• 조명전기설비학회논문지
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• 제27권4호
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• pp.73-80
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• 2013

Breakdown characteristics of air in the vertical arrangement of line conductor and plane electrode in case of combustion flame on the plane electrode are examined by the application of AC. and DC voltages to the gap. In order to investigate the effect of paraffin flame on the breakdown characteristics of air, flashover voltages are measured according to the variation of the gap length and the horizontal distance between the flame and the line conductor. As the result of the experiment, flashover voltages are substantially lowered down to 29.8% in case of the AC voltage, and 16.1% in case of the negative DC voltage, when in the presence of the flame. from 100% when in the absence of flame. Flashover voltages of air in the range of smaller than 3㎝ at the horizontal distance are increased in the proportion of the gap length and the horizontal distance in case of both AC and negative DC voltages. But before the flashover occurs, the flame is extinguished by such corona wind that is produced from the line conductor when the gap length and the horizontal distance reach to a certain degree. The effect of relative air density and the phenomenon of thermal ionization are analysed as the reduction factors of flashover voltages, due to high temperature of the flame.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1469-1471
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• 1996

In this paper, We intended to evaluate the characteristics of XLPE/EPDM interface which exists in the cable joint. The fault of practical cable was mainly occurred in this interface. Thus we looked into the electrical characteristics through the conduction current and the breakdown test. Through the experiment, we obtained the result that the conduction current in this interface flowed less than other dielectric materials, that the breakdown strength was higher and that the pressure dependance of the breakdown strength was higher.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1181-1187
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• 2015

Sulfur hexafluoride (SF₆) gas is used widely in electric power equipment such as Gas Insulated Switchgear (GIS), Gas Insulation transmission Line (GIL), and Gas Circuit Breaker (GCB). But applications of SF₆ should be restricted because SF6 gas is one of the greenhouse effect gases. To reduce use of SF₆ gas, a study on eco-friendly alternative insulation medium is needed. In this paper, we investigated lightning impulse (LI) breakdown of dry-air which is attracting attention as an ecofriendly alternative gas and the LI breakdown of hybrid insulation combined with dry-air and solid insulation (Room-Temperature Vulcanizing Silicone Rubber-RTV SIR) and dry-air in inhomogeneous fields according to gap distance and pressure. The experiment results showed that the LI breakdown strength of hybrid insulation system was higher than that of dry-air insulation system. It was verified that the development of technology related to eco-friendly power apparatus compact such GIS, GCB and GIL can be used as basic research data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1669-1671
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• 1997

Liquid nitrogen has many adventages. It is cheaper than other cooling medium. It is easy to obtain high purity. It's utilized with easy. In future, liquid nitrogen is able to be accepted cooling medium for the superconducting and cryogenic applicated equipments. Cryogenic liquid may be atmospheric pressure state because thermoinsulation is ineffective, airtight decreasing by long time using and bubble occured by flowing current. If it is to be atmospheric pressure state, the electrical insulation strength is dropped and processed partial discharge, finally breakdown. Processing of breakdown has anticipated by measuring radiated-electromagnetic wave which is happened in time of breakdown. There is a measurement of radiated electromagnetic wave as a method that proceeding breakdown is anticipated. In this paper, radiated electromagnetic wave was measured in arc discharge by above conditions as a basic experiment.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.462-463
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• 2007

SF6 widely used as insulating gas is rising as the environment problem. For decreasing this greenhouse gas, electrical breakdown characteristics of composite insulation composed of epoxy resins with N2, air are studied in non-uniform field. The gap of needle to plane was 3mm, 5mm. The pressure of air, nitrogen was varied within the range of 0.1~0.6MPa. The thickness of a needle is 1mm and the curvature radius of the end of needle is 100um. The diameter of a plane made of the stainless steel is 50mm. As a result of the experiment, the breakdown voltage is increased about 3 times when epoxy resins is composited. The thickness of epoxy resins filled opposite to electrode concentrated electric field weakly influences on breakdown voltage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1389-1390
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• 2007

SF6 gas used widely as insulating component is rising as the environment problem. Electrical breakdown characteristics of epoxy and dry-air composite insulation was investigated on thickness of epoxy and pressure of dry-air under non-uniform field. The gap of needle to plane was from 2mm to 5mm. The pressure of dry-air was varied within the range of $0.1{\sim}0.6$ MPa. The thickness of a needle was 1mm and the curvature radius of a needle end was 100um. The diameter of a plane made of the stainless steel was 50mm. As a result of the experiment, breakdown voltage was increased about 3 times when epoxy was used. The impact that the thickness of epoxy influences on breakdown voltage was poor. It needs suitable thickness computation because the insulating gap of the gas is short as epoxy thickness increases.

• 전기의세계
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• 제24권5호
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• pp.82-90
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• 1975

This study investigated the deterioration phenomena of the Polyethylene surface contaminated with organic(Saccharose) or inorganic(NaCl) matters through electrical and optical experiments. And also these experimental results relatively well coincided with which was treated by theoretical process. On the electrical experiment, relation between electric field intensity in corona discharge and time reached to the breakdown, and relation between total amount of charges discharged and increment of applied voltage were investigated. On the optical experiment, discharge time dependence of surface deterioration rate and process of surface deterioration in the X-ray diffraction pattern were investigated. It was concluded that chemical effects by the corona discharge deteriorated insulation characteristics of Polyethylene surface.

• 한국컴퓨터산업학회논문지
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• 제3권12호
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• pp.1747-1758
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• 2002

실리콘 젤의 경화조건에 따른 전기적 특성을 조사하기 위하여 절연파괴특성에 대한 실험을 실시하였다. 실험을 위해 온도 100[$^{\circ}C$], 125[$^{\circ}C$], 150[$^{\circ}C$], 160[$^{\circ}C$], 170[$^{\circ}C$], 180[$^{\circ}C$]에서 각각 30[Min], 1[H], 2[H]동안 경화된 여러 시료를 제작하였다. 절연파괴실험에서 사용된 전극의 재료는 순도 99.9[%]의 구리이며, 전극간 간격은 1~3[mm]로 하였고, 전극의 두께는 0.2[mm]이다. 실험결과 온도 170[$^{\circ}C$]에서 2[H] 경화된 시료의 전기적 특성이 가장 우수하였다.

• 전기의세계
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• 제22권4호
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• pp.30-34
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• 1973

The main purporse of this paper is to study on the influence of temperature effect on electrical-properties, i.e., dielectric breakdown voltage, dielectric constant and resitivity of homemade insulating oil containing antioxidant. Transformer oil manufactured in Korea is taken for a sample, and this sample is classified into seven samples in which antioxidant is contained and not contained, and antioxidant is divided into three kinds of amount: 0.3%, 0.5%, 0.8%. Changing the tempe5rature of the samples by oil bath, the electric properties measured from the samples are as follows: (1) the variation of either the dielectric breakdown voltage or the resistivity are considerably large, but the dielectric constants are almost unchanging. (2) In view of electrical characteristic, the deterioration rate of the samples containing antioxidant is somewhat lower than that of other samples. (3) Nearly the same value is shown in the dielectric-breakdown voltage of the samples, in which contained the different amount of antioxidant: 0.3%, 0.5%, 0.8%, but the decrease rate of resitivity is lowest, 0.3%, of all. As the result of the experiment, This study can suggest that 0.3% be the optimum amount of antioxidant which will be added transformer oil manufactured in Korea and is useful for the understanding about the electrical properties of transformer oil containing antioxidant.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.941-943
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• 1999

In this paper, the AC breakdown properties to investigate the electrical properties of gate oxide layer in MOSFET was studied. 5 inch arsenic epi-wafer is selected as an experimental specimen, the power MOSFET of a general MOS structure was made. In order to analyze the physical properties of the specimen, the SIMS(secondary ion mass spectroscopy) was used. As the experimental condition, the experiment al of the AC breakdown characteristics was performed when the thickness of gate oxide layer is $600[\AA]$ and $800[\AA]$, the resistivity is $1.2[\Omega{\cdot}cm]$, $1.5[\Omega{\cdot}cm]$ and $1.8[\Omega{\cdot}cm]$, and the diffusion time is 110[min] and 150[min] in temperature $30[^{\circ}C]{\sim}100[^{\circ}C]$. From the analysis result of the SIMS spectrum, it is confirmed that the dielectric strength is decreased by contribution of the impurities ad dition as increasing in thickness of the gate oxide layer in MOSFET.