• Title/Summary/Keyword: Residual Current Device(RCD)

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Protection coordination between residual current device and surge protective devices in low-voltage consumer's installations (저압 수용가 설비에서 누전차단기와 서지방호장치 사이의 보호협조)

  • Lee, Bok-Hee;Kim, Hoe-Gu;Park, Hee-Yeoul;Ahn, Chang-Hwan
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.6
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    • pp.75-81
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    • 2013
  • In this paper, protection coordination between residual current devices and surge protective devices in low-voltage consumer's distribution systems are presented. In the case that a surge protrctive device(SPD) is located on the load side of an residual current device(RCD), when the surge is injected from the source side of the RCD, most of injected surge currents are split into the RCD and the protection coordination between the SPD and RCD is improper, three of 6 specimens experience unintended operation due to test impulse currents. Also when the surges is injected from the load side, a lot of the surge currents is split into the SPD, but a half of test specimens causes nuisance trip. Coordination between SPD and RCD is not valid. When installing SPD, it is important to select SPD after due consideration of the protection voltage level of metal oxide varistor embedded in RCD. It is expected that the results obtained from this work could be useful to improve the protection effects of SPD in low-voltage distribution systems.

Development of RCD Auxiliary Trip Device by using High Precision Current Sensor (고정밀 전류센서를 이용한 RCD 보조트립 장치 개발)

  • Kwak, Dong-Kurl
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.8
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    • pp.1532-1537
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    • 2009
  • Nowadays the diversity and large-capacity of electric appliances are strong effect on electrical fires augment in an alarming way. But, as the inactive response characteristics of the existing RCD (Residual Current protective Device) used on low voltage power distribution lines, so control of overload and electric short circuit faults, major causes of electrical fires, are not enough. Therefore this paper is confirmed the unreliability of the existing RCD by electrical faults simulation and is proposed a auxiliary trip device of RCD by using a high precision current sensor (namely, reed switch) for the prevention of electrical disasters in low voltage power distribution lines caused by overload or electric short circuit faults. The sensitive reed switch in the proposed ATD (auxiliary trip device) exactly detects the increased magnetic flux with the overload or the short current caused by a number of electrical faults, and then rapidly cuts off the existing RCD. The proposed auxiliary trip device of RCD is confirmed the excellent characteristics in response velocity and accuracy in comparison with the conventional circuit breaker through various operation performance analysis. The proposed ATD can also prevent electrical disaster, like as electrical fires, which resulted from the malfunction and inactive response characteristics of the existing RCD.

Development and Safety Estimation of Resistive Leakage Current(Igr) of Detection Outlet (저항성 누설전류(Igr) 검출 콘센트의 개발 및 안전성 평가)

  • Kim, Chang-Soung;Hanh, Song-Yop;Choi, Chung-Seog
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.2
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    • pp.221-226
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    • 2009
  • In this paper, we analyzed form of flowing leakage current in electrical installation. Leakage current ($I_g$) is consisted of resistive leakage current($I_{gr}$), capacitive leakage current($I_{gc}$), and inductive leakage current($I_{gl}$). Resistive leakage current($I_{gr}$) is big occasion than capacitive leakage current($I_{gc}$) in system, Residual Current Protective Device(RCD) detects correctly leakage current. But,$I_{gc}$ is big occasion than $I_{gr}$, RCD is malfunctioned It is resistance to lead to electric fire in electrical device. We manufactured outlet that resistive leakage current detecting circuit is had. Manufactured outlet displayed performance exactly in leakage current of 5 mA Therefore, this product estimates that contribute on electric fire courtesy call.

The Analysis of Oxidization Characteristics according to the shapes of RCD contacts (RCD 접점형태에 따른 산화특성 분석)

  • Kim, Dong-Woo;Kim, Hyang-Kon;Gil, Hyoung-Jun;Han, Woon-Kim;Choi, Chung-Seog
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.576-577
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    • 2005
  • In this paper, the oxidization characteristics were analyzed according to the shapes of Residual Current Protective Device(RCD) contacts. RCD is an electrical safety device specially designed to immediately switch the electricity off when electric leakage is detected at a level harmful to a person using electrical equipment. The shapes of RCD contacts are a little bit different according to the models. When RCD is turned on, stationary and moving contact do not fit together. So, it can cause the increase of contact resistance. To discover the deterioration characteristics of RCD contacts by switching repetition, the contacts were analyzed by stereo microscope, Scanning Electron Microscope(SEM) and Energy Dispersive X-ray Spectrometer(EDS).

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Electrical Fire Disaster Prevention Device of Double Protection using a High Precision Current Sensor in Low Voltage Distribution System (고정밀 전류센서를 이용한 저압배전계통 이중 보호용 전기화재 방재장치)

  • Kwak, Dong-Kurl;Jung, Do-Young
    • Fire Science and Engineering
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    • v.23 no.3
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    • pp.40-47
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    • 2009
  • Nowadays the diversity and large-capacity of electric appliances are strong effect on electrical fires augment in an alarming way. But, 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 confirmed the unreliability of the existing RCD by electrical fault simulator and is proposed a Electrical Fire Disaster Prevention Device (EFDPD) by using a high precision current sensor (namely, reed switch) for the prevention of electrical disasters in low voltage power distribution system caused by overload or electric short circuit faults. The sensitive reed switch in the proposed EFDPD exactly detects the increased magnetic flux with the overload or the short current caused by a number of electrical faults, and the following, the EFDPD has double protection function which operates self circuit breaker or rapidly cuts off the existing RCD. The proposed EFDPD is confirmed the excellent characteristics in response velocity and accuracy in comparison with the conventional circuit breaker through various operation performance analysis. The proposed EFDPD can also prevent electrical disaster, like as electrical fires, which resulted from the malfunction and inactive response characteristics of the existing RCD.

A Study on the Life Time of RCD in Coastal Area (해안지역에서의 저압용 누전차단기 교체주기 연구)

  • Kim, Chong-Min;Choi, Myeong-Il;Shong, Kil-Mok;Seo, Jung-Youl;Shin, Jin-Yong;Kim, Chang-Hwan
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.1
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    • pp.85-92
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    • 2011
  • The role of RCDs(Residual Current Protective Device) that are installed before the load is very important for preventing electric shock and electrical fire. However, although fault rate of RCD is increasing due to deterioration and long period usage, the RCD is permanently used without a checking of performance evaluation and it causes the electrical accident. In this paper, the amount of airborne chloride is researched in domestic costal area and the accelerated life test is conducted using a salt water spray tester in order to decide the life time of RCD. Aa a result of an accelerated life test, the MTTF(Mean Time To Failure) of RCD is 110.81 hours and B10 life time of RCD is 45.81 hours for the all samples. when an accelerated life test result is applied to within 2 km costal area, the life time of RCD is predicted about 5 years.

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

  • Park, Dong-Pil;Kwak, Dong-Kurl;Jung, Do-Young;Kim, Choon-Sam;Shin, Ho-Joon
    • Proceedings of the KIEE Conference
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    • 2008.07a
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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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The Arc Dispersion Properties by Switching of High Sensitivity Type RCD Contacts (고감도형 누전차단기 접점의 스위칭에 따른 아크 비산 특성)

  • Choi Chung-Seog;Kim Dong-Woo;Kim Young-Seok;Lee Ki-Yeon
    • Fire Science and Engineering
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    • v.19 no.2 s.58
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    • pp.63-68
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    • 2005
  • In this study, the arc dispersion properties were analyzed according to switching of high sensitive type Residual Current Protective Device(RCD) contacts. Arc dispersion and ignition process was taken by high speed imaging system(HSIS). In this experiment, electric lamps(60 W) and heaters(950 W) were connected in parallel as loads. In case of normal RCD, it took about 2.3(ms) from the generation of arc to the extinction of uc. When arc was dispersed in normal RCD, it did not ignite cotton. Whereas, in case of RCD deteriorated by NaCl solution, the range of arc dispersion was wider and the arc lasted for 3.3[ms] more compared to normal RCD. And the arc ignited cotton. In order to prevent accidents caused by RCD, we should be careful of environmental factors, such as dust and humidity, and the parts of RCD should be used as incombustible materials.

A Study on Auxiliary Control Safety Apparatus for RCD Trip on Electric Arc and Spark Disasters - Using by Power Semiconductor Switching Device - (아크 및 스파크 재해에 대한 누전차단기 트립을 위한 보조제어 전기안전장치에 관한 연구 - 전력용 반도체 스위칭 소자 적용 및 응용 -)

  • Kwak, Dong-Kurl;Shin, Mi-Young;Jung, Do-Young
    • Fire Science and Engineering
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    • v.20 no.1 s.61
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    • pp.71-76
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    • 2006
  • 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 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.

A Study on Development of Open-Phase Protector Having Leakage Current Generation and Incapable Operation Prevention at Open-Phase Accident (결상 시 누전전류 발생과 오동작 방지 기능을 갖는 결상보호기 개발에 관한 연구)

  • Kwak, Dong-Kurl
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.1
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    • pp.182-187
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    • 2015
  • In the three-phase power system, when any one-phase or two-phases is open-phase, the unbalanced current flows and the single-phase power supplies to three-phase loads. Specially, motor coil and transformer coil receive over-current. As a result, great damage as well as electrical fire can occur to the power system. In order to improve these problems, this paper proposes that an open-phase detection device is designed by a new algorithm using electric potential difference between the resultant voltage of neutral point and ground, and a control circuit topology of open-phase protector is composed of highly efficient semiconductor devices. It improves response speed and reliability. The control algorithm circuit also operates the cut-off of a conventional residual current protective device (RCD) which flows an enforced leakage current to ground wire at open-phase accident. Furthermore, time delay circuit is added to prevent the incapable operation of open-phase protector about instantaneous open-phase not open-phase fault. The time delay circuit improves more reliability.