Experiences with Superconducting Cable & Fault Current Limiter in a German City Center Mark Stemmle

Transcription

1 Experiences with Superconducting Cable & Fault Current Limiter in a German City Center Mark Stemmle mark.stemmle@nexans.com i-pcgrid Workshop San Francisco, CA March 30 th, 2017

2 Agenda Introduction - Basics of Superconductivity - Cable Design for MV Applications - Advantages of Superconducting Cables AmpaCity Project - Motivation - Installation - Operation Experience - Short Circuit Current Testing What s Next? Conclusions 2 I i-pcgrid Workshop 2017 I

3 Electrical resistance Voltage Superconductivity Basics Superconductor Metallic conductor Metallic conductor Superconductor T c Temperature I c Current Electrical resistance drops to zero below critical temperature (T c ) Practical definition of critical current density (I c ) with 1 µv/cm criterion 3 I i-pcgrid Workshop 2017 I

4 Concentric Cable Design for MV Applications Inner LN 2 Cooling Phase 1 Phase 2 Phase 3 Screen Former Dielectric 4 I i-pcgrid Workshop 2017 I Outer LN 2 Cooling Cable Cryostat

5 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 5 I i-pcgrid Workshop 2017 I

6 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 6 I i-pcgrid Workshop 2017 I

7 AmpaCity Installation in Essen, Germany Technical specification - 1 km distance between substations - 10 kv system voltage ka operating current (40 MVA) 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 " 7 I i-pcgrid Workshop 2017 I

8 Cable Pulling First Length 8 I i-pcgrid Workshop 2017 I

9 Installation in Substation Dellbrügge 9 I i-pcgrid Workshop 2017 I

10 System Installation in Substation Herkules 10 I i-pcgrid Workshop 2017 I

11 Operation Experience > 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 11 I i-pcgrid Workshop 2017 I

12 Current in A Voltage and Current Voltage in kv I i-pcgrid Workshop 2017 I

13 Current (ka) Cooling System Design > 4 kw cold power at 67 K > Subcooled pressurized nitrogen > Forced flow in closed circuit Limited Current Prospective Current Nominal Current > High availability and reliability LN 2 storage tank vacuum pump sub cooler circulation pump pressure build-up SFCL Time (ms) HTS cable 13 I i-pcgrid Workshop 2017 I

14 Temperature in K Temperatures Temperature Substation Dellbrügge Outlet Temperature Substation Herkules Inlet Temperature Substation Herkules 14 I i-pcgrid Workshop 2017 I

15 Pressure in bar Pressures Inlet Pressure Substation Herkules Pressure Substation Dellbrügge Outlet Pressure Substation Herkules I i-pcgrid Workshop 2017 I

16 Mass Flow in g/s Liquid Nitrogen Mass Flow I i-pcgrid Workshop 2017 I

17 Losses in W System Losses at Operating Temperature I i-pcgrid Workshop 2017 I

18 Level in % Liquid Nitrogen Storage Tank Level I i-pcgrid Workshop 2017 I

19 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) 19 I i-pcgrid Workshop 2017 I

20 Current Strom in in ka ka 3-Phase Short Circuit Current 10 9 i_l1 8 7 i_l2 6 5 i_l Time Zeit in in ms ms 20 I i-pcgrid Workshop 2017 I

21 Current in ka Strom in ka 2-Phase Short Circuit Current 9 8 i_l1 7 i_l2 6 i_l Time Zeit in ms 21 I i-pcgrid Workshop 2017 I

22 Current in ka Strom in ka 1-Phase Short Circuit Current 2,4 2,0 1,6 1,2 0,8 0,4 0, ,4-0,8-1,2-1,6-2,0 i_l1 i_l2 i_l3-2,4 Time Zeit in in ms ms 22 I i-pcgrid Workshop 2017 I

23 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 operating conditions Betriebsbereitschaft nach kurzer Erholzeit Temperaturverlauf Strombegrenzer während wieder einsatzbereit Kurzschluss 23 I i-pcgrid Workshop 2017 I

24 ComEd Project (Chicago) In 2015 Nexans was chosen supplier for the project! 24 I i-pcgrid Workshop 2017 I

25 Conclusions Superconducting cable and fault current limiter technology has been successfully proven in real grid application AmpaCity system in operation for more than three years Performance during normal operation as expected Short circuit current behavior was verified in grid First commercial projects in progress (Chicago) 25 I i-pcgrid Workshop 2017 I

26 Thank you very much for your attention! Dr. Mark Stemmle Nexans Deutschland GmbH Kabelkamp Hannover 26 I i-pcgrid Workshop 2017 I