High Performance Railway Power

Transcription

1 High Performance Railway Power Introduction to Autotransformer system (AT) Banebranchen Session infrastructure May 9th 2012 Tommy O. Jensen/Atkins Danmark 1

2 Agenda Historical AT system reinvented Principle of operation AT supply system AT system at HSL-railways AT system in Sweden AT system in Norway Advantages/drawbacks of AT Suitable for use in Denmark? 2

3 Historical Valtellina 3 kv 15 Hz, Italien1902 Introduction of AC-systems 1900 AC locomotives are introduced Ganz develops the first AC locomotive (3 kv) 1905 Many AC systems open in the eastern US, among others New York New Haven (11 kv) 1910 Auto transformer supply tends to become a standard on densely traficated lines in USA (e.g. AT-systems +11/-22 kv 25 Hz) 1915 The Iron Ore line Kiruna-Narvik was electrified (15 kv 15 Hz with 80 kv supply) New Haven-system 11/22 kv 25 Hz CG1- loco at kw New York

4 AT system reinvented Increased demands for power necessitates new solutions for train power systems 1972 Japan, Sanyo Shinkansen (25/25 kv 60 Hz) 1981 France, TGV Paris-Lyon (25/25 kv 50 Hz) 1987 Hungary, simplified AT system (25/25 kv 50 Hz) 1995 Sweden, Kiruna Svappavaara (15/15 kv 16,7 Hz) Suitable for busy conventional railways, heavy haul and high speed lines. Substations are expensive and technical complicated installations. 4

5 Operation for Auto Transformer Principle of operation for an Auto Transformer 250 A e 1 +e 2 e A Ampere winding balance: I 1 N 1 = I 2 N 2 ( the ideal transformer ) Power for autotransformator: S AT = U 1 I 1 = U 2 I 2 Common winding = reduced weight, smaller volume, reduced losses Lower price compared to normal two winding transformer. Option for low leak reactance, particularly important in a train power system Draw back no galvanic separation (easier "path" for short circuit currents) 5

6 Terminology for AT systems Normally used terms: Auto transformer only has one coil with three terminations Primary and secondary side have no galvanic separation *) Plus conductor is connected to contact wire and positive feeder (PL) Minus conductor is only connected to negative feeder (NL) Midpoint termination ideally 0 V is connected to track / return circuit Angel between plus and minus conductors is 180 Normal designations are 2x25 kv or +25/-25 kv *) Power supply (transformer) from the high voltage grid, e.g. 220 kv, will normally be galvanic separated from the train power system. 6

7 AC supply system Direct supply running rail (RR) or Direct supply with return conductor (RC) Return conductor RC 7

8 AC supply systems Booster transformer with return conductor (BT-RC) 8

9 AC supply systems Auto transformer with full range voltage supply (AT-2U) Train power transformer with two secondary coils 9

10 AC supply systems Auto transformer with contact wire voltage supply (AT-1U) Train power transformer equipped with one secondary coil Some times named AT-Light 10

11 AC supply systems Earth currents with direct supply (RR) Earth currents with direct supply with return conductor (RC) 11

12 AC supply systems Earth currents with BT system Earth currents with AT system 12

13 AC supply systems Why choose a complicated AT system? Source: Comparison of BT and AT system, EMC-symposium York 1-2. July Prof. György Varju, Budapest University Because supply conditions will improve significantly! 13

14 AC supply systems Why choose a complicated system? NL (-25 kv) Inductance in an overhead line AC system is heavily dependent on the geometric design PL (+25 kv) CL (+25 kv) Inductance can be reduced by a symmetric configuration and small distances between conductors Reduced EMC impact on the surroundings and reduced stray currents with balanced impedances in PL and FL (reduced "leakage" of currents) RR (0 kv) 14

15 AC supply systems Why choose a complicated system? Principle of supply (normal operation) Relative impedance Acceptabel distance single track Booster transformer (BT-RC) 100 % km Direct (RR-RC) ~ 65 % km Direct with supply feeder (RR-RC-FL) ~ 60 % km Auto transformer (AT) ~ % km Possible increased distance between substations Significantly improved quality of voltage Reduced losses Better utilization of brake energy 15

16 AT system at HSL-railway French AT transformer 225 kv /2x27,5 kv Nominal power 72 MVA (36-36 MVA) SNCF TGV 16

17 AT system at HSL-railway Electric layout for AT supply Supply station, feeder cables, substation 17

18 AT system in Sweden Supply system with distributed auto transformers ( AT-Light ) Source: BVS Kraftförsörjningsanläggningar Autotransformatorsystem systembeskrivning, 18

19 AT system in Sweden Supply system with distributed auto transformators ( AT-Light ) Banverket AT system 2 x 15 kv AT-transformers 5 MVA Used at Vännas Umeå line 19

20 AT system in Sweden Supply system with distributed auto transformators ( AT-Light ) 20

21 AT system in Norway Supply system with distributed auto transformators ( AT-Light ) Omformerstasjon 15 kv samleskinne returstrøm samleskinne 1o km 1o km 1o km Negativledning NL -15 kv Positivledning PL + 15 kv Kontaktledning KL + 15 kv 21

22 AT system in Norway 22

23 AT system in Norway 23

24 Advantages / drawbacks AT-system AT system compared to BT system + Very low voltage drop in overhead catenery system. + Reduced losses in overhead catenary system = saved energy! + Auto Transformer every 10th km compared to Booster Transformer every 3rd km. + Possible longer distance between substations. - More conductors mounted in overhead catenary system. - More complicated switching equipment in train power system - Risk of locally higher earth current caused by higher power levels. BT system employed on lines with parallel signaling and telecommunication cables in order to avoid electromagnetic disturbances. AT system can offers the same advantages. AT system is widely used on high speed lines and railways with heavy freight traffic. AT system can be used on long single track lines to reduce numbers of substations. 24

25 AT system interesting in Denmark? Electrification 2011 Existing network too expensive to rebuild. Cost for Kystbanen estimated at 120 mio.kr! Lines to be electrified in the future could prove interesting. 25

26 AT system interesting in Denmark? Electrification till 2020 Lunderskov-Esbjerg København - Ringsted Ringsted Rødby/Femern Note: Yellow substations not yet decided! 26

27 AT-system interesting in Danmark? Probable development after 2020 The rest of Sealand Main lines in Jutland Other local lines

28 Banebranchen Session 2012 May 9th Thank you for your attention! Electric railway at Skærum Teglværk 1909 Electric railway at Ørestad 2012 Questions? 28