• International Journal of Fluid Machinery and Systems
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• v.4 no.2
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• pp.289-306
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• 2011

In the development of very high head pumped storage projects, one of the critical problems is the strength of pumpturbine runners. Data obtained by stress measurements of high head pump-turbine runners indicated that dynamic stress due to the vibration of runner might be detrimental, possibly to cause fatigue failure, if the runner were designed without proper consideration on its dynamic behaviour. Numerous field stress measurements of runners and model tests conducted with hydrodynamic similarity revealed that the hydraulic excitation force developed by the interference of rotating runner blades with guide vane wakes sometimes would induce such heavy vibration of runner. Theoretical and experimental investigations on both the hydraulic excitation force and the natural frequencies of runner have been conducted to explore this forced vibration problem.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.293-324
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• 1996

Compact solid-state blue laser have great potential for use in optical data storage, laser beam printing, particle countering, reprographics, holography, and fluorescent bioanalysis. We report recent progresses in qualities of LiB3O5 and K3Li2(TaxNb1-x)5O15 nonlinear crystals which are essential in manufacturing bulk-type blue SHG devices. We also review newly developed violet-blue laser, 20 mW output, using intracavity frequency doubling of a diode laser pumped Cr:LiSrAlF6 laser with low loss LiB3O5 crystal as a frequency doubler.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2062-2064
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• 2008

○○양수 발전소에서 운전되고 있는 SFC에서 양수모드 운전시 간헐적으로(1회/1-3개월) 승속실패(승속실패 시점은 대략 정격속도(300RPM)의 10%인 30RPM 전,후) 사례가 발생하나 SFC 제어 창에는 Alarm이나 Trip 관련 경보가 전혀 발생되지 않는 등 비정상 운전임에도 불구하고 원인을 파악할 수 있는 관련 정보를 취득할 수 없는 상황에서 SFC를 포함하여, 관련되어 운전되는 AVR, 인터페이스 판넬 등에 대하여 정밀점검을 시행하고, 원인을 규명함과 동시에 정상화 시킨 진단 사례임.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.278-282
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• 1997

This paper describes results of modal testing for a high head pump-turbine runner of the Muju pumped storage power plant. The head of the pump-turbine is 601 m and the outside diameter of its runner is 4,410 mm. The modal testing was done for two conditions : 1) the runner in air ; 2) the runner in water. For both conditions, obtained are natural frequencies, corresponding mode shapes and damping ratios. From the testing, it is found that the natural frequencies of the pump-turbine runner in water is reduced approximately 40 % due to additional mass effect of the water.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.870-873
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• 1988

AESOPS computer program is designed to find those eigenvalues of a linear dynamic system model which most strongly characterize oscillations between generator rotors. The low frequency oscillation actually occurred in October, 1986 in Korean Electric Power Corporation (KEPCO) System. 28 oscillation modes are identified through computer runs and two of them are calculated unstable in the case of the start of a pumped-storage unit. This program is considered to complement the conventional PSS/E stability program for the stability study of KEPCO system.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.954-955
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• 2006

SFC(Static Frequence Converter)system has come to be used as start-up drive system for large synchronous machine in many industry applications. Many papers have been presented the control algorithm for pumped storage power generation using SFC system but they did not included about the detailed start-up algorithm of gas turbine using SFC system. This paper presents the important field weakening control algorithm of a large synchronous machine using SFC system and the results of experiment show that the proposed algorithm is proper and effective about this.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.166-169
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• 2005

대용량 동기 발전 전동기 운전의 기동용 시스템으로 주로 사이리스터를 이용한 정지형 주파수 변환(SFC : Static Frequency Converter) 시스템이 사용되고 있다. 본 논문에서는 SFC시스템의 기동부터 회생까지 파형을 5KVA급 동기 전용 발전기 모의실험을 통하여 제시하고 330MVA급 양수 발전소의 실측 파형을 분석하여 알고리즘을 도출하였으며 또한 시뮬레이터 파형과 실제 파형을 비교해 함으로써 양수발전소의 제어 시스템의 운전특성을 유추 및 분석하였다.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.350-351
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• 2018

본 논문은 가변속 양수발전 시스템의 모델링 및 양수발전용 전력변환장치 제어 구조를 분석하고 모델링하였다. 기존 양수발전 시스템은 동기 발전기를 사용하였지만 신재생 에너지원의 출력 변동 및 부하 변동에 따른 주파수의 변화에 빠른 대응을 위한 가변속 양수발전 시스템을 채용하여 계통 전력과 전압, 주파수 등을 보상한다. 양수 발전소의 터빈, 게이트, 조속기 등을 분석하여 모델링하였으며, Doubly fed induction generator를 위한 back-to-back 전력 변환 장치를 발전 및 양수 모드에 사용하기 위해 벡터제어, 속도제어, 유효-무효 전력 제어기 등을 모델링 하였다.

• Solar Energy
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• v.18 no.4
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• pp.101-110
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• 1998

The purpose of this research is to study the charateristics and manufacture of a composite heat pipe system with rotational and static pipe. A composite heat pipe system were tested to obtain the relationship between the expansion injector and auxiliary expansion for the motion of the working fluid by the experimental results. In addition the heat transport characteristics were found based on wall temperature of rotor, expansion injector, storage tank and vapor temperature. Water is used as working fluid of heat pipes. As the results of experiments, the composite heat pipe was operated for long times, 10 hour above with various rotational speed in performance. There were a few unexpected data by the capillary pumped loop at small working fluid, but as a whole the testing was successful.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.2
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• pp.73-79
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• 1987

This paper describes a new algorithm to evaluate the production cost for a generation system including energy-limited hydroelectric plants. The algorithm is based upon the analytical production costing model developed under the assumption of Gaussian probabilistic distribution of random load fluctuations and plant outages. Hydro operation and pumped storage operation have been dealt with in the previous papers using the concept of peak-shaving operation. In this paper, the hydro problem is solved by using a new version of the gradient projection method that treats the upper / lower bounds of variables saparately and uses a specified initial active constraint set. Accuracy and validity of the algorithm are demonstrated by comparing the result with that of the peak-shaving model.