• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 학술대회 논문집
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• pp.223-227
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• 2004

False-tripping of MCCB(Molded Case Circuit Breaker) and ELB(Earth Leakage Circuit Breaker), using to protect overload and ground-fault accidents in power system raise direct and indirect losses like as information loss, facilities damage, slipup of goods production in industry place. Cause of false-tipping of MCCB and ELB is various and cause analysis of false-tripping is mostly made up by inference because trip is not reappeared. This paper investigated and analyzed causes and influences of false-tripping of MCCB and ELB by making up a question to safety managers of two hundred and eighteen electrical facilities for private use. Also, the necessity of experimental study on the effect of harmonics on false-tipping of MCCB and ELB was presented.

• 전력전자학회논문지
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• 제13권1호
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• pp.15-21
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• 2008

공장전기설비에서 개인용 컴퓨터, 정류기, 전기로와 시험장치 등의 비선형 부하 사용 증가에 따른 고조파 발생으로 누전차단기가 오동작하거나 불필요 동작을 하고 있다. 따라서 공장전기설비의 안전관리자를 대상으로 누전차단기의 오동작 상태에 대한 조사를 실시하였다. 또한 누전차단기가 오동작하거나 불필요 동작을 하고 있다는 수용가에서 전압, 전류, 고조파와 불평형 등 전력품질을 측정하고 분석하였다. 본 연구결과는 왜형된 전류파형으로 누전차단기의 트립특성 시험과 누전차단기 오동작 원인분석시 자료로 활용하고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.157.2-157
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• 2001

This paper describes the synergism of Artificial Neural Network and Fuzzy Logic based approach to improve the reliability of transformer differential protection, the conventional transformer differential protection commonly used a harmonic restraint principle to prevent a tripping from inrush current during initial transformer´s energization but such a principle can not performs the best optimization on tripping time. Furthermore, in some cases there may be false operation such as during CT saturation, high DC offset or harmonic containing in the line. Therefore an artificial neural network and fuzzy logic has been proposed to improve reliability of the transformer protection relay. By using EMTP-ATP the power transformer is modeled, all currents flowing ...

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 학술대회 논문집
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• pp.211-216
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• 2004

This paper presented a actual conditions on a false-tripping of ELB(Electrical Leakage Breaker) and an assessment of the harmonics due to non-linear electronic equipment such as personal computers, printers, fax machines, and test equipments in several office buildings. Actual conditions on a failure of ELB were surveyed and analyzed by making up a question to safety managers of in office buildings. Also, power quality measurements such as harmonic currents, voltage and current waveforms and current imbalance were made at various office buildings where nuisance tripping of ELB is often occurred. The results of this study can be used in making decisions regarding cause of ELB trip and operating md tripping characteristics test of ELB when subjected to distorted current waveforms.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.479-481
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• 2007

This paper presented a actual conditions on a false-tripping of ELB(Earth Leakage Breakers) and an assessment of the harmonics due to non-linear electronic equipment such as personal computers, rectifier, electric furnace and test equipments in plant installations. Actual conditions on a failure of ELB were surveyed and analyzed by making up a question to safety managers of plant installations. Also, power quality measurements such as harmonic currents, voltage and current waveform and current imbalance were made at various plant installations where nuisance tripping of ELB is often occurred. The results of this study can be used in making decisions regarding cause of ELB trip and operating and tripping characteristics test of ELB when subjected to distorted current waveform.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권10호
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• pp.479-484
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• 2002

Recently it is reported that many a malfunction of ELB which is represented by non-operated type ELB for an impulse wave, is caused by lightning impulse and transient ground potential rise due to nearby lightning strokes. In order to examine the cause of malfunction, 5 samples were investigated experimentally in this study. As each ELB has a different leakage current detecting circuit and wiring method, various characteristics were measured. As a result, all of them brought about malfunctions under the lightning impulse voltage less than 7 kV and the surge current less than 3 kA. Also the different aspects were measured with a polarity of injected surge and a position of MOV to protect the inner circuit of ELB. The Position and effects of protecting devices were suggested as a remedy.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1688-1690
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• 2002

The unpredictable threat of lightning surge is ever increasing in today's low-voltage power supplies. Thus Surge protection devices for AC mains are more widely used. The false-tripping of the earth leakage breaker (ELB) can be caused by the installation of surge protection devices with MOV. In order to examine the cause of malfunction, the malfunction characteristics of ELBs applied by lightning surge were investigated experimentally. As a result, all of them brought about malfunctions under 7 kV of the impulse voltage. The suitable position of MOV and use of zener diode were suggested to eliminate the problems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.205_206
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• 2009

Protection system is important part in distribution system. Protection system in power systems can fail either by not responding when they should(failure to operate) or by operating when they should not(false tripping). Customers has dissatisfied that due to the failure of protection system. The reliability of distribution system also has influenced. However, the failure of protection system can reduced by the maintenance. This paper has focused on malfunction of protection system. The approach is based on Markov models.