Pantograph-catenary Interaction Research Articles

Influence of a high-speed train passing through a tunnel on pantograph aerodynamics and pantograph–catenary interaction

Aerodynamics of trains running inside tunnels change more significantly in comparison with open air scenarios. It has been confirmed that the lateral vibration as well as the aerodynamic drag of the trains is increased and the micro-pressure wave is produced at the tunnel exit when the trains are passing through tunnels. The aim of this article is to explore the impact of a high-speed train passing through a tunnel on the pantograph aerodynamics and the dynamic behavior of the pantograph–catenary interaction. The aerodynamic forces acting on the pantograph are investigated thoroughly by extensive numerical simulations as well as systematic field tests. To investigate the effects of the aerodynamic forces of pantograph on the quality of current collection, the numerical simulations of the pantograph–catenary dynamic interaction are conducted with our proposed model, taking into consideration the action of the aerodynamic uplift forces obtained by the numerical simulations on the pantograph. Then, a series of numerical simulations are also carried out to analyze the effects of the train speed and the blockage ratio on the aerodynamic uplift forces of the pantograph, on the contact forces, as well as on the displacement of the contact wire, while the train is passing through a tunnel. The results reveal that compared with the open air scenarios, the aerodynamic drag and uplift forces of the pantograph, the mean value of the contact force and the displacement level of the registration arm can considerably increase as the train runs inside a tunnel. Moreover, the statistical values of the contact forces and the displacement level of the contact wire become larger while the train is passing through the tunnel at different speeds. On the other hand, the quality of current collection decreases with the increasing of the blockage ratio.

A mathematical model for pantograph-catenary interaction

ABSTRACTModelling the interaction between the pantograph and the catenary is an active field due to the development of high-speed trains. In this article, a 3D mathematical model based on finite element method is proposed to study the dynamic behaviour of the pantograph–catenary system. The equations of motion for a beam element have been discretized to obtain the weak form associated to each element of the catenary. The pantograph–catenary dynamic interaction model is implemented as a numerical simulation tool. The proposed model is compared to the performance of a commercial 3D simulator and it is faced to the requirements of the European Standard EN50318.

An Extended Habedank’s Equation-Based EMTP Model of Pantograph Arcing Considering Pantograph-Catenary Interactions and Train Speeds

Pantograph arcing is a more and more common and prominent phenomenon in ac-electrified railway systems, especially with the increase of pantograph-catenary (PAC) interaction and train speed. In order to address this issue, an extended Habedank’s equation-based model, by means of the Electromagnetic Transients Program (EMTP), is presented to obtain equivalent modeling for pantograph arcing studies considering train speeds in this paper. First, the pantograph arcing phenomenon is investigated, such as transient mechanisms and influencing factors. Second, based on the features of existing and emerging pantograph arcing, Habedank’s arc equations are further derived and studied by improving voltage gradient and power dissipation. Next, due to the relationship among voltage gradient, power dissipation, and arc length, the maximum detachment interval law between pantograph and contact wire is obtained by establishing the finite-element model for PAC interaction, and the ultimate extended Habedank’s equation-based EMTP model of pantograph arcing considering different train speeds is acquired. Then, the related model parameters are discussed and determined. Finally, based on the China Beijing-Yizhuang HSR line model in EMTP, the arc characteristic differences considering loads under different parameter values are compared and analyzed. The comparison results illustrate that the proposed model can be feasible to determine and reveal the pantograph arcing characteristics and influences in the HSR system as well as the PAC contact loss problems.

Detection of Contact Wire Irregularities Using a Quadratic Time–Frequency Representation of the Pantograph–Catenary Contact Force

As for the rapid expansion of high-speed electrified railway industry, the current collection quality of electric locomotives becomes one of the crucial technical issues for the stable operation of trains. The key measurement index that can characterize the quality of current collection is the contact force between the catenary and pantograph on the locomotive roof. One of the major factors that affect the contact force is the contact wire irregularity, which appears to be very difficult to be measured or detected at present. In recent years, the frequency-domain indicators of the pantograph–catenary contact force (PCCF) have been gaining importance to address this issue. In this paper, a recent quadratic time–frequency distribution is selected to describe the time–frequency representation (TFR) of PCCF signal based on its nonstationarity. The Zhao–Atlas–Marks distribution (ZAMD) shows high time–frequency resolution and cross-term suppression for PCCF signals. To investigate the deterioration of the PCCF under contact wire irregularity, a pantograph–catenary interaction model is presented and verified. Some synthetic contact wire irregularities are generated and added to the interaction model. Based on the characteristics of quadratic TFRs of PCCF signals, a detection and localization approach for contact wire irregularity is proposed in this paper. The simulation and real-life experimental results indicate that the different forms of contact wire irregularity could be effectively detected and localized with meter accuracy using the ZAMD.

Parametric model for the simulation of the railway catenary system static equilibrium problem

Dynamic simulations of pantograph–catenary interaction are nowadays essential for improving the performance of railway locomotives, by achieving better current collection at higher speeds and lower wear of the collecting parts. The first step in performing these simulations is to compute the static equilibrium of the overhead line. The initial dropper lengths play an important role in hanging the contact wire at an appropriate height. From a classical point of view, if one wants to obtain the static equilibrium configuration of the system for different combinations of dropper lengths, one static problem must be solved for each combination of lengths, which involves a prohibitive computational cost. In this paper we propose a parametric model of the catenary, including the undeformed dropper lengths as extra-coordinates of the problem. This multidimensional problem is efficiently solved by means of the Proper Generalized Decomposition (PGD) technique, avoiding the curse of dimensionality issue. The capabilities and performance of the proposed method are shown by numerical examples.

Nonlinear analysis of wind-induced vibration of high-speed railway catenary and its influence on pantograph–catenary interaction

ABSTRACTThe wind-induced vibration of the high-speed catenary and the dynamic behaviour of the pantograph–catenary under stochastic wind field are firstly analysed. The catenary model is established based on nonlinear cable and truss elements, which can fully describe the nonlinearity of each wire and the initial configuration. The model of the aerodynamic forces acting on the messenger/contact wire is deduced by considering the effect of the vertical and horizontal fluctuating winds. The vertical and horizontal fluctuating winds are simulated by employing the Davenport and Panofsky spectrums, respectively. The aerodynamic coefficients of the contact/messenger wire are calculated through computational fluid dynamics. The wind-induced vibration response of catenary is analysed with different wind speeds and angles. Its frequency-domain characteristics are discussed using Auto Regression model. Finally, a pantograph model is introduced and the contact force of the pantograph–catenary under stochastic wind is studied. The results show that both the wind speed and the attack angle exert a significant effect on the wind-induced vibration. The existence of the groove on the contact wire cross-section leads to a significant change of the aerodynamic coefficient, which affects largely the aerodynamic forces applied on the catenary wires, as well as the vibration response. The vibration frequency with high spectral power mainly concentrates on the predominant frequency of the fluctuating wind and the natural frequency of catenary. The increase in the wind speed results in a significant deterioration of the current collection. The numerical example shows that a relatively stable current collection can be ensured when the wind flows at the relatively horizontal direction.

Identification of system damping in railway catenary wire systems from full-scale measurements

Damping is an important property in predicting the response of any civil or mechanical engineering structure, including railway catenary systems. Numerical models describing the pantograph–catenary interaction are dependent on a proper description of the structural damping for both systems to obtain accurate results. A proper description of the damping in different pantographs can easily be found in the literature. However, few studies have considered the damping properties in railway catenary systems even though such systems are considered to be lightly damped. The aim of this study was to identify the system damping of catenary sections by thoroughly analyse several recorded acceleration time series. These time series were sampled in several points on three different existing railway catenary systems, rendering a good description of the system damping in the frequency range of 0–20Hz. The covariance-driven stochastic subspace identification (Cov-SSI) method was used to analyse the time series, and Rayleigh coefficients were successfully identified for all three catenary sections.

Active Control of Contact Force for a Pantograph-Catenary System

The performance of the high speed trains depends critically on the quality of the contact in the pantograph-catenary interaction. Maintaining a constant contact force needs taking special measures and one of the methods is to utilize active control to optimize the contact force. A number of active control methods have been proposed in the past decade. However, the primary objective of these methods has been to reduce the variation of the contact force in the pantograph-catenary system, ignoring the effects of locomotive vibrations on pantograph-catenary dynamics. Motivated by the problems in active control of vibration in large scale structures, the author has developed a geometric framework specifically targeting the remote vibration suppression problem based only on local control action. It is the intention of the paper to demonstrate its potential in the active control of the pantograph-catenary interaction, aiming to minimize the variation of the contact force while simultaneously suppressing the vibration disturbance from the train. A numerical study is provided through the application to a simplified pantograph-catenary model.

Modelling and Active Control Designing of Trolleybus Catenary-Pantograph System

Abstract: This paper introduces the ‘Active Control of Trolleybus Current Collection Systems (ACTCCS)’ research project and a number of early key finding. The goals of this project are to address key operational issues of a trolleybuses catenary-pantograph system in terms of the loss of contact force that causes electrical arcing, power reduction and de-wirement. The causes of this loss of contact force and the proposed solution of an actively controlled pantograph are presented in this paper through dynamic modelling and simulation of trolleybuses catenary-pantograph interaction and the application of an LQI controller. The results show that loss of contact can be eliminated with a small actuation force and this can be traded off against catenary wire displacement.

Electromechanical interaction between carbon-based pantograph strip and copper contact wire: A heuristic wear model

Wear due to the sliding contact between a pantograph strip and the contact wire of a railway overhead line has three main contributions: (i) a mechanical one, due to friction, (ii) an electrical one, due to current flow at the contact area and (iii) that due to electrical arcs related to the power dissipated during arc generation. This paper presents a heuristic wear model for the contact wire which accounts for these contributions to wear. After a tuning phase with results obtained on a test rig to evaluate wear for the “pure copper contact wire—Kasperovski contact strip” coupling, the wear model is used in combination with a dynamic electromechanical model to estimate the amount of wear associated with pantograph–catenary interaction.

CaPaSIM statement of methods

In the present paper, the method for calculation of the dynamic pantograph–catenary interaction developed by the Royal Institute of Technology and the Swedish National Rail/Road administration (Trafikverket) is described and the results of the benchmark exercise are discussed. The method is based on the commercial Finite Element software ANSYS. The geometry of the catenary and pantograph is defined in a pre-processor, BARTRAD, developed by Trafikverket, and is automatically translated into an ANSYS model. Basically all types of catenary systems could be handled as well as different types of non-linearity. There are both 2D and 3D versions of the code existing. The results achieved in this first stage of the benchmark are well in line with the results from the other partners in the benchmark study

The results of the pantograph–catenary interaction benchmark

This paper describes the results of a voluntary benchmark initiative concerning the simulation of pantograph–catenary interaction, which was proposed and coordinated by Politecnico di Milano and participated by 10 research institutions established in 9 different countries across Europe and Asia. The aims of the benchmark are to assess the dispersion of results on the same simulation study cases, to demonstrate the accuracy of numerical methodologies and simulation models and to identify the best suited modelling approaches to study pantograph–catenary interaction. One static and three dynamic simulation cases were defined for a non-existing but realistic high-speed pantograph–catenary couple. These cases were run using 10 of the major simulation codes presently in use for the study of pantograph–catenary interaction, and the results are presented and critically discussed here. All input data required to run the study cases are also provided, allowing the use of this benchmark as a term of comparison for other simulation codes.

PantoCat statement of method

The pantograph–catenary dynamic interaction analysis program (PantoCat) addresses the need for a dynamic analysis code able to analyse models of the complete overhead energy collecting systems that include all mechanical details of the pantographs and the complete topology and structural details of the catenary. PantoCat is a code based on the finite element method, for the catenary, and multibody dynamics methods, for the pantograph, integrated via a co-simulation procedure. A contact model based on a penalty formulation is selected to represent the pantograph–catenary interaction. PantoCat enables models of catenaries with multiple sections, including their overlap, the operation of multiple pantographs and the use of any complex loading of the catenary or pantograph mechanical elements including aerodynamic effects. The models of the pantograph and catenary are fully spatial being simulated in tangential or curved tracks, with or without irregularities and perturbations. User-friendly interfaces facilitate the construction of the models while the post-processing facilities provide all quantities of interest of the system response according to the norms and industrial requirements.

PCaDA statement of methods

This paper describes the methods for the numerical simulation of pantograph–catenary interaction developed at Politecnico di Milano and implemented in the simulation software PCaDA (Pantograph–Catenary Dynamic Analysis). The paper also describes how these methods were applied in the pantograph–catenary interaction benchmark treated in this special issue and provides some evaluation of the results obtained using PCaDA in this benchmark.

Pantograph catenary dynamic optimisation based on advanced multibody and finite element co-simulation tools

This paper presents recent developments undertaken by SNCF Innovation & Research Department on numerical modelling of pantograph catenary interaction. It aims at describing an efficient co-simulation process between finite element (FE) and multibody (MB) modelling methods. FE catenary models are coupled with a full flexible MB representation with pneumatic actuation of pantograph. These advanced functionalities allow new kind of numerical analyses such as dynamic improvements based on innovative pneumatic suspensions or assessment of crash risks crossing areas that demonstrate the powerful capabilities of this computing approach.

Dynamic Performance Simulation of Overhead Contact System for over 350km/h High-Speed Rail

With full development of 350km/h high-speed rail network in China, further research in the key technology of 380km/h or higher super-speed rail system has become crucial. Applying the simulation of pantograph-catenary interaction based on infinite element method, this paper simulated the dynamic performance of pantograph-catenary system for high-tension overhead contact system at over 350km/h. The research findings showed that wave propagation speed can still serve as a brief computing method for the running speed within the range of 350-400km/h. When the running speed reaches 80% of the wave propagation speed or higher, the current-carrying quality of double-pantograph-catenaries system might not satisfy the standard of EN 50367 all the time.

Real-time catenary models for the hardware-in-the-loop simulation of the pantograph–catenary interaction

Hardware-in-the-loop (HIL) simulation is a promising technique to study the pantograph–catenary interaction problems by realising the interaction of a physical pantograph with a mathematical model of the overhead equipment (catenary). However, the computing power presently available on real-time CPUs only allows to run simplified models of the overhead equipment. Therefore, it is important to define catenary models that are suitable for real-time simulation and at the same time capable of accurately representing the dynamic behaviour of the catenary. In this paper, the use of a catenary model based on modal superposition is considered, and the effect of changing the number of modelled spans and the number of modal components allocated to the contact and messenger wires is investigated in view of finding the best model compatible with real-time simulation. Comparisons between HIL simulation results and line measurements are presented, to quantify the accuracy of the hybrid simulation method developed.

Performance evaluation and design optimization using differential evolutionary algorithm of the pantograph for the high-speed train

The global trend in the railway industry is the effort to increase the maximum speed and stability of a train. For an electric railway vehicle to meet this driving performance, stable electric power should be supplied by a catenary system. Various factors affect the current collection performance, most important of which is the dynamic characteristics of a pantograph. In this paper, the sensitivity analysis and design optimization of a pantograph for a high-speed train were conducted using a finite element method. The dynamic catenarypantograph interaction was analyzed by using the commercial finite element analysis software, SAMCEF. The pantograph was modeled as a three degrees of freedom mass-spring-damper system, and the pre-sag of the contact and messenger wire due to gravity was implemented. The span data of a high-speed line was applied in the analysis model. And the dynamic characteristics of the pantograph model were obtained by a performance test. The reliability of the simulation model was verified by comparing the analysis contact force results with the test data. By simulation, the mean contact force and its standard deviation etc. were evaluated, and then sensitivity of the pantograph was analyzed. Based on the sensitivity analysis results, the specification of the pantograph was optimized. In the optimization process, response surface analysis and differential evolutionary algorithm were applied to define the regressive function and to determine the optimum values for stable current collection performance. Finally, the improvement of the current collection performance was verified by comparing the optimum specification results with the original specification.

Numerical and Hardware-In-the-Loop Tools for the Design of Very High Speed Pantograph-Catenary Systems

To be competitive with other transport means for a wider distance range, high-speed trains need to increase their revenue service speed. Due to this need, improving the pantograph-catenary interaction to ensure appropriate current collection in spite of the increased dynamic effects and the larger electrical power required represents one of the most serious technical issues to be solved. The aim of this paper is to discuss the use of numerical and hybrid (hardware in the loop) simulation tools in the design of new overhead lines for a speed of 360 km/h. A validation of both simulation tools is performed using line measurements as a point of comparison; then the validated simulation approaches are used to quantitatively assess the effectiveness of some catenary design options.

Pantograph-catenary Dynamic Interaction for a Overhead Line Supported by Noise Barrier

Subject of the paper is a particular configuration of overhead line, in which noise barrier structure is used as supports of the catenary instead of standard poles. This configuration is foreseen in case the noise barrier position is in conflict with the poles location. If the catenary is supported by the noise barrier, the motion that the latter undergo due to wave pressure associated to train transit is transmitted to the overhead line, so that potentially it influences the interaction between the catenary itself and the pantograph of the passing train. The paper focuses on the influence of such peculiar configuration on the quality of the current collection of high speed pantograph, for single and double current collection. The study has been carried out first with an experimental investigation on the pressure distribution on noise barrier, both in wind tunnel and with in-field tests. Subsequently a numerical analysis of the dynamics of the barrier subjected to the wave pressure due to train transit has been carried out, and the output of such analysis has been used as input data for the simulation of the pantograph-dynamic interaction at different speeds and with front or rear pantograph in operation. Consideration of structural modifications was then highlighted, in order to reduce the influence on the contact loss percentage.