• Title, Summary, Keyword: Accelerated thermal aging

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Accelerated Thermal Aging Measurement and Analysis of CSPE Cable for Condition Monitoring (CSPE 케이블의 상태감시를 위한 가속열화 측정 분석)

  • Park, Joung-Ho;Cha, Wang-Cheol;Lee, Jung-Hoon;Cho, Uk-Rae;Kim, Jae-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.3
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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.

A Study on Validation of Condition Monitering Method of Accelerated Thermal Aging CSPE (가속열화 된 CSPE 상태감시법의 유효성 연구)

  • Shin, Yong-Deok;Goo, Cheol-Soo;Kim, In-Yong;Lee, Jung-Hoon
    • Proceedings of the KIEE Conference
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    • pp.1447-1448
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    • 2011
  • The CSPE cables are used for three years in nuclear power plant. The accelerated thermal aging of chloro sulfonate polyethylene(CSPE) jacket of test cables were carried out for the period equal to 10, 20 and 30 years in air at 90 and $100^{\circ}C$, respectively. The electrical volume resistivity, density, XPS, FE-SEM, EDS and XRF of the accelerated thermal aging of CSPE were measured. The validation of condition monitering method of accelerated thermal aging CSPE was estimated by them. The best validation of condition monitoring method of accelerated aging CSPE is electrical volume resistivity because change thermal of the specimen showed distinction.

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Analyses on Electrical-Mechanical Characteristics of Environment-friendly Transformer Insulating Material by Accelerated Thermal Aging (가속 열 열화에 따른 환경친화형 변압기 절연물의 전기적-기계적 특성 분석)

  • Shim, Myeong-Seop;An, Jung-Sik;Choi, Sun-Ho;Jeong, Jung-Il;Lee, Tae-Ho;Huh, Chang-Su
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.10
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    • pp.1832-1838
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    • 2010
  • Aging of transformer insulating material in natural ester insulating oil is compared to that in conventional transformer oil. Aging of insulating paper and insulating oil have been studied by performing accelerated thermal aging test. Sealed aging test vessels containing cooper, laminated core, Kraft paper and insulating oil(natural oil or mineral oil) were aged at $140^{\circ}C$ for 500, 1000, 1500 and 2000 hours. Insulating oils after aging are investigated with total acid number, breakdown voltage and viscosity. Also, degradation of insulating paper after aging is determined using breakdown voltage and mechanical strength. Accelerated aging studies demonstrate a slower aging rate for natural ester insulating oil compared to the rate for conventional mineral oil.

A Study on Practicality of Condition Monitoring Method of Accelerated Thermal Aging CSPE (가속열화 된 CSPE 상태감시법 유효성 평가)

  • Lee, Jung-Hoon;Goo, Cheol-Soo;Kim, In-Yong;Shin, Yong-Deok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.11
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    • pp.2088-2092
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    • 2011
  • The accelerated thermal aging of CSPE(chloro sulfonate polyethylene) of test cables were carried out for the period equal to 10, 20 and 30 years in air at $100^{\circ}C$, respectively. The CSPE cables(TAIHAN electric wire Co. Ltd) which installed in nuclear power plant for three years were used as starting materials. Condition monitering methods of the accelerated thermal aging of CSPE cables were estimated through indenter modulus and OIT(oxidation induction time) of IEC 62582, and those were newly estimated through volume electrical resistivity, ultrasound reflection time, density, FE-SEM(field emission scanning electron microscopy), XPS(x-ray photoelectron spectroscopy), EDS(energy dispersive spectroscopy), and WD-XRF(wavelength dispersive x-ray fluorescence). A new condition monitoring methods of the accelerated thermal aging of CSPE cables were generally coincident with trend of indenter modulus expect EDS, XPS and XRF. A volume electrical resistivity among new condition monitoring methods of the accelerated thermal aging of CSPE cables is excellent. It is considered that life-time of CSPE cable can be predicted through volume electrical resistivity, if CSPE jacket was aged for period such as more than 20 years.

Properties of Thermal Performance on Stator Coil of Traction Motor by Accelerated Test (견인전동기 고정자 코일의 열적 열화특성)

  • Park Hyun-June;Lee Chang-Moo;Lee Han-Min;Jang Dong-Uk
    • Proceedings of the KSR Conference
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    • pp.606-610
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    • 2003
  • The 200 class insulation system which adopted to traction motor have excellent dielectric strength but weaken to thermal stress therefore deterioration phenomena analysis according to thermal stress is necessary. Accelerated thermal aging tests have been used to determine thermal reliability of stator coils used as traction motor in electric multiple unit. The conventional aging test is carried on according to IEC 60034-18-31 and IEEE Std. 275-1992. Variation in insulation resistance, P.I, capacitance, dielectric loss($tan{\delta}$) and partial discharge are measured during the aging cycle. Sample coils for traction motor were tested by accelerated aging test which composed of heat, vibration and moisture. Reliability and expected life were evaluated on the insulation system for traction motor.

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Effects of Accelerated Iso-Thermal Aging on Elastic-Plastic Fracture Toughness and Fracture Resistance Curve by Unloading Compliance Method in SA533B Low Alloy Steel (제하 컴플라이언스법에 의한 SA533B강의 $J_1C$ 및 J-R 곡선에 미치는 열시효 영향)

  • 윤한기;차귀준
    • Journal of Ocean Engineering and Technology
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    • v.8 no.2
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    • pp.157-165
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    • 1994
  • Effect of an accelerated iso-thermal aging (375 degree C x 66days, 375 degree C x 200days) on elastic-plastic fracture resistance curve were examined in SA533B low alloy steel. Fracture toughness test are conducted by unloading compliance method at room temperature. But the apparent negative crack growth phenomenon, usually arise in partial unloading compliance test. The phenomenon of negative crack growth may be eliminated by the offset technique. There is no effect of aging on J sub(IC) and dJ/da in iso-thermal aged (375 degree C x 66 days) specimen, but there is very little effect in iso-thermal aged (375 degree C x 200 days) specimen.

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Accelerated Aging Characteristics of Electroconductive Paper (탄소섬유를 첨가한 전도성 종이의 강제열화 특성)

  • Kim, Bong-Yong
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.43 no.2
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    • pp.24-30
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    • 2011
  • The accelerated aging characteristics of electroconductive papers manufactured with a mixture of carbon fiber were investigated by heating in dry oven. By accelerated aging time, the tensile strength, tensile stretch of the papers were decreased more slowly with increase of carbon fiber content, but the electrical conductivity was more rapidly decreased in case of high carbon fiber content. The weight loss of papers by thermal analysis were reduced as increasing the carbon fiber content. These results were indicated that the electrical conductivity of carbon fiber was diminished easily by heat aging, but thermal characteristic of carbon fiber was much better than that of wood pulp.

Aging Characteristics of Glass Fabric/Phenolic Composites for Tilting Train Using Accelerated Aging Tester (가속노화시험장치를 적용한 틸팅열차용 유리섬유직물/페놀릭 복합재의 노화특성 평가)

  • Yoon Sung-Ho;Nam Jung-Pyo;Hwang Young-Eun;Lee Sang-Jin;Shin Kwang-Bok
    • Journal of the Korean Society for Railway
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    • v.8 no.2
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    • pp.188-194
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    • 2005
  • Aging characteristics of glass fabric/phenolic composites for tilting train subjected to combined environmental aging factors were investigated. A 2.5KW accelerated aging tester with a xenon-arc lamp was used to provide environmental aging factors such as temperature, moisture, and ultraviolet. A series of aging tests were conducted up to 3000 hours and several types of specimens were prepared along the warp direction and the fill direction. Mechanical degradations for tensile, flexural, and shear properties were evaluated as a function of exposure times through a material testing system. Thermal analysis properties such as storage shear modulus, loss shear modulus, and tan 3 were measured through a dynamic mechanical analyzer. Finally exposed surfaces of the composites were examined using a scanning electron microscope. According to the experimental results, mechanical properties and thermal analysis properties of glass fabric/phenolic composites were found to be slightly degraded as a function of exposure times due to combined environmental effects.

Analysis of Insulation Aging Mechanism in Generator Stator Windings (발전기 고정자 권선의 절연열화 메카니즘 분석)

  • 김희동
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.2
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    • pp.119-126
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    • 2002
  • The mica/epoxy composite used in generator(rated 22 kV and 500 MW) stator windings was aged at 180$\^{C}$ for up to 1000 hours in air and hydrogen. The degradation mechanism was investigated through the defect of evolution and microstructural analysis by performing SEM(Scanning Electron Microscope). As the thermal aging time increases, the number of voids per unit volume increases at the mica/epoxy interface of generator stator windings. The aged specimens in hydrogen showed retarded generation and growth of voids. Accelerated aging tests were conducted using the combination of thermal and electrical aging in air and hydrogen. The aging was carried out at a combined stress such as thermal aging at 110$\^{C}$, electrical aging at 5.5 kV/mm and frequencies 420 Hz in air, and electrical aging at 5.5 kV/mm and frequencies 420 Hz in hydrogen (pressure 4 kg/㎠). Thermal and electrical aging generates large voids at the mica/epoxy interface in air. Electrical aging in hydrogen also generates small voids, delaminations and cracks in mica tapes.

Evaluation of Mechanical Properties with Thermal Aging in CF8M/SA508 Welds (CF8M과 SA508 용접재의 열화거동과 기계적특성 평가)

  • 우승완;최영환;권재도
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.12
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    • pp.1968-1973
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    • 2004
  • Structural degradations are often experienced on the components of nuclear power plants in reactor pressure vessels (RPV) and steam generators (SG) when these components are exposed to high temperature and high pressure for a long period of time. Such conditions result in the change of microstructures and of mechanical properties of materials, which requires an evaluation of the safeguards related to structural integrity. In a primary reactor cooling system (RCS), a dissimilar weld zone exists between cast stainless steel (CF8M) in a pipe and low-alloy steel (SA508 cl.3) in a nozzle. Thermal aging is observed in CF8M as the RCS is exposed for a long period of time under the operating temperature between 290 and 33$0^{\circ}C$. Under the same conditions, it is well known that degradation is not observed in low alloy steel. An investigation of the effect of thermal aging on the various mechanical properties of the dissimilar weld zone is required. The purpose of the present investigation is to find the effect of thermal aging on the dissimilar weld zone. The specimens are prepared by an artificially accelerated aging technique maintained for various times at 43$0^{\circ}C$, respectively. Then, The various mechanical test for the dissimilar welds are performed.