• Progress in Superconductivity
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• v.7 no.2
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• pp.162-166
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• 2006

We have proposed a 3 phase, 100 MVA, 154 kV class HTS transformer substituting for a 60 MVA conventional transformer. The power transformer of 154 kV class has a tertiary winding besides primary and secondary windings. So the HTS transformer should have the 3rd superconducting winding. In this paper, we designed conceptually the structure of the superconducting windings of a single phase 33 MVA transformer. The electrical characteristics of the HTS transformer such as % impedance and AC loss vary with the arrangement of the windings and gaps between windings. We analyzed the effects of the winding parameters, evaluated the cost of each design, and proposed a suitable HTS transformer model for future power distribution system.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.200-202
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• 2003

In this paper, 3-D electromagnetic analysis of a single phase 1MVA 22.9kV/6.6kV High Temperature Superconducting(HTS) transformer with double pancake windings by using the OPERA 3D was accomplished. And in order to perform the analysis of leakage impedances of a 1MVA HTS transformer, the energy conservation method was used. The efficiency voltage regulation and ％ impedance voltage drop of a 1MVA HTS transformer were obtained by the analysis of leakage impedances.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.12
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• pp.515-519
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• 2005

We have developed shell type 765kV transformers for generator step-up. Our research and development for shell type 765kV transformers have been continued since 1990. The shell type 765kV transformers of single phase 3MVA for step-up and 500MVA for power transmission were developed in Dec. 1992 and Oct. 1996, respectively. 204MVA 765kV transformer for generator step-up was also developed with the basis of technique and experience to the present. Total 12 phases of 204MVA 765kV transformers will be delivered at Tangjin thermal power plant by 2006. This paper describes electrical and structural features of the shell type 204MVA 765kV transformer.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.416-418
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• 2003

한국전력공사에서는 전압원 인버터형 FACTS 기기인 UFPC를 전남 강진군 강진변전소에 설치하였다. 강진 UPFC는 한전과 (주)효성이 공동으로 투자하고, 지멘스와의 기술제휴를 통해 개발하였으며, 40MVA 병럴인버터, 40MVA 직렬인버터로 구성되어 총 80MVA 용량이다. 강진 UPFC는 GTO를 이용한 3레벨 인버터 모듈 20MVA 총 4대로 구성되어 있으며, STATCOM, SSSC, UPFC의 3가지 운전모드를 갖는다. 현재 병렬인버터는 강진 모선전압 제어, 직렬인버터는 강진-장흥간의 조류제어에 기여하며, 상용운전 중이다. 본 논문에서는 강진 UPFC의 운전결과 및 효과를 분석하였다.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.160-161
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• 2012

(주)효성에서 자체 설계 및 개발한 FACTS(Flexible ACTransmission System) 기기중 하나인 1 MVA STATCOM(Static synchronous Compensator)은 전압 안정도 개선 및 역률제어를 통해 계통전력품질을 향상시킨다. 현재 개발된 1 MVA STATCOM은 제주 행원 풍력단지 내 풍력 발전기 14호기가 연계된 22.9 kV 계통에 병렬접속 되어있으며 현재 실증 운전 중에 있다. 본 논문에서는 1 MVA STATCOM의 설치 및 실증 운전사례를 소개한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.5
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• pp.391-395
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• 2008

KEPCO 80MVA UPFC has been operated in Gangjin Substation since May 2003. This UPFC is composed of 40MVA shunt inverter and 40MVA series inverter, and developed in technical cooperation between Hyosung and Siemens. KEPCO has tried to localize UPFC control technique after its installation and developed GTO Thyristor Valve Test Equipment for annual maintenance test. The development of this equipment make it possible to process GTO Thyristor module test automatically and manage historic data systematically, which could improve UPFC reliability.

• Geophysics and Geophysical Exploration
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• v.22 no.4
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• pp.225-238
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• 2019

Migration velocity analysis (MVA) for creating optimum depth-domain velocities in seismic imaging was applied to marine long-offset multi-channel data, and the effectiveness of the MVA approach was demonstrated by the combinations of conventional data processing procedures. The time-domain images generated by conventional time-processing scheme has been considered to be sufficient so far for the seismic stratigraphic interpretation. However, when the purpose of the seismic imaging moves to the hydrocarbon exploration, especially in the geologic modeling of the oil and gas play or lead area, drilling prognosis, in-place hydrocarbon volume estimation, the seismic images should be converted into depth domain or depth processing should be applied in the processing phase. CMP-based velocity analysis, which is mainly based on several approximations in the data domain, inherently contains errors and thus has high uncertainties. On the other hand, the MVA provides efficient and somewhat real-scale (in depth) images even if there are no logging data available. In this study, marine long-offset multi-channel seismic data were optimally processed in time domain to establish the most qualified dataset for the usage of the iterative MVA. Then, the depth-domain velocity profile was updated several times and the final velocity-in-depth was used for generating depth images (CRP gather and stack) and compared with the images obtained from the velocity-in-time. From the results, we were able to confirm the depth-domain results are more reasonable than the time-domain results. The spurious local minima, which can be occurred during the implementation of full waveform inversion, can be reduced when the result of MVA is used as an initial velocity model.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.626-633
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• 2005

This paper proposes a new 2MVA SSFG(Sag Swell Flicker Generator) injecting voltage by using series inverter. The proposed SSFG composes series inverter, DC capacitor as energy storage, rectifier and voltage clamp circuit. This SSFG is designed to generate typical power disturbances, such as voltage sag/swell, over/under voltage and voltage flicker. Also it is designed to generate unexpected voltage phase jumping waveform by controlling the series inverter. In this paper, three kinds of control methods for the proposed 2MVA SSFG we investigated by PSIM simulation. Also typical voltage sag, swell, flicker waveforms are implemented by adopting effective control method.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.162-165
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• 2001

본 논문은 EMTDC/PSCAD 프로그램을 이용한 80MVA UPFC(Unified Power Flow Controller)해석모델 개발과 2003년 실계통 적용시 적용효과에 대하여 기술하였다. UPFC는 90년대 이후 개발되고 있는 유연송전 시스템(FACTS : Flexible AC Transmission System)기기중 전압. 임피던스, 위상각등 송전선로에서의 전력조류제어를 위한 모든 파라미터를 동시에 고속으로 제어 할 수 있는 대표적인 FACTS 기기이며, 국내에도 2003년 강진 S/S에 80MVA 용량의 UPFC가 적용될 예정이다. 그러나 실 계통에서의 FACTS기기 적용을 위해서는 다양한 적용 효과분석 및 충분한 신뢰도 테스트가 선행되어야 한다. 따라서 이를 위한 기기 해석모델 개발은 매우 중요하다고 할 수 있다. 본 논문은 국내 전력 계통에 최초 적용되는 80MVA UPFC Pilot Plant에 대한 EMTDC/PSCAD 해석모델 개발결과에 대하여 기술하였다. EMTDC/PSCAD는 EMTP와 더불어 전력시스템의 과도현상 해석을 위한 신뢰성있는 프로그램이다.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.322-325
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• 2001

본 논문은 한전의 "FACTS 계통운용 기술개발연구(II단계:80MVA UPFC 도입, 설치)" 연구과제에서 수행된 연구내용 중 위치결정의 배경 및 기대효과에 대한 사항을 일부 발췌하여 논문으로 작성하였다. 위 연구과제는 한전 전력연구원과 (주)효성 중공업연구소, 전기연구소, 기초연, 미국의 Siemens사가 공동으로 참여하여 80MVA UPFC(Unified Power Flow Controller) 시스템, 변압기, 통신장치 등을 제작, 설치하여 2003년 4월에 완료되는 과제이다. 전력연구원은 80MVA UPFC가 효율적이고. 경제적인 운용이 가능하도록, 한전 본사 관련부서와 협의, 전남지역의 154kV 강진변전소를 설치위치로 최종 결정하였다.