• Journal of the Korean Solar Energy Society
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• v.34 no.2
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• pp.91-97
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• 2014

This paper presents the modeling and contingency analysis of Jeju power system. For the analysis of contingency with simulation, thermal power plants, current source type HVDC systems, wind farms, STATCOMs and Jeju power load are modeled by PSCAD/EMTDC program. And three kinds of simulation are carried out. Firstly, two STATCOMSs are in normal operation. Secondly, one STATCOM is in fault. Lastly, all of STATCOMs are in fault. These comparative studies will be useful for evaluating the effectiveness of STATCOM to stabilize for the Jeju power system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.5
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• pp.309-318
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• 1987

In the on-line security analysis of power system, Automatic Contingency Selection (ACS) is commonly used to reduce the number of contingency cases which will be evaluated in detail. This paper describes a fast and reliable ACS method which adopts DC load flow in conjunction with compensation theorem to improve execution time, and applies severity performance index, divided on each limit level for considering overload rate, to make reliable contingency ranking. The method has been tested in IEEE 25 bus system and KEPCO 130 bus actual power system. The results of these tests verify its superiority to both the execution time and reliability, and illustrate its effectiveness for the practical use.

• Korean Journal of Logic
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• v.12 no.2
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• pp.1-29
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• 2009

According to Field, mathematical objects do not exist but they might have existed. In this paper I examine how persuasive this 'contingent' nominalism could be. For this I give a detailed analysis of the recent debate on the contingency of mathematical objects. I argue that the putative connection between contingency and explanation could still be sustained, but an independent argument is needed in order to support a general principle underlying the connection. I show that the attacks based on the anti-insularity principles already reflect their own positions on the modal status of the existence of mathematical objects.

• Korean Journal of Logic
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• v.14 no.1
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• pp.103-118
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• 2011

In his paper "The Existence of Mathematical Objects and Contingency" Professor Choi deals with the debate between Hartry Field and Hale/Wright. In this famous debate, Hale/Wright and Field argue back and forth about whether some explanations for the contingency of mathematical objects need to be provided or not. In this paper, I raise 3 objections to Professor Choi's critical analysis of this debate.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.139-141
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• 2002

This paper describes a new contingency analysis methods for small signal security assessment based on the eigenvalue perturbation. The eigenvalue perturbation with respect to MW changes can be used to find possible sources of the low frequency oscillation, and to select contingency for small signal stability. The proposed algorithm has been successfully tested on the KEPCO systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.8
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• pp.994-1001
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• 2018

In this paper, to studied about future power system construction using PSS / E-Python API. Python-based future system automatical construction methods and modeling of renewable sources. it confirmed the stability of the powert system for each renewable area by calculating the weighted short circuit ratio (WSCR) index. it calculated the short circuit ratio (SCR) and selected the transmission line linkage scenario to improve the stability of vulnerable areas. it confirmed the WSCR index improvement through the selected transmission line linkage of scenario, and analyzed the stability of the renewable power system applying the scenario. It describes Facts and Shunt devices adjustment for the load flow convergence. It describes the stable methed of the bus voltage through the transformer Ratio Tap adjustment. By performing PSS/E ASCC using the Python it was performed three-phase short circuit fault capacity analysis, it is confirmed whether excess of the fault current circuit breaker capacity. In order to contingency accident analysis, it have described the generation of one or two line list of each areas using the Python. The list is used to contingency analysis and describe the soluted of the transmission line overload through comparison before and after adding the scenario line.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.318-320
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• 2015

The distribution system is operated radially in which electrical grid is complex. If a fault occurs in distribution system, it can make a huge impact on power supply. Therefore, The distribution contingency analysis is proposed in this paper based on the reference [1]. Using RSI (Restoration Section Index) calculated by feeder margin and section load, the operator can grasp restoration capability quickly.

• Proceedings of the KIEE Conference
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• 2003.07a
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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.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.338-343
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• 2013

Integrated Project Delivery (IPD) as a delivery method fully capitalizes on an integrated project team that takes advantage of the knowledge of all team members to maximize project outcomes. IPD is currently the highest form of collaboration available because all three core project stakeholders, owner, designer and contractor, are aligned to the same purpose. Compared with traditional project delivery approaches such as Design-Bid-Build (DBB), Design-Build (DB), and CM at-Risk, IPD is distinguished in that it eliminates the adversarial nature of the business by encouraging transparency, open communication, honesty and collaboration among all project stakeholders. The team appropriately shares the project risk and reward. Sharing reward is easy, while it is hard to fairly share a failure. So the compensation structure and the contingency in IPD are very different from those in traditional delivery methods and they are expected to encourage motivation, inspiration and creativity of all project stakeholders to achieve project success. This paper investigates the compensation structure in IPD and provides a method to determine the proper level of contingency allocation to reduce the risk of cost overrun. It also proposes a method in which contingency could be used as a functional monetary incentive when established to produce the desired level of collaboration in IPD. Based on the compensation structure scenario discovered, a probabilistic contingency calculation model was created by evaluating the random nature of changes and various risk drivers. The model can be used by the IPD team to forecast the probability of the cost overrun and equip the IPD team with confidence to really enjoy the benefits of collaborative team work.

• Korean Journal of Construction Engineering and Management
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• v.20 no.5
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• pp.125-136
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• 2019

This study investigated checked risk level before bid, actual risk level after award, contingency, and cost growth rate in the 124 international construction projects executed by Korean major companies. This study conducted comparative analysis by product type using rank analysis, ANOVA and correlation analysis. As a result, plant and civil projects have worse risk level than architecture projects not only in before bid but also in after award. Especially, country risk is the worst risk in both plant and civil projects, followed by project risk and capability risk. Also, although plant and civil projects reflect more contingency than architecture projects, contingency is not correlated with the checked risk level before bid. Lastly, the cost growth rate is correlated with the actual risk level in all product types. This study is expected to support in planning better practical risk management for international construction projects.