Pantograph Catenary Research Articles

Pantograph Catenary Performance Detection of Energy High-Speed Train Based on Machine Vision

With the rapid development of high-speed rail in China, addressing the issue of safety assurance during the operation of the train is very important. A very important part of a train’s power supply system is the pantograph and catenary system, which consists of a pantograph and a catenary. Failure of the pantograph-catenary system can cause significant damage to the normal operation of the train. The dynamic performance of the pantograph-catheter system must be detected in real time during the operation of the train. This paper is based on the study and analysis of pantograph-catheter dynamic performance parameters and developed a system for real-time detection of pantograph-catheter dynamic performance parameters based on a car visual system. The results are as follows: based on this detection method, the visual error is low and the accuracy is high. The machine-based directional height detection module developed in this paper has a good detection effect and high test accuracy; the arcing detection module designed in this paper can effectively detect the arcing and store the arcing pictures and can display the duration of single arcing and the arcing rate of the section in real-time. The practical application effect is good. The results show that the focal length of the camera lens is 16 mm, and the error of the machine vision system is low. The system designed in this paper may make a great contribution to the operation condition monitoring and fault diagnosis of the pantograph-catenary system of a high-speed train in the future.

Analysis of the pantograph’s mass distribution affecting the contact quality in high-speed railway

ABSTRACT The pantograph–catenary system is an essential device, transmitting electric energy to high-speed trains. The sliding contact quality between the collector strip and the contact wire must be strictly required, keeping the good current collection quality. In this work, the displacements of two independent tension wires are described by the Fourier sine-series expansions separately. The Lagrange equation of the second kind is used to establish the dynamic equation of the catenary, which is solved by the central difference method. A multi-rigid body dynamics theory based on the relative coordinates is adopted, describing the dynamic behaviour of the pantograph. Three types of mass distribution strategies applied to the main structure of the pantograph are discussed. The mass distribution of the main structure has a large effect on the pantograph–catenary interaction, and the maximum reduction ratio of the standard deviation (STD) of the dynamic contact force reaches −35.62%, which is significant for the pantograph’s structural optimization in high-speed railways.

The evolution law of the pantograph–catenary arc with the multi-stress coupled force analysis under the sub-atmospheric pressure strong-airflow condition

As the unique power entrance, the pantograph–catenary plays a vital role in providing traction power for high-speed railways. Along with the operational velocity of trains constantly increasing, the poor contact between the contact wire and the pantograph strip happens frequently due to the “rigid point” existing on the contact wire, forming the “off-line” phenomenon. The off-line phenomenon is normally accompanied by the pantograph–catenary arc occurring, which seriously threatens the safety of the power supply for the high-speed train. Nowadays, as some railways have been built in remote places at high altitude, the motion characteristics of the pantograph–catenary arc under the sub-atmospheric pressure with strong airflow are extremely different from the case under normal pressure. Herein, a pantograph–catenary arc experimental platform is built for observing the evolutionary process of the arc under the sub-atmospheric pressure strong-airflow condition. The impact brought from different air pressures and airflows on the arc is analyzed, as the experimental results show that the pantograph–catenary arc has different motion characteristics when the arcing process is at different stages. To further explore the reason resulting in the varying motion characteristics of the arc, a multi-stress coupled force analysis model is established, with the consideration of the influence of air pressure, wind load, thermal buoyancy, air resistance, arc self-magnetism, etc. From the perspective of force acting on the arc, the arc formation mechanism at the development evolutionary stages is investigated under sub-atmospheric pressure strong-airflow conditions, which lays a theoretical foundation for effectively restraining the pantograph–catenary arc.

Inception module and deep residual shrinkage network-based arc fault detection method for pantograph–catenary systems

Inception module and deep residual shrinkage network-based arc fault detection method for pantograph–catenary systems

Study on electric spark discharge between pantograph and catenary in electrified railway

The electric spark caused by pantograph-catenary (PC) electrical contact failure happens frequently, it is a kind of arcing phenomenon which can severely affect the current collection of PC. The theoretical analysis and modelling of PC electric spark are tried. First, the contact spots between PC and their temperature rise are analysed and derived based on the classical electrical contact theory, respectively. The mechanism of spark discharge is revealed through the analysis of PC voltage difference, and the spark discharge model is proposed combining with the spot temperature rise formula and spark discharge mechanism. Then, in order to obtain some key parameters in an electric spark discharge model, such as contact force and contact current, the structure model of PC and the circuit model of vehicle-grid are established for the calculation of the spark rate in PC. Finally, the spark rate is calculated and analysed under the different parameters in PC system. The calculation results are verified by the experiment results. Through the presentation of the correlation of electric spark discharge and factors, such as contact force, contact current and material of PC, this study can support the assessment of electrical contact quality in the PC system in future study.

Study on the Modeling and Suppression of Arcing Generated by Articulated Split-Zone Insulator in Electrified Railways

In electrified railways, pantograph–catenary (PC) arc frequently occurs in the process of train passing through split-zone insulator, which threatens the current collection of PC and operation of electric multiple units (EMUs). So far, there have been a few studies on the analysis and modeling of the PC arc on split-zone insulator. It is noting that this research is different from that of split-phase region. This article first analyzes the dynamic variation process of PC distance as EMUs pass the insulator and deduces the formula, which can reflect the PC arc length variation according to the specific mechanical structure of insulator. Then, a black-box arc model of split-zone insulator is proposed. Next, a vehicle-to-grid model of the EMUs that contains the arc model of split-zone insulator is established to simulate and analyze the characteristics of the PC arc on split-zone insulator. Furthermore, the proposed arc model in this article is verified by comparing the simulated arc characteristic waveforms with the measured results. Finally, a sensitivity analysis of the arc model under different lifting angles of the contact wire is carried out in order to analyze the suppression of PC arc on split-zone insulator.

Assessment of the Current Collection Quality of Pantograph–Catenary With Contact Line Height Variability in Electric Railways

The numerical tools are widely used to facilitate the design of the railway catenary. Only radical results are obtained as the current assessment is generally performed without any practical errors. In this article, the most common error, the contact line height variability, is appropriately included in evaluating the current collection quality. Based on the real-life contact line height data collected from a high-speed network, the heights of the key points in the contact line are extracted, of which the pointwise stochastics is represented by the power spectrum density (PSD) function. Random samples are generated by the inverse Fourier transform based on the Monte Carlo method. An advanced initialization procedure is presented to properly include the contact line height variability in the initial configuration. A stochastic analysis with a high cutoff frequency is performed to evaluate a double pantograph–catenary system’s current collection quality. Unlike the deterministic result obtained by the perfect design data, the contact line height variability causes uncertainty. The present analysis method indicates some risks of safety accident and contact loss that the traditional simulation cannot capture with ideal design data or low cutoff frequency.

The Thermal Dissipation Characteristics Analysis of the Rotatable Circular Pantograph–Catenary System

As the unique power entrance of high-speed trains, the pantograph–catenary system (PCS) plays the critical role of power transmission for high-speed trains. The pantograph achieves the electrical power based on the sliding electrical contact between the pantograph strip and the high-voltage contact line. However, when the environmental temperature is relatively low especially during the winter, the contact line is covered by ice or snow easily. The ice or snow adhering on the surface of contact line may lead to poor electrical contact between the pantograph strip and the contact line, which may trigger the pantograph–catenary arc appearing. Accompanying with mechanic shock and friction heat, the off-line arc may deteriorate the quality of power transmission and meanwhile erode the contacting surface of the pantograph strip and the contact line to some extent. In order to solve this technique bottleneck, a novel rotatable circular-shape pantograph strip is proposed to improve the overall performance of the traditional pantograph strip. Compared with the traditional strip, the circular pantograph strip owns many advantages, such as less friction, better thermal dissipation, and better shock resistance. The thermal dissipation performance of both the traditional and circular pantograph strip is evaluated in this article, with the consideration of suffering off-line arc under the icing conditions.

Crosswind Effects on Current Collection Quality of Railway Pantograph–Catenary: A Case Study in Chengdu–Chongqing Passenger Special Line

As a common disturbance to the railway pantograph–catenary system, the crosswind usually deteriorates the current collection quality and threats to operational safety. The main topic of this article is to evaluate the effect of crosswind on the interaction performance of pantograph–catenary considering the aerodynamic forces acting on both the pantograph and catenary. The pantograph–catenary system of the Chengdu–Chongqing passenger special line is adopted as the analysis object. The absolute nodal coordinate formulation (ANCF) is employed to model the catenary. The numerical accuracy is validated via the comparison with the field measurement data collected from an inspection vehicle operating at 378 km/h. According to the quasi-steady theory, the wind load acting on the catenary is derived. Computational fluid dynamics (CFD) is employed to calculate the lift and drag forces acting on each component of the pantograph, which are used to derive the equivalent aerodynamic force that can be applied in the lumped-mass model. A special spatial grid is defined for the pantograph–catenary system to generate the fluctuating wind field based on the empirical spectrum. The simulation results indicate that the pantograph–catenary system of Chengdu–Chongqing passenger special railway has an acceptable performance with a crosswind speed of 20 m/s. However, when the crosswind increases up to 30 m/s, some contact force statistics exceed the safety threshold with a turbulence intensity of more than 17%. Through the analysis of the operational safety, it is found that the contact wire always works within the safety range of the pantograph head with a crosswind speed of 30 m/s. However, some safety issues can be seen from the maximum uplift of the pantograph head with a turbulence intensity of more than 21%.

Characteristics and GWO–ANN Model Based on Prior Knowledge for Contact Resistance in a Pantograph–Catenary

The current-collection performance of a pantograph–catenary directly influences the safe operation of high-speed electric locomotives. The contact resistance is a primary indicator to evaluate the stability and reliability of the current-collection performance. The effects of sliding speed and electric current on the contact resistance between the carbon strip and the contact wire under a dynamic pressure load were studied using a sliding electrical contact testing machine. To predict the contact resistance under various working conditions, an artificial neural network (ANN) regression model, based on the gray wolf optimizer (GWO) algorithm and prior knowledge, was developed. The GWO algorithm was used to optimize the initial biases and weights of the ANN to avoid becoming trapped in local optima. The performance of the GWO–ANN can be further enhanced by the use of prior knowledge. The results showed that the GWO–ANN model that included prior knowledge can be introduced as a new technique for estimating the contact resistance in pantograph–catenary systems.

Intelligent Contact Force Regulation of Pantograph–Catenary Based on Novel Type-Reduction Technology

In this paper, an intelligent control scheme is proposed to suppress vibrations between the pantograph and the catenary by regulating the contact force to a reference value, thereby achieving stable current collection. In order to reduce the computational cost, an interval Type-2 adaptive fuzzy logic control with the Moradi–Zirhohi–Lin type reduction method is applied to deal with model uncertainties and exterior interference. Based on a simplified pantograph–catenary system model, the comparative simulation results show that variation of the contact force can be attenuated and variation disturbances can be repressed simultaneously. Furthermore, in terms of computational burden, the proposed type reduction method outperforms other type reduction methods.

Study of Time-Frequency Characteristics of Contact Force Signal and Parameter Sensitivity of Catenary of High-Speed Railway

With the increasing train speed, catenary fluctuation and pantograph vibration are intensified, the pantograph–catenary contact force (PCCF) at the dropper point increases, and the current collection quality of pantograph–catenary contact deteriorates. This study performs the location analysis of the PCCF characteristics based on the simulation method to reduce the PCCF value at the dropper point. First, the key wavelength component and the corresponding amplitude component (ac) of the PCCF at the dropper point were located using the time-frequency representation, which is the continuous wavelet transform (CWT). It was found that the PCCF signal at each dropper point considered the dropper spacing wavelength (DW) and span wavelength (SW) as the time-frequency characteristics (TFC) components; however, its contribution to the current collection quality for each dropper point was different. Second, the ac change rule of the DW and SW was analyzed by changing the tension and linear density of the catenary. Third, the sensitivity analysis method was used to quantitatively analyze the relationship between the catenary design parameters and the ac of the PCCF at the dropper point. Moreover, the quantitative analysis of PCCF was conducted based on the positioning analysis. It is concluded that the influence of catenary tension and linear density of messenger wire on the key ac is significant. Finally, the catenary structure was optimized via the parameter sensitivity coefficient when the train was running at 450 km/h speed. The results show that the current collecting quality of pantograph–catenary is improved effectively.

Reduced Track–Train–Pantograph–Catenary Interaction Model for Dynamic Analysis of Existing Overheads in Over-Design-Speed Operation

Reduced Track–Train–Pantograph–Catenary Interaction Model for Dynamic Analysis of Existing Overheads in Over-Design-Speed Operation

A simulation investigation on the influence of pantograph crack defect on graphite contact strip wear

The pantograph commonly suffers from two types of defects in metro-rail transit: abnormal wear and crack defect. It very often suffers both, thereby increasing the risks posed to train-operation safety. Previous research has not considered the influence of pantograph cracks on contact strip wear. This study establishes a pantograph–catenary dynamics model with crack defect to investigate the influencing pattern of crack defect, as well as the catenary arrangement form under cracked condition on graphite contact strip wear. Results show that the presence of pantograph cracks accelerates the wear rate and induces the eccentric wear and marginal wear problem. An 8 m span and a splayed arrangement form of the pull-out value are preferred.

Parameter identification for current–temperature relationship of contact wire under natural convection

The current–temperature relationship of contact wire in high-speed railways is the key to the design of pantograph–catenary system and operational planning of electrified locomotives. The traditional researches on the current–temperature relationship of bare overhead conductors and model parameters mainly focus on aluminum conductor steel reinforced (ACSR), while the description of the heat balance process of contact wire is relatively lacking. In this paper, by optimizing the features of the existing models, an electro-thermal coupling (ETC) model is established to describe the current–temperature relationship under different convection conditions. For the unknown parameters in this model, a parameter identification method based on the nonlinear primal–dual interior point algorithm is applied. The effectiveness of the parameter identification method and the ETC model is verified by the current–temperature experiment of contact wire under different current levels. The experimental results show that the root mean square error of the ETC model using identified parameters is only 1.22%, which demonstrates that the parameter identification method can effectively obtain the model parameters under natural convection. On this basis, a comparison shows that the root mean square error of the ETC model is 6.81% lower than that of the IEEE model, which demonstrates that the ETC model can describe the current–temperature relationship of contact wire under natural convection more accurately after parameter identification.

Analysis of collision dynamics of lifting the pantograph during vehicle operation

It is a practical engineering problem to lift the pantograph during train operation. In this paper, a pantograph-catenary (PAC) model is established, which can realize pantograph lifting during train operation. In this model, the contact model between contact piece and contact wire is established using the polygon contact model (PCM). The PAC collision test rig is established, and the simulation model at low speed is verified by comparing the contact force and vertical acceleration of contact piece obtained from simulation and test. The factors influencing the process of pantograph lifting are analyzed. The simulation results show that the position where the dropper and contact wire are connected is the most disadvantageous position for pantograph lifting. The maximum impact force increases with the increase of pantograph lifting speed, and the relationship between them is linear. In addition, if the influence of aerodynamic force is not considered, the running speed of vehicle will not affect the pantograph lifting process.

A Dynamic Model for the Study and Simulation of the Pantograph–Rigid Catenary Interaction with an Overlapping Span

In this paper, the authors present a mathematical and engineering model to optimally calculate the dynamic equation on the pantograph–catenary interaction when considering a rigid catenary with an overlapping span. The model starts from well-known methods adapted to the special features of rigid catenary. As a result, an algorithm for the integration of a dynamic equation based on explicit methods is provided. Moreover, from this algorithm, a reliable, efficient, and user-friendly software tool called RICATI is developed in order to approach the model to railway-based companies. The results show the usefulness of an application. such as RICATI, to check the behavior of the configuration initially established for a catenary, allowing solutions to be obtained for the problems encountered when simulating the passage of the pantograph (or pantographs), not only for the overlapping span but also for the entire catenary. That encourages us to continue future works.

Structural Health Monitoring Method of Pantograph–Catenary System Based on Strain Response Inversion

Pantograph-catenary system provides electric energy for the subway lines; its health status is essential to the serviceability of the vehicle. In this study, a real-time structural health monitoring method based on strain response inversion is proposed to calculate the magnitude and position of the dynamic contact force between the catenary and pantograph. The measurement principle, calibration, and installation detail of the fiber Bragg grating (FBG) sensors are also presented in this article. Putting this monitoring system in use, an application example of a subway with a rigid overhead catenary is given to demonstrate its performance. The pantograph was monitored and analyzed, running underground at a maximum speed of 80 km/h. The results show that the strain response inversion method has high measurement accuracy, good data consistency, and flexibility on sensor installation. It can accurately calculate the magnitude and location of the contact force exerted on the pantograph.

Identification of short-wavelength contact wire irregularities in electrified railway pantograph–catenary system

The effect of two common types of short-wavelength irregularities (local imperfections and periodic short-wavelength irregularities) of the railway catenary on the pantograph–catenary interaction performance are studied and their potential identification approaches are explored in this paper. The analysis of the intrinsic mode functions of panhead acceleration indicates that the effect of local imperfection can be reflected in the high-order deformation mode of the contact wire. The cut-off frequency is suggested to cover the wavelength smaller than 1/8 of the dropper to dropper distance, which can be used to identify the local imperfection. The instantaneous energy obtained by the Hilbert transform is used to localise the local imperfection. The effect of periodic short-wavelength irregularities can be recognised as the introduction of non-Gaussian behaviour in the contact force at specific wavelengths. Thus, spectral kurtosis is utilised to identify the deviating wavelength. The short-wavelength irregularity can be localised by the time-frequency analysis of the intrinsic mode function containing the identified deviating wavelength. The examples with measurement data indicate the validation of the present methods with some improvements to the current equipment.

An Investigation into the Characteristics of a Novel Rotatable Pantograph Catenary System for High-Speed Trains

High speed trains receive traction electrical energy from a high-voltage catenary via a pantograph catenary system (PCS). As the velocity of trains increases, the traditional PCSs face significant challenges, such as strong aero resistance under high-speed conditions, severe electrochemical corrosion caused by poor contact between the pantograph strip and the catenary, harmful wear both on the pantograph strip and the contact wire produced by high-speed sliding friction between them, etc. The effectiveness and reliability of the PCS has a direct impact on the performance and safety of the HTS power supply. In order to alleviate some of these bottleneck effects related to the operation of the currently used PCSs, especially under high-speed conditions, this paper proposes a novel configuration where rotatable pantograph rollers replace the currently used pantograph strips. As the sliding friction is now replaced by rotating friction, this has numerous benefits, such as less friction heat, better heat dispersion and improved catenary-tracking performance. Moreover, should the whole system be modularized, it could adapt to different levels of traction power through adjusting the number of rollers.