Some facts and figures of Indian Railways

데버랜전고팔(Devarajan Gopal),노영환(Lho Young Hwan),김윤호(Kim Yoon Ho) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-

Indian Railways runs about 10,000 trains and carries 15 million people daily. Today Indian Railways run efficiently and makes a modest profit in spite of reducing the passenger and freight fares. As Indian Railways has a long history, a brief introduction will be given. Indian Railways has three different gauges (Narrow, Meter and Broad) during British rule and now it is converging to broad gauge in a phased manner. The details will be addressed. As Indian terrain is not that much favorable to Rails. Evolution of rail engines, coaches / wagons which are all manufactured in India are given in details. As India is attaining self sufficiency in almost all fields of Science and Technology, various production units, research units, Journals etc are also discussed. Statistics pertaining to railways both technical and commercial are addressed.

Rail Road Electric Traction System

데버랜전고팔(Devarajan Gopal),노영환(Lho Young Hwan),김윤호(Kim Yoon Ho) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-

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.

Indian Railway Locomotives with IGBT Based Traction Control Converter

데버랜전고팔(Devarajan Gopal),노영환(Lho Young Hwan),김윤호(Kim Yoon Ho) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

Standard Gate Turn Off (GTO) Thyristor drive technology results in inhomogeneous turn-on and turn-off transients which in turn needs costly dv/dt and di/dt snubber circuits. Added to this GTO is bulky in size, needs external cooling, slower switching time etc. The development of high voltage Insulated Gate Bipolar Transistor (IGBT) have given new device advantage in the areas where they compete with conventional GTO technology. Indian Railway has developed first IGBT based traction converter and was commissioned in November 2006. Some of the supremacy of IGBT are smaller in size, no external cooling is required, built in power supply which enhances reliability, lower switching losses which leads to higher efficiency, reduced gate drive, high frequency operation in real time etc. These advantages are highlighted along with IGBT Traction system in operation.

Traction IGBT Modules Design Issues and Precautions

데버랜전고팔(Devarajan Gopal),노영환(Lho Young Hwan),김윤호(Kim Yoon Ho) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-

IGBT modules are designed for low loss, rugged for all environments and user friendly. Low on state saturation voltage with high switching speed is the primary concerns. In this paper selection of IGBT, module ratings and characteristics are discussed. The IGBT design topic of protection against over voltage and over current are covered. Emphasis on turn off switching, short circuit switching and necessary precautions are dealt. Selection of IGBT device, gate drive power, and its lay out considerations are covered in detail.

Electrical Characteristics of Catenary

데버랜전고팔(Devarajan Gopal),노영환(Lho Young Hwan),김윤호(Kim Yoon Ho) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

In this paper, the basic requirements of catenary in railroad traction is explained. Three different types of catenary suspension systems for different terrains, environments and high speed / low speed trains are presented. The essential requirements of catenary such as reliability, cost effectiveness, maintenance and ruggedness requirements are discussed. The catenary materials and safety problems associated in it are dealt.

RK-Butcher알고리듬의 사용에 의한 주기적 진동 문제의 수치적 시뮬레이션

박대철,Devarajan Gopal,V. Murugesh 한국융합신호처리학회 2008 융합신호처리학회 논문지 (JISPS) Vol.9 No.1

In this paper, Runge-Kutta (RK)-Butcher algorithm is proposed to study the periodic and oscillatory problems. Simulation results obtained using RK-Butcher algorithms and the classical fourth order Runge-Kutta (RK(4)) methods are compared with the exact solutions of a few periodic and oscillatory problems to confirm the performance of the proposed algorithm. The simulation results from RK-Butcher algorithms are always found to be very close to the exact solutions of these problems. Further, it is found that the RK-Butcher algorithm is superior when compared to RK(4) methods in terms of accuracy. The RK-Butcher algorithm can be easily implemented in a programming language and a more accurate solution may be obtained for any length of time. RK-Butcher algorithm is applicable as a good numerical algorithm for studying the problems of orbit and two body as it gives the nearly identical solutions. 본 논문은 주기적 진동 문제를 연구하기 위해 Runge-Kutta(RK)-Butcher 알고리듬이 소개되었다. RK-Butcher 알고리듬을 사용하여 얻어진 시뮬레이션 결과와 고전적인 4차 RK(4) 방법을 통해 얻은 결과들을 제안한 알고리듬의 성능을 확인하기 위하여 몇몇 주기적 진동 문제들의 정확한 해와 비교하였다. RK-Butcher 알고리듬의 시뮬레이션 결과는 항상 문제의 정확한 해 RK(4) 방법보다 더 근접한 결과를 줌이 확인되었다. 정확도 측면에서 RK-Butcher 알고리듬이 RK(4) 방법과 비교해볼 때 우수함을 알 수 있다. 제안한 RK-Butcher 알고리듬은 프로그램 언어로 쉽게 구현할 수 있으며 임의 시간에 종료해도 훌륭한 근사적인 해를 얻을 수 있다. RK-Butcher 알고리듬은 짧은 시간내에 이상적인 정확한 해에 근접한 결과를 주기 때문에 궤도 와 두 물체의 문제를 연구하는데 훌륭한 수치 알고리듬으로 적용가능하다.

Voltage Sag and Swell Estimation Using ANFIS for Power System Applications

N. Malmurugan,Devarajan Gopal,Young Hwan Lho 한국철도학회 2013 한국철도학회논문집 Vol.16 No.4

Voltage Sag and Swell Estimation Using ANFIS for Power System Applications

Malmurugan, N.,Gopal, Devarajan,Lho, Young Hwan The Korean Society for Railway 2013 한국철도학회논문집 Vol.16 No.4

Power quality is a term that is now extensively used in power systems applications, and in this context the voltage, current, and phase angle are discussed widely. In particular, different algorithms that are capable of detecting the voltage sag and swell information in a real time environment have been proposed and developed. Voltage sag and swell play an important role in determining the stability, quality, and operation of a power system. This paper presents ANFIS (Adaptive Network based Fuzzy Inference System) models with different membership functions to build the voltage shape with the knowledge of known system parameters, and detect voltage sag and swell accurately. The performance of each method has been compared with each other/other methods to determine the effectiveness of the different models, and the results are presented.

Numerical Simulation of Periodic and Oscillatory Problems by Using RK-Butcher Algorithms

Park, Dae-Chul,Gopal, Devarajan,Murugesh, V. The Korea Institute of Convergence Signal Processi 2008 융합신호처리학회 논문지 (JISPS) Vol.9 No.1

본 논문은 주기적 진동 문제를 연구하기 위해 Runge-Kutta(RK)-Butcher 알고리듬이 소개되었다. RK-Butcher 알고리듬을 사용하여 얻어진 시뮬레이션 결과와 고전적인 4차 RK(4) 방법을 통해 얻은 결과들을 제안한 알고리듬의 성능을 확인하기 위하여 몇몇 주기적 진동 문제들의 정확한 해와 비교하였다. RK-Butcher 알고리듬의 시뮬레이션 결과는 항상 문제의 정확한 해 RK(4) 방법보다 더 근접한 결과를 줌이 확인되었다. 정확도 측면에서 RK-Butcher 알고리듬이 RK(4) 방법과 비교해볼 때 우수함을 알 수 있다. 제안한 RK-Butcher 알고리듬은 프로그램 언어로 쉽게 구현할 수 있으며 임의 시간에 종료해도 훌륭한 근사적인 해를 얻을 수 있다. RK-Butcher 알고리듬은 짧은 시간내에 이상적인 정확한 해에 근접한 결과를 주기 때문에 궤도 와 두 물체의 문제를 연구하는데 훌륭한 수치 알고리듬으로 적용 가능하다. In this paper, Runge-Kutta (RK)-Butcher algorithm is proposed to study the periodic and oscillatory problems. Simulation results obtained using RK-Butcher algorithms and the classical fourth order Runge-Kutta (RK(4)) methods are compared with the exact solutions of a few periodic and oscillatory problems to confirm the performance of the proposed algorithm. The simulation results from RK-Butcher algorithms are always found to be very close to the exact solutions of these problems. Further, it is found that the RK-Butcher algorithm is superior when compared to RK(4) methods in terms of accuracy. The RK-Butcher algorithm can be easily implemented in a programming language and a more accurate solution may be obtained for any length of time. RK-Butcher algorithm is applicable as a good numerical algorithm for studying the problems of orbit and two body as it gives the nearly identical solutions.

Error Free Butcher Algorithms for Linear Electrical Circuits

K. Murugesan,N.P. Gopalan,Devarajan Gopal 한국전자통신연구원 2005 ETRI Journal Vol.27 No.2

In this paper, an error-free Butcher algorithm is introduced to study the singular system of a linear electrical circuit for time invariant and time varying cases. The discrete solutions obtained using Runge-Kutta (RK)- Butcher algorithms are compared with the exact solutions of the electrical circuit problem and are found to be very accurate. Stability regions for the single term Walsh series (STWS) method and the RK-Butcher algorithm are presented. Error graphs for inductor currents and capacitor voltages are presented in a graphical form to show the efficiency of the RK-Butcher algorithm. This RK-Butcher algorithm can be easily implemented in a digital computer for any singular system of electrical circuits.