• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.632-635
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• 2004

The purpose of this paper is to investigate the effect of arc current and contact velocity on the erosion of silver-based contact materials to be used in low voltage circuit breakers. The opening velocity during breaking, which is constant, ranges between 2m/s to 6m/s in the 415V $25kA_{rms}$. Contact erosion is evaluated by measuring the mass change of the cathode and anode. The results show that the increase in opening velocity from 2m/s to 6m/s leads to a decrease in the contact erosion. It is shown that the material transfer from one electrode to another depends on the transfer charge and the opening velocity of the contacts. The contact pairs of AgWC/AgCdO are superior to $AgWC/AgSnO_2In_2O_3$ or AgWC/AgC contact pairs in the contact erosion.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.717-718
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• 2006

최근 저압 기중차단기(ACB, Air Circuit Breaker)는 고압중전기 공인시험제도 및 저압전기기기 안전인증제도와 같은 강제인중 대상에서 제외되어 해당 성능에 대한 안전 사각지대에 놓여있다는 지적을 받아왔다. 본 논문에서는 현재의 ACB관련 규격 및 성능평가기술을 분석하고, 국제규격과의 비교 분석을 통하여 국제규격에 준하는 성능평가기술 및 규격을 제시하는 방안을 연구하였다. 특히 내년에 제정이 논의되고 있는 ACB관련 KS 규격의 제정 방향 및 KS 심사기준에 대한 진행방향 설정과 연구되어야할 성능평가기술을 제품성능 특성별로 제시하였다. 향후 본 논문의 성능평가기술 및 제안 방향이 KS규격 제정 및 활용에 중요한 근간을 제공할 것으로 기대한다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.898-899
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• 2007

최근 저압 기중차단기(ACB, Air Circuit Breaker)는 고압 중전기 공인시험제도 및 저압전기기기 안전인증제도와 같은 강제인증대상에서 제외되어 해당 성능에 대한 안전 사각지대에 놓여있다는 지적을 받아왔다. 이에 한국전기연구원에서는 산업자원부 표준화기술개발사업의 일환으로 기중차단기에 대한 표준화 사업을 수행하고 있다. 본 논문에서는 일반 배선용차단기나 누전차단기와는 시험방법 및 설비가 상이한 기중차단기의 동작 및 개폐특성 시험방법을 분석하고 해당 시험을 수행하기 위해 설계하여 구축한 시험설비에 대해 기술하고자 한다. 제안된 성능평가설비들은 기중차단기의 국내 시험은 물론 국제 시험에서도 신뢰성 있게 사용될 것으로 기대한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.394-394
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• 2009

Owing to the increasing number of intelligent homes(or called Smart home), the corresponding cost is much higher. Low voltage circuit breakers are widely used in the intelligent homes to interrupt fault current rapidly and to assure the reliability of the power supply. The distribution of magnetic field induced by arc current in the contact system of molded case circuit breaker(hereafter MCCB) depends on the shape, arrangement, and kinds of material of arc runner. This paper is focused on understanding the interrupting capability, more specifically of the arc runner, based on the shape of the contact system in the current MCCB. The magnetic driving force was calculated by using the flux densities induced by the arc current, which are obtained by three-dimensional finite element method. There is a need to assure that the optimum design required to analyze the electromagnetic forces of the contact system generated by current and the flux density be present. This is paper present our computational analysis on contact system in MCCB.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.93-98
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• 2001

Fatigue strength evaluation was carried out for the core support structure of a low voltage circuit breaker. The impact load acting on the core support was calculated based on the strains measured during operation. A three-dimensional finite element analysis was performed to determine local peak stresses for fatigue evaluation. Fatigue safety factors were calculated using the modified Goodman, Gerber, Soderberg, and modified Findley lines, considering the magnitude of the residual stress and impact load.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.9
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• pp.538-544
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• 2004

This paper presents the interruption capability of serial-hybrid type GCB (gas circuit breaker) compared with that of puffer type. First a puffer type model interrupter which has the stroke length of 80 mm has been designed and manufactured. And also, a serial-hybrid type interrupter which has the same design parameters as the puffer type interrupter except the serially arranged thermal-expansion chamber and puffer cylinder has been fabricated. Using a simplified synthetic test facility, the critical interruption capabilities of the two GCBs have been estimated. The critical di/dt, the critical dV/dt of ITRV (initial transient recovery voltage) and the minimum arcing time of the puffer type model GCB were 10.7 A/${\mu}\textrm{s}$, 5.5 kV/${\mu}\textrm{s}$, and 15.0 ms respectively. In the case of serial-hybrid type model GCB, each of the values was 16.6A/${\mu}\textrm{s}$, 11.5 kV/${\mu}\textrm{s}$ and 13.0 ms. As a conclusion of this work, it has been quantitatively confirmed that the hybrid type interrupter can obtain the sufficient interruption capability at the operating force which is so low that puffer type interrupter has not the interruption capability.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.1
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• pp.78-84
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• 2004

Low voltage circuit breakers which interrupt rapidly and raise the reliability of power supply are widely used in power distribution systems. In the paper, it has been investigated how much interrupting capability is improved by correcting the shape of the contact system in molded case circuit breaker(below MCCB), especially contacts and arc runner. Prior to the interrupting testing, it is necessary for the optimum design tc analyze electromagnetic forces on the contact system generated by current and flux density. This paper presents both our computational analysis and test results on contact system in MCCB

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.9
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• pp.78-84
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• 2022

An air circuit breaker (ACB) is an electrical protection device that interrupts abnormal fault currents that result from overloads or short circuits in a low-voltage power distribution line. The ACB consists of a main circuit part for current flow, mechanism part for the opening and closing operation of movable conductors, and arc-extinguishing part for arc extinction during the breaking operation. The driving mechanism of the ACB is a spring energy charging type. The faster the contact opening speed of the movable conductors during the opening process, the better the breaking performance. However, there is a disadvantage that the durability of mechanism decreases in inverse proportion to the use of a spring capable of accumulating high energy to configure the breaking speed faster. Therefore, to simultaneously satisfy the breaking performance and mechanical endurance of the ACB, its driving mechanism must be optimized. In this study, a dynamic model of the ACB was developed using the MDO(Mechanism Dynamics Option) module of CREO, which is widely used in multibody dynamics analysis. To improve the opening velocity, the Taguchi design method was applied to optimize the design parameters of an ACB with many linkages. In addition, to evaluate the improvement in the operating characteristics, the simulation and experimental results were compared with the MDO model and improved prototype sample, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.220-220
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• 2009

We are developing of the evaluation technique and system for testing the performance of circuit breaker using Simplified Synthetic circuit. This facility specification is up to 90[kApeak] and up to 300[kVpeak]. It is possible to verify the interrupting capability by using low-energy and reduce the development period and the cost.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.728_729
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• 2009

최근 태양광 발전설비 및 신재생에너지 보급이 확대됨에 따라 저압 직류차단기가 설치되고 있는 실정이다. 본 논문에서는 저압 직류차단기의 성능이 교류차단기와 어떻게 다른가를 분석하고, 더 나아가 국내 직류차단기에 대한 시험 기반구축의 현실과 향후 필요한 대책을 제시하였다.