Optimal operation of the Swedish railway electrical system

Olofsson, Magnus; Andersson, Göran; Söder, Lennart

doi:10.1049/cp:19950179

Cited by 24 publications

(48 citation statements)

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“…Even with a very simple control, such as the one used in rotating converters in Scandinavia today (Abrahamsson, 2008;Olofsson, 1996Olofsson, , 1993, where the voltage is adjusted downwards from unity for reactive power production on the catenary side, and conversely upwards for reactive power consumption on the catenary side; the loss profile would theoretically be better than with pure transformer feeding. Rotary converters allow much more flexible control of active and reactive power than this.…”

Section: Voltage Controlmentioning

confidence: 99%

Use of converters for feeding of AC railways for all frequencies

Abrahamsson¹,

Schütte²,

Östlund³

2012

Energy for Sustainable Development

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Railways are the most energy-efficient land-based mode of transport, and electrification is the most energy-efficient way to power the trains. There are many existing solutions to supply the trains with electricity. Regardless of which particular technology is chosen, it is beneficial to interconnect the public power grids to grids supplying power to the railways. This paper shows that the most efficient, flexible, and gentle-for-the-public-grid way of doing that is through powerelectronics-based power converters. Converters offer great benefits regardless of whether the overhead contact lines are of DC-type or AC type, and regardless of the AC grid frequency. This paper presents neither new theory nor new experimental results. Based on already available information, this paper presents logical arguments leading to this conclusion from collected facts. Over time what used to be advanced and high-cost equipment earlier can nowadays be purchased at reasonable cost. It is obvious that for most electrically-fed railways, the use of modern power converters is attractive. Where the individual trains are high consumers of energy, the railway gradients are substantial, and the public grids feeding the railway are weak, the use of converters would be technically desirable, if not necessary for electrification.It is expected that more high-speed railways will be built, and more existing railways will be electrified in the foreseeable future. This paper could provide some insights to infrastructure owners and decision makers in railway administrations about value additions that converter-fed electric railways would provide.

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Section: Voltage Controlmentioning

confidence: 99%

Use of converters for feeding of AC railways for all frequencies

Abrahamsson¹,

Schütte²,

Östlund³

2012

Energy for Sustainable Development

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“…For details of how the Swedish railway power supply system is constituted and can be simulated, please refer to [8], [25]- [27].…”

Section: Comparative Case Studiesmentioning

confidence: 99%

“…The characteristics of rotary and rotary-mimicking converters are given in e.g. [30], [31]. The voltage is controlled so that it is constant or slightly decreasing with increasing reactive load.…”

Section: Modellingmentioning

confidence: 99%

High-voltage DC-feeder solution for electric railways

Abrahamsson

Kjellqvist

Östlund

2012

IET Power Electron.

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Abstract-For AC railway power supply systems with a different frequency than the public grid, high-voltage AC (HVAC) transmission lines are common, connected to the catenary by transformers. This paper suggests an alternative design based on an HVDC (High Voltage DC) feeder, which is connected to the catenary by converters. Such an HVDC line would also be appropriate for DC-fed railways and AC-fed railways working at public-grid frequency.The converter stations between the public grid and the HVDC feeder can be sparsely distributed, not denser than on 100 km distances, whereas the converters connecting the HVDC feeder to the catenary are distributed denser. Their ratings can be lower than present-day substation transformers or converters, since the power flows can be fully controlled.Despite a relatively low power rating, the proposed converters can be highly efficient due to the use of medium frequency technology. The proposed feeding system results in lower material usage, lower losses and higher controllability compared to present solutions.Simulations of the proposed solution show clear advantages regarding transmission losses and voltages compared to conventional systems, especially for cases with weak feeding, and when there are substantial amounts of regeneration from the trains.

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“…In converter stations with several converters of the same kind, P G , Q G , and Q 50 (the total active, reactive, and 50 Hz side reactive power generations, respectively) can simply be divided by the number of converters, # conv , in order to give the proper U and ψ values [6].…”

Section: Electrical and Mechanical Power For Each Time Stepmentioning

confidence: 99%

“…The phase shift on the 50 Hz side of the converter due to train power consumption is, according to [6],…”

Section: Electrical and Mechanical Power For Each Time Stepmentioning

confidence: 99%

Fast calculation of the dimensioning factors of the railway power supply system

Abrahamson¹,

Söder²

2007

WIT Transactions on Modelling and Simulation, Vol 46

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Because of environmental and economical reasons, in Sweden and the rest of Europe, both personal and goods transports on railway are increasing. Therefore great railway infrastructure investments are expected to come. An important part of this infrastructure is the railway power supply system. Exactly how much, when and where the traffic will increase is not known for sure. This means investment planning for an uncertain future. The more uncertain parameters, such as traffic density and weight of trains, and the further future considered, the greater the inevitable amount of cases that have to be considered. When doing simulations concerning a tremendous amount of cases, each part of the simulation model has to be computationally fast -in real life this means approximations. The two most important issues to estimate given a certain power system configuration, when planning for an electric traction system, are the energy consumption of the grid and the train delays that a too weak system would cause. In this paper, some modeling suggestions of the energy consumption and the maximal train velocities are presented. Two linear, and one nonlinear model are presented and compared. The comparisons regard both computer speed and representability. The independent variables of these models are a selection of parameters describing the power system, i.e.: power system technology used on each section, and traffic intensity.

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Optimal operation of the Swedish railway electrical system

Cited by 24 publications

References 0 publications

Use of converters for feeding of AC railways for all frequencies

Use of converters for feeding of AC railways for all frequencies

High-voltage DC-feeder solution for electric railways

Fast calculation of the dimensioning factors of the railway power supply system

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