• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.296-298
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• 2009

Ac-dc 싸이리스터 컨버터에서 전류기준값의 부호가 변화할 경우에 적분항 초기값을 통해 전류제어 과도특성을 개선하는 연구가 있었다. 이 논문에서는 전류기준값의 기울기에 변화가 있을 때 그 변화를 일으키기 위한 전압을 계산하고 그 값을 점호각 $\alpha$로 환산하여 시스템에 적용시켜 변곡점 부근에서의 전류제어 특성을 개선하는 방법을 제시하였다. 또한 전류기준값에 노이즈가 포함된 경우 LPF 유/무에 따른 특성변화와 노이즈가 포함되지 않은 경우 LPF 유/무에 따른 특성변화를 관찰하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2209_2210
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• 2009

송전계통에서 가장 많이 발생하는 고장은 일시고장이며, 이 중 70%~80%가 아크지락 고장이다. 일시 고장시 계통의 빠른 복구를 위한 성공적인 재폐로를 이루기 위해서는 2차아크의 재점호와 소멸시간이 중요한 변수로 작용한다. 따라서 이러한 2차아크의 특성을 분석하고 적절한 소호시점을 알아내는 것이 성공적으로 고장 후 계통을 복구시키기 위해 필요하다. 본 논문에서는 전력 계통의 과도현상 분석 프로그램인 EMTP(Electro Magnetic Transient Program)를 이용하여 765kV 송전계통에서 아크 지락 고장을 시뮬레이션 하고, 송전선로내 고장지점을 다양하게 변화시켜 가며 아크 전압 특성을 분석하였다.

• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.208-209
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• 2006

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.213-215
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• 2006

A static frequency converter(SFC) in a pumped storage power plant is important equipment for converting electric motor kinetic energy into electric Bower. A SFC monitoring system consists of high voltage thyristor firing equipment, fault detection module, data gathering module, real time data processing equipment and man machine Interface system. This paper describes SFC system overview, developed SFC monitoring system configuration including system characteristics. and successful application result to San-Cheong pumped storage power plant.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.120-124
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• 1995

TCSC can not only increase power flow but also damp low frequency oscillation by controlling firing angles of thyristors. But, a model considering voltage, current firing angles is not derived. This paper used a small signal model considirng these variables which was derived in paper [1]. TCSC model is combined with swing equation. Being related to rotor angles and firing angles of thyristors, current and synchronizing torque coefficient is reformulated. Because firing angles of thyristors can be controlled only twice within one period, swing equation is transformed to discrete time model. It is shown that low frequency oscillation can be damped by controlling firing angles in one machine infinite bus power system.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.329-330
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• 2008

제주-해남간 HVDC 변환설비는 제주 전력수요의 약 40%를 담당하는 주요 설비로, 국내에서는 처음으로 도입되어 상용 운전중인 직류송전 설비이다. 10년간의 변환설비 운전중에 크고 작은 고장이 많이 발생하였으며 PCB Card에 의한 고장은 전체 고장의 약 30%를 차지하고 있다. 본 논문에서는 해남변환소에서 사용중인 VBE (Valve Base Electronics : Thyristor 점호 제어반) Cubicle에 설치된 Databack PCB Card 점검장비 개발내용을 설명하였다. 이 장비 사용시 설비사고 및 고장의 원인을 줄일 수 있고, 카드의 연도별 이력관리를 할 수 있다. 또한 Card의 경년열화 특성을 파악하여 교체시기를 판단할 수 있고 Card 시험시간의 단축이 가능하다. 상기 이외에 점검기술에 대하여 기존 방식과 비교하고 시험기 개발 및 운영사항에 대하여 기술하고자 한다.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.481-484
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• 2006

A electric power conversion system in a pumped storage power plant is important equipment for converting electric motor kinetic energy into electric power. A electric power conversion monitoring system consists of high voltage thyristor firing equipment, fault detection module, data gathering module, real time data processing equipment and man machine interface system. This paper describes electric power conversion system overview, the developed SFC monitoring system configuration including system characteristics, and successful application result to San-Cheong pumped storage power plant.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.565-568
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• 2003

The conventional analog-based firing circuit can be implemented by comparing a linearly decreasing periodic sawtooth waveform synchronized to the ac line, with a voltage corresponding to the desired converter delay angle. This circuit requires a large number of components (resistance and capacitor) and careful adjustment of the synchronization circuity In this paper a novel firing circuit is proposed for thyristor switch is elements. The proposed circuit is implemented on the basis of the analog cosine method using FPGA and microprocessor.

• Journal of the Korean Society of Tobacco Science
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• v.6 no.2
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• pp.179-184
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• 1984

This experiment was carried out to select the suitable burley varieties for paddy field. Two varieties, two $F_1$ hybrids and three $F_1$ hybrids with pale yellow line which were all early maturing were tested in the paddy field condition. The results were as follows. 1. Va 528 and all $F_1$ hybrids flowered 4-8 days earlier than Burley 21. 2. Leaf maturity among varieties and $F_1$ hybrids were not significantly different at first priming, but significant differences were detected from second to forth primings. (MS Ky 12x JB 7802-30)Fl and (MS Br 21 x L8)$F_1$ hybrids matured 3-5 days earlier than Burley 21. Pale yellow hyorids matured early, yielded high and were favorable in physical properties, but were low in quality. 4. Va 528 and (MS Br 21 x L8) $F_1$ hybrid showed earthy maturing, high yield and good quality compared with Burley 21. So two varieties were considered suitable for paddy field cultivation.

• Journal of the Korean Society of Tobacco Science
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• v.3 no.2
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• pp.115-122
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• 1981

Data for this study were obtained from Burley 21 (Nicotiana tabacum L.) grown under various densities on the field in 1978 and 1979 at the Jeonju Experiment Station, Korea Ginseng & Tobacco Research Institute. Interrelations between yield and its components were statistically studied by correlation, regression, and pathway analysis. Correlation of yield with plant population was significant and positive. Quadratic functions for yield vs. plant population and the length of the largest leaf were fitted to the data. Multiple recession equation between yield and its components (leaf number ($X_1$), a leaf area ($X_5$), weight per unit leaf area ($X_9$), plant population ($X_14$)), was significant at the 5% level. Measuring the relative importance of its components on yield, plant population was 49.5%, weight per unit leaf area 25.3%, a leaf 15.6%, and leaf number 9.8%.