• Title/Summary/Keyword: RCD

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The Analysis of Temperature and Electric Field due to Contact Failure in Power Substation (수변전설비에서 접점 불량에 따른 열 및 전계 분포 해석)

  • Kim, Ki-Joon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.5
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    • pp.307-311
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    • 2016
  • Although there are existing Residual Current Protective Device (RCD) including detect electric leakage and elements such as short circuit and surge, the occurrence of incidents caused by electric faults, including fire, are still constant. The purpose of this study is to analyze the causes of accidents through the electric field distribution in the interpretation of the fault contact breaker. Simulation results by the arc fault has shown the convergence of temperature and electric field to the defect. Through their simulation results, the main cause of erosion phenomena in circuit breaker bar is the electric arc by concentration of electric field not due to dissolve by temperature.

A Study on Development of Arc Fault Circuit Interrupter Used in House Distribution Line (옥내 배전선로용 아크차단기 개발에 관한 연구)

  • Kwak, Dong-Kurl;Choi, Jung-Kyu;Park, Young-Jic;Kim, Jin-Hwan;Son, Jae-Hyun
    • Proceedings of the KIPE Conference
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    • 2013.07a
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    • pp.546-547
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    • 2013
  • This paper proposes an arc fault circuit interrupter (AFCI) using the distorted voltage wave in electric arc faults. It perceives a voltage instantaneously at the time of voltage drop. and occurrence. It is an AFCI of the new concept which operates with high reliability. The primary reason of electric fire is arc and spark. It prevents an electric fire or an electric leakage accident with quick responsiveness. Earth Leakage Circuit Breaker(ELB), Molded_case Circuit Breaker (MCCB) or Residual Current Protective Device(RCD) can not cut off electric arc or spark to be a major factor of electrical fire. This theory will be able to intercept an arc or a spark. which occurrence with periodic. Consequently It raises a reliability and validates a practicality of RCD.

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Flyback-type Snubber of High Efficiency for 10kV IGCT in 7MW Wind Turbine Systems

  • Shirmohammadi, Siamak;Suh, Yongsug
    • Proceedings of the KIPE Conference
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    • 2015.07a
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    • pp.359-360
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    • 2015
  • 10kV IGCT has been recently developed and has the potential to push wind turbine systems to higher power and voltage rating. Converters employing IGCTs need snubber and OVP circuit to limit the rate of rise of current and peak over voltage across IGCT during turn on and off state respectively. The conventional RCD snubber which is used in such power converter dissipates a significant amount of power. In order to reduce the amount of energy lost by conventional RCD snubber, this paper proposes an isolated inductor snubber circuit that not only meets all of the IGCTs characteristics during on and off-state but also significantly saves the power loss. Loss analysis of conventional di/dt snubber and OVP circuit is performed for the 3-level NPC type back-to-back VSC supplied from grid voltage of 6.9kV. In comparison with the conventional snubber, isolated inductor snubber has a fewer number of components and improved efficiency leading to a reliable and efficient wind turbine systems.

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A Study on Development of Over-load Fault Prevention Apparatus using Distribution Line Voltage (배전선로 선로전압을 이용한 과부하 사고 예방장치 개발에 관한 연구)

  • Kwak, D.K.;Park, D.H.;Park, Y.J.;Jung, D.Y.;Kim, D.K.
    • Proceedings of the KIPE Conference
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    • 2012.07a
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    • pp.617-618
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    • 2012
  • Recently as the inactive response characteristics of the existing RCD(Residual Current protective Device) used on low voltage power distribution system, so control of overload and electric short circuit faults, major causes of electrical fires, are not enough. Therefore, this paper is proposed a prevention apparatus using neutral line voltage and semiconductor switching devices for the prevention of electrical disasters in low voltage power distribution system caused by overload or electric short circuit faults. The proposed prevention apparatus confirms the excellent characteristics in response velocity and accuracy in comparison with the conventional circuit breaker(RCD) through various operation performance analysis.

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Development of electric safety control system for incapable operation of ELB and MCB using the low voltage distribution line (저압 배전선로의 누전 및 배선용 차단기의 오동작 방지를 위한 전기안전 제어장치 개발)

  • Kwak, Dong-Kurl;Shin, Mi-Young;Jung, Do-Young;Kim, Hyo-Jin;Baek, Seong-Hyun;Choi, Byung-Seub
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.371-372
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    • 2007
  • 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), that is Earth Leakage Circuit Breaker(ELB) and Molded_case Circuit Breaker (MCB), 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 research development is proposed to a auxiliary control apparatus for RCD trip 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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A Study on the Correlation between CSEI-S (Core Seven-Emotions Inventory-Short Form) and MMPI-2 (Minnesota Multiphasic Personality Inventory-2) Subscales (핵심감정척도 단축형과 MMPI-2의 상관성 연구)

  • Shin, Haegue;Lee, Jae-Hyok
    • Journal of Oriental Neuropsychiatry
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    • v.32 no.3
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    • pp.155-166
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    • 2021
  • Objectives: To analyze correlation between CSEI-S and MMPI-2 subscales to provide evidence for clinical application of the CSEI-S. Methods: Survey data of CSEI-S and MMPI-2 from 109 university students were analyzed. Demographic characteristics were subjected to descriptive analysis. Mann-Whitney U test and Pearson's correlation analysis were performed for CSEI-S and MMPI-2 scores. Results: The CSEI-S scale Joy (喜) showed a negative correlation with MMPI-2 clinical scales Hs, D, Hy, Pd, Pa, Pt, Sc, and Si. Six negative emotion scales of the CSEI-S showed positive correlations with MMPI-2 clinical scales except Mf and Ma. The CSEI-S scale Joy (喜) showed negative correlations with MMPI-2 restructured clinical scales RCd, RC1, RC2, and RC7. Six negative emotion scales of the CSEI-S showed positive correlations with restructured MMPI-2 clinical scales. The 60T-and-over group of MMPI-2 clinical scales D, Pd, Pa, Pt, Sc, Si, and Si showed significantly higher negative emotions than other groups. The 60T-and-over group of MMPI-2 scales D, Pt, Sc, and Si showed significantly lower Joy (喜) score than other groups. The 60T-and-over group of MMPI-2 restructured clinical scales RCd, RC2, RC3, RC6, RC7, RC8, and RC9 showed significantly higher negative emotions than other groups. The 60T-and-over group of MMPI-2 scales RCd, RC6, and RC7 showed significantly lower Joy (喜) scores than others. Conclusions: The CSEI-S showed consistent results with the original CSEI and MMPI-2 subscales. Thus, is a useful diagnostic tool in clinical practice.