• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.7
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• pp.105-113
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• 2011

The study about three-phase synthetic making test using DC power has been performed in order to increase the making test capacity on Vacuum Circuit Breaker. And, it made possible to solve the limitations that short-circuit testing facilities can not fulfill the testing requirements of VCB exceeding three-phase 36[kV] 31.5[kA]. By using DC power and high speed spark-gap switch, this method made the equivalence with the pre-arc that occurred during the making process under the fault condition of power system. As results, KERI(Korea Electrotechnology Research Institute) could have capacity to carry out type test for VCB under three-phase 52[kV] 40[kV], which satisfies the IEC Standard.

• Journal of Welding and Joining
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• v.15 no.1
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• pp.81-91
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• 1997

In this study, a magnetic sensor to make use of eddy current was developed to detect the weld seam of butt joint in the sheet metal arc welding. This system consist of the sensor device for detecting the weld line, the servo control device for driving the weld torch movement and the control unit. A signal processing was applied to smooth the output signal of the sensor. The weld joint was determined by using a 1st order differential method. To improve tracking accuracy of the system, moving average method which has an effect of proportional and weighted integral control was applied to a series of the weld joint positions obtained above. The weld line for tracking was generated by using data regeneration algorithm. Based on these results, each servo motor was controlled by pulse generator. From experimental results, it was revealed that this system has excellent detecting ability for weld line and seam tracking ability.

• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.318-321
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• 2009

누전차단기 설치 상태에서도 전기화재가 지속적으로 발생함에 따라 전기화재의 원인이 되는 전기 아크에 대한 관심이 증가하고 있는 실정으로 본 논문에서는 UL1699의 아크 저해시험(inhibition tests)에서 제시하고 있는 직렬 아크코장시험(Arc generator test)을 실시하고, 아크고장전류 분석방법으로 최근에 많이 사용되고 있는 이산 웨이블렛 변환을 이용한 3가지 분석방법에 대하여 아크고장전류 검출 확률을 분석하였다. 분석결과, (1) 근사계수 분석에 의한 최대치 변화율 실효치 변화율 분석방법은 46%의 검출 확률을 얻을 수 있었고, (2) 상세계수 분석에 의한 최대치 변화율 실효치 변화율 분석방법은 62%, (3) 근사계수 분석에 의한 잡음량 변화율 shoulder 변화율 분석방법은 100% 검출 확률을 얻을 수 있었다.

• 전기의세계
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• v.21 no.4
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• pp.27-38
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• 1972

This paper discusses the characteristics about the ignition of D.C. main discharge is a plasma jet generator, manufactured for trial as non-transferred type, when the electrical energy appropriate to the ignition is supplied to the gap between the electrodes by using advance discharge of attenuating high frequency voltage generated by a high frequency oscillator with mercury spark gap. These characteristics are under the influences of (a) the length of mercury gap in high frequency oscillator and the quantity of hydrogen flow supplied to it, (b) the condenser capacity of the high frequency oscillator circuit, (c) the length of plasma jet torch in D.C. main discharge circuit and the quantity of argon flow supplied to it, (d) the circuit constants of D.C. main discharge circuit. The results for these characteristics, obtained by this research, are considered to be helpful to the designs for the ignition of a plasma jet as well as the welding arc stabilizer by high frequency discharge and the high frequency arc welder.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.91-93
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• 2008

전기로 인한 화재의 주요원인 중 하나는 전기회로에서 발생되는 아크이며, 기존 사용되고 있는 보호장치인 휴즈나 배선용 차단기가 제공하는 과부하, 누전, 단락뿐만 아니라 아크현상에 대한 보호기능을 갖춘 통합 전기화재 감시 및 보호장치의 필요성과 이에 대한 효율적인 운용시스템이 요구된다. 이처럼 다양한 전기화재 사고 중에서 주요 사고 사례 중의 하나가 선로 혹은 전선의 절열 파괴로 일어나는 직렬아크, 스파크(series arc, spark) 현상(누전차단기 혹은 과전류차단기가 동작하지 않는 범위의 아크사고 모의)이다. 이러한 사고를 모의하기 위한 아크발생장치를 설계하여 UL-1699에서 규정하는 아크의 발생여부를 확인할 수 있다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.4
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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].

• Journal of Electrical Engineering and Technology
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• v.7 no.3
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• pp.389-395
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• 2012

In this paper, we analyzed the frequency spectrum of the electromagnetic waves radiated by an electric discharge as a basic study to develop an on-line diagnostic technique for power equipment installed inside closed-switchboards. In order to simulate local and series arc discharges caused by an electric field concentration and poor connections, three types of electrode systems were fabricated, consisting of needle and plane electrodes and an arc generator meeting the specifications of UL 1699. The experiment was carried out in an electromagnetic anechoic chamber, and the measurement system consisted of a PD free transformer, a loop antenna with a frequency bandwidth of 150 kHz-30 MHz, an ultra log periodic antenna with a frequency bandwidth of 30 MHz-2 GHz, and an EMI test receiver with a frequency bandwidth of 3 Hz-3 GHz. According to the experimental results, the frequency spectra of the electrical discharges were widely distributed across a range of 150 kHz-400 MHz, depending on the defects, while commonly found between 150 kHz and 10 MHz. Therefore, considering the ambient noise and antenna characteristics, the best frequency bandwidth for a measurement system to monitor abnormal conditions by detecting electromagnetic waves in closedswitchboards is 150 kHz-10 MHz.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1800-1803
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• 2002

The pulsed power system was widely making use good of many industrial and environments. The pulse generator generally required for short pulse duration and high peak value was forced to consider its volume and economy. In this paper, this system is designed and fabricated which has a compact size of pulse generator with switched MOSFET. We have studied the removal of rust material using Arc discharging in pulsed power system. It have tested their characteristics by adjusting variable voltage charging and pulse repetition rate. As a result, We can eliminate rust materials with this device.

• 전기의세계
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• v.25 no.2
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• pp.55-57
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• 1976

자동차에서 발전기는 engine의 기계적 energy를 전기 energy로 변환시켜 engine의 발동, light, radio및 여러가지 계기등에 전류를 공급하며 잉여전력을 축전지에 저장한다. 이러한 자동차용 발전기는 1900년 중반기까지 직류발전기를 사용하였으나 1960년 초기부터 반도체개발과 더불어 저속출력특성이 우수한 교류발전기와 정류기를 병용하였다. 그러나 1960년 하반기부터는 자동차의 고속화, 차내의 라디오, TV시설, 각종 전자제어장치등의 급속한 발달로 보다 안정도가 높은 전원의 공급이 필요하게 되었다. 또한 자동차사용이 일반화됨에 따라 최소의 유지보수를 요하는 발전기를 추구하게 되었다. 이에 따라 미국, 영국, 불란서 등 선진공업국에서는 브러시가 필요없는 발전기의 개발을 서두르게 되었으며 여러가지 형태의 Brushless generator를 개발하여 현재 사용하고 있다. 종래의 발전기에서 Brush와 slip-ring, 즉 금속의 회전마찰접촉을 통하여 계자권선에 전류가 공급됨으로 이에 따른 성능저하, 접촉부분에서 발생하는 arc로 인한 폭발위험 및 전자장치에 주는 방해, Brush 마모로 인한 유지보수등의 단점을 주고 있다.

• The KIPS Transactions:PartD
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• v.11D no.7 s.96
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• pp.1427-1434
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• 2004

Database system benchmarks, which are usually evaluated to use the maximized resource in order to get the best results, arc not likely to simulate the real environment. We propose a workload generator that helps benchmarks be executed in the environment similar to a real world. The workload generator can create memory-bound, CPU-bound, and I/O-bound workloads. The workload generator allows users to create an integrated workload. which is similar to a real workload users run across in practice. Finally, we conducted the experiments that the Wisconsin benchmark was performed with the TPC-C and with the workload generation tool, and showed the feasibility of the proposed workload gen-eration tool comparing with two experimental results.