• Title/Summary/Keyword: Electrical Substation System

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A Regeneration Inverter for Traction Applications with a Active Power Filter (능동전력필터를 가진 지하철 회생인버터 시스템)

  • Won, Chung-Yuen;Jang, Su-Jin;Kim, Yuen-Chung;Lee, Byoung-Kuk;Bae, Chang-Hwan;Kim, Yong-Ki
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.5
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    • pp.25-32
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    • 2006
  • This paper proposes a regeneration inverter system, which can regenerate the excessive power form do bus line to ac source for traction system. The proposed regeneration inverter system for dc traction can reduce harmonics which are included to ac current source. The regeneration inverter is operated as two modes. In the regeneration inverter mode, it can recycle regenerative energy caused by decelerating tractions and in the active power filter mode, it can compensate harmonic distortion produced by the rectifier substation. In this paper, the regeneration inverter uses PWM DC/AC inverter algorithm and the active power filter uses p-q theory. From the informative simulation and experimental results, which are performed wiith a prototype rated 3.7[kw], it can expected that the proposed system can be effectively applied in the real traction system rated 100[kw].

Power Quality Analysis of Jeju System Considering HVDC Overhaul and Wind Turbines (HVDC Overhaul 및 풍력발전을 고려한 제주계통 전력품질 분석)

  • Chae, Woo-Kyu;Yoon, Gi-Gab;Kim, Jae-Eon;Han, Ji-Han
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.1
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    • pp.132-140
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    • 2008
  • Power system of Jeju is interconnected to the mainland using HVDC and that is also interconnected two wind farms. Control of Jeju power system will be difficult if HVDC is disconnected or HVDC is overhauled under large scale wind farms interconnected. We measured and analysed the power quality of two substation and two wind farms to assess that wind farms and HVDC overhaul have an effect on Jeju system or not during the HVDC overhaul. We found that the frequency of Jeju system is very unstable and the voltage distortion excess the limitation. Harmonic currents of wind farms flew into Jeju system in proportion to the power of wind turbine. And the voltage of nearby distribution line was distorted by power of wind turbine when the amount is more that 3,000[kW].

Development of a Digital System for Protection and Control of a Substation Part 2 - Development of Fiber Optic Network (변전소의 보호.제어를 위한 디지탈 시스템 개발 PART 2 - 광 통신망 개발)

  • Kwon, W.H.;Park, S.H.;Kim, M.J.;Lee, Y.I.;Park, H.K.;Moon, Y.S.;Yoon, M.C.;Kim, I.D.;Lee, J.H.
    • Proceedings of the KIEE Conference
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    • 1992.07a
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    • pp.362-364
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    • 1992
  • In this paper, the development of a fiber optic network for an integrated digital protection relay system is described. The structure of the developed network is determined to loosen the optic requirements and to have good extensibility while providing sufficient functions for protection and control for substations. The network has a hierarchical structure with two levels. The upper level handles data for monitoring and control of the system with star topology. The lower level manages the real time data for bus protection with one-to-one connections. Communication flows of each level are described. The HDLC is employed as the network protocol.

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A study on the development of substation power system simulator for education and training (변전소 전력계통 교육용 SIMULATOR 개발에 관한 연구)

  • Baik S. D.;Kim S. K.;Lee J. H.;Lee S. C.
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.67-69
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    • 2004
  • This thesis attempts to investigate and analyze the structure of educational simulation devices implemented thus far. conducting a close analysis of their strengths and weaknesses. On this basis the author Presents and implements a new method of simulation, and continuously upgrades it for increased stability and convenience. The most important aspects of the educational simulation device described in this thesis are: first removing the editing function (scenarios. single line diagrams, and point DB), which the instructor finds time-consuming and inconvenient to use; second, developing and installing the program so as to calculate electric power flow that can measure fluctuations measurements after changing the system status; and third. implementing a Client/server mode to build a system that will make it possible to train many people at a time in remote locations. When compared to simulation devices of the Psst. the greatest differences are that algorithm-based scenarios make scenario inputs unnecessary. and that the amount of work required for the point DB and single line diagrams were minimized.

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Approximate Model for Peak Demand Power Computation in Metro Railway with DC Rectifiers (DC정류기를 갖는 도시철도의 최대수요전력 산출 근사모델)

  • Kim, Han-Su;Kwon, Oh-Kyu
    • Journal of the Korean Society for Railway
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    • v.16 no.5
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    • pp.372-378
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    • 2013
  • This paper presents an approximate model for computing the peak demand power in a metro railway system. The peak demand of substations can be calculated using the current vector iteration method. But the existing method requires many repeated calculations to determine the peak demand power, which makes it difficult to apply to the real-time peak power control problem. In this paper, we assume that none of the conditions vary except source impedance and make an approximate model for rapid calculation based on changes in the impedance of the power substation. The proposed model result is approximately the same as the existing model, which is demonstrated through simulation.

A Study on the Electromagnetic Transients at Switching Capacitor Banks in a Electric Distribution Electric Power Distribution Substation (배전변전소에서 캐패시터 뱅크 투입시 일어나는 전자과도 현상에 관한 연구)

  • 김경철
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.16 no.1
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    • pp.92-99
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    • 2002
  • Transient in an electric distribution system are mainly generated by switching. This paper presents analysis of switching surge and means of limiting the voltage magnification transient for high voltage power systems by using the EDSA's EMTAP software package. One means of limiting the voltage magnification transient is to convert the end-user power factor contraction capacitor banks to harmonics filters. An inductance in series with the capacitor bank was used to decrease the transient voltage at the customer bus to acceptable levels. And also simulation results used the EDSA harmonics analysis program show the effect of harmonics reduction.

A Study on Variation of the Dynamic Characteristic of Supply Voltage According to the Track Environment and Spatial Distribution as Driving of Urban Transits (도시철도차량의 운행 선로환경 및 공간적 분포에 따른 공급전압 동특성 변화)

  • Kim, Yang-Su;Chang, Chin-Young;Lee, Ki-Sik;Koo, Kyung-Wan;Kim, Jae-Moon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.9
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    • pp.1380-1386
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    • 2012
  • It is important to consider supply voltage stability in case of design and construction of a substation at electric railway because a urban transit is operated by electricity and it is driven simultaneous in the same section. This paper study on variation of the dynamic characteristic of supply voltage according to the track environment and spatial distribution as driving of urban transits. Simulation tool, TOM(Train Operations Model) software is used to ensure stability of feeder system being used around the world. As results of simulation, voltage of the contact wire is in limits on driving operation diagram of urban transits. Also, it has confirmed that there is a correlation the phase current, depending on the speed of urban transit and track environment like vertical gradients and curve radius.

The Thermal Analysis of Pole Mount Mold Transformer with One-body Molding by Duct Condition (일체형 주상용 몰드변압기의 덕트에 따른 열해석 특성 연구)

  • Cho, Han-Goo;Lee, Un-Yong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.1135-1138
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    • 2003
  • The transformer is major equipment in power receiving and substation facilities. Necessary conditions required for the transformer are compactness, lightness, high reliability, economic advantages, and easy maintenance. The pole-mount transformer installed in distribution system is acting direct role in supply of electric power and it is electric power device should drive for long term. Most of modem transformer are oil-filled transformer and accident is happening considerable. The mold transformers have been widely used in underground substations in large building and have some advantages in comparison to oil-transformer, that is low fire risk, excellent environmental compatibility, compact size and high reliability. In addition, the application of mold transformer for outdoor is possible due to development of epoxy resin. The mold transformer generally has cooling duct between low voltage coil and high voltage coil. A mold transformer made by one body molding method has been developed for small size and low loss. One body molding transformer needs some cooling method because heat radiation between each winding is difficult. In this paper, The thermal analysis of pole mount mold transformer with one body molding by duct condition is investigated and the test result of temperature rise is compared with simulation data.

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Regeneration Inverter System for DC Traction with Hormonic Reduction Capability (고조파 저감 능력을 가진 직류전철 회생인버터 시스템)

  • Won, Chung-Yuen;Jang, Su-Jin;Kim, Yong-Ki;Bang, Hyo-Jin;Song, Sang-Hun;Ahn, Kyu-Bok
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.18 no.5
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    • pp.96-104
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    • 2004
  • This paper proposes a dc power regenerating systems, which can generate the excessive dc power from dc bus line to ac supply in substations for traction system The proposed regeneration inverter system for dc traction can be used as both an inverter and an active power filter(APF). As an regeneration inverter mode, it can recycle regenerative energy caused by decelerating tractions and as an active power filter mode, it can compensate for harmonic distortion produced by the rectifier substation. From the viewpoint of both power capacity and switching losses, the system is designed on the basis of three phase PWM inverters and composed of parallel inverters, output transformers, and an LCL filter.

A New Measurement Method of the Ground Resistance Using a Low-pass Filter in Energized Substations (지역필터를 이용한 수변전실 접지저항의 새로운 측정방법)

  • Lee, Bok-Hui;Eom, Ju-Hong;Lee, Seung-Chil;Kim, Seong-Won;An, Chang-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.8
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    • pp.387-393
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    • 2001
  • This paper describes an advanced measuring method and precise evaluation of the ground resistance for the grounding system of energized substations and power equipments. A grounding system of substations consists of all interconnected grounding connections of grounded conductors, neutral ground wires, underground conductors of distribution lines, cable shields, grounding terminals of equipments, and etc. It is very difficult to measure the accurate ground resistance of the grounding terminals of equipments, and etc. It is very difficult to measure the accurate ground resistance of the grounding system of high voltage energized substations because of harmonic components caused by switched power supplies or overloads. The conventional fall-of-potential method may be subject to big error if stray ground currents and potentials are present. In this work, to improve the precision in measurements of the ground resistance by eliminating the effects of harmonic components and stray currents and potentials, the investigations of the ground resistance measurement by using a low pass filter in a model energized grounding system were conducted. The accuracy of ground resistance mesurements was evaluated as a function of the ratio of the test signal to noise (S/N). The errors due to the proposed ground resistance measurement method were decreased with increasing S/N and were less than 5[%] as S/N is 10. The proposed ground resistance measurement method appears to be considerably more accurate than the conventional fall-of -potential method. It is allows cancellation of the parasitic resistance of energized grounding systems, to employ the measurement method that allows cancellation of the parasitic effects due to other circulating ground currents and ground potential rises in practical situations.

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