• JOURNAL OF ELECTRICAL WORLD
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• no.7 s.127
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• pp.100-102
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• 1987

변류기는 자가용 수전설비에서는 계측과 보호계전기를 동작시키기 위해 필요한 것이다. 변류기 중 CT라고 하는 것은 회로의 전류를 검출하여 전류계, 전력계, 역률계 등에 접속되는 외에 과전류계전기를 동작시켜 과부하나 단락사고시에 회로를 차단하여 고압기기를 보호한다. 또한 ZCT (영상변류기)는 지락전류는 검출하여 지락계전기를 동작시키는 역할을 한다. 여기서는 이와 같이 중요한 역할을 하는 변류기의 고장사례이다.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.8
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• pp.921-926
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• 2015

For the over-heat protection purpose in power strip devices, over-current detection/protection circuits, such as bimetal, switching circuit, and microprocessor-based relay circuit, have been widely setup in high-end products. Most of these circuits are connected to the power line in parallel and, thus, they are sensitive to the line voltage and current distortion. Moreover, these protection circuits are often costly and, therefore, it is hard to meet the commercial requirements. A low-cost over-current detection circuit with the contactless current transducer is designed and tested in this paper. The detection circuit is galvanically isolated from the power line and, thus, less sensitive to the line voltage distortion. The experimental results show that the proposed circuit accurately operates despite of its simple structure and low-cost electronic parts.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.419-424
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• 2011

The system-on-board detectable and controllable the electrical fires due to ground fault(GF), arc fault and overload is implemented. The system IC for controlling and preventing the electrical fires is available to this system. The GF detection circuit for detecting the electrical leakage current, the arc fault detection circuit and the overload detection circuit controllable the input voltage for flowing the overload current are designed. The GF detection circuit and the arc fault detection circuit are good operated to the electrical leakage current and the arc signal, respectively. It is confirmed that the overload detection circuit has shown no erratic operation with the noise or the load variation and is only operated at the overload condition.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.5
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• pp.22-28
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• 2002

A protection scheme for Unified Power Quality Conditioner (UPQC) is presented and analyzed in this paper. The proposed UPQC has the series active power filter operated as a high impedance k($\Omega$) to the fundamentals when the over current occurs in the power distribution system, and three control strategies are proposed in this paper. The first is the method by detecting the fundamental source current through the p-q theory,［1］ the second is the method by detecting the fundamental component of load current in Synchronous Reference Frame(SRF) and the third is the method by detecting the input voltage. When the over current occurs in the power distribution system, the proposed scheme protects the UPQC without additional protection circuits. The validity of proposed protection scheme is investigated through simulation results.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.281-282
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• 2016

영구자석 동기전동기의 회전자 위치검출센서를 사용하지 않는 센서리스 제어를 위해서는 모터에 인가되는 전압과 전류를 정확하게 알아야 한다. 일반적으로 영구자석동기전동기 모델기반의 회전자 위치검출 관측기에 사용되는 전압은 전류제어기의 출력인 전압지령 값을 사용한다. 그러나 전압지령 값은 인버터에 사용되는 데드타임의 영향으로 인해 실제 모터에 인가되는 전압과 차이를 갖는다. 특히 고속운전 시 과변조 구간에서의 전압지령 값은 실제 모터에 인가되는 전압과 큰 오차를 갖게 된다. 데드타임에 의한 전압 오차는 회전자 위치검출 오차에 미치는 영향이 비교적 작게 나타나지만, 과변조 구간에서의 전압 오차는 회전자 위치검출 오차를 매우 크게 만들어 센서리스 제어를 불가능하게 만들 수 있다. 본 논문에서는 추가적인 전압검출회로를 사용하여 모터에 인가되는 3상 전압을 검출하여 회전자 위치검출 관측기에 적용함으로써 과변조 구간까지 센서리스 제어 범위를 확장하는 방법을 시뮬레이션을 통하여 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.291-292
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• 2015

본 논문은 계통과 연계된 3상 전압원 인버터를 기반으로 한 BESS의 능동 단독 운전 검출 방법을 제안한다. 계통 전압의 불평형에서도 안정적으로 위상을 추종할 수 있는 DDSRF_PLL(Decoupled Double Synchronous Reference Frame_PLL)방식을 적용 하였으며, 검출된 위상각 정보를 통해 정상분 전류 제어기와 역상분 전류 제어기를 독립적으로 제어할 수 있게 된다. 이를 위해 IEEE 1547과 UL1741에서 제시하는 단독 운전 기준 시험 회로를 구성하여 PSCAD/EMTDC 소프트웨어를 통한 시뮬레이션과 5kw프로토타입 하드웨어 장치를 통해 제안된 단독 운전 검출 방법을 검증하였다.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.226-227
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• 2016

본 논문은 SiC Mosfet Gate Driver에서 Overcurrent상황 발생시 Mosfet 양단의 전압을 검출함으로써 스위칭 소자를 보호하는 Desaturation detction circuit에 대해 다룬다. IGBT와 다르게 SiC Mosfet의 경우 ohmic 영역과 saturation영역의 구분이 명확하지 않기 때문에 과전류 발생시 Mosfet 양단 전압을 검출하는데 어려움이 있다. 따라서 이를 보완하기 위하여 Mosfet drain측에 새로운 회로를 추가로 설계함으로써 이를 보완하여 효과적으로 양단전압을 검출한다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.3
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• pp.96-102
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• 2009

This paper deals with gate drive and power IC for high power devices(600V/200A and 1200V/150A). The proposed gate driver provides high gate driving capability (4 A source, 8 A sink), and over-current protected by means of power transistor desaturation detection. In addition, soft-shutdown function is added to reduce voltage overshoots due to parasitic inductance. This gate drive If is designed, fabricated, and tested using the Dongbu hitek 0.35um BCDMOS process.

• 전기의세계
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• v.28 no.7
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• pp.49-55
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• 1979

This paper describes the mechanisms which breaks A.C. over-current protection in low voltage load. For the high speed over-current protection, it consists of thyristor switching circuit by forced commutation, IC logic gate controlled circuit and over-current detector with reed switch. Under various duty conditions, breacker was carried out several experiments and discussions. The results are as follows; (1) over-current cut off is possible within a quarter cycle (4ms at 60Hz) and clear is at least ten times faster than its electromechanical equivalent. (2) as the forced commutation thyristor circuit breaker has capability of high speed break, equivalent surgy current capacity of switching thyristor is increased more than twenty times of its rated current. (3) breaker using solid state dose not produce any harmful arc during switching period. Therefore the breaker above described may be considered an effective over-current protector for soli state power devices in industrial applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1810-1816
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• 2009

In 2007, 9,128 fires were actually caused by electrical faults and these fires resulted in 29 deaths and 262 injuries. Arc-faults were one of the major causes of these fires. When an unintended arc-fault occurs, it generates intense heat that can easily ignite surrounding combustibles. But, because conventional circuit breakers only respond to overloads, short circuits, and leakage currents, the breakers do not protect against arcing conditions. This paper presents results obtained in experiments on ignition behavior of wire by series arc fault currents and techniques developed to detect the arc-faults. The developed technique was tested after installation to make sure that they are working properly and protecting the circuit. If the developed arc fault detection technique is applied, the electrical fires caused by an arc-fault can be reduced.