• Title, Summary, Keyword: Mixture gases

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Lightning Impulse Breakdown Characteristics of SF6-based Mixture Gases (SF6계 혼합가스의 뇌임펄스 절연파괴특성)

  • Seo, Ho-Joon;Rhie, Dong-Hee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.7
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    • pp.675-681
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    • 2005
  • $SF_6$ is widely used as gas insulation medium because of having excellent dielectric and arc-quenching properties. However the use of it is getting to be suppressed from the viewpoint of mitigating global warming. For the development of environmentally-benign electric power equipment and system, novel gases or mixture gases are strongly required as the substitute of $SF_6$ gas. In this study the authors constructed an experimental system to investigate insulation properties of the mixed gases composed of negative $gas(SF_6)$ and electron deceleration gases$(N_2\;and\;CO_2)$. Breakdown and prebreakdown characteristics of $SF_6/N_2/CO_2$ mixture gases were investigated using the above mentioned system for different rates and gas pressures.

The Analysis of Insulation Properties with Electron Collision Processes on SF6 Mixture Gases (전자충돌과정을 통한 SF6 혼합기체의 절연특성 분석)

  • So, Soon-Youl
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.2
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    • pp.197-201
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    • 2010
  • $SF_6$ gas would be used in power transformer, GIS (Gas insulated switchgear) and so on because of its electrically superior insulation and chemically stable structure. Recently, the reduction of $SF_6$ is required to avoid global warming and the researches on the dilution of $SF_6$ with other gases have been carried out. $SF_6$ mixture gases with $N_2$ and $C_xF_y$ have drawn attention to the synergy effect. However, in order to understand the mechanism of the synergy effect, it is important to analyze and evaluate properties of mixture gases quantitatively. In this paper, we investigated the mechanism of synergy effect from electron collision processes and electron energy distribution by solving Boltzmann equation with propagator method. Three kinds of gases for dilution of $SF_6$ ($SF_6/N_2$, $SF_6/CF$4 and $SF_6/C_4F_8$) are considered in this simulation. On the properties of $SF_6/N_2$ mixture gas, the variation of reduced electric field was shown highly within 0%~40% mixtures of $SF_6$. And the more low-level electron energy has been distributed, the higher insulation capability has appeared.

A study of the Insulation Characteristic in $SF_6-N_2$ Mixture Gases ($SF_6-N_2$ 혼합기체의 절연특성에 관한 연구)

  • Ha, Sung-Chul;Song, Byoung-Doo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.613-616
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    • 2001
  • This SF6 gas is widely used in industrial of insulation field. In this paper, N2 is mixed to improve pure SF6 gas characteristics. Electron transport coefficients in SF6-N2 mixture gases are simulated in range of E/N values from 70 to 400 [Td] at 300K and 1 Torr by using Boltzmann equation method. The results of this method, which are like electron drift velocity, ionization coefficient, attachment coefficient, effective ionization coefficient, and critical EIN, can be important data to present characteristic of gas for insulation. Specially critical E/N is a data to evaluate insulation strength of a gas and is presented in this paper for various mixture ratios of SF6-N2 mixture gases.?⨀␍?܀㘱〮㜳㬓M敤楣楮攠慮搠桥污瑨

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A study of the Insulation Characteristic in $SF_{6}$-$N_2$ Mixture Gases ($SF_{6}$-$N_2$ 혼합기체의 절연특성에 관한 연구)

  • 하성철;송병두
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.613-616
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    • 2001
  • This $SF_{6}$ gas is widely used in industrial of insulation field. In this paper, $N_2$ is mixed to improve pure $SF_{6}$ gas characteristics. Electron transport coefficients in $SF_{6}$-$N_2$ mixture gases are simulated in range of E/N values from 70 to 400 [Td] at 300K and 1 Torr by using Boltzmann equation method. The results of this method, which are like electron drift velocity, ionization coefficient, attachment coefficient, effective ionization coefficient, and critical E/N, can be important data to present characteristic of gas for insulation. Specially critical E/N is a data to evaluate insulation strength of a gas and is presented in this paper for various mixture ratios of $SF_{6}$-$N_2$ mixture gases.

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Ionization and Attachment Coefficients in Mixtures of $SF_6$ and $N_2$ ($SF_6-N_2$ 혼합기체(混合氣體)의 전리(電離) 및 부착계수(附着係數))

  • Kim, Sang-Nam
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.1
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    • pp.44-47
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    • 2009
  • This paper describes the information for quantitative simulation of weakly ionized plasma. We must grasp the meaning of the plasma state condition to utilize engineering application and to understand materials of plasma state. $SF_6$ gas is widely used in industrial of insulation field. In this paper, $N_2$ is mixed to improve pure $SF_6$ gas characteristics. Electron transport coefficients in $SF_6-N_2$ mixture gases are simulated in range of E/N values from 70 to 400 [Td] at 300K and 1 Torr by using Boltzmann equation method. The results of this method. which are ionization coefficient, attachment coefficient, effective ionization coefficient, and critical E/N, can be important data to present characteristic of gas for insulation. Specially critical E/N is a data to evaluate insulation strength of a gas and is presented in this paper for various mixture ratios of $SF_6-N_2$ mixture gases.

The Analysis of DC Plasmas Characteristics on SFSF6 and N2 Mixture Gases (SF6/N2 혼합기체의 DC 플라즈마 특성 분석)

  • So, Soon-Youl
    • 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.

Analysis of Insulating Characteristics of Cl2-He Mixture Gases in Gas Discharges

  • Tuan, Do Anh
    • Journal of Electrical Engineering and Technology
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    • v.10 no.4
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    • pp.1734-1737
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    • 2015
  • Insulating characteristics of Cl2-He mixture gases in gas discharges were analysed to evaluate ability of these gases for using in medium voltage and many industries. These are electron transport coefficients, which are the electron drift velocity, density-normalized longitudinal diffusion coefficient, and density-normalized effective ionization coefficient, in Cl2-He mixtures. A two-term approximation of the Boltzmann equation was used to calculate the electron transport coefficients for the first time over a wide range of E/N (ratio of the electric field E to the neutral number density N). The limiting field strength values of E/N, (E/N)lim, for these binary gas mixtures were also derived and compared with those of the pure SF6 gas.

Electrical and Optical Properties of Microwave Discharged Lamp (마이크로파 방전램프의 전기적/광학적 특성)

  • Lee, Jong-Chan;Hwang, Myung-Keun;Bae, Young-Jin;Her, Hyun-Soo;Park, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.492-494
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    • 2002
  • The fundamental principles of the operation of microwave discharges that are used to convert microwave energy to broad spectrum visual light are known. In this paper, emission dependance of microwave discharges in mixture content of sulfur with noble gases was studied. It is shown that the excitation of this gaseous mixture is carried out in two phases: (1) ionization of noble gas atoms by a microwave field and (2) the consequent maintenance of slightly ionized nonequilibrium plasma by the field. These two processes have essentially various thresholds for the microwave pump. The purpose of this work is to investigate spectral properties of the high frequency discharges in a mixture sulfur vapors with noble gases.

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A Hierarchical Clustering Method Based on SVM for Real-time Gas Mixture Classification

  • Kim, Guk-Hee;Kim, Young-Wung;Lee, Sang-Jin;Jeon, Gi-Joon
    • Journal of the Korean Institute of Intelligent Systems
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    • v.20 no.5
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    • pp.716-721
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    • 2010
  • In this work we address the use of support vector machine (SVM) in the multi-class gas classification system. The objective is to classify single gases and their mixture with a semiconductor-type electronic nose. The SVM has some typical multi-class classification models; One vs. One (OVO) and One vs. All (OVA). However, studies on those models show weaknesses on calculation time, decision time and the reject region. We propose a hierarchical clustering method (HCM) based on the SVM for real-time gas mixture classification. Experimental results show that the proposed method has better performance than the typical multi-class systems based on the SVM, and that the proposed method can classify single gases and their mixture easily and fast in the embedded system compared with BP-MLP and Fuzzy ARTMAP.

A Study on The Ignition Limit of Flammable Gases by Discharge Spark of Resistive Circuit (저항회로의 개폐불꽃에 의한 폭발성 가스의 점화한계에 관한 연구)

  • Lee Chun-Ha
    • Journal of the Korean Institute of Gas
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    • v.1 no.1
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    • pp.106-112
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    • 1997
  • This study measured the ignition limits of methane-air, propane-air, ethylene-air, and hydrogen-air mixture gases by discharge spark of D.C. power resistive circuit. The used experimental device is the IEC type spark ignition test apparatus, it consists of explosion chamber and supply -exhaust system of mixture gas. Mixture gases (methane-air, propane-air, ethylene-air, and hydrogen-air) were put into explosion chamber of IEC type spark ignition test apparatus, then it was confirmed whether ignition was made by 3,200 times of discharge spark between tungsten electrode and cadmium electrode. The ignition limits were found by increasing or decreasing the value of current. For the exact experiment, the ignition sensitivity was calibrated before and after the experiment in each condition. The ignition limits were found by changing the value of concentration of each gas-air mixture in D.C. 24 [V] resistive circuit. As the result of experiment, it was found that the minimum ignition limit currents exist at the value of methane-air 8.3 [$Vol\%$], propane-air 5.25[$Vol\%$], ethylene-air 7.8 [$Vol\%$], and hydrogen-air 21[$Vol\%$] mixture gases. For each the minimum ignition concentration of gases, the relationships between voltage and minimum ignition current were found. The results are as follows. - The minimum ignition limits are decreasing in the order of methane, propane, ethylene, and hydrogen. - The value of ignition current is inversely proportional to the value of source voltage. - The minimum ignition limit currents increase sharply at more than 2 [A]. The reason is caused by overheating the electrode.

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