
•• Loughborough ., University University library AuthorlFiling Title ...... e~.~.ry:.~.. ~~.~.f. ..~~.~.~. Class Mark ....................................................................-r . Please note that fines are charged on ALL overdue items. 0403819059 11111111111111111111111111111111111111111111 RAILWAY INTERFERENCE MANAGEMENT TLM Modelling in Railway Applications by Adesegun A. Ogunsola A Doctoral Tbesis Submitted in partial fulfIlment of the requirements for the award of Doctor of Philosophy of Loughborough University June 2008 © Adesegun A. Ogunsola, 2008 et--- Date '2 '-/' o{ 0"t Class T ABSTRACT RAILWAY INlERFERENCE MANAGEMENT , TLM Modelling in Railway Applications by Adesegun. A. Ogunsola This thesis deals with the application of analytical and numerical tools to Electtomagnetic Compatibility (EMC) management in railways. Analytical and numerical tools are applied to srudy the electtomagnetic coupling from an alternating current (AC) electrified railway line, and to srudy the electtical properties of concrete strucrure - a widely used component within the railway infrasttucture. An electrified railway system is a complex disttibuted system consisting of several sub-systems, with different voltage and current levels, co-located in a small area. An analytical method, based on transmissions line theory, is developed to investigate railway electtomagnetic coupling. The method is used to srudy an electrified railway line in which the running rails and earth comprise the current rerum path. The model is then modified to include the presence of booster transformers. The analytical model can be used to srudy the railway current distribution, earth potential and electtomagnetic coupling - inductive and conductive coupling - to nearby metallic structures. The limiting factor of the analytical model is the increasing difficulty in resolving the analytical equation as the complexity of the railway model increases. A large scale railway numerical model is implemented in Transmission Une Matrix (TLM) and the electtomagnetic fields propagated from the railway model is srudied. As this work focuses on the direct application of TLM in ill railway EMC management, a commercially available TIM sofrware package is used. The limitation of the numerical model relates to the increased computation resource and simulation time required as the complexity of the railway model increases. The second part of this thesis deals with the investigation of the electrical properties of concrete and the development of a dispersive material model that can be implemented in numerical simulators such as TIM. Concrete is widely used in the railway as structural components in the construction of signalling equipment room, operation control centres etc. It is equally used as sleepers in the railway to hold the rails in place or as concrete slabs on which the whole rail lines are installed. It is thus important to understand the contribution of concrete structures to the propagation of electromagnetic wave and its impact in railway applications. An analytical model, based on transmission line theory, is developed for the evaluation of shielding effectiveness of a concrete slab; the analytical model is extended to deal with reinforced concrete slab and conductive concrete. The usefulness and limitation of the model is discussed. A numerical model for concrete is developed for the evaluation of the effectiveness of concrete as a shield. Initially, concrete is modelled as a simple dielectric material, using the available dielectric material functionality within TLM. It is noted that the simple dielecttic model is not adequate to characterise the behaviour of concrete over the frequency range of interest. Better agreement is obtained with concrete modelled as a dispersive material having material properties similar to that exhibited by materials obeying Debye equation. The limitations of the dispersive material model are equally discussed. iv The design of conductive concrete is discussed, these have application in the railway industry where old existing structures are to be converted to functional rooms to house sensitive electronic system. A layer of conductive concrete can be applied to the fa<;ade to enhance the global shielding of the structure. v TABLE OF CONTENTS Abstract ................................................................................................................................ ill Table of Contents ............................................................................................................... vi List of Figures ..................................................................................................................... ix List of Tables ...................................................................................................................... xii Acknowledgments ............................................................................................................ xiii Dedication .......................................................................................................................... xv List of Symbols ................................................................................................................. xvi Chapter 1.. ............................................................................................................................. 1 Introduction ......................................................................................................................... 1 1.1 The Relevance of Signalling ......................................................................... 2 1.2 Research Stimulus .......................................................................................... 3 1.3 Objective and Scope of Work ..................................................................... 6 1.4 Structure of Thesis ......................................................................................... 6 1.5 Achievements ................................................................................................. 7 1.6 References ....................................................................................................... 9 Chapter 2 ........................................................................................ " ... ,.""",."" , ...... ,.", ... ,.,11 An Overview of the Railway Environment.................................................................. 11 2.1 Power Supply Arrangement.. ..................................................................... l1 2.2 Power Supply from the Catenary to the Load (Train) .......................... 12 2,3 Return Current Path ....... ""."".................................................................... 14 2.3.1 Current Return via Running Rails Only .................................................. 14 2.3.2 Systems with Booster Transformers (ET) ......... " .................. " ................ 15 2.3.3 Auto-Transformers - an overview .. " ....................................................... 20 2,3.4 The Rail ............................. " ............. " .................................................... " ...... 21 2.4 Telecommunications and Signalling Systems ........................................ ,22 2.4,1 Telecommunications ............. " ................................. " ...................... " ......... 22 2.4,2 Signalling Systems ................................ " .................... " ................................ 23 2.5 Earthing and Bonding............ " ............ " ... " .......... " ..... " ............................ ,25 2,6 Summary ........................... " .......................... " .............................................. ,27 2.7 References .............................. " ............... " ................... " ............................... 27 Chapter 3....... """ ................................... " ................... " ............... " .................................... ,30 Interference Management in the Railway ..... " .... " ............................................... " ....... 30 3,1 Electromagnetic Interference .................................. " ................... " ....... " .. 30 3.2 Sources and Victims ofInterference ...... " ............... "" ............................ ,32 3,3 Signalling Interference Issues .............. " .................................................... 33 3.4 EMC Management ........ ""................. " .................... " ................................. 35 3.4.1 EMC-Safery Related Issues ... " .................... " .................. " ........... """ ..... ",38 3.4.2 Railway EMC Route to Compliance .. " ............. " ... " ............... """ .......... , 40 3.5 Summary ........ "" ..................................... " ............. " ................... " .......... " ..... 41 vi 3.6 References ..................................................................................................... 42 Chapter 4 ............................................................................................................................ .47 Low Frequency Coupling and Transmission Line Theory........................................ 47 4.1 Introduction .................................................................................................. 47 4.2 Earth - Rail Current Distribution ............................................................ .47 4.2.1 Running Rails ................................................................................................ 48 4.2.2
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