• Title/Summary/Keyword: DC breakdown

검색결과 188건 처리시간 0.023초

초미소간격(超微小間隔)과 극단(極端)펄스방전(放電)을 이용(利用)한 미연소탄소립자(未燃燒炭素粒子) 소각제거기술(燒却除去技術) 개발기초연구(開發基礎硏究)(I) (초미소간격(超微小間隔)의 방전현상(放電現象)) (A Basic Study on a New Type Particulate Emission Control Means of a Power Station Using a Micro-Gap and a Pulse Discharge (Micro-Airgap Discharge Phenomena))

  • 문재덕;신수연
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1993년도 하계학술대회 논문집 B
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    • pp.605-608
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    • 1993
  • Breakdown characteristics of a small rod-to-rod microairgap has been studied for obtain an optimum breakdown voltage and an airgap spacing to be used as an emission control means by the electrical arc-burning unburnt carbon particulates exhausted from a power station burner. It is found that the breakdown voltage at the rod-to-rod airgap spacing in the rang of $1{\sim}100{\mu}m$ decreased with decrease in the rod-to-rod airgap spacing. And there were no minimum breakdown voltage on a $V_b$-Pd characteristics which is known as the minimum voltage in Paschen's law in air atmosphere. Breakdown voltages of the airgap at the constant airgap spacing were $V_{b-dc}>V_{b-ac}>V_{b-pulse}$, and it was lowest for the pulse voltage applied. As a result, it is found that a pulse power was one of effective power compared with dc or ac to be used as such an unburnt carbon particulate emission control means and the airgap spacing became to several tens ${\mu}m$, then the breakdown voltages were down to several handreds voltages.

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고압 적층 칩 캐패시터의 유전체 두께 및 내부전극 형상에 따른 AC, DC 절연 파괴 특성 (The AC, DC Dielectric Breakdown Characteristics according to Dielectric Thickness and Inner Electrode Pattern of High Voltage Multilayer Ceramic Capacitor)

  • 윤중락;김민기;이석원
    • 한국전기전자재료학회논문지
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    • 제21권12호
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    • pp.1118-1123
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    • 2008
  • High voltage multilayer ceramic capacitors (MLCCs) are classified into two classes-those for temperature compensation (class I) and high dielectric constant materials (class II). We manufactured high voltage MLCC with temperature coefficient characteristics of C0G and X7R and studied the characteristics of electric properties. Also we studied the characteristics of dielectric breakdown voltage (V) as the variation of thickness in the green sheet and how to pattern the internal electrodes. The dielectric breakdown by electric field was caused by defects in the dielectric materials and dielectric/electrode interface, so the dielectric thickness increased, the withstanding voltage per unit (E) thickness decreased. To overcome this problem, we selected the special design like as floating electrode and this design affected the increasing breakdown voltage(V) and realized the constant withstanding voltage per unit thickness(E). From these results, high voltage application of MLCCs can be expanded and the rated voltage can also be develop.

2,3 성분 상호침입망목 에폭시 복합재료의 절연 파괴 특성에 관한 연구 (A study on the dielectric breakdown properties of two and three interpenetrating polymer network epoxy composites)

  • 김명호;김경환;손인환;이덕진;장경욱;김재환
    • E2M - 전기 전자와 첨단 소재
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    • 제9권4호
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    • pp.364-371
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    • 1996
  • In this study, in order to investigate the applicability of IPN structure to epoxy resin which has been widely used as electrical and electronic insulating materials, DC dielectric breakdown properties and morphology were compared and analyzed according to variation of network structure, using the single network structure specimen formed of epoxy resin alone, interpenetrating polymer network specimen formed of epoxy resin/methacrylic acid resin, and interpenetrating polymer network specimen formed of epoxy resin/methacrylic acid resin/polyurethane resin. As results of the measunnent of DC dielectric breakdown strength at 50[.deg. C] and 130[>$^{\circ}C$], IPN specimen formed of epoxn, resin 100[phr] and methacrylic acid resin 35[phr] was the most excellent, and which corresponded to the SEM phenomena. The effect of IPN was more remarkable at high temperature region than at low temperature region. It is supposed that the defect of epoxy resin, dielectric breakdown strength is lowered remarkably at high temperature region, be complemented according to introducing IPN method.

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A study on the barrier effect with respect to the condition of solid insulation materials in GN2

  • Lee, Hongseok;Mo, Young Kyu;Lee, Onyou;Kim, Junil;Bang, Seungmin;Kang, Jong O;Nam, Seokho;Kang, Hyoungku
    • 한국초전도ㆍ저온공학회논문지
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    • 제17권1호
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    • pp.44-47
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    • 2015
  • High voltage superconducting apparatuses have been developed presently around the world under AC and DC sources. In order to improve electrical reliability of superconducting apparatuses with AC and DC networks, a study on the DC as well as the AC electrical breakdown characteristics of cryogenic insulations should be conducted for developing a high voltage superconducting apparatus. Recently, a sub-cooled liquid nitrogen cooling system is known to be promising method for developing a high voltage superconducting apparatus. A sub-cooled liquid nitrogen cooling system uses gaseous nitrogen to control the pressure and enhance the dielectric characteristics. However, the dielectric characteristics of gaseous nitrogen are not enough to satisfy the grade of insulation for a high voltage superconducting apparatus. In this case, the application of solid insulating barriers is regarded as an effective method to reinforce the dielectric characteristics of a high voltage superconducting apparatus. In this paper, it is dealt with a barrier effect on the DC and AC dielectric characteristics of gaseous nitrogen with respect to the position and number of solid insulating barriers. As results, the DC and AC electrical breakdown characteristics by various barrier effects is verified.

피뢰기를 고려한 자가용 전기설비 인입선로의 직류누설전류시험에 관한 연구 (A Study on the DC Leakage Current Test for Power Cable of Private Electrical Facilities considering Lightning Arrester)

  • 정기석;길형준
    • 전기학회논문지
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    • 제67권1호
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    • pp.142-147
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    • 2018
  • Private electrical facilities are judged whether it is suitable for the insulation aging condition of their incoming underground cables using DC leakage current test method. In the case where the service point of utility is the secondary side of cut out switch installed in the electric pole, there is a problem that it is difficult to separate the lightning arresters(LA) because of their high position of the pole. Therefore, the field test voltage is applied at value lower than DC 30 kV, which are stated in the inspection guideline. However, this test could reduced the insulation performance of the LA by accelerating the electrical stress of the metal oxide varistor element in the pre-breakdown region. In this study, we analyzed the relationship between the DC test voltage and the leakage current using the non-destructive DC high voltage equipment with leakage current measurement function. The results show that the leakage current increases sharply above the specified test voltage. As a consequence, it could be contributed to improve insulation aging inspection method by selecting the possible test area on the VI characteristic curve of the pre-breakdown area of the LA.

Analysis on the electrical degradation characteristics of 2G HTS wires with respect to the electrical breakdown voltages

  • Kang, Jong O;Lee, Onyou;Mo, Young Kyu;Kim, Junil;Bang, Seungmin;Lee, Hongseok;Lee, Jae-Hun;Jang, Cheolyeong;Kang, Hyoungku
    • 한국초전도ㆍ저온공학회논문지
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    • 제17권3호
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    • pp.37-40
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    • 2015
  • Recently, the electrical insulation design for electrical apparatuses is important to cope with the tendency of high voltage. The degradation characteristics of a superconducting coil due to an electrical breakdown should be considered to design a high voltage superconducting coil. In this paper, the degradation characteristics of 2G high temperature superconducting (HTS) wires are studied with respect to electrical breakdown tests. To analyze the dependency of the degradation characteristics of 2G HTS wires, the electrical breakdown tests are performed with AC(alternating current) and DC(direct current) voltage. All tests are performed by applying various magnitudes of AC and DC breakdown voltages. To verify the degradation characteristics of 2G HTS wires, the tests are performed with various 2G HTS wires with respect to stabilizer materials. The degradation characteristics of 2G HTS wires, such as Ic(critical current) and index number are measured by performing electrical breakdown tests. It is found that the characteristics such as Ic and index number can be degraded by an electrical breakdown. Moreover, it is concluded that the degradation characteristics of 2G HTS wires are affected by the stabilizer material and applied voltages. The cross-sectional view of 2G HTS wires is observed by using a scanning electron microscope (SEM). As results, it is found that the degradation characteristics of 2G HTS wires are concerned with hardness and electrical conductivity of stabilizer layers.

액체질소 중 열기포 형상 및 절연 특성 (Shape and Dielectric Strength of Thermal Bubbles in Liquid Nitrogen)

  • 백승명;김해종
    • 한국전기전자재료학회논문지
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    • 제28권5호
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    • pp.326-331
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    • 2015
  • In this paper, we study the insulating properties of the liquid nitrogen(LN2) including the thermal bubbles. The shape of the thermal bubbles in accordance with the current change was observed in the 77 K and 65 K LN2. According to the temperature of liquid nitrogen, bubbles were generated differently. The round shape of the bubble is occurred in 77 K LN2. But the layer shape of bubble is occurred in 65 K LN2. When the bubbles present, the dielectric strength of liquid nitrogen is low. However, the breakdown patterns were different according to the electrode arrangement. AC breakdown voltage(BDV) was lower than the DC BDV due to the influence of bubbles. Therefore, the design of a high-voltage superconducting equipments should consider the bubbles.

Methacrylate/Polyurethane이 함유된 Epoxy 복합재료의 직류 절연 파괴 특성에 관한 연구 (A Study on the DC Dielectric Breakdown Properties of Epoxy Composites Containing Methacrylate/Polyurethane)

  • 김명호;김경환;이덕진;가출현;신성궝;김재환
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1994년도 하계학술대회 논문집 C
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    • pp.1357-1359
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    • 1994
  • In this study, in order to improve the problem that dielectric breakdown strength decrease remarkably at high temperature, simultaneous interpenetrating polymer networks method was Introduced so that epoxy insulating material could have stable temperature characteristics and stable dielectric breakdown characteristics at whole temperature range. So network structure of epoxy/$SiO_2$ composite material was changed by adding MA and MA/PU into epoxy resin. DC voltage is applied into the specimen fabricated by this method, and then the result was compared and investigated.

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$BaTiO_3$ 세라믹스의 절연파괴거동에 미치는 결정립 크기와 시편두께의 영향 (Grain Size and Thickness Effects of Electrical Breakdown Behavior of $BaTiO_3$ Ceramics)

  • 조경호;남효덕;박철우;이희영
    • 한국세라믹학회지
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    • 제33권11호
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    • pp.1217-1222
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    • 1996
  • Undoped barium titanate ceramic samples with high density were produced by using both high purity hydro-thermally synthesized and oxalate-derived powders. Sintering temperature was varied in the temperature range 128$0^{\circ}C$-140$0^{\circ}C$ to control the average grain sizes of the samples. Electrical breakdown test was performed at two different temperature with 3$0^{\circ}C$(below Tc) and 15$0^{\circ}C$ (above Tc) for samples immersed in silicon oil bath using 60kV dc power supply. From the experimental results at below and above Curie temperature the grain size and thickness dependence of electrical breakdown strength for BaTiO3 ceramics was presented and breakdown behavior was also studied.

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La2O3 Doped ZnO-Pr6O11계 바리스터 세라믹스의 전기적 성질 및 안정성 (Electrical Properties and Stability of La2O3 Doped ZnO-Pr6O11-Based Varistor Ceramics)

  • 남춘우
    • 한국세라믹학회지
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    • 제43권6호
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    • pp.383-388
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    • 2006
  • The varistor properties and DC accelerated aging characteristics of $ZnO-Pr_{6}O_{11}-CoO-Cr_{2}O_{3}$-based varistors were investigated at different $La_{2}O_3$ contents in the range of $0{\sim}2.0mol%$. The varistors doped with 0.5 mol% $La_{2}O_3$ exhibited good nonlinearity, with 81.6 in nonlinear coefficient. Increasing the $La_{2}O_3$ content further to 2.0 mol% caused the sintered density to increase, and the breakdown voltage and nonlinearity to decrease abruptly. The varistors with 0.5 mol% $La_{2}O_3$ exhibited the high electrical stability, with -1.14% in variation rate of breakdown voltage, -3.7% in variation rate of nonlinear coefficient, and +100% in variation rate of leakage current for specified DC accelerated aging stress condition (95% of breakdown voltage/$150^{\circ}C$/24 h).