• Title/Summary/Keyword: ageing test

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Ageing Diagnostics in Oil Transformer for Large Capacity due to Test methods (시험방법에 의한 대용량 유입변압기의 열화진단)

  • Sim, Yoon-Tae;Kim, Wang-Gon;Hong, Jin-Woong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07a
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    • pp.96-99
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    • 2003
  • In this paper, ageing diagnostics in the large capacity oil transformer are investigated. Following items are investigated for the ageing diagnostic in transformer oils (leakage current of sensor, power consumption and temperature of transformer oil). All temperature data are gathered from daily report in the substation. The power consumption of transformer are gathered output report of APIS(Airport Power Information System). Especially, data of sensor leakage current are accumulated from the online diagnostic system for transformer oil. The temperature of transformer oils major change factor was ambient temperature and capacity of power load. The leakage current are change by oil temperature. The leakage current ware not more than 2 [nA] in summer,

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Assessment of Seed Viability and Vigour in Neem (Azadirachta indica A. Juss.)

  • Kumar, Devendra
    • Journal of Forest and Environmental Science
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    • v.29 no.4
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    • pp.282-291
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    • 2013
  • Rapid loss in viability of neem (Azadirachta indica A. Juss.) seed is a major problem. Present effort was undertaken for developing a set pattern for assessing of viability and vigour in seed of various mother tree age of neem (Age I-06 years, Age II-15 years, Age III-25 years and Age IV->30 years old). Various viability test viz. triphenyle tetrazolium chloride test, electrical conductivity, excised embryo test, and germination test have been performed on seeds obtained from mother tree age classes. Inconsistency was observed with the TTC and EC test in germination of seed in laboratory as well as nursery. While various vigour tests viz. cold test, chemical stress test (methanol stress test), and accelerated ageing test alongwith ageing index, germination test (G%, MGT and GV) and various seedling growth parameters like seedling length (cm), number of leaves, collar diameter (cm), total biomass (g) alongwith mathematical indices i.e. vigour index, sturdiness quotient, volume index, quality index, root shoot ratio in nursery as well have been taken for study and showed better consistency. On the basis present study results of various viability and vigour test indicated that mother tree age class II performed better in comparison to others and it can be recommended for seed collection. Further it is also recommended that viability of neem seed may be assessed using various laboratory tests like excise embryo test and germination test (G%, MGT and GV) and vigour test may be taken preferably by cold germination test, chemical (methanol) stress test, accelerated ageing test in laboratory and germination alongwith various seedling growth parameters seedling length (cm), number of leaves, collar diameter (cm), total biomass (g) alongwith mathematical indices like Vigour Index, Sturdiness quotient, Volume Index, Quality index, root shoot ratio in nursery as discussed in this study.

Influence of Endurance tests on Space Charge Distribution of 160kV HVDC XLPE Cable

  • Liu, Yun-Peng;Liu, He-Chen
    • Journal of Electrical Engineering and Technology
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    • v.12 no.1
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    • pp.302-309
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    • 2017
  • The ageing of XLPE cable insulation will lead to the accelerating accumulation of space charge, which will greatly affect the safe operation of the HVDC cable. In order to investigate the influence of different ageing modes on the space charge distribution of the HVDC cable, thermal stressed, electrical stressed and electro-thermal stressed endurance tests were carried out on the XLPE peelings. The tested XLPE peelings were obtained from 160kV HVDC cable insulation. The endurance tests were carried at thermal stress of 363K, electrical stress of 20kV/mm DC and a combination of both. The Pulsed Electro-Acoustic (PEA) method was used to measure the space charge distribution of the samples. The influences of ageing on the trap energy distribution were analyzed based on the isothermal relaxation theory and the decay characteristics of the space charge. The results showed that thermal ageing would help to improve the crystalline morphologies of the XLPE at the early stage. The total amount of space charge decreased compared to the ones before thermal ageing. The long term of electrical stress would result in the cleavage of polymer molecule chains which would intensify the accumulation of space charge and increase the density and depth of electron traps. With a combination of electrical and thermal stress, the injection and migration of space charge were more significant. Besides, the depth and density of electron traps increased rapidly with the increase of endurance time.

Ageing Behavior of Beeswax Coated Hanji(I) - Thermal Ageing Test of Beeswax Coated Hanji - (밀랍지의 열화 거동 (제1보) - 열에 의한 밀랍지의 열화 -)

  • Kim, Kang-Jae;Eom, Tae-Jin
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.42 no.2
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    • pp.46-52
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    • 2010
  • The annals of Joseon Dynasty has been known as one of the UNESCO's Memory of the World Heritage. The annals of Joseon Dynasty composed with two kind of books, wax coated book and non coated book. Especially the waxed book have been severely damaged by various reason. For the safety preservation of the annals of Joseon Dynasty waxed book, the thermal ageing mechanism of beeswax coated Hanji paper has been evaluated. The weight loss of waxed Hanji were rapidly increased until 30 days in three temperatures(105, 120 & $150^{\circ}C$) and stabilized after 30 days. The acid value and relative intensity of carbonyl groups in beeswax were increased with strong conditions. This means that the deterioration of beeswax should be progressed with oxidizing reaction. The physical strength and the crystallinity of dewaxed Hanji were decreased with ageing time.

The Analysis of Ageing Characteristics of Insulation Cover Using in Distribution Line (배전용 절연카바류의 경년특성 분석)

  • Kim, D.M.;Song, I.K.;Han, J.H.;Lee, B.S.;Han, Y.H.;Lee, T.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.05c
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    • pp.76-78
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    • 2001
  • In this paper insulation cover that being used in distribution line have been evaluated for aging characteristics. For evaluating its aging properties, we dismounted a variety of samples, like insulation covers for termination of deadend clamp, bushing, LA, COS and sleeve, in the fields. we performed mechanical properties test, electrical test, weathering test, etc. of these samples. And these samples are compared with virgin sample. Test results shows the bad mechanical strength in some part of samples. Especially, Insulation covers for the bushing terminations have cracks in the surface of samples.

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The Comparison of EPDM and Silicone in Housing Materials of Polymeric Suspension Insulators (EPDM 및 실리콘 재질의 폴리머현수애자의 특성 비교)

  • Lee, Byung-Sung;Lee, Jae-Bong;Song, Il-Keun;Han, Sang-Ok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05e
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    • pp.6-10
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    • 2003
  • In our country, the housing materials of polymeric outdoor insulators have mainly been used EPDM or silicone rubber. EPDM housing materials had been widely used in the field for the first time. The reason why silicone has the high cost of production. But recently, most of the manufacturers that newly developed polymeric insulators make its choice of silicone housing. EPDM showed a good resistance to tracking. We compared the various characteristics for EPDM and silicone insulators that have similar type and design. Silicone insulators have more performance in flashover voltage test and leakage current measurement because of a good water repellent than EPDM ones. Also, the property of EPDM compared with silicone insulators greatly decreased after aging test in combined acceleration ageing facilities for 1000 hours.

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Characteristics of Lightning Impulse Current of Zno Block for Transmission Line Arrester with External Gap (송전선로에 사용되는 갭형 피뢰기 소자의 뇌임펄스 전류특성)

  • Cho, Han-Goo;Yoo, Dae-Hoon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.04b
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    • pp.61-62
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    • 2009
  • This paper describes the characteristics of lightning impulse current of ZnO block for transmission line arrester with external gap. The ageing parameters of lightning arresters ate impulse current, moisture ingress, temperature ageing and so on. Especially it is important to estimate the change of electrical characteristics by impulse current. Total energy applied to the ZnO arrester each time is $4/10{\mu}s$, 30kA and $2/20{\mu}s$, 10kA impulse current. Before and After the test, the residual voltage variation of varistors passed was below 5%. According to the test, it is thought that the ZnO arrester shows good stability with impulse current test.

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Characteristics of Lightning Impulse Current of ZnO Block for Transmission Line Arrester with External Gap (송전선로에 사용되는 갭형 피뢰기 소자의 뇌임펄스 전류특성)

  • Cho, Han-Goo;Yoo, Dae-Hoon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.458-459
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    • 2007
  • This paper describes the characteristics of lightning impulse current of ZnO block for transmission line arrester with external gap. The ageing parameters of lightning arresters are impulse current, moisture ingress, temperature ageing and so on. Especially it is important to estimate the change of electrical characteristics by impulse current. Total energy applied to the ZnO arrester each time is $4/10{\mu}s$, 30kA and $2/20{\mu}s$, 10kA impulse current. Before and After the test, the residual voltage variation of varistors passed was below 5%. According to the test, it is thought that the ZnO arrester shows good stability with impulse current test.

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Study on electrical ageing properties of ATV silicone coatings (RTV 실리콘 코팅재의 전기적 열화 특성 연구)

  • Han, Se-Won;Cho, Han-Goo;Han, Dong-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05e
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    • pp.35-39
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    • 2003
  • An ageing characteristics of RTV coating materials by corona discharge have been studied. The recovery of a hydrophobicity of RTV coating materials with the thickness of $300{\mu}m$ was in identical with a bulk silicone materials. The hydrophobicity of RTV coating materials has been almost lost when its were discharged during 40 seconds by corona with 10kV, and recovered after about 45 hours. But the resistivity of RTV coating materials has not been recovered after 45 hours, even though after 80 hours the 95% of initiation resistivity value has been recovered. There was no critical compounds(such as Si and Al) changes on RTV surfaces by the corona discharge treatment until 100 seconds. In the test of arc erosion, it was seen that the coating sample with silicone rubber as a base material have more longer bum-out time than other samples with FRP or glass base.

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TRACKING AND DIELECTRIC CHARACTERISTICS OF OZONE AGED SILICONE RUBBER USED FOR OUTDOOR INSULATI0N (옥외용 실리콘 고무의 장기 오존열화에 따른 내트랙킹 특성 및 유전특성 변화)

  • Lee, C.Y.;Kim, Y.H.;Lee, S.J.;Park, W.K.
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1541-1543
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    • 1996
  • This paper describes the results of characteristics on the tracking resistance, hydrophobicity and dielectric properties of silicone rubbers used for outdoor insulation with ozone ageing. The tracking and ozone ageing tests for this purpose ware made in according to IEC 587 and ASTM D 1149, respectively. Additionally, we investigated the surface structure of the silicone rubbers with FT-IR and SEM. From the test results, it is proven that the higher the degree of ozon ageing, the worse tracking characteristics.

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