• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.804-806
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• 1995

This paper discusses Self-organized Distributed Networks(SODN) as identifier of nonlinear dynamical systems. The structure of system identification employs series-parallel model. The identification procedure is based on a discrete-time formulation. The learning with the proposed SODN is fast and precise. Such properties arc caused from the local learning mechanism. Each local networks learns only data in a subregion. Large number of memory requirements and low generalization capability for the untrained region, which are drawbacks of conventional local network learning, are overcomed in the SODN. Through extensive simulation, SODN is shown to be effective for identification of nonlinear dynamical systems.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1120-1125
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• 2004

Welding characteristics of STS304 stainless steel and Inconel 600 using a continuous wave Nd:YAG laser are experimentally investigated. Alloy 600 being used in steam generator tubing of pressurized water reactor(PWR) exposed to some corrosion environment, stress corrosion cracking can occur on this material. Presented here are the results from a series of experiments in which dissimilar metal welds were made using the gas tungsten arc welding process with pure argon shielding gas. But It is well known that solidification cracking susceptibility of austenitic alloys depends on the solidification temperature range and amount/distribution of solute rich liquid that exists at the terminal stages of solidification. An experimental study was conducted to determine effects of welding parameters and to optimize those parameters that have the most influence on eliminating or reducing the extent welding zone formation at dissimilar metal welds.

• 전기학회논문지P
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• 제56권1호
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• pp.37-44
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• 2007

This paper describes characteristics for copper oxide growth of polyvinyl chloride(PVC) insulated wires by series arc. In this experiment, 600V IV wires were used, and characteristics of oxide growth and ignition process were analyzed in case load was 300W, 460W and 600W, respectively. In the result of experiment, covering materials were molten, carbonized and ignited, whereas, oxidized materials were grown in conducting material. During copper oxide was growing, contact voltages and power dissipations increased. When there is copper oxide growth, the waveform of current showed sinusoidal waveform, and the waveform of voltage showed modified waveform. Oxidized materials were heated at about $905^{\circ}C$, surface structure showed irregular shapes, and cross-section showed multiple cracks. And, the results of this experiment were applied to the fire cause analysis of fire evidence collected at the fire scene.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.427-428
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• 2015

본 논문은 DC 배전시스템 내에서 발생할 수 있는 직렬 DC 아크 고장을 검출하기 위한 알고리즘을 제안한다. 직렬 DC 아크 고장은 동일 전위의 도선 또는 접속점의 노화 등으로 인해 발생하며, 아크 고장 에너지의 크기에 따라 수초 이내에 화재 사고를 유발할 수 있기 때문에 정확한 고장 검출을 통한 빠른 제거가 필요하다. 스위칭 전력변환 장치에서 발생하는 노이즈 성분에 의한 검출 알고리즘의 오동작 현상을 제거하기 위해 시간 영역에서의 전류 변화와 주파수 영역에서의 전류 크기 차이를 동시에 이용하여 직렬 DC 아크 고장 발생여부를 검출하게 된다. 제안 알고리즘은 5kW급 용량의 380V 저전압 DC 배전 시스템을 대상으로 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.580-581
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• 2012

아크는 전기화재의 주요 원인 중 하나이며 전기 배선이나 설비 등에서 두 전극 사이의 기체를 통하여 방전되면서 빛과 열을 발산하는 현상이다. 본 논문에서는 UL-1699에서 규정하고 있는 직렬아크의 발생 조건에 따라 모의 아크 발생장치를 통하여 여러 가정용 부하에서 아크를 발생시키고 주파수 영역에서의 아크전류파형을 분석해 보고 신속한 아크 검출 방법을 연구하고자 한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.230-231
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• 2012

This paper describes a gate driver that operates numerous semiconductor switch in the solide-state pulsed power modulator. the proposed gate driver is designed to receive both the isolated drive-power and the on/off pulse signals through the transformer. Moreover, the IGBT-switch can be quickly turned off by adding protection circuit. Therefore it protects the IGBT-switch from the arc condition that frequently occurs in high-voltage pulse application. To comprehend operating characteristic of each IGBT-switch in pulse output condition, the device consisting of a high efficiency soft-switching capacitor charger and two series stacking IGBT-switch is developed. Finally, the relability of the proposed gate driver and the device for its test are proved through PSpice simulation and experiments.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.367-368
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• 2012

AC전원으로부터 DC전압을 얻기 위한 제어정류회로는 신재생에너지의 전력변환장치, UPS, 배터리 충전 장치등 다양한 분야에서 사용되고 있다. 본 논문은 제어정류회로에서 전원측과 부하측에 직렬아크가 발생했을 때 입출력에 미치는 영향을 분석하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.2088-2089
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• 2007

본 논문은 직렬 아크고장 신호분석과 관련된 연구로서, 정상상태와 아크고장 상태에서 발생하는 전압 전류를 검출하여 아크고장 전류의 특이점을 분석하였다. 역률이 1인 저항성 부하와 L성 부하, C성 부하를 구성하고, 순시 임피던스 분석, FFT 분석, 웨이블렛 분석 방법을 사용하였다. 분석결과 순시 임피던스 분석방법과 FFT 분석방법에서는 직렬 아크고장 신호의 특이점을 찾을 수 있었으나 정량화하기가 어렵고, 웨이블렛 분석방법으로는 직렬 아크고장 신호의 특이점 검출 및 정량화 가능성을 발견할 수 있었다.

• Journal of Welding and Joining
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• 제16권1호
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• pp.114-124
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• 1998

The effect of matrix phase (austenite, pearlite, martensite) on the low stress abrasion resistance in the chromium-carbide-type high Cr white iorn hardfacing weld deposites has been investigated. In order to examine matrix phase, a series of alloys with different matrix phase by changing the ratio of Cr/C system by heat treatment were employed. The alloys were deposited twice on a mild steel plate using self-shielding flux cored arc welding process. The low stress abrasion resistance of the alloys against sands was measured by the Dry Sand/Rubber Wheel Abrasion Test(RWAT). Even though formation of pearlite phase in the matrix showed higher hardness than that of austenite, there was no observable difference in wear resistance between the pearlite and austenite phase for the same amount of chromium-carbide in the matrix. On the other hand, the formation of martensitic phase,, from heat treated austenitic alloys (high content of Cr), enhanced wear resistance due to its fine secondary precipitates.

• Journal of Welding and Joining
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• 제16권1호
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• pp.125-133
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• 1998

The effect of volume fraction of Cr carbide phase (Cr CVF) on the low stress abrasion resistance in the chromium-carbide-type high Cr white iron hardfacing weld deposits has been investigated. In order to examine Cr CVF, a series of alloys with varying Cr CVF by changing chromium and carbon contents and the ratio of Cr/C were employed. The alloys were deposited once or twice on a mild steel plate using the self-shielding flux cored arc welding process. The low stress abrasion resistance of the alloys against sands was measured by the Dry Sand/Rubber Wheel Abrasion Test (RWAT). It was shown that hardness and abrasion resistance increased with increasing Cr CVF within the whole test range (Cr CVF : 0.23-0.64). Both primary Cr carbide and eutectic Cr carbide were particularly effective in resisting wear due to their high hardness.