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Modeling of Passive Series Devices on Multiconductor Transmission Lines for Transient Analysis in Power and Railway Systems
Uppsala University.
Uppsala University.
Uppsala University.ORCID iD: 0000-0002-1607-2493
2008 (English)In: EuroEM Conference 2008, 2008Conference paper (Refereed)
Abstract [en]

Usually the crosstalk or field to wire coupling mechanisms in multiconductor transmission lines (MTL) are studied considering lumped loads or devices connected at the line terminations (at source and load ends) or as shunt load to ground along the lines, as seen in conventional power system networks e.g. [1-3]. However there are practical systems, e.g. in typical Swedish railway systems, wherein discrete devices exist in series with the line (booster transformers) or in shunt between the lines (auto transformers and track circuits). With lightning transients various parameters that influence crosstalk in MTL systems, such as the ground conductivity, have been analyzed e.g. in [1].

We shall present various cases of crosstalk mechanisms when the devices are connected either in series with the line or in shunt between the lines. The method used for simulating the voltage and current pulse propagation along the MTL systems is the FDTD method [4] in conjunction with the recursive convolution proposed in [5] for inclusion of ground losses. The passive series components connected along the MTL are simulated by the circuit solver ATP/EMTP [6, 7]. Emphasis will be given to present the model that connects the FDTD routine with the circuit solver in a more efficient way. The currents entering or leaving a given type of component at a given position along the lines are modeled as time dependant current sources in the circuit solver and the terminal voltages appearing in the circuit are returned to the FDTD routine as node voltages.

We shall also present the efficacy of the proposed method and mathematically discuss the validity of the present work. The influence of finitely conducting ground on the current pulse propagation is also included in the analysis. From the crosstalk analysis it is also shown that the series connected passive devices cannot be disregarded as they largely influence pulses propagating on the lines in the event of transient phenomena due to lightning or switching. This study could be beneficial for future practical studies of surge protection and insulation coordination.

Place, publisher, year, edition, pages
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
URN: urn:nbn:se:kth:diva-11936OAI: diva2:290562
European electromagnetics (EUROEM), 2008. Lausanne. July 21-25 2008
QC 20111117Available from: 2010-02-01 Created: 2010-01-27 Last updated: 2011-11-17Bibliographically approved
In thesis
1. Multi-conductor transmission line model for electrified railways: A method for including responses of lumped devices
Open this publication in new window or tab >>Multi-conductor transmission line model for electrified railways: A method for including responses of lumped devices
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

For studying the response to transients caused by lightning and other electromagnetic disturbance sources, electrified railway systems can be represented as a system of multiconductor transmission lines (MTL) above a finitely conducting ground. The conductors present in this system would be wires for traction power supply, auxiliary power, return conductors for traction current, the tracks, and finitely conducting ground. In contrast to conventional power systems, where the MTL system is usually only terminated at the line ends, there are lumped devices connected in series and as shunt along the railway network, for example, booster and auto transformers, track circuits, and various interconnections between conductors, influencing surge propagation. In this doctorial thesis a new method for incorporating lumped series and shunt connected devices along MTL systems is presented. Telegrapher’s equations, using the finite difference time domain method, are adopted for finding surge pulse propagations along the MTL systems, simultaneously solving for the lumped devices connected along the lines by means of Kirchoff’s laws for nodal currents and voltages using a circuit solver.

As part of this work, case studies are carried out to determine voltages appearing across devices connected along MTL systems representative of a typical Swedish single-track electrified railway system, in cases of direct and indirect lightning strikes. The influence of soil ionization at the grounding points and the nonlinear phenomenon of flashovers between overhead wires and the poles are also investigated. The calculations made show that the devices connected along this system, which are needed for normal and safe operation of the railway system, and nonlinearities are affecting the surge current and voltage distribution and peaks appearing along the MTL system and across devices.

Place, publisher, year, edition, pages
Stockholm: KTH, 2010. x, 80 p.
Trita-EE, ISSN 1653-5146 ; 2010:006
urn:nbn:se:kth:diva-11964 (URN)978-91-7415-557-0 (ISBN)
Public defence
2010-02-24, F3, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)
Available from: 2010-02-01 Created: 2010-02-01 Last updated: 2012-03-26

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Mazloom, ZiyaThottappillil, Rajeev
Electrical Engineering, Electronic Engineering, Information Engineering

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