• 제목/요약/키워드: Electric leakage

검색결과 584건 처리시간 0.028초

직류전동차용 피뢰기 진단기술 (Diagnostic Techniques of Lightning Arresters for DC Electric Traction Vehicles)

  • 길경석;송재용;김일권;문승보;신광철
    • 한국철도학회논문집
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    • 제9권4호
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    • pp.357-361
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    • 2006
  • This paper dealt with the performance evaluation and the diagnostic techniques of lightning arresters for DC electric traction vehicle. Field Measurements on the protective operation of lightning arresters against surge currents were carried out on running vehicles to acquire the data necessary for the diagnosis. The frequency and the magnitude of surge events were analyzed. Surge currents of $1\sim3$ times were recorded in one running service route and their magnitudes were ranges of $150A\sim2kA$. Also, an acceleration experiment on a lightning arrester by the standard lightning impulse current of 8/20 us and 5 kA was performed to know the aging characteristics. After the surge current application of 3,000 times, the reference voltage decreased by 4.5 %, and the leakage current was below 10 uA at the continuous operating voltage and about 50 uA at the rated voltage. From the experimental results, we propose a decision level of leakage current for the arrester used in this paper and designed an arrester tester which analyzes arrester condition by the magnitude of leakage current.

고정밀 전류센서를 이용한 이중 차단용 전기화재 방재장치에 관한 연구 (A Study on Electrical Fire Disaster Prevention Device used in Double Circuit Break)

  • 박동필;곽동걸;정도영;김춘삼;신호준
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 제39회 하계학술대회
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    • pp.2102-2103
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    • 2008
  • The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The occurrence factor of the fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Device(RCD) of high sensitivity type used at low voltage wiring cuts off earth leakage and overload, but the RCD can't cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied low voltage distribution panel are prescribed to rated breaking time about 30[ms](KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To be improved on such problem, this paper is proposed to a electrical fire disaster prevention device(EFDPD) for a RCD trip or a self circuit-breaking function on electric arc or spark due to electrical fire. Some experimental results of the proposed apparatus is confirmed to the validity of the analytical results.

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Evaluation of 0ff-gas Characteristics in Vitrification Process of ion-Exchange Resin

  • Park, S. C.;Kim, H. S.;K. H. Yang;C. H. Yun;T. W. Hwang;S. W. Shin
    • Nuclear Engineering and Technology
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    • 제33권1호
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    • pp.83-92
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    • 2001
  • The properties of off-gas generated from vitrification process of ion-exchange resin were characterized. Theoretical composition and flow rate of the off-gas were calculated based on chemical composition of resin and it's burning condition inside CCM. The calculated off-gas flow rate was 67.9Nm$^3$/h at the burning rate of 40kg/h. And the composition of off-gas was avaluated as $CO_2$(41.4%), steam(40.0%), $O_2$(13.3%), NO(3.6%), and SO$_2$(1.6%) in order. Then, actual flow rate and composition of off-gas were measured during pilot-scale demonstration tests and the results were compared with theoretical values. The actual flow rate of off-gas was about 1.6 times higher than theoretical one. The difference between theoretical and actual flow rates was caused by the in-leakage of air to the system, and the in-leakage rate was evaluated as 36.3Nm$^3$/h. Because of continuous change in the combustion parameters inside CCM, during demonstration tests, the concentration of toxic gases showed wide fluctuation. However, the concentration of CO, a barometer of incompleteness of combustion inside CCM, was stabilized soon. The result showed quasi-equilibrium state was achieved two hours after feeding of resin.

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고온 다결정 실리콘 박막트랜지스터의 전기적 특성과 누설전류 특성 (Electrical Characteristics and Leakage Current Mechanism of High Temperature Poly-Si Thin Film Transistors)

  • 이현중;이경택;박세근;박우상;김형준
    • 한국전기전자재료학회논문지
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    • 제11권10호
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    • pp.918-923
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    • 1998
  • Poly-silicon thin film transistors were fabricated on quartz substrates by high temperature processes. Electrical characteristics were measured and compared for 3 transistor structures of Standard Inverted Gate(SIG), Lightly Doped Drain(LDD), and Dual Gate(DG). Leakage currents of DG and LDD TFT's were smaller that od SIG transistor, while ON-current of LDD transistor is much smaller than that of SIG and DG transistors. Temperature dependence of the leakage currents showed that SIG and DG TFT's had thermal generation current at small drian bias and Frenkel-Poole emission current at hight gate and drain biases, respectively. In case of LDD transistor, thermal generation was the dominant mechanism of leakage current at all bias conditions. It was found that the leakage current was closely related to the reduction of the electric field in the drain depletion region.

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다결정 실리콘 TFT의 누설전류 모델링에 관한 연구 (A Study on the Modeling of Leakage Current in Polysilicon TFT)

  • 박정훈;이주창;김영식;이동희;성만영
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1993년도 하계학술대회 논문집 B
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    • pp.1250-1252
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    • 1993
  • Enhancement mode n-channel TFT leakage current(off current : $V_G<0$) that is little agreement on the conduction mechanism is major disadvantage of poly-silicon TFT in practical use, characteristic analysis and model ing. In this paper, new modeling of leakage current is proposed. The activation energy of leakage current, which is dependent on gate voltage, and leakage current dependent on poly silicon thickness are plausibly explained with this model. This model indicate that the reduction of leakage current is attributable to a decrease of maximum laterial electric field strength in the drain depletion region and to the density of trap.

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누전차단기가 설치된 옥내전로에서의 화재위험성 (Electrical fire hazards in the domestic circuit protected by Electric Leakage circuit Breaker(ELB))

  • 홍성호;김두현;김상철;김상렬
    • 한국산업안전학회:학술대회논문집
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    • 한국안전학회 1998년도 추계 학술논문발표회 논문집
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    • pp.335-340
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    • 1998
  • This paper presents a study on the electrical fire hazards of leakage current in a distribution circuit simulating a domestic circuit for low voltage. In this simulated circuits, total charges and energy of leakage current are calculated by a theoretical approach and compared with the results obtained from experiments, The approach and results become a cornerstone for studying and analyzing causes of electrical fires.

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Analysis of post-construction deformation characteristics of concrete faced rockfill dams

  • Kim, You-Seong;Won, Myoung-Soo;Song, Young-Chul;Yoon, Deok-Joong
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2007년 가을학술발표회
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    • pp.528-541
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    • 2007
  • To get the possible for management and maintenance, it was analyzed the deformation characteristics, such as crest of embankment and concrete face slab, and leakage of concrete faced rockfill dams (CFRD). There are trends that embankment deformation depends on intact strength used rockfills rather than dam height, deformation normal to concrete face slab during the first reservoir filling is occurred more than 80% of the total deformation in general, and the magnitude and trend of concrete face slab deformation is similar to post-construction crest settlement. The results showed that the range of post-construction crest settlement suggested by Sherard and Cooke (1987), and Clements (1984) had a good agreement in the cases using rockfill with very high intact strength, but it had a trend which underestimated crest settlement in the cases using rockfill with medium to high intact strength. The maximum leakage rate in general was observed during the first reservoir filling and long-term leakage rate was rapidly increased when the dam height exceeds approximately 120m.

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태양광발전시스템용 직류 누설전류 센서 개발 (Development of DC Leakage Current Sensor for Solar Power Generation System)

  • 김희선;한송엽;한후석
    • 전기학회논문지
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    • 제63권6호
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    • pp.828-833
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    • 2014
  • Grid connected transformerless solar power generation system is frequently used with the benefits of cost and efficiency. However, significant DC leakage current can flow from the DC line into the ground with dielectric breakdown in the transformerless solar power generation system. The leakage current occurred in the DC line causes accidents such as fire and electric shock on human. To resolve this problem, high sensitivity DC leakage current sensor is needed. But recently the studies on safety of DC line are not performed. In this paper, a high sensitivity DC leakage current sensor that can detect DC leakage current in solar power generation system, is proposed. Based on the studies, DC leakage current sensor is fabricated and characteristic tests are carried out. Finally, the accuracy of sensor performance is verified by leakage current experiments in solar power generation system.

전기철도 누설전류의 희생양극법을 이용한 전식 방지에 관한 연구 (A study on the prevention of the electric corrosion by leakage current using the Life of Sacrificial Anode in electric railway)

  • 염성배;박준열;임명환;박상욱;강아람
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 2009년도 추계학술대회 논문집
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    • pp.379-382
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    • 2009
  • 최근 KTX의 등장으로 기존에 조금씩 논의 되어오던 누설전류에 의한 전기부식이 전면적으로 등장하고 있다. 대전류를 필요로하는 KTX의 주변 지하매설물의 부식이 심각한 수준에 이르렀다. 따라서 이에 대한 대책이 시급한 상황이다. 전기부식을 방지하는 방법에는 몇 가지가 대두되고 있으나 경제성과 효율성을 고려하여 희생양극법을 이용하는 방법이 가장 알맞다고 판단한 바 본 논문에서는 이에 대해 기술하였다.

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Wire Rope형 진동완충장치 개발 (Development of Wire Rope Snubbers)

  • 박종범;안용호;배병홍;김민배
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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    • pp.334-336
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    • 1999
  • Piping systems of the power generating stations have been generally protected by hydraulic and mechanical snubbers which can allow large displacements arising from temperature change while those can reduce or absorb stresses due to vibrations. However these snubbers require amounts of budget for maintenance or replacement because of the leakage, lubrication and finally short life cycle. Recently the snubbers consisted of wire rope have been proved to reduce vibrations of piping systems. While the wire rope snubbers are free of maintenance such as leakage and lubrication imported price are so high. Now it is necessary to design. manufacture and certificate these wire rope snubbers.

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