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Numerical study on pantograph raising and lowering in multi-pantograph operation
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.ORCID iD: 0000-0001-7393-569X
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.ORCID iD: 0000-0002-8237-5847
Dep artment of Structural Engineering, NTNU Norwegian University of Science and Technology, Norway.
(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 [en]
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: urn:nbn:se:kth:diva-174047OAI: oai:DiVA.org:kth-174047DiVA: diva2:857301
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
In thesis
1. Numerical study on multi-pantograph railway operation at high speed
Open this publication in new window or tab >>Numerical study on multi-pantograph railway operation at high speed
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
numerical study, pantograph-catenary system, multi-pantograph operation, dynamic behaviour, high-speed operation
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Fordonsteknik
Identifiers
urn:nbn:se:kth:diva-173943 (URN)978-91-7595-683-1 (ISBN)
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
2. Measures to Enhance the Dynamic Performance of Railway Catenaries
Open this publication in new window or tab >>Measures to Enhance the Dynamic Performance of Railway Catenaries
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The pantograph-catenary system is used in railways to transfer electric power from infrastructure to trainset. As the pantograph slides against the catenary, the contact between the two surfaces is not stable due to stiffness variation, propagating wave and other environmental perturbation, especially at high speeds or in multi-pantograph operation. Heavy oscillation can result in poor power-transmission quality, electromagnetic interference, severe wear or even structural damage. So the pantograph-catenary dynamics has become one of the key issues which limits the operational speed and determines the maintenance cost. There are many types of catenary systems in Sweden, which are relatively soft and sensitive compared with the systems in other countries. They work well at low operational speed and have strict limitations to multi-pantograph operation. It is possible to achieve an operational speed of 350 km/h on newly-built high-speed lines, but there is still a large demand for higher operational speed and more capacity on the existing lines.

    Many researchers and engineers have made progress to improve its dynamic performance. From the research aspect, many numerical models have been built up to demonstrate the dynamics of the pantograph-catenary system and to unveil the key influencing factors. There have been many applications developed in recent years. Regarding the catenary, high-tensile loads on the catenary and low-stiffness-variation designs are widely used to improve the dynamic performance. Regarding the pantograph, aerodynamic-friendly designs and active-control technique contribute to the development of high-speed pantograph. But all these methods need not only large investment but long out-of-service. Considering the large scale and heavy service duty of the existing lines, it becomes almost impossible to completely upgrade the existing pantograph-catenary systems. So it is necessary to find practical and efficient methods to exploit the potentials of the existing systems to enhance their dynamic performances.

    This thesis investigates the dynamic behaviour of the Swedish pantograph-catenary systems and proposes methods for better usage. A numerical study on multi-pantograph operation is performed and the relationships between dynamic performance and some key parameters is established. By studying the multi-pantograph operation at short spacing distance, a method to use the leading pantograph as auxiliary pantograph is proposed to increase the operational speed on the soft catenary system. To ensure operational safety in abnormal conditions, numerical studies on pantograph raising/lowering processes and in catenary overlap sections are performed. By studying the influence of the lumped-mass on the dynamic performance, it shows that it is even possible to implement some artificial tuned-masses on the catenary for dynamic optimization.

Place, publisher, year, edition, pages
KTH Royal Institute of Technology, 2017. 42 p.
Series
TRITA-AVE, ISSN 1651-7660 ; 2017:60
National Category
Vehicle Engineering
Research subject
Vehicle and Maritime Engineering
Identifiers
urn:nbn:se:kth:diva-214464 (URN)978-91-7729-524-2 (ISBN)
Public defence
2017-10-18, F3, Lindstedtsvägen 26, stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20170915

Available from: 2017-09-15 Created: 2017-09-14 Last updated: 2017-09-15Bibliographically approved

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Liu, ZhendongStichel, Sebastian

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