• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.306-309
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• 1995

This paper describes the dielectric characteristics of $SF_{6}$ gas in a non-uniform electric field under overvoltages. The breakdown voltage-time characteristics and the breakdown voltage-gas pressure characteristics are measured within a gas pressure range extending from 0.1 to 0.5 [Mpa] for the plane electrode system with a needle-shaped protrusion. The curvature radius of the needle protrusion is 0.5[mm]. Also, the growth process of the predischarge are simultaneously observed. As a result, it is found that the breakdown mechanism and predischarge phenomena are closely associated with the polarity and waveforms of the testing voltage.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.334-337
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• 1997

This paper describes dielectric characteristics of SF$_{6}$ gas stressed by the non-oscillating and oscillating impulse voltages in inhomogeneous fields disturbed by metallic protrusion. The breakdown voltage-time (V-t) characteristics and breakdown voltage-gas pressure (V-p) characteristics and their characteristics are statistically investigated with positive and negative very fast transient overvoltages. The experiments were carried out using a needle-to-plane gap geometry in the gas pressure ranges from 0.1 to 0.5 MPa. The gap separation gas 22 mm, and the needle-shaped protrusions were made of stainless steel 10 mm in length and 1.0 mm in diameter.r.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.644-646
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• 2005

The air clearance of the transmission tower is determined by the switching overvoltage of the system, and the insulator length is determined by contamination design. This paper described the switching overvoltage analysis result of 500 kV system and air clearance design. The overvoltage include fault initiation, fault clearing, closing and reclosing overvoltages. We illustrated the contamination design example, air clearance design of a tower considering swing angle of the conductor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.647-649
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• 2005

가공배전계통의 주상변압기에는 직격뢰나 유도뢰에 의해 고압측이나 저압측으로부터 뇌과전압이 침입할 수 있고. 이러한 경우 침입단은 물론, 상대단에도 과전압이 나타날 수 있어, 주상변압기 자체와 고압 및 저압계통에 영향을 미치게 되므로, 주상변압기의 뇌과전압 전달특성을 파악하는 것은 절연설계와 절연협조에 있어 매우 중요한 자료가 된다. 본 논문에서는 실제 선로와 같은 구성과 규모의 실증 배전선로에서, 주상변압기에 임펄스전압이 침입한 경우의 변압기 양단에 나타나는 과전압에 패한 실증결과의 예를 소개하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 춘계종합학술대회
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• pp.480-483
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• 2000

We developed a home electric panel board with surge protection device to protect home electric appliances from transient overvoltages and electromagnetic(EM) noise. In this paper, electrical characteristics of the home electric panel board are described. From the performance test using a combination surge generator standardized in IEC 610004-5, it is confirmed that the proposed home panel board has an excellent surge protection performance. Also, EM noise reduction characteristics of the panel board in ranges from 150 kHz to 30 MHz is estimated by using a network analyser, and the results showed that the panel board has an over 20 45 noise reduction performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.443-446
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• 1989

154kV insulator strings are frequently damaged by lightning strokes, overvoltage and contamination. And this insulator damage inflicts a loss on the power company. The purpose of this paper is to develop the arcing horn as a protective device of 154kV insulator strings against lightning flashover and overvoltages. So We have developed the arcing horn which is suitable for 154kV transmission line and estimated the performance of arcing horn by high current arcs and high voltage tests.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.216-221
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• 2000

This paper describes the analysis results on the PT ferroresonance at 154 kV GIS (gas Insulated substation by EMTP(Electro- magnetic Transient Program). We had simulated the PT ferroresonance between a potential transformer(PT) and an open circuit breaker's grading capacitance. The ferroresonance leads to very large power frequency overvoltages on PT bus and subsequent insulation failure. The large power can be supplied to the PT by the high voltage on the opened circuit due to the grading capacitance and equivalent capacitance of the buses during the ferroresonance. The damping circuit connected on the secondary winding were considered in the model. The actual countermeasure include a saturable inductor and a resistor series-mounted, but the 2 ohms of damping resistance was used in the computationl model.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 춘계학술대회 논문집
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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.

• Journal of Electrochemical Science and Technology
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• 제11권1호
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• pp.26-32
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• 2020

In this study, the side reactions that greatly affect the coulombic efficiency of a zinc-air secondary battery are quantitatively analyzed on the basis of the charging-discharging characteristics, open circuit self-discharge characteristics, and a series of calculations. In particular, the charge amounts consumed by water electrolysis and self-discharge during charging process are separately determined so that the charging efficiency (the amount of charge used in actual charging with respect to the applied charge amount) can be estimated, which would enable systematic understanding of the cause of coulombic efficiency degradation. Using two cells with different charging overvoltages, the validity of the proposed method can be assessed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1822-1824
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• 1996

Damage and upset of control and communication equipment due to transient overvoltages which occur due primarily to internal switching surge and external lightning surge are an important problems in electromagnetic compatibility(EMC). In this paper, we analyzed operation characteristic of metal oxide varistor widely used low voltage AC line using the electromagnetic transients program(EMTP) and compare it with experimental results and also, we modeled combination generator producing $1.2/50{\mu}s$ open circuit voltage and $8/20{\mu}s$ short circuit current as a source which is critical in calculating operation characteristic. Simulation results showed that most of Transient energy consumes at MOV located in service entrance side than load side, and it showed similar to experimental results. Therefore, entrance side MOV should be selected more energy capacity than that of load side MOV.