• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.3
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• pp.37-46
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• 2002

• Fire Science and Engineering
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• v.31 no.1
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• pp.42-49
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• 2017

The present article reports the tracking characteristics of phenolic resin insulation material due to accelerated degradation. For assessing insulation degradation of the phenolic resin insulation material, experiment samples with equivalent years of 0, 10, 20, 30, and 40 years were produced by conducting accelerated degradation experiments using Arrhenius equation. Subsequently, tracking experiments according to KS C IEC 60112 standard were conducted for the experiment samples that were previously subjected to accelerated degradation. According to the measured results for tracking characteristics of phenolic resin subjected to accelerated degradation, upon dropping of 0.1% ammonium chloride, the risks were shown to increase by 1.38 times for the equivalent life of 10 years; 1.45 times for 20 years; 1.62 times for 30 years; and 1.94 times for 40 years based on the equivalent life of 0 year. Upon dropping of 0.01% ammonium chloride, the risks were shown to increase by 1.39 times for the equivalent life of 10 years; 1.52 times for 20 years; 1.99 times for 30 years; and 5.30 times for 40 years. According to the experimental results, the tracking risk was shown to be higher for longer-duration insulation degradation due to aging. In particular, the risk was observed to be greatly increased in the case of the equivalent life of 40 years. Therefore, it is proposed that the occurrence possibility and the risk of electric fires could be minimized through institutional preparation of recommended replacement period by considering risks such as insulation degradation, etc. due to aging.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.14-18
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• 2018

Generally. the Ohmic's law is an important factor to increase the conductivity in a micro device. So it is also known that the Ohmic contact in a semiconductor device is import. The PN junction as a structure of semiconductor involves the depletion layer, and this depletion layer induces the non linear electrical properties and also makes the Schottky contact as an intrinsic characteristics of semiconductor. To research the conduction effect of insulators in the semiconductor device, $SiO_2$ thin film and $V_2O_5/SiO_2$ thin film were researched by using the current-voltage system. In the nano electro-magnetic system, the $SiO_2$ thin film as a insulator had the non linear Schottky contact, and the as deposited $V_2O_5$ thin film had the linear Ohmic contact owing to the $SiO_2$ thin film with superior insulator's properties, which decreases the leakage current. In the positive voltage, the capacitance of $SiO_2$ thin film was very low, but that of $V_2O_5$ thin film increased with increasing the voltage. In the normal electric field system, it was confirmed that the conductivity of $V_2O_5$ thin film was increased by the effect of $SiO_2$ thin film. It was confirmed that the Schottky contact of semiconductors enhanced the performance of electrical properties to increased the conductivity.

• Fire Science and Engineering
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• v.31 no.6
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• pp.91-98
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• 2017

The present paper is a study on the tracking characteristics depending on accelerated degradation of PVC insulation material. In order to insulation degradation of PVC insulation material, the Arrhenius equation, a type of accelerated degradation test formula, was used to conduct accelerated degradation experiments with experiment samples prepared at the following age equivalents: 0, 10, 20, 30 and 40 years. Afterwards, a tracking experiment was conducted on the accelerated experiment samples as part of the KS C IEC 60112 criteria. When measuring the PVC tracking features according to the accelerated aging, the results showed that when 0.1% of ammonium chloride was added to the PVC insulating material, but no tracking occurred. However, depending on the age equivalent, The results of analyzing the current waveform and voltage waveform of the tracking propagation process showed the age equivalent from 0 years to 40 years displayed a break down in insulation resistance and even the BDB(before dielectric breakdown) sections did not maintain the same functionality of the original material. Based on a criterion of an age equivalent of 0 years, material with an age equivalent of 10 years posed a 1.4 times greater risk, material with an age equivalent of 20 years posed a 2 times greater risk, material with an age equivalent of 30 years posed a 4.6 times greater risk, and material with an age equivalent of 40 years posed a 7 times greater risk.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.161-167
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• 2009

Organic insulating materials which are utilized as insulating materials for the low voltage show unique carbonization characteristics when they are carbonized by a leakage current. Therefore the use of the carbonization characteristics makes it possible to examine the electrical fire which is caused by a leakage current flowing on the surface of the organic insulating material. In order to understand such carbonization characteristics, in this paper, experiments have been done to carbonize typical organic insulating materials such as phenol resin, PVC, and acrylic resin, and the carbonization patterns and the IR absorption spectrum of specimens have been analyzed. According to the analysis of the carbonization patterns, the phenol resin shows the so-called 'spider-leg' carbonization pattern due to a thermosetting property. In contrast to the phenol resin, the thermoplastic property makes it difficult to observe a clear carbonization pattern to verify carbonizing causes on the surfaces of PVC and acrylic resins. In this case, the IR absorption spectrum can be analyzed to examine the specimen carbonized by a leakage current. The analysis result shows that absorption peaks appear at the wave numbers of $3,400[cm^{-1}]$ and $1,618[cm^{-1}]$, which can be an important factor to verify the carbonizing causes.

• Fire Science and Engineering
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• v.32 no.6
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• pp.1-6
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• 2018

This study is to analyze the characteristics of the yellow insulation ring type of the CSST used for tubing when it is artificially deteriorated and damaged by burning. The CSST for tubing consists of a tube, protective coating, nut, yellow insulation ring, packing, and socket. In addition, it is thought that a yellow insulation ring and rubber packing were used to connect the tube and socket in order to improve the airtightness and insulation performance. The result of the verification of the data acquired from the tests in the 95% confidence interval shows that the Anderson-Darling (AD) and P value were analyzed to be 0.945 and 0.015, respectively. This confirms that the test data of the CSST for tubing is reliable. The analysis of the arithmetic mean of the insulation resistance of a CSST showed that the CSST damaged by burning by a torch, and the one damaged by electrical burning, was $16.7k{\Omega}$ (the greatest relatively) and $208{\Omega}$ (the lowest), respectively, while it was $1.72k{\Omega}$ in the case of a normal product. Therefore, the analysis result of the insulation resistance of the CSST collected from the scene of a fire can be utilized to examine the cause of damage by burning. In addition, it was found that when the maximum current of 97 A was applied to the CSST for about 5 s using a Primary Current Injection Test System (PCITS) the protective film and insulation ring of the CSST has no difference from that of a normal product. However, a part of the metal tube was melted.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1664-1666
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• 2004

This paper describes the use of Armaid papers and varnishes in electric motors. We compare with boundary element method(BEM) and finite element method(FEM) by calculated electric field strength. Several computer software package to perform such calculations based on electrostatic field and applicable DC are available.

• Progress in Superconductivity and Cryogenics
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• v.6 no.1
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• pp.48-52
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• 2004

Breakdown characteristics of insulator-liquid nitrogen ($LN_2$) composite insulation for resistor type High $T_c$/ superconducting fault current limiter (HTSFCL) under ac and impulse voltage in $LN_2$ has been studied using model electrode systems. Electrodes for model electrode systems were made of SUS 304 contacted fiberglass reinforced plastic (FRP) and Au coated sapphire. The breakdown characteristics of model electrode systems were investigated experimentally for FRP thickness ranging from 1 mm to 5 mm. surface distance ranging from 2.5 mm to 7 mm and electrode gap ranging from 1 to 5 mm. The experimental data suggested that the breakdown voltage of model electrode systems in $LN_2$ is highly dependent on the surface distance, electrode gap as well as on the FRP thickness. Also, we had observed discharge traces and puncture due to high-voltage 60-Hz AC stress.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1601-1602
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• 2011

전 세계적으로 매년 증가하고 있는 전력수요는 높은 부하밀도와 함께 송전계통의 대용량화를 필요로 하고 있다. 단순히 송전회전의 증가를 통한 송전계통의 대용량화는 비용의 증가를 초래하며, 과밀화된 도심에서의 경과지 확보와 환경적인 악영향에 대한 우려 등으로 어려움에 직면하고 있다. 따라서, 높은 부하밀도의 수용가가 집중된 송전계통의 대용량화는 보다 적은 비용과 환경적 영향을 고려하여 지중송전 케이블의 적용이 필요하며, 이러한 특수목적의 송전을 위하여 고효율, 대용량화의 여러 기술이 연구 개발되어 적용 중이며, 일부 기술은 상용화 단계에 있다. 본 논문은 지중송전 케이블의 대용량화 기술 중에 도체의 교류저항을 저감하여 저손실과 대용량 송전이 가능한 소선절연도체(Conductor with insulated wires 또는 Enamelled wires)의 개발과 설치공사에 대하여 기술하고자 한다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1688-1693
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• 2016

In this study shall investigate the influence upon the electrical property of transformer oil due to the heat among accelerated heat degradation experiment for a constant hour in the typical insulation oils of mineral base oil, silicon base oil and vegetable oil. In addition, the electric insulation performance of insulation materials in transformer shall be evaluated through the electric property analysis according to the heat degradation of epoxy insulation material, which has been used for electric facilities such as a molded transformer.