• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.08a
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• pp.7-11
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• 2003

for many years already, testing laboratories, research institutes and manufactures try to find a reliable water tree accelerated ageing test that is able to show whether a polymer Medium Voltage cable os susceptible to water treeing or not. Test on laboratory samples, model cable designs, and fell size cable are presented. Apart form aging, another important aspect of any accelerated aging test is the right choice of th preconditioning method. THTS paper is the analysis of weibull distribution method after an accelerated aging test of MV(Medium Cable) cable.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1740-1742
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• 1997

The trend of partial discharges(PD) magnitude which occured in a artificial void at cable joint is investigated as the function of a time. The results have shown that more than 500pC could be sustained for the considerable duration so the efficiency of monitoring a PD magnitude for diagnosing cable joints is confirmed. The other defects at cable joints are now under the same test, we can get the experimental data sooner or later.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1543-1545
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• 1997

In this work, properties of FRP insulation materials by thermal-accelerated degradation were investigated. Usually, most degradations cause the hydrophilic to decrease the contact angle and surface properties. But, in this work on thermal-degradated FRP, we can confirm the introduction of hydrophobic properties by cross-linking and the ablation of small-molecules rather than chain scission and oxidation. Hydrophobic introduction in thermal-degradated FRP caused the increase of electrical insulation on treated FRP surface. But, Tensile strength decreased steeply on FRP being exposed higher temperature.

• Journal of the Korean Society for Railway
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• v.6 no.4
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• pp.265-272
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• 2003

The computer program for the accelerated life testing technique of a machine part under the service conditions is developed under the GUI environment so that the user can easily obtain the results by selecting the program module. Also, the theoretical backgrounds for the computer program and the procedures of the accelerated testing method are introduced by testing the specimens made of the stainless steel 316L under the high temperature and random loading. The reliability of the program is discussed by the experimental results of the fatigue life, age degradation and accelerated testing conditions.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1360-1363
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• 1994

Epoxy resin insulator have good electrical properties (high electric strength, high resistivity, low dielectric loss) in addition to high mechanical strength, small dimensions and design versatility. Polymer insulator, however, are subjected to aging processes, caused by the surrounding atmosphere, which may lead to degradation of their properties. This paper describes the results of a important study on the artificial pollution test, Weather-Ometer properties and rotating wheel dip test of high voltage different aging insulators which are the most important factors for outdoor uses. Also, the objects of this paper are to (a)result of insulator under dry(wet) flashover voltage, (b)artificial pollution test of salt spay, (c)Accelerated aging test of Weather-Ometer, (d) wet and dry flashover voltage under rotating wheel dip test.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1323-1326
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• 1994

the application of epoxy composite materials for outdoor insulating systems has some significant advantages compared with conventional inorganic materials, that is low weight in combination with high mechanical strength, small dimensions and design versatility. The experimental results for the basis composition and interlace characteristics of the matrix resin/inorganic fillers($SiO_2$) which are the composite materials have been studied. The electrical characteristics(electrical breakdown, dielectric, insulating resistivity, tracking) and mechanical characteristics( tensile strength, elongation, flexible strength) in the epoxy composite materials have been studied. The life of the epoxy composite material was evaluated by accelerated Weather-Ometer test and the degradation process due to outdoor exposure condition is discussed with respect to the mechanical and electrical properties.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.279-280
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• 2008

Accelerated aging tests were conducted under laboratory conditions on two generator stator bars. Electrical stress is applied in No. 1 model stator bar. Electrical and thermal stresses are applied in No. 2 model stator bar. As aging times increased from 0 to 4780h, diagnostic tests were performed on No. 1 and No. 2 model stator bars. Diagnostic tests included AC current, dissipation factor(tan$\delta$) and partial discharge magnitude. The ${\Delta}tan{\delta}$ and $\Deta$I of No. 1 and No. 2 model stator bars increased with increased in aging time.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.7
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• pp.1121-1127
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• 1994

The accelerated degradation phenomena in amorphous silicon thin film transistors due to both electrical stress and visible light illumination under the elevated temperature have been investigated systematically as a function of gate bias, light intensity, and stress time. It has been found that, in case of electrical stress, the thrshold voltage shifts of a-Si:H TFT's may be attributed to the defect creation process at the early stage, while the charge trapping phenomena may be dominant when the stressing periods exceed about 2 hours. It has been also observed that the degradation in the device characteristics of a-Si:H TFT's is accelerated due to multiple stress effects, where the defect creation mechanism may be more responsible for the degradation rather than the charge trapping mechanism.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.144-147
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• 2000

The effect of accelerated aging test on ethylene-propylene-diene monomer(EPDM) rubber used for outdoor insulation was studied by X-ray photoelectron spectroscopy(XPS), scanning electron microscope(SEM), FFT spectrum alalysis, and electrical pulse counts using PC by oscilloscope(300 MHz). In electrical alalysis, FFT spectrum analysis indicated arcing caused a significant increase in the third harmonic content of the leakage current of polluted insulator. Also, pulse counts increased as aging time. The surface oxygen and aluminum content were found to increase and that of carbon and nitrogen were found to decrease with time. The detailed XPS analysis indicated that the concentration of carbon in C-C decreased and concentration of highly oxidized carbons increased with time, which was due to the oxidation of EPDM rubber polymer SEM analysis indicated that crack and erosion of EPDM rubber occurred with time.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1460-1462
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• 2003

XLPE compound have used for insulation of 22.9 [kV] power cable. XLPE compound is aged for use long time in distribution line. The cause of aging is water tree is happening and growth. Accelerated water tree test method are Accelerated volatge method and high frequency method. In this paper, high frequency accelerated water tree was performed. And the result was analysed AC breakdown voltage and size and number of water trees.