• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.300-303
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• 1991

Sulphur-hexafluoride has extensively been used as an insulating gas of electric power equipment in substation for its high dielectric strength, non-toixity and non-flammable properties. But it is very expensive and is liquidizable under the condition of low temperature and high pressure. And it is very sensible to the locally high electric field strength. To resolve these problems, we studied 50% FOV and V-t characteristics of $SF_6-N_2$ mixtures under positive and negative lightning impulses using a 25mm rod-plane gap. 50% FOV of $SF_6-N_2$ 50% mixture was about 85% of pure $SF_6$ and it was known that $SF_6-N_2$ mixtures can be used as an economic substitution insulating gas for $SF_6$.

• 전기학회논문지
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• 제61권4호
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• pp.601-605
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• 2012

The non-controlled closing of High-voltage SF6 gas circuit breaker can cause transient current and overvoltage in the field. The controlled closing technology is an effective way to reduce transient current and voltage, prevent equipment failures, and improve power quality. For the development of controlled closing, it is obviously necessary to determine the withstand voltage between arc contacts of High-voltage SF6 gas circuit breaker in making operation. This paper focuses on decrease of pressure and density of SF6 gas that can affect withstand voltage between arc contacts in making operation. The dielectric strength between arc contacts could be improved by minimizing the decrement of pressure and density of SF6 gas obtained by simulation and test and moreover the rate of decrease of dielectric strength (RDDS) of arc contacts could be foreseen.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.198-199
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• 2006

AC spark discharge voltage of SF6/C02and SF6/N2 containing various mixed rate in volume percent (1, 5 and 10%) of SF6 in non-uniform fields are investigated. The needle to plane electrode gap spacing was 5 and 10 mm, and the gas pressure was varied within the range of 0.1${\sim}$0.7 MPa. We have observed a N-characteristic typical for the electronegative gases even in gas mixtures of 1% SF6 with CO2 and N2 as buffer gases. Especially, the materials of the needle electrode affect the insulation properties of the gas mixtures drastically. On the contrary to the case of needle electrodes made by mild steel or high carbon steel, the N-characteristics are hardly perceived in the case of stainless steel needle in this experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.89-91
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• 1999

The performance of circuit interruption of $SF_6$ puffer cylinder type gas circuit breaker(GCB) has been evaluated from the results of electrical insulation strength which is depend on material property, such as $SF_6$ gas density in circuit breaker tank. In order to determine circuit breaker dimension in the safety criteria. electrical field analysis has been done by finite element method. Gas density of concerned area in the circuit breaker has been calculated. In order to predict small current break performance, Electrical field analysis result must be calculated based the results of density from cold flow dynamics. The proposed method has been carried out and evaluated for 362kV class high voltage GIS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1455_1456
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• 2009

$SF_6$ is the most commonly used insulating gas in electrical systems. But In these days $SF_6$ mixtures and alternative gas has been studied because of global warming. so although many studies have been carried out about binary gas mixtures with $SF_6$, few studies were presented about breakdown characteristics of $SF_6/CF_4$ mixtures. At present study the breakdown characteristics of $SF_6/CF_4$ mixtures in quasi-uniform field was performed. This experiments were carried out under AC voltages. The rod-rod electrode was used with 5 mm gap distance. The mixture of $SF_6/CF_4$ containing 20%,50%,70% of $SF_6$ were compared with pure $SF_6$ and $CF_4$ gas and gas pressure ranged from 0.1 to 0.5 MPa. The show that the breakdown voltages of gas were linearly increased according to the pressure in quasi-uniform field. For breakdown vlotage values of $(E/P)_{crit}$ are important. Because If values of (E/P) is a little more than $(E/P)_{crit}$, electrons rapidly increase and streamer discharge gernerates. Through this experiments values of $(E/P)_{crit}$ are found to vary with the ratio of $SF_6/CF_4$ mixture according to the following relationship. $V_b=(E/P)_{crit}{\cdot}p{\cdot}d$

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.711-711
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• 2009

Global warming has been widely recognized as a serious problem threatening the future of human beings. It is caused by the buildup in the atmosphere of greenhouse gases, such as carbon dioxide, methane, hydrofluorocarbons (HFCs), and sulfur hexafluoride (SF6). Particularly, SF6 has extremely high global warming potential compare to those of other global warming gases. One option for mitigating this greenhouse gas is the development of an effective process for capturing and separating these gases from anthropogenic sources. In general, gas hydrates can be formed under high pressure and low temperature. However, SF6 gas is known to form hydrate under relatively milder conditions. Therefore, technological and economical effects could be expected for the separation of SF6 gas from waste gas mixtures. In this study, we carried out morphological study for the SF6 hydrate crystals to understand its formation and growth mechanisms. The observations were made in high-pressure optical cell charged with liquid water and SF6 gas at constant pressure and temperature. Initially SF6 hydrate formed at the surface between gas and liquid regions, and then subsequent dendrite crystals grew at the wall above the gas/water interface. The visual observations of crystal nucleation, migration, growth and interference were reported. The detailed growth characteristics of SF6 hydrate crystals were discussed in this study.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.153-154
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• 2008

변전기기의 주요 절연매질인 절연유 및 $SF_6$ 가스에서 절연불량으로 부분방전이 발생할때 방사되는 전자기파 특성을 측정, 분석 하였다. 부분방전 발생기구로 부유전극을 제작하여 실험하였으며 부분 방전에 의한 전자기파 신호의 특성을 분석한 결과 변압기 주 절연물인 절연유에서 발생하는 부분방전신호가 크고 높은 주파수의 신호가 발생하였고, 가스절연개폐장치 주 절연물인 $SF_6$ 가스에서 발생하는 부분방전신호도 비교적 높은 주파수 신호가 발생하였다. 본 분석결과는 변전소 주요 설비인 변압기 및 가스절연개폐장치에서 발생가능한 절연이상을 진단하기 위한 전자기파를 이용한 부분방전 분석기술 개발에 응용할 예정이다.

• 조명전기설비학회논문지
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• 제12권1호
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• pp.3-11
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• 1998

스페이서 표면 파티클에 의한 오염의 영향은 SF6GIS의 절연내력을 현저히 감소시킨다. 이와 관련해서 우리는 평행평판전극 구성으로 SF6가스중에서 금속 및 비금속 파티클의 위치 및 형태를 변화시키면서 교류전압에서 섬락전압 특성과 파괴 기구에 대해서 연구했다. 주된 결과는 $\circled1$파티클 위치에 대한 섬락전압 감소의 영향은 갭중간에서 가장 적고 전극에서 미소간극 분리된 경우의 영향이 가장 커다. $\circled2$ 섬락전압 감소가 크게 되는 금속 파티클 일수록 FOV 포화 현상은 낮은 압력 영역으로 이동된다. $\circled3$0.6[mm]이하의 비금속 파타클은 섬락전압에 그의 영향을 미치지 않는다.

• 한국재료학회지
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• 제18권2호
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• pp.73-76
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• 2008

[ $SF_6$ ] gas has been widely used as an insulating, cleaning and covering gas due to its outstanding insulating feature and because of its inert properties. However, the global warming potential of $SF_6$ gas is extremely high relative to typical global warming gases such as $CO_2$, CFCs, and $CH_4$. For these reasons, it is necessary to separate and collect waste $SF_6$ gas. In this study, the effects of a surfactant (Tween) on the formation rate of $SF_6$ gas hydrates were investigated. The $SF_6$ gas hydrate formation rate increased with the addition of Tween and showed a nearly 6.5 times faster hydrate formation rate with an addition of 0.2 wt.% Tween compared to an addition of pure water. This is believed to be due to the increased solubility of $SF_6$ gas with the addition of the surfactant. It was also found that $SF_6$ gas hydrate in the surfactant solution showed two-stage hydrate formation rates with a formation rate that increased rapidly in the 2nd stage.

• 전기기술인
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• 통권131호
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• pp.26-29
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• 1993