• Journal of Electrical Engineering and Technology
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• 제5권3호
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• pp.400-406
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• 2010

This paper deals with parameter tuning of the Power System Stabilizer (PSS) for 612 MVA thermal power plants in the KEPCO system and its validation in a field test. In this paper, the selection of parameters, such as lead-lag time constants for phase compensation and system gain, is optimized using linear and eigenvalue analyses. This is then verified through the time-domain transient stability analysis. In the next step, the performance of PSS is finally verified by the generator's on-line field test. After the field test, measured and simulated data are also compared to prove the effectiveness of the models used in the simulations.

• 대한기계학회논문집A
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• 제35권1호
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• pp.47-52
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• 2011

이 논문은 내진검증을 수행하기 위한 유한요소 모델의 개발에 대하여 논의한다. 모델개발에 사용된 기기는 미국의 아칸사스 원자력 발전소의 전자기기 함으로써 유한요소해석 모델개발 과정을 보여준다. 증명된 모델은 진동수 50Hz 이하의 모든 주요모드에서 고유진동수가 5% 이내의 정확치를 가져온다. 유한요소모델은 질점질량과 강성도 방법을 사용한 COSMOSM 이라는 소프트웨어를 채용하여 수학적 모델의 eigenvalue 해석 및 동적해석이 수행되었다. 이 모델은 지정된 하중조건에서 AISC에서 규정한 허용응력치 이하를 나타내었다. 이모델에서 얻는 값들은 참고문헌에서 나타내는 내진 규정에 잘 부합하였다.

• 대한전기학회논문지:전력기술부문A
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• 제51권7호
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• pp.362-370
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• 2002

This paper describes the practical tuning method of dual-input PSS and its application to Muju P/P #2 with Proto PSS, which is based on DSP technology and uses both frequency and power. First, the model parameters of generator system used in this paper have been derived from the generator characteristic testing. Then, in the selection of PSS parameters, the Bode plot is plotted in order to tune the PSS's time constants which are able to compensate the phase lagging due to generator and excitation system. In addition, the eigenvalue analysis is also performed for determining a reliable PSS gain, $K_{s}$. Finally, the transient stability program has been utilized to verify the safe operation of Proto PSS against the predictable disturbances such as the AVR-step test and generator unloading test. In on-site test, the simulated results have been identically duplicated by implementing AVR step test in Muju P/P #2 with Proto PSS, which has the previously designed PSS parameters.s.

• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.2027-2032
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• 2005

This paper demonstrates details of thermal behavior of Langmuir-Blodgett (LB) film of poly(tert-butyl methacrylate) (PtBMA) by using the principal component analysis based two-dimensional correlation spectroscopy (PCA2D) through eigenvalue manipulating transformation (EMT). By uniformly lowering the power of a set of eigenvalues associated with the original data, the smaller eigenvalues becomes more prominent and the subtle contribution from minor components is now highlighted much more strongly than the original data. Thus, the subtle difference of thermal behavior of LB film of PtBMA from minor components, which is not readily detectable in the conventional 2D correlation analysis, is much more noticeable than the original data. PCA2D correlation spectra with EMT operation for the temperature-dependent IR spectra of LB film of PtBMA reveal the hidden property of phase transition processes during heating.

• Structural Engineering and Mechanics
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• 제45권1호
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• pp.69-93
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• 2013

The present study deals with the dynamics of the flapwise (out-of-plane) vibrations of a rotating, internally damped (Kelvin-Voigt model) tapered Bernoulli-Euler beam carrying a heavy tip mass. The centroid of the tip mass is offset from the free end of the beam and is located along its extended axis. The equation of motion and the corresponding boundary conditions are derived via the Hamilton's Principle, leading to a differential eigenvalue problem. Afterwards, this eigenvalue problem is solved by using Frobenius Method of solution in power series. The resulting characteristic equation is then solved numerically. The numerical results are tabulated for a variety of nondimensional rotational speed, tip mass, tip mass offset, mass moment of inertia, internal damping parameter, hub radius and taper ratio. These are compared with the results of a conventional finite element modeling as well, and excellent agreement is obtained.

• 대한전기학회논문지:전력기술부문A
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• 제55권1호
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• pp.13-17
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• 2006

In this paper, the RCF(Resistive Companion Form) analysis method which is used to analyze small signal stability problems of non-continuous systems including switching devices. The RCF analysis method is mathematically rigorous and computes eigenvalue of the system periodic transition matrix based on discrete system analysis method. As an effect of switching operations, the eigenvalues of the systems are changed and newly unstable oscillation modes may be occurred. As an illustrating example, the oscillation modes of the system with different switching time intervals are computed exactly by the RCF analysis method and the results show that ON/OFF time intervals of switching equipments are important factors to make the system stable or unstable. This result shows that the RCF analysis method is very powerful to analyze small signal stability problems of power systems including switching devices such as FACTS equipments.

• Structural Engineering and Mechanics
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• 제3권4호
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• pp.313-324
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• 1995

Flexible cantilever pipes conveying fluids with high velocity are analysed for their dynamic response and stability behaviour. The Young's modulus and mass per unit length of the pipe material have a stochastic distribution. The stochastic fields, that model the fluctuations of Young's modulus and mass density are characterized through their respective means, variances and autocorrelation functions or their equivalent power spectral density functions. The stochastic non self-adjoint partial differential equation is solved for the moments of characteristic values, by treating the point fluctuations to be stochastic perturbations. The second-order statistics of vibration frequencies and mode shapes are obtained. The critical flow velocity is first evaluated using the averaged eigenvalue equation. Through the eigenvalue equation, the statistics of vibration frequencies are transformed to yield critical flow velocity statistics. Expressions for the bounds of eigenvalues are obtained, which in turn yield the corresponding bounds for critical flow velocities.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.112-115
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• 2001

Eigenvalue perturbation theory of augmented system matrix(AMEP) is a useful tool in the analysis and design of large scale power systems. This paper describes the application results of AMEP algorithm with respect to all controller parameter of KEPCO systems. AMEP for interarea and local mode can be used for turning controller parameter, and verifying system data and linear model of controller.

• 정보처리학회논문지A
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• 제11A권1호
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• pp.67-74
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• 2004

대부분의 병렬 알고리즘은 동기 알고리즘으로, 올바른 계산을 위해 작업을 일찍 끝낸 빠른 프로세서들은 동기점에서 느린 프로세서를 기다려야 하는데, 프로세서들의 성능이 다를 경우 연산 속도는 가장 느린 프로세서에 의해 결정된다. 본 논문에서는 거대 고유치 문제의 주요 고유쌍을 구하는 문제에 있어서 빠른 프로세서의 유휴 시간을 줄여 수렴 속도를 가속한 수 있는 동기/비동기 혼합 알고리즘을 고안하고 이를 MPMD 프로그래밍 방식을 사용하여 구현하였다.

• 대한전기학회논문지
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• 제34권6호
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• pp.213-219
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• 1985

Superconducting Magnetic Energy Storage (SMES) system can be used for power system stabilization by absorbing or discharging active and reactive power through thyristor-comtrolled converters. In this paper, we have proposed a control algorithm that the active and reactive powers of SMES are simultaneously controlled to increase power system dynamic stability. The proposed method was applied to one machine-infinite and three machines and three load model systems. And it has been shown that the proposed algorithm is more effective in power system stabilization than the conventional one that only the active power of SMES is controlled. Eigenvalue sensitivity analysis method is introduced to estimate the optimal location of SMES in the sense of the power system oscillation mode.