J. Kolonko, D. Larson, R. Scanlan, R. Weggel and E. Willen ... · Design, Construction and Test of HTS/LTS Hybrid Dipole, R. Gupta,… MT25, Amsterdam, 8/31, 2017 Background •To

Design, Construction and Test of HTS/LTS Hybrid Dipole, R. Gupta,… MT25, Amsterdam, 8/31, 2017

R. Gupta, M. Anerella, J. Cozzolino, P. Joshi, W. Sampson, P. Wanderer (BNL)

J. Kolonko, D. Larson, R. Scanlan, R. Weggel and E. Willen (PBL)

August 31, 2017


Background

• To achieve very high operating dipole fields (20T or above),

development of HTS/LTS technology is a must

Use expensive HTS in regions where field is very high

and relatively less expensive LTS (Nb3Sn and/or NbTi)

where field is moderate

• Whereas HTS/LTS hybrid solenoids have been built and

tested, no significant field hybrid dipoles have been

• This presentation shares the initial test experience

2


Overview

• HTS/LTS Hybrid Dipole Design and Construction

• Quench Tests

Several HTS coil quenches in hybrid dipole

NO degradation in performance observed

• Magnetization studies of HTS coils

By themselves and in hybrid dipole structure

3


Unique BNL Common Coil Dipole

Common coil 2-in-1 dipole design with simple

racetrack coils that are common to both apertures

Structure specifically designed to provide a large

open space (31 mm wide, 338 mm high)

New racetrack coils can be inserted in the magnet

without requiring any disassembly or reassembly

New insert coils become an integral part of the

magnet. Coil tests become magnet tests

Rapid-turn-around, lower cost approach allowed

hybrid dipole in DOE/SBIR program (2 years, 1M$)

Empty

space

Design, Construction and Test of HTS/LTS Hybrid Dipole, R. Gupta,… MT25, Amsterdam, 8/31, 2017 5

Insert coils in

Empty space

Design Assembly of a

pair of insert

coils

HTS/LTS Hybrid Dipole Structure

HTS coils get pushed

inside the LTS coils


HTS Coil Winding (two coils wound)

Two coils used ~300 meters of 4 mm equivalent

Conductor:

• 12 mm ASC tape

Insulation:

• Nomex


HTS/LTS Hybrid Dipole

Quench Test Results


Challenges with the HTS/LTS Hybrid Dipole

• Large coupling between HTS/LTS coils

Maximum current in HTS: ~800 A

Maximum current in Nb3Sn: ~10 kA

• Protection of the HTS coils at 4 K

• Quench protection of HTS coils in

HTS/LTS hybrid configuration

Questions:

• Can HTS coil survive quenches

without significant degradation?

• Can HTS coils be operated like LTS

Piyush Joshi:

This conference


0

200

400

600

800

1000

0.0 2.0 4.0 6.0 8.0 10.0

HT

S C

oil

Cu

rren

t (A

)

Hybrid Dipole Field (T)

Operation of HTS/LTS Hybrid Dipole

Encouraging Results:

HTS coils were ramped to

quench, just like LTS coils

No degradation in HTS

coils despite a number of

quenches

Significant demonstration.

8.7 T may be the highest

field HTS/LTS hybrid

dipole magnet

Performance limited by the leads (not by coils)

~14 T possible with new HTS tapes, in favorable direction


-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5-0

.2004

-0.1

962

-0.1

92

-0.1

878

-0.1

836

-0.1

794

-0.1

752

-0.1

71

-0.1

668

-0.1

626

-0.1

584

-0.1

542

-0.1

5

-0.1

458

-0.1

416

-0.1

374

-0.1

332

-0.1

29

-0.1

248

-0.1

206

-0.1

164

-0.1

122

-0.1

08

-0.1

038

-0.0

996

-0.0

954

-0.0

912

-0.0

87

-0.0

828

-0.0

786

-0.0

744

-0.0

702

-0.0

66

-0.0

618

-0.0

576

-0.0

534

-0.0

492

-0.0

45

-0.0

408

-0.0

366

-0.0

324

-0.0

282

-0.0

24

-0.0

198

-0.0

156

-0.0

114

-0.0

072

-0.0

03

Coil A Voltage (V)

Coil B Voltage (V)

Coil

Volt

ag

e (V

)HTS coils operated like LTS coils

Significant voltage in HTS coils: >0.2 Volts


Retest of Nb3Sn Common Coil Dipole After a DecadeC

urr

en

t (A

)

~9.5T@10kA

• Short Sample: 10.8 kA (reached during 2006 test)

• Retest: No quench to 10 kA (>92% of short sample)

Worked well when cold

tested after a decade

Was a display piece of

Nb3Sn “React & Wind”

technology for dipole


Magnetization studies in magnets

made with the HTS tapes

(Hall probe measurements)


Coil and Magnet Cross-section for Measurements

Square cross-section was chosen so that two coils can be

placed in two configurations (a) with field more parallel or

More

Parallel

More

Perpendicular

(b) more perpendicular to the wide face of the HTS tape


77 K Measurements of the HTS Coils in Various Configurations


25 A

50 A

75 A

100 A

125 A

150 A

175 A

200 A

15

Test Sequence of HTS Coils at 77 K

0 25 0 50 0 75 0, …

Gap ~12 mm


Trapped Field in HTS Coil after Previous Excitation(measured field at zero current in HTS coil, 77 K)


Two Successive Runs to 200 Amp (77 K)

Gap ~3 mm

0 200 0 200 0


4 K Measurements


Test Run at 4 K (in 2 T background field from Nb3Sn coils)

Additional field from the HTS coils in up and down ramp

(offset to start from zero to start up-ramp)


Decay of Trapped Field(after the final run to ~8.7 T hybrid field @ 4 K)

Flux creep


Summary

Encouraging Test Results of HTS/LTS Hybrid Dipole

Many LTS type quenches in HTS coils with no degradation

A robust rapid-turn-around, low-cost test facility

Insert coils become an integral part of the magnet

A variety of magnetization studies in HTS tape dipole

a) at 77 K

b) at 4 K, including in HTS/LTS hybrid dipole structure


Extra Slides


HTS/LTS Hybrid Operation and Quench Protection

• HTS & LTS powered separately

• Common quench platform; fast

energy extraction from both coils

• Quench detection response time:

< 5 msec

• Coil current interruption: < 10

micro-second after detection

• HTS coil shut-off: a few msec

• High power IGBT switches

• Electronic threshold for quench

detection: ~100 micro-volts

• HTS Quench threshold : 5 mV

• Actual test conditions (more

brutal): ~200 mV (like LTS)

Piyush Joshi:

This conference


HTS and LTS Currents (just before and after the quench)

0

100

200

300

400

500

600

700

800

-0.0

104

-0.0

094

-0.0

084

-0.0

074

-0.0

064

-0.0

054

-0.0

044

-0.0

034

-0.0

024

-0.0

014

-0.0

004

0.0

00

6

0.0

01

6

0.0

02

6

0.0

03

6

0.0

04

6

0.0

05

6

0.0

06

6

0.0

07

6

0.0

08

6

0.0

09

6

HTS Current (A)

0

1000

2000

3000

4000

5000

6000

7000

-0.0

204

0.0

05

50.0

31

40.0

57

30.0

83

20.1

09

10.1

35

0.1

60

90.1

86

80.2

12

70.2

38

60.2

64

50.2

90

40.3

16

30.3

42

20.3

68

10.3

94

0.4

19

90.4

45

80.4

71

70.4

97

60.5

23

50.5

49

40.5

75

3

Separate power supplies and separate energy extraction for HTS and LTS coils

HTS and LTS coils have different inductances and different characteristics

LTS Common Coil Current (A)


Two Successive Runs to 200 Amp (77 K)

0 200 0 200 0

Looks more dramatic

on Transfer Function

Documents

J. Kolonko, D. Larson, R. Scanlan, R. Weggel and E. Willen ... · Design, Construction and Test of HTS/LTS Hybrid Dipole, R. Gupta,… MT25, Amsterdam, 8/31, 2017 Background •To