• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.381.2-381
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• 2002

많은 동적해석 설계자들이 재료물성치의 불확실성, 연결강성 그리고 경계조건등의 해석상에서 나타날 수 있는 불확실성 때문에 모달 테스트에 많은 관심을 가지고 있었으며 또한 수행해 왔다. 그러나 대형구조물의 경우 저주파수 대역에서의 가진력 크기, 가진력 계측 문제등으로 동특성 실험을 위한 모달 테스트를 수행하기가 쉽지 않은 실정이다. (중략)

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.77-78
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• 2015

For the smooth operation and efficient management of pumped storage power plants, we should be understand a generator, turbine, exciter, governor, and stabilizer and prepare an abnormal accident through an accident simulation by software such as PSCAD, PSS/E. This paper investigates configuration of the generator system of ${\bigcirc}{\bigcirc}$ pumped storage power plant. And describes the modeling and fault simulation studies using PSCAD.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1156-1158
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• 1997

This paper presents the proposed full-order observer-based sliding mode power system stabilizer(FOOSMPSS) for finding unmeasurable state variables(torque angle, quadratic-axis transient voltage, exciter output voltage, voltage regulator output voltage and output voltage) by measuring angular velocity. The simulation results is shown by the comparison of the FOOPSS with the proposed FOOSMPSS.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1731-1732
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• 2005

본 논문은 풍력발전기 안정된 출력발전을 위하여 풍력 동기발전기 여자기 설계에 중점을 두었다. 풍력발전기 최대 발전을 얻기 위해 동기발전기 속도제어와 여자제어가 필요하다. 속도제어에서 AC/DC 정류기는 전력 다이오드로 구성하고 DC/AC 인버터는 IGBT로 구성하였다. 여자제어 구성은 AC/DC는 전력 다이오드로 구성하고 DC단은 DC/DC 부스트로 구성하였다. 또한, 동기발전기 여자 제어기 제어신호에 동기발전기 출력 AC/DC의 전력과 동기발전기 속도로 적절하게 조절함으로서 안정되고 최대 출력이 되도록 하였다. 또한, 제안된 제어기가 우수한 성능을 보임을 시뮬레이션으로 증명하였다.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.256-258
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• 1998

This paper presents a control system design for the UPFC of FACTS devices by optimal control scheme to enhance small-signal stability in the Power system. The feature of this UPFC controller is coordinated with generator exciter controller(AVR, PSS) to improve the total Power system stability and performance.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.5
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• pp.398-408
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• 2007

For better evaluation of material thickness by using the reflection type pulsed eddy current method, various probe models are designed and their response signals, characteristics, and sensitivities to thickness variation are investigated by a numerical analysis method. Since the sensor needs to detect magnetic fields from eddy currents induced in a test material, not from the exciter coil, two types of models that are shielded by the combination of copper and ferrite and only by ferrite are considered. By studying response signals from these shielded probe models, the peak value and the zero crossing time are selected as useful signal features for the evaluation of material thickness. Investigation of sensitivities of these two features shows that the sensitivity of peak value is more useful than that of zero crossing time and that the probe shielded only by ferrite gives much better sensitivity to thickness variation.

• Journal of Energy Engineering
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• v.5 no.1
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• pp.72-79
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• 1996

The effect of controllers-Exciter, Power System Stabilizer, and Static Var Compensator-in one machine infinite bus system is investigated in this paper. The structure of generator state matrix with controllers is represented, while the Static Var Compensator is installed in generator terminal bus. Eigen-value analysis is performed and the effects of controllers to the dominant eigenvalue in one machine infinite bus system are represented by first order eigenvalue sensitivity coefficients while the operating conditions of the system are varied. Optimization of controller parameters using first order eigenvalue sensitivity coefficients is performed by the Simplex Method. It is proved that exciter control is the most efficient method to improve stability of the system and the effect of Static Var Compensator is small, in the case of one machine infinite bus system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.9
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• pp.315-324
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• 1983

Dynamic stability problems have been experienced with a generator connected to an infinite bus through a long transmission line. Nuclear turbine-generator units #1 and #2 at the Winsconsin Electric Power Point Baech Station were found to be dynamically unstable when one unit is isolated on one of the lines to Milwaukee or when two units are isolaed on the lines to milwaukee. Power System Stabilizers(PSS) were applied to the excitation system to provide stable operation under these conditions. Suitable settings for the PSS were predetetermined analytically by computer method and root licus analysis of an equivalent single machine-infinite bus configuration. This procedure allows graphical approach to the design of power stabilizers and serves as assynthesis procedure when the design constraints are relaxed so the the speed stabilizer is required ro provide animprovement in system damping. A simplified model of the complete exciter generator system is shown to be adequate for this type of analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.624-631
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• 2011

In this paper, the RCF method is used in sensitivity analysis problems of the discrete power systems including both series FACTS equipments such as TCSC in transmission lines and generator controllers such as Exciter and PSS in generator terminal. To apply the RCF method in small signal stability problems of discrete power systems, state transition equations of controllers and TCSC are derived and the sensitivity calculation algorithm using state transition equations in discrete time domain is devised. The results of eigenvalue analysis showed that the variations of eigenvalues after periodic switching operations of TCSC can be calculated exactly by the RCF method and the change of firing angles in TCSC have important effect to determine the stability of power systems.

• Journal of the Korean Magnetics Society
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• v.21 no.2
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• pp.61-66
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• 2011

The miniaturization of electrostatic precipitator is becoming a key element to the success of the efficient electrostatic precipitator due to the limited space allowed to install electrostatic precipitator in subway tunnel. Nowadays, a research on electrostatic precipitator in urban railroad equipment technology is under an active study. Finite element method has been used one of the most popular techniques, but it consumes a lot of time especially in computation iterations. Accordingly, the lumped parameter analysis can be an alternative tool to FEM because of its computation iteration capability with fair accuracy. In this paper, lumped parameter model and the simulation results are presented. In addition, the result of lumped parameter analysis is compared with those obtained from finite element analysis for verification.