Current Collection Performance Research Articles

Computational evaluation of PEMFC performance based on bipolar plate material types

Materials used in bipolar plates are essential for addressing the challenges associated with the large-scale commercialization of Proton Exchange Membrane Fuel Cells (PEMFCs). Therefore, it is necessary to develop effective performance evaluation approaches to evaluate the performance of materials. This work has presented a high-fidelity mathematical model that includes electrochemical, fluid flow, energy, species transport, water formation, and transport aspects to simulate the conditions in a PEMFC system and to theoretically assess the performances of commercial bipolar plate materials. Accordingly, the effects of metallic (aluminum) and carbon-based (graphite and graphite composite) bipolar plate materials on the current collection performance, thermal management, water management, and overall efficiency of PEMFCs are analyzed. The findings suggest that the current density, power density, and operating voltage of each PEMFC are greatly affected by the bipolar plate material used. When compared to graphite bipolar plates, the aluminum and graphite composite bipolar plates have exhibited 16.5 % and 7.5 % higher power densities, respectively. The change in operating conditions and thermal environments caused by a change of bipolar plate materials gives rise to distinct water transport phenomena according to their respective capabilities in the balancing of liquid water movements across the membrane, which in turn affects the species distribution pattern. Specifically, the high imbalance between the electro-osmotic drag and back diffusion in the case of aluminum bipolar plate leads to a severe membrane dry-out on the anode side, limiting the hydrogen concentration in the region.

Modelling dynamic pantograph loads with combined numerical analysis

Appropriate interaction between pantograph and catenary is imperative for smooth operation of electric trains. Changing heights of overhead lines to accommodate level crossings, overbridges, and tunnels pose significant challenges in maintaining consistent current collection performance as the pantograph aerodynamic profile, and thus aerodynamic load changes significantly with operational height. This research aims to analyse the global flow characteristics and aerodynamic forces acting on individual components of an HSX pantograph operating in different configurations and orientations, such that the results can be combined with multibody simulations to obtain accurate dynamic insight into contact forces. Specifically, computational fluid dynamics simulations are used to investigate the pantograph component loads in a representative setting, such as that of the recessed cavity on a Class 800 train. From an aerodynamic perspective, this study indicates that the total drag force acting on non-fixed components of the pantograph is larger for the knuckle-leading orientation rather than the knuckle-trailing, although the difference between the two is found to reduce with increasing pantograph extension. Combining the aerodynamic loads acting on individual components with multibody tools allows for realistic dynamic insight into the pantograph behaviour. The results obtained show how considering aerodynamic forces enhance the realism of the models, leading to behaviour of the pantograph–catenary contact forces closely matching that seen in experimental tests.

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.

Current Collection Performance of Overhead Contact Line with Aseismic Pull-off Arm

Current Collection Performance of Overhead Contact Line with Aseismic Pull-off Arm

The current collection performance of multi-segment pantograph head

The current collection performance of multi-segment pantograph head

사물인터넷 기반 장력조정장치 상태 모니터링 시스템 구현

The contact wire made of copper or copper alloy is installed to keep a good current collection performance between a pantograph and catenary system. The tensioning device installed in a contact and messenger wire is required to have high reliability as a major component of the feeding facility which keeps constant tension of the wires regardless of temperature changes. The maintenance of the tensioning device is generally performed by the man power. In this paper, we propose a condition monitoring system for a spring tension device using sensor network and communication based on Internet of Thing. The proposed monitoring system is composed of a structure integrated with tensioning device by applying an ultrasonic sensor with minimum power consumption and communication device. It was able to monitor the dynamic state of the tensioning device according to temperature change n real time through the displacement of ultrasonic sensor.

Examining the effect of the secondary flow-field on polymer electrolyte fuel cells using X-ray computed radiography and computational modelling

Flow-fields are key factors in determining the operation of fuel cells. While extensive work has been conducted to develop and optimise the reactant flow and current collection performance of polymer electrolyte membrane fuel cell (PEMFC) components, there is a factor that remains largely unaccounted for. Depending on how a membrane electrode assembly (MEA) is incorporated into a cell, there will often be a small gap between the edge of the gas diffusion layer (GDL) and the seal or bipolar plate. This gap acts as a ‘secondary flow-field’ (SFF) that can bypass or affect/augment the conventional or ‘primary flow-field’. Understanding how this affects performance (either positively or adversely) is essential for holistic flow-field design. This paper describes the issues associated with the SFF, examines how cell compression affects its width due to lateral expansion of the GDL and discusses the results of a 3-D computational model that investigates the effect of the SFF during dead-ended anode (DEA) operation for a fuel cell without a macroscopic (conventional) anode flow-field.

수서고속철도 전차선로의 설치조건의 따른 집전상태 분석

This paper describes the dynamic characteristics depending on installation condition between a pantograph and an OCL (Overhead Contact Line) on a new high speed line in Korea. The current collection performance between the pantograph and the OCL was tested during train operation from Suseo to Jije stations. The current collection performance is evaluated based on the duration of an arc by using an arcing measurement system. The system consists of an optical sensor for measuring the duration of an arc and a camera for monitoring current collection performance. An arcing duration is defined as a percentage of arcing in international standards. This test aims to analyze the locations of repetitive arcing depending on installation conditions of OCLs on a new high speed line in order to use the result as reference data for correct construction and maintenance.

강체전차선로 고속화를 위한 설계파라미터 민감도 분석 연구

R-Bar (Overhead Rigid Conductor system) has been lately used for the speed of over 200 ㎞/h in Europe, while it has been developed and used for the max. speed of 120 ㎞/h in Korea. Because R-Bar has advantages of reduction of tunnel cross sectional area and maintenance, its development for more high-speed is urgent in Korea having many mountain area. Therefore a sensitivity analysis of design parameters for the speed-up of R-Bar has performed in this study. For the analysis, we have developed a program for the prediction of dynamic characteristics between a pantograph and R-Bar. The program was evaluated with the actual test result and a current collection performance according to the parameters such as a distance between brackets, a stiffness of bracket and of R-Bar rail was predicted with the program.

전차선로 동적특성에 따른 설치상태 분석

The measurement of current collection performance between pantograph and contact wire of overhead catenary system is intended to prove the safety of operation and the quality of the current collection system. The results of interaction performance of current collection system are required for approving with commercial operation on railway lines. The methods of interaction performance of current collection system are defined on interactional standards such as IEC 62486 and EN 50317. In this paper, the interaction performance is evaluated by the percentage of arcing on Honam high-speed line and the results are used for adjustment of the overhead catenary line structure. The experimental results in Honam high-speed line confirm that the duration of an arc lasting longer 25 ms between pantograph and contact wire was depended on the conditions of overhead contact line after installation.

New Monitoring Technologies for Overhead Contact Line at 400 km·h −1

Abstract Various technologies have recently been developed for high-speed railways, in order to boost commercial speeds from 300 km·h−1 to 400 km·h−1. Among these technologies, this paper introduces the 400 km·h−1 class current collection performance evaluation methods that have been developed and demonstrated by Korea. Specifically, this paper reports details of the video-based monitoring techniques that have been adopted to inspect the stability of overhead contact line (OCL) components at 400 km·h−1 without direct contact with any components of the power supply system. Unlike conventional OCL monitoring systems, which detect contact wire positions using either laser sensors or line cameras, the developed system measures parameters in the active state by video data. According to experimental results that were obtained at a field-test site established at a commercial line, it is claimed that the proposed measurement system is capable of effectively measuring OCL parameters.

400km/h 전차선로에서 사전이도가 집전성능에 미치는 영향에 대한 시뮬레이션 및 시험

A 400km/h simple catenary system was constructed as a test line in Korea. In the design stage of this system, the pre-sag was one of the engineering issues most focused on. It is known that the pre-sag improves the current collection performance in a certain band of high speed. However, the effect of pre-sag at 400km/h has not yet been established. To grasp a better pre-sag in the 400km/h catenary, we transacted the dynamic performance prediction simulation between catenary and pantograph under conditions of 0 and 1/3000 pre-sag. The level of 0 pre-sag was adapted for the 400km/h catenary design after reviewing predictions. We constituted the 1/3000 pre-sag sample section (about 1km) while constructing the 400km/h catenary test-bed (28km) of 0 pre-sag. With a HEMU-430X train, the contact forces were measured in the test-bed including the pre-sag sample section. In this paper, the predicted and measured dynamic performance values (contact forces) for 0 and 1/3000 pre-sag are described and compared. It is conclusively confirmed by analytical and experimental examination that the non pre-sag showed better dynamic (current collection) performance than that of the 1/3000 pre-sag for the 400km/h catenary system.

350km/h 전차선로 집전성능 시험 및 결과 분석

The 350[km/h] catenary system was successfully opened in Honam high speed line. This 350[km/h] catenary system is firstly constructed in South Korea. Therefore the current collection performance of this system should be tested and evaluated by the authority. This paper describes the testings by running of HEMU-430X train and the evaluation criteria and result analysis to determine whether the performance of the catenary is good or not as a verification of catenary-pantograph interface. In detail, the contact force by pantograph, arcs by loss of contact and uplift amount of the catenary support were measured and discussed as a category of the current collection performance.

<b>Effect of Temperature Change and Contact-wire Wear on Current Collection Performance</b>

For electric railways, it is preferable for the tension and height of overhead contact lines to be constant to maintain satisfactory current collection performance. Since overhead contact lines expand and contract according to temperature change, an automatic tension balancer is generally installed at the terminations. However, the tension of overhead contact lines is not always constant because of tension fluctuations in automatic tension balancers and the gradient of the yokes. In addition, contact wire wear causes its mass to decrease. This also affects the contact wire tension and height. The authors performed a theoretical study and a simulation. As the results of them, we clarified the effect of temperature change and contact-wire wear on current collection performance.

고속전차선로의 시공 허용오차가 집전성능에 미치는 영향에 관한 연구

In this paper, analysis of the effects for construction tolerances on the current collection performance of high speed catenary system. The height of the contact wire is the geometrical position of the cantilever directly affects the current collection performance. Contact force when the height of the contact wire exceeds the construction tolerance were analyzed. As a result, the maximum contact force was analyzed to more than 350[N] that are recommended by EN50119.BR And when the geometrical position of the cantilever to exceeds the construction tolerance, the analysis results of uplift at the mast support points, it becomes 127[mm] that are recommended by UIC 799. If the construction tolerances exceeds the reference value, the current collection performance is deteriorated. Therefore, catenary system require high precision construction. In the future, there is a need for continuing research on the tolerance of catenary system in the actual operating state.

An arc-light-based method for estimation of contact strip wear

A measured contact-loss ratio is used to estimate current-collection performance. There are two types of methods used to estimate the contact-loss ratio. One is to measure all the contact losses, including small ones; the other is to measure only contact losses that are greater than 5 ms in duration. The extent of wear of a contact strip caused by arc discharges varies as a function of the amount of electric charge. This fact makes it possible to manage the wear on a contact strip. This paper shows a calculation method for the amount of electric charge based on the output of a contact-loss measurement as well as the expected lifetime of the contact strip and the creation of a maintenance threshold level for of the contact strip.

Analysis of dynamic interaction between catenary and pantograph with experimental verification and performance evaluation in new high-speed line

Understanding the dynamic interaction between the catenary and pantograph of a high-speed train is the one of the most important technical issues in the railway industry. This is because the catenary–pantograph system plays a crucial role in providing electric power to the railway vehicle for stable operation. The aim of the present paper is to estimate the current-collection performance of this system by using numerical analysis, in particular, the flexible multibody dynamic analysis technique. To implement large deformable catenary wires, an absolute nodal coordinate formulation is used for the cable element. Additionally, an efficient contact element and an interactive model for the catenary–pantograph system are introduced. Each developed model is then used for analytical and experimental verification. Actual on-line test results of existing high-speed railway vehicles are presented and used to verify the analysis model. Finally, the performance characteristics of a new 400 km/h-class high-speed line are estimated and evaluated on the basis of international standards.

高速用き電ちょう架方式架線の開発

In Japan, the maximum speed of meter-gauged railway lines (conventional lines) is 160km/h. In recent years, the overhead contact line with a feeder messenger wire, which has the features of labor-saving maintenance and construction cost reduction, has attracted attention. Because further high-speed performance is required, even for meter-gauged railway lines, the development of the overhead contact line with a feeder messenger wire that has excellent high-speed performance is desired. Therefore, compound catenary equipment with a feeder messenger wire has been developed for meter-gauged railway lines. This overhead contact line enables a train to operate at a speed of 160km/h and maintain the features of labor-saving maintenance and construction cost reduction. We performed theoretical analyses and a dynamic-characteristic evaluation to confirm the validity of the overhead contact line. Moreover, we conducted a test run to verify the current collection performance of the overhead contact line.

전차선의 집전상태 판단 알고리즘 구현

Analyzing dynamic performance between pantograph and contact wire depends on mechanical and electrical conditions such as contact force, currents, aerodynamics of pantograph and tension of overhead contact wire. For the characteristic of dynamic performance between pantograph and overhead contact wire, various evaluation systems are used to measuring of the interaction of the contact line and the pantograph. Among the various methods, the contact force and percentage of arcing are intended to prove the safety and the quality of the current collection system on the train. However, these methods are only capable of measuring on the train which are installed measurement systems. Therefore in this paper, a track-side monitoring system was implemented to measure electrical characteristics from active overhead contact wire systems in order to constantly estimate current collection performance of railway operation. In addition, a method to analyze loss of contact phenomena was proposed. According to simulation results, the proposed system was capable of measuring abnormal electrical behavior of pantograph and contact wires on the track-side. The advantage of the proposed system is possible to detect loss of contact or any other electrical abnormalities of all types of trains within sections from sub to sub without the need to install any on-board equipment on trains.

선로변 전차선과 조가선의 전류를 이용한 집전성능 분석 기술

In this paper, analysis method for current collection performance based on real-time current of catenary system is proposed. An innovative method based on track-side of railway system is used for measurement of currents for overhead contact line during the collection with pantograph. The evaluation of a qualitative ratio for current collection performance were conducted using proposed algorithm under various conditions such as laboratory and track-side. To check the validity of our approach, we compared between calculation results from current of contact wire and measurement results from arcing of pantograph using simulator in laboratory conditions. The results show that the behavior of current collection performance were analysis from currents of overhead contact line in AC electric railway system.