Overhead Contact Wire Research Articles

1B21 Modeling and Robust Control of a High Speed Train Pantograph(The 12th International Conference on Motion and Vibration Control)

For high-speed trains, active control of the pantograph is crucial technology to collect electrical current from the overhead contact wire. In this paper, a mathematical model of the pantograph-catenary system is developed to design a controller, and then a sliding mode controller is proposed to regulate the contact force in the presence of variation in the equivalent stiffness of the catenary system. Although the proposed controller is based on the standard sliding mode control theory, some modifications are made from a practical point of view, in particular necessary sensors for its implementation.

502 伝達マトリックス法によるちょう架式電車線の波動伝播解析(GS-10 振動解析(1))

502 伝達マトリックス法によるちょう架式電車線の波動伝播解析(GS-10 振動解析(1))

High Temperature Superconducting Cable for Railway System

In this paper, the authors present their design for the first prototype DC superconducting cable for feeding railway overhead contact wire systems. The superconducting cables will reduce the high resistive losses generated in the feeding system. For the preliminary evaluation, 2 m Bi-2223 DC cable is used. Results showed the maximum current flowing in the cable cooled by liquid nitrogen to be 1720A in the inner sheet wire and 2430 in the outer sheet. Leakage of magnetic field was determined to be negligible, and the authors conclude that the developed DC superconducting cables are reliable for use in railway systems.

고속 철도 차량용 판토그래프와 가선계의 접촉력 예측을 위한 수치 해석 모델 개발

This study aims to create a numerical analysis model which can investigate the dynamic interaction between pantograph and overhead contact wire used for a high-speed railway vehicle, and validate the simulation results according to EN 50318 standard. Finite element analysis models of pantograph and overhead contact line are created using SAMCEF, a commercial FE analysis program. The mean, standard deviation, maximum and minimum values of contact forces are obtained. The simulation results are validated according to EN 50318, and the possibility of simulating the collecting characteristic of an actual pantograph system by using the developed model is discussed.

Development of an Energy-Saving Light Rail Vehicle Powered by Large Lithium Ion Battery

A light rail vehicle (LRV) powered by a large Mn-type lithium ion battery (LIB) module was developed to run on a local railroad in Japan. A 60 kWh LIB module weighing 640 kg was used, and the relationship of running time with voltage, current, and consumed electric power was investigated in detail. The LRV was run while the LIB module was discharged between 660 V and 600 V. On a single charge, the LRV could run for 40 km by consuming around 40 kWh of energy. The running performance of the LRV with the LIB module was equivalent to that of an LRV powered electrically via an overhead contact wire. However, electrical power consumption of the LRV improved by 22% after charging the LIB with regenerative energy. The lifecycle of the LIB were examined by performing rechargeable tests. The initial capacity of the LIB was maintained at greater than 90% at 3 C (state of charge: 20%) after 3000 cycles.

Reduction of Pantograph Noise of High-Speed Trains

In order to reduce the pantograph noise that greatly contributes to overall noise, we have developed two types of low-noise pantograph. Further noise reduction was realized by the effects of attenuation of the pantograph noise insulation plate and by using only one pantograph per trainset. A multi-segment slider was also developed to increase the performance of following the overhead contact wire, which is imperative when running with only one pantograph per trainset. These countermeasures for pantograph noise have been installed on FASTECH 360 (high-speed test trains of East Japan Railway Company). The results measured by use of a microphone array show that the pantograph peak noise level is reduced by more than 2 dB compared to that of the series E2 trains now in operation.

DC Component From Pantograph Arcing in AC Traction System—Influencing Parameters, Impact, and Mitigation Techniques

Pantograph arcing in ac traction system generates transients, and causes asymmetries and distortion in supply voltage and current waveforms. These asymmetric voltage and current lead to a net dc component and harmonics that propagate within the traction power and signalling system and cause electromagnetic interference. This problem is enhanced during winter because of the layer of ice/snow on the overhead contact wire. The sliding contact becomes poor and a visible arc moves along with the pantograph. In this paper, it is shown how different parameters like traction current, line speed, power factor, and supply voltage influence the arcing, its characteristics, and the dc components. It is shown that the dc current component increases with increasing train speed and traction current, and reduces at a lower power factor. It is also discussed how the presence of an ice layer influences the arcing and the dc components. It is found that running the trains below the normal operating power factors is an effective choice to mitigate this problem. The findings presented in this paper could be beneficial to estimate the probable limit of the dc component at the planning stage so that proper precautions can be taken at the design stage itself.

Pantograph Arcing in Electrified Railways—Mechanism and Influence of Various Parameters—Part I: With DC Traction Power Supply

Pantograph arcing is a common phenomenon in electrified railway systems. This is also a source of broadband-conducted and radiated electromagnetic interference (EMI) for vehicle as well as traction power and signaling systems. In this paper and the companion paper, experimental analyses of pantograph arcing phenomena are presented for dc and ac feeding systems, respectively. Influences of different parameters on dc traction system, such as supply-voltage polarity, relative motion between pantograph and overhead contact wire, namely, forward motion along the track (longitudinal), and lateral sliding motion of the pantograph (zigzag) are presented here. From the voltage and current waveforms of the test runs, it is shown that pantograph arcing is a polarity-dependent phenomenon. For the positive-fed overhead traction system, where pantograph is cathode, the supply interruptions due to zigzag motion are comparatively less compared to negatively fed traction systems. As a result, the transients, due to pantograph arcing, are more frequent in negatively fed traction systems. It is found that the arc root movement along the electrode surfaces (pantograph-contact wire) is governed by the relative motion and polarity of the electrodes. The analyses presented in this paper also form a foundation to understand the pantograph arcing process and the corresponding influential parameters with the ac supply presented in the companion paper. The findings presented in this paper could be beneficial for coming up with appropriate mitigation techniques from the EMI due to pantograph arcing in dc-fed traction systems.

고속카메라를 이용한 전차선 압상량 검측 시스템 개발

The measurement of contact wire uplift in electric railways is one of the most important test parameters to accepting the maximum permitted speed of new electric vehicles and pantographs. The contact wire uplift can be measured over short periods when the pantograph passes monitoring stations. In this paper, a high-speed image measurement system and its image processing method are being developed to evaluate dynamic uplift of overhead contact wires caused by pantograph contact forces of Korea Tilting Train eXpress (TTX) and Korea Train eXpress (KTX). The image measurement system was implemented utilizing a high-speed CMOS (Complementary Metal Oxide Semiconductor) camera and gigabit ethernet LAN. Unlike previous systems, the uplift measurement system using high speed camera is installed on the side of the rail, making maintenance convenient. On-field verification of the uplift measurement system for overhead contact wire using high speed camera was conducted by measuring uplift of the TTX followed by operation speeds at the Honam conventional line and high-speed railway line. The proposed high-speed image measurement system to evaluate dynamic uplift of overhead contact wires shows promising on-field applications for high speed trains such as KTX and TTX.

전기철도의 전차선로 형상검측을 위한 광학기반 검측 장치 구현

We propose an optical-based measuring instrument of catenary system in electric railway. This system was made to utilize line scan camera as inspecting system to measure the stagger and height of overhead contact wire in railway and composed with optical type source and FPGA-based image acquisition system with PCI slot. Vision acquisition software has been used for the application to programming interface for image acquisition, display, and storage with a frequency of sampling. To check the validity of our approach for the intended application, we monitored height and stagger in the overhead wire of a high-speed catenary system in Korea. The proposed optical-based measuring instrument to measure the contact wire geometry such as the hight and stagger shows promising on-field applications for online condition motoring. We expect that a new generation of real-time instruments with demanding various conditions motoring requirement in railway can be easily integrated into optical-based measuring instrument system.

전차선로 해빙시스템의 온도특성

The ice coats are built on 25 kV overhead contact wire when the temperature is lower than <TEX>$0^{\circ}C$</TEX>. It generates shockwaves at the mechanical interface of the collecting strips of the pantograph and the contact wire. The de-icing processes should be performed to avoid shockwaves which are generated by a pulsed high-voltage arc discharge. This paper presents temperature analysis of the de-icing effects which could be applied to the overhead contact wire of railways using Joule heat. The results show that 350 A is the proper current for <TEX>$0^{\circ}C$</TEX> conductor according to environmental condition such as velocity of air stream, ambient temperature and moisture.

실시간 계측시스템을 이용한 전차선로 특성 측정

Facilities of electric railway should be maintained only at night and it is necessary to maintain by human power because facilities are installed at a high place. This paper presents the development and application of a real-time data acquisition system for the characteristics measurement of overhead contact wires in electric railway. The system is designed to perform in the telemetry environments that developed to store data by wireless in a live wire state of 25 kV power source. The field test results show that the proposed technique and the developed system can be practically applied to measure characteristics of temperature, displacement, and strain on overhead contact lines.

4318 相対加速度を用いたパンタグラフの接触力測定手法の研究(J27-2 交通機械における計測制御(2),J27 交通機械における計測制御)

To increase the commercial speed of train, high-performance pantographs have been developed. Simultaneously, measurement methods of contact force between overhead contact wire and pantograph have been also developed for these pantographs. This paper introduces a new contact-force measurement method which applies relative acceleration between contact strip and panhead in order to measure inertia force of pantograph.

Stereo Vision Based Measurement of Intersections of Overhead Contact wires and Pantograph of KYUSHUSHINKANSEN

It is necessary for secure commercial train services to keep the contact wires in a regular condition. Most of the contact wires are inspected by the special dedicated train set for exclusive use of measurement, such as Doctor Yellow. However it is expected to develop the inspection system using normal passenger trains and normal business operation hour, without the expensive special inspection train set. Here we developed original and compact inspection system installed on the commercial bullet train of KYUSHUSHINKANSEN. This system measured the contact points of trolley and pantograph by using image processing which acquires the sequential images of the pantograph circumference during a high-speed run with cameras installed on the narrow limits of the train roof. This report describes the image processing procedures and some measurement result of the pantograph height and contact point deviation.

Moving force on an axially loaded beam—with applications to a railway overhead contact wire

Using modal analysis, the deflection of a beam subjected to an axial tensile force N and a moving vertical force P, has been determined. This solution was exploited in a study of deflection and wave propagation in the contact wire of a railway overhead catenary system. For moderate values of speed c of the moving force P (i.e., c less than half the lowest critical speed c crit) travelling waves reflect at the boundaries of the contact wire so that the waves meet and catch up with the moving force several times. In practice, when a pantograph (here modelled by the force P) touches the contact wire some distance from the end of the wire, waves are sent out both in the forward and backward direction, giving even more reflections and wave interactions with the contact force. These waves will add or subtract to the wire deflection at the point of force application. The stress in the wire due to bending is estimated and it appears to be moderate for the speeds investigated here (i.e., for c<0.5c crit). Close to the critical speed, however, bending stresses will be significant.

Phototube sensor for monitoring the quality of current collection on overhead electrified railways

A new measurement system able to detect the occurrence of arcing between the pantograph and the overhead contact line was studied and set up. The system uses photomultiplier tubes to measure the duration of the ultraviolet emission due to electric arcing. The major advantages of the system proposed are its non-invasivity with respect to the pantograph equipment, its reliability and its low cost. Correlation with data acquired during high-speed test runs from different sensors (e.g. currents measured in an equipotential wire between the front and the rear pantographs, images acquired from a TV camera), provided the opportunity to perform an efficient calibration and an analysis of selectivity of the phototube sensor. Data from the phototube sensor along with various other information lead to the definition of a reliable index for evaluating the quality of the current collection. The determination of such an index has primary relevance for maintenance activities, for computing the minimal thrusts to be applied to the pantograph at different speeds and for testing new materials for overhead contact wires and collector strips.

A sliding wear tester for overhead wires and current collectors in light rail systems

This paper presents the dedicated experimental equipment developed for a study of the tribological behaviour of current collectors sliding against overhead contact wires under various conditions. A unique wear tester that replicates the operating conditions of actual pantographs in railway power collection systems was developed. The sliding element moves over the wire in a controlled horizontal motion at homogeneous velocity, and a constant normal load can be applied on the contact materials during this motion. Dynamic friction coefficient data, as well as the dynamic contact resistance between the contact couples were monitored using a signal collection device equipped with data acquisition (DAQ) software. The wear couples were examined in sliding using under the same normal load, in dry and lubricated conditions. The friction coefficient decreases during the test in all cases, but electrical resistance and contact resistance increase. For Cu vs. Cu in dry contact, the dynamic friction coefficient measured after run-in was 0.34 and the electrical contact resistance increased by approximately 5% after 10 6 wear cycles. Application of graphite grease — a commonly used lubricant — increased the contact resistance by about 300%. The dynamic friction coefficient of Cu vs. Cu lubricated with common grease was constant — about 0.24, and the electrical contact resistance was 1.97 μΩ. For carbon–copper composite materials (CCM) in dry sliding against Cu, the dynamic friction coefficient reduces by 20% (from 0.27 to 0.22) after 40,000 cycles, while the dynamic electrical resistance increased slightly from 5.32 to 5.35.

Innovative Solutions for Overhead Catenary-Pantograph System: Wire Actuated Control and Observed Contact Force

In this paper an innovative active pantograph for high-speed trains is proposed. The results presented are based on extensive simulation tests. The parameters used in the simulation are those of a real pantograph for high-speed trains: the pantograph model is modified by adding a wire actuation, in order to exert a constant contact force between the moving pantograph and the overhead contact wire. A wire-actuated control and contact force observers are proposed as effective solutions in the case of a possible implementation.

Systematized short-circuit analysis of a 2×25 kV electric traction network

Abstract This paper presents a systematic approach for short-circuit analysis of a 2×25 kV electric railway system. This approach uses a full-scale model of a 2×25 kV electric traction network. The model is composed of a substation model, autotransformer (AT) models, and network conductor models. The substation model considers the three most commonly used connection schemes of traction transformers. There are single-phase, V and Scott connections. The AT model considers the impedance and inherent characteristics of the AT, while the network conductor model considers the self and mutual impedances of three major conductors in a traction network (overhead contact wire, return feeder and rail). These models are all in coupling-free type. Therefore they can be easily implemented into a self-developing program or commercial packages, such as a short-circuit program in phase coordinates, the Electromagnetic Transients Program (EMTP), or the Personal Computer Simulation Program with Integrated-Circuit Emphasis (PSPICE). With the proposed models, a short-circuit analysis program is developed by the node admittance matrix method. In this manner, the fault currents in each branch in a traction network as well as the curves of fault currents versus fault location can be easily achieved. Furthermore, the voltages at the overhead contact wire and return feeder along a railway route can be calculated if required.

Wear in simulated railway overhead current collection systems

The wear rates of the pantograph contact strips and the overhead contact copper wire are investigated using a wear machine simulating a railway current collection system. The contact strip material used for the tests is the actual copper and lead-impregnated carbon used by British Rail (MY7D Grade) on all pantographs. Wear rates of the contact strip and copper disk (simulating the overhead contact wire) are presented and discussed. Disk wear is measured in situ by the spherical indentations method. The wear performance at speeds from 60 to 250 km h −1 is examined with and without current collection. The dependence of the wear rate on the current (0–300 A both a.c. and d.c.), the static contact force (1.0–250 N) and the dwell time for intermittent sliding has been determined. A comparison with previous results is given where applicable. The dwell time, representing the time lapse between pantograph passes, is shown to have a crucial effect on the copper wear depth per passage owing to the formation and subsequent removal of an oxide layer on the copper surface.