Superconducting cables – Development status at Ultera

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Superconducting cables –
Development status at Ultera
"Superconductors and their Industrial Applications”
Pori, 15-16 Nov 2006
Chresten Træholt (D. Willén)
Senior Development Engineer, Ultera – A Southwire / nkt cables Joint Venture
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AEP Project Partners
Partner
DOE
Area of Responsibility/Expertise
Southwire/nktc/Ultera
Cable design, manufacturing, termination
design, installation, cryo system design,
systems integration, O&M, project
management
AEP
Installation site engineering, site civil &
electrical construction, O&M
ORNL
Cable research, termination research, testing,
cryo design
Praxair
Cryogenics system design, construction,
operations & service
AMSC
HTS tape supplier
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8 years of operation experience
2000 - present
•
Carrollton, U.S.A
–
–
–
–
30 m x 1.25 kA x 12.5 kV
27 MW
6 years operation
40,000 h at 100% load
2001 - 2003
•
Copenhagen, Denmark
–
–
–
–
30 m x 2.0 kA x 30 kV
104 MW
2 years operation
12,000 h at 100% load
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AEP Project, Columbus, Ohio
•
Triax design
– Coax with a common screen
– No return currents -> copper
– Less superconductor tapes
and better AC performance
than Coax
– Less cold surface
•
Challenge:
– Terminations and joints
Makes MV applications of HTS
economically feasible
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200 m Triax Cable
Voltage = 13.2 kV phase-to-phase
Current = 3.0 kArms steady state
Power = 69 MVA
Three concentric phases on a single core with one
common concentric neutral conductor.
Phases are made from BSCCO superconducting
wires.
Thermal insulation provided by vacuum insulated
double-walled stainless steel pipe.
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Type testing of the HTS Triax cable
Standard type test for
15 kV-class cable:
5 m full-scale cable
with two terminations
Impulse:
10+/10- x 110 kV
Withstand:
36 kV AC
Continuous:
3.0 kArms
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Fault current / protection at Bixby 13.2 kV
13.2 kV
138 kV
HTS Cable
112
1
SPR
Inst.
OC
2
4
Bus B
1
14
3
2
4
1
0.4 Ω
Inst.
OC
12
2
3
F1
20 kA-rms, 0.25 s
56.8 kA-peak
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3
11
3
5
8
Relay
Relay ##
11
22
33
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Protection
Protection Zone
Zone
Transformer
Transformer
HTS
HTS Cable
Cable
13
kV
13 kV Bus
Bus B
B
13
13 kV
kV Bus
Bus A
A
N.C.
3
3
5
7
F2
5
Bus A
F3
~20 kA-rms
~56.8 kA-peak
F4
10 kA-rms
28.4 kA-peak
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Bixby Rd. station layout
345 kV line
13 kV, 69 MVA
HTS cable
138 kV line
New 138/13 kV
transformer
138/13 kV
transformation
13 kV radials
out to customers
The 13 kV HTS cable runs the entire distribution station
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AEP Site Layout
Triaxial HTS
above ground
cable section
Termination
Manhole
with splice
Liquid
Nitrogen
Return
Termination
Triaxial HTS
underground
cable section
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HTS Cable installation
• 6 Feb 2006
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Cryostat Installation
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HTS cable installation
• 7 Feb 2006
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Cable Installation
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Splice
- Cable to cable joint in underground man-hole.
- Joins superconducting phases at –200 C operating
temperature -> nΩ.
- Joins dielectrics and controls field stresses.
- Provides thermal insulation across joint.
- Standard size utility manhole utilized for joint.
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Terminations
3 Phase Connections
- Provides transition from
superconducting materials to
copper materials.
- Thermal transition from –200 C to
ambient temperature
Neutral Connection
- Controls electrical stresses.
- Provides input and/or output
location for LN coolant.
- Provisions made for temperature
and pressure measurements and
monitoring.
- Electrical connections to utility
made by means of industry
standard NEMA pad.
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HTS Cable Demonstration
Cryogenic System Overview Integration
GN2
LN2
Tank
Open Loop
Refrigeration
Pulse
Tube 1
Backup LN tank will keep cable
at operating temp & pressure
during system outage for
predefined time duration.
(AEP = 6 hrs.)
Backup
LN2
Cable
Pulse
Tube 2
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HTS-4 Skid: 1 kW Pulse Tube
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Cryogenic System
TM-11000: Storage tank to hold liquid nitrogen.
11,000 gallon capacity. Delivery trucks fill 1-2 times
per week.
Utility Vaporizer: Vaporizes liquid nitrogen to
provide gaseous nitrogen to operate control valves
and warm LN prior to release to atmosphere
TM-3000
Refrigeration Skid: Houses tanks, valves and
heat exchanger needed to cool cable.
Cryo Pump Duct: Liquid nitrogen circulation
pumps are located here. 2 pumps total – one in
service and one in stand-by reserve.
Vacuum Pumps: Provide suction to subcool liquid
nitrogen and remove heat from HTS cable.
TM-3000: Storage tank for backup reserve of
subcooled liquid nitrogen to provide cooling to cable
in event of skid failure or power outage that drops
the cooling system.
Liquid IN
Gas OUT
GN @ ¼ Atm
LN from cable @ 73 K
LN @ 65 K
LN to cable @ 70 K
Heat Exchanger
Cooling Method: Vacuum pumps reduce vapor
pressure in tank of liquid nitrogen. Reduced
pressure makes liquid boil at lower temperature.
LN from cable circulates through the tank and exits
at lower temperature.
** Same laws of physics that makes water boil at
lower temperature at high elevation (mountains).
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DC Current Testing to 6 kA
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Offline Voltage Tests VLF per IEEE 400.2
20 kV, 0.1 Hz, 30 minutes + voltage soaked 24 h
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Energized August 8, 2006
13.2 kV, 3000 A, 200 meters
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Cable In Service 8/8/2006
2400 Amps, 55 MW
AEP-Bixby HTS Cable - Power On
8 August 2006
2600
-196
2400
2200
-198
2000
1800
-200
P1
P2
1400
-202
1200
-204
1000
Temperture
Amps
1600
P3
N
TI102
TI104
TI105
TI106
800
-206
600
400
-208
200
0
9:09:00
-210
10:21:30
11:34:00
12:46:30
13:59:00
15:11:30
Time
16:24:00
17:36:30
18:49:00
20:01:30
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Bixby Rd. view 10/11/2006
1600 Amps
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What does this mean?
• Just like a conventional cable type, the MV Triax has
–
–
–
–
–
Gone through a development phase
Produced
Been type tested
Installed
Long-term full-scale testing (2 years) underway (Bixby)
• Then the MV triax (10-35 kV) is a commercial product
– Data sheets
• On equal footing with 420 kV PEX, submarine cables,
etc… product range
• By 2008, Ultera will have 12 yrs of operation experience
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How are HTS cables different?
• Higher transmission capacity (1.3 - 3.5 kA)
• Lower impedance
• Lighter, longer unit lengths
• No EMF emissions
• No thermal impact on soil
New network component with new opportunities
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1. Connect windpower to the grid
•
•
•
•
•
•
•
One voltage level (MV, e.g. 30 kV)
40-150 MW
High current (1.3 - 4.2 kA)
30 kV conv.
AC or DC
200-2000 m long units
Light-weight
No magnetic fields
30 kV HTS
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2. Power plants to grid
•
•
Link power plants to step up transformers
Reasons
–
–
–
–
•
OL3, TVO’s Olkiluoto
–
–
–
–
•
Economically feasible
Safety issues (Ringhals)
Relocation of transformer, flexibility
Redundant transformer capacity
2009
27 kV to 400 kV,
1.5 – 2 GW
Monitoring & maintenance
Comparison
– 20 Cu busbars, 50 m
– <10 superlinks, >100 m
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3. Reinforcement of the grid
• Difficulty to site OH
• 420 kV underground PEX/AL/CU
– High connection costs
– Expensive phase compensation
Herslev
Hejninge
Bjaeverskov
A
Haslev
Rislev
Stigsnaesvaerket
• 132 kV/1320 MVA HTS
Blangslev
B
Omoe
– Low impedance
– Behaves similarly to OH line
Masnedoe
Radsted
• Example
C
– Southern Loop on Sjælland
Roedsand
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Conclusion
• Ready to deliver MV Triax cables on commercial terms
– Unit length of 1-2 km
– Environmental benefits
– Surveillance, cooler lease and service agreements
• There are issues in industry that can be adressed by
HTS cables
– Large currents/low voltages
• Simplified grids
• Flexibility with transformer location
• Removing complete voltage levels
– Reinforcing the grid and increasing reliability
Thank You!
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