• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.175_176
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• 2009

K-WAMS based on i-PIU as a synchro-phasor data acquisition device using GPS can treat a monitoring and evaluation of wide area power system to detect a various symptoms of wide area disturbances and prevent large blackout. This paper introduced the development of K-WAMS such as WAMS(Wide Area Monitoring System).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.483-485
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• 2005

In 2003, there was a wide-area blackout in the United States and Canada. More than fifty million people underwent power failure and the estimated financial loss was about four billion dollars. By such wide-area blackouts, the interest in voltage stability has increased gradually. In order to maintain the voltage stability, the preventive control is essential for a contingency. In this paper, a proper preventive control is determined for defined severe contingencies. Among the preventive control methods (generation rescheduling, load curtailment, tap adjusting, injecting the shunt capacitor, and so on.), this paper presents the injection of shunt capacitors by the sensitivity analysis of the voltage stability assessment for preventive controls. The 2006-2010 KEPCO summer peak system is used in case studies.

• 한국전자통신학회논문지
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• 제17권3호
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• pp.441-448
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• 2022

배전분야 전력계통에 적용되는 보호기기류는 변전소 차단기, 배전선로의 리클로저, 최소 전류 용량 회로, 고장구간 차단기 등이 있다. 이들은 부분 정전이나 대규모 사고를 방지하고 선로의 순간고장 또는 영구고장 발생 시 정상 계통이 건전성을 유지할 수 있도록 광역 정전 파급을 방지한다. 그러나 사고가 발생할 경우 변전소 차단기와 배전선로 보호기기 간의 보호협조 미비로 인하여 광역 정전을 초래할 수 있다. 더 좋은 전력시스템의 건전성을 확보하기 위하여 1주기(16ms) 이내로 동작하는 차단기를 개발할 필요성이 요구된다. 본 연구에서는 친환경 가스절연 방식의 고속도 차단기를 개발하였으며, IEC 62271-111 표준에 기반한 시험에서 우수한 결과를 얻었다. 이 기기는 고장구간을 정확하고 빠르고 신속하게 분리하여 광역 정전 예방에 기여할 것으로 기대된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.223-225
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• 2001

When a wide area blackout occurres, reenergizing transmission lines should be done at first. The KEPCO(Korea Electric Power Corporation) divides whole power system grid Into seven subsystem. This paper describes the investigation of facts, such as voltage rising and system stability, which occur in case that the blackstart plant of the Honam area will be displaced from Juam H/P to Seojingang H/P.

• 전기학회논문지
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• 제59권9호
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• pp.1530-1539
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• 2010

Recent technology advancement related to computer & communication and measuring devices allows system operators to adopt more intelligent monitoring and control systems to their power systems in order to prevent massive system blackout. Among them, wide-area monitoring and control(WAMAC) system based on synchro-phasor technology has been widely applied to power systems for their own purposes. In this paper, the study on the development of load shedding scheme to improve voltage stability in KEPCO system is introduced. Summary of WAMAC technology being developed and applied in the world through extensive literature survey is proposed. And methodology to develop voltage stability index and multi-step load shedding scheme based on synchro-phasor data is also presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.220-222
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• 2005

Power system restoration following a wide area or complete blackout starts with energizing primary restorative transmission systems. During this primary restoration process, unexpected over-voltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. This is known as the harmonic resonance phenomenon that may cause burning out of transformer or other devices. Since the harmonic resonance originates from the nonlinear characteristics, it is very difficult to predict the occurrence of this phenomenon. This paper reports the possible existence of the harmonic resonance in Korean power system. Analysis of the harmonic over-voltage is presented based on the various simulations using PSCAD/EMTDC.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.12-14
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• 2006

This paper presents an vulnerability index for hidden failure of protective relays in transmission system. The bad influence can be quantized by an vulnerability index. When there is mis-operation, no-operation or mis-setting, power flow can be quantized by an index. According to the index, relays can be resetting. So the wide area blackout can be prevented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.269-271
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• 2006

In power system, the reactive power is closely associated with voltage. In addition Reactive power has localized characteristic. Recently wide area blackout caused by reactive power imbalance. Therefore it is important to control reactive power considering its characteristic. Until now maintenance of system voltage has been controlled by shunt compensation rather than generators. However because of a large time-constant, shunt compensators are difficult to manage disturbances immediately. In addition shunt compensation has discrete characteristic, which make disturbances in system. In this paper we studied the voltage maintenance method of local buses by controlling the reactive power output of a generator which is closely related a load bus in addition the proposed method was verified by test system.

• 전기학회논문지P
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• 제63권1호
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• pp.1-6
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• 2014

An electric power system sometimes fails because of disturbances that occur unexpectedly, such as the uncontrolled loss of load that developed from cascading blackout. Which make stability through a little of under voltage load shedding should work. The development of phasor measurement unit(PMU) makes network supervision possible. The information obtained from PMU is synchronized by global positioning system(GPS). There are many real-time algorithms which are monitoring the voltage stability. This paper presents the study on the VILS(Voltage Instability Load Shedding) using PMU data. This algorithm computes Voltage Stability Margin Index(VSMI) continuously to track the voltage stability margin at local bus level. The VSMI is expressed as active and reactive power. The VSMI is used as an criterion for load shedding. In order to examine the algorithm is effective, applied to KEPCO system.

• 대한전기학회논문지:전력기술부문A
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• 제55권5호
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• pp.191-194
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• 2006

Power system restoration following a wide area or complete blackout starts with energizing primary restorative transmission systems. During this primary restoration process, unexpected over-voltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. This is known as the harmonic resonance phenomenon that may cause burning out of transformer or other devices. Since the harmonic resonance originates from the nonlinear characteristics, it is very difficult to predict the occurrence of this phenomenon. This paper reports the analyses of the harmonic resonance occurred in domestic power system. Various analyses and results of the harmonic over-voltage is presented based on the PSCAD/EMTDC simulations.