• Title/Summary/Keyword: line source

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A study of the harmonics evaluation in the test track of Korea High Speed Rail (경부고속철도 시험선구 고조파 예측에 관한 연구)

  • 김길상;오광해;권삼영;이태형
    • Proceedings of the KSR Conference
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    • 1998.11a
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    • pp.241-248
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    • 1998
  • The purpose of this study is to evaluate the harmonics generated from Korea High Speed Rail's trainset and to analyze the effect on the KEPCO power system. This study focuses on the test track of the high speed rail and analyzes 154㎸ transmission line, scott transformer, autotransformer and 27,5㎸ line. The trainset is modeled as a harmonic source attached to the catenary line of the test track. Then, harmonic distortion is calculated. This distortion is compared with the KEPCO's regulations in relation to harmonic.

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Voltage Control Strategy of new 3-phase Line-Interactive UPS System using AC Line Reactor and Parallel-Series Active Filter (AC 라인 리액터와 병렬 및 직렬 능동필터를 가지는 새로운 3상 Line-Interactive UPS 시스템의 전압제어 방식)

  • Ji, Jun-Keun;Kim, Jang-Hwan;Sul, Seung-Ki
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.3
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    • pp.538-546
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    • 2007
  • A new 3-phase line-interactive UPS(Uninterruptible Power Supply) system with parallel-series active power-line conditioning capability using AC line reactor and two four-leg PWM VSCs(Voltage Source Converters) was introduced recently. In this paper, the strategy of voltage control in suggested UPS system is explained. The objective of proposed voltage controllers in parallel(shunt) and series PWM VSC is to guarantee satisfactory characteristics in steady state and transient state. Therefore the experimental results to prototype UPS system having power rating of 60kVA is shown to prove the verification of voltage control strategy.

Analysis of Electromagnetic Field Around Distribution Line (배전선로 주변에서의 전자계 분포 해석)

  • Kwon, Myung-Rak
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.30 no.10
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    • pp.672-676
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    • 2017
  • Electrical energy is playing an increasingly vital role as the primary energy source in everyday life. With the increase in electric power consumption, power facilities are under an increasing stress and must operate at a high capacity. Consequently, the demand for electric power cables in power transmission and distribution lines is rapidly increasing. Underground distribution lines have been steadily replacing the aboveground lines owing to the increase in electric power demand and the need to increase the supply voltage. In addition to line damage, worker safety is of primary concern in this type of underground infrastructure. In this study, to improve the safety of workers dealing with underground transmission lines, we analyzed the electromagnetic field generated around the distribution line and determined the basic criteria for developing a device that can detect a live underground line.

On-line Insulation Diagnostic by PD Monitoring Field Practical of UHF Technique for On-line PD Monitoring (UHF 기술을 이용한 온라인 부분방전 모니터링)

  • Oh, Yong;Choi, Yong-Sung;Hwang, Jong-Sun;Lee, Kyung-Sup
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.2
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    • pp.176-180
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    • 2008
  • A field-oriented UHF system for on-line PD monitoring of transformers is designed, which has been installed inside the oil tank of transformer in a substation by two ways: on-line installing mode through the oil-valve and pre-installing mode through the man hole/hand hole cover. This system has successfully captured long intermittent discharge signals that hadn't been detected through conventional techniques, and solved the problem successfully. The results demonstrate that UHF technique has great advantages for on-line PD monitoring of transformers. By adopting the peak detection technique, it becomes easy and effective for the transplantation of the phase-resolved pattern recognition technique from conventional method to UHF method, and then to realize continuous on-line monitoring, source characterization and trending analysis.

Development of the Method Estimating Sections Occurring Intensive PM10 in a Subway Tunnel (For the South Section (Cheongdam~Jangseungbaegi) of Subway Line 7 in Seoul) (지하철 터널의 미세먼지 집중 발생구간 추정방법 개발 (서울 지하철 7호선 남단구간 (청담역~장승배기역) 을 대상으로))

  • Park, Jong-Heon;Park, Jae-Cheol;Eum, Seong-Jik
    • Journal of Korean Society of Transportation
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    • v.28 no.6
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    • pp.121-131
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    • 2010
  • To effectively reduce PM10 generated in concourses and platforms of subway stations, a research is being conducted to find the PM10 source. The main source of PM10 in subway stations was PM10 generated in the main line tunnels, which was generated in proportion to the frequency of the train operation. Each amount of the PM10 generated when the train was operated once, was constant regardless of the time. On the assumption that the PM10 level in a tunnel of a line is a sum of newly generated amount of dust when the subway passes and the amount carried from the adjacent stations by the wind generated from the subway rolling stocks, the method which estimates the intensive PM10 occurring section was developed and applied to the 12 stations between Cheongdam and Jangseungbaegi in Seoul Subway Line 7.

Measurement of Ceiling Temperature in Tunnel for Heights and Fire Sizes of Fire Source (화원의 높이 및 화재크기별 터널 천장온도 측정 실험)

  • Park, Won-Hee
    • The KSFM Journal of Fluid Machinery
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    • v.18 no.1
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    • pp.5-10
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    • 2015
  • The "Ondong tunnel" is not used now where is one of the tunnels in the Janghang line which is from Cheonan to Iksan. The length of the tunnel is 214 m. The location of the fire source is center of the tunnel and the pool fire with heptane is for the fire source. Tests are carried out for the various fire sizes, the height and obstructed/open condition of the fire source. Temperature on the top of the tunnel is measured. Even if the fire size is same, the maximum temperature on the ceiling of the tunnel for the elevated fire source is very larger than the maximum for the ground fire source. As the fire size is lager the maximum temperature on the ceiling is higher. These test results can be very useful for design and guidelines of fire detectors in tunnels.

Instantaneous torque control of induction motor with line-to-line voltage modulation on the variable load. (가변 부하시 선간전압 변조방식을 이용한 유도전동기의 순시 Torque 제어)

  • No, J.H.;Woo, J.I.;Lee, H.W.
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.645-648
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    • 1991
  • In conventional sinusoidal wave PWM control, torque oscillation is a problem on account of harmonic component. This paper deals with the choice of line-to-line voltage modulation method, which is effective in using DC(direct current) source voltage and in controlling harmonic oscillation, and the pattern to reduce swiching loss through 1/3 pause of switching interral. So, this paper deals with valid realization of harmonic component and high torque response on variable load by simulation and experiments to compensate occurring problems when line-to-line modulation are applied to PWM inverter.

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On-line PD Monitoring Using UHF Technique (UHF 가술을 이용한 온라인 PD 모니터링)

  • Choi, Yong-Sung;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.04c
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    • pp.115-118
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    • 2008
  • A field-oriented UHF system for on-line PD monitoring of transformers. is designed, which has been installed inside the oil tank of a transformer by two ways: on-line installing mode through the oil-valve and pre-installing mode through the man hole/hand hole cover. This system has successfully captured long intermittent discharge signals that hadn't been detected through conventional techniques, and solved the problem successfully. The results demonstrate that UHF technique has great advantages for on-line PD monitoring of transformers. By adopting the peak detection technique, it becomes easy and effective for the transplantation of the phase-resolved pattern recognition technique from conventional method to UHF method, and then to realize continuous on-line monitoring, source characterization and trending analysis.

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The Estimation of Curvature Deformation of Steel Plates in Water Cooling Process after Line Heating (선상 가열시 수냉 효과를 고려한 강판의 변형 추정에 관한 연구)

  • HwangBo, Hyeok;Yang, Park-Dal-Chi
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2006.11a
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    • pp.209-212
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    • 2006
  • Line heating with water cooling is generally adapted process in the shipyards for the forming hull surface. The purpose of this paper is to develop a model of thermal deformation in water cooling process after the line heating. In order to simulate the cooling process, heat transfer analysis was performed by assuming the effects of water cooling as a negative heat-source. Experiment for the line heating with water cooling was performed for 9 models of plates in order to verify the cooling model. By using the suggested model for the water cooling process, it could be observed that the present method predict the plate deformations in the line heating more accurately.

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