• 한국화재소방학회논문지
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• 제18권3호
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• pp.45-50
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• 2004

600V용 비닐절연전선의 절연체로 사용되는 PVC의 열적 열화 특성을 열중량분석과 가속열화시험을 이용하여 연구하였다. TGA를 이용한 활성화에너지는 Kissinger method와 Flynn-Wall-Ozawa method를 이용하여 측정하였다. 활성화에너지를 계산한 결과 600V용 PVC 절연전선은 89.29 kJ/mol～111.39 kJ/mol, 내열 PVC절연전선은 97.80 kJ/mol～119.25 kJ/mol로 나타났다. 또한, 저온인 80, 90, 10$0^{\circ}C$에서 장기가속열화를 통한 활성화에너지를 아레니우스 방정식을 이용하여 계산하였다. 그 결과 PVC 절연전선은 92.16 kJ/mol,내열 PVC절연전선은 97.52kJ/mol로 나타났다. 연구결과에 있어 600V내열 PVC절연 전선이 PVC 절연전선에 비해 활성화에너지가 큼을 알 수 있었으며, 사용 수명을 예측함에 있어서도 장기적으로 안정함을 예측할 수 있다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.489-492
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• 2003

In this paper, we experimented on the deterioration process of power supply cords and analyzed the heating temperature of each part of those cords. We also analyzed the surface states, metallurgical structures surface structures and compositions of the wire melted by over-current. In the results of the analyses, the covering began to be deteriorated from the inside. The heating temperature of extension cord was higher than that of plug body. The dendrite structures appeared at the melted wire. By the SEM and EDS analyses, the dendrite structure showed the growth of copper oxide. We found out the characteristics of PVC insulated flexible cords by over-current from the above experiments and analyses. These results may be useful data in the analyses of deterioration causes of power supply cords.

• 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.

• 한국안전학회지
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• 제34권1호
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• pp.8-13
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• 2019

Weight and elongation changes of IV and HIV insulations were measured simultaneously at several given temperature of $80^{\circ}C$, $90^{\circ}C$ and $100^{\circ}C$. And the lifetime was predicted using the Arrhenius model. Based on the initial weight values, a 50% elongation reduction was seen at 6.96% for the IV insulation and 10.29% for the HIV insulation. The activation energy from the slope of the lifetime regression equation was calculated as 92.895 kJ/mol(0.9632 eV) for the IV insulation and 95.213 kJ/mol(0.9873 eV) for the HIV insulation. Also, the expected lifetime at the operating temperature of $30^{\circ}C$ to $90^{\circ}C$ is 2.02 to 94.32 years, and longer lifetime was predicted on HIV insulated wires than on IV insulated wires. As a result, it was found that the thermal characteristics of the HIV insulated wires were about 12.44% better than those of IV insulated wires under the same conditions of use.

• 한국안전학회지
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• 제23권4호
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• pp.47-52
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• 2008

Many researches on fire risk for normal electric wiring have been pursued in advanced countries such as the USA and Japan, but comparative studies of the partial disconnection and normal state of electric wires have not been conducted. Detection system for the cause of partial disconnection is not developed and prevention countermeasure for electrical fire by the cause is not effective. Therefore, in this paper, partial disconnection characteristics on electric wires were derived and analyzed by experiment and electrical-thermal finite element method(Flux 3D) on the model wires which consist of VCTF(PVC insulated PVC sheathed Cap Tyre Flexible Cord, KS C 3304) and IV(lndoorwire PVC, KS C 3302). VCTF is used in wiring portable electric appliances and the IV is used indoors. Interrelationships between partial disconnection premonitory symptom and current were derived and analyzed by the characteristics based on experiments and thermal analysis for electric wire according to current under normal state and 200% overload state of rated current.

• 한국안전학회지
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• 제19권4호
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• pp.42-47
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• 2004

In this paper, we analyzed on the characteristics of the stranded wire disconnected by repeated stress. The stranded wires that were used in the experiment are PVC insulated flexible cords(VCTFK: Vinyl Insulated Vinyl Cabtyre Cord Flat-type) of $0.75mm^2,\;1.25mm^2,\;and\;2.0mm^2$. They are used to connect the load in low voltage. The stranded wires disconnected by repeated stress were magnified with optical microscope. Using X-ray, the disconnected wire were photo-graphed. we compared mechanical characteristics of the stranded wire between disconnected tendency and allowable current. On the mechanical strength of vinyl cap tire ellipse type cords under bending stress, VCTFK of $1.25mm^2$ was the strongest of them. When it was bent $826.3\pm7$ times, it appeared the disconnected tendency that element wires of VCTFK of $1.25mm^2$ are more about 1.67 times than element wires of VCTFK of $0.75mm^2$. In mechanical strength, VCTFK of $1.25mm^2$ is higher about 1.7 times than VCTFK of $0.75mm^2$. Therefore, we found out that mechanical strength was higher, when the wire had a lot of element wires. In comparison with bending stress, VCTFK of $1.25mm^2$ is the strongest among samples, and it is the most useful in wires of movable type.

• 한국안전학회지
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• 제19권1호
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• pp.60-65
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• 2004

The PVC insulated flexible cords are used mainly as power supply cords of electric appliance. This electric wire is a stranded wire consisted of dozens of strands. In case stranded wires are disconnected by mechanical stress, it weakens electrically. Finally, the over current flows through stranded wires, and electrical fire occurs. In this study, we analyzed the melting properties of strands by over current, such as melting process, melting current and melting time. And we analyzed that quantity of heat for melting, a cross sectional structure, and surface structure by optical microscope and SEM. As analysis results, melting time decreased as melting current increased. And quantity of heat for melting was low, too. From the cross sectional structure of melted wire, when a melting current low and melting time long, it was found that the dendrite structure grew. However, the dendrite structure is hard to grow because growing time is not enough when a melting current high and melting time short.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.464-467
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• 2003

In this paper, we analyzed on the characteristics of the stranded wire disconnected by bending stress. The stranded wire that used in the experiment are PVC insulated flexible cords(VCTFK) of $0.75mm^2,\;1.25mm^2,\;and\;2.0mm^2$. They are used to connect the load in low voltage. The stranded wires disconnected by bending stress were magnified with optical microscope. Using X-ray, the disconnected wire were photographed. we compared mechanical characteristics of the stranded wire between disconnected tendency and allowable current. On the mechanical strength of vinyl captyre ellipse type cords under bending stress, $1.25mm^2$ VCTFK was the strongest of them. When it was bended $826.3{\pm}7\;times$, it appeared the disconnected tendency that element wires of $1.25mm^2$ VCTFK are more about 1.67 times than element wires of $0.75mm^2$ VCTFK. In mechanical strength, $1.25mm^2$ VCTFK is higher about 1.7 times than $0.75mm^2$ VCTFK. Therefore, we found out that mechanical strength will be higher, if element wire is a lot. In comparison with bending stress, $1.25mm^2$ VCTFK is the strongest among samples, and then it is the most useful in wires of movable type.