• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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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.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.1
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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.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1608-1610
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• 1998

An oil-filled paper-insulated power cable and a XLPE-insulated power cable have been mainly applied as an extra-high-voltage underground power cable. But in recent the XLPE cable has been applied more widely than the OF cable, because of its advantages, such as the low-cost and simple installation. In general two types, molded and prefabricated, of straight joints are applied for the XLPE cables. For a tape-molded joint, one of molded joints, its electrical properties are excellent, but it has some disadvantages, such as a long working time. high skill of workers and the high cost of jointing equipments. For a prefabricated joint, developed and applied in Europe and Japan, its working time is short, its jointing procedures are simple, and its quality control is easy, but its prices are very high. In Korea the development of a compression-type PJ will be finished in the near future, and studies of its jointing techniques and equipments is actively going on. This paper describes the design and construction of the PJ, the jointing procedures and techniques for the PJ, and its future trends.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.103-111
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• 2017

In this study, the thermomechanical stress and fatigue analysis of a high voltage and high current (3,300 V/1200 A) insulated gate bipolar transistor (IGBT) module used for electric locomotive applications were performed under thermal cycling condition. Especially, the reliability of the copper wire and the ribbon wire were compared with that of the conventional aluminum wire. The copper wire showed three times higher stress than the aluminum wire. The ribbon type wire showed a higher stress than the circular type wire, and the copper ribbon wire showed the highest stress. The fatigue analysis results of the chip solder connecting the chip and the direct bond copper (DBC) indicated that the crack of the solder mainly occurred at the outer edge of the solder. In case of the circular wire, cracking of the solder occurred at 35,000 thermal cycles, and the crack area in the copper wire was larger than that of the aluminum wire. On the other hand, when the ribbon wire was used, the crack area was smaller than that of the circular wire. In case of the solder existing between DBC and base plate, the crack growth rate was similar regardless of the material and shape of the wire. However, cracking occurred earlier than chip solder, and more than half of the solder was failed at 40,000 cycles. Therefore, it is expected that the reliability of the solder between DBC and base plate would be worse than the chip solder.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.187-190
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• 2014

An experimental study on downwardly and upwardly spreading flames over slanted electrical wire, which is insulated by Polyethylene(PE), was conducted with applied AC electric field. The result showed that downwardly and upwardly spreading flames with angle of inclination leaned toward burnt side and unburned side, respectively. With applied AC electric fields, size of downwardly spreading flame decreased slightly and that of upwardly spreading flame increased significantly. Flame spread rate showed various trends in terms of inclination, applied voltage and frequency.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.363-365
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• 2014

An experimental study on effect of AC electric field on upwardly spreading flame over electrical wire, which is insulated by Polyethylene(PE), was conducted. The result showed that upwardly spreading flame leaned toward unburned side with angle of inclination. With applied electric field, size of upwardly spreading flame increased significantly. Flame spread rate showed various trends with inclination, applied voltage and frequency.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1897-1899
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• 2004

In this paper, in order to analyze the characteristics of degradation by salt water with insulation cover and OC wire(outdoor cross-linked polyethylene insulated wire) used in power receiving system, an experimental apparatus has been designed and fabricated. An insulation cover and OC wire were installed in an experimental apparatus, and degraded in each case of 2%, 5%, 10% salinity during 12 weeks. An optical microscope was used to observe a changing process of sample surface, and an electrical safety was analyzed by measuring dielectric breakdown voltages of samples. As salinity increased, so ununiformity of sample surface increased. The breakdown wasn't produced to 50kV about samples regardless of salinity, testing period.

• Journal of the Korean Society of Combustion
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• v.19 no.4
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• pp.1-7
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• 2014

An experimental study on downwardly spreading flame over slanted electrical wire, which is insulated by Polyethylene (PE), was conducted with applied AC electric fields. The result showed that the flame spread rate decreased initially with increase in inclination angle of wire and then became nearly constant. The flame shape was modified significantly with applied AC electric field due to the effect of ionic wind. Such a variation in flame spread rate could be explained by a thermal balance mechanism, depending on flame shape and slanted direction of flame. Extinction of the spreading flame was not related to angle of inclination, and was described well by a functional dependency upon the frequency and voltage at extinction.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1630-1632
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• 1999

In this paper, we studied the short circuit current and molten mark of polyvinyl chloride insulated flexible cords(VFF). The calory decreased remarkably with increase of current. The surface structure and composition of a strand wire were analyzed by stereoscope, scanning electron microscope (SEM), and energy dispersive x-ray spectroscopy(EDX). The surface of a strand wire showed columnar and void. The intensity of CuL spectrum increased in melted mark.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1401-1403
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• 1998

The composition, weight decrease, DTA, and surface structure of vinyl insulated wire with thermal treatment conditions have been investigated. The composition of Cu by EDX analysis indicates Cu, Cl, and O lines, and oxidation reaction results from thermal treatment. Thermal treated IV and HIV appeared chemical reaction at $269^{\circ}C$ and $265^{\circ}C$, respectively. SEM of thermal treated Cu at $250^{\circ}C$ disappears an elongation structure, and appears an original structure.