1 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
AEP Project Partners 2 Partner Southwire/nktc/Ultera AEP DOE Area of Responsibility/Expertise Cable design, manufacturing, termination design, installation, cryo system design, systems integration, O&M, project management 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
3 8 years of operation experience 2000 - present 2001-2003 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 Copenhagen, Denmark 30 m x 2.0 ka x 30 kv 104 MW 2 years operation 12,000 h at 100% load
4 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
200 m Triax Cable 5 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.
Type testing of the HTS Triax cable 6 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
Fault current / protection at Bixby 13.2 kv 7 138 kv 13.2 kv 1 112 SPR Inst. OC 2 2 4 4 1 1 20 ka-rms, 0.25 s 56.8 ka-peak HTS Cable F1 14 3 2 3 9 Bus B Inst. OC 12 11 0.4 Ω 3 3 5 8 N.C. Relay # Protection Zone 1 Transformer 2 HTS Cable 3 13 kv Bus B 5 13 kv Bus A 5 7 3 Bus A F2 3 ~20 ka-rms ~56.8 ka-peak 5 F3 F4 10 ka-rms 28.4 ka-peak
Bixby Rd. station layout 8 345 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
AEP Site Layout 9 Triaxial HTS above ground cable section Termination Manhole with splice Triaxial HTS underground cable section Liquid Nitrogen Return Termination
HTS Cable installation 10 6 Feb 2006
Cryostat Installation 11
HTS cable installation 12 7 Feb 2006
Cable Installation 13
Splice 14 - 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.
Terminations 15 3 Phase Connections Neutral Connection - Provides transition from superconducting materials to copper materials. - Thermal transition from 200 C to ambient temperature - 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.
HTS Cable Demonstration Cryogenic System Overview Integration 16 LN 2 Tank GN 2 Open Loop Refrigeration Backup LN 2 Cable Backup LN tank will keep cable at operating temp & pressure during system outage for predefined time duration. (AEP = 6 hrs.) Pulse Tube 1 Pulse Tube 2
HTS-4 Skid: 1 kw Pulse Tube 17
Cryogenic System 18 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. Liquid IN LN from cable @ 73 K GN @ ¼ Atm LN @ 65 K Gas OUT LN to cable @ 70 K 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. 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. Heat Exchanger ** Same laws of physics that makes water boil at lower temperature at high elevation (mountains).
DC Current Testing to 6 ka 19
Offline Voltage Tests VLF per IEEE 400.2 20 20 kv, 0.1 Hz, 30 minutes + voltage soaked 24 h
Energized August 8, 2006 13.2 kv, 3000 A, 200 meters 21
Cable In Service 8/8/2006 2400 Amps, 55 MW 22 AEP-Bixby HTS Cable - Power On 8 August 2006 2600 2400-196 2200 2000-198 Amps 1800 1600 1400 1200 1000 800 600-200 -202-204 -206 Temperture P1 P2 P3 N TI102 TI104 TI105 TI106 400 200-208 0 9:09:00 10:21:30 11:34:00 12:46:30 13:59:00 15:11:30 16:24:00 17:36:30 18:49:00 20:01:30 Time -210
Bixby Rd. view 10/11/2006 1600 Amps 23
24 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
How are HTS cables different? 25 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
26 1. Connect windpower to the grid One voltage level (MV, e.g. 30 kv) 40-150 MW High current (1.3-4.2 ka) AC or DC 200-2000 m long units Light-weight No magnetic fields 30 kv conv. 30 kv HTS
2. Power plants to grid 27 Link power plants to step up transformers Reasons Economically feasible Safety issues (Ringhals) Relocation of transformer, flexibility Redundant transformer capacity OL3, TVO s Olkiluoto 2009 27 kv to 400 kv, 1.5 2 GW Monitoring & maintenance Comparison 20 Cu busbars, 50 m <10 superlinks, >100 m
28 3. Reinforcement of the grid Difficulty to site OH 420 kv underground PEX/AL/CU High connection costs Expensive phase compensation 132 kv/1320 MVA HTS Low impedance Behaves similarly to OH line Example Southern Loop on Sjælland Herslev Hejninge Stigsnaesvaerket Omoe A C Bjaeverskov Haslev Rislev Blangslev B Masnedoe Radsted Roedsand
29 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! 30