• 대한전기학회논문지
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• 제32권7호
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• pp.227-233
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• 1983

Noticing that action of gaseous phase in insulating oil concerns to the discharging characteristics, I investigated the smalness pressure effects on quantity of the partial discharge and discharging pulse frequency. Tests are carried out between the niddle points in insulating oil at pressure being changed by gradual charge of inert gas Ar. At pressure as low as of 0.1-0.5 torr pulse frequency and maximum partial discharge reach peak while at pressure haigher than 20 torr no pulse is observed. The fact that pulse frequency has peak value at certain presure, which is changed either by charging Ar or by adding oil, implies that the action of gaseous phase depends on pressure. Test results are that partial discharge pulse are governed by pressure of Ar-charged oil, and less partial discharge pulses correspond to smaller bubbles whereas more partial descharge pulses correspond to larger bubbles.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 춘계학술대회논문집
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• pp.209-213
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• 2005

To enhance the reliability of distribution transformers in service and to reduce the cost of maintaining and replaceing these, the condition and life of those insulating system should be evaluated accurately and the time to replace should be determined economically. Since the transformer failures related to insulation failure indicates that the primary cause is normally mechanical failure of integrity due to loss of mechanical strength as a result of degradation, the tensile strength characteristics of paper during ageing under accelerated conditions in insulating oil and research trends for assessing the life of insulating paper were investigated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.253-256
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• 1997

Recently, mixture insulating oils is widely used in respect that the physical and the electrical properties is more excellentthan mineral oils, such as alkylbenzene oils and silicone oils, and that cost is lower than alkylbenzene oils or silicone oils. Also, it is important to research for the additive BTA(Benzotriazole) as a study for the phenomena of streaming electrification of mineral oils. So, mixture insulating oils class 7-2, is selected as a specimen in this experiments, and the contents of BTA in specimen are 0.2[ppm], 10[ppm] and 30[ppm], respectively. Then, the physical and the electrical properties for each specimen is made researches.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.361-364
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• 1995

The static charges are generated by streaming electrification phenomena when insulating oil flowing by force for the purpose of cooling at the internal of Ultra-high power transformer. In this thesis, their elimination method was studied. The falter represents a greet much electrification characteristics because falter has large interfaces with liquid. In this paper, the streaming-electrification phenomena of insulating oil by metal filter were measured by mesh number, oil flow rate, oil temperature and a kind of mesh and The effect of charge elimination by metal filter generated minus ion was measured.

• 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.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권2호
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• pp.243-248
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• 2015

We prepared semi-insulating CdTe for radiation detectors by isothermal annealing of single crystals grown by Bridgeman technique in a sealed quartz container filled with Sn vapor. The resistivity of CdTe:Sn samples thus obtained was of order of $10^{10}Ohm{\cdot}cm$ at room temperature with electrons lifetime of $2{\times}10^{-8}$ s, which is appropriate for the applications desired. Analysis of electric transport characteristics depending on temperature, sample thickness and voltage applied revealed the presence of traps with concentration of about $(4-5){\times}10^{12}cm^{-3}$ with the corresponding energy level at 0.8 - 0.9 eV counted from the bottom of conduction band. The conductivity was determined by electron injection from electrodes in space charge limited current mode.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 추계학술대회 논문집
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• pp.147-151
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• 1994

In order to investigate the dielectric characteristic insulating oil is chosen insulating oil for electric cable, and experiment is performed in the temperature range of 30∼120[$^{\circ}C$] and frequency range of 30∼1${\times}$10$\^$6/[㎐]. As a result, the observed linear decrease in tan $\delta$ value at the low frequency range is due to the influence of frequency, whereas the increase in tan $\delta$ value at high frequency range is contributed by the electrode's resistance and dielectric loss. The dipole moment and activation energy of specimen are obtained 1.22(debye) and 12.75∼18.66[㎉/㏖e] of high temperature region, 15.68 ∼ 20.6[㎉/㏖e] of low temperature region respectively.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.221-222
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• 2016

The replacement ratio of waste EPS was varied, and its effect on compressive strength and absorption capacity was investigated. According to the experimental results, The 28th day compressive strengths for the W/C 50% specimens were 17.5~21.2MPa, which was relatively low compared to the 13.6~22.2MPa of the W/C 70%.

• E2M - 전기 전자와 첨단 소재
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• 제7권3호
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• pp.236-242
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• 1994

In this paper, the streaming electrification characteristics of insulating oil were examined when the oil is contacted with solid materials in a circulating system. The streaming current($I_s$) increases with increasing oil velocity and temperature, and electrification properties depend on species of metal materials. $I_s$ in the gauze-contained electrification apparatus increases with increasing oil temperature below the temperature of 43[>$^{\circ}C$], but decreases above 43[>$^{\circ}C$]. On the other hand, $I_s$ is positive electrificated for the pipe of Fe, Cu, while it is negative electrificated for Sus. When insulating oil flows through a car fuel filter, $I_s$ increases linearly with increasing oil temperature.

• 전기학회논문지
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• 제67권9호
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• pp.1189-1196
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• 2018

7 type composites (40, 45, 50, 55, 60, 65, and 70 wt.%)were prepared for the environmentally friendly GIS Spacer. Five kinds of samples were prepared for optimization of the filler content ratio (MS: MA = 1: 9, 3: 7, 5: 5, 7: 3, 9: 1) of epoxy / microsilica and microalumina. As a result of evaluation of the partial discharge resistance characteristic, surface erosion is generally slowed down as the fill amount of micro silica is increased. Also, partial discharge resistance characteristics for the development of insulating materials with optimal mixing ratios of heterologous showed a higher partial resistance of discharge and a decrease in erosion, as the filler content ratio of micro silica was larger. In the future, various researches such as electrical, mechanical, and thermal studies will be needed to develop insulating materials that can commercialize power devices in environmentally friendly insulating gas.