Testing of Single Phase Short Sample Cable Core Made with YBCO Conductors C. S. Weber, V. Selvamanickam, Y.Y. Xie - SuperPower, Inc. T. Masuda, H. Yumura - Sumitomo Electric Industries Session # 4LW1 HTS Solutions for a New Dimension in Power 26 Applied Superconductivity Conference August 31, 26
Presentation Outline Process development of YBCO conductors for cable applications Width Overcurrent Protection Mechanical Properties Testing of 1Φ YBCO cable cores Benefits of thinner substrates Status of 1km wire delivery to SEI 26 Applied Superconductivity Conference Seattle, WA 2
Albany Cable Project Configuration Phase I: BSCCO Phase II: 3m YBCO 26 Applied Superconductivity Conference Seattle, WA 3
Specifications for 2G Conductor Conductor Width Cable Former Bend diameter Critical tensile stress Hermetic test Spiral Winding 4 mm 16 mm diameter 1 mm 15 MPa No Ic & thickness change after 1 atm of LN 2 for 24 hours 95% Ic retention after winding on 16 mm former with 13 mm pitch Albany Cable is a very compact cable made with practical 4 mm wide conductor 26 Applied Superconductivity Conference Seattle, WA 4 *AMSC presentation, DOE Peer review 23
Slitting to 4 mm width before copper stabilizer application To use Surround Stabilizer, tapes have to be slit prior to copper plating i.e. directly on Ag overlayer. Two 4 mm wide tapes slit from a 1 cm wide, 8 m long tape. 16 14 Critical current (A/cm) 12 1 8 6 4 2 1 2 3 4 5 6 7 8 Original 1cm-wide After Cu-plating Position (m) After slitting Only 1% average reduction in Ic (sum of both 4 mm tapes) after slitting No degradation in Ic after electroplating copper stabilizer Slitting directly on silver overlayer shows the robustness of our coated 26 Applied Superconductivity conductor Conference Seattle, WA and enables Surround 5 Cu Stabilizer application
Electroplating process demonstrated for copper stabilizer application on coated conductors An advantage of electroplating is Surround Stabilizer application i.e. copper on all sides in 1 step. HTS is completely encased and protected Rounded edges could be important for high-voltage applications Surround Cu stabilizer Single side Cu stabilizer Conductor Type Single side Cu (4 microns) Surround Stabilizer Cu (2 microns all sides) Burn-out after over current test Current & Power required to burnout conductor Conductor 1 Conductor 2 233A 18.6W/cm 2 279A 33.3W/cm 2 Surround Copper Stabilizer provides higher over current handling capability for coated conductors 25A - 18.1W/cm 2 277A 27W/cm 2 26 Applied Superconductivity Conference Seattle, WA 6
Current (A) Overcurrent handling capability of surround stabilizer structure verified with pulsed currents Temperature (K) 25 2 15 1 5 16 14 12 1 8 6 Ic = 54A, 1 s Pulse, 8 s Hold, 2nd pulse, Peak current (I p ) = 193A, I p /I c =3.57 1 2 3 4 5 6 7 8 9 1 11 Minimal Ic degradation and no tape burn out even at overcurrent levels of 9 times Ic with 3 ms pulses and 3.5 times Ic with 1 s pulses 26 Applied Superconductivity Conference Seattle, WA Time (s) Current 5cm 1cm 1 2 3 4 5 6 7 8 9 1 11 Time (s) TC1 TC2 TC3 Power5cm Power1cm 7.3.24.18.12.6 14 12 1 8 6 4 2 Voltage (V) Power Density (W/cm 2 ) Peak Current / Ic Peak Current / Ic 5 6 4.5 4 5 3.5 3.6x Ic 4 3 2.5 3 2 2 1.5 1 1 s Pulses 1.5 1 2 3 12 # of Pulses 45 1 8 6 4 2 9.1x Ic 3 ms Pulses 1 2 3 4 5 6 7 8 9 1 11 12 # of Pulses Ic (A) Measurements by Jankowski & Iwasa, MIT 4 35 3 25 2 15 1 5 Ic (A)
Conductor with surround stabilizer has been found to exhibit superior dielectric strength Testing compared the dielectric breakdown of the two types in a winding geometry. Nylon former cloth insulation Slit then Cu stabilizer Voltage rounded edges Sharp edges cloth insulation Cu stabilizer then slit Vacuum impregnated Stycast W19 Probability of breakdown 1.9.8.7.6.5.4.3.2.1 as-slit Cu surround (2 mm) as-slit or copper surround YBCO tapes Nylon former as-slit or copper surround YBCO tapes 1 1 1 1 Breakdown Strength [kv/mm] Sample Average breakdown voltage 1% probability breakdown 26 Applied Superconductivity Conference Seattle, WA As-slit 29.4 kv/mm 1 kv/mm 8 Slit & surround stabilizer 84.9 kv/mm 19 kv/mm Data from R. Duckworth
Ic/Ic(original) 4 mm wide, Cu stabilized conductor shows excellent irreversible axial strain and yield strength* 15% 1% 95% 9% 85% 8% Ag overlayer only ε irr Single-side Cu (3 microns) Surround Cu (15 microns).4%.1.2.3.4.5.6.7 Tensile Strain (%).48%.54% Wire design Bare Metal Sub. 2G w/ Ag overlayer only 2G w/ surround Cu 15 μm) Yield Stress (MPa) at.2% 455 (295K) 69 (76K) 455 (295K) 693 (76K) 454 (295K) 64 (76K) Axial-strain performance of the prototype practical conductor comfortably meet the most severe benchmarks for applications NIST. Yield strength is much higher than that of other 2G conductors 26 Applied Superconductivity Conference Seattle, WA 9 *Data from Ekin & Chaggour, NIST
4 mm wide, Cu stabilized conductor shows superior bend & tensile properties Ic/Ic(original) 1% 9% 8% 7% 6% Bend&Hold S i 3 Compressive -11-12 -14-17 -2-25 -37 51 33 22 18 26 Applied Superconductivity Conference Seattle, WA Bend diameter (mm) Bend & Release Tensile 95% 95 % Ic retention when bent : Tension - 25 mm diameter both Bend & Hold and Bend & Release Compression < 11 mm diameter - Bend & Release ~16 mm diameter - Bend and Hold 1 Critical Current (A) 6 45 3 15 Tensile stress applied at room temperature 4 mm wide, Surround Cu stabilizer 1 2 3 4 Stress (MPa) Critical Tensile Stress of IBADbased conductor > 35 MPa Critical Tensile Stress of 1-G conductor = 15 MPa Nickel superalloy (IBAD)-based conductors are > twice as more robust than 1G *AMSC presentation, DOE Peer review 23
4 mm wide, Cu stabilized conductor readily passes hermetic test with no change in Ic or thickness 8 16 Ic (A) Surround Cu stabilizer 6 4 2 Original Ic Ic after hermetic test Original Thickness Thicness Thickness after hermetic test Thickness change : 152 ±1.5 μm 153 ±1.1 μm 1 2 3 4 5 6 7 8 Position (cm) 12 8 4 Thickness ( μm) Surround Stabilizer conductor structure completely encapsulates HTS & protects it from environment 26 Applied Superconductivity Conference Seattle, WA 11
Deliveries of slit & surround stabilized 2G conductor being made for the Albany Cable Project June 24: 61 m, 4 mm wide, surround copper stabilized, 1 micron substrates (IBAD YSZ), average Ic = 122 A/cm delivered to SEI First 2G cable with 4 mm conductor demonstrated 1 m, 215 A cable, ac losses 5 times less than previously made 2G cable Cable core diameter is 16 mm smallest demonstrated March 25: 113 m, 4 mm wide, 1 micron substrates (IBAD YSZ), average Ic= 16 A/cm, delivered to SEI July 25: 27 m, 4 mm wide, 5 micron substrates (IBAD MgO), average Ic = 14 A/cm (spec was 1 A/cm) shipped to SEI # meters 6 5 4 3 2 1 1 to 11 11 to 12 12 to 13 13 to- 14 Total 27 m Average = 14 A/cm 14 15 to to 15 16 16 to 17 17 to 18 18 to 19 19 to 2 > 2 26 Applied Superconductivity Conference Seattle, WA 12 Ic range (A/cm) Sumitomo Electric
1 st 1-m 2G cable fabricated: Shows robustness of 4 mm 2G conductor 61 m of fully processed conductor i.e. slit to 4 mm width and plated with copper Surround Stabilizer shipped to SEI. Av. Ic of all tapes = 122 A/cm. 1 m long 2-G cable : Tapes spiral wound with HTS layers in tension Electric Field [uv/cm] 3 2.5 2 1.5 1.5 -.5 Ic = 215A at 1uV/cm criterion 5 1 15 2 25 Current [A] Total # tapes ea. 1.2 m Average Ic of tapes Average Ic # tapes Estimated Ic of cable (accounting for field) Measured Ic of cable 48 5.4 A 2421 A 214 A 215 A No degradation in Ic of cable even though the HTS layers were spiral wound in tension with a small diameter former (16 mm) 26 Applied Superconductivity Conference Seattle, WA 13 Sumitomo Electric
First demonstration of a 2G cable with acceptable ac losses for practical HTS applications A c loss [W /m ] 1 1.1.1.1 Measured Loss Metal Former No shielding layer 1 1 1 Loading Current [Arms, 6Hz] Ac loss [W/m] 1.1.1.1 FRP Former No shielding layer 1 1 1 Loading Current [Arms, 6Hz] AC loss @ I peak /I c =.67 Albany Cable SuperPower/SEI AMSC-Southwire Cable* AMSC/Southwire/ORNL.1 W/m FRP former 2 W/m.4 W/m Metal former (*AMSC presentation DOE Peer review 23) AC losses of new 2G cable is 5-2 times less than that of 2G cable previously demonstrated 26 Applied Superconductivity Conference Seattle, WA 14 Sumitomo Electric
2nd 1-m 2G cable built in 25 with complete structure including shielding layers using new conductor 1 Cable features FY4 FY5 # conductor layers # shield layers 4 4 2 Ac loss [W/m].1.1 Conductor Shield Core Total Total # 2G tapes used Cable Ic (A) AC loss in conductor + core (W/kA-m) 48 215.4 88 235 (c) 224 (s).16.1 1 1 1 Loading Current [Arms, 6Hz] AC losses in conductor + core is 2.5 times less in the new 2G cable with a complete structure (shield layers) 26 Applied Superconductivity Conference Seattle, WA 15
Benefits from switching to thinner substrate and status of the final wire delivery 26 Applied Superconductivity Conference Seattle, WA 16
Use of high-strength 5 micron substrates yielded thin-profile 2G conductors with much higher tensile strain & critical tensile stress Conductor with 1 μm substrate Conductor with 5 μm substrate Stress (MPa) 14 12 1 8 6 4 2 2G with High-strength 5μm substrate 2G with 1μm substrate 5 1 15 2 25 3 35 4 45 Strain (%) Tensile Stress (MPa) 16 12 8 4 T = 76K Bare substrates (5 μm) Batch 1 Complete conductor (5 μm) Bare substrates (1 μm) Batch 3 Batch 2 Complete Conductor (1 μm).5 1 1.5 2 Tensile Strain (%) Critical Current (A) 6 45 3 15 1 micron substrate conductor 1 1 micron substrate conductor 2 5 micron substrate conductor 1 5 micron substrate conductor 2 2 4 6 Tensile Stress at R.T. (MPa) 2G conductor made with 1 micron substrate High-strength 5 micron substrate Yield strength at 77 K* 65 MPa 12 MPa Critical tensile stress at RT 35 MPa 55 MPa 26 Applied Superconductivity *Measurements Conference Seattle, Y. WA Zhou and K. Salama (U.Houston) 17 N. Cheggour, D. Van der Laan, J. Ekin (NIST)
Ic/Ic(original) Volatge Ic retention (μv) (%) Superior bend properties in joints & splices made with thin-profile conductors with 5 micron substrates 1% 9% 8% 7% 6% 5% 4 1 35 8 3 25 6 2 4 15 1 2 5-1 Bend at R.T. and Test While held on Mandrel -11-12 -14-16 4mm wide tape w/ 1 micron substrate & 2 micron surround Cu 4 mm wide tape w/ 5 micron substrate & surround Cu Compressive -19-23 26 Applied Superconductivity Conference Seattle, WA 24 19 16 14 12 Bend diameter (mm) Splice using a 3.5 cm long piece bent on 2" mandrel Joint Bent over 1.5" mandrel Bent over 1" mandrel Original 2" 1.5" 1" Current (A/cm) Bend Diameter Minimum bend dia reduced from 22 to 11 mm 1 9 Tensile 95% 1 9 8 7 6 5 4 3 2 1 Resistivity (nω -cm 2 ) 2 4 6 8 1 12 14 16-5 Copper stabilizer YBCO substrate 18 solder First step - test single tape only. Second step- test joints & splices Joint Splice 4 mm wide conductors each with 2 μm surround copper stabilizer Joint or splice length = 3 or 3.5 cm Original tape thickness =.95 mm Thickness at joint or splice =.22 mm (~ 2 times thinner that that with 1G or other 2G!) No degradation in Ic (1 μv/cm) over the joint or splice Joint or splice resistivity = 4 to 5 nωcm 2 No degradation in Ic and resistivity when joint or splice is bent even down to 1 diameter and thermal cycled three times. Ic was tested at every thermal cycle
Significant progress in 2G scale-up in the last 4 years 8, 7, 6, 5, 4, 3, 2, 1, Critical Current * Length (A-m) 1 m 1 m to 322 m in 4 years 18 m 322 m 26 m 158 m 97 m 62 m 1, 1, 1, 1 1 Jun-2 Dec-2 Jun-3 Dec-3 Jun-4 Dec-4 Jun-5 Dec-5 Jun-6 May-2 Oct-2 Mar-3 Aug-3 Jan-4 Jun-4 Nov-4 Apr-5 Sep-5 Feb-6 Jul-6 Nov-6 Critical Current * Length (A-m) Year 26 Applied Superconductivity Conference Seattle, WA 19
2G wire is produced in 3 m lengths with high Ic & excellent uniformity 35 Min Ic = 263 A = 219 A/cm over 322 m. Uniformity of 4.3% over 322 m. Critical current (A) 3 25 2 15 1 5 World Record : 7,52 A-m! 77 K, Ic measured every meter over entire tape width of 12 mm 5 1 15 2 25 3 Position (m) 26 Applied Superconductivity Conference Seattle, WA 2
We are now routinely processing MOCVD tapes in lengths over 3 m 14 12 # tapes 1 8 6 4 2 May onwards 5-1 1-2 2-3 3-4 4-5 5-6 MOCVD Process length (m) 35% of tape produced by MOCVD are 2+m. 71% of tape produced since May are 2+ m and 43% are 3+ m 31 production runs yielding 5,72 m of 12 mm wide tape (= 17,16 m of 4 mm wide tape) 26 Applied Superconductivity Conference Seattle, WA 21
2G conductor is now available in long lengths with Ic in the realm of 1G & Je about 2x better than 1G End-to-end critical current of 4 mm wide 2G conductor slit from 12 mm wide tape 14 End-to-end Ic = 1 A over 27 m @.4 μv/cm 12 Critical current (A) 1 8 6 4 2 Position (m) Ic = 1 A in a 4 mm wide 2G conductor over 27 m! Je = 26.3 ka/cm 2 (for a 2 micron surround stabilizer i.e. 4 micron total) compared to a 1G Je of 13 ka/cm 2 to 17 ka/cm 2 26 Applied Superconductivity Conference Seattle, WA 1 21 41 61 81 11 121 141 161 181 21 221 22 241 261
Critical currents of 2 to 25 A/cm reproducibly achieved in long lengths from May onwards 3 25 Average Ic (A/cm) 2 15 1 5 263 264 265 266 269 27 271 272 273 274 276 277 28a 28b MOCVD Run # #267 was damaged after MOCVD. #268 & # 275 were experimental runs Runs #278 & #279 were interrupted. 26 Applied Superconductivity Conference Seattle, WA 23
More than 12, m of qualified tape in inventory for Albany Cable project Piece length required = 42.4 m 5% of tapes > 1 m piece length ~ 3% of tapes > 2 m piece length 35 3 25 # tapes 2 15 1 5 45-1 1-15 15-2 2-25 25-3 3-35 35-4 Tape length range (m) 26 Applied Superconductivity Conference Seattle, WA 24
Thank You 26 Applied Superconductivity Conference Seattle, WA 25