High-speed trains are well developing around the world due to their numerous advantages. Indeed, they are safe, sustainable, energy efficient, convenient and comfortable for passengers. Amongst the few drawbacks of such trains is the current collection mechanism, generally implementedas a pantograph in mechanical and electrical contact with the overhead line equipment, the catenary.
The Pantograph-Catenary (PAC) system is almost universally used for supplying the vital power to railway electrical trains. Despite offering a balance of cost effectiveness versus reliability, this important link in the railway power supply chain is also a listed cause of train failure faults. As train speeds increase, the reliability of power collection decreases; there is also a concomitant increase in the potential for accelerated component wear and failure to occur.
Mechanical models are very useful, for instance: to predict the displacement of the catenary, to predict the contact force, to estimate the component fatigue life, and to analyse the wear induced by the mechanical friction. There is also a need for electrical models to facilitate analysis of (amonst others): power transmission, arcing, and electromagnetic compatibility.
Much published work is available on the subject of PAC system modelling and simulation. The pantograph sub-model gene-
rally consists of 2 or 3 stages of mass-spring-damper components.
The catenary is a key sub-assembly and its structure is quite complex to model. This task has been carried out by many authors and numerical solutions have been proposed for an infinite or finite dimensional description of the catenary.
Typical PAC models are:
PACIFIC (PAntograph Catenary Interaction Framework for Intelligent Control) is a research project which is part-financed by the European Union, under the ERDF scheme, as part of the INTERREG IV A France (Channel) England cross-border European co-operation programme. The project is working towards the design and development of a CAD tool (Computer Aided Design), named SIMPAC, for the PAC system. This tool is expected to offer numerous possibilities for study and design facilities, of which one can quote:
– characterisation of contact strip according to: materials, thermal, mechanical, dynamics, and manufacturing points of view;
– mechanical structures and active testing of pantographs;
– diagnosis and detection of faults;
– actuators and control techniques;
– acoustic and aerodynamic studies;
– measurements and sensors.
SIMPAC will consist of a collection of simulation modules which are relative, on the one hand, to different mechanisms and components of the PAC; and on the other hand, to physical phenomena linked to its functioning.
Furthermore, particular attention will be paid to compliance with European standards in this domain; specifically standard EN-50318, as related to the PAC.
Thus SIMPAC is a software platform which will facilitate: the testing of new materials, the understanding of problems of wear and tear, validation of control-command strategies, and the evaluation of the effects of breakdowns; in summary, to improve and optimise PAC systems without having to resort to heavy and costly experimental studies, previously accomplished by means of a range of live tests or test runs.
In addition to the modelling and simulation work, a test-rig has been designed and built, as represented in the following picture.
Further work is under consideration to finalise SIMPAC, as well as the test-rig, in order to implement developed techniques; for instance, active control algorithms for regulation of the PAC Contact Force, such as: PID, LQR/LQG/LQI, LMI, Sliding mode, Neural and Fuzzy Control.
For further information, interested readers can visit the project website (http://www.u-picardie.fr/PACIFIC/i4) and are invited to the PACIFIC International Conference which will take place in Amiens (France) on 8th December 2011 (http://www.u-picardie.fr/PACIFIC).
Pr Ahmed RACHID – Université de Picardie Jules Verne (Fr) (rachid@u-picardie.fr)
Dr Simon WALTERS – University of Brighton (U.K.)
Dr Augustin MPANDA – ESIEE-Amiens (Fr)
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