• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.685-688
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• 1998

In this research project, two aspects of small signal stability are studied: improvement in Hessenberg method to compute the dominant electromechanical oscillation modes and siting FACTS devices to damp the low frequency oscillation. Fourier transform of transient stability simulation results identifies the frequencies of the dominant oscillation modes accurately. Inverse transformation of the state matrix with complex shift equal to the angular speed determined by Fourier transform enhances the ability of Hessenberg method to compute the dominant modes with good selectivity and small size of Hessenberg matrix. Any specified convergence tolerance is achieved using the iterative scheme of Hessenberg method. Siting FACTS devices such as SVC, STACOM, TCSC, TCPR and UPFC has been studied using the eigen-sensitivity theory of augmented matrix. Application results of the improved Hessenberg method and eigen-sensitivity to New England 10-machine 39-bus and KEPCO systems are presented.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.749-753
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• 1996

This paper presents a new method for first and second order eigen-sensitivity analysis of system matrix in augmented form. Eigen-sensitivity analysis provides invaluable informations in power system planning and operation. However, conventional eigen-sensitivity analysis methods, which need all the eigenvalues and eigenvectors, can not be applicable to large scale power systems due to large computer memory and computing time required. In the proposed method, all sensitivity computations for a mode are carried out using the augmented system matrix and its own eigenvalue and right & left eigenvectors. In other words sensitivity analysis for a mode does not need informations on the other eigenvalues and eigenvectors and sparsity technique can be fully utilized. Thus compuations can be done very efficiently with moderate computer memory and computing time even for large power systems. The proposed algorithm is tested for one machine infinite bus system.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.365-368
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• 1998

In this research project two aspects of small signal stability are studied: improvement in Hessenberg method to compute the dominant electromechanical oscillation modes and siting FACTS devices to damp the low frequency oscillation. Fourier transform of transient stability simulation results identifies the frequencies of the dominant oscillation modes accurately. Inverse transformation of the state matrix with complex shift equal to the angular speed determined by Fourier transform enhances the ability of Hessenberg method to compute the dominant modes with good selectivity and small size of Hessenberg matrix. Any specified convergence tolerance is achieved using the iterative scheme of Hessenberg method. Siting FACTS devices such as SVC, STACOM, TCSC, TCPR and UPFC has been studied using the eigen-sensitivity theory of augmented matrix. Application results of the improved Hessenberg method and eigen-sensitivity to New England 10-machine 39-bus and KEPCO systems are presented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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• pp.507-512
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• 2017

Recently, more electric power facilities have been miniaturized and it is noted that the facilities maintenance will be essential through operation optimization. In this paper we applied and examined the operation optimization of electric power facilities by applying Matrix system which can improve reliability to minimize outage and recover failure rapidly when blackouts happen at 25.8kV Gas Insulated Switchgear(GIS). The fundamental problem for facilities maintenance of GIS can happen due to indeterminable internal state in real time. Matrix optimization organizes action states in all containers which contain pressurized $SF_6$ Gas such as circuit breaker, disconnector switch, bus for utilizing them each area. Then, we connect it with power system to monitor and control internal state remotely in real time, and we can minimize blackout zone or outage. Considering above process, we improved stability of overall facilities.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.6
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• pp.390-395
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• 1987

There is a variety not only of research topics but also of research techniques in electric power problems. It is well known that a significant increase in the rate of convergence can be obtained for the Gauss-Seidel method using the bus admittance matrix by applying acceleration factors determined empirically. The acceleration factor is calculated theoretically by using the bus voltage sensitivity (buses voltage interact each other) in this paper. It is observed that the proposed method using calculated acceleration factor gives better results than those of the method using calculated acceleration factor gives better results than those of the method using empirical one.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.66-68
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• 2000

The Eigen analysis in large power system provides much useful information that is not got in nose curve. The branch participation factor is not quantitative information and is an indirect method calculating incremental change in branch reactive loss. But the Eigen sensitivity analysis to each mode is direct and provides of quantitative information but this method because of needing much time is used in large power system. In this paper the Hessenberg method is used to obtaining dominant eignvalues and corresponding eigenvectors of Jacobian matrix. Ranking the critical contingencies is done by computing the Eigen sensitivity of each dominant eignvalues for changes of each line. The proposed algorithm is tested on the New England 30-bus system and KEPCO system in the year of 2000, which comprises of 791-bus and 2500-branches.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.173-178
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• 1989

Optimal Power Flow (OPF) solution by the Newton's method provides a reliable and robust method to classical OPF problems. The major challenge in algorithm development is to identify the binding inequalities efficiently. This paper propose a simple strategy to identify the binding set. From the mechanism of penalty shifting with soft penalty in trial iteration, a active binding sit is identified automatically. This paper also suggests a technique to solve the linear system whore coefficients are presented by the matrix. This implementation is highly efficient for sparsity programming. Case study for 3,5,14,118,190 bus and practrical KEPCO 305 bus system are performed as well.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.11
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• pp.542-548
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• 2000

In this paper, we proposed a new load flow analysis algorithm. In order to develop it, we converted typical power flow problem into optimal problem. This problem has the objective function that minimize the difference between calculated values and specified values of bus powers and subject to bus power equations of P and Q. Using it, we solved the divergence by singularity of Jacobian matrix, the divergence by initial value in the typical power flow study. In the study of a sample system, we verified the superiority of proposed algorithm.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.6
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• pp.232-240
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• 1984

This paper presents a new algorithm for power system contingency analysis and sensitivity matrix associated with the contingency measures. The algorithm has several advantages over conventional ones in terms of both accuracy and time of computation by improving base A.C. load flow calculation scheme, contingency evaluaiton formula based on a variable slack generating power concept and transmission loss formula. The algorithm was tested for the 5-bus system and 24-bus IEEE Reliability Test system with satisfactory results.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.3
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• pp.223-231
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• 1990

Optimal Power Flow (OPF) solution by the Newton's method provides a reliable and robust method to classical OPF problems. The major challenge in algorithm development is to identify the binding inequalities efficiently. This paper proposes a simple strategy to identify the binding set. From the mechanism of penalty shifting with soft penalty in trial iteration, an active binding set is identidied automatically. This paper also suggests a technique to solve the linear system whose coefficients are presented in the matrix from. This implementation is highly efficient for sparsity programming. Case studies for 3, 5, 14, 118 bus and practical TPC-190, KEPCO-306 bus systems are performed as well.