• Proceedings of the KIEE Conference
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• summer
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• pp.610-612
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• 2004

Because the overhead transmission lines are exposed to the outdoor weather, the faults of the transmission lines are due to natural conditions, and among these faults, the outage rate by lightning is about $50\%$. Therefore, the insulation design is important to decrease the damage of the facility and to increase the reliability of electric power system. This paper describes the protective method of substation equipments using the Underbuilt Ground Wire and the Guy Wire. This would not only reduce backflashover possibility but also minimize crest and duration of surges entering the substation. EMTP is used to analyze the efficiency of the proposed methods.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1611-1617
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• 2015

This paper presents an effective approach for establishing countermeasures against voltage sags based on the concept of area of severity. In order to apply preventive measures against faults such as lightning arrester, overhead earth wires and so on, it is important to find optimal points for installing the preventive measures. The optimal points can be determined by the calculation of the area of severity(AOS) to voltage sags and the expected sag frequency per unit length of line. In this paper, an effective method to find optimal points to apply countermeasures against voltage sags is addressed with case studies.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.162-168
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• 2009

This paper describes a study that is to redesign insulation of transmission lines and determine required the numbers of insulators in order to enhance the insulation performance of existing transmission lines which were constructed with standard insulation design, considering overvoltage analysis results, probabilities and characteristics of faults. To ensure proper insulation distance without deteriorating the required performance, EMTP model is established to calculate maximum overvoltage in the line. The fault records and predicted outage rates due to lightning and contamination in the line were investigated and analyzed respectively. It presents a method to determine the numbers of insulators considering the probability and the characteristic of fault.

• Journal of the Society of Disaster Information
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• v.20 no.3
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• pp.541-548
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• 2024

Purpose: This study aims to compare the grounding methods of transformers currently used in most industrial sites in Korea to analyze the stability of power quality and the risk of electric shock. Method: The ungrounded method allows for continuous power supply even in the event of a single-phase ground fault, resulting in a lower risk of electric shock. In contrast, the solidly grounded method focuses on quickly cutting off power during incidents such as ground faults or lightning strikes to protect load equipment, as explained through literature comparison. Result and Conclusion: It is concluded that the ungrounded method is preferable in environments where continuous power supply is essential.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.471-472
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• 2011

최근 10여년간 기후변화로 인한 낙뢰빈도와 낙뢰크기가 증가추세로 분석되고 있으며 이로 인해 한전의 전력설비는 낙뢰고장 점유율이 크게 증가하고 있다. '96년~'00년 사이에 59.3%이었던 낙뢰고장 점유율이 최근 5개년('06~'10년)사이에 무려 80.3%에 이르고 있는 실정이다. 또한 민원으로 인한 산악지 경과 및 4회선 송전철탑의 증가로 낙뢰 고장의 개연성은 계속 증가하고 있다. 따라서 본 논문에서는 실제 한전설비에 발생했던 과거 10년간의 고장자료를 심층 분석하여 낙뢰고장을 감소시킬 수 있는 개선 아이디어를 도출하고 향후 낙뢰고장 분석에 필요한 추가 핵심인자를 발굴해보고자 한다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.469-470
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• 2011

최근 15년간의 우리나라에 발생했던 낙뢰데이터를 분석해 보면 매년 낙뢰빈도와 낙뢰크기가 증가하고 있다. 154kV 송전선로의 경우 낙뢰고장률이 '01년도 0.93건/c-km 년에서' 10년도 2.75건/c-km 년으로 급증하였다. 이에 낙뢰고장을 저감하기 위한 다방면의 검토가 요구되고 있다. 본 논문에서는 낙뢰고장 저감 대책 중 하나로 낙뢰고장의 다수를 차지하고 있는 역섬락을 감소시키기 위하여 역섬락을 발생시키는 절연거리를 증가시키는 방안을 검토해보고자 한다. 또한 현재 운영 중인 아킹혼 설치기준 및 애자련 보호효과 등에 대해서도 체계적인 검토가 필요한 시점이다.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.147-148
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• 2008

본 논문에서는 154 kV 송전선포의 낙뢰고장기록과 선로주변의 낙뢰측정기륵을 분석하여 상관관계를 분식하였다. 낙뢰관측기록과 고장의 위치, 시각과 고장 메카니즘의 규명은 선로의 합리적인 대책수립에 유용한 정보를 제공할 수 있다. 6년간의 LPATS 및 KLDNet 관측기록과 송전고장기록을 이용하여 EMTP 해석모델과 뇌사고율 해석 S/W를 사용하여 뇌섬락 임계전류를 계산하고 뇌고장 유형을 분석 하였다.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.12
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• pp.561-565
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• 2001

Recent trend of increasing automated factories needs supply of high quality power from the utilities. Among the items of the power quality, voltage sag can be compensated by Dynamic Voltage Restorer(DVR). The key feature of the DVR is high response with less transient period to recover from the voltage sag due to the lightning or line-to-ground faults. In this paper we report that $H_{\infty}$ controller is very promising for the practical application to the controller of DVR. Experimental results shown in this paper was obtained by applying the control algorithm to 20 kVA DVR system. The experimental set consists of IGBT-based three phase inverter and the TMS320C32-60 DSP used for main processor of the control board. To simulate the 50% voltage sag, the SCR-based experimental set was constructed.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.455-461
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• 2002

가공 송전선로의 낙뢰고장은 송전설비가 국토 전 지역에 분포되어 있기 때문에 고장 점유율이 가장 높다. 또한 낙뢰가 아주 큰 전기량과 짧은 순간에 방전하는 특성뿐 아니라 다양한 구름의 변화형태에 따른 낙뢰 발생 패턴이 달라 아직까지 이를 예방하거나 제어하는 기술은 높지 않은 수준에 있다. 이 논문은 자연환경이 비슷하고 전압레벨과 전력계통이 유사한 한국전력(KEPCO)과 대만전력(TPC)의 6년간의 송전선로 낙뢰고장을 통계적으로 비교하여 낙뢰고장과 전력신의 차례각과의 관계적 원인을 도출하고자 하였다. 이에 따라 전력선의 차폐각에 따른 낙뢰고장 발생 확률을 시뮬레이션 프로그램을 통하여 도출하고 실제 양 전력회사의 차폐각별 송전선로의 낙뢰고장 발생빈도와 비교하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.26-26
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• 2010

Line to ground faults or lightning strikes in electrical power systems produce high frequency overvoltages. With this reason, a wide band analysis of the ground impedance is necessary. In the paper, design of a wideband ground impedance meter which can measure the ground impedance in ranges from 65 Hz to 1.5 MHz is described. Also, a noise elimination method by a digital band-pass filter during measurement is proposed. The maximum measurement error of the meter is estimated 3 % in full ranges.