• 한국지반환경공학회 논문집
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• 제22권12호
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• pp.59-63
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• 2021

본 연구는 대심도 조건의 고효율 그라우팅 기술개발을 위한 그라우트재 배합비를 제시한 것으로써 연구에 사용된 1종 보통 포틀랜드 시멘트(OPC)와 마이크로 시멘트(S8000-E)의 배합별 특성과 첨가제 효과를 점도 실험, 입경분석 실험, Gel-Time 실험, 일축압축강도 실험을 통해 확인하였다. 점도실험 결과 점도적인 측면에서 고려하였을 때 OPC가 유리하지만 입경 분석을 통한 암반 절리 간격 통과 고려 시 S8000-E가 적합하다는 것을 확인할 수 있었다. Gel-Time 실험 결과 OPC보다 S8000-E에서 효율적인 값을 나타내었으며 실리카퓸(SF) 적용 시에도 그라우트재로서 주입에는 문제가 없음을 확인하였다. 일축압축강도 시험결과 실리카퓸(SF) 함유량 증가에 따른 강도 증진 효과 및 양생시간에 따른 압축강도 변화를 확인하였으며 여러 가지 실험을 통해 산정된 최적의 배합비는 S8000-E, w/c=70%, 실리카퓸(SF)=6%, 7일 양생으로 대심도 조건의 고효율 그라우트재로서 주입에 가장 효과적인 것으로 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1548-1549
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• 2011

High voltage cryogenic insulation issues need to be addressed in order to promote the commercialization of high temperature superconducting (HTS) equipment. As a fundamental step in the development of the optimum bushings for HTS devices, the breakdown characteristics of liquid nitrogen mixed with liquefied insulating gases such as $N_2$, $SF_6$, and $CF_4$ have been investigated. In order to investigate the possibility of substituting $CF_4$ gas for $SF_6$ gas for the bushings of HTS electrical equipment, AC withstanding voltage tests have been performed. In this paper, finding the maximum electric field $E_{max}$ using utilization factor ${\eta}$. This result is applicable to developing the real scale HTS equipment of the design parameters.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.185-188
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• 2002

This paper describes the information for quantitative simulation of weakly ionized plasma. We should grasp the meaning of the plasma state condition to utilize engineering application and to understand materials of plasma state. In this paper, the drift velocity of electron in $SF_6+O_2$ mixture gas calculated for range E/N values l~900[Td] at the temperature is 300[$^{\circ}K$] and pressure is 1[Torr], using a set of electron collision cross sections determined by the authors and the values of drift velocity of electrons are obtained for TOF, PT, SST sampling method of Backward Prolongation by two term approximation Boltzmann equation method. It has also been used to predict swarm parameter using the values of cross section as input. The result of Boltzmann equation, the drift velocity of electrons, has been compared with pure $SF_6$, pure $O_2$ and mixture gas.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.30-32
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• 1995

The model interrupters of $SF_6$ gas electromagnetic contactor whose ratings are the voltage of 7.2kV and the short circuit current of 4.0kA have been designed and manufactured on the basis of theoretical and computational analysis for its development. The eddy current analysis, the magnetic field analysis and the calculation of the rotational force on arcs have been conducted using FLUX2D package. The short circuit current interrupting tests have been conducted to the model interrupters using the simplified capacitive synthetic test circuit in KERI. The results show that the model interrupters have a sufficient interrupting capability and the new design concept is proper for a good interrupting performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.113-114
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• 2008

The purpose of this paper is to analyze AC Breakdown of solid/air composite insulation depending on the thickness and the pressure of dry air for eco-friendly insulation. SF6 gas has been widely used in electric equipment as gas insulation because of high dielectric strength and arc extinguishing performance. However, because SF6 gas is one of the green house effect gases, alternative insulation such as SF6 mixture, extremely low temperature gas, vacuum, liquid and solid insulating are being investigated.

• 한국대기환경학회지
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• 제14권5호
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• pp.397-410
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• 1998

Tracer experiments were performed 4 times in December 1992 on the relatively flat terrain and nearby building area adjacent to the Taedok Science Town in Korea. Each experiment was continued for relatively short period of 1 or 2 hours with intermittent release of SF6 up to 2.07g/s at 10m height. Movement of tracer plume was tracked by a continuous tracer analyzer installed on an air monitoring van. Simulation with INPUFF was carried out to analyze and predict experiments. Measured profiles of tracer plume were narrow and sharp while predicted profiles by INPUFF were broad and slowly varied. Tracer plumes were detected at a short distance of 0.5 to 2.2 km mainly due to intermittent release and high value of lower detectable limit. Various experimental conditions were tested by INPUFF simulation in order to find desirable conditions. Higher wind speed and less variable wind direction could yield longer distance of plume tracking only when the lower detectable limit was sufficiently low. Distance of plume tracking was long and did not much depend on the lower detectable limit in stable atmospheric conditions.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.159-162
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• 1998

This paper describes the electron transport characteristics in $SF_6$+He gas calculated for range of E/N values from 50~700[Td] by the Monte Carlo simulation and Boltzrnann equation method using a set of electmn collision cross sections determined by the authors and the values of electron swarm parameters are obtained by M F method. The results gained that the values of the electron swarm parameters such as the electron drift velocity, the electron ionization or attachment coefficents, longitudinal and h-ansverse diffusion coefficients agree with the experimental and theoretical for a range of E/N.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.289-290
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• 2008

The purpose of this paper is to analyze AC Breakdown of solid/air composite insulation depending on the thickness and the pressure of dry air for eco-friendly insulation. SF6 gas has been widely used in electric equipment as gas insulation because of high dielectric strength and arc extinguishing performance. However, because SF6 gas is one of the green house effect gases, alternative insulation such as SF6 mixture, extremely low temperature gas, vacuum, liquid and solid insulating are being investigated.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권11호
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• pp.556-562
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• 2001

Spacer is used between main tank and auxiliary tank for on load tap changer in gas insulated power transformer. This paper deals with electrical design of spacer and discusses different analysis method of between 2D FEM(finite element method) and 3D FEM. To design spacer, we modeled structure of two kind of coaxial cylinders of spacer conductors and analysised electric field of spacer at impulse and induced test voltage condition. Spacer has 13 conductors and electric field was changed according to arrangement of conductors. We could find out arrangement of conductors at which electric stress is minimum. And this arrangement was satisfied with actual test conditions.

• 대한전기학회논문지
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• 제33권3호
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• pp.106-111
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• 1984

Prebreakdown current pulses arising from avalanche growth in SF6 were recorded under static uniform field at pressures up to about 400kpa. At pressures less than 100kpa the current pulses consist of the electron component observed as the fast rise of current, the negative ioncomponent which is superimposed, and the positive ion component comprising the tail of the pulse. The values of positive ion drift velocity were measured from the present pulse data. At pressures in excess of about 100 Kpa the pulse shapes becam distorted such that quantitative analysis was no longer possible, and did not indicate the action of any photosecondary process at the cathode. Breakdown appers to result from the seperate development of single avalanche.