• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1451_1452
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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 depends on the shape, arrangement, and kinds of material of grids. This paper is focused on understanding the interrupting capability, more specifically of the grid and 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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1603-1605
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• 1994

Recently, Gas Circuit Breakers are rapidly replacing Vacuum Circuit Breakers in the medium voltage switchgear. This is due to the improved performance of - GCB in interrupting capability, price, weight, size etc., while the countermeasure to suppress the switching surges of VCB has not been satisfactory. Intensive research works on the GCB have been conducted in the world widely since 1980. Nowadays it is well known that the thermal expansion type GCB can provide- better performance than puffer type in the distribution power system. KERI has conducted researches in the GCB rated at 25.8kV 25kA with Jinkwang Co. using the thermal expantion principle since 1993. In this paper, the calculated results of electric and magnetic fields for the model GCB are presented and analyzed. The effect of permanent magnet used to improve the interruption capabilty at the low current level is also investigated. The design parameters for the interrupter inspected through the short-circuit tests conducted at high power laboratory of KERI.

• 조명전기설비학회논문지
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• 제17권5호
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• pp.60-67
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• 2003

본 논문에서는 개폐기의 EMC 성능 개선방안을 연구하였다. 개폐기와 제어함은 멀티 제어 케이블로 연결되었다. 또한 각 장치에는 많은 제어 케이블이 설치되었다. 이들 제어 케이블은 전자부품과 직접 연결된다. 그러므로 제어 케이블은 EMC 성능 향상에 중요한 요소이다. EMC 성능 개선방안으로 제어 케이블과 나란히 병렬접지도체 (Parallel Grinding Conductor, PGC) 설치를 제안하였다. 또한 개폐기 내에 설치된 전압 변성기의 2차 케이력은 차폐 케이블을 사용하고, 차폐의 양단을 접지하는 것을 제안하였다. 개선방안 적용 후 개폐기의 EMC성능이 향상되었음을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.31-35
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• 2001

IGCTs have established themselves as the power semiconductor of choice at medium voltage levels within the last few years because of their low conduction and switching losses. The trade-off between these losses can be adjusted by various lifetime control techniques and the growing demand for these devices is driving the need for standard types to cover such applications as Static Circuit Breakers (low on-state) and Medium Voltage Drives (low switching losses). The additional demands of Traction (low operating temperatures) and Current Source Inverters (symmetric blocking) would normally result in conflicting demands on the semiconductor. This paper will outline how a range of power devices can meet these needs with a limited number of wafers and gate units. Some of the key differences between IGCTs and IGBTs will be explained and the outlook for device improvements will be discussed.

• 한국정보통신학회논문지
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• 제9권3호
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• pp.570-575
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• 2005

저전압 전력계통에 사용되는 누전차단기의 서지에 대한 오동작은 심각한 문제이다. 본 논문에서는 누전차단기의 서지에 대한 영향을 분석하기 위하여 IEC 61009-1와 KS C 4613 규격에 따라 누전차단기를 시험하였다. 서지전압 시험은 국내외 규격에 모두 적용되고 있으며, 서지전류 시험에 대해서는 국제규격 IEC 61009-1에만 규정되어 있다. 실험결과로부터 누전차단기는 서지전압에 대해서는 강인하지만 서지전류에 대해서는 오동작을 발생시켰다. 실제로 누전차단기가 설치되어 있는 환경에서는 서지전류의 침입이 빈번하므로, 누전차단기는 서지전류에 의한 오동작 시험이 수행되어야 하며, 국내규격에도 누전차단기 시험에 서지전류에 의한 평가를 포함하여야 할 것이다.

• 한국초전도저온공학회지:초전도와저온공학
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• 제5권1호
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• pp.10-17
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• 2003

For limitation and interruption of short circuit currents from low voltage to extra high voltage applications, the electrical equipment including fuses and circuit breakers, are widely used today. But in order to anticipate increasing needs for effective and competitive device for limiting the growing fault current in electrical power systems, fault current limitation technologies and fault current limitation devices are widely introduced and investigated in these days. Furthermore, the applications of high temperature superconducting materials (HTSC) into the current limiting devices are new approach for developing of novel and effective col-rent limitation electrical equipment. In this research, the necessities of current limitation technology and the developed and developing current limitation devices for power systems are introduced. Finally, the investigation of resistive type fault current limiters which is under development by LG and KEPCO were introduced.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.501-502
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• 2006

In this paper, new and aging sample of MCCB and ELCB are investigated the main performance test such as short circuit test, mechanical and electrical endurance test, dielectric test and surge current test. The surface conditions of new and aging sample are analyzed by SEM, TGA and DSC. The ELCB occurred badness mainly in short circuit test and surge current test. The badness cause of short circuit test was confirmed due to imperfect contact of contact part.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.961-965
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• 1992

It is well-known that shock waves frequently occur inside the nozzle of the interrupter, and that they play important roles in the arc interruption. A model interrupter with two-dimensional dual-airflow nozzles was used for this experiment. The arc was ignited with 1.4 mil copper wire stretched between the electrodes which were spaced out 56 mm. The arc current of 60 to 230 A was achieved by adjusting the external resistance from 5.5 to 1.6 ohms. The arc tests have been conducted for investigating the air arc characteristics, and the effects of shock waves and nozzle pressure ratios on the arc voltage, the arc resistance, the arc power, and average electric field. The results of these tests have been analyzed to provide insights into the arc characteristics for gas circuit breakers. The average electric field is represented by the function of the arc current to show the negative E-I characteristic explicitly. The effects of shock waves and nozzle pressure ratios are shown to be significant for a circuit breaker performance.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.766-776
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• 2015

It is well known that series arc faults in Low Voltage DC (LVDC) distribution system occur at unintended points of discontinuity within an electrical circuit. These faults can make circuit breakers not respond timely due to low fault current. It, therefore, is needed to detect the series fault for protecting circuits from electrical fires. This paper proposes a novel scheme to detect the series arc fault using Wavelet Singular Value Decomposition (WSVD) and state diagram. In this paper, the fault detector developed is designed by using three criterion factors based on the RMS value of Singular value of Approximation (SA), Sum of the absolute value of Detail (SD), and state diagram. LVDC distribution system including AC/DC and DC/DC converter is modeled to verify the proposed scheme using ElectroMagnetic Transient Program (EMTP) software. EMTP/MODELS is also utilized to implement the series arc model and WSVD. Simulation results according to various conditions clearly show the effectiveness of the proposed scheme.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.700-702
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• 2005

The most electrical apparatus should be able to withstand short-time current and peak current during a specified short time until circuit breakers have interrupted fault current. It defines the short-time withstand ability of electric a apparatus to be remain for a time interval under high fault current conditions. It is specified by both dynamic ability and thermal capability. KERI(Korea Electrotechlology Research Institute) recently constructed the new short-time current and low voltage short circuit testing facilities. This paper shows short- circuit calculation of transformer and describes high current measuring system, and evaluate the result of short-time withstand test used in $3{\phi}$ 90MVA short-time current testing facilities.