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Numerical study on multi-pantograph railway operation at high speed
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.ORCID iD: 0000-0001-7393-569X
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Multi-pantograph operation allows several short electric multiple unit (EMU) trainsets to be coupled or decoupled to adapt to daily or seasonal passenger-flow variation. Although this is a convenient and efficient way to operate rolling stock and use railway infrastructure, pantographs significantly influence each other and even significantly change the dynamic behaviour of the system compared to single-pantograph operation in the same condition. The multi-pantograph system is more sensitive and vulnerable than the single-pantograph system, especially at high operational speeds or with pantographs spaced at short distances. Heavy oscillation in the system can result in low quality of current collection, electromagnetic interference, severe wear on the contact surfaces or even structural damage. The mechanical interaction between the pantograph and the catenary is one of the key issues which limits the maximum operational speed and decides the maintenance cost.

    Many researchers have paid a lot of attention to the single-pantograph operation and have made great progress on system modelling, optimizing, parameter studies and active control. However, how the pantographs in a train configuration affect each other in multi-pantograph operation and which factors limit the number of pantographs is not fully investigated. Nowadays, to avoid risking operational safety, there are strict regulations to limit the maximum operational speed, the maximum number of pantographs in use, and the minimum spacing distance between pantographs. With the trend of high-speed railways, there are huge demands on increasing operational speed and shortening spacing distance between pantographs. Furthermore, it is desirable to explore more practical and budget-saving methods to achieve higher speed on existing lines without significant technical modification.

    In addition to a literature survey of the dynamics of pantograph-catenary systems, this thesis carries out a numerical study on multi-pantograph operation based on a three-dimensional pantograph-catenary finite element (FE) model. In this study, the relationship between dynamic performance and other parameters, i.e. the number of pantographs in use, running speed and the position of the pantographs, are investigated. The results show that the spacing distance between pantographs is the most critical factor and the trailing pantograph does not always suffer from deterioration of the dynamic performance. By discussing the two-pantograph operation at short spacing distances, it is found that a properly excited catenary caused by the leading pantograph and the wave interference between pantographs can contribute to an improvement on the trailing pantograph performance. To avoid the additional wear caused by poor dynamic performance on the leading pantograph and achieve further improvement at high speeds, it is suggested to use the leading pantograph as an auxiliary pantograph, which does not conduct any electric current and optimize the uplift force on the leading pantograph. After a brief discussion on some system parameter deviations, it is shown that a 30% of speed increase should be possible to achieve while still sustaining a good dynamic performance without large modifications on the existing catenary system.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2015. , xiv, 36 p.
Series
TRITA-AVE, ISSN 1651-7660 ; 2015:64
Keyword [en]
numerical study, pantograph-catenary system, multi-pantograph operation, dynamic behaviour, high-speed operation
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Fordonsteknik
Identifiers
URN: urn:nbn:se:kth:diva-173943ISBN: 978-91-7595-683-1 (print)OAI: oai:DiVA.org:kth-173943DiVA: diva2:856402
Presentation
2015-10-14, VEL Vehicle Engineering Lab, Teknikringen 8, KTH Royal Institute of Technology, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

QC 20150928

Available from: 2015-09-28 Created: 2015-09-24 Last updated: 2015-09-28Bibliographically approved
List of papers
1. Implications of the operation of multiple pantographs on the soft catenary systems in Sweden
Open this publication in new window or tab >>Implications of the operation of multiple pantographs on the soft catenary systems in Sweden
2015 (English)In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 53, no 3, 341-346 p.Article in journal (Refereed) Published
Abstract [en]

Trains operating with several pantographs are used in Sweden and other countries. The more complex operational conditions, however, cause additional difficulties, i.e. low quality of current collection, increased mechanical wear and electromagnetic interference, due to the poor dynamic behaviour of the system. In order to address these problems, a three-dimensional model for the computational analysis of the interaction between catenary and pantograph is presented and validated in this paper, and the dynamic behaviour of the multi-pantograph system, based on Swedish soft pantograph/catenary systems, is analysed. Parametric studies are performed to investigate cases with different distances between pantographs and with up to three pantographs in use. The relationship between dynamic performance and other parameters, i.e. the number of pantographs in use, running speed and the position of the pantographs, is studied. The results show that an appropriate distance between pantographs and a given type of catenary allow operation on the existing infrastructure with up to three pantographs while maintaining an acceptable dynamic performance at the desired speed.

Place, publisher, year, edition, pages
Sage Publications, 2015
Keyword
Multi-pantograph operation, soft pantograph-catenary system, dynamic interaction, contact force
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:kth:diva-174045 (URN)10.1177/0954409714559317 (DOI)000371084800027 ()2-s2.0-84975741770 (Scopus ID)
Funder
Swedish Transport Administration
Note

QC 20160330

Available from: 2015-09-28 Created: 2015-09-28 Last updated: 2017-10-09Bibliographically approved
2. Possible speed increase on soft catenary system with help of auxiliary pantograph
Open this publication in new window or tab >>Possible speed increase on soft catenary system with help of auxiliary pantograph
2016 (English)In: The Dynamics of Vehicles on Roads and Tracks - Proceedings of the 24th Symposium of the International Association for Vehicle System Dynamics, IAVSD 2015, CRC Press, 2016, no 3, 927-936 p.Conference paper, Published paper (Refereed)
Abstract [en]

Stiffness variations and wave propagation in the catenary system cause high dynamic variations in the contact force between pantograph and catenary at high operating speeds. In order to increase the operational speed on an existing catenary system, especially on soft catenary systems, technical upgrading is usually required to keep the current collection quality within an acceptable range. Therefore, it is desirable to explore a more practical and costsaving method to achieve higher operational speed. With the help of a 3D pantograph-catenary finite element (FE) model, a parametric study on two-pantograph operation at short spacing distances is carried out. Results show that although the leading pantograph suffers from deterioration of dynamic performance, the trailing pantograph achieves a better dynamic behaviour by using a proper spacing distance between pantographs. To avoid the additional wear caused by poor dynamic performance on the leading pantograph, it is suggested to use the leading pantograph as an auxiliary pantograph, which does not conduct any electric current. In this way, the operational speed of the existing system can be increased while still sustaining a good dynamic performance without large modifications on the existing catenary system.

Place, publisher, year, edition, pages
CRC Press, 2016
Keyword
Finite element method, Mechanisms, Pantographs, Speed, System theory, Vehicles, Wave propagation, Catenary system, Current collection, Dynamic behaviours, Dynamic performance, Existing systems, Operating speed, Parametric study, Stiffness variations
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:kth:diva-174046 (URN)000385792300096 ()2-s2.0-84973621924 (Scopus ID)
Conference
24th Symposium of the International Association for Vehicle System Dynamics, IAVSD 2015; Graz; Austria; 17 August 2015 - 21 August 2015
Note

QC 20161118

Available from: 2015-09-28 Created: 2015-09-28 Last updated: 2017-10-09Bibliographically approved
3. Numerical study on pantograph raising and lowering in multi-pantograph operation
Open this publication in new window or tab >>Numerical study on pantograph raising and lowering in multi-pantograph operation
(English)In: The international Journal of railway technology, ISSN 2049-5358, E-ISSN 2053-602X, no 3Article in journal (Other academic) Submitted
Abstract [en]

Multi-pantograph operation is a convenient and efficient way to operate railway rolling stock, but the influence between the pantographs makes the system more sensitive and vulnerable than a single-pantograph system. When a train passes through special sections or in an emergency condition, it is necessary to lower one or all of the pantographs and then raise them up again. In these circumstances, the motion of the pantographs can introduce a sudden impact to the catenary that may change the pantograph configuration, then disrupting the dynamic stability. To address the dynamic performance during pantograph raising and lowering, a numerical study on multi-pantograph operation is carried out with help of a 3D pantograph-catenary finite element (FE) model under the conditions: up to three pantographs, various pantograph raising/lowering orders and different operating positions in a span. The results show that the leading pantograph is little influenced by the raising and lowering movement of any pantograph behind it. However, any trailing pantograph is significantly affected by any operation taking place ahead of it. The dynamic performance of the system depends on the pantograph spacing distance and the operational speed, but is little affected by the operating position in a span. To study auxiliary-pantograph operation where the leading pantograph works as an auxiliary pantograph, this paper shows how an optimal setting of the leading pantograph benefits the trailing pantograph and suggests specifying the speed where the leading pantograph gets into or out of service to avoid disruption.

Keyword
pantograph-catenary interaction, multi-pantograph operation, raising and lowering, auxiliary-pantograph operation
National Category
Mechanical Engineering Vehicle Engineering
Research subject
Vehicle and Maritime Engineering
Identifiers
urn:nbn:se:kth:diva-174047 (URN)
Conference
24th International Symposium on Dynamics of Vehicles on Roads and Tracks, Austria
Note

QS 2015

Available from: 2015-09-28 Created: 2015-09-28 Last updated: 2017-10-09Bibliographically approved

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