• Title/Summary/Keyword: Transformer oil

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Gas Detector for Hydrogen Dissolved in Transformer Oil

  • Seo Ho-Joon;Hwang Kyu-Hyun;Rhie Dong-Hee
    • KIEE International Transactions on Electrophysics and Applications
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    • v.5C no.2
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    • pp.72-75
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    • 2005
  • In oil-filled equipment such as transformers, partial discharge or local overheating will precede a final shutdown. Accompanied with such problems is a decomposition of insulating material into gases, which are dissolved into the transformer oil. The gases dissolved in oil can be separated with some membranes based on the differences in permeability of membranes to different gases. This paper discuss the permeability characteristics of several membranes for separation hydrogen gas in oil. With result of this paper, it may become possible to detect fault-related gases from transformer oil and predict incipient failures in the

Evaluation of Thermal Behavior of Oil-based $Al_2O_3$ Nanofluids (오일 기지 알루미나 나노유체의 열적거동 평가)

  • Choi, Cheol;Yoo, Hyun-Sung;Oh, Je-Myung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.176-177
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    • 2006
  • Two kinds of alumina nanofluids are prepared by dispersing $Al_2O_3$ nanoparticles m transformer oil. The thermal conductivity of the nanoparticle-oil mixtures increases with particle volume fraction and thermal conductivity of the solid particle itself. The $Al_2O_3$ nanoparticles at a volume of 0.5% can increase the thermal conductivity of the transformer oil by 5.7%, and the overall heat transfer coefficient by 20%. From the natural convection test using a prototype transformer, the cooling effect of $Al_2O_3$-oil nanofluids on the heating element and oil itself is confirmed. However, excessive quantities of the surfactant have a harmful effect on viscosity, and thus it is strongly recommended to control the addition of the surfactant with great care.

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Electrical Breakdown Properties of Insulating Oils for oil-immersed transformer (유입변압기용 절연유의 절연파괴특성)

  • Lee, I.S.;Shin, H.T.;Lee, J.P.;Lee, S.W.;Hong, J.W.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.605-608
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    • 2001
  • With the intention of investigating the breakdown properties of oil-immersed transformer oils in temperature range of $20\sim100[^{\circ}C]$, we are made researches AC breakdown in the gap of $500\sim2500[{\mu}m]$. The classification for the physical properties of oil for oil-immersed transformer by FTIR and H-NMR experiments was confirmed to type of mineral oils. As the dependance of breakdown properties due to electrode gap length variation, breakdown voltage was found increasing according to the increase of gap, while dielectric strength was decreasing. As a result the characteristics for AC breakdown, It goes to prove that the breakdown voltage was increased to $90[^{\circ}C]$ but decreased over $90[^{\circ}C]$ in the temperature range. Also, breakdown voltage was found increasing in the increase of gap and the rising of temperature according to Weibull distribution.

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Evaluation of Thermal Behavior of Oil-based Nanofluids using Ceramic Nanoparticles (세라믹 분말을 이용한 오일 기지 나노유체의 열적거동 평가)

  • Choi, Cheol;Yoo, Hyun-Sung;Oh, Je-Myung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.7
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    • pp.587-593
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    • 2007
  • Oil-based nanofluids were prepared by dispersing spherical and fiber shaped $Al_2O_3$ and AlN nanoparticles in transformer oil. Two hydrophobic surface modification processes using oleic acid (OA) and polyoxyethylene alkyl acid ester (PAAE) were compared in this study. The dispersion stability, viscosity and breakdown voltage of the nanofluids were also characterized. $(Al_2O_3+AlN)$ mixed nanofluid was prepared to take an advantage of the excellent thermal conductivity of AlN and a good convective heat transfer property of fiber shaped $Al_2O_3$. For $(Al_2O_3+AlN)$ particles with 1 % volume fraction in oil, the enhancement of thermal conductivity and convective heat transfer coefficient was nearly 11 % and 30 %, respectively, compared to pure transformer oil. The nanofluid, containing $Al_2O_3+AlN$, successfully lowered the temperature of the heating element and oil itself during a natural convection test using a prototype transformer.

Analysis on the Chemical and Electrical Characteristic of Vegetable oil by Accelerated Aging (가속열화에 따른 식물성절연유의 화학적.전기적 특성 분석)

  • Choi, Sun-Ho;Jeong, Jung-Il;Huh, Chang-Su
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.5
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    • pp.984-989
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    • 2011
  • Electrical insulation is one of the most important part in a high voltage apparatus. Recently, researchers are interested in the environmental friendly vegetable oil from environmental viewpoint. Accelerated aging transformer insulating material in vegetable oil was compared to that of mineral oil. Accelerated aging oil samples produced in the oven at $140^{\circ}C$ for 500, 1000, 1500, 2000hours. And Real transformer insulation oils samples of vegetable oil and mineral oil were aged by thermal cycles repeating from $30^{\circ}C$ to $120^{\circ}C$. Samples were analyzed at 42, 63, 93, 143, 190, 240, 300 cycles. The mineral and vegetable insulating oils were investigated for breakdown voltage, water content, total acid number, viscosity, volume resistivity, insulating paper and oil permittivity, and dissolved gas analyses. The breakdown voltage of the vegetable insulating oil is higher than that found for the mineral oil; the accelerated aging progress decreased the breakdown voltage. The vegetable oil had a higher water saturation than the mineral oil; the vegetable oil has the superior water characteristics and breakdown voltage. And high viscosity of vegetable oil, care has to be taken, especially when designing the cooling system for a large transformer.

Chemical Dechlorination Process of PCBs in Industrial Transformer Oil: Approach to Practical Use (변압기 오일 내 PCBs의 화학적 탈염소공정: 실용적인 접근)

  • Ryoo, Keon-Sang;Byun, Sang-Hyuk;Choi, Jong-Ha
    • Journal of Environmental Science International
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    • v.18 no.9
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    • pp.953-959
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    • 2009
  • A practical and efficient disposal method for chemical dechlorination of PCBs (polychlorinated biphenyls) in transformer oil was evaluated. The transformer oil containing PCBs was treated by the PEG 600 (polyethylene glycol 600) and potassium hydroxide (KOH) along with different reaction temperatures(25, 50, 100 and $150^{\circ}C$) and times(30, 60, 240 and 480 min). The best disposal efficiency of PCBs in transformer oil was attained under the experimental conditions of PEG 600 (2.5 w/w%)/KOH (2.5 w/w%)/$150^{\circ}C$/4 hrs, showing completely removal of all PCBs containing 3-9 chlorines on two rings of biphenyl. In studying the reaction of PEG/KOH with PCBs, it confirmed that the process led to less chlorinated PCBs through a stepwise process with the successive elimination of chlorines.

Assessing the Life of the Oil-filled Transformer (유입전력용 변압기의 수명평가 기술)

  • Park, Hyun-Joo;Nam, Chang-Hyun;Yoon, Yeo-Chan
    • Proceedings of the KIEE Conference
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    • 2006.07a
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    • pp.498-499
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    • 2006
  • Oil-filled transformer technology has been around more than 100 years. The principle of operation in the same today as it has been for the previous decades. But all transformers have their life so it is important to know their useful life and the time for replacement. This paper will address this issue and provide the distribution transformer oil aging test results. Distribution transformer and laboratory specimens were externally heated to their respective maximum temperatures. Sample of oil and paper were removed at convenient intervals for testing. We believe that the results of this study will show the possibility of assessing the life of transformers.

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Adsorption of PCBs in Transformer Oil on Powder Activated Carbon and Synthetic Zeolite (활성탄과 합성 제올라이트를 이용한 폐절연유 내 PCBs 흡착)

  • Chu, Heon-Jik;Choi, Sung-Woo
    • Journal of Environmental Science International
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    • v.21 no.5
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    • pp.573-578
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    • 2012
  • In this study, adsorption of polychlorinated biphenyls(PCBs) in transformer oil on powder activated carbon (PAC) and synthetic zeolite was evaluated. Adsorption characteristics of PCBs on the PAC and zeolite has been investigated in a batch system with respect to adsorbents amount and contact time. BET results showed 908 m2/g for PAC and 483 m2/g for zeolite. The adsorption capacity of PCBs increased with an increasing input amount of absorbent. The adsorption experimental results showed that PAC removed 90% of input PCBs in transformer oil while zeolite removed only 64%. Adsorption of PCBs to PAC and zeolite fit the Freundlich model well. The Freundlich parameter, Kf, for PAC and zeolite was 193.1 and 43.0 respectively, indicating that PAC is effect adsorbent for PCBs adsorption in transformer oil.

The Characteristics of Volume Resistivity for the Transformer Oil irradiated with the Electron Beam of Low Dose (저조사량 전자선에 대한 변압기유의 체적고유저항 특성)

  • 이용우;이우영;조돈찬;김왕곤;홍진웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.05a
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    • pp.211-215
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    • 1996
  • In this paper, the volume resistivity of transformer oil is made researches so that the electrical properties for transformer oil is investigated. The specimen is produced by the irradiation of electron beam classified into the low dose, such as 0.5[Mrad], 1[Mrad], 2[Mrad]. The effect of electron team irradiation is studied by investigating the electrical properties of dielectric liquid due to the difference of electron beam dose. To measure the physical properties of transformer oil, courier Transform-Infrared Spectroscopy is investigated. And the study far the electrical properties is made by measuring the volume resistivity of each specimen. By means of the result from this experiments, it is introduced that the movement of carrier to contribute to the volume resistivity on the electrical properties.

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A Study on the Method for Mitigation of Streaming Electrifiction by the Improvement of Flow Condition in the Oil Folw System of Transformer (변압기 절연유의 순환 계통에서의 흐름 조건의 개선에 의한 유동대전현사의 완화 방법에 관한 연구)

  • 권석두;남상천
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.43 no.4
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    • pp.594-600
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    • 1994
  • The maximum charge accumulation in transformers caused by streaming electrification is commonly observed on the bottom area of transformer winding(i.e.the oil inlet of transformer winding). It is because turbulent flows occur in this portion of transformers. Consequently, if we are to reduce the maximum charge accumulation of transformers, it is important that we should have a good understanding of the conditions of the occurence of partial turbulent flows in the oil inlet of transformer winding. With this point in mind, a simple flow model was designed in this study in order to simulate oil flow in the insulation ducts of power transformers. As a method for mitigating charge accummulation, attention was given to (a) a flow path design for the improvement of flow conditions, and (b) the charge tendency of the material used this design. The results of this study show that the above method is useful for mitigating charge accumulation.

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