Superconducting Cable Systems for Urban Areas AmpaCity Project - Germany Frank Schmidt Frank.Schmidt@Nexans.com 2016 IEEE PES General Meeting
Agenda Project overview Motivation for HTS cables Components of the system Operation experience Conclusions
AmpaCity Installation in Essen, Germany Technical specification - 1 km distance between substations - 10 kv system voltage - 2.3 ka operating current () Substation Herkules Cable Joint Substation Dellbrügge System in continuous operation since March 10 th, 2014 Luftbild: "Darstellung aus HK Luftbilder / Karten Lizenz Nr. 197 / 2012 mit Genehmigung vom Amt für Geoinformation, Vermessung und Kataster der Stadt Essen vom 13.02.2012"
Advantages of HTS Cable Technology Increased power density through application of HTS cables Avoiding higher voltage levels for power transmission and distribution Negligible thermal impact on the environment No drying out of soil, no thermal backfill required No maximum laying depth, no bottlenecks at cable crossings No outer magnetic field during normal operation Reduced space for substations and for cable installation Simplified cable installation, less civil works Space-savings in urban areas Increased operating safety due to fault current limitation
Motivation for AmpaCity Project Substation in suburban area HV Substation in suburban area HV Conventional HV cable system MV HV Superconducting MV cable system MV Substation in Substation in MV city center city center
AmpaCity One Line Diagram Initial Substation Dellbrügge Situation Substation Herkules 110-kV-cabel 10 kv 110-kV-cabel 10 kv 110 kv
AmpaCity One Line Diagram Current Substation Dellbrügge Situation Substation Herkules 10-kV-HTS-cable 110-kV-cabel SSB 10 kv Reduction of one transformer 110/10 kv 10 kv 110 kv
2,6 km 3,1 km 2,7 km 2,6 km 4,6 km 3,0 km Grid Layout with MV HTS Cables 110 kv OHL 110 kv UGC 10 kv UGC 110 kv busbar 10 kv busbar Bus tie (open) C 4,3 km A D 6,2 km 5,0 km 2,2 km B E Future grid structure has been designed based on Conventional 110 kv cables Superconducting 10 kv cables F Perquisites: same redundancy (n-1) Economic viability compared G 4,7 km H 3,6 km I 3,2 km J
2,7 km 2,7 km 2,6 km 2,6 km 8,4 km 3,0 km 3,0 km 4,6 km Grid Layout with MV HTS Cables 110 kv OHL 110 kv UGC 10 kv UGC 110 kv busbar 10 kv busbar Bus tie (open) C A 6,2 km B 5,0 km E D Dispensable devices for new grid concept 12.1 km of 110 kv cable systems 12 x 110 kv cable switchgear 5 x, 110/10 kv transformers 5 x 110 kv transformer switchgear 5 x 10 kv transformer switchgear F Additionally required devices for new grid concept 23.4 km of 10 kv HTS cable system 16 x 10 kv cable switchgear 3 x 10 kv bus ties G 4,7 km H 6,8 km J 3,6 km I 3,2 km
Concentric Cable Design for MV Applications Inner LN 2 Cooling Phase 1 Phase 2 Phase 3 Screen Former Dielectric Outer LN 2 Cooling Cable Cryostat
Superconducting fault current limiter Parameter Nominal power Nominal voltage Operating current Rated lightning impulse withstand voltage Rated AC withstand voltage Prospective unlimited peak current Prospective unlimited symmetric current Limited peak current Limited symmetric current Limitation time Recovery time Value 10 kv 2.3 ka 75 kv 28 kv 50 ka 20 ka < 13 ka < 5 ka 100 ms < 10 min
Cooling System Design > 4 kw cold power at 67 K > Subcooled pressurized nitrogen > Forced flow in closed circuit > High availability and reliability SFCL LN 2 storage tank vacuum pump sub cooler circulation pump pressure build-up HTS cable
Civil engineering an essential component for the realization of the project > Reduction of the expense and the negative impacts Less amount of space for the HTS system Division into construction phases Laying of empty conduits for cable pulling
Installation and pre-commissioning > Cable system Delivery > Cable system Assembly of the U-Bend > Cable system Pulling > Cable system Connection joint and joint pit
Installation and pre-commissioning > Superconducting fault currrent limiter Installation > Refrigeration system Delivery, installation of the LN-tank > Cable Refrigeration system system Pulling Mounting > On-site cable test Voltage test, tan d, PD
Commissioning Test Standard cable test with VLF equipment PD measurement (20 kv @ 0,1 Hz) Dielectric loss factor measurement (10 kv, 15 kv, 20 kv @ 0,1 Hz) AC withstand voltage test (30 kv @ 0,1 Hz for 1 h)
Operation Experience Lessons Learned > Balancing earth capacitance Compensation of unsymmetrical cable earth capacitances by installing capacitors > Cooling system optimization Modification of vacuum pumps after freezing of humidity and other smaller optimizations > Control system optimization Increase of response time after automatic reclosing for continuous operation after HV faults System operation since commissioning without problems, only few minor optimizations of cooling and control system during operation
15-12-01 15-12-08 15-12-15 15-12-22 15-12-29 16-01-05 16-01-12 16-01-19 16-01-26 16-02-02 16-02-09 16-02-16 16-02-23 Current in A Voltage in kv Voltage and Current 1000 8 875 7 750 6 625 5 500 4 375 3 250 2 125 1 0 0
15-12-01 15-12-08 15-12-15 15-12-22 15-12-29 16-01-05 16-01-12 16-01-19 16-01-26 16-02-02 16-02-09 16-02-16 16-02-23 Temperature in K Temperatures 77 76 75 74 Temperature Substation Dellbrügge 73 72 71 70 69 OutletTemperature Substation Herkules 68 67 Inlet Temperature Substation Herkules
15-12-01 15-12-08 15-12-15 15-12-22 15-12-29 16-01-05 16-01-12 16-01-19 16-01-26 16-02-02 16-02-09 16-02-16 16-02-23 Pressure in bar Pressures 10.0 9.5 Inlet Pressure Substation Herkules 9.0 8.5 8.0 7.5 Pressure Substation Dellbrügge 7.0 6.5 6.0 5.5 Outlet Pressure Substation Herkules 5.0
15-12-01 15-12-08 15-12-15 15-12-22 15-12-29 16-01-05 16-01-12 16-01-19 16-01-26 16-02-02 16-02-09 16-02-16 16-02-23 Mass Flow in g/s Liquid Nitrogen Mass Flow 500 480 460 440 420 400 380 360 340 320 300
15-12-01 15-12-08 15-12-15 15-12-22 15-12-29 16-01-05 16-01-12 16-01-19 16-01-26 16-02-02 16-02-09 16-02-16 16-02-23 Losses in W System Losses at Operating Temperature 2500 2350 2200 2050 1900 1750 1600 1450 1300 1150 1000
15-12-01 15-12-08 15-12-15 15-12-22 15-12-29 16-01-05 16-01-12 16-01-19 16-01-26 16-02-02 16-02-09 16-02-16 16-02-23 Level in % Liquid Nitrogen Storage Tank Level 100 90 80 70 60 50 40 30 20 10 0
Short Circuit Testing in Live Grid Operation Two short circuit tests, three phase short circuit current without earth contact One short circuit test, two phase short circuit current without earth contact One ground fault test, single phase with 5 minutes duration (isolated neutral) One short circuit test, single phase with neutral impedance (< 2 ka)
Current Strom in in ka ka 3-Phase Short Circuit Current 10 9 i_l1 8 7 i_l2 6 5 i_l3 4 3 2 1 0-1200 210 220 230 240 250 260 270 280 290 300 310 320-2 -3-4 -5-6 -7-8 -9 Time Zeit in in ms ms
Current in ka Strom in ka 2-Phase Short Circuit Current 9 8 i_l1 7 i_l2 6 i_l3 5 4 3 2 1 0-1200 210 220 230 240 250 260 270 280 290 300 310 320-2 -3-4 -5-6 -7-8 -9 Time Zeit in ms
Current Strom in in ka ka 1-Phase Short Circuit Current 2,4 2,0 1,6 1,2 0,8 0,4 0,0 200 210 220 230 240 250 260 270 280 290 300 310 320-0,4-0,8-1,2-1,6-2,0 i_l1 i_l2 i_l3-2,4 Time Zeit in in ms ms
Short Circuit Testing Results All tests conducted gave expected results Protokollierung von Strom und Spannung Betriebsparameter des Strombegrenzers AmpaCity system operates exactly as designed, including fault current limitation Tests prove maturity of technology under real grid Betriebsbereitschaft nach kurzer Erholzeit operating conditions Temperaturverlauf Strombegrenzer während wieder einsatzbereit Kurzschluss
HTS is the technology for future urban grids Feasibility study with very positive results; amongst others: HV/MV stations in conurbations can be dropped by using HTS systems smarter grid structures and less requirement of space by extension of the grid with HTS cables Testing the superconducting cable in practical use at RWE The field test in Essen proved the maturity of HTS system under real grid conditions Superconducting components will become more competitive to conventional technology increasing capacity for the production of superconducting tapes scaling effects for cable system production reduced development and engineering optimized cable laying
Questions are Welcome Frank Schmidt Nexans Deutschland GmbH Kabelkamp 20 30179 Hannover Frank.Schmidt@nexans.com