• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.116-118
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• 2003

This paper describes the contingency analysis methods which are used in the transmission reliability program, TPLAN. Reliability criterion, reliability assessment, ranking methods, and screening methods are discussed. In addition, a simple 25-bus system was tested with TPLAN and its analyses are presented in this paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.285-288
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• 2000

This paper presents a technique for contingency ranting using line capacity calculation method and outage distribution factors(LODF) which are established by generation shift distribution factors from DC load flow solutions. By using the LODF, the line flow can be calculated a ccording to the modification of base load flow if the contingency occur. To obtain contingency ranting, maximum power tansferred to the load is obtained when load impedance $Z_r$ equal to line impedance $Z_s$. ( $Z_r$/ $Z_s$=1) The proposed algorithm has been validated in tests on a 6-bus test system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1042-1045
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• 1999

This paper presents a new method for contingency selection of the transient stability. Contingency ranking in transient stability is done by estimating the change in the imaginary part of electro-mechanical oscillation mode, which represents modal synchronizing coefficient. And the change in the imaginary part is obtained by applying eigen-sensitivity theory of augmented matrix to linear system model. The Proposed algorithm was tested for New England System and compared the results with PSS/E dynamic simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전력기술부문
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• pp.199-201
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• 2007

This paper presents new contingency screen and ranking method using the time-domain simulation program and energy function. Since the suggested method is very simple and has fast computation time to calculate energy margin and list the contingency according to the its severity, it can be used in connection with the on-line TSA which has accurate binary search algorithm in parallel or distributed computing environment. The suggested method has been tested by appling to 3-machine and 9-bus system, and its effectiveness has been verified.

• 대한전기학회논문지
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• 제32권10호
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• pp.360-366
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• 1983

In this paper, operation cost of the system is calculated by the probabilistic simulation method. And it is proved that only 20 iterative simulations are enough to get the result obtain by the Monte Carlo simulation method which requires more than 1000 iterative simulations. In the probabilistic simulation method we use the ranking of line contingency which is derived from the line countingency selection algorithm proposed in (2). In using this method the nature of the sparsity of the power system is used.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.239-242
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• 2001

This paper presents a windows program package for solving security constrained OPF in interconnected power systems, which is based on the combined application of evolutionary programming(EP) and sequential quadratic programming(SQP). The objective functions are the minimization of generation fuel costs and system power losses. The control variables are the active power of the generating units, the voltage magnitude of the generator, transformer tap settings and SVC setting. The state variables are the bus voltage magnitude, the reactive power of the generating unit, line flows and the tie line flow. In OPF considering security, the outages are selected by contingency ranking method. The resulting optimal operating point has to be feasible after outages such as any single line outage(respect of voltage magnitude, reactive power generation and power flow limits). The OPF package proposed is applied to 10 machines 39 buses model system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.194-196
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• 2001

This paper presents a hybrid algorithm for solving security constrained OPF in interconnected power systems, which is based on the combined application of evolutionary programming (EP) and sequential quadratic programming (SQP). The objective functions are the minimization of generation fuel costs and system power losses. In OPF considering security, the outages are selected by contingency ranking method. The control variables are the active power of the generating units, the voltage magnitude of the generator, transformer tap settings and SVC setting. The state variables are the bus voltage magnitude, the reactive power of the generating unit, line flows and the tie line flow. The method proposed is applied to the modified IEEE 14buses model system.

• Communications for Statistical Applications and Methods
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• 제6권3호
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• pp.947-956
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• 1999

We define a crossing point $x_0$ such that f(x)$\geq$g(x) for x$\leq$$x_0$ and f(x)$\leq$g(x) for x>$x_0$ where f and g are probability density functions. We may encounter suchy situation when we compare two histograms from two independent observations. For example two contingency tables where initially admitted students and actually enrolled students are classified according to their high school ranking may show such situation, In this paper we consider maximum likelihood estimation of cell probabilities when a crossing point exists, We first assume a known crossing point and find an estimator. The estimation procedure for the case of unknown crossing point is just a straightforward extension. A real data is analyzed for an illustrative purpose.

• 대한전기학회논문지:전력기술부문A
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• 제50권12호
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• pp.584-590
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• 2001

This paper presents a windows program package for solving security constrained OPF in interconnected Power systems, which is based on the combined application of evolutionary programming(EP) and sequential quadratic programming(SQP). The objective functions are the minimization of generation fuel costs and system power losses. The control variables are the active power of the generating units, the voltage magnitude of the generator, transformer tap settings and SYC setting. The state variables are the bus voltage magnitude, the reactive power of the generating unit, line flows and the tie line flow In OPF considering security, the outages are selected by contingency ranking method. The resulting optimal operating point has to be feasible after outages such as any single line outage(respect of voltage magnitude, reactive power generation and power flow limits). The OPF package proposed is applied to IEEE 14 buses and 10 machines 39 buses model system.