Pantograph-catenary Contact Research Articles

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.

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.

Output feedback control of pantograph–catenary system with adaptive estimation of catenary parameters

With the increasing railway vehicle speed, pantograph–catenary (PAC) system has become an important part as its incidents still stand among the principal causes of railway traffic interruption. Indeed, when a rail vehicle moves, the pantograph should constantly press against the underside of the catenary. Nonetheless, it is difficult to get around the complexity of the physical interaction between the pantograph and the contact wire, which could deteriorate the quality of the electricity transfer. Thus, PAC system performances could dramatically be reduced because of bad current collection. Therefore, in this paper, we present an output feedback solution in order to design an active control of PAC system. The proposed solution is based on the backstepping control and an adaptive observer that estimates both the (unknown) catenary parameters and the system state. All synthesis steps are given and the closed-loop analysis shows asymptotic tracking behavior regardless of the time-varying catenary stiffness. Furthermore, a numerical example shows that the PAC contact can be regulated with desired effect.

An analysis method for correlation between catenary irregularities and pantograph-catenary contact force

Pantograph-catenary contact force provides the main basis for evaluation of current quality collection; however, the pantograph-catenary contact force is largely affected by the catenary irregularities. To analyze the correlated relationship between catenary irregularities and pantograph-catenary contact force, a method based on nonlinear auto-regressive with exogenous input (NARX) neural networks was developed. First, to collect the test data of catenary irregularities and contact force, the pantograph/catenary dynamics model was established and dynamic simulation was conducted using MATLAB/Simulink. Second, catenary irregularities were used as the input to NARX neural network and the contact force was determined as output of the NARX neural network, in which the neural network was trained by an improved training mechanism based on the regularization algorithm. The simulation results show that the testing error and correlation coefficient are 0.1100 and 0.8029, respectively, and the prediction accuracy is satisfactory. And the comparisons with other algorithms indicate the validity and superiority of the proposed approach.

Reliability analysis of TSG19-type pantograph based on time-dependent parameters

The aim of the present paper is to study the damage mechanism of the TSG19-type pantographs. Firstly, a rigid-flexible coupled dynamics model is established to predict the pantograph–catenary contact forces with different values of stiffness and damping. A three-dimensional finite element model of a pantograph is then built up to investigate the time history of the stress in a critical section of the pantograph. Dynamics simulations provide the contact forces for the finite element analysis, which the authors needed to extract the stress amplitude and the stress cycles for different values of stiffness and damping. Finally, a reliability model based on the Miner cumulative damage theory is proposed for the TSG19-type pantograph in which the stiffness and damping characteristics degenerate with time. The proposal also takes into account the pantograph life under a given reliability. The results show that the stress amplitude and stress cycles increase when so does the stiffness characteristic and damping decreases. In such way, the stiffness and the damping of the pantograph sets the operating life and the reliability of the component. Therefore, the reliability model appears as a useful tool in the design process of the TSG19-type pantograph since its parameters change with time.

Optimization of high-speed railway pantographs for improving pantograph-catenary contact

A crucial system for the operation of high-speed trains is the pantograph catenary interface as it is the sole responsible to deliver electrical power to the train. Being the catenary a stationary system with a long lifespan it is also less likely to be redesigned and upgraded than the pantographs that fit the train vehicles. This letter proposes an optimization procedure for the improvement of the contact quality between the pantograph and the catenary solely based on the redesign of the pantograph head suspension characteristics. A pantograph model is defined and validated against experimental dynamic characteristics of existing pantographs. An optimization strategy based on the use of a global optimization method, to find the vicinity of the optimal solution, followed by the use of a deterministic optimization algorithm, to fine tune the optimal solution, is applied here. The spring stiffness, damping characteristics and bow mass are the design variables used for the pantograph optimization. The objective of the optimal problem is the minimization of the standard deviation of the contact force history, which is the most important quantity to define the contact quality. The pantograph head suspension characteristics are allowed to vary within technological realistic limits. It is found that current high-speed railway pantographs have a limited potential for mechanical improvements, not exceeding 10%–15% on the decrease of the standard deviation of the contact force.

Influence of pantograph suspension characteristics on the contact quality with the catenary for high speed trains

In general the electrical energy is provided to the trainsets by the pantograph–catenary contact. The study of this system contributes to decrease the number of incidents and the maintenance and interoperability costs. Here a finite element method and a multibody dynamics approach are used to handle the catenary and the pantograph dynamics, implemented in a validated computational tool. The objective is to understand how pantograph parameters influence contact force characteristics and catenary uplift. The results provide indications on how the pantographs can be modified, in a design environment, or tuned to improve the performance of the overhead contact system.

Pantograph Dynamics and Control of Tilting Train

The modeling methodology of tilting train is studied. The vehicle and pantograph are considered as nonlinear multiple rigid body systems, and the catenary is modeled by FEM method. The electrical mechanical actuators for carbody and pantograph tilting control are also considered in the tilting train model. The method of on-line curving detection, filtering and control is adopted for the tilting train. The passive and active controls for the pantograph lateral motions during tilting train curve negotiation are analyzed. The pantograph guideway on top of the carbody is designed, and the control strategy for the pantograph active control is investigated. It is known that the pantograph lateral and vertical displacement and the fluctuation of pantograph-catenary contact force can be minimized by the use of active control.

Modelling Of Electromagnetic Emission FromCatenary-pantograph Sliding Contact.

This paper deals with the electromagnetic noise emission at radio frequencies (in the range 9 kHz to 1 GHz) into the neighbourhood from an electrical railway system. The study has been conceived in order to obtain a preliminary modelling of electromagnetic emissions due to dynamic interaction between catenary and pantograph which can be considered the source of the largest values of noise emission. The proposed sub-model of the electrical interaction between pantograph and catenary, implemented by using Matlab-Simulink®, is able to describe the complex phenomenon of pantograph current collection during both sliding and bouncing (in presence of electric arc). The electric arc, which is influenced by numerous and interactive variables, is not the only source of electromagnetic noise and it is demonstrated that also local mechanical irregularities, during real sliding phase without electric arc, can represent a strong source of noise emission. The model gives out, among many electrical variables, values of contact resistance which represent the interface between sliding contact model and line model. It also calculates the magnetic field surrounding the railway vehicle in function of the distance from the pantographcatenary contact.