• Title/Summary/Keyword: Current limiting and discharge

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A Study of Measurement of Minimum Ignition Energy for Pine Tree Dust on Electrostatic Discharges (정전기 방전시의 소나무목분의 최소착화에너지 측정에 관한 연구)

  • 이동훈;박한석
    • Journal of the Korean Society of Safety
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    • v.13 no.3
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    • pp.74-79
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    • 1998
  • To establish measuring method for minimum ignition energy of explosive powders caused by electrostatic discharge, A measuring method(Hartman) using a very small quantity of pine tree testing powder was proposed, and the influence of discharge current limiting resistance connected in series into a capacitive discharge circuit on ignition energies of explosive powders was investigated. As a result the minimum ignition energy was 42.25mJ when discharge current limiting resistance 300 $k\Omega$.

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Current Limiting and Discharge Characteristics of High Tc Superconductive Fuse (고온 초전도 퓨즈의 한류 및 방전 특성)

  • Choi, Hyo-Sang
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.6
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    • pp.673-677
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    • 2004
  • We present the basic properties of a superconductive fuse (SF) based on YBCO/Au films. The SF consists of YBCO stripes covered with Au layers for current shunt. The fault current was limited to a designed value in less than 0.4 msec by resistance development in YBCO/Au upon quenching. This enabled the SF to transfer small fault power and the suppressed current was sustained for more than 0.5 msec while Au layer melting and arcing. The arcing time was less than 2.5 msec, that is short enough to do self-interruption. Under the source voltage of 100 $V_{rms}$, the longer the duration time of fault current was, the shorter its discharge time was. The duration time of fault current and its discharge time were reduced by increased voltages in the range of 200 - 300 $V_{rms}$. We thought that this was because the quench propagation was limited by local melting generated with higher voltage.age.

Operating characteristics of high Tc superconducting current limiting fuse at various voltages (고온 초전도 한류퓨즈의 전압별 동작특성)

  • Choi, Hyo-Sang;Hyun, Ok-Bae;Kim, Hye-Rim;Hwang, Si-Dole;Park, Kwon-Bae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.05c
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    • pp.161-163
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    • 2001
  • We present the basic properties of a superconducting current limiting fuse (SCLF) based on YBCO/Au films. The SCLFs consists of YBCO stripes covered with Au layers for current shunt. Under the source voltage of 100 $V_{rms}$, the longer the duration time of fault current was, the shorter its discharge time was. The duration time of fault current and its discharge time were reduced by increased voltages in the range of 200 - 300 $V_{rms}$. We thought that this was because the quench propagation was limited by local melting generated with higher voltage.

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Partial Discharge Measurement of Oil-Paper Insulation by Dual Measuring Impeadance (절연유-절연지에서 이중 임피던스에 의해 부분방전측정)

  • Kim, K.H.;Ryu, H.S.;Sun, J.H.
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1778-1780
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    • 1996
  • In this paper, we describe the partial discharge measurement with measuring impedance to have two wide frequency band transformers(filters) in the oil-paper and air insulation. The measuring impedance consists of high and low limiting frequency transformers. This measuring impedance could be measured the partial discharge current wave. We have the results that the amplitude partial discharge pulse ratio of low limiting frequency tranformer to high limiting frequency one is varied in the condition(in oil-paper insulation and air) to generate partial discharge.

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A Study on Development of Current Limiting solid-state AC circuit Breaker (한류형 반도체 교류 차단기 개발에 관한 연구)

  • Lee, Woo-Young;Kim, Yong-Joo
    • Proceedings of the KIEE Conference
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    • 1990.11a
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    • pp.73-77
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    • 1990
  • In this paper we describe the solid-state ac-circuit breaker which has the characteristic of both a half cycle circuit breaker and a current limiting circuit breaker. This circuit breaker has a current limiting resistor in order to surprises the fault current to a certain level and discharge the energe included in circuit inductor. We explain the effect of circuit parameter on transient phenomena of switch device by using EMTP and finally design the control circuit consisted synchronous closing circuit, over- current detecting circuit and sensing circuit of rate of rise of fault current.

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New electrode structure for reducing power consumption of PDPs

  • Jung, Hae-Yoon;Cheong, Hee-Woon;Lee, Tae-Ho;Whang, Ki-Woong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.69-72
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    • 2008
  • A new electrode structure is proposed in this paper which can increase the discharge efficiency of plasma display panels and also decrease the panel capacitance by decreasing the electrode area effectively. Even with the decreased electrode area, the proposed structure could suppress the requirement for increasing the voltage and improve efficiency by limiting the discharge current.

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Characteristics of a superconductive fuse according to applied voltages (초전도 퓨즈의 전압별 특성)

  • Choi, Hyo-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.05b
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    • pp.169-172
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    • 2004
  • We present the basic properties of a superconducting current limiting fuse (SCLF) based on YBCO/Au films. The SCLFs consists of YBCO stripes covered with Au layers for current shunt. Under the source voltage of 100 $V_{rms}$, the longer the duration time of fault current was, the shorter its discharge time was. The duration time of fault current and its discharge time were reduced by increased voltages in the range of 200 - 300 $V_{rms}$. We thought that this was because the quench propagation was limited by local melting generated with higher voltage.

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Design of Fuse Mounted Elbow Connector (퓨즈가 내장된 엘보접속재의 설계)

  • 최경선;이철호;송일근;권태종;권영복;한명관
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.383-386
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    • 2000
  • Fuse mounted elbow connector used for pad mounted transformer was designed and investigated. Requirements of electrical ratings such as partial discharge, ac withstand voltage and impulse voltage and material properties were proposed in accordance with IEEE 386 and pre-standard (PS) 147-219∼229 of KEPCO. The connector can be jointed with pad mounted transformer and current limiting fuse which is installed inside of the connector easily replaced with new one in the case of breakdown of the fuse. Electric field analysis was also introduced in other to verify the reliability of the design.

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Anodic Oxidation of Iodate to Periodate by Lead Peroxide Anode (전착과산화납양극에 의한 옥소산염 전해산화)

  • Chong Woo Nam;Hak Joon Kim
    • Journal of the Korean Chemical Society
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    • v.15 no.6
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    • pp.324-329
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    • 1971
  • In order to evaluate the mechanism of electrolytic oxidation of iodate and to determine the optimum conditions for the electrolysis, studies were made using the cells without diaphragm and the lead peroxide anode. Results are summarized as followings: 1) Current density vs. anode potential curve by lead peroxide electrode had the different limiting current densities from platinum electrode and was more positive than platinum electrode. 2) Additions of potassium bichromate in the electrolyte contribute to maintain high current efficiency. 3) In the acid and alkaline regions, the current efficiencies decreased by reduction of iodate and discharge of hydroxyl ion, so maximum current efficiency was shown at pH 7. 4) Higher current density lowered the current efficiency in the region of 60-80% conversion of iodate. 5) Influence of the conversion on current efficiency in the region of 60-80% conversion of iodate.

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A High Efficiency Electrolytic Cell by Superposing Pulsed Corona Discharge in Water (수중 펄스코로나 방전을 중첩한 고효율 강전해수 발생장치)

  • 이재용;김진규;정성진;박승록;문재덕
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.2
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    • pp.79-85
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    • 2001
  • A conventional electrolyzing cell has been made by an ion exchange membrane inbetween parallel plate electrodes. A low dc voltage is applied to the electrodes for electrolyzing and the efficiency is remained in low. in this study, a novel electrolyzing cell with a pair of slit-type third electrodes installed inbetween parallel plate electrodes has been proposed and investigated experimentally. And pulse power wa supplied to between each electrodes. This slit type of third electrodes can concentrate the strong electric fields at the every its edges to accelerate the electrolyzing powers, and to generate oxygen bubble discharges for generating oxidants. And moreover the slits eliminate the space charge limiting action and the temperature of the water by leaking out through the slits from electrolyzing region to outside of the main electrode region. As a result, it was found that a strong electorzed water of pH 2.8 and pH 10.5 and oxidants dissolved water of 1 [ppm] in acidic water were obtained with a tap water fed at the electric current of 2 [A], which however were several times higher oxidant and ion concentration quantity compared with the conventional cell.

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