Overhead Contact Line System Research Articles

Modelling and simulation of double-pantograph catenary system of Taiwan railway

Abstract In view of the insufficient transportation capacity of Taiwan Railways in populated urban areas and intercity railways, increasing the maximum operating speed can be a solution for the problem. However, it is unknown whether the overhead contact line (OCL) system of the Taiwan Railways can tolerate such speed changes. For the unique railway system used in Taiwan, the literature does not present research on the dynamic interaction behaviour for the typical EMU trains with two pantographs, which are widely used in Taiwan railway system. Further, in response to the government policy to localize the supply chain of railway components, this research aims to establish a reliable simulation model so that domestic manufacturers may use this model for the design and development of the pantograph-catenary system. In this study, the catenary system model is established based on theoretic principles, specifications and parameters are adapted from data used by Taiwan Railway Co. The pantograph model was constructed as multi-body model, with parameters taken from the pantograph equipped on the TEMU2000 tilting train. This model is used to analyse catenary system to investigate the potential loss of contact between the double pantographs and the contact wire with increased train speed. The loss of contact and other phenomena will be analysed to explore possible solutions or optimization strategies for catenary system design.

Availability of an Overhead Contact Line System for the Electrification of Road Freight Transport

Availability of an Overhead Contact Line System for the Electrification of Road Freight Transport

Effect of Overhead Contact Line Pre-Sag on the Interaction Performance with a Pantograph in Electrified Railways

In the high-speed rail industry, the overhead contact line erected along the railroad is used to supply the electricity to the high-speed train via a pantograph on the carbody’s roof. This work attempts to explore the effect of contact line pre-sag on the contact quality between the pantograph and the contact line. A nonlinear finite element approach is implemented to build the overhead contact line system with accurate description of the pre-sag of the contact line. Through a nonlinear solution, the effect of contact line pre-sag on the contact force is analysed with different train speeds and tension classes. The analysis result indicates the feasibility of tuning the pre-sag to improve the interaction performance at a given speed and tension class. In the low-speed range, the change of pre-sag does not have a significant effect on the interaction performance. However, when the speed increases up to a certain value, the effect of pre-sag on the contact force is nonnegligible. The increase in tension can reduce the sensitivity of the interaction performance to the pre-sag. An optimisation procedure is implemented to obtain the optimal amount of pre-sag for different train speeds and tension classes. The results indicate a necessity to include a certain amount of contact line pre-sag to maintain an excellent interaction performance at high speed.

Dynamic behaviour of railway poles built on bridges under train passage in high-speed railways and a simple evaluation method

There have been studies on increased dynamic response of bridges for high-speed railways (HSRs) and damage to the overhead contact line system (OCS), including wires supported by railway poles placed on resonant bridges. However, the dynamic behavior of the poles installed on bridges under train passages, which is considerably related to the damage to the OCS, has not been systematically examined. This study aims to examine the dynamic behaviour of poles installed on bridges and provide a simple calculation method or guidelines for bridge design and OCS maintenance considering pole vibration. First, a field test of a HSR bridge with poles was conducted, and numerical simulations using a finite element model of pole and bridge were validated. Next, a parametric study using the validated numerical model was conducted. The results demonstrated that the multiple resonances observed when the excitation frequency of travelling train matches the bridge and pole frequencies can cause dominant vibration of the poles built at the bridge edge, thus posing a risk of OCS wire fatigue. In addition to the understanding of the basic dynamic behavior, a simple calculation approach based on a theoretical model considering the interaction between the bridge and poles installed at the bridge edge is developed for practical use. The proposed model clarifies train-induced pole top displacements with standard bridge and pole specifications in Japanese HSRs. Using the bridge/pole frequency ratio and bridge span length, the results are presented in the form of a pole response map that can be used to calculate the pole top displacement. Finally, an example of bridge frequency guidelines is provided for extracting and evaluating poles that may require attention for maintaining the OCSs.

Panhead accelerations-based methodology for monitoring the stagger in overhead contact line systems

The monitoring of overhead contact lines (OCL) is a key part of railway infrastructure maintenance. This paper proposes a methodology to assess the lateral geometry of contact wire, the so-called stagger, by using the dynamic response of a pantograph. The methodology is tested in a validated virtual environment that resembles the behaviour of the pantograph when it interacts with the OCL. A signal processing is developed to define features relating the lateral position of the contact wire with the vertical acceleration of the contact strip. It is demonstrated that these features have a clear and close connection with the lateral position of the contact wire. Subsequently, model-driven machine learning algorithms are defined using these features to address the OCL stagger prediction and the detection of out-of-range lateral displacement due to a faulty steady-arm. The methodology shows a good prediction performance in the estimation of the stagger amplitude/central position and the steady-arms diagnosis. The prediction of the stagger amplitude is performed with a root-mean-square error of 4.7(10)mm. In addition, the area under the Precision–Recall curve is 0.952 CI95 [0.940, 0.962] for the steady-arms diagnosis.

Pantograph Spark Fault Detection using YOLO

Pantograph-catenary is now the dominant form of current collection for modern electric trains because they can be used for higher voltages. Faults in pantograph-catenary systems threaten the operation and safety of railway transportation. They need to be continuously monitored and controlled to maintain safe transport. Pantograph may be damaged as a result of extreme weather conditions which can affect its normal operation, leading to failure of pantograph and overhead contact line systems. Poor contact between pantograph and overhead contact line causes thermal erosion to the wire. When the pantographs are exposed to air, they could deteriorate due to electrochemical reaction with the environment since they are made of metals. Movement of catenary lines and pantograph in high crosswinds has been found to cause the wire to be trapped in the pantograph. There is a serious issue regarding the quality of images generated by pantograph video monitoring system on high-speed railway trains which often shows inconsistencies of catenary faults. The application of traditional image processing and deep learning techniques have been unable to meet the requirements of spark detection. In this paper, a modern deep learning algorithm is proposed to detect sparks in the pantograph. Specifically, the YOLOv3 model is used to counter this problem that traditional image processing algorithms have been unable to. The results on a very large sample of data show the efficiency and real-time performance of the proposed method, which meets the requirements of pantograph spark detection in high-speed railway. Keywords : High-speed railway pantograph; Spark detection; Deep learning; YOLOv3; DOI: 10.7176/ISDE/12-3-02 Publication date: September 30 th 2021

Prognostics and Health Management for an Overhead Contact Line System - A Review

The railway industry in European countries is standing a significant competition from other modes of transportation, particularly in the field of freight transport. In this competitive context, railway stakeholders need to modernize their products and develop innovative solutions to manage their asset and reduce operational expenditures. As a result, activities such as condition-based and predictive maintenance became a major concern. Under those circumstances, there is a pressing need to implement prognostics and health management (PHM) solutions such as remote monitoring, fault diagnostics techniques, and prognostics technologies. Many studies in the PHM area for railway applications are focused on infrastructure systems such as railway track or turnouts. However, one of the key systems to ensure an efficient operability of the infrastructure is the overhead contact line (OCL). A defect or a failure of an OCL component may cause considerable delays, lead to important financial losses, or affect passengers safety. In addition maintaining this kind of geographically distributed systemsis costly and difficult to forecast. This article reviews the state of practice and the state of the art of PHM for overhead contact line system. Key sensors, monitoring parameters, state detection algorithms, diagnostics approaches and prognostics models are reviewed. Also, research challenges and technical needs are highlighted

Dynamic Performance of High-Speed Railway Overhead Contact Line Interacting With Pantograph Considering Local Dropper Defect

The local dropper defect is the most common fault in the early service stage of the overhead contact line (OCL) system. The plastic deformation and loose of a dropper may cause the variation of the contact line height, which has a direct effect on the contact performance of the pantograph-OCL system. This paper proposes a methodology to model the OCL with local dropper defect using a nonlinear finite element approach. Employing a developed TCUD (Target Configuration under Dead Load) method, which takes the vertical defective dropper position in the contact line as additional constraints, the local dropper defect is exactly added in the initial configuration of the OCL model. Several simulations of pantograph-OCL interaction are run with different positions of the defective dropper. The effect of local dropper defect on the pantograph-OCL contact forces is analysed. The results show that the increase of the defect degree causes the increment of the contact force peak around the defective dropper point. The defect on the first or last dropper within a span is the most detrimental to the current collection quality, as it directly causes the increase of maximum contact force, which challenges the safe operation of the pantograph-OCL system, and should be strictly restricted. The PSD (Power Spectral Density) analysis of contact force indicates that the dropper defect distorts the frequency characteristics of the contact force. The energy of contact forces decreases at the dropper-interval related frequencies due to the presence of dropper defect. Similarly, a significant `break' of the dropper-interval frequency component can be observed in the time-frequency representation of the contact force. This phenomenon has the potential to be used to identify and locate the defective dropper from the measured contact force.

Inspection Technology of Overhead Contact Line System from Rolling Stock

Inspection Technology of Overhead Contact Line System from Rolling Stock

Power Supply System Implemented on Polish High Speed Lines and Pantograph-OCL Interaction Quality Assessment Based on Tests Performed on PKP Network

In this paper the 3kV power supply system of Polish high-speed lines is described. Basic OCL parameters and test results of current collection quality is presented. One of the basic parameters limiting the maximum service speed on a given line is the pantograph-OCL cooperation quality. In this paper three types of overhead contact lines designed and implemented in Poland are described. There are also specified basic parameters and materials of catenaries, as well as OCL geometry or mechanical and electrical design values. The measured values obtained as a result of the performed tests are given in this paper which allows them to be compared with the design intents. One of the overhead contact line system examples is an OCL system implemented on CMK mainline. The line was built in the 1970s and nowadays is a backbone of Warsaw to Silesia rail connection. Today PKP provides 200km/h commercial intercity services on this line. The CMK trunk line is commonly considered as a leading one on the Polish rail network. On this line several tests were performed which allowed the following two types of traction stock to enter service on the domestic network. The first of them was Siemens ES64U4 electric locomotive and the second one was ED250 Pendolino electric multiple unit, manufactured by Alstom Ferroviaria. All these tests were carried out according to the requirements described in Technical Specifications for Interoperability (TSI) of Trans-European high-speed rail network for both Test pantograph and catenary on compliance with the TSI Energy and locomotives subsystems. During the Pendolino test runs two consecutive speed records were attained, first one (250.1 km/h) by a modified FS ETR460 train in 1994 and the latter (293 km/h) by a PKP ED250 train in 2013. It is to be noticed that the speed records mentioned above were determined not only by the power supply system parameters but were dependent on other factors as well. During the test runs the current collection quality was checked, for both single-unit and multiple-unit operation. In this paper the results of pantograph-OCL cooperation are described, according to TSI “Rolling stock” and “Energy” subsystems. These specifications state that the general current collection quality assessment criteria are the contact wire uplift and the contact force (calculated between a collector head and the contact wire).

The Strength Analysis of Pre-Tightening Force on Covering Pipe-Ear

The covering pipe-ear is one of the important components of the overhead contact line system (OCS) for supporting loads. The finite element model of covering pipe-ear was established, as the pre-tightening force, wind load and ice load all have effect on it, the stress distribution law were simulated under 12 kinds of loading conditions. The results show that the pre-tightening force has remarkable influence on covering pipe-ear and 2500N pre-tightening force is appropriate for the aluminum alloy covering pipe-ear. It is useful for the catenary components static strength reliability design.

Design and Development of Superconducting DC Cable for Railway Applications

We report the recent development in the national project dealing with a prototype of the next generation dc superconducting cable for railways. The main goal of the project is to upgrade the feeder of the overhead contact line system connecting the electric train with the substation. The superconducting cables are usually considered to reduce the resistive losses generated in a conventional feeding system mainly in the catenary wires. In this paper, various cable structures existing in the railway network were studied with respect of their use in the next generation of railways. The superconducting cables need to be cooled below 77 K. They consist of coaxially configured conductors and sheaths. Liquid nitrogen is forced to flow through these coaxial cables. Various designs and configurations of the cooling systems possess always some advantages and some drawbacks. Our systematic analysis showed that a `go and return' system, where the liquid nitrogen flows through the hollow former and returns through the space between the outer layer of the HTS tapes and the cryostat wall is most effective for the railway applications; it saves both space and costs.

전차선로 전기적 특성 평가 시스템 구현

Currently in Korea, the simple catenary type overhead contact line system is being applied to both conventional lines and high speed lines of electric railway, and circulation current flowing into the catenary system frequently bring undesirable consequences. Namely, the connector wire has many problems according to a flow of excessive circulation current and arc current on catenary when an electric train runs at high speed. This paper presents the development and application of a real-time data acquisition system designed to measure the electrical characteristics of an overhead catenary system in electric railways. The developed system is capable of storing data of a 25 kV power source in a live wire state through a telemetry environment. The field test results show that the proposed technique and the developed system can be practically applied to measure characteristics of current of an overhead catenary system.

Validation of Contact Wire Simulations on the Basis of Scaled Down Contact Wire Cutting Experiments

As the requirements for overhead contact line systems increase due to higher train speeds, the need of safety equipment for these systems increases as well. Developing a component for the case of a contact wire cut to prevent further damage from the overhead contact line system requires an extensive knowledge about the system behaviour. Therefore, a comprehensive multi body system model (MBS) is developed in Matlab SimMechanics environment. In order to validate the datas generated from the simulations, a contact wire test stand has been constructed where cutting experiments can be run by releasing a pretensioned wire. Consequently, the force distribution during the contact wire cut is analyzed and these values are compared with the simulation results. For the comparisons, much attention is given to the period after the contact wire cut.

Determination and Optimization of the Maintenance Frequencies in the Overhead Contact Line System

This paper proposes a methodology to determine the optimum maintenance frequencies for the components of an electric railway overhead contact line system. This methodology is aimed at improving the reliability and availability of each component within its operational context and calculates the maintenance frequencies according to the criticality of each component, the importance of the area in which they are installed, and the component performance. The available maintenance team resources are also taken into account in order to optimize the frequencies and make them feasible for the maintenance team. The proposed methodology uses statistical and optimization tools to take advantage of the information obtained through the careful analysis of the historical data related to the system performance, which allows an objective determination of appropriate maintenance frequencies. Furthermore, it allows establishing the frequencies in a dynamic way through a feedback process. To prove the usefulness of the proposed methodology, a case study is presented in which maintenance frequencies of some components of the overhead contact line of the Spanish railway network are determined.

Development of prototype DC superconducting cable for railway system

High Temperature Superconducting (HTSC) wire has significant potential for railway system applications. HTSC wire is currently a promising candidate for various engineering applications such as transformers and motors for railway system. HTSC direct current (DC) cable is ideal for a feeder of the overhead contact line system between the substation and the electric train. We completed a prototype Bi-2223 tape based direct current cable for trial purposes of several meters length. In the energizing experiment the current of 1720A successfully constantly flew.

Criticality determination based on failure records for decision-making in the overhead contact line system

In this article, a new methodology to determine the criticality of the components of the overhead contact line (OCL) system by means of a component criticality index is proposed. The methodology is based on classic failure mode and effects analysis (FMEA) but adapted to its application on this system, with characteristics far from industrial systems where FMEA was developed. The procedure is focused on the analysis of the system's operating history with the important advantage that the subjectivity of the usual procedures is reduced. This methodology has proved to be very useful when applied to decision-making and for establishing maintenance frequencies of the elements of the OCL of the Spanish railway network, and it could also be applied to other kind of large-scale distributed systems.

FBG 센서를 활용한 온도와 스트레인 변화 모니터링

This paper reports on measurement method for the fiber optic strain monitoring of overhead contact line systems of trains, We used FBG (Fiber Bragg Grating) sensors to measure the strain variation of overhead contact line. FBG sensors can sensitively measure the variation of strain and! or temperature by the shift wavelength of reflected wave according to the lattice variation during the measurement. FBG sensor were attached on the contact line and connected to the monitoring system with optical fibers. The monitering system with FBG sensors showed very good sensitivity to measuring strain variation and this system could be applied to the overhead contact line of KTX (Korea Train eXpress).

Development of Simple Catenary Equipment Using PHC Contact Wire for Shinkansen

Public awareness of global warming and recycling has created a demand to respect environmental conservation and reduce the environmental burden posed by railways. To this end, it is necessary to extend the replacement frequency of the contact wire in the overhead contact line system and apply a copper alloy to improve its recycling efficiency. We therefore selected a new type of equipment (known as PHC simple catenary equipment) through research into the overhead contact line system, performance calculations from simulation, and running tests at our institute. In the final stage of development, we installed the PHC simple catenary equipment on a commercial line to confirm its performance.

Online temperature monitoring of overhead contact line at the new German high-speed rail line Cologne-Rhine/Main

This paper describes the first fiber-optic temperature measurement of overhead contact line systems at the new ICE3 high speed line of the German Railway. The installation of Fiber Bragg Grating (FBG) sensors, the online acquisition and interrogation of data over a one year period is presented.