• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.451-452
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• 2007

In this paper, we simulate power system transient stability using object-oriented programming(OOP). OOP is a more flexible method than procedual programming. There are several advantages in dynamic system simulation using OOP. We also calculate critical fault clearing time using energy functions for detailed models.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2388-2392
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• 2013

Wind generation systems are very different in nature from conventional generation systems. Therefore it is necessary to research dynamic characteristics of wind generation systems connected to a power system. The stability analysis of wind turbine generator is an important issue in the operation of the power system. The result of angular stability of the power system that consists of only synchronous generators is different from that of the power system including wind turbine generators. This is due to the fact that generators connected to wind turbines are generally induction generators. The angular stability assessing synchronization of generators is determined by its corresponding critical clearing time(CCT). Wind turbine models for the analysis of power system are varied and difficult to use, but now these are standardized into four types. In this paper, the analysis of the CCT of the power system connected to wind farm considering the location and capacity is performed by using DFIG(Doubly-Fed induction Generator) wind turbine built-in type3 model in PSS/E-32.

• KIEE International Transactions on Power Engineering
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• v.11A no.4
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• pp.15-20
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• 2001

Power system stability is correlated with system structure, disturbances and operating conditions, and power flows on transmission lines are closely related with those conditions. This paper proposes a methodology to identify correlative power flows for power system transient and small-signal stability prediction. In transient stability sense, the Critical Clearing Time is used to select some dominant contingencies, and Transient Stability Prediction index is proposed for the quantitative comparison. For small-signal stability discusses a methodology to identify crucial transmission lines for stability prediction by introducing a sensitivity factor based on eigenvalue sensitivity technique. On-line monitoring of the selected lines enables to predict system stability in real-time. Also, a procedure to make a priority list of monitored transmission lines is proposed. The procedure is applied to a test system, and it shows capabilities of the proposed method.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.5
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• pp.271-278
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• 2003

Power system stability is correlated with system structure, disturbances and operating conditions, and power flows on transmission lines are closely related with those conditions. This paper proposes a methodology to identify correlative power flows for power system transient and small-signal stability prediction. In transient stability sense, the Critical Clearing Time is used to select some dominant contingencies, and Transient Stability Prediction index is proposed for the quantitative comparison. For small-signal stability, this paper discusses a methodology to identify crucial transmission lines for stability Prediction by introducing a sensitivity factor based on eigenvalue sensitivity technique. On-line monitoring of the selected lines enables to predict system stability in real-time. Also, a Procedure to make a priority list of monitored transmission lines is proposed. The procedure is applied to a test system and the KEPCO systems in the year of 2003 and it shows capabilities of the proposed method

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.10
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• pp.89-96
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• 2015

Explicit numerical integration methods for power system transient stability simulation require very small time steps to avoid numerical instability. The EXST1 exciter model is a primary source of fast dynamics in power system transients. In case of the EXST1, the required small integration time step for entire system simulation increases the computational demands in terms of running time and storage. This paper presents a practical exciter model reduction approach which allows the increase of the required step size and thus the method can decrease the computational demands. The fast dynamics in the original EXST1 are eliminated in the reduced exciter model. The use of a larger time step improves the computational efficiency. This paper describes the way to eliminate the fast dynamics from the original exciter model based on linear system theory. In order to validate the performance of the proposed method, case studies with the GSO-37 bus system are provided. Comparisons between the original and reduced models are made in simulation accuracy and critical clearing time.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.213-214
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• 2016

중요부하를 갖는 ESS용 인버터는 정전 발생 시에도 부하에 안정적인 전원을 공급해야 한다. 이를 위하여 모드전환 시 과도상태를 최소화하면서 clearing time에도 부하에 안정적인 전압을 공급할 수 있는 간접전류제어 기법이 연구된 바 있다. 그러나 계통연계 시에도 전압을 제어해주기 때문에 단독운전 시 NDZ을 벗어나지 않아, 기존 알고리즘으로는 단독운전을 검출하기 어렵다는 문제가 있다. 본 논문에서는 모드 전환 시 과도상태를 최소화하면서 단독운전 검출 전에도 부하 전압을 안정하게 제어할 수 있는 간접전류제어 기반 인버터에서 NDZ이 없는 무효전력 P&O 단독운전 검출 기법을 제안한다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1897-1904
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• 2008

In this paper, the method for effective stability analysis of Jeju power system in 2011 is proposed. The stability analysis of Jeju power system was carried out by using proposed method In case of Jeju power system with wind turbine generators or without wind turbine generators, including CSC HVDC or VSC HVDC. The steady-state stability is validated by SCR and ESCR, PV curve, QV curve. And the transient stability is analyzed by CCT(Critical Clearing Time). VSC HVDC has more advantages than CSV HVDC on the stability. Also, Jeju power system without wind turbine generators has more advantages than Jeju power system with Wind Turbine Generators on the stability.

• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.337-345
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• 2008

This paper presents a new approach to the design of a rough fuzzy controller for the control loop of the SVC (static VAR system) in a two area power system for stability enhancement with particular emphasis on providing effective damping for oscillatory instabilities. The performances of the rough fuzzy and the conventional fuzzy controller are compared with that of the conventional PI controller for a variety of transient disturbances, highlighting the effectiveness of the rough fuzzy controller in damping the inter-area oscillations. The effect of the rough fuzzy controller in improving the CCT (critical clearing time) of the two area system is elaborated in this paper as well.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.535-536
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• 2006

This paper reports investigation into the factors that influence the transient behavior of the wind power generation system following network fault conditions. It is shown that the critical clearing time(CCT) can be affected by various factors contributed by the host network. Such factors include capacity of wind power, power factor, the length of the interfacing line, etc. This investigation is conducted en a simulated grid-connected wind farm using Digsilent Power Factory.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1109-1111
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• 1997

The purpose of this paper is to analyze the effects of switching-over control for power system stabilization. Switching-over control is applied to western part of korea electric power system to improve transient stability and short-circuit capacity. It's effectiveness is demonstrated in terms of fault current level and critical clearing time which is quantitative evaluation means of transient stability. The effect of generator tripping for power system stabilization is also presented.