• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.3
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• pp.165-172
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• 2003

This paper presents an operation scheme to enhance the power system security by applying FACTS on Power systems. Three main generic types of FACTS devices are suggested an illustrated. Flow congestions over lines have been solved by controlling active power of series-compensated FACTS devices and low voltages at buses have been solved by controlling reactive power of shunt-compensated FACTS devices. Especially, Especially, UPFC has been applied in both line congestion and low voltages. Two kinds of indices which indicate the power system security level related to line flow and bus voltage are utilized in this paper. They have been minimized to enhance the power system security level through the iterative method and the sensitivity vector of security index is derived to determine the direction to minimum. The proposed algorithm has been tested on the IEEE 57-bus system with FACTS devices in a normal condition and a line-faulted contingency.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.886-890
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• 1997

This paper presents shows various process of dynamic voltage collapses which were initiated by power system disturbances, and the impacts of dynamic voltage controllers. According to the analysis results, the composition of induction motors with short time constant strongly affect the voltage collapse. To escape the voltage collapse, adding fast acting reactive compensation device, such as SVC, at high reactive loss sensitivity(${\partia}Qloss/{\partia}PL$) point could be one of a good countermeasure.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.381-383
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• 2002

This paper proposes a MATLAB program for solving security-constrained optimal power flow using linear programming. Security-constrained optimal power flow can find an optimal generation satisfying bus voltage limits, line flow limits, reactive generation limits, even if contingency occurs. Sensitivity matrixes are obtained based on power flow solutions with and without single line contingency. This program is tested for an IEEE 14bus system with 5 generators Results shows good ability of finding optimal solution in case of a single line contingency.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.944-949
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• 2012

As modern power systems become large and complicated, the automated voltage and reactive power control system is required in most developed countries due to the recent amazing progress of computer net works and information thechnology. So far the voltage control has been depend on human operator in korean power system. This paper presents an intelligent voltage control system based on sensitivity analysis and artificial intelligence technology. Detailed state space modeling technique is discussed and a new performance index is proposed to speed up the searching performance of the expert system. As the searching strategy is very important factor of the speed of expert system the least first search algorithm is applied using this performance index. The intelligent voltage control system is applied to the Jeju power system. As a result, case studies showed a promissing application of the intelligent voltage control system.

• 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.

• Journal of Energy Engineering
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• v.12 no.1
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• pp.42-48
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• 2003

In system planing and operation, voltage and reactive power control is very important. The voltage deviation and system losses can be reduced through control of reactive power sources. In general, there are several different reactive power sources, we used switched shunt capacitor to improve the voltage profile and to reduce system losses. Since there are many switched shunt capacitors in power system, so it if necessary to coordinate these switched shunt capacitors. In this study, Genetic Algorithm (GA) is used to find optimal coordination of switched shunt capacitors in a local area of power system. In case study, the effectiveness of the proposed method is demonstrated in KEPCO's power system. The simulation is performed by PSS/E and the results of simulation are compared with sensitivity method.

• Journal of the Korean Institute of Gas
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• v.25 no.1
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• pp.40-47
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• 2021

In this study, hazards of decomposition and explosion for tert-butylperoxymaleate(TBPM), an organic peroxide, were evaluated by using various equipment to determine the cause of a fire explosion accident. As a result of DSC analysis, the instantaneous power density of TBPM was 26,401 kW/ml, and the NFPA reactive index(Nr) was classified as 4. And the positive value of EP(explosive propagation) and SS(shock sensitivity) showed that the TBPM had a potential hazard of explosion. From the experimental results, the shock sensitivity and friction sensitivity was rated as class 4 and 5, respectively. In the pressure vessel test, TBPM was ranked USA-PVT No.4 and evaluated as a self-reactive substance. In the combustion rate test, TBPM had the combustion rate of 167 mm/sec and was evaluated as the flammable solid classification 2 in GHS.

• Journal of Electrical Engineering and Technology
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• v.4 no.1
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• pp.1-12
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• 2009

In recent years, integration of new distributed generation (DG) technology in distribution networks has become one of the major management concerns for professional engineers. This paper presents a dynamic methodology of optimal allocation and sizing of DG units for a given practical distribution network, so that the cost of active power can be minimized. The approach proposed is based on a combined Genetic/Fuzzy Rules. The genetic algorithm generates and optimizes combinations of distributed power generation for integration into the network in order to minimize power losses, and in second step simple fuzzy rules designs based upon practical expertise rules to control the reactive power of a multi dynamic shunt FACTS Compensator (SVC, STATCOM) in order to improve the system loadability. This proposed approach is implemented with the Matlab program and is applied to small case studies, IEEE 25-Bus and IEEE 30-Bus. The results obtained confirm the effectiveness in sizing and integration of an assigned number of DG units.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.193-194
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• 2015

국내의 경제 성장으로 전력 수요는 지속적으로 증가하고 있다. 지속적인 전력 수요의 증가는 계통의 전압을 일정하게 유지하기 어렵게 만들어 계통의 안정도를 감소시키므로 정전의 원인이 될 수도 있다. 무효전력은 계통의 전압과 안정도에 크게 관련이 있으므로 계통의 전압 유지와 안정 향상 방안 중 하나로 조상설비 투입을 고려 할 수 있다. 조상설비 투입 시 조상설비를 적절한 위치를 선정하여 투입하는 것은 중요하다. 본 논문에서는 전압 안정도 지표인 V-Q Sensitivity의 계통의 외란 발생 전후의 차를 새로운 안정도 지표로 제시하여 조상설비 투입 위치를 선정하는 방안에 대해서 제시를 하였고IEEE-30 계통을 이용하여 검토 하였다.

• Journal of Electrical Engineering and Technology
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• v.1 no.2
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• pp.161-169
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• 2006

Load representation has a significant impact on power system analysis and control results. In this paper, composite load models are developed based on on-line measurement data from a practical power system. Three types of static-dynamic load models are derived: general ZIP-induction motor model, Exponential-induction motor model and Z-induction motor model. For the dynamic induction motor model, two different third-order induction motor models are studied. The performances in modeling real and reactive power behaviors by composite load models are compared with other dynamic load models in terms of relative mismatch error. In addition, numerical consideration of ill-conditioned parameters is addressed based on trajectory sensitivity. Numerical studies indicate that the developed composite load models can accurately capture the dynamic behaviors of loads during disturbance.