• Title/Summary/Keyword: Nuisance tripping

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Effect of Harmonics on Residual Current Protective Devices (고조파가 누전차단기에 미치는 영향)

  • Jeon, Jeong-Chay;Lee, Sang-Ick;Yoo, Jae-Geun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.3
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    • pp.84-89
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    • 2006
  • Tripping of residual current protective devices(RCPDs) caused by harmonics has been continuously reported, but no literature is available on the behavior of RCPDs caused by harmonics. This paper, in order to find out the effects of harmonics on RCPDs, investigated the present condition on malfunction of RCPDs and measured harmonics at buildings where nuisance tripping of RCPDs was often occurred. Also, the operational characteristics of RCPDs were tested by the harmonics synthesizer that can generate distorted waveform. Results of experiment detected that there was minimum tripping current of RCPDs when third harmonic added to the fundamental frequency. And it was found that the leakage current to cause tripping of RCPDs increased with more higher order harmonics added to the fundamental frequency.

Effect on Molded Case Circuit Breaker of Harmonic Current (고조파 전류가 배선용차단기에 미치는 영향)

  • Yoo, Jae-Geun;Choi, Myung-Il;Park, Chee-Hyun;Son, Jae-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.1
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    • pp.53-58
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    • 2008
  • This paper analyze the operating characteristic of MCCB due to the synthesize harmonic current. Four types of MCCBs, divided by the type of operation system and a principle of operation, tested with 200[%] of rated current. The test result nuisance tripping did not occur but the time delay characteristic of the hydraulic magnetic type MCCB is appeared. From the place where the synthesize harmonic content is high it is good the hydraulic magnetic type MCCB not to use.

Operating Characteristics of Molded Case Circuit Breakers by Harmonic Currents (고조파 전류에 의한 배선용 차단기 동작 특성)

  • Jeon, Jeong-Chay;Yoo, Jae-Geun;Lee, Sang-Ick
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.2
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    • pp.68-74
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    • 2006
  • Malfunction and nuisance tripping of molded case circuit breaker(MCCB) caused by harmonic currents have been reported. But no data is available on the behavior of MCCB under harmonic currents. This paper tested the effects of harmonic currents on four common types of MCCB(thermal, thermal magnetic, magnetic and electronic types). Results of experiment detected no nuisance tripping with any of the breakers tested under test currents, included harmonic current, below rated currents. Additionally it was found that varying harmonic loading conditions did not affect manufacturer specified trip times for thermal only and thermal magnetic circuit breakers. However, under overloaded conditions, trip times of the magnetic only circuit breakers were gradually slowed according to increasing of harmonic currents, and it could cause hazardous overheating of cables. So, the use of magnetic only circuit breakers in the place harmonic currents we serious must be avoided.

Failure of Earth Leakage Breaker and Power Quality Analysis in Office Buildings (사무용 빌딩에서의 누전차단기 오동작과 전력품질 분석)

  • Lee, Sang-Ick;Yoo, Jae-Geun;Jeong, Jong-Wook;Lim, Yong-Bae;Jeon, Jeong-Chay
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2004.11a
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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.

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Power Quality Analysis and Failure of Earth Leakage Breakers in Plant (공장전기설비에서의 누전차단기 오동작과 전력품질 분석)

  • Lee, S.J.;Yoo, J.G.;Jeon, J.C.;Jeon, H.J.;Heo, H.S.;Choe, G.H.
    • Proceedings of the KIPE Conference
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    • 2007.07a
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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.

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Power Quality Analysis and Failure Survey of Earth Leakage Breakers in Factory Electrical Installation (공장전기설비의 누전차단기 오동작 조사 및 전력품질분석)

  • Lee, Sang-Ick;Choe, Gyu-Ha
    • The Transactions of the Korean Institute of Power Electronics
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    • v.13 no.1
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    • pp.15-21
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    • 2008
  • 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 factory electrical installation. Actual conditions on a failure of ELB were surveyed and analyzed by making up a question to safety managers of factory electrical installation. Also, power quality measurements such as harmonic currents, voltage and current waveform and current imbalance were made at various factory electrical installation 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.

A Study on the Operating Characteristic of RCB by Synthesize Harmonic Current (복합고조파에 의한 누전차단기의 동작 특성 연구)

  • Yoo, Jae-Geun;Choi, Myung-Il;Park, Chee-Hyun;Son, Jae-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.1
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    • pp.59-63
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    • 2008
  • This paper analyze the operating characteristic of RCB due to the synthesize harmonic current. The RCB of rated sensitivity electric current with 30[mA] test to operating characteristic by synthesize harmonic current and it analyzed the tripping operation due to a harmonic current. The test result, the operating current of RCB changed by synthesize harmonic current.

수전설비의 사례에서 트립사고와 그 체크포인트

  • 대한전기협회
    • JOURNAL OF ELECTRICAL WORLD
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    • no.6 s.102
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    • pp.88-95
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    • 1985
  • 수전설비에서 트립사고의 원인으로서는 전기기기 배전의 고장(단락, 지락)에 의한 것, 과부하의 의한 것 등 당연히 동작해야 될 트립 외에 동작해서는 안될 때에 트립되는 이른바 Nuisance Tripping (불필요동작)이라고 하는 케이스가 있다. 담당 기술자를 곤란하게 하는 현상인데 그 발생요인을 이해해둔다면 대책을 수립하여 방지하는 것은 곤란한 일이 아니다. 과전류에서는 변압기 여자돌입전유가 주로 생각되는데 지로의 경우에는 미소한 사고에너지를 검출, 증폭하고 있기 때문에 몇 가지의 요인을 들수 있다. 여기서는 주로 지로에 의한 요인을 가급적 사례를 기초로 하여 들고 체고 포인트를 설명하기로 한다.

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Survey on the Malfunction of MCCB and ELB in Private Electrical Facilities (자가용 수용가에서 배선용 및 누전차단기 오동작에 대한 조사연구)

  • Yoo, Jae-Geun;Lee, Sang-Ick;Jeon, Jeong-Chay
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.2
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    • pp.87-93
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    • 2005
  • Recently, nuisance tripping or malfunction of MCCB(Melded Case Circuit Breaker) and ELB(Electrical Leakage Breaker) is being increased according as load circuits and equipments of electrical customers are various and complicated, but investigation of actual conditions on malfunction of MCCB and ELB was not implemented This paper investigated causes and influences of malfunction of MCCB and ELB by making up a question to electrical safety managers of two hundred and eighteen private electrical facilities. The results show that users above $70[\%]$ experienced malfunction of MCCB and ELB, and causes of malfunction are in order aging(above $25(\%)$), nuisance tripping $(above\;22(\%))$, goods badness$(above\;20(\%))$, abnormal power like as harmonics$(above\;20(\%))$ and others $(about\;9(\%))$. Also, second damages due to failure of MCCB and ELB are in order goods production, equipment trouble, information loss, business and operation interrupt, and others. The results of this study can be used in making decisions regarding causes of MCCB and ELB trip.

A Study on the Operating Characteristics of Molded Case Circuit Breakers according to Temperature Rise (온도상승에 따른 배선용 차단기의 동작특성에 관한 연구)

  • Jung, Da-Woon;Kim, Jae-Ho
    • Journal of the Korean Society of Safety
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    • v.30 no.5
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    • pp.8-13
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    • 2015
  • Molded Case Circuit Breakers (MCCBs) are typically used to provide over current protection for electrical safety caused by short circuit faults and overloads in indoor low voltage power systems. The MCCB automatically connects and disconnects loads from the electrical source when the current reaches a value and duration that will cause an excessive. However, the MCCB sometimes is not interrupted due to a malfunction, nuisance tripping, or in a fire. Ensuring electrical safety is very important in a indoor low voltage power system. This paper presents the operating characteristics of MCCBs according to a temperature rise from room temperature to 160 degrees Celsius delivered by a radiant panel heater. The ABS 54c(rated current: 30A) of the hydraulic magnetic trip type was used in the experiments. The signals of temperature, voltage, and current were measured using the high accuracy Signal Conditioning Extensions for Instrumentation (SCXI) measurement system with the LabVIEW program manufactured by National Instruments. The operating characteristics were measured as functions of current amplitude and ramp-up rate. The MCCB tripping time decreased as a result of increasing current amplitude and ramp-up rate under a temperature rise condition, because the temperature and level of the current are directly proportional to the tripping time. Additionally, an instantaneous operation was observed after 8 times of the rated current, and the MCCB began to melt a surface temperature of around 300 degrees Celsius of. The experimental results coincided well with the operating curve.