• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1602-1604
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• 2000

When insulators are operated near cement factories, some amount of cement powder may be stuck on the surface of insulators and decreases their electrical performances. Three kinds of insulators, such as, silicone EPDM and porcelain insulators, are tested in this paper. Testing Voltage of 25kV is applied to the samples, and surface leakage current is measured for 6 months after cement solvent of 10 vol% was stuck on the surface of each insulator in the laboratory. Insulation layers are cut from 3 and 6 month-aged insulators and tested for ac breakdown, impulse breakdown, contact angle. After aging, electrical properties are unchanged in silicone and EPDM insulators but show some changes in porcelain insulators.

• 반도체디스플레이기술학회지
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• 제18권3호
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• pp.47-51
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• 2019

The three different polymer compounds were manufactured with the three different fire retardant (silane coated magnesium dihydroxide) contents, 180, 200, 220 phr, for making cable sheath for ship industry. In the research, ethylene-vinylacetate, polyethylene as matrix polymers and ethylene-vinylacetate grafted maleic anhydride as coupling agent were selected for compounding with fire retardant, closslinking agent, plasticizer, and other additives. In the evaluation. ΔT, Mooney viscosity, and tensile strength increased with the content of fire retardant. But it was found that too much fire retardant damaged aging resistance and cold resistance of the polymer compound.

• 조명전기설비학회논문지
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• 제29권3호
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• pp.88-95
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• 2015

The accelerated thermal aging of CSPE(Chloro Sulfonate Polyethylene) was carried out for 40.41, 121.22, 202.04 days, 16.82, 50.45, 84.09 days and 7.32, 21.96, 36.59 days at 100, 110, and $120^{\circ}C$, respectively, which are equivalent to 20, 60, 100 years of aging at $50^{\circ}C$. The permittivities and the apparent densities of the accelerated thermally aged CSPE samples are increased with accelerated thermal aging year but EAB(Elongation at Break) is decreased with that. The dielectric strength and the electric breakdown of the non-accelerated and accelerated thermally aged CSPE samples do not depend on accelerated thermal aging year and applied voltage rising time. density and EAB measures.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 춘계공동학술발표회요약집
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• pp.323-323
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• 2002

• 대한토목학회논문집
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• 제13권5호
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• pp.85-98
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• 1993

본 논문에서는 재료의 시간의존적 특성에 의한 영향을 고려하며, 재료의 비선형성은 물론 기하학적 비선형성도 고려하여 평면PC사장교의 축방향력과 휨에 의한 극한거동을 해석할 수 있는 비선형 해석방법을 제시했다. 재료의 시간의존적 특성으로는 콘크리트의 크리프, 건조수축과 강도증가, PC 강재와 케이블의 이완을 고려했고 재료의 비선형성으로는 콘크리트의 인장균열과 콘크리트, 철근, PC 강재와 케이블의 비선형 응력-변형도 관계를 고려하고 하중반전에 의한 영향도 고려했다. 기하학적 비선형성으로는 케이블의 색, 구조물의 대변위에 의한 비선형 변위-변형도 관계 및 변형에 따른 구조물의 형상변화를 고려했다. 일반적 형태의 PC 사장교의 해석에 적용하여 PC 사장교의 극한거동 및 재료의 시간의존적 특성이 극한거동에 끼치는 영향을 검토했다.

• 비파괴검사학회지
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• 제22권3호
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• pp.239-245
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• 2002

현재까지 다양한 토목구조물들은 여러 가지 요인에 의한 노후화와 축척된 손상에도 불구하고 별다른 조치 없이 계속해서 사용되고 있었다. 따라서, 이러한 구조물들의 효율적인 유지관리를 유해 계측관리가 중요시되었다. 이에 본 논문에서는 비파괴계측에 의해 사장교의 실시간 계측모니터링시스템을 개발하고자 하며 이를 통해 교량의 안전관리를 하고자 하였다. 계측모니터링시스템은 교량의 유지관리를 도모하고, 교량 관리의 경제적 비용을 줄이게 되며 사장교의 새로운 설계 및 분석방법을 개발하는데 중요한 데이터를 제공할 것이다.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1369-1374
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• 2014

Most accidents of medium-voltage cables installed in nuclear power plants result from the initial defect of internal insulators or the initial failure due to poor construction. However, as the service years of plants increase, the possibility of cable accidents is also rapidly increases. This is primarily caused by electric, mechanical, thermal, and radiation stresses. Recently, much attention is paid to the study of cable diagnoses. To date, partial discharge and Tan${\delta}$ measurements are known as reliable methods to diagnose the aging of medium-voltage cables. High frequency partial discharge measurement techniques have been widely used to diagnose cables in transmission and distribution systems. However, the on-line high frequency partial discharge technique has not been used in the nuclear power plants because of the plant shutdown risk, degraded measurement sensitivity, and application problems. In this paper, the partial discharge measurement with a portable device was tried to evaluate the integrity of the 4.16kV and 13.8kV cable lines. The test results show that the high detection sensitivity can be achieved by the high frequency partial discharge technique. The present technique is highly attractive to diagnose medium voltage cables in nuclear power plants.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권2호
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• pp.45-50
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• 2005

To improve mean-life and reliability of power cable, in this study, we have investigated electrical properties and stress-strain showing by changing the content of carbon black that is semiconductive additives for underground power transmission. Specimens were made of sheet form with the nine of specimens for measurement. Volume resistivity of specimens was measured by volume resistivity meter after 10 minutes in the pre-heated oven of both 25±1 [℃] and 90±1 [℃]. And stress-strain of specimens was measured by TENSOMETER 2000. A speed of measurement was 200[mm/min], ranges of stress and strain were 400[Kgf/㎠] and 600[%]. In addition tests of stress-strain were progressed by aging specimens in air oven. From this experimental results, volume resistivity was high according to increasing the content of carbon black. And yield stress was increased, while strain was decreased according to increasing the content of carbon black. And stress-strain were decreased some after aging because of oxidation reaction of chemical defect. We could know EEA was excellent more than other specimens from above experimental results.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권4호
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• pp.154-160
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• 2005

We have investigated thermal properties showed by changing the content of carbon black which is the component parts of semiconductive shield in underground power transmission cable. Specimens were made of sheet with the nine of those for measurement. Density of specimens was measured by density meter, and then stress-strain of specimens was measured by TENSOMETER 2000. A speed of measurement was 200[mm/min], ranges of stress and strain were 400(Kgf/$cm^2$) and 600[$\%$]. In addition, tests of stress-strain were progressed by aging specimens at air oven. Finally surface profile was shown in order to looking for protrusion of specimens by using smoothness tester. Density was highly measured according to increasing the content of carbon black from this experimental result, and stress was decreased, while strain was increased according to increasing the content of carbon black. And stress-strain were decreased some after aging because of oxidation reaction of chemical defect. Lastly surface of specimens smoothed generally.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.208-211
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• 2003

In this paper, mechanical property of electric epoxy with water aging was discussed. We studied mechanical property of elastic resin after absorption in water from 0 to 484 hour. As a result, diffusion factor of elastic epoxy showed $20-21{\times}10^{-4}mm^2/s$ and general epoxy showed $9.5{\times}10^{-4}mm^2/s$. Elastic property increased linearly according to amount of addictives and decreased elastic property according to amount of water absorption. Tensile strength was reduced to add to addictives. It was effected by water absorption of micro-void of elastic epoxy. Hardness inclined to decrease after increasing according to absorbed time.