• 조명전기설비학회논문지
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• 제25권12호
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• pp.74-81
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• 2011

A computational approach was developed to understand about the arc quenching process in a gas circuit breaker(GCB). This approach is a program to analyze the gas flow in the breaker. The arc is processed at the same time. The program was used the so-called FLIC method for gas analysis techniques. It was referenced that the arc is interpreted the 'a Simplified Enthalpy Flow Arc Model'. In order to validate about the results of the program, a Auto Puffer GCB was chosen as the test subject. Because, the breaker is the one that arc current is interrupted by using the arc heating. And also, the current interrupting capability can be obtained only owing to the positive utilization(auto puffer) of the clogging phenomenon, without other puffer actions. In this paper, it has been realized that the entire arc quenching process is computerized, which is based on the self-flow current interruption by the auto puffer action. This program, which was verified through experiments, produced good results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1677-1681
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• 2002

A computational approach of the arc quenching process in GCB was developed. it is capable to calculates the thermodynamic quantities of the gas as a function of time taking into account of all spaces concerned with the arc quenching. Basically using so-called FLIC method, this program adoptes 'Simplified Enthalpy Arc Model', which is somewhat modified. And, to examine whether our works were done properly, it was simulated the whole process of the arc quenching that is based on self-flow generation phenomena/current interruption in a thermal expansion type circuit breaker. This program was verified by experiments, both showed fairly good agreement.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.708-710
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• 2001

In this paper, back commutation phenomena for iron chute chamber in AC low testing. For this experimental we used high speed camera and carried out with same prospective currents up to 10kA RMS. Hybrid arc quenching chambers which are composed with iron plate and insulating materials tested for reducing back commutation phenomena in interrupting process. It is shows that hybrid chambers which are various narrow slot path width reduces back commutation. As a result, a new type arc quenching chamber is to force the arc rapidly into a narrow insulating slot with iron plate. By this means the arc is lengthened and squeezed between insulating walls. Using this model, the behavior of the arc squeezed in the hybrid chamber and characteristics of arc voltage are also investigated.

• 한국해양공학회지
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• 제1권2호
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• pp.67-73
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• 1987

The feasibility for a practical use of underwater wet arc welding process is experimentally investigated by using low hydrogen and high oxide type electrodes and TMCP steel plates. Main results are summarized as follows: 1)The absorption speed of the coated low hydrogen and high titanium oxide type eletrodes becomes constant after about 30 minutes in water, and more steeping time in water does not influnce welding arc behavior. 2) By bead appearance and X-ray inspection, the high titanium oxide type electrode is better than the low hydrogen type in underwater arc welding process. 3) The mechanical properties of underwater wet arc welds depend upon welding conditions more than those of in-air welds, and the optimum welding condition can be obtained. 4) Because of quenching effect by rapid cooling rate in underwater wet welding, the maximum hardness of HAZ is increased relatively higher in underwater wet welding, process.

• 한국세라믹학회지
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• 제29권9호
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• pp.681-688
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• 1992

Ultrafine Si3N4 and Si3N4+SiC mixed powders were synthesized through thermal plasma chemical vapor deposition(CVD) using a hybrid plasma, which was characterized by the supersposition of a radio-frequency plasma and arc jet. The reactant SiCl4 was injected into an arc jet and completely decomposed in a hybrid plasma, and the second reactant CH4 and/or NH3 mixed with H2 were injected into the tail flame through double stage ring slits. In the case of ultrafine Si3N4 powder synthesis, reaction efficiency increased significantly by double stage injection compared to single stage one, although crystallizing behaviors depended upon injection speed of reactive quenching gas (NH3+N2) and injection method. For the preparation of Si2N4+SiC mixed powders, N/C composition ratio could be controlled by regulating the injection speed of NH3 and/or CH4 reactant and H2 quenching gas mixtures as well as by adjusting the reaction space.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.167-169
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• 1998

Recently $SF_6$ gas circuit breakers utilizing the thermal-expansion principle are increasingly used in distribution power system. Active researches and developments have been conducted to reduce the size and weight, and to improve the interrupting performance of the circuit breakers. It was first developed a programme which could show the hot gas flowing into the thermal-expansion arc chamber. This programme, using so-called FLIC method basically, adopted 'Simplified Enthalpy Arc Model' which was somewhat modified to estimate the arc quenching process. The computation by it was compared with the measured results of the pressure rise in the chamber, and both showed fairly good agreement.

• 한국진공학회지
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• 제12권1호
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• pp.25-34
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• 2003

탄소 원자 간의 interaction potential로서 Tersoff에 의해 제안된 반 경험적인 potential을 이용하여 고경질 탄소박막의 합성 거동을 전산 모사하였다. 고에너지의 탄소익사를 diamond (100) 표면에 충돌시켜 고밀도의 비정질 탄소박막을 만들 수 있었으며, 전산모사에 의해 합성된 탄소 박막의 물성과 Shin 등이 발표한 filtered cathodic arc 공정에 의해 합성된 탄소의 물성을 비교하였다. ta-C 합성 실험에서 관찰된 바와 같이 최적의 에너지 영역에서 다이아몬드에 가장 유사한 물성의 필름이 합성되었으며, 이때의 입사원자 에너지인 50 eV 는 실험적으로 최적의 필름이 얻어지는 조건에서의 탄소이온 에너지와 유사하였다. 전산모사에 의해 합성된 박막은 비정질이었으며, 다이아몬드 lattice에 해당하는 short range order를 가지긴 있었다. 그러나, 최적의 에너지 조건에서는 2.1 $\AA$의 거리의 준안정 site에 탄소들이 많이 존재하는 것을 알 수 있었는데, 이는 필름 표면의 국부적 급냉효과가 최대가 되는 조건과 일치하였다. 이러한 결과는 다이아몬드상 카본필름의 합성에 있어서, 고 에너지의 탄소인자가 충돌하면서 발생하는 국소적인 열에너지의 증가가 가장 빨리 제거되는 조건에서 최적의 물성을 가지는 경질탄소 필름이 형성되는 것을 보여주고 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2494-2499
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• 2007

Self-blast circuit breakers utilize the energy dissipated by the arc itself to create the required conditions for arc quenching during the current zero. The high-current simulation provides information about the mixing process of the hot PTFE cloud with $SF_6$ gas which is difficult to access for measurement. But it is also hard to simulate flow phenomenon because the flow in interrupter with high current, $SF_6$-PTFE mixture vapor and complex physical behavior including radiation, calculation of electric field. Using a commercial computational fluid dynamics(CFD) package, the conservation equation for the gas and temperature, velocity and electric fields within breaker can be solved. Results show good agreement between the predicted and measured pressure rise in the thermal chamber.

• 전기학회논문지
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• 제57권12호
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• pp.2199-2201
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• 2008

Sulfur hexafluoride($SF_6$) is a gaseous dielectric used in high voltage electrical equipment such as an insultor or arc quenching medium in the transmission and distribution of electricity. however, $SF_6$ is one of the greenhouse gases(GHG) with a global warming potential that is 23,900 times greater than that of carbon dioxide($CO_2$). for this reason, $SF_6$ emissions in electric equipment shall be controlled to reduce GHG and improve cost-effective use of $SF_6$ for economical benefits. Until recently there has not been any investigation on $SF_6$ emission characteristics and inventory in Korea. To understand emission characteristics during the use-phase, the scope of this study was limited to the following closed pressure system equipment from 10 substations in Korea. This study highlights (1) the investigation of sampling/analysis methodology for $SF_6$ emissions in high voltage equipment, (2) the estimation of $SF_6$ emissions in the use-phase, and (3) the comparison between the emission ratio and the mass-balance applied to inventory study. According to this study, the majority of emissions were related to electric equipment nameplates and the rest of the emissions were related to the handling of $SF_6$ during operations. from this result, emission ratios estimated from this study were similar; GIS was 14% and GCB was 13%, as maintenance process conditions were the same as manual process conditions for both equipment.

• 한국수소및신에너지학회논문집
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• 제9권1호
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• pp.16-24
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• 1998

최근 Ni-MH 전지의 고성능화를 위해 방전용량이 높은 Zr기 $AB_2$ 형의 수소 흡장 합금이 주목받고 있다. 본 연구에서는 이 중에서 $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ 합금을 선택하여 합금의 열처리 그리고, Mn 대신 Mo의 부분치환이 전극의 특성에 미치는 영향을 조사하였다. 합금은 먼저 아크 용해로를 사용하여 제작하였으며, 이 합금 중 일부를 $1,100^{\circ}C$에서 가열 후 각각 서냉과 급냉 처리를 행하였다. 이 세 가지 종류의 합금들을 이용하여 활성화 거동, 고율 방전 특성, 자기 방전 특성 등의 전극특성을 평가하였다. 그 결과 합금은 열처리에 의해서 방전용량이 감소하고 고율 방전율 또한 감소하였다. 그러나, 전기 화학적으로 구한 압력-조성 등온곡선의 평탄구역의 기울기를 감소시켰다. 또한 $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ 합금의 Mn을 Mo으로 부분 치환함에 의해서 방전용량의 감소 없이 자기방전특성을 크게 개선할 수 있었다.