• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.347-349
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• 2005

This paper presents an efficient algorithm to estimate the maximum load level for heavily loaded power systems with the load-generation variation vector obtained by ELD (Economic Load Dispatch) and/or short term load forecasting while utilizing the elliptic pattern of the P-e curve. It is well known the power flow equation in the rectangular coordinate is fully quadratic. However, the coupling between e and f makes it difficult to take advantage of this quadratic characteristic. In this paper, a simple technique is proposed to reflect the e-f coupling effects on the estimation of maximum loadability with theoretical analysis. An efficient estimation algorithm has been developed with the use of the elliptic properties of the P-e curve. The proposed algorithm is tested on IEEE 14 bus system, New England 39 bus system and IEEE 118 bus system, which shows that the maximum load level can be efficiently estimated with remarkable improvement in accuracy.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.5
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• pp.272-281
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• 1988

The problem of optimal transmission system planning is to find the most economical locations and time of transmission line construction under the various constraints such as available rights-of-way, finances, the technical characteristics of power system, and the reliability criterion of power supply, and so on. In this paper the constraint of right-of-way is represented as a finite set of available rights-of-way. And the constructed for a unit period. The electrical constraints are represented in terms of line overload and steady state stability margin. And the reliability criterion is dealt with the suppression of failure cost and with single-contingency analysis. In general, the transmission planning problem requires integer solutions and its objective function is nonlinear. In this paper the objective function is defined as a sum of the present values of construction cost and the minimum operating cost of power system. The latter is represented as a sum of generation cost and failure cost considering the change of yearly load, economic dispatch, and the line contingency. For the calculation of operating cost linear programming is adopted on the base of DC load flow calculation, and for the optimization of main objective function nonlinear Branch-and-Bound algorithm is used. Finally, for improving the efficiency of B & B algorithm a new sensitivity analysis algorithm is proposed.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.8
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• pp.379-384
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• 2002

In the competitive electricity market, various pricing methods are developed and practiced in many countries. Among these pricing methods, marginal loss factor(MLF) can be applied to reflect the marginal cost of network losses. For the calculation of MLF, power flow method has been used to calculate system loss deviation. However, this power flow method shows some shortcomings such as necessity of regional reference node, and absence of an ability to consider network constraints like line congestion, voltage limit, and generation output limit. The former defect might affects adversely to the equity of market participants and the latter might generate an inappropriate price signals to customers and generators. To overcome these defects, the utilization of optimal power flow(OPF) is suggested to get the system loss deviation in this paper. 30-bus system is used for the case study to compare the MLF results by the power flow and the OPF method for 24-hour dispatching and pricing, Generator payment and customer charge are compared with these two methods also. The results show that MLF by OPF reflects the power system condition more faithfully than that of by the conventional power flow method

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.801-813
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• 2023

The events at Three Mile Island in the United States brought about fundamental changes in the ways that simulation would be used in nuclear operations. The need for research simulators was identified to scientifically study human-centered risk and make recommendations for process control system designs. This paper documents the human factors research conducted at the Human Systems and Simulation Laboratory (HSSL) since its inception in 2010 at Idaho National Laboratory. The facility's primary purposes are to provide support to utilities for system upgrades and to validate modernized control room concepts. In the last decade, however, as nuclear industry needs have evolved, so too have the purposes of the HSSL. Thus, beyond control room modernization, human factors researchers have evaluated the security of nuclear infrastructure from cyber adversaries and evaluated human-in-the-loop simulations for joint operations with an integrated hydrogen generation plant. Lastly, our review presents research using human reliability analysis techniques with data collected from HSSL-based studies and concludes with potential future directions for the HSSL, including severe accident management and advanced control room technologies.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.3
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• pp.377-382
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• 2016

In 2013, a total capacity of 591.3 MW of installed wind power generation was achieved in Korea, with a total of 1,139 MWh of wind energy generated that year. More wind power plants will be installed in the coming years, and it is important to develop methods to reduce the output variability of these resources so as to provide stable power to the power grid of Korea. In this regard, this paper proposes the use of energy storage system (ESS) as a means to stabilize the output variability of wind power plants. Presented in this paper is a method that uses Discrete Fourier Transform (DFT) to determine the ESS capacity needed to provide a stable power output for ancillary services such as frequency regulation, economic dispatch, and emergency reserves. In the first step of the proposed method, four regions (namely, Samdal, Yeongdeok, Yeongyang, and Gangwon) in Korea that had the most wind power generation capacity were selected for analysis. In the second step, the individual and aggregated wind power outputs of the selected regions in 2013 were obtained This information was then used in the third step, where DFT analysis of the power outputs was used to drive the magnitudes of the output variation. And finally, the ESS capacity requirements needed to provide different ancillary services were determined based on the magnitudes of the output variation.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2521-2532
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• 1997

The next generation internet protocol, IPv6, have been developed by the IETF according to the requirements of enhancement of classic IP protocols to satisfy the lack of Internet address space as well as the support of multimedia applications. This paper presents an implementation of IPv6 protocols on the Windows NT kernel environment. In this work, we developed and also tested the basic functions, required for operating as an IPv6 host, such as IPv6 header processing, IPv6 address handling, control message processing, group membership processing and neighbor discovery functions. The implemented IPv6 protocol driver module is connected to the lower network interface card through NDIS, a standard network interface. And this driver module that operates within kernel, is implemented as it is connected to upper user applications and lower NDIS using dispatch and lower-edge functions. The developed IPv6 protocol driver can provide not only enhanced performance because it is implemented in kernel mode, but also convenience of usage to the application developers because it gives user interface as a dynamic link library.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.2
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• pp.299-308
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• 2022

Recent, energy transition policies are driving to increase in the number of small photovoltaic(PV) generators. It is difficult for system operators to accurately anticipate the amount of power generated from such small scale PV generation, and this may disrupt dispatch schedules and result in an increase in cost. The need for a Virtual Power Plant(VPP) is emerging as a way of resolving these problems, as it would integrate small-scale PV plants and eliminate uncertainty about the amount of power generated, control voltage, and provide power reserves. In this paper, the cost evaluation methods are described for determination of VPP cloud charges both Net Present Value(NPV) method and Profitability Index(PI) method, the calculated outcomes of the two types of cost evaluation methods are presented in detail. It seems we secure profitability as we get 1.22 of profitability index from calculation results, it may be attractive for the aggregator as NPV is enough for satisfying profitability.

• Journal of the military operations research society of Korea
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• v.34 no.3
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• pp.31-40
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• 2008

The aircraft manufacturing industry is a profitable business and has the potential to be an important export business. Our trade deficit needs to be improved in aircraft manufacturing part. Our national aircraft industry, which has been recognized for its quality in many domestic and international Air Shows, has developed the T/A-50 aircraft from the origins of the KT-1. With the ongoing development of the next generation fighter planes and helicopters, business for the next generation domestic air cargo has bright prospects. Judging by the history of the overseas air force dispatch during the Vietnam, Gulf, and Iraqi wars whose main mission was air transportation, there will be many opportunities to show the excellence of Korean air cargo in the future. The purpose of this study is to discover the optimal scale of air cargo development using the AHP method. The authors evaluated the scale of air cargo in size and capacity based on the following 5 standards used Korean developing airliner: usability, economics, technology, safety, and environmental friendliness. Then, the authors modified specific standards suitable for air cargo based on literature review Decision-making groups were chosen for suitability of expert staff in charge because they could represent for leading opinions in this specialized area especially as in practical aspects. The participants of the evaluation were pilots, transportation officers and management staff in the KAI who have experienced over 5years.