Superconducting cables Development status at Ultera

Transcription

1 1 Superconducting cables Development status at Ultera "Superconductors and their Industrial Applications Pori, Nov 2006 Chresten Træholt (D. Willén) Senior Development Engineer, Ultera A Southwire / nkt cables Joint Venture

2 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 3 8 years of operation experience 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 Copenhagen, Denmark 30 m x 2.0 ka x 30 kv 104 MW 2 years operation 12,000 h at 100% load

4 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

5 200 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.

6 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

7 Fault current / protection at Bixby 13.2 kv kv 13.2 kv SPR Inst. OC ka-rms, 0.25 s 56.8 ka-peak HTS Cable F Bus B Inst. OC Ω N.C. Relay # Protection Zone 1 Transformer 2 HTS Cable 3 13 kv Bus B 5 13 kv Bus A Bus A F2 3 ~20 ka-rms ~56.8 ka-peak 5 F3 F4 10 ka-rms 28.4 ka-peak

8 Bixby Rd. station layout 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

9 AEP Site Layout 9 Triaxial HTS above ground cable section Termination Manhole with splice Triaxial HTS underground cable section Liquid Nitrogen Return Termination

10 HTS Cable installation 10 6 Feb 2006

11 Cryostat Installation 11

12 HTS cable installation 12 7 Feb 2006

13 Cable Installation 13

14 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.

15 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.

16 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

17 HTS-4 Skid: 1 kw Pulse Tube 17

18 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 73 K ¼ Atm 65 K Gas OUT LN to 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).

19 DC Current Testing to 6 ka 19

20 Offline Voltage Tests VLF per IEEE kv, 0.1 Hz, 30 minutes + voltage soaked 24 h

21 Energized August 8, kv, 3000 A, 200 meters 21

22 Cable In Service 8/8/ Amps, 55 MW 22 AEP-Bixby HTS Cable - Power On 8 August Amps Temperture P1 P2 P3 N TI102 TI104 TI105 TI :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

23 Bixby Rd. view 10/11/ Amps 23

24 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

25 How are HTS cables different? 25 Higher transmission capacity ( ka) Lower impedance Lighter, longer unit lengths No EMF emissions No thermal impact on soil New network component with new opportunities

26 26 1. Connect windpower to the grid One voltage level (MV, e.g. 30 kv) MW High current ( ka) AC or DC m long units Light-weight No magnetic fields 30 kv conv. 30 kv HTS

27 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 kv to 400 kv, GW Monitoring & maintenance Comparison 20 Cu busbars, 50 m <10 superlinks, >100 m

28 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 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

30 Thank You! 30