• Title/Summary/Keyword: AC Electric Railway Systems

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A Study on DC Power Regeneration for Railway using Parallel PWM Converter (병렬 PWM 컨버터를 이용한 철도차량 직류 전력 회생장치에 관한 연구)

  • Lee Jong-Moo;Jang Su-jin;Song Sang-Hun;Won Chung-Yuen;Ahn Kyu-Bok;Lee Joon-Gee
    • Proceedings of the KIPE Conference
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    • 2004.07b
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    • pp.524-527
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    • 2004
  • When the electric tractions are stopped or driven through the falling slope way, it occured to surplus energy in the DC power line. At present, these energy are exhausted by breaking-system. The converter is not only capable of feeding energy back into the AC source during excessive regeneration. It is issued for this surplus energy regenerating system. These systems are faced with high voltage and high power for railway DC power regeneration. This paper proposed a parallel PWM converter how to solve these problem.

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A Study on a Current Control Based on Model Prediction for AC Electric Railway Inbalance Compensation Device (교류전력 불평형 보상장치용 모델예측기반 전류제어 연구)

  • Lee, Jeonghyeon;Jo, Jongmin;Shin, Changhoon;Lee, Taehoon;Cha, Hanju
    • The Transactions of the Korean Institute of Power Electronics
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    • v.25 no.6
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    • pp.490-495
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    • 2020
  • The power loss of large-capacity systems using single-phase inverters has attracted considerable attention. In this study, optimal switching sequence model prediction control at a low switching frequency is proposed to reduce the power loss in a high-power inverter system, and a compensation method that can be utilized for model prediction control is developed to reduce errors in accordance with sampling values. When a three-level, single-phase inverter using a switching frequency of 600 Hz and a sampling frequency of 12 kHz is adopted, the power factor is improved from 0.95 to 0.99 through 3 kW active power control. The performance of the controller is also verified.

Harmonics Assessment for an Electric Railroad Feeding System using Moments Matching Method (모멘트 정합 방법(Moment Matching Method)을 이용한 전기철도 급전시스템의 고조파 평가)

  • Lee, Jun-Kyong;Lee, Seung-Hyuk;Kim, Jin-O
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.1
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    • pp.1-7
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    • 2007
  • Generally, an electric railroad feeding system has many problems due to the different characteristics in contrast with a load of general three-phase AC electric power system. One of them is harmonics problem caused by the switching device existing in the feeding system, and moreover, the time-varying dynamic loads of rail way is inherently another cause to increase this harmonics problem. In Korea power systems, the electric railroad feeding system is directly supplied from the substation of KEPCO. Therefore, if voltages fluctuation or unbalanced voltages are created by the voltage and current distortion or voltage drop during operation, it affects directly the source of supply. The trainloads of electric railway system have non-periodic but iterative harmonic characteristics as operating condition, because the electric characteristic of the electric railroad feeding system is changed by physical conditions of the each trainload. According to the traditional study, the estimation of harmonics has been performed by deterministic way using the steady state data at the specific time. This method is easy to analyze harmonics, but it has limits in some cases which needs an assessment of dynamic load and reliability. Therefore, this paper proposes the probabilistic estimation method, moments matching method(MW) in order to overcome the drawback of deterministic method. In this paper, distributions for each harmonics are convolved to obtain the moments and cumulants of TDD(Total Demand Distortion), and this can be generalized for any number of trains. For the case study, the electric railway system of LAT(Intra Airport Transit) in Incheon International Airport is modeled using PSCAD/EMTDC dynamic simulator. The raw data of harmonics for the moments matching method is acquired from simulation of the LAT model.

Analysis of Current Collection Performance using Real-time Measurement of Current for Overhead Contact Line on the Track-side (선로변 전차선과 조가선의 전류를 이용한 집전성능 분석 기술)

  • Park, Young;Shin, Seung-Kwon;Lee, Kiwon;Kim, Jaemoon;Kim, Wonha
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.4
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    • pp.573-576
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    • 2013
  • 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.

Rail Road Electric Traction System (철도 전기 시스템)

  • Gopal, Devarajan;Lho, Young-Hwan;Kim, Yoon-Ho
    • Proceedings of the KSR Conference
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    • 2006.11b
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    • pp.646-658
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    • 2006
  • In this paper, the details of electric traction voltages which are widely used for metro and mainline trains are presented. The problems encountered in catenaries, pressure of the pantograph pan, catenary contact cross sectional area, materials etc are well covered. Catenary height from the rail for main line, bridges, sheds etc is discussed. The catenary running details and switching of one catenary to another are explained. The dead zones in 3 phase grid as well as in DC are presented here. The pantograph structure, blades, shoes etc. for AC/DC EMUs are dealt. The schematic diagram for electrification systems used for railways are given and explained with typical electrical parameters of Indian Railways.

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A Development Plan for Core System of Urban Transit based on System Engineering Process (시스템엔지니어링 수명주기를 고려한 도시철도 핵심장치 개발 전략)

  • Han, Seok-Youn;Kim, Jin-Ho;An, Tae-Ki;Lee, Woo-Dong;Shin, Won-Sik
    • Proceedings of the KSR Conference
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    • 2008.11b
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    • pp.2005-2013
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    • 2008
  • Urban transit is a large scaled complex system which combines rolling stocks, power supply, signal communications, tracks & stations etc. KRRI develops nine key devices since July, 2007 as a part of the second phase of project on the standardization of urban rail transit system, which include information-communication system, station facilities, AC-DC current electric power system in urban transit. We promote the project under two directions, i.e. user-customer oriented standardization and strategic standardization for leading technologies in urban transit. In this paper, we present development plan of these key systems in view of system life cycle based on system engineering standards KSX ISO/IEC 15288 which supplies the common fundamental frame to describe the life cycle of artificial systems. System engineering process of KSX ISO/IEC 15288 are helpful to efficiently develop those key devices, although it is difficult to apply the standard identically to the key devices with the varieties and characteristics.

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A Study on the Design of Controller for Speed Control of the Induction Motor in the Train Propulsion System-2 (열차추진시스템에서 유도전동기의 속도제어를 위한 제어기 설계에 대한 연구-2)

  • Lee, Jung-Ho;Kim, Min-Seok;Lee, Jong-Woo
    • Journal of the Korean Society for Railway
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    • v.13 no.2
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    • pp.166-172
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    • 2010
  • Currently, vector control is used for speed control of trains because induction motor has high performance is installed in Electric railroad systems. Also, control of the induction motor is possible through various methods by developing inverters and control theory. Presently, rolling stocks which use the induction motor are possible to brake trains by using AC motor. Therefore model of motor block and induction motor is needed to adapt various methods. There is Variable Voltage Variable Frequency (VVVF) as the control method of the induction motor. The torque and speed is controlled in the VVVF. The propulsion system model in the electric railroad has many sub-systems. So, the analysis of performance of the speed control is very complex. In this paper, simulation models are suggested by using Matlab/Simulink in the speed control characteristic. On the basis of the simulation models, the response to disturbance input is analyzed about the load. Also, the current, speed and flux control model are proposed to analyze the speed control characteristic in the train propulsion system.

Controllable Harmonic Generating Method for Harmonic Impedance Measurement of Traction Power Supply Systems Based on Phase Shifted PWM

  • Liu, Qiujiang;Wu, Mingli;Li, Jing;Zhang, Junqi
    • Journal of Power Electronics
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    • v.18 no.4
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    • pp.1140-1153
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    • 2018
  • The harmonic impedance characteristic of a traction power supply system (TPSS) is necessary for taking actions to suppress the high-order harmonic resonances caused by AC electric locomotives. This paper proposes a controllable harmonic generating method (CHGM) for measuring the TPSS harmonic impedance by injecting harmonic disturbances of different frequencies and amplitudes into the TPSS. This method applies phase shifted pulse-width modulation (PSPWM) and ensures that the undesired sideband harmonics can be negligible while the desired harmonic is both controllable and adjustable. Multiple harmonics can be emitted at the same time. The implementation of the method is also presented. Simulations are carried out to validate the performance of the proposed method. Finally, experimental results on a 5 H-bridge converters platform verified the effectiveness and feasibility of the proposed method.

A Study on the RAM Application of a Light Rail Transit Business, Ac-cording to the Technique Application in System Engineering (시스템엔지니어링 기법 적용에 따른 경량전철사업의 RAM적용에 관한 고찰)

  • Lee, Seong-Gwon;Min, Kyong-Se;Jeon, Seo-Tak;Jung, Kye-Young
    • Journal of the Korean Society of Systems Engineering
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    • v.7 no.2
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    • pp.13-19
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    • 2011
  • A LRT(Light Rail Transit) is one of the Future Urban Railway Development Project. The project's goal is to reduce a transportation congestion in the center of the city. New transportation is intensely required in order to overcome a limit of the ground transportation that is the existing public transportation, A LRT(Light Rail Transit) construction project to be based on an unmanned driving system is the large composition system that a vehicle, a signal, communication, electric, track etc. were organically integrated as echo-friendly urban transportation systems. It also put a huge budget, which is a large-scale infrastructure projects. It is international trend that Light Rail Transit projects apply a technique in System Engineering for a schedule, cost, quality elevations, and to approach in viewpoints of life-cycle from initial construction steps to operation, abolition. This paper intends to analyze RAM requirements taking into consideration ISO/IEC 15288 throughout life-cycle from concept, design, manufacture, operation and maintenance to the final phase, decommissioning, and the study seeks to suggest directions of efficient use to domestic LRT projects.

The High Power Active Filter System for Harmonic Compensation of 25kv Electric Railway (25kV 전기철도 고조파 보상을 위한 고전력 능동전력필터 시스템에 관한 연구)

  • Kim, Jae-Chul;Rho, Sung-Chan;Lee, Yoo-Kyung
    • Journal of the Korean Society for Railway
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    • v.9 no.6 s.37
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    • pp.761-765
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    • 2006
  • At present, harmonic currents cause serious problems in power conversion system using the semiconductor switching device. Also some of the conversion system provokes harmonic currents against to the main power supply system and causes hindrances for the system. Main power impedance of the traditional LC passive filter method, influences on the filter characteristics and amplifies the harmonics when resonance phenomenon is occurred. And the traditional existing 2 level inverter systems show the limit in capacity of voltage and current in case of occurring sudden load change. So, to solve this problem active filter which uses cascaded H-bridge multi level inverter has been designed and ex-filter system circuits were totally investigated. With multi level active filtering system not only the size of filter but also the size of filter for transformer can be reduced by half and so as to the weight, while the capacity of inverter can be double sized and wave forms can be compensated exactly and precisely. Also by the benefit of the increase in rating capacity, the various currents owing to the load fluctuation can be dealt more steadily. In order to simulate the wave form of harmonics based on the measured data on the AC 25kV high speed Domestic Commercial railway, it was simulated with PSCAD/EMTDC and PSIM. Based on the results of this demonstration, the power supply system and inverter system would be more stable and also promoting its efficiency.