Transcript
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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
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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
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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
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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
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2
3
F1
20 kA-rms, 0.25 s 56.8 kA-peak
9 3
11
3
5
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Relay Relay ## 11 22 33 55
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.
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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 – – – –
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OL3, TVO’s Olkiluoto – – – –
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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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