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DC TractionPower SupplyPowerful, efficient and safesiemens.com/rail-electrification

More people, more challenges,one solutionDemographic change, urbanization and climate change: theseare the global trends of todayand tomorrow. For the worldpopulation is not only growing,it’s also getting older. Currentforecasts expect it to rise to9.2 billion by 2050.These people will need efficienttransportation and logistics.And that calls for innovativeelectrification solutions.2

Needed more than ever before:efficiency and sustainabilityNot only the world’s population will continue to grow in the coming years, urbanization will also be on the increase. So much sothat experts are predicting that 90 percentof future population growth will be concentrated in cities.Such trends mean however that trafficdensities all over the world will likewiseincrease – and with them the demand forintelligent, sustainable solutions for mobility.Intelligent and efficientrail electrification solutionsConcepts that make transport more efficientare in demand with the ever-increasing needfor mobility. With our long-standing transport-expertise and out IT know-how, we areconstantly developing new, intelligentmobility solutions that increase availabilityof infrastructure, optimize throughput andimprove passenger experience. It s in howwe electrify, automate and digitalize infrastructure that we re setting the benchmarkfor tomorrow s mobility – today.Optimal service – a competent partnerYou can benefit from our decades of experience in the engineering, construction andcommissioning of DC traction power supplysystems. As one of the world’s leadingsuppliers of electrotechnical plants andinnovative technology partner to all majorrail operators, we offer you all services fromone source and enable you to tap a lot ofpotential savings. Savings made possible byenergy-efficient, heavy-duty traction powersupplies and by even more reliable systemsand enhanced performance capabilities.And by engineering tools which uncoveropen questions as early as the project analysis phase.Place your trust in our ability to take a goodcomponent and make an even better traction power supply system. When it comes tomass transit, regional and main-line railways, we are the right partner for your DCtraction power supplies, for consultationand planning, for project implementationand commissioning, and for worldwideservice.3

Profit from our know-how:Sustained performance foryour successFor reliable traction power supply systems, you need anexperienced partner whoknows the alternatives andmakes the advantages clear toyou.This is why we start our workwith a thorough analysis of allthe static and dynamic aspectsof your project. It establishesthe prerequisites for customized engineering andfor a future-oriented solutionthat meets your requirementsreliably and efficiently.4

Extremely well advisedWe see your traction power supply systemwithin a wider context, in which the performance of your system can be directlyaffected through the interfaces.Our work therefore starts with a thoroughanalysis of the project conditions and theinterfaces. It allows us to correctly estimatethe overall implications of the project. Weuse it as the basis for developing the alternatives, the effects of which we investigatewith the aid of simulation tools which wehave developed ourselves.Saving energy and costsBy taking this wide-ranging approach toprojects we avoid problems at interfacesand dimension the network correctly rightfrom the start. This particularly affects thenumber, spacing, output and consequentlythe optimal location of the DC substations.During the system design, we work out thebest compromise between the structuralpossibilities and the technical requirementswhich are determined by the followingcriteria: Voltage drop on the overhead contact line Operation in case of substation failure Stray currents / rail potentials LossesSecurity for your decisionWe evaluate your network on the basis of atrain movement simulation, which thenforms the basis for the system design. Ourspecialized Sitras Sidytrac software makesit possible to optimize energy consumption,regenerative behavior, potential for savingenergy and many other factors.Sitras Sidytrac calculates all the characteristics of the power supply for your railwaysystem as a function of train operations,taking into account the interactions between vehicle and overhead contact linesystem during regenerative feedback. Earthing and the return current circuit are integral parts of the system design. That givesyou security.A separate concept is prepared and specifiesthe principles for grounding, includinglightning and overvoltage protection, for allof the systems involved: Negative return High- and medium-voltage systems Traction power supply Low voltage system Buildings, structures and infrastructuralfacilitiesAll this successfully results in a tractionpower supply system offering the lowest lifecycle costs and meeting your requirementsof today as well as tomorrow.Electromagnetic compatibilityOur Sitras EMF simulation tool has beenspecially developed to calculate the magnetic fields around traction power supplysystems.This calculation is a main part of the EMCplanning, with which we eliminate interferences and ensure operator and plant protection throughout all systems.5

DC power supply for masstransit and main-line railways:Economical and efficientWith our complete solutions,we offer many opportunities forsustained cost reduction.You can profit from our vastsystem know-how in mass transit service and DC operationof main-line railways. It givesyou decisive advantages in theplanning and dimensioning ofyour traction power supply.6

Reliability: the all-important factorTraction power supplies can be trimmeddown for the sake of a low purchase price,but that does not help you if it is achieved atthe expense of reliability. We mean something else when we speak of a cost-efficientsolution: for us, it is important to placepriority on the reliable operation of ourcustomer’s railway system – at optimizedcosts.It also means that the DC substations haveto fulfill the characteristic requirements ofmass transit and main-line railways. In masstransit, these are above all the short distances between stations, high starting acceleration rates and high train densities combinedwith less space for overall network expansion and therefore more tightly intermeshednetworks.DC traction power supply solutions for mainline railways have to meet completely different requirements due to their differenttransportation parameters. Longer distancesbetween stations have to be taken intoaccount and, of course, much more electricity has to be transported over a much largerroute network.The starting situation, however, is the samefor both mass transit and main-line railways.The voltage from the three-phase mediumvoltage network is converted in the DCsubstation and the three-phase current isrectified. The direct current is then fed intothe various track sections of the overheadcontact line system.factor when locating the substations is tokeep the path of the current to the vehiclesas short as possible. We therefore locate theDC substations directly at the tracksidewherever possible.Thanks to their compact modular design,this is not usually a problem so they can bepositioned under optimal conditions duringthe system design phase. This avoids longcable routes and the energy losses associated with them.Flexibility of constructionThe extremely compact dimensions of themodules ensure high flexibility in the construction of our substations. For example,we can integrate your substation into anexisting building or, as an alternative, installit in previously unused tunnel spaces.Prefabricated buildings are another cost andtimesaving option. We can even install yoursubstation in a container to give you maximum flexibility and the shortest projecttime. These containerized substations canreduce on-site assembly and commissioningwork to a minimum.Built-in economyWith our perfectly harmonized modularportfolio, we are one of the few completeproviders of DC traction power supplies. Letyour company take advantage of a compre hensive solution from a single source – asolution offering everything from engineering and system components to installation,commissioning and after-sales service.Short distances for higherenergy efficiencyWhile the lower voltages of direct currentoffer many advantages in terms of safetyand structural requirements, the crucial7

Intelligent tractionpower supply:For sustainable mobilityFor you as a rail operator, theincreasing costs of energy andother resources are making theenergy management in yournetwork more important thanever before.Profit from our ideas: transforming braking energy intoelectricity for later use is justone of many new perspectivesthat we have to offer.8

Success through clean mobilityIt is equally important to improve the ecofriendliness and economy of mass transitsystems in order to make them more attractive to the public, especially in large metropolitan regions. We contribute to this endeavor by enabling you to save up to 30percent on energy and by increasing thelong-term attractiveness of your transitservices.Optimized energy balanceSitras Sidytrac – our design and optimization program – plays a decisive role in theenergy management of your system. We useit to calculate your entire DC traction powersupply system in advance – and with an eyeon energy management even at this earlystage. This analysis is then used to plan yourDC traction power supply system, to meet toyour requirements, and to optimize energyconsumption and regenerative behavior.Thus, we not only improve the ecologicalaspects of your system but also, when allmeasures have been implemented, sustainably reduce your costs.During operation, our intelligent energymanagement system Sitras iEMS supportsyou with full energy transparency and loadmanagement.Key innovationsOur energy management components arebased on the years of experience gained byour engineers in all areas of traction powersupplies, and the latest research and development results.With a self-commuted IGBT inverter Sitras PCI the energy distribution in thecomplete traction power supply grid can beoptimized. The increased demands regarding power quality are fulfilled and thequality of the recovery is enhanced. Additionally to the recovery of energy intothe medium-voltage grid, reactive powercompensation can be carried out.9

Perfection in detail:One modular systemfor all applicationsIn addition to the proven standard products from theindustrial area, the Sitras product family enables us tooffer an optimum solutionfor every function in the substation. It has been speciallydeveloped under the aspectthat a large number of indi vidual components have to beintegrated to form one perfectsystem.10

1 Medium-voltage switchgear5 Protective devices2 Rectifier transformer6 Station control system3 Rectifier7 Short-circuiting device4 DC switchgear8 Auxiliary power supply22837541611

Siemens AGMobility DivisionOtto-Hahn-Ring 681739 MunichGermanyE-mail: m/mobilityArticle No. MOTP-B10005-00-7600Printed in Germany AL N ECCN NDispo 6403fb 7209 WS 08160.5Sitras is a registered trademark of Siemens AG.All rights reserved.Trademarks mentioned in this document are the propertyof Siemens AG, its affiliates, or their respective owners.Subject to change without prior notice.The information in this document contains generaldescriptions of the technical options available, whichmay not apply in all cases. The required technicaloptions should therefore be specified in the contract.

mobility solutions that increase availability of infrastructure, optimize throughput and improve passenger experience. It s in how we electrify, automate and digitalize infra-structure that we re setting the benchmark for tomorrow s mobility – today. Optimal service – a competent partn