• Title/Summary/Keyword: Breakdown field

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The Electrical Characteristics of Varistor. (바리스터의 전기적 특성)

  • Hong, Kyung-Jin;Jang, Dong-Hwan;Cho, Jae-Cheol
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.05a
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    • pp.52-56
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    • 2001
  • The Breakdown electric field of ZnO semiconductor devices in voltage-current characteristics was increased by increasing of additive materials. The specimen that has not additive materials was not formed spinel structure. The critical voltage that has not spinel structure was 235[V]. When the additive materials has 0.5 and 2[mol%], the Breakdown electric field was 840 and 758[V] in each additive materials. The Breakdown electric field of varistors as a factor of voltage and current was increased by addition of oxide antimony. The varistors that has oxide antimony was linearly increased in low electric field.

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A Study on the Electric Field Analyses and Improvement of Insulation Characteristics on the Ribbed Spaced for GIS (GIS 립 스페이서에 대한 전계해석 및 절연특성 개선에 관한 연구)

  • 류성식;최영찬;곽희로
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.16 no.2
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    • pp.59-64
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    • 2002
  • This paper analyzed the effect of ribs on the breakdown characteristics when a metallic particle attaches on the various spot of GIS spacer, using electric field analysis. Also, it was compared with the experimental result of breakdown voltage characteristics for the spacer with a metallic particle on its various spot and with the shape, the length, and the thickness of the ribs varying. The results of electric field analysis show that the electric field concentration of the rib is more weakened than other parts and therefore it restrains the proceeding of streamer, which occurs at the breakdown. And it is verified through experiments that the breakdown voltage of the spacer with rib is higher than that of the spacer without rib. The breakdown characteristics depend on the shape, the length, and the thickness of the rib as well. Also, it is confirmed by the electric field analysis and the experimental results that the electric breakdown characteristics could be improved by rounding the rib edge.

Breakdown Characteristics of $SF_6/CF_4$ Mixtures under AC Voltages in Uniform, Nonuniform Field (평등, 불평등 전계에서 AC전압의 $SF_6/CF_4$ 혼합가스 절연내력 특성)

  • Sung, Heo-Gyung;Hwang, Cheong-Ho;Kim, Nam-Ryul;Huh, Chang-Su
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1334-1335
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    • 2008
  • Although many studies have been carried out about binary gas mixtures with $SF_6$, few studies were presented about breakdown characteristics of $SF_6/CF_4$ mixtures. At present study the breakdown characteristics of $SF_6/CF_4$ mixtures in uniform and nonuniform field was performed. The experiments were carried out under AC voltages. The sphere-sphere electrode whose gap distance was 1 mm was used and the point-plane electrode whose gap distance was 3 mm was used in a test chamber. $SF_6/CF_4$ mixture contained 20% $SF_6$ and 80% $CF_4$ and the experimental gas pressure ranged from 0.1 to 0.5 MPa. The results show that addition of $SF_6/CF_4$ mixtures increase AC breakdown voltages. In uniform field the breakdown voltages of gas were linearly increased according to the pressure. However in nonuniform field the breakdown voltages of gas were increased nonlinearly.

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V-t Characteristics in $SF_6-N_2$ Mixtures for Transient Impulse Voltages ($SF_6-N_2$ 혼합가스에서 과도임펄스전압에 대한 V-t특성)

  • Lee, Bok-Hui;Lee, Gyeong-Ok
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.9
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    • pp.456-465
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    • 2001
  • In this paper, breakdown voltages in $SF_6-N_2$ mixtures were experimentally investigated to understand characteristics of dielectric strength and physical phenomena in nonuniform field disturbed by a needle shape protrusion. The test voltages are the lightning impulse$(\pm1.2/44 \mus)$ and the damped oscillatory impulse$(\pm400 ns / 0.83 MHz)$ voltages which can be occurred by the operation of disconnecting switches in gas-insulated switchgears(GIS). The effects of the polarity and wave shape of the test voltages, and the gas pressure on the V-t characteristics were in detail examined. The V-t characteristic curves were measured in different two ways : (1) one is the method by taking the maximum voltage recorded at or prior to breakdown against the time to breakdown, that is, the Procedures recommended in IEC 60060-1, (2) the other is the method by taking the voltage at the instant of chopping against the time to breakdown. As a result, the V-t characteristics of $SF_6-N_2$ mixtures in nonuniform electric field were significantly affected by the polarity and wave shape of the applied voltages. The positive breakdown voltages resulted in lower breakdown voltages in the time ranges considered, and the V-t curves for the negative oscillatory impulse voltage were extended over the longer time range. For the lightning impulse voltages, the V-t curves obtained by IEC Pub. 60060-1 were nearly same with the V-t curves obtained by the voltage at the instant of chopping against the time to breakdown. It is clear that the actual breakdown voltages were much lower than the maximum voltages appearing at or prior to breakdown because of the displacement current produced as a result of the dV/dt during the oscillatory transient voltage app1ication. The scattering of the negative actual breakdown voltages was much larger than that of the positive.

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A Study on Electrical Characteristics of Trench Field Ring for Breakdown Characteristics (내압특성개선을 위한 트렌치 필드링 설계 및 전기적특성에 관한 연구)

  • Kang, Ey-Goo;Kim, Beum-Jun;Lee, Young-Hun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.1
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    • pp.1-5
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    • 2010
  • In this paper, we proposed trench field ring for breakdown voltage of power devices. The proposed trench field ring was improved 10% efficiency comparing with conventional field ring. we analyzed five parameters of trench field ring for design of trench field ring and carried out 2-D devices simulation and process simulations. That is, we analyzed number of field ring, juction depth, distance of field rings, trench width, doping profield. The proposed trench field ring was better to more 1000 V.

Analysis of Breakdown Voltage Dispersion and Breakdown Process in Mineral Oil (광유 중 절연파괴전압의 분산과 절연파괴진전 과정의 분석)

  • Lim, Dong-Young;Park, Sung-Gyu;Park, Cheol-Ho;Kim, Ki-Chai;Lee, Kwang-Sik;Choi, Eun-Hyeok
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.6
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    • pp.35-41
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    • 2015
  • This paper presents a breakdown voltage and a process of breakdown progress in mineral oil under an quasi-uniform field with decomposition products which occur after the oil discharge. The breakdown voltage in the oil revealed the characteristics of dispersion regardless of an electrode gap. The cumulative probability distribution was used to analyze the dispersion of the breakdown voltage. In addition, the process of breakdown progress in the oil can be reasonably described by the electron breakdown theory based on both electrons emitted from the cathode and ions by field-aided dissociation of the oil. The proposed breakdown process will be used for the basic data to explain the behavior pattern of the decomposition product to cause the dispersion of the breakdown voltage.

The Effect of Surface Roughness on Breakdown in Air (공기중 절연파괴에 있어서 전극표면의 요철에 의한 영향)

  • 오철한;김미태
    • 전기의세계
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    • v.28 no.11
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    • pp.33-36
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    • 1979
  • In a uniform field, when an electrode with a hemispherical protrusion is set in atmosphere, by applying the streamer breakdown criterion and the surface roughness factor, the effect of field distortion due to electrode surface roughness on breakdown is investigated theoretically. A quantitative relation between the threshold of breakdown and the air pressure times the heigh of protrusion is derived by the aid of a computor and the results are compared with that of SF$_{6}$./.

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A Study on The Surface Breakdown of Epoxy Composite in Silicon Oil (에폭시 복합체의 실리콘유중 연면파괴에 관한 연구)

  • 장인범;정인재;정일형;유재웅;오재한;김종헌;이준웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.06a
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    • pp.195-198
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    • 1998
  • In this paper, we study on the surface breakdown of Epoxy composite in silicon oil. Breakdown field strengths were simulated by using FEM with the experience data of surface breakdown of Epoxy composite. The surface endurance and field distribution (kV/mm) of Epoxy composite were calculated by FEM.

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The Breakdown Phenomena of N2 gas by RF Electric Field (라디오 주파수전계에 의한 질소가스의 브레이크 다운 현상)

  • 황기웅;노영수
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.35 no.5
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    • pp.199-204
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    • 1986
  • The breakdown phenomena of N2 gas by 13.56MHz electric field are very different from those under steady field. In this paper we analyzed the breakdown phenomena by using electron distribution function and diffusion equation. The second-order differential equation derived from the Boltzmann equation is solved for the electron distribution function. The ionization rate and diffusion coefficient are calculated using kinetic theory formulas. The breakdown condition is that the number of electrons produced by ionization equal the number diffusing to the walls of the discharge chamber. Theses theoretical breakdown electric fields are calculated by the computer and compared with the experimental values.

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A Study on Breakdown Voltage Improvement of the Trench IGBT by Extending a Gate Oxide Region beneath the Trench Gate (트렌치 케이트 하단의 게이트 산화막 확장을 통한 트렌치 IGBT의 항복전압 향상에 대한 연구)

  • Lee, Jae-In;Kyoung, Sin-Su;Choi, Jong-Chan;Sung, Man-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.74-75
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    • 2008
  • TIGBT has some merits which are lower on-state voltage drop and smaller cell pitch, but also has a defect which is relatively lower breakdown voltage in comparison with planar IGBT. This lower breakdown voltage is due to the electric field which is concentrated on beneath the vertical gate. Therefore in this paper, new trench IGBT structure is proposed to improve breakdown voltage In the new proposed structure, a narrow oxide beneath the trench gate edge where the electric field is concentrated is extended into rectangular shape to decrease the electric field. As a result, breakdown voltage is improved to 23%.

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