknowledgments . I
• 2 Zusammenfassung III
• 3 Introduction . 1
• 4 Basics of high temperature superconductivity 3
• 4.1 Critical values of superconductivity 3
• 4.1.1 Critical temperature . 4
• 4.1.2 Critical current density . 4
• 4.1.3 Critical magnetic field 6
• 4.2 Technical superconductors . 6
• 4.3 Second generation HTS 7
• 4.3.1 Structure and properties of REBCO wires . 9
• 4.3.2 Critical current magnetic field dependence 10
• 4.3.3 Critical current temperature dependence . 11
• 4.3.4 Critical current strain dependence . 13
• 5 State of the art of REBCO high current transmission 15
• 5.1 High current applications . 15
• 5.2 High current conductor concepts . 16
• 5.2.1 Co-axial winding concept 16
• 5.2.2 Roebel concept 18
• 5.2.3 Stack concepts 19
• 5.2.4 Cross Conductor . 21
• 5.2.5 Concept comparison . 22
• 5.3 Summary of HTS DC cable projects 25
• 6 Conceptual design of REBCO DC cables . 29
• 6.1 Temperature and pressure proile . 29
• 6.2 Fault mitigation 32
• 6.3 Critical current calculation 33
• 6.4 Electric insulation . 34
• 6.5 Cable losses . 36
• 6.6 Strain 38
• 6.7 Design procedure 40
• 6.8 Design study of 35 kA REBCO DC cable demonstrator . 48
• 7 HTS CroCo Manufacturing 55
• 7.1 Thermal stability of REBCO tapes . 55
• 7.1.1 Experimental setup and procedure . 56
• 7.1.2 Results 57
• 7.1.3 Conclusion 63
• 7.2 CroCo manufacturing process and machine . 64
• 7.3 Manufacturer qualication . 66
• 7.4 CroCo strand manufacturing . 70
• 7.4.1 Preliminary CroCo manufacturing tests 70
• 7.4.2 CroCo manufacturing 71
• 7.4.3 CroCo residual production strain 73
• 7.4.4 CroCo jacket . 75
• 8 35 kA REBCO DC cable test . 79
• 8.1 Single CroCo characterization . 79
• 8.1.1 Electric CroCo characterization . 79
• 8.1.2 Microscopic characterization 85
• 8.1.3 Current distribution simulation . 88
• 8.2 Demonstrator cable setup . 89
• 8.2.1 Cryostat . 89
• 8.2.2 35 kA cable demonstrator 91
• 8.2.3 Current source and quench detection 92
• 8.2.4 Data acquisition . 94
• 8.3 Demonstrator cable test 94
• 8.3.1 Cryostat cool down and warm up 94
• 8.3.2 Cable test . 96
• 8.3.3 CroCo performance post cable operation . 100
• 8.4 Chapter summary and outlook 103
• 9 Application of HTS DC cables in aluminum plants . 105
• 9.1 Aluminum production . 105
• 9.2 Superconducting cable systems within aluminum plants 106
• 9.2.1 Superconducting cable use cases 106
• 9.2.2 Cryogenic system 107
• 9.2.3 Current leads . 110
• 9.3 Primary circuit . 111
• 9.4 Secondary circuit 115
• 9.5 Aluminum bus bar . 118
• 9.6 System comparison . 120
• 9.6.1 General properties 120
• 9.6.2 Annual losses and operating cost . 120
• 9.6.3 Investment cost 123
• 9.7 Chapter summary . 128
• 10 Summary and outlook . 129
• A Appendix 131
• A.1 Order of magnitude estimation of the coolant friction 131
• A.2 Relevant copper material properties for the use as stabilizer material . 131
• A.3 Temperature incremental code to calculate stabilizer cross section 132
• A.4 Darcy friction factor for smooth and corrugated pipes . 134
• A.5 Critical current calculation of manufactured CroCos 135
• A.6 Thermal contraction of superconducting cables . 137
• A.7 Cryocooler capacity maps . 138
• B List of abbreviations . 141
• C List of symbols . 145
• D Publications . 149
• E Bibliography 151.