Kort introduktion till mig 1 Improved phase balancing scheme for 50 β 60 Hz electrified railways Radu Belea (Atkins), Bertil Klerfors (retired from ABB), Thorsten Schütte (STRI), Bruce Warner (ABB) 2 Background β trends β Net loads increase in size: ππ = πΉπΉ β π£π£ = ππ β ππ β π£π£ β’ β’ β’ β’ Higher power in motors Denser traffic Higher speed Longer and heavier freight β Renewable energy β’ Decentralized generation β’ Decommision of large fossil and nuclear β’ Reduced short circuit power 3 Background β public-grid frequency AC systems 4 Background β transformer feeding (1/7) β Neutral sections of catenary β Larger loads or weak grids => imbalance β Special transformer solutions: Scott, Leblanc, β¦ β’ If the two sections equally loaded β’ The three public grid phases are 5 Background β transformer feeding (2/7) 6 Background β transformer feeding (3/7) β Larger loads or weak grids => imbalance β Special transformer solutions: Scott, Leblanc, β¦ β’ If the two sections equally loaded β’ The three public grid phases are β’ SPC β Static Power Conditioners β Equals the two sectionsβs loads 7 Background β transformer feeding (4/7) 8 Background β transformer feeding (5/7) β Larger loads or weak grids => imbalance β Special transformer solutions: Scott, Leblanc, β¦ β’ If the two sections equally loaded β’ The three public grid phases are β’ SPC β Static Power Conditioners β Equals the two sectionsβs loads β’ Co-phase makes the sections in phase 9 Background β transformer feeding (6/7) 10 Background β transformer feeding (7/7) β Larger loads or weak grids => imbalance β Special transformer solutions: Scott, Leblanc, β¦ β’ If the two sections equally loaded β’ The three public grid phases are β’ SPC β Static Power Conditioners β Equals the two sectionsβs loads β’ Co-phase makes the sections in phase β SVC on 3-phase grid also used 11 Steinmetz compensation with separate 3-phase transformer 12 Steinmetz compensation with common three phase transformer 13 Static Reactive Power Compensation β Static VAr Compensator β’ Not going into details, but β¦ β’ Classically thyristors, reactors (TCR) and/or capacitors (TSC) β’ ππ β ππ 2 β STATCOM β’ β’ β’ β’ β’ β’ 14 More expensive Static Synchronous Compensator Modern, VSC-based (Voltage Source Converter) DC-capacitor is voltage source (βhalfβ converter) ππ β ππ β more stable Higher losses Upgrading of compensation unit to full frequency converter 15 Conversion of existing line β Good for new investments β’ Discussed & other solutions (EB article) β’ Or pure converter feeding β Upgrading existing electrified railway β’ Proposed solution β’ Existing connections, Ξ & Y, drawbacks presented 16 Feeder station with 60 degrees Vconnection 17 V-connection completed to full delta by a third single phase transformer 18 Wye-connection of secondaries with compensation line to line 19 W-connection of single phase transformers (or Ξ¨-connection) 20 W/Ξ¨-connection with series capacitor in the middle leg 21 W/Ξ¨-connection series capacitor applies for three-phase transformer 22 Completing feeder station for ATsystem 23 Completing feeder station for ATsystem (*- or Π-connection) 24 Load equalizing and power factor correction to cos(phi) = 1 25 Conclusions β Proposed solution β’ Good for upgrades β’ Existing components β’ Less complicated than many Asian solutions β Simpler compensation circuit for β’ Modern trains β’ Modest train regeneration β Intermediate solution β’ Balancing 2 phases, 3rd phase on ½ load β’ Pure active load from feeding grid ββ¦ 26
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