Electric Railway Systems Research Articles

국내 교류 전기철도 급전계통 보호용 과전류 계전기 모델링 및 과부하 보호 협조에 관한 연구

국내 교류 전기철도 급전계통 보호용 과전류 계전기 모델링 및 과부하 보호 협조에 관한 연구

Hardware-in-the-Loop Simulation of Superconducting Devices for DC Electric Railway Systems Based on a Real-Time Digital Simulator

We have developed a hardware-in-the-loop (HIL) simulation setup to analyze superconducting devices for dc electric railway systems. When such superconducting devices are to be installed into a larger system, it is indispensable to characterize their behavior, i.e., their interaction with the system, to assure their reliability in all operating conditions. This is challenging when using full-scale superconducting devices and real power systems because many types of operation and fault cannot be easily demonstrated. Numerical simulation may compensate for that, but complete modeling of superconducting devices has often been difficult because of complicated electromagnetic behavior due to nonlinear transport properties, the transition between superconducting and normal states, and so on. In this paper, we have established an HIL simulation setup by the combination of superconducting hardware and a real-time digital simulator (RTDS). They communicate information about the instantaneous current and voltage values to each other every 50 $\upmu$ s. This enables us to simulate the interaction between superconducting devices and the system for many kinds of operation and fault. Furthermore, it is not necessary to use a full-scale superconducting device, as the signal level from/to the RTDS can be scaled. This will be very attractive for understanding the behavior of a superconducting device by studying a small prototype before developing the full-scale one.

Optimal power flow with storage in DC electrified railways

Purpose Due to the increase of the traffic, issues are appearing on DC electrified railway feeding systems. One candidate solution to solve these issues and to improve their performances is to add storage systems in the railway DC electrical network. The paper presents a method based on an Optimal Power Flow (OPF) for the analysis and design of DC railway feeding systems with storage. Design/methodology/approach The paper describes a new methodology based on optimization to study DC electrified railways, including storage systems. A load flow model of a DC 1500V railway electrification system is presented, including the mobility of the train sets. Then, an Optimal Power Flow model of the DC network, including energy storage systems and feeding substation rectifiers has been developed. Finally, the OPF model has been tested on a real application case showing its benefits while searching solutions in order to improve the network performances. Findings An OPF model suitable for analysis of DC networks with storage is presented. It shows its ability to solve large scale problems. Research limitations/implications The paper focuses on the physical model of the network. The optimization model will have to be extended with application constraints. Originality/value The hypothesis presented in this paper allows to remove the discontinuities of the system in order to use a continuous optimization approach.

Indoor and outdoor measurement of airborne particulates on a commuter train running partly in tunnels

Wear processes from mechanical braking, rail/wheel contact, the railway electrification system and re-suspended materials due to the turbulence of passing trains in tunnels and stations have been suggested to be the main contributors to particulate matter levels inside trains. In this study, onboard monitoring was performed on a commuter train stopping at underground and aboveground stations. The concentration and size distribution of particulates were monitored for both indoor and outdoor levels. The results show that the levels of PM10 and PM2.5 inside the train were about one-fifth of the outdoor levels. Significant increases in indoor particulate number concentrations were observed in tunnel environments and there was a slight increase when the doors were open. Differences in the size distributions of micro- and nano-sized particulates could be identified for different tunnels.

강체전차선로의 특성을 고려한 급전시스템에서 이선에 따른 철도차량 전력변환장치에 대한 특성에 관한 연구

In this paper, Characteristic of power conversion unit of a railway vehicles according to contact loss in feeding system that applied impedance of rigid conductor is analyzed. It applied impedance of rigid bar in modeling of electric railway system. Railway vehicles are performed of modeling based on the performance of the electric railway vehicle. Effects of the contact loss in the power conversion unit were analyzed via main transformer of railway vehicle, the input and output voltage characteristics of the converter through contact loss was generated after linking the vehicle with feeding system.

Simulation on Voltage Unbalance Reduction in Railway Electrification System by Different Special Transformers

In recent years, electric railway system becomes an efficient mass transportation in large urban areas. A railway electrification system supplies electric power to railway trains through the transformers. Therefore, the transformer is a key component to help reduce problems of the unbalance of voltage and current in the power grid. As electric trains have their power delivered on a single-phase system, the single-phase transformer causes the unbalance of voltage and current in the power system network, with which the railway electrification system is connected. In order to alleviate these problems, special transformers, i.e. Scott transformer and Le-Blanc transformer, have been proposed to be used in the railway electrification system. This paper focuses on developing the special transformer models for using in DIgSILENT PowerFactory software. The developed models have been verified with a simple train system in order to study the effectiveness of reduction of voltage unbalance factors from the three types of transformers. In addition, the developed special transformer models can be applied in a large-scale power system network for power quality problem analysis.

Protection of a multiterminal DC compact node feeding electric vehicles on electric railway systems, secondary distribution networks, and PV systems

This paper describes a multiterminal DC compact node consisting of voltage-source converters and DC-DC converters as a promising arrangement to feed electric vehicle (EV) charging stations with renewable power sources. This research analyzed the behavior of the node currents under DC faults, and more specically their natural response, which can produce challenging electrical protection requirements. An electrical protection system was thus designed based on the use of protective devices that included protective relays, solid state circuit breakers and hybrid circuit breakers. These protective devices monitor local readings to detect and isolate DC faults as quickly as possible. This highlighted the fact that there are devices, available on the market, that comply with the fast response requirement to prevent damage or destruction of the converters andlter capacitors of the node.

Operation analysis of AC traction motors in terms of electromagnetic torque capability on sustainable railway vehicles

Sustainable operation of electric railway systems represents a significant purpose nowadays in the development of high power and high speed locomotives and trains. At present, high speed electric vehicles mostly work with three-phase induction motors or three-phase synchronous motors as traction motors. The two electric machine types have different efficiencies at different operation points, and experience differences with respect to safety, speed and power, energy use and exergy efficiency. An important issue that correlates these aspects is the electromagnetic torque developed by an electric traction motor. In order to provide an overview of the technical performance of the operation of sustainable railway systems, a detailed analysis is carried out of the electromagnetic torque capability of AC electric motors utilized as traction motors in modern locomotives of high power and/or high speed. The results of this work may help in enhancing the main criteria for optimising the safe and sustainable operation of electric railway traction systems.

350km/h급 고속전차선로 보호선의 선종결정 기법에 관한 연구

Abstract - In this paper, we analyzed the optimal configuration of protection wire that have been installed in the electric railway power supply system. Protection wires are to suppress the ground potential rise when the short circuit fault between contact wire-rail(C-F), and protect the electronics equipments(signalling and communication) that are facility the wayside. The role of protection wires must be feed back quickly the fault current to the substation when a short circuit fault occurs. In this paper, we proposed that only one line to install the protection wire. Comparing how to newly proposed and existing system, most of the performance is similar. The reason is that most of the current flowing in the protection wire near the location where the fault occurred. There is no problem even if in one line for human safe and the low impedance of the return circuit in dimension to ensure the safety of the facility during the fault. To ensure safety during an fault occurs, it is sufficient even by one line. But, In the protection wire of facilities planning it is necessary to design taking into account the potential utility.Key Words : High speed catenary system, Overhead contact lines, Fault protection wire, Current capacity, Mechanical strength†Corresponding Author : Woomin Electric Corporation, KoreaE-mail : hl4gzn@hanmail.net* Division of Railroad System Engineering, Woosong University, Daejeon, KoreaReceived : October 7, 2015; Accepted : November 25, 2015

Regenerative Energy Control of DC Electric Railway Based on Solid State Transformer

Regenerative energies are generated by regenerative braking of train. Regenerative energies might cause the problem of power quality such as the voltage drop and malfunction of the power conversion device in the electric railway system. For these reasons, many researches have studied to solve these problems. In this paper, we modeled DC electric railway system based on the solid state transformer that is composed of voltage source converter (VSC) and bi-directional DC-DC converter for controlling the regenerative energy. In order to verify the performance of the proposed electric railway system, electric railway system is modeled by using real time simulator OP5600. In addition, the controller of solid state transformer is implemented by using DSP, TMS320F28335.

A Sprague Invention: Multiple Unit Train Control [History

The group of 12 men gathering in the basement of the 1892 construction site didn't look like anything special. They just seemed like some hard-working types in rough suspendered pants and with a hat or cap on their heads. But they were special since some of them had been part of the team that had completed the world's first major commercially successful electric street railway system in Richmond, Virginia, four years earlier. Now part of the Sprague Electric Elevator Company, they were facing a new challenge in the brand new Postal Telegraph building rising in New York City at the intersection of Murray Street and Broadway. Their task was to install what would be, at that time, the most advanced bank of electric elevators in the world, two express and four locals rising 14 stories above the city.

FMECA를 통한 전차선로 가선시스템의 신뢰도 분석에 관한 연구

The reliability of catenary system is very important for uninterrupted train operation as it supplies electric power to train without redundant facilities. This paper provides a systematic approach to the reliability analysis of the catenary system based on FMECA procedures defined by global standards such as MIL Std 1692a and IEC 60812. Field failure data collected from the operation and maintenance of high-speed railway catenary system for 9 years are used to derive critical failure modes and to evaluate the criticality of the failure modes. Evaluation of the criticality are carried out by quantitative procedures defined by MIL Std 1692a and by criticality matrix defined by IEC 60812. FMECA results suggests that three critical failure modes should be checked carefully during maintenance work, which include strand break of dropper and voltage equalizing wire, power supply failure of feeder. Maintenance procedure of catenary system in order of importance is suggested too. These results can be applied to maintenance planning and design of catenary system to improve the reliability of electric railway system.

Optimal Sizing of Energy Storage for Regenerative Braking in Electric Railway Systems

<?Pub Dtl=""?> The problem of optimally sizing hybrid energy storage systems (HESS) installed in electric railway systems, considering the effect of regenerative braking is studied in this paper. HESSs combine traditional batteries and newly developed ultracapacitors, taking advantage of the high energy capacity of batteries and of the flexibility and ability to capture high power density of ultracapacitors. A novel mixed integer linear programming formulation that includes the counting of battery cycles is presented. Some particularities of battery operation are included in the model, like the dependence of its performance on the number of cycles and the depth of discharge (DOD). Results are reported first for a illustrative case study, allowing us to perform sensitivity studies for several parameters; results are also reported and for a larger case, closely resembling the problem faced by railway energy systems planners and operators.

열차운행 시격 변경에 따른 트램 급전계통 해석

In order to understand phenomenon of the electric railway power feeding system in the construction planning step, analysis of the overall system including electric characteristic of electric railway power feeding system, train running characteristic and power consumption pattern and train operation plan and gradients of railroad and curve radius is required.BR This paper study the feeder system by analysis of comprehensive system according to train operation plans, line impedance, running characteristic of train, electrical properties of the feeder system. In order to understand phenomenon to the feeder system of tram exactly regarding export of the field railroad preceeding actively recently.

전압형 컨버터와 EDLC의 협조 제어에 의한 직류전기철도 회생에너지 이용률 및 전압 제어 능력 향상

In the DC electric railway system, the effective use of regenerative break energy is an important issue. Since regenerative break energy causes voltage rise or drop in the system, it should be also solved effectively. To solve the problems, applying electric double layer capacitor (EDLC) or voltage source converter (VSC) to the DC electric railway system has been studying. In this paper, the coordination of EDLC and VSC is proposed to solve the problem effectively with its coordinated control algorithm. The proposed method is tested to show its feasibility using Matlab/Simulink.

Reduction of the Contact Corrosion on the Electrical Networks by Applying Bimetallics

The contact corrosion phenomena occuring at the electrical networks when two dissimilar metallic parts are connected to each other causes serious technical and economical problems. One possible solution to reduce the contact corrosion is the application of properly prepared bimetallics. The paper introduces the explosive cladding technique which can be successfully applied for manufacturing bimetallics matched to the given electrical circuit furthermore application possibilities of the explosively cladded bimetallics at electrical networks, railway systems and vehicles.

직류도시철도 시스템에서 저장장치 단위 용량 당 에너지 절감 효과 분석 연구

직류도시철도 시스템에서 저장장치 단위 용량 당 에너지 절감 효과 분석 연구

Characteristic Analysis of DC Electric Railway Systems with Superconducting Power Cables Connecting Power Substations

The application of superconducting power cables to DC electric railway systems has been studied. It could leads to an effective use of regenerative brake, improved energy efficiency, effective load sharing among the substations, etc. In this study, an electric circuit model of a DC feeding system is built and numerical simulation is carried out using MATLAB-Simulink software. A modified electric circuit model with an AC power grid connection taken into account is also created to simulate the influence of the grid connection. The analyses have proved that a certain amount of energy can be conserved by introducing superconducting cables, and that electric load distribution and concentration among the substations depend on the substation output voltage distribution.

VSC-Based MVDC Railway Electrification System

This paper proposes a new railway electrification system in which the voltage-source converter (VSC) becomes the basic building block. This will allow existing railways, comprising several ac and dc subsystems, to be transformed into simpler medium-voltage dc (MVDC) multiterminal power systems feeding mobile loads. Moreover, the VSC-based unified scheme will substantially facilitate the connectivity among otherwise heterogeneous railway systems, while the integration of distributed generation and storage is achieved in a straightforward fashion. In addition to the general MVDC architecture, details are provided about the dc catenary layout, dual-voltage locomotive configurations, and dc-dc links between urban and long-distance railways. The need for a supervisory control system, and its role in coordinating local VSC controllers, so that the resulting power flows are optimized while the catenary voltage is kept within limits, are discussed. The proposed railway electrification paradigm is compared with the standard 25-kV, ac electrification system by means of a real case study.

회생에너지를 이용한 도시철도 전력관리시스템 구축에 관한 연구

For the large scale of electricity consumer, since the price for the electricity consumption depends on the peak power, the issue for peak power reduction have been being studied widely. Electric railway systems, which is one of the most representative large scale of loads, also has assignment to reduce the peak power since they have high peak power and low energy consumption load characteristics. In the aspect of the economic operation through reduction of peak power, this paper proposes a novel algorithm for power management system in electric railway systems using energy storage.