• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.175-178
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• 1996

Power system is becomming more and more complex and large. So system is stressed increasingly. This paper presents a method to select contingency ranking in power systems for EMS operation. Firstly, the proposed method is applied line outage using Thevenin equivalent circuit. Secondly, Contingency harmful to system is selected by loss variation between base case and fault. Thirdly, this paper prescribed simulated line sequence. Therefore this algorithm shows higher computation speed and effective memory use.

• 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.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.73-76
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• 2001

This paper presents a new systematic contingency selection, screening and ranking method for on-line transient security assessment. Transient stability of a particular generator is influenced most by fault near it. Fault at the transmission lines adjacent to the generators are selected as contingency. Two screening methods are developed using the sensitivity of modal synchronizing torque coefficient and computing an approximate critical clearing time(CCT) without time simulation. The first method, which considers only synchronizing power, may mislead in some cases since it does not consider the acceleration power. The approximate CCT method, which consider both the acceleration and deceleration power, worked well. Finally the Single Machine Equivalent(SIME) method is implemented using IPLAN of PSS/E for detailed stability analysis.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.16 no.2
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• pp.1-11
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• 2008

Increasing demand for improved reliability and survivability of mission-critical systems is driving the development of health monitoring and Automated Contingency Management (ACM) systems. An ACM system is expected to adapt autonomously to fault conditions with the goal of still achieving mission objectives by allowing some degradation in system performance within permissible limits. ACM performance depends on supporting technologies like sensors and anomaly detection, diagnostic/prognostic and reasoning algorithms. This paper presents the development of a generic prototype test bench software framework for developing and validating ACM systems for advanced propulsion systems called the Propulsion ACM (PACM) Test Bench. The architecture has been implemented for a Monopropellant Propulsion System (MPS) to demonstrate the validity of the approach. A Simulink model of the MPS has been developed along with a fault injection module. It has been shown that the ACM system is capable of mitigating the failures by searching for an optimal strategy. Furthermore, the concepts of Validation and Verification (V&V) of such systems are introduced with relevant examples.

• 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 Korean Information Science Society Conference
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• 2004.04b
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• pp.403-405
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• 2004

인공위성 시스템은 기존의 임베디드 시스템과 달리 우주환경에서도 예측가능하며 견고히 수행되어야 하며, 또한 위성의 오류가 발생하게 되면 어떠한 환경에서도 위성의 생존을 위하여 자동적인 오류 검출. 오류 제거, contingency state로 위성을 재구성하는 과정이 반드시 필요로 한다. 이러한 모든 과정을 On-Board Fault Management라 하며, 본 논문에서는 다목적실용위성 2호의 On-Board Fault Management 구조와 오류 검출방식, 위성을 safing시키는 과정과 테스트 결과에 대해서 설명한다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1317-1325
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• 2016

This paper identifies the issues of contingency analysis for restoration in distribution systems. Contingency analysis has been applied to transmission systems but not to distribution systems. The distribution system is different from transmission system. So it is hard to apply for existing contingency analysis to distribution system. In this paper, a new contingency analysis method for distribution systems is proposed. The proposed method is based on service restoration capability. It aims to minimize outage left after service restoration in case of a fault in advance. The method estimates the vulnerability which is represented by zone restoration index proposed in [1]. Applying the proposed method, operators could change the system so that it does not leave any outage left after restoration. Case study has been carried out on a five feeder system and its results show effectiveness of the method.

• KIEE International Transactions on Power Engineering
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• v.2A no.4
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• pp.131-135
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• 2002

This paper describes a new ultra-fast contingency screening algorithm for on-line TSA without time simulation. All machines are represented in a classical model and the stability index is defined as the ratio between acceleration power during a fault and deceleration power after clearing the fault. Critical clustering of machines is done based on the stability index, and the power-angle curve of the critical machines is drawn assuming that the angles of the critical machines increase uniformly, while those of the non-critical ones remain constant. Finally, the critical clearing time (CCT) is computed using the power-angle curve. The proposed algorithm is tested on the KEPCO system comprised of 900-bus and 230-machines. The CCT values computed with the screening algorithm are in good agreement with those computed using the detailed model and the SIME method. The computation time for screening about 270 contingencies is 17 seconds with 1.2 GHz PC.

• 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.134-135
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• 2003

Abstract in case of the small scale power system separated from large scale power system N-2 contingency, the Over excitation, Under Frequency and Power swing Tripping Relay operate depending on unbalance Of Generation and Load. and then we studied and measured the angle and frequency deviation between generators. moreover, we compared real fault example with simulation results.