• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.78-83
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• 2010

The domestic 30AFs that are currently being produced show many problems due to different instantaneous trip characteristics in case of short-circuit. The troubles may cause explosion by excessive short-circuit capacities and arc emission, which results in a wide range of blackout. The function and safety of the low voltage circuit breakers installed before the end load are very important. This paper presents an idea on the safety improvement of the low voltage circuit-breakers through the analysis of instantaneous trip characteristics of domestic 30AF circuit-breakers.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.6
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• pp.905-909
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• 2012

Recent WTO/TBT agreement was adopted by the IEC domestic. For this reason, low voltage electrical equipment was many Confusion arises. Low voltage circuit was also one of these. The case of low voltage circuit, existing domestic circuit breakers and circuit breakers IEC curve differs from the behavior of each other. If low voltage circuit breaker wrong facility, circuit breaker malfunction may occur due to the large property damage. In this paper, to solve these problems domestic circuit breakers and circuit breaker operation IEC curves were analyzed. And, through experiments suggested compatible breaker way.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.364-367
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• 2009

The role of the low voltage circuit breakers that are installed just before the load is very important for safety. This paper presents a test and analysis of the instantaneous trip characteristics of the Low Voltage 30AF(Ampere Frame) Circuit Breakers, which can be expected to be used for improving the safety of the Low Voltage Circuit Breaker.

• Journal of the Korean Society of Safety
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• v.37 no.6
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• pp.1-8
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• 2022

This study analyzed the characteristics of insulation resistance and operating time based on an accelerated degradation test of a low-voltage circuit breaker. The experimental sample used a molded case circuit breaker (MCCB) and an earth leakage circuit breaker (ELCB). After measuring the insulation resistance of the circuit breakers, the leakage current was affected by an external rather than an internal structure. Furthermore, the insulation resistance of the circuit breakers with accelerated degradation was measured using a Megger insulation tester. In the accelerated degradation test, aging times of five, ten, 15, and 20 years were applied according to a temperature derived using the Arrhenius equation. Circuit breakers with an equivalent life of ten, 15, and 20 years had increased insulation resistance compared to those with less degradation time. In particular, the circuit breaker with an equivalent life of ten years had the highest insulation resistance. Component analysis of the circuit breaker manufactured through an accelerated degradation test confirmed that the timing of the increase in insulation resistance and the time of additive loss were the same. Finally, after analyzing the operating time of the circuit breakers with degradation, it was confirmed that the MCCB did not change, but the ELCB breaker failed.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.127-129
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• 2002

A new type of fiber-reinforced polymeric materials for the main body and the arc chamber of the low-voltage circuit breakers was developed. The tensile and the flectional strength of the three kinds of thermoplastic resins for the cover of MCCBs(Molded case circuit breakers) increase much higher than those made of BMC that has been used. In a high current-breaking test, an experimental MCCB with the new insulating material showed no-cracks on the bodies.

• 전기의세계
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• v.25 no.4
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• pp.59-62
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• 1976

This study on the characteristics of the leakage circuit breakers handles the rolls of each itemized parts of the mentioned apparatus and their influence in determining of the characteristic curve of leakage circuit breaker. Furthermore the differential current transforms in the mentioned apparatus for detecting the fault is handled as a heavy point.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.37-38
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• 2006

In this paper, the fire characteristics of circuit breakers for low voltage during switching arcs were analyzed according to the characteristics of combustible materials. Arc dispersion and ignition process were taken by high speed imaging system and digital camera. In this experiment, four resistors were connected as loads. To discover the fire characteristics of circuit breakers by combustible materials, ethanol and cotton were installed as combustibles near contacts respectively. In case of ethanol, fire broke out near the contacts while switch was turned on and turned off. Whereas, in case of cotton, fire broke out near deteriorated contacts while switch was turned off.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.593-596
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• 2001

It is necessary for calculation of repulsion forces acting on the closed electric contacts flowing over-current, e.g. inrush current and overload currents, to do optimum design of switching devices. In this paper, the farces and flux densities generated by currents at the contact point when circuit breakers are in closed state are obtained by using 3D finite element methode. To be convinced of the results, we measure electrogmanetic repulsion forces on contacts by measuring voltage between opened contacts in MCCB.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.9
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• pp.59-64
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• 2015

IEC is an international standards which are used in many countries with Europe as the center. IEC standard is introduced in Korea according to WTO/TBT agreements, however until now there are no buildings in Korea which are designed applying IEC standard. Therefore, KEA(Korea Electric Association) is scheduled to construct Korean low voltage electrical installation integration test site which is designed applying IEC standard. In this paper, before being under construction of Korean low voltage electrical installation integration test site, power substation is modeled based on real design parameters and method to select circuit breakers and cables is presented applying IEC standard in the modeled power substation. EMTP(ElctroMagnetic Transient Program) is used for simulation program. EMTP which is power system analysis program is easy to model power system and power substation.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1665-1667
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• 2003

Recently, a breaking capacity increases with breaking method using gas pressure from ablation materials in low voltage circuit breakers. In this paper, we investigated arc quenching materials with spectroscopic method. Especially, Hydrogen spectrum was investigated because its dielectric characteristics are better than other gases. We selected two arc quenching materials, UP and PA6, that use in circuit breakers. They had hydrogen spectrums, but PA6 was better than UP in the qualitative aspect.