Transport. Rail. 0 distances x

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1 10.1 Dynamic Topology The complete system is compose of a eformable circuit between the energy supply by the sub-station an the train. The sub-station supplies energy at a voltage level aapte at the use possibility for a traction engine, it receive it at other characteristics, aapte at transport, from prouction site. Transport Prouction Rail Fig Schematic isposition of electric traction constitution The traction circuit is compose of two very ifferent conuctors: 1. The contact line isolate from supports, with a well known characteristics at construction. 2. The rails an surrouning fiel where current is ivie on unetermine manner. However, it is possible to raw a simplifie schema consiering all impeances. sub- Z locomotive 0 istances x Fig 10.4 : simplifie schema. As impeance Z, for a specifie type of construction, epens on istance, it is often spoken of linear impeance. Typical values of contact lines have been calculate for tracks with stanar traffic; for groun conuctor, mean values were chosen. Please note that the track construction nees careful ispositions in orer to guarantee the electric continuity in sort of the main part of current passes through rails. Jean-Marc Allenbach & Michel Comte

2 Linear impeance [ /km] Single track Double track 1,5 kv= 0,07 0,05 3 kv= 0,08 0,06 15 kv 16,7 Hz 0,08 + j 0,13 0,05 + j 0,08 25 kv 0,13 + j 0,35 0,09 + j 0,21 Fig Linear impeances for typical lines. The voltage effectively usable by the traction engine is one elivere by the substation, from which the voltage rop is subtracte. This voltage rop epens on the istance from the sub-station an from the intensity of the current aske by the traction engine. Not all lines are supplie by a single sub-station, but in particular inirect current, one section of length can be supplie at both ens [km] SS2 SS U R' [km] Fig Relatives tension rops on line. Jean-Marc Allenbach & Michel Comte

3 10.2 Constitution The sub-stations an the contact line are linke by contactors, to permit ifferent structures of traction circuit. f the parallel coupling of irect-current sub-stations on t get problems, in single-phase, the parallel coupling is only possible if both sub-stations have exactly the same phase. A Unit C B A 3 C 4 B 1 Track 1 Track 2 Departure unit of sub-station Switching station between 2 sub-stations Departure unit of sub-station Fig Coupling of two sub-stations To reuce the linear impeance in single-phase, a ual voltage in chosen in many times, with autotransformers in line. HT Autotransformers in line 50 kv Feeer Voie 25 kv 25 kv Figure Double single-phase power supply. Distances between sub-stations [km] Power per sub-station [MVA] Direct current 1500 V 8 to 14 3 to 12 Single-phase 16,7 Hz 15 kv 30 to to 30 Single-phase 25 kv 30 to to 30 Single-phase 2 x 25 kv 40 to to 60 Tableau ntervals an powers of sub-stations epening of systems The transformer efines the nominal power what furnish a sub-station, it can be overlae for a short time (for ex. 200%*P n uring 2 minutes). For irect-current sub-stations, the overloa will be limite by the maximal current of the rectifier. Jean-Marc Allenbach & Michel Comte

4 10.3 Power supply The single-phase contact lines are supplie from the general three-phase gri (fig a) through sub-stations three-phase single-phase who step own voltage. Care is taken on the best loa equilibrium of the three phases on the general gri by the sub-stations who follow each over on a line. The irect-current contact lines are also supplie from the general three-phase gri (fig c) through sub-stations transformer an three-phase rectifier. At the beginning of electric traction, it were foun irect current power plant who supply irectly the contact line. The single-phase contact lines at special frequency can be supplie from a singlephase gri an single-phase power plants (fig b) through sub-stations with single-phase transformers, or from the general three-phase gri (fig ) through frequency converter sub-stations or par through a combination of both moes. a) a) nustrial Fréquence frequency/ inustrielle inustrial / fré quenfrequency ce inustrielle Power Centrales plant e prouction Switching Postes 'interconn exion General Rése au HV- général gri H T Transformer Sous -stati ons à sub-station trans formateur Track Voie b) Special a) Fréquence frequency/special spéci ale / fréquence frequency spéciale Power plant Cen tra les e prouctio n Rése 16,7 au Hz - gri 16, 7 Hz Transformer sub-station Sous tions à trans formateur Track Voie 16,7 Hz 16,7 Hz c) nustrial c) Fréquence frequency/ inustrielle irect current / con tinu ) b) nustrial Fréquence frequency/special inustrielle / fréquen frequency ce spéci ale Power Cen trales plant e prouction Switching Post es 'in terco nn exion General Rése au HV- génégri ral H T Rectifier Sous -stasub- station rer ess eur tions à Track Voie 0 Hz Fig Different power supply possibility. Centrales Power plant e prouction Postes Switching 'interconn exion Rése General au général HV- gri H T Sous Converter -stati ons sub-station eur convertiss Voie Track ,7 Hz For frequency conversion, rotating converters were first use: rigi for special frequency without own prouction, weak for ones with an own supply. Now, static frequency converters are use, with intermeiate continuous voltage circuit (U-converter). So on threephase sie as on single-phase sie, elementary converters are installe in cascae, in orer to guarantee a low harmonic factor from chopper frequency. First implementations use GTO (CFF: Giubiasco) [122]. The recent realizations use GCT (DB: Bremen) [123] who permitte less conuction losses, 25 %, a reuction in a factor 5 to 6 of the gate-unit power an commutation time reuce in factor 6 to 8. These commutation times are similar as ones of GBT, who have greater conuction losses. The structure of a GCT is comparable at one of a GBT of same range, this permit quantity gain in the prouctions costs. These equipments are reversible. Jean-Marc Allenbach & Michel Comte

5 Such equipments are also thought between three-phase an single-phase [147]. For a moerate buying cost supplement compare to simple transformers, the using costs are reuce: No penalties to pay at the energy supplier for consumption asymmetry. Harmonics absorbe through filters on the intermeiate circuit. Reactive power furnishe by the intermeiate circuit. Voltage level is controlle at upper allowe value if sub-station supply power an at lower one if it absorb power. Transformer Converters ntermeiate Converters Transformers at Transfo. 3-phase circuit in parallel serie seconaries 16.7 Hz Fig Static frequency converter. For the irect-current lines power supply, rotating machines an mercury rectifiers are no more use toay. n general, single-irection ioe rectifiers are use. - U U 1 U 2 U 3 U Fig Three-phase rectifier. + U 2 U 3 U 1 n single-phase, we have seen than linear impeance is complex (fig ). This causes that the available voltage for the traction engine is lower than at sub-station output, but it is also shifte in phase (fig.10.69a). n place of reucing sub-station intervals, with great costs, capacitor rack can be implemente on line, in series with contact line (RhB, NSB, fig b) or in parallel SNCF, fig c). Not only the voltage at contact line is better, but also the reactive power, who is supplie by the sub-station is lower: the phase ifference ss between voltage at sub-station an the furnishe current is lower. Jean-Marc Allenbach & Michel Comte

6 R X L R X L X C R X L t R L R L C R L c X C R R L L C R L ss t ss C T t ss t Fig Voltage rop compensation on single-phase by capacitor. Better than using passive components who helps only on certain parts of lines for certain loa cases, we use toay static voltage compensators (SVC) who combine batteries of selfs et capacitors with semiconuctors controlle by a software who survey in real time voltages an currents at contact line. The impeance value can be aapte at the real loa conition at contact line. Ligne e contact Ligne e contact Ligne e contact Rails Rails Rails a/ Schéma e base b/ schéma avec inuctance commutée Fig Static voltage compensators for reactive power. c/ schéma complet avec capacités contrôlées et filtres The irect-current sub-stations are consiere as real voltage sources ajuste for U 0, with an internal resistance R i an conceive for a nominal current ssn. They may be shortly overloae. U ss U R (10.75) 0 i ss ss2h,5 ssn ss1min 3 1 (10.76) ssn n single-phase, internal impeance has to be consiere. They may be shortly overloae. ss15min,5 ssn ss5min 2 1 (10.77) ssn Jean-Marc Allenbach & Michel Comte