• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.9
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• pp.395-399
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• 2003

In this paper, physical phenomena which are related to the high temperature and high pressure arc plasma generated during the fault current interruption by SF6 gas circuit breakers are reviewed. In particular, in order to analyze nozzle ablation induced by the heats transferred to the surface of the poly-tetrafluoroethylene(PTFE) nozzle through arc radiation, a governing equation for the calculation of PTFE concentration is added to the governing equations for SF6 arc Plasma analysis. The proposed method is applied to the steady state analysis of $SF_6$ arc plasma generated by direct current taking account of the nozzle ablation and the results are presented.

• ETRI Journal
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• v.21 no.3
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• pp.16-21
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• 1999

After etching Al-Cu alloy films using SiCl4/Cl_2/He/CHF3 mixed gas plasma, the corrosion phenomenon at the grain boundary of the etched surface and a passivation layer on the etched surface with an SF6 plasma treatment subsequent to the etching were studied. In Al-Cu alloy system, corrosion occurs rapidly on the etched surface by residual chlorine atoms, and it occurs dominantly at the grain boundaries rather than the crystalline surfaces. To prevent corrosion, the SF6 gas plasma treatment subsequent to etching was carried out. The passivation layer is composed of fluorine-related compounds on the etched Al-Cu surface after the SF6 treatment, and it suppresses effectively corrosion on the surface as the SF6 treatment pressure increases. Corrosion could be suppressed successfully with the SF6 treatment at a total pressure of 300 mTorr. To investigate the reason why corrosion could be suppressed with the SF6 treatment, behaviors of chlorine and fluorine were studied by various analysis techniques. It was also found that the residual chlorine incorporated at the grain boundary of the etched surface accelerated corrosion and could not be removed after the SF6 plasma treatment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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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.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.221-223
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• 2007

산업현장에서 많이 사용되고 있는 전력기기에 결함이 발생하면 치명적인 사고로 진전되어 경제적, 인적 손실이 발생될 수 있다. 본 논문은 현재 대전력기기에서 많이 사용되는 $SF_6$ 절연가스의 압력 변화에 따른 부분방전을 모의하고, UHF법을 이용한 모의 GIS 내부 부분방전 신호 측정 및 접지 전류를 측정하여 부분방전 시 방사되는 방사전자파의 스펙트럼 특성과 접지 전류 파형 특성을 분석하여, 챔버 내의 압력 변화가 $SF_6$ 가스 부분방전에 미치는 영향을 측정하였다. 이러한 연구는 현장 GIS 및 $SF_6$ 가스 절연 전력설비에서 내부 압력 변화가 원인이 되어 발생되는 절연파괴 사고의 방지에 중요한 역할을 할 것으로 사료된다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.9
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• pp.18-24
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• 2007

When faults occur in the power equipment that is used a great deal in industrial sites, it may lead to fatal accidents that cause losses both economically and in manpower. In this paper, the effect of particle impact on the partial discharge of $SF_6$ gas was measured by simulating a partial discharge following the type of fault found in the GIS using $SF_6$ insulating gas as the insulating material. A spectrum analysis was performed on the radiate electromagnetic waves emitted upon partial discharge by using the UHF insulation diagnosis method. This subject of this study is insulation diagnosis by the measurement of radiate electromagnetic waves when particles exist in the GIS and power equipment insulated with $SF_6$ gas.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.155-158
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• 2005

산업현장에서 많이 사용되고 있는 전력기기에 결함이 발생하면 치명적인 사고로 진전되어 경제적, 인적 손실이 발생될 수가 있다. 본 논문은 GIS에 사용되는 절연가스인 $SF_6$의 압력 변화에 따른 부분 방전을 모의하고, 발생되는 부분방전 신호를 절연 진단 방법 중 하나인 UHF법을 이용하여 부분방전 시 방사되는 방사전자파의 스펙트럼을 분석해 금속이물질이 $SF_6$가스 부분방전에 미치는 영향을 측정하였다. 이러한 연구는 현장 GIS 및 $SF_6$ 가스절연 전력설비에서 내부압력 변화 시 금속이물질에 의해 발생되는 절연파괴 사고의 방지에 중요한 역할을 할 것으로 사료된다.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1111-1113
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• 1999

This paper represents the characteristic analysis for the etching in $SF_6$ plasma and the plasma itself, based on the specific knowledges on the discharge mechanism of $SF_6$ plasma which is widely used for the applications of dry etching, using Radio Frequency Inductively Coupled Plasma (RFICP) by measuring electron density, electron temperature then observing their relationship to find the effect of discharge mechanism of $SF_6$ plasma to the etching in contrast to the existing method of finding optimal discharge condition by heuristic.

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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• pp.264-269
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• 2010

This paper presents the analysis of the dielectric characteristics of a hot $SF_6$ gas in a gas circuit breaker. Hot gas flow is analyzed using the FVFLIC method considering the moving boundary, material properties of real $SF_6$ gas, and arc plasma. In the arc model, the re-absorption of the emitted radiation is approximated with the boundary source layer where the re-absorbed radiation energy is input as an energy source term in the energy conservation equation. The breakdown criterion of a hot gas is predicted using the critical electric field as a function of temperature and pressure. To validate the simulation method, breakdown voltage for a 145kV 40kA circuit breaker was measured for various conditions. Consistent results between the simulation and experiment were confirmed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.12
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• pp.935-938
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• 2011

The etching characteristics of ZnO and etch selectivities of ZnO to $SiO_2$ in $SF_6$/Ar plasma were investigated using Inductively-coupled-plasma (ICP). The maximum etch rates of ZnO were 6.5 nm/min at $SF_6$(50%)/Ar(50%), Source power (700 W), Bias power (250 W), Working pressure(8 mTorr). The etch rate of ZnO showed a non-monotonic behavior with increasing from 0% to 50% Ar fraction in $SF_6$/ Ar plasma. The plasma diagnostic were characterized using Optical Emission Spectroscopy (OES) analysis measurements.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1485-1490
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• 2014

$SF_6$ gas has been used for power transformers or gas insulated switchgears, because it has the superior insulation property and the stable structure chemically. It has been, however, one of global warming gases and required to reduce the its amount. Some papers have reported that its amount could be reduced by mixing with other gases, such as $N_2$, $CF_4$, $CO_2$ and $C_4F_8$ and their mixture gases would cause the synergy effect. In this paper, we investigated the characteristics of DC plasmas on $SF_6$ mixture gases with $N_2$ at atmospheric pressure. $N_2$ gas is one of cheap gases and has been reported to show the synergy effect with mixing $SF_6$ gas, even though $N_2$ plasmas have electron-positive characteristics. 38 kinds of $SF_6/N_2$ plasma particles, which consisted of an electron, two positive ions, five negative ions, 30 excitation and vibration particles, were considered in a one dimensional fluid simulation model with capacitively coupled plasma chamber. The results showed that the joule heating of $SF_6/N_2$ plasmas was mainly caused by positive ions, on the other hand electrons acted on holding the $SF_6/N_2$ plasmas stably. The joule heating was strongly generated near the electrodes, which caused the increase of neutral gas temperature within the chamber. The more $N_2$ mixed-ratio increased, the less joule heating was. And the power consumptions by electron and positive ions increased with the increase of $N_2$ mixed-ratio.