• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.7
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• pp.41-46
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• 2010

With the improvement of industrial society, high quality electrical energy, simplification of operation and maintenance, and ensuring reliability are being required. Also we request an urgent change from $SF_6$ gas to an environment-friendly gas insulation material. In this paper, the experiments of breakdown characteristics by pressure and gap change of $N_2/O_2$ mixture gas through a GIS (Gas Insulated Switchgear) model were described. This paper reviews basic data of the surface discharge characteristics for Teflon resin in not only pure $N_2$, $N_2:O_2$ mixture gas as being focused on environmentally-friendly insulating gas, but also $SF_6$. Also, insulation characteristics by breakdown voltage and surface discharge voltage of $N_2:O_2$ mixture gas in the experimental chamber were studied.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.20-27
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• 2007

[ $SF_6$ ] gas for compacted power facilities has a important role as an insulation gas. It is very blown well that $SF_6$ gas has the superior characteristics as an insulation gas. For reliable operation of SF6-gas-based high and medium voltage equipment it is very important to keep the insulation ability within a safe range. And the experimental and measuring system were implemented. The test chamber designed to endure up to 3 atmospheric pressure. The analysis results of the experimental data shows that positive partial discharge can be detected by discharge current and UHF signal. Additionally it is shown the possibility that $CO_2$ gas sensor of semiconductor type can be detect the variation of $SF_6$ gas condition. The UHF sensor shows good feature to detect the variation of $SF_6$ gas condition for partial discharge and breakdown discharge.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1382-1384
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• 1995

In order to study the structure of RF glow discharge driven at 13.56MHz in argon, the discharge voltage, current and phase shift between them will be measured over a wide range of discharge parameters(gas pressure between 1mTorr and 50mTorr with discharge power between 20mW and 200W). In this paper, the dc glow discharge characteristics and plasma parameters of both FTS and CPMS systems are studied experimentally. It is found that for CPMS system discharge is stablized under wider ranges of magnetic field and pressure than for FTS system. The plasma density and electron temperature of the plasma for these two systems are in the range of $10^{10}{\sim}7{\times}10^{11}[cm^{-3}]$ and $3.5{\sim}6.5$[eV], respectively.

• KIEE International Transactions on Electrophysics and Applications
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• v.2C no.6
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• pp.297-303
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• 2002

We have developed an on-line ultrasonic detector to monitor partial discharge in an operating transformer. The ultrasonic sensor has 150[KHz] resonance frequency and contains a pre-amplifier with 60[㏈] gain. The on-line ultrasonic detector has 50~300[KHz] frequency band-pass filter to remove electrical and mechanical noises from the transformer. This detector has an ultrasonic signal discrimination algorithm which discriminates ultrasonic signals due to partial discharge in a transformer. A moving average method of ultrasonic signal number was employed to effectively monitor the increasing trend of the partial discharge. This paper describes an experience of partial discharge detection in a 154[㎸] operating transformer using an ultrasonic detector. With regards to gas analysis in oil, C2H2 gas was produced with a warning level in this transformer We detected ultrasonic signals on the transformer steel wall, and estimated the position of partial discharge. With further inspection, we found carbonized marks due to partial discharge on the supporting bolt which fastens the windings.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.3
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• pp.321-328
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• 1990

The effect of a small discharge on the A.C (60Hz) breakdown characteristics in SF6 gas has been studied. Various experiments were investigated while varying distance of the rod-plane electrode, the gas pressure, and the magnitude of the small discharge current. Also, the position of the discharge path was observed for the purpose of evident investigation. As the results of this study, authors clarified the shifting mechanism of the position of discharge path with the ratio Rn (E/N distribution at a certain higher tempera-ture due to the small discharge current to E/N distribution at room temperature, E:electric field strength, N:particle number density). Also, the reason for the reduction of the A.C. breakdown voltage was investigated in the presence of a small discharge current.

• Journal of the Korean Chemical Society
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• v.34 no.5
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• pp.396-403
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• 1990

We describe how to design and construct a LPCVD (Low Pressure Chemical Vapor Deposition) apparatus which can be applicable to the study of reaction mechanism in general CVD experiments. With this apparatus we have attempted to make diamond like carbon films on the p-type (111) Si wafer from (H$_2$ ＋ CH$_4$) gas mixtures. Two different methods have been tried to get products. (1)The experiment was carried out in the reactor with two different inlet gas tubes. One coated with phosphoric acid was used for supplying microwave discharged hydrogen gas stream, and methane has been passed through the other tube without the microwave discharge. In this method we got only amorphous carbon cluster products. (2) The gas mixture (H$_2$ ＋ CH$_4$) has been passed through the discharge tube with the Si wafer located in and/or near the microwave plasma. In this case diamond-like carbon products could be obtained.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1237-1240
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• 2005

The effects of various sustain waveforms on the discharge characteristics, such as discharge current waveform, IR waveform, luminance, luminous efficiency, power consumption, and static margin are investigated under high Xe (20%) gas mixture at 200 kHz. The four types of sustain waveforms, such as non-overlapped sustain waveform without auxiliary pulse, non-overlapped sustain waveform with auxiliary pulse, overlapped sustain waveform without auxiliary pulse, overlapped sustain waveform with auxiliary pulse, are examined intensively. As a result, the overlapped sustain waveform with auxiliary pulse shows the best discharge characteristics under high Xe (20%) gas mixture at 200 kHz.

• Electrical & Electronic Materials
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• v.8 no.6
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• pp.721-726
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• 1995

In this paper, reduction characteristics of NOx gas produced from diesel engine combustion is studied by using pulse corona discharge. Nox concentration of 1900ppm (NO 1870, NO$\sub$2/ 30 ppm, N$\sub$2/ balance gas) was controlled in a fixed quantity of 280ppm, using a flow meter. Reactors are composed of cylinder type. NOx reduction rate is investigated with discharge electrode diameter[0.5,1,3,4.phi.], reactor length [130,300mm], reactor materials[Copper, Poly Vinyl Chloride] and Input voltage[DC, AC, DC Pulse square voltage]. In the result, NOx reduction rate is the best of all in copper reactor, small electrode diameter[0.5.phi.], DC pulse voltage and long reactor[300mm]. Then Teduction rate of NOx is about 93%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.3
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• pp.265-272
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• 2000

In this paper the corona discharge in SF$_{6}$ gas used as insulating material in lots o high voltage equipment, is simulated by finite element method with Flux-Corrected Transport(FCT) method. By application of proposed method the negative corona discharge characteristics in needle to plane electrode is analyzed with time step. For the accuracy of analysis the secondary electron emission by photon and ion are also considered as well as the accuracy of analysis the secondary electron emission by photon and ion are also considered as well as townsend first ionization and electron attachment. The calculated results show that the electric field intensity between anode and ion group is decreased as times go-by according to field distortion by those space charge. Accordingly the electron density is decreased strongly by the attatchment effect of SF6 gas so that the corona discharge becomes extinguished abruptly.y.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.229-233
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• 2022

In this study, a gas-liquid hybrid atmospheric pressure plasma reactor of the dielectric barrier discharge method was fabricated and characterized. The solubility of copper oxide in the organic acid solution was increased when argon having a larger atomic weight than helium was used during plasma discharge. There was no significant effect of mixing organic acid solutions under plasma discharge treatment on the variation of copper oxide's solubility. As the applied voltage for plasma discharge and the concentration of the organic acid solution increased, the dissolution and removal power of the copper oxide layer increased. Solubility of copper oxide was more affected by the concentration in organic acid solution rather than the variation of plasma applied voltage. The usefulness of hybrid plasma reactor for the surface cleaning process was confirmed.