High Field HTS SMES Coil

High Field HTS SMES Coil R. Gupta, M. Anerella, P. Joshi, J. Higgins, S. Lakshmi, W. Sampson, J. Schmalzle, P. Wanderer Brookhaven National Laboratory, NY, USA December 1, 2014 High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 1

From our sponsor: Overview ARPA-E s mission is to catalyze and accelerate the creation of transformational energy technologies by making high-risk, high-reward investments in their early stages of development This presentation summarizes an aggressive R&D where We demonstrated a higher field and a higher operating temperature energy storage coil than proposed before 12.5 T SMES coil operating at 27 K High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 2

SMES SYSTEM Proposal Magnet Energy Storage System with Direct Power Electronics Interface Project Goal: Competitive, fast response, grid-scale MWh superconducting magnet energy storage (SMES) system Team member major contributions: ABB: Power electronics, Lead BNL: SMES coil and switch SP: 2G HTS manufacture and improved production UH: Wire manufacturing process research High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 3

Focus of the Presentation Technology for High field HTS SMES coil Design, construction and test results For economic viability of a large scale energy storage system, cost of coated conductor must come down significantly (smart designs can help) The technology developed could already be applied to special purpose storage system and other applications High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 4

SMES Options with HTS High Temperature Option (~65 K): Saves on cryogenics (Field ~2.5 T) High Field (~25 T) Option: Saves on Conductor (Temperature ~4 K) Previous attempts: LTS: up to ~5 T HTS: few Tesla (high temp. to save on cryo) High Temperature SMES Ring Our analysis on HTS option: Presently conductor cost dominates the cryogenic cost by an order of magnitude High Field SMES Ring High field HTS could be game changer: Very high fields: 25-30 T (E α B 2 ) Only with HTS (high risk, high reward) Also: A medium field and medium temperature option (a new record 12.5T@27K demonstrated, thanks to arpa-e) High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 5

The Basic Demo Module Aggressive parameters: Field: 25 T@4 K (more than ever) Bore: 100 mm (large) Hoop Stresses: 400 MPa (>2X) Conductor: ReBCO (evolving) High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 6

Conductor ReBCO Tape HTS tape: angular dependence Measurements at NHMFL (earlier sample) SMES specs (12 mm): >700 A@4K (at any angle) 12 mm wide ReBCO tape with high strength hastelloy substrate High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 7

Large Scale SMES Concept (1) A torus would consist of a large number of solenoid module Field becomes parallel => less amount of conductor required High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 8

IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), April 2015. Radius: 5 meter, height ~5 meter Consists of double pancakes same as in demo Large Scale SMES Concept (2) 10 rings, each consisting of ~1000 double pancakes GJ scale GRID storage system that can fit in a room! Moreover, a small B (<0.5 T) for a large B// (30 T) means a major reduction in conductor cost (~1/5 with an optimized HTS) High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 9

Design Parameters of BNL Demonstration Coil Stored Energy 1.7 MJ Currrent 700 Amperes Inductance 7 Henry Maximum Field 25 Tesla Operating Temperature 4.2 Kelvin Overall Ramp Rate 1.2 Amp/sec Number of Inner Pancakes 28 Number of Outer Pancakes 18 Total Number of Pancakes 46 Inner dia of Inner Pancake 102 mm Outer dia of Inner Pancake 194 mm Inner dia of Outer Pancake 223 mm Outer dia of Outer Pancake 303 mm Intermediate Support 13 mm Outer Support 7 mm Width of Double Pancake 26 mm High field and big radius create large stresses (~400 MPa) High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 10

Cross-section of Coil and Support Tube Conductor used (ReBCO from SP): Well over 6 km (12 mm wide tape) High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 11

Grading to Optimize Magnetic and Mechanical Design Current density J (A/mm 2 ) Intermediate end structure Number of turns per pancake (for same coil i.d. and o.d.) Current density J (A/mm 2 ) 215 270 182 208 220 258 Adjusted for grading: Cu thickness in HTS tape (65 and 100 mm) SS tape thickness (65 and 100 mm) (more copper in ends; more SS in center) axial radial (Max 7.6 T) B r B r (Max 7.1T) End Result: Improved performance Better mechanical structure and reduced Bperp Initial 1.7 MJ Design Optimized 1.7 MJ Design High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 12

HTS Single Pancake High strength HTS tape, co-wound with SS tape (for insulation and added strength) Thickness of SS tape and copper on HTS adjusted to optimize the performance V-taps for QA Outer: ~210 meter 12 mm tape (258 turns) High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 13

Two Pancakes Connected with Spiral Splice Joint High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 14

Inner and Outer Coils Assembled Inner Coil (102 mm id, 194 mm od) 28 pancakes Outer Coil (223 mm id, 303 mm od) 18 pancakes Total: 46 pancakes High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 15

Coils, Test Fixtures and Support Structure Pancake coils: inner and outer Outer Support Tube for Inner Outer Assembly Tube for Outer 11 T, 760 A coil and fixture 77 K Test Fixture for outer Inner Assembly Tube for Inner Copper Discs Outer Support Tube for Outer High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 16

Inner and Outer Coils Inner (in support tube) Outer (prior to support tube) High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 17

Final Assembly Outer inserted over inner coil SMES coil in iron laminations High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 18

Test Results High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 19

77 K Test of a Series of Double Pancakes (inner) Critical current (1 µv/cm) Two single pancakes powered in series. High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 20

I c (A) based on 0.1mV/cm criterion 250 Outer double pancake coils 225 200 175 150 125 100 75 50 25 0 O1-1 O1-2 O2-1 O2-2 MT23, Lakshmi, et al O9-1 77 K Test of a Series of Double Pancakes (outer) Two pancakes powered in series Four types to achieve grading (see slide 12) O9-2 O3-1 n-value Type A -CC(160 mm) + SS (25 mm) Measured value, Beyond range Type B -CC(160 mm) + SS (50 mm) Measured value, Beyond range Type C -CC(120 mm) + SS (25 mm) Measured value, Beyond range Type D -CC(120 mm) + SS (50 mm) Measured value, Beyond range O3-2 O4-1 O4-2 O7-1 O7-2 Single pancake coil ID High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 21 O8-1 O8-2 O5-1 O5-2 O6-1 O6-2 I c (A), n-value 200 150 100 50 0 O1-1 Single pancakes powered alone 1 mv/cm 0.1 mv/cm, Type A, Type B, Type C, Type D n- value O1-2 O2-1 O2-2 O9-1 O9-2 O3-1 O3-2 O4-1 O4-2 O8-1 O8-2 Outer single pancake coil ID Higher I c in coil at 77K, however, doesn t necessarily translate in to a higher I c at 4K (present conductor) O5-1 O5-2 O6-1 O6-2

2 pancakes with similar critical currents Double Pancake 77 K Test 2 pancakes with very different critical current one pancake good and other pancake defective Note: Thorough 77 K test of each pancake was an important part of a series for QA High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 22

IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), April 2015. 12 pancakes 760 A, 4K, 11.4 T 46 pancakes 350 A, 27K, 12.5 T Peak fields higher 2 pancakes 1140 A, 4K HTS SMES Coil High Field Tests High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 23

1200 Double Pancake Coil Test Nominal design current: ~700 A I c (A) @0.1mV/cm 1000 800 600 400 200 0 Top Coil Bottom Coil 0 10 20 30 40 50 60 70 80 Temperature (K) Ramp rate up to 10 A/s The option of operating over a large range (the benefit of HTS) High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 24

12 Pancake Coil Test Current (A) Charge 800 750 700 650 600 550 500 450 400 350 300 250 200 150 100 50 0 4:09:07 PM 4:14:53 PM 4:20:38 PM 4:26:24 PM 4:32:10 PM 4:37:55 PM 4:43:41 PM 4:49:26 PM Time 11.4 T in 100 mm bore Current (A) Quench 800 700 600 500 400 300 200 100 0 0 1 2 3 4 5 Time (sec) Energy (~125 kj) extracted and dumped in the external resistor. 77 K re-test (after quench) showed that the coil remained healthy. High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 25

Preparation for the Final Test High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 26

Current (A) 400 350 300 250 200 150 100 50 350 Amp 425 kj id:102 mm od:303 mm SMES Coil Run on 5/21/14 12.5 Tesla at 27 K Coil Current Record field/energy density in a superconducting magnet at a temperature of 10 Kelvin or higher 0 14:24 15:36 16:48 18:00 19:12 20:24 21:36 Time (hh:mm) 27 K possible with liquid Neon High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 27

Status of ARPA-E SMES Coil The design goal was: 1.7 MJ at ~700 A with 25 T at 4 K. We tested the unit at several temperatures between 20-80 K, including the 350 Amp (12.5 T) test at 27 K. During one such test, the system tripped due to a data entry error at ~165 A well below the earlier magnet test current. This trip resulted in damage to a few current leads in the inner coil. It appears that there was arcing, perhaps during shut-off. Since the test was not limited by the field performance, the SMES coil still has the potential to reach higher field after repair. High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 28

Quench Protection High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 29

BNL HTS Quench Protection Strategy A multi-pronged strategy developed and used at BNL in various HTS programs: Detect early and react fast with an advance quench protection system 1. Developed an advanced low-noise electronics and noise cancellation scheme to detect pre-quench voltage (phase) where HTS coils can operate safely 2. Fast energy extraction with electronics to handle high isolation voltage (>1kV) 3. Use inductively coupled copper discs for fast energy extraction Drawback: additional energy loss during charging and discharging Current (A) High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 30 Voltage (mv) Twelve coil test at 4K (~12 T, ~120 KJ) 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0-0.2 Difference Voltage between Coil#2 and Coil#11 (1mV = 0.1 mv/cm for 100 m), with offset Pre-quench phase 745 750 755 760

800 Copper Discs for Energy Extraction Inductively coupled cooper discs between two double pancakes I 2 (Amp 2 ) 6.E+05 5.E+05 4.E+05 3.E+05 700 2.E+05 1.E+05 Current (A) 600 500 400 300 200 100 0 This fast extraction provides initial margin at the critical time 0 1 2 3 4 5 Time (sec) High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 31 I 2 (Amp 2 ) 0.E+00 6.E+05 5.E+05 4.E+05 3.E+05 2.E+05 1.E+05 0 1 2 3 4 5 Time (sec) Most action in milliseconds 0.E+00 2.5 2.502 2.504 2.506 2.508 Time (sec)

SUMMARY Even though we didn t reach the aggressive design goal of 25 T, in a big aperture (~100 mm) superconducting magnet with large hoop stresses (~400 MPa) in the first attempt, we did learn several things in the process beside creating new records. This provided a significant experience in using a large amount of coated conductor (over 6 km of 12 mm wide tape) in a demanding 4K, high field and a high stress application. Demonstration of a 12.5 T SMES coil at 27 K is a promising application of the coated conductor. The earlier most ambitious proposal was for 11 T at 20 K by Chubu Electric and Furukawa. The experience and technologies developed should also be useful in other applications, such as in NMR, ADMX, accelerators, etc. High Field HTS SMES Coil R. Gupta,..., BNL CCA2014 S. Korea Dec. 1, 2014 32