• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권4호
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• pp.179-184
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• 2003

The pulsed power system is widely used for many industries and environments. Generally, we call the "RUST", the reddish brown surface, that was made on iron surface or some other metals, when they are contacted by water and air the main substance of rust is oxide-ionization. In other words, the chemical symbol of rust on iron surface is iron oxide(III) hydrate Fe203.nH2O. In this study, we have designed and fabricated our system which has a compact pulse generator with switching MOSFET. Also we have studied the metal-oxide removing characteristics using in the atmospheric arc discharge. It has been investigated their removing characteristics by the change of charging voltage and pulse repetition rates. From this result, we can find out that the removal area Is increased from 3.80 to 8.04[$\textrm{cm}^2$], when pulse duration is increased from 100[pps] to 400[pps]. 400[pps].

• 전기학회논문지
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• 제61권12호
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• pp.1953-1958
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• 2012

The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The occurrence factor of the fire is electric arc or spark accompanied with such electric faults, specially short circuit faults. Earth Leakage Circuit Breaker (ELB) and Molded_case Circuit Breaker (MCCB), that is, Residual Current Protective Devices (RCDs) used on low voltage distribution lines cut off earth leakage and overload, but the RCD can not cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied in low voltage distribution panel are prescribed to rated breaking time about 30ms(KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To improve such problem, this paper proposes a prevention apparatus using the line voltage drop of neutral wire and some semiconductor switching devices. Some experimental tests of the proposed apparatus confirm the validity of the analytical results.

• 대한전기학회논문지:전력기술부문A
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• 제48권12호
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• pp.1492-1497
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• 1999

High impedance fault(HIF) is defined as fault the general overcurrent relay can not detect or interrupt. Especially when HIF occur in residential areas, energized high voltage conductor results in fire hazard, equipment damage or personal threat. This paper proposes the model of the high impedance fault in transmission line using the ZnO arrester and resistance to be implemented within EMTP. The performance of the proposed model is tested on a typical 154[kV] korean transmission line system under various fault conditions. Wavelet transform is efficient and useful for the detection of high impedance fault in power system, because it uses variable windows according to frequency. In this paper, HIF detection method using wavelet transform can distinguish HIF form similar fault like arcfurance load, capacitor bank switching and line switching.

• 전력전자학회논문지
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• 제20권4호
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• pp.369-374
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• 2015

The circuit breaker in an electric power system is not operated when the voltage in the circuit breaker is higher than the rated transient recovery voltage (TRV). The TRV of a circuit breaker is characterized by re-ignition of the arc between two poles and determined by the value of connecting impedance. In this study, we simulated the peak value of TRV in the AC filter of the circuit breaker. The suitability of TRV is assessed by capacitive current switching test conditions defined by the international guide IEC62271-100.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 전기설비
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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.

• 전기의세계
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• 제28권7호
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• pp.49-55
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• 1979

본논문은 Thyristor를 이용하여 교류회로의 고장전류를 차단하는 기구에 대한 것이다. 즉 Thyristor 한류차단회로를 설정하고 게이트제어회로 과전류검출기를 설계하고 동작과정을 확인하였다. 결과에 있어서 (1) 고속차단이 가능하다(60Hz 교류에서 4ms이내) (2) 이 방식에 의하면 차단용량을 감소시킬 수 있다. (3) 적은 신호로 지체없이 동작한다. (4) 기계적부분이 없으므로 반영구시 수명을 가진다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2512-2514
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• 1999

A new zero voltage and zero current switching(ZVZCS) full bridge DC-DC converter with transformer isolation is proposed for arc welding machines. The proposed DC-DC converter uses an auxiliary transformer to obtain ZCS for leading leg, which provides load current control capability even in short circuit condition. The auxiliary circuit also operates in ZVZCS mode. The power rating of the auxiliary transformer is about 10% of the main transformer. The operation is verified by experiments for 12[KW] prototype.

• 전기의세계
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• 제34권11호
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• pp.685-691
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• 1985

전기가 널리 가정에 보급되어 사용되기 시작한지 약 100여년이 지나서야 power circuit를 making하거나 breaking하는 문제에 부닥치게 되어 여러가지 괄목할 만한 방법이 계속 발전해 나아갔다. 특히 breaking 할때에 발생하는 arc를 어떻게 처리하느냐에 따라 테크닉이 달라지고 문제의 해결점이 되는 것이다. 왜냐하면 이러한 물리적인 현상은 아주 높은 온도의 특수한 상황에서 발생하기 때문에, 그의 성격을 정확하게 충분히 알맞는 모델링을 한다는 것은 그리 쉬운 일이 아니다. 다라서 이러한 어려움을 다루는 것은 학구적인 연구를 하는 이들에게는 좋은 연구과제가 되고 있으나, switching aparatus를 사용하는 현장엔지니어들은 수학적인 모델이나 물리적인 문제점 보다도 실질적인 경험에 의하여 know-how를 터득하여 나가야 한다.

• 전기의세계
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• 제26권2호
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• pp.72-77
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• 1977

This paper is devoted primarily to a study of magnetic switch which does not produce any harmful are during the switching period using triacs. The arc-eliminating method presented in this paper experimentally obtained the desired results, and also we executed numerical analysis by computer. This method will be greatly helpful for protecting contacts of magnetic switch in case of freuqent operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2280-2282
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• 2005

전기 기기의 스위칭 동작시 발생하는 아크로 인한 화재 및 감전사고가 발생하고 있다. 본 논문에서는 간단한 스위칭 동작을 할 수 있는 회로를 구성하여 아크방전을 시킨 후 고속 카메라를 이용하여 아크 방전의 거동 과정을 분석하였다. 또한, 유한요소해석법으로 전자계 현상을 분석하였다.