• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.111-113
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• 2002

본 논문에서는 경쟁적 전력시장에서 송전 계약에 관한 비용을 모선에서 한계비용 만감도를 이용해서 분할하는 방법을 제시하였다. 구조개편된 전력사장에서는 단순하면서도 분명한 전력 요금 시스템이 요구된다. Zonal pricing은 이런 면에서 좋은 pricing 시스템이 요구된다. 하지만, zone을 효과적으로 나누는 것은 상당히 어렵다. 기존의 방법에서는 오직 부하만을 고려하여 분류를 하였지만, 에너지 시장에서의 전력의 매매행위를 고려할 때, 시스템 내부의 모든 사업자에 대한 고려가 필요하다. 그래서, 본 논문에서는 한계비용 민감도를 이용해서 모든 에너지 시장 참여자를 고려하여, 네트워크를 분할하였다. 모든 노드에서의 민감도의 패턴이 분석되었고 동일한 패턴을 가진 노드들을 같은 zone으로 분류하였다. 6-모선 전력시스템을 이용해서 제안한 방법을 설명하였다.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.169-171
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• 1992

In an automated power distribution systems, the fault situation is controlled from the control center through remotely-controlled sectionalizing switches. In this paper, the service restoration strategy which can yield the minimal switching actions and constraint checking is proposed and an expert system which generates the appropriate switching actions is described.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.900-902
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• 1997

Stabilization of Power systems is investigated using a proportional-integral power system stabilizer(PI PSS). Time division PI PSS is examined in this paper. Two approaches are presented for determining the optimal stabilizer gains of the proposed PI PSS. Simulation results show that the proposed PI PSS yields better system dynamic performance and stability than the sub-optimal stabilizer in the sense of having greater damping in response to a step disturbance.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.11
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• pp.387-393
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• 1983

This paper descrives the computational algorithm for determination of system characteristic constants using diakoptic method. When the system charateristic contants of large scale power system are calculated by using sensitivity matrix method which requires the inversion of Jacobian matrix, the necessary computing time and memory requirements increase very largely. Diakoptic mothods is benefit to get around these problems, and it is applied to a model system compared with the integrated method to discuss the efficiency of the algorithm.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.802-803
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• 2007

전력산업의 구조개편에 따라 현재 전력시스템은 안전도의 위협수준에 가깝게 운영되어지도록 강요받고 있다. 이러한 시대적 흐름에 의해 안전도(security)해석에 대한 보다 빠르고 정확한 연구가 중요시 되고 있다. 본 연구는 전력시스템의 안전도 해석에 있어 상정사고(contingency)를 고려할 때 클러스터링 기법을 이용한 송전 네트워크의 축약 알고리즘을 제안한다. 또한 PC 클러스터 시스템을 이용한 병렬처리기법을 이용한 상정사고의 분할연산을 수행하고자 한다. IEEE 39 모선시스템을 통해 제안된 알고리즘을 평가할 것이다.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.145-156
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• 1988

This study was conducted to investigate the effect of embryo stage on bisection rates of embryos, on development of separated demi-embryos and on subsequent development to full term following transfer of demi-embryos to recipients. The results obtained in this study are summarized as follows. The 2-, 4-, 8-cell and morula embryos were mostly obtained at 36-42, 48-54, 62-66 and 72-78 hours after injection of hCG, respectively, and the average number of embryos recovered per head was 17.0. The bisection rate of 8-cell embryos was 83.6%, which was significantly higher than that of morula embryos, 65.5%. But the development of morula demi-embryos to blastocyst after in-vitro culture was better than that of 8-cell demi-embryos and the rate was 76.5% and 60.9%, respectively. When the 2, 10 and 15 cultured demi-embryos or intact embryos were transferred to each recipient mouse, respectively. the highest pregnancy rate was obtained when 15 embryos were transferred. And the overall offspring production rate of intact embryos was higher than that of demi-embryos.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.4
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• pp.428-433
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• 2010

According as economy grows, demand for power increases and satisfaction of customer about electricity quality is rising. There is in trend that investment expense by continuously increased supply of electric power equipment is on the increase continuously, but management efficiency improvement through curtailment of supply of electric power equipment investment expense through efficient operation is required rather than to increase investment. In this study, reconsidered about 6 divisions 3 ties that is distribution line basis configuration of Daejeon Geumsan area and analyzed division and tie present condition of truthful distribution System. Examined problem analyzing average division number, tie number and tie switch number, searched about most suitable division that consider load. Hereafter, I wish to take advantage of analysis result in most suitable division and tie of truthful distribution system for power failure section reduction and investment expense curtailment.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.1
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• pp.1-9
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• 1990

The structure of A matrix of one machine connected to the infinite bus is described for a full model. The A matrix can be partitioned to submatrices which depend on the initial operating point and do not depend on it. When the dynamic properties for several different operating points are desired, those submatrices can be obtained through simple column operation. Furthermore, the elements of A matrix can be directly calculated from the manufacturer's data. RMS quantities of the state variables for the initial operating point are used. This approach can save the labor for calculating the elements of A matrix for the dynamic stability analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.239-249
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• 2019

Recently, the Korean government has implemented a policy to expand renewable energy sources. Large-scale PV systems are being actively interconnected with the distribution system. On the other hand, when a large-scale PV system is installed and operated, the customer voltages could violate the allowable voltage limit due to reverse power flow of the PV system. To overcome these problems, an enhancement method for hosting the capacity of the PV system in a distribution system is being actively conducted. Therefore, to improve the hosting capacity of the PV system, this paper proposes a model of a reconfiguration of the distribution system, which is composed of three sections and three connections based on PSCAD/EMTDC S/W, and proposes an evaluation algorithm for the feeder reconfiguration to maximize an adaption of the PV system. In addition, this paper presents the optimal method of the feeder reconfiguration section to evaluate the maximum capacity of the PV system to keep customer voltages within the allowable voltage limits based on various operation scenarios, such as the capacity of a PV system and section of feeder reconfiguration. From the simulation results based on the PSCAD/EMTDC modeling and evaluation algorithm, it was confirmed that they are a useful and practical tool to enhance hosting the capacity of a PV system in a distribution system.

• Proceedings of the Korea Society for Simulation Conference
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• 2000.11a
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• pp.61-66
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• 2000

The KEPRI has been upgrading the KNPEC(Korea Nuclear Power Education Center) #2 simulator, a replica of Yonggwang Unit 1 & 2, due to the outdated systems. The scenarios, such as the continuous load change, are selected to verify and validate the simulator, and the data required to V&V are generated with the best-estimated codes, RETRAN and MARS. The reactor coolant system and steam generator system are cut up into volumes and junctions for the accurate model of the scenarios, and other components and control systems are modeled. For the model the operation and design data of the plants is used and in some cases the data of Kori Unit 3 & 4 is used to fill up the lack of required data. The results of some selected analyses with the models are compared with the operating data of the plants to verify the models, and the analyses of the scenarios are carried out to generated the data for the V&V of the simulator