Pantograph Arcing Research Articles

Innovative Engineering Solutions for Short Neutral Section Maintenance Reduction in Railway Overhead Lines

This work addresses the challenges associated with the development of short neutral sections (SNS) for overhead lines of high-speed moving trains. A crucial function of a short neutral section is to provide electrical isolation between the different phases of AC traction. These sections are typically located in proximity to the traction substation and sectioning posts. The current SNS design presents several issues, including pantograph arcing, wear and tear of the overhead line system, and the need for manual rotation during periodic maintenance. To address these challenges TRIZ is used, a problem-solving methodology that leverages inventive principles to generate innovative solutions. The work outlines the use of several TRIZ tools and techniques, including the Interaction Matrix, Functional Analysis, Function-Body Diagram (FBD), Trimming, and the Contradiction Matrix [1]. With the application of these tools, the author presents several potential solutions for improving the SNS design to eliminate periodic maintenance and services. One proposed solution involves the use of a segmented overhead line system with an insulating cylinder-shaped discrete insulator to ensure smooth contact of the pantograph. Another solution involves the use of a twisted strip-based insulator to replace linear motion with rotating movement, eliminating the need for manual rotation. The work emphasizes the importance of considering various factors, such as design, material, wear rate, maintenance, and creepage distance, when evaluating the feasibility of these solutions. By leveraging TRIZ to generate innovative solutions, the author demonstrates the potential of this methodology to drive innovation and overcome complex challenges in the development of short neutral sections for high-speed rails.

Multiresolution Models of DC Traction Power Supply Systems With Reversible Substations

Reversible substations (RSs) permitting bidirectional power flows can recover the regenerative braking energy of trains in DC traction power supply systems (TPSSs), increasing the energy efficiency of railway systems. To predict their effects on system dynamics and energy savings, the paper develops multiresolution models (MRMs) to simulate the RS roles with different fidelities. A high‐resolution model for the transient simulation replicates a particular topology where a three‐level voltage source inverter is connected to the secondary winding of an existing 12‐pulse rectifier transformer and regulated to keep a constant DC voltage in the inverting mode. Furthermore, it can model the transient effects of pantograph‐to‐line arcing by inserting arc voltage profiles at the train’s input stage. To increase the computation speed in the long‐term energy flow simulation, a low‐resolution model simplifies the rectifiers into a series connection of a diode and a controlled voltage source depicting their nonlinear output characteristics and then places a DC voltage source in parallel to form a reverse path for braking power recovery. In addition, nonlinear conversion efficiencies are introduced to calculate energy flows across substations. The MRMs are tested based on a 1.5 kV DC TPSS and discussed alongside system dynamics under normal operation or pantograph arcing and the consistencies between different models. The RS using bidirectional voltage source converters only is additionally modelled to compare the technical performance of the two topologies in terms of system dynamics and energy efficiencies.

Mathematical Model of Pantograph Arc Based on Probability Distribution of Arc Parameters

Pantograph arc has become a potential hazard for the safe running of electric locomotive. It is essential to build an accurate mathematical model of pantograph arc for arc simulation. Pantograph arc experiments were carried out. And the probability distribution characteristics of arc parameters such as arc ignition moment, arc extinction moment and arc duration were analyzed. A mathematical model of pantograph arc was established. Firstly, Habedank model was selected as an initial mathematical model. The model parameters were optimized by using particle swarm optimization algorithm. Secondly, the initial mathematical model was preliminarily improved by using time-varying model parameters. Thirdly, taking into account the randomness of arc phenomenon, the model was further improved by adding a pulse function, and then the final mathematical model of pantograph arc was obtained. The pulse generation time and pulse width of the pulse function vary along with uniform distribution function and truncated normal distribution function, respectively. Finally, a simulation module of pantograph arc was designed with MATLAB software, and the effectiveness of the mathematical model was proved. The proposed model can describe the electrical characteristics of pantograph arc more accurately, and it can be used to further analyze the evolution of pantograph arc.

A Fast Prediction Method for the Electromagnetic Response of the LTE-R System Based on a PSO-BP Cascade Neural Network Model

In this paper, a fast prediction model of the electromagnetic response of the LTE-R (Long Term Evolution for Railway) communication system based on a cascade neural network is developed to quickly analyze the impact of pantograph arcing on the LTE-R system during vehicle operation. In order to obtain the coupling disturbance level of the LTE-R antenna port, this model uses the cascade neural network based on the PSO-BP (Particle Swarm Optimization of Back Propagation Neural Network) algorithm to quickly solve the coupling coefficient of the pantograph arcing measurement probe and the antenna port. A two-stage BP neural network model is used to train both the simulation data and measurement data, and the results are validated by field tests. Finally, the antenna port coupling interference is added to the LTE-R system to analyze the impact of pantograph arcing on the quality of communication transmission. Analysis and tests demonstrate that pantograph arcing can lead to an increase in the BLER of LTE-R systems at 400 MHz, affecting system performance and transmission efficiency.

Simulation and Verification of Effect of Arc Duration on Arc Temperature Based on COMSOL

The pantograph–catenary arc of urban rail has the characteristic of high temperature, which directly acts on the surface of the pantograph–catenary system, will seriously ablate pantograph and contact line, and affect the flow of the pantograph–catenary system. In this paper, based on MHD, a mathematical model of the arcing of urban rail pantograph–catenary system is established. COMSOL finite element software was used to simulate the arc temperature field of the pantograph–catenary arc. Through the temperature distribution cloud diagram and related images, the relationship between the arc central temperature, the duration, and the gap of the pantograph arc were studied. It is found that the arc temperature increases with the increase in arc duration when the arc gap is fixed. When the arc duration is fixed, the arc center temperature changes inversely with the increase in the arc gap. The feasibility of the simulation model is verified by the pantograph–catenary arc experiment platform. The research conclusion of this paper can provide a certain basis for the research of arc erosion on the surface of the pantograph–catenary system.

Research on the Characteristics of the Pantograph Arc and Analyzing its Influence on the ILS

In this article, a radiation model is proposed to estimate the emission of the pantograph arc. An improved least-square regression analysis method is given for studying the pantograph arc characteristics at various sites on electrified railways and at various train speeds. The radiation model and the improved least-square method were both validated using the test data. The impact of arc on the airport instrument landing system (ILS) was investigated using electromagnetic wave propagation theory and the signal-to-noise ratio requirement of the ILS. We deduced the position limit of the articulated neutral section (ANS) and verified it through experiments. This research provides a theoretical foundation and technological methodology for civil aviation and high-speed railway electromagnetic compatibility studies as well as helps for airport site selection and high-speed railway route planning.

Pantograph Arc Location Estimation Using Resonant Frequencies in DC Railway Power Systems

Pantograph arcing in electrified railway systems not only reduces the power collection quality of a locomotive but can also damage pantograph strips and overhead lines (OHLs). Most research detects pantograph-to-OHL arcs based on onboard voltage/current measurements, pantograph cameras, and so on. The use of onboard voltage/current data, though being cost-effective, rarely reflects arc locations along OHLs. This article develops an arc positioning method, which matches the position-dependent resonant frequency (RF) of an OHL with the RF extracted from voltage measurements in a pantograph arc event. A particular 20-km DC railway line supplied by two substations is first modelled in MATLAB/Simulink, with the model effectiveness being assessed based on voltage measurements in an arc event. Then, the OHL-related RFs estimated by the model are validated by the Tableau formula and discussed alongside impacts on RFs based on line models, locomotive locations, and line lengths. These evaluations permit the generation of an RF curve that links OHL-related RFs with arc locations. The arc positioning method is tested based on the pantograph arc events presumed at various positions along the 20-km line, showing errors within 0.2 km at certain locations. The ability to determine arc locations will permit periodic inspections to be performed on the determined line sections.

Fast Prediction Model of Coupling Coefficient Between Pantograph Arcing and GSM-R Antenna

In this article, a fast prediction model based on machine learning is established to predict the coupling coefficient between pantograph arcing, and GSM-R antenna. Compared with the method of solving coupling coefficient based on electromagnetic simulation, the prediction model established in this article can not only ensure the accuracy of coupling coefficient, but also avoid a lot of repeated simulation, and reduce the simulation time. First, the data set is constructed by Latin hypercube sampling. Then, by analyzing the distribution characteristics of the data set, the Radial Based Function (RBF), and Generalized Regression Neural Network (GRNN) are selected for modeling. Furthermore, in order to improve the prediction precision, Modular Neural Network (MNN) is introduced, and the collaborative integration strategy of segmented prediction is proposed, which realizes the complementary advantages of RBF, and GRNN, and completes the construction of prediction model. Finally, the precision, and validity of the prediction model is verified by the analysis of the prediction results, relative prediction deviation, and other related parameters.

Analysis of Propagation Characteristics of Electromagnetic Disturbance from the Off‐Line of Pantograph‐Catenary in High‐Speed Railway Viaducts

Pantograph arcing caused by Off-line of pantograph-catenary (OLPC) will generate Electromagnetic disturbance (EMD), which will affect train control system and communication system. This paper proposes a simplified model of the train and pantograph to investigate propagation characteristics of EMD from OLPC in the viaduct scenario, containing attenuation law in transverse and longitudinal directions. As a result, the electric field strength of EMD from OLPC increases with distance in transverse direction from 10m to 30m in the viaduct scenario, which is different from the ground scenario. The fitting formulas are found to research the attenuation law at different frequency points. We get the conclusion that the limit and measurement distance is not applicable for the viaduct scenario in current standard. To prove this, measurement in the viaduct scenario is completed, and the plausible evidence to explain the result is discussed. These results are useful in the measurement of radiated emissions, on-board equipment layout and the research of standard in high-speed railway.

Influence of the Crosswind on the Pantograph Arcing Dynamics

As one of the most important electrified railway components, the pantograph-catenary (PC) system plays a key role in the energy transfer for the train through the sliding electric contact. However, the performance of the PC system is severely limited by pantograph arcing, and the study on the dynamic characteristics of pantograph arcing is still far away from satisfactory. In this article, a magnetohydrodynamic (MHD) model of pantograph arcing is first established, which focused on the impact of crosswind as well as the input current on the arcing dynamics. Once the model was validated by laboratory experiment, the influences of the crosswind and input current on the arc temperature and voltage are studied in detail. Two parameters, namely the diameter of the catenary and the gap distance between the pantograph strip and the catenary, were varied to see what effects that might have. An interesting periodic phenomenon for both the temperature and voltage fall has been found, which was explained based on the Karman vortex street of fluid theory.

Application of GWO-SVM Algorithm in Arc Detection of Pantograph

High-speed train will produce pantograph arc during the driving process, which is harmful to pantograph-catenary system. In order to reduce pantograph-catenary system damage, a method based on Gray Wolf algorithm to optimize the binary Support Vector Machine classifier to identify pantograph arc is proposed. In this article, 5 groups of pantograph current experiments under different conditions are carried out, and the current data in the pantograph-catenary system under different conditions are measured. The current data state obtained from the pantograph experiments is divided into normal current state and arc current state. Select the mean value, variance, standard deviation, mean value of the first-order difference, and mean value of the second-order difference of the current data as the characteristic value of the pantograph current, and calculate the contribution rate of each characteristic value at the same time, then the current eigenvalue data with a high contribution rate is used as a training sample for learning and recognition through the classifier optimized by Gray Wolf algorithm. The experimental results show that the Gray Wolf optimization algorithm can quickly and accurately identify the pantograph arc, and the classification model obtained is more accurate than the commonly used optimization algorithms such as genetic algorithm and particle swarm. In addition, an engineering implementation of on-line identification of pantograph arc based on industrial computer is proposed.

Pantograph Arc Detection of Urban Rail Based on Photoelectric Conversion Mechanism

According to the solar-blind characteristic of the pantograph arc spectrum distribution, an arc detection method based on the photoelectric conversion mechanism for urban rail was proposed, and the design of each part of the arcing detection system was completed. Through the analysis of arc spectral distribution, the 275-285 nm band was determined as the detection characteristic waveband. The optical acquisition system located on the roof of the train collects the arc characteristic light and transmits it to the photoelectric conversion module, which converts the received optical signal into the corresponding current signal linearly. After amplification, comparison and screening in this module, the optical signal is sent to the data processing module for output display. Finally, a field test conducted on an urban rail transit line shows that this arc detection system can effectively detect the pantograph arc phenomenon and reflect the arc intensity linearly avoiding the influence from natural light, train load and train running direction.

Direction Finding Techniques in Reactive Near Field of Impulsive Electromagnetic Noise Source Aiming at Pantograph Arcing Localization

Pantograph arcing is well known to have several detrimental effects, including electromagnetic compatibility issues. In this paper, we proposed to use direction finding techniques utilizing only two magnetic field components to determine the location of the arcing occurrence independent of weather conditions and with low computational load. Two techniques suitable for impulsive electromagnetic noise in reactive near field are presented. One is well known in the literature and another, which is based on the absolute value of the Poynting vector, is proposed here for the first time. Experiments with an electrostatic discharge gun in a semi-anechoic chamber were used to validate the new technique and to estimate the accuracy of both for pantograph arcing localization.

Suppression of Cable Overvoltage in a High-Speed Electric Multiple Units System

There are two cases that can cause cable overvoltage in a high-speed electric multiple units (EMU) system: one is the seriously rusty rail; the other is pantograph arcing, especially when the train passes through the phase separations. Both cases can endanger the normal operation of the EMU. In this paper, a full analysis is given on the mechanism of the electromagnetic interference, corresponding to the conducted and radiated interference. First, the actual circumstances in which the two kinds of interferences generate are described and the equivalent circuit model is established. Then, the two kinds of interference are analyzed and the induced overvoltage is calculated by means of finite-difference time domain method and piecewise-line technique. Next, based on the analysis mentioned above, a specific transient voltage suppressor (TVS) is proposed to be applied at the terminal of a cable in the train. Finally, the results of theoretical calculation, simulation by Computer Simulation Technology, and measurement are obtained and compared, among which a good agreement is achieved. Thus, the validity of the equivalent circuit model and the suppression effect of the TVS on overvoltage excited by conducted and radiated interference are verified.

Longitudinal Propagation Characteristic of Pantograph Arcing Electromagnetic Emission With High-Speed Train Passing the Articulated Neutral Section

Based on the analysis of the practical measurement data of H-field values at three different sites along the longitudinal direction of the railway, this paper proposes an aerial catenary nonuniform transmission line model to predict longitudinal propagation characteristic of pantograph arcing electromagnetic (EM). According to the theory of EM field, EM emission field value measured at articulated neutral section (ANS) site is converted into the initial current of the contact wire. With the initial current, the current distribution on the contact wire and the EM field distribution along the railway when pantograph slid the ANS could be obtained by the proposed model. The validity of the proposed model is verified by the consistency of the theoretical results and the practical measurement at 0.5 MHz, which is the frequency point of the nondirectional radio beacon (NDB).

A Supercapacitor-Based Method to Mitigate Overvoltage and Recycle the Energy of Pantograph Arcing in the High Speed Railway

The pantograph arcing phenomenon may shorten the service life of a pantograph and even destroy onboard devices and instruments, due to the irregular motions of the train and the intermittent line–pantograph disconnection. This paper points out that abrupt inductive energy from the magnetizing inductance of the traction transformer can lead to an electromagnetic transient process with unexpected overvoltage across it. Further, a supercapacitor-based power electronic system is proposed, which can not only redirect the inductive energy to the supercapacitor pack through bidirectional converters but also mitigate the overvoltage across the main electrical equipment when pantograph arcing occurs. Simulation results show the overvoltage could be reduced and the energy stored in the supercapacitor which could also be used to provide energy for sensors or other devices.

Research on Electromagnetic Transient Processes of Long Marshalling High-Speed Train Passing Articulated Split-Phase Region

When a long marshaling high-speed train (HST) with two raised pantographs passes an articulated split-phase region, there will be eight electromagnetic transient processes along with pantograph arcing. These transients cause over-voltage in the train body (TB), which can have a negative effect on the train's electronic equipment. In view of this issue, this paper closely analyzes the different transient processes generated by an HST passing a split-phase region. The analysis focuses on identifying the root causes and influencing factors relating to each transient process, examining, in particular, the capacitive coupling between TB and overhead contact system and the capacitive coupling between TB and the neutral wire. The results of this analysis are then used to establish Bergeron mathematical models that can be used to derive and study the eight independent transient processes. This leads to the generation of more detailed models that can be used to accurately simulate the phenomenon according to different variables, such as the phase difference of feeders, with Electromagnetic Transients Program (EMTP) software. The analysis results demonstrate that the hazardous PH over-voltages and TB over-voltages are easily generated. This paper concludes by drawing upon the simulation results to discuss possible over-voltage suppression measures, such as phase and grounding optimization for the pantograph and TB.

Modeling and simulation of arc and contact wire molten pool behavior during pantograph lowering process

Contact wire is an essential part of traction power supply system in the electrified railway, which on the one hand transmits the electrical energy, and on the other hand plays as a smooth track for the current collection strip. In the daily operation of the electrified train maintenance, the contact wire suffers from the arcing ablation during the pantograph lowering process. Potential contact wire breakdown might take place. In this paper, the surface erosion of the contact wire by the pantograph arcing was studied numerically. A multi-physical model dedicated to the contact wire erosion issues was established, with the process of heat transfer, phase transition, and liquid metal flow taken into account. Characteristics of the surface erosion, the temperature field as well as the flow field under different current conditions were studied respectively. Particularly, the Marangoni effects on molten pool evolutions were examined, which could have a significant influence on the final erosion characteristics. This work might be helpful for the further understanding of the basic physical process of the contact wire erosion by the pantograph arcing, and as well as providing a meaningful reference for the performance improvement of the current collection system.

Influence Study on Electric Vehicle-traction Network System Considering Pantograph Arcing

This article analyzes the influence of pantograph arcing phenomenon on the electrical quantity which is related equipment of traction power supply system. The Mayer arc model was improved by taking into account arc dissipation power, arc diameter, transverse blowing arc and so on, based on this, modeling was performed, the traction power supply system such as AT doublewire traction network model and CRH3 EMU load model was described mathematically later on, and simulation analysis was ultimately achieved using MATLAB/Simulink software. The study results show that the pantograph arcing phenomenon causes the harmonic components that are the voltage and current of the traction network to increase, at the same time, making the performance indexes of the DC-side voltage of the CRH3 EMU rectifier to change.

Arc Erosion Characteristics of Cu-Impregnated Carbon Materials Used for Current Collection in High-Speed Railways

Currently, great attention has been paid to the fast development of high-speed railways all over the world. With an increment of running speed, pantograph arcing has become a significant issue, which can threaten the lifespan and service performance of pantograph strip materials severely. Cu-impregnated carbon strip is one of the most widely used strip materials in high-speed railways, while its arc erosion characteristics and mechanisms are still in absence. In this paper, the arc erosion characteristics of Cu-impregnated carbon materials were experimentally studied. The variations in voltage waveforms between electrodes with time were recorded, and the evolution of the temperature distribution of strip was obtained by a thermal infrared imager. The arc erosion surface was examined using a digital camera, a scanning electron microscopy, and energy dispersive X-ray spectroscopy to assess the macroscopic and microscopic morphologies, as well as elemental distributions in or around the arc erosion crater. An interesting arc crater-centered multicolored subarea on the strip surface was found, which was explained from the aspects of the effect of arc-induced temperature and formation of copper oxide film. The arc erosion crater consisted of several overlapped erosion pits, and the mechanism of the pits was understood from the unique microstructure and physical properties of carbon phase and copper phase in the materials. Finally, the formation of spherical copper particles and cracks was illustrated, and their influences on the sliding wear and friction process were discussed.