HTS Distribution Cable with Intrinsic FCL Capacity
HTS Triax® FCL Cable
Dag Willén, nkt cables group a/s
SuperNet, Delft, 11 Nov 2015
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Acknowledgements
Ultera® – A Southwire / nkt cables Joint Venture
The Hydra Project
• J. Yuan, J. Maguire, D. Folts, N. Henderson, American
Superconductor
• D. Knoll, Jerry Tolbert, Southwire, Carsten Thidemann, Heidi
Lentge, nkt cables
• M. Gouge, R. Duckworth, J. Demko, ORNL
• Z. Wolff ,Consolidated Edison
This material is based upon work supported by the Department of
Homeland Security, Science & Technology Directorate, under
contract #HSHQDC-08-9-00001.
Joining forces to develop and manufacture the Resilient Electric Grid
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Operation experience of HTS cables
A total of 14 years of operation
Installations
Copenhagen, Denmark
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30 meter, 30 kV, 104 MW
2 years operation 2001 – 2003
Supplied 50,000 users
Carrollton, GA
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30 meter, 12.5 kV, 27 MW
6 years operation 2000 – 2006
Supplied energy to Southwire’s
cable factories
Columbus, OH
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200 meter, 13 kV, 69 MW
6 years operation Aug 2006 – Oct 2012
Carried 100% of substation load
New York, NY
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~200 meter, 13 kV, 4kA  96 MW
Qualification test compete
Installation 2016
Substation MV Bus Tie
We have a long experience of operating HTS cable systems
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Lowest AC loss
In collaboration with Alliander and TU Delft
Cable design
• Round conductor, Ø42 mm
• Pitch angles
• Gaps
• 0.11 W/m at 3.0 kArms. 60 Hz
It is possible to make very low-loss AC conductors with 2G HTS
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Efficient Cryostat
In-house development
50 m demonstrator
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Optimal MLI arrangement
Vacuum 10-5-10-6 mbar
Warm and cold getters
Low-loss spacers
P=0.5 W/m in a 100/143 mm cryostat
Low loss and low flow friction in a compact thermally insulating duct
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First FCL cable tests
3 m cable in open bath
Test parameters
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Voltage 32 Vpk
Available fault current 60 kArms
Limited fault current 30-45 kApk
140 ms fault
DT ~13 K (77 → 90 K)
No degradation
• 7.5 kVrms/km
• Immediate limitation in first-cycle front edge
• Ifcl = 21 kArms
The HTS wires survive the rapid heating to Tc
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Application of FCL cable: Substation Intertie
Project Hydra, New York, NY
HTS Triax with Fault Current Limiting Capability
• 13.8kV
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4,000 A ● 96 MVA
• Rated 40kA for 67ms
• Limit Fault Current by 17% in 3 cycles
• HTS Triax® Technology
Increases System Reliability and Resiliency
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Type test of FCL cables
Completed at ORNL in 2011
25m HTS Triax® Cable
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Full Scale Terminations
DC critical current test
AC loss: 1PH & 3PH
3PH AC current up to 4kA
(thermal stability for cable & terms)
PD measurements at test voltage
AC withstand up to 39 kV
Impulse Withstand: 110kV BIL
Fault current test up to 40+kArms (unlimited)
15 kV HTS Triax® FCL Cable qualified for installation in distribution grids
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FCL Performance
25 m HTS Triax® FCL Cable Type Test
Results
Unlimited current 46 kArms (65 kApk)
Limited current 25 kArms (35 kApk)
Limitation within first-cycle front edge
No degradation
Minimal overall temperature increase
Measured versus Simulated Results
Symmetrical Fault
25-m Cable Ic
Measured Limited Current (kA)
Meas Unlimited Current
Simulated Limited Current (kA)
80
9000
8500
70
8000
Critical Current (A)
60
7500
50
Phase 1
7000
Phase 2
Measured & Simulated
Limited Current
Phase 3
40
6500
6000
30
5500
5000
73
74
75
76
Temperature (K)
77
78
79
Current (kA)
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20
10
0
-10
-20
-30
-40
-50
-60
-70
Normal Op
Fault
After fault
Unlimited Fault Current
-80
0.0000
0.0083
0.0167
0.0250
0.0333
0.0417
0.0500
0.0583
0.0667
0.0750
0.0833
0.0917
0.1000
Time (S)
Big advantage: Resistive limitation removes the asymetric fault peak
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Heating during faults
Non-limiting let-through faults (LT) and bolted faults (FC)
Example: 1600 m long 3 kA, 15 kV system
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Zero-load operation
3 kA normal operation
Stability limit, 3 kA operation
Boiling temperature
115
3 kA normal operation
10 kA LT w/o limitation
2 x LT w/o limitation (wi
20 kA limited FC
LT + FC
90
105
Tboil [K]
T(LT+FC) [K]
85
95
85
75
Tnom [K]
Margin for 3 kA operation
T(1xFC) [K]
80
T [K]
T [K]
Tmax [K]
T(2xLT) [K]
75
T(1xLT) [K]
65
T(ZL) [K]
70
Tnom [K]
55
0
500
1000
L [m]
1500
65
0
500
1000
1500
L [m]
The cable system supports one or two event with continued operation
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HTS Cable Manufacturing
Ultera®/nkt cables/Southwire HTS line in Cologne
Dedicated cleanroom for HTS cable manufacturing
1 crate HTS per layer
Drum
Capacity
22 ton
(~2 km)
HTS Fab
Finished
HTS Triax®
Cable
Conductor
Insulation
Drum with
transport cover
Existing line can produce 100 km HTS cable/yr
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Installation of HTS cables
Two-step approach: Cryostat first, then the HTS cable
Pull Cryostat
Pull HTS Cable
Joints
• 1 day/unit
• Conventional pulling
techniques
• Pull into typical duct
• PE jacket lubricated during
pulling
• 1 day/unit
• Conventional pulling
techniques
• Pull into cryostat
• Low friction material on OD
of cable
• No lubricant
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1 wk/unit
Soldered conductor joints
Taped insulation
Welded enclosure
High-quality vacuum
Termination
• 2 wks/unit
• Protective tent
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Operation of HTS cables
Cool-down, regular inspections, service of coolers
PH1
PH2
Neut
PH3
Utility
Connections
Utility
Connections
System overview
Neut
Back-up
LN
PH3
CA
HTS Triax
Termination
PH2
BL
E-IN
-C R
PH1
YO
STA
LN Return
Supply
LN
Refrigerator
T
HTS Triax
Termination
Cooling System
Service requirement similar to fluid-filled cables and HV transformers
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Future applications
Cost-driven acceptance
Distribution
Transmission, transport
• First applications possible now
• Partial undergrounding
• Parallel lines
• Long-distance transmission
• More widespread use ↔ reduced volume and cost
• Resilience and environment
Long-term
• Electric ships and avionics
• Defence
• Levitating ground transport and energy storage
We are still on a steep development curve of performance and cost
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Thank you for your attention!
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