• Title, Summary, Keyword: Transformer oils

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Research of Accelerated Aging According to Long-term Stability of Vegetable Oil (식물성절연유의 가속열화에 따른 장기적 안정성 분석)

  • Choi, Sun-Ho;Huh, Chang-Su
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.8
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    • pp.1148-1152
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    • 2012
  • The vegetable-based insulating oils are substitutes for mineral oils in oil-filled transformer. The important properties of vegetable insulating oil is their higher flash/fire point and biodegradability than conventional mineral oils. The large oil-filled transformer eliminate the risk of explosion and fire should the transformer fail and oil ignite owing to high flash/fire point of vegetable insulating oil. In addition, higher biodegradability of vegetable insulating oils can let the oil spill damage reduced. In this experiment, the real oil-filled transformers using mineral oil and vegetable oil have accelerated aging. After working on the 100% accelerated aging experiment were conducted comparing the transformer. The hottest-spot temperature using thermal coefficients were calculated to determin the degree of accelerated aging. As a result, apply mineral oil transformer in accordance with the accelerated aging life come to an end. In contrast, vegetable insulating oils showed the opposite characteristics. Vegetable insulating oil compared to the mineral oil are found to be an long life. As a result, the vegetable oil has a long-term stability.

Volume Resistivity Characteristics of Transformer Oils Contained BTA (BTA가 참가된 변압기유의 체적고유저항특성)

  • 이용우;송병기;김기택;김석환;김왕곤;홍진웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.257-260
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    • 1997
  • In order to investigate the volume resistivity on the electrical properties of transformer oils, the Transformer oils contained BTA is prepared, which was classified by the contents of BTA, such as 1[ppm], 10[ppm], 20[ppm], 30[ppm], 50[ppm], respectively. To measure the physical properties of transformer oils contained BTA, Fourier Transform Infrared Spectroscopy is investigated. And for the study of electrical properties is made by measuring the volume resistivity of each specimen. As result of this experiments, it is confirmed that the volume resistivity characteristics of specimen contained BTA 10[ppm] is superior.

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Dissolved Gas Analysis of Environment-Friendly Vegetable Insulating Oils (친환경 식물성 절연유의 유중가스 분석)

  • Choi, Sun-Ho;Kim, Kwan-Sik;Huh, Chang-Su
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.4
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    • pp.238-243
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    • 2015
  • The vegetable insulating oils are substitute for the mineral oil in power transformer. Vegetable insulating oils has higher flash/fire point and biodegradability than conventional mineral oils. In this paper, we investigated the dissolved gas analysis of vegetable oils. In the experiment, I had to accelerated aging under the same conditions mineral oil and vegetable oils. Accelerated aging proceeded to about 100% of the life of oil-filled transformer. In addition, we performed gas analysis of insulating oil of accelerated aging progress. The experiment results of the five gases was measured with the exception of Hydrogen and Acetylene. The mineral oil and vegetable oils gas is generated in a similar tendency depending on the accelerated aging. As a result, vegetable oils, can be dissolved gas analysis by method such as mineral oil.

Dielectric Breakdown Voltage According to Flow Velocity and Temperature of Vegetable Oils (식물성절연유의 유동속도와 온도에 따른 절연파괴전압)

  • Choi, Sun-Ho;Huh, Chang-Su
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.6
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    • pp.821-826
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    • 2012
  • The streaming electrification process of vegetable insulating oils occurring when the oils contacted with solid material in a high power transformer circulation system seems to cause electrical discharge incidents and may cause failures. We therefore measured the dielectric breakdown voltage tendency of vegetable insulating oils flowing on the surface of the charging device with various velocity and temperature. First, the relation between the velocity and breakdown voltage tendency of vegetable oils, can be explained by volume effect and v-t effect. Second, experimental results show that applied voltage have little effect on dielectric breakdown voltage, when vegetable insulating oils used for large power transformer.

Study on the synthesis and characterization of soybean based transformer oils (대두유 에스테르계 절연유의 합성과 분석)

  • Han, Dong-Hee;Cho, Han-Goo;Han, Se-Won;Ahn, Myeong-Sang;Oho, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.244-245
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    • 2005
  • Electrical insulation is one of the most important parts in a high voltage apparatus. Traditionally mineral oils and synthetic esters have been widely used as dielectric coolants for power transformers. Recently, researchers are interested in the environmental friendly vegetable oil from environmental viewpoint. This paper reports on the synthesis and characterization of soybean based ester oils. Two different types of soybean based transformer oils, named as methyl ester and isopropyl ester were synthesized. The synthesis of these esters was achieved by transesterification reactions of soybean oil and alcohol in the presence of catalyst. The GC and NMR spectroscopic analysis of the esters have been performed. The thermal stability of the esters was determined by thermal gravimetric analysis(TGA).

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Research of Flow Velocity and BTA According to the Streaming Electrification of Vegetable Insulating Oils (식물성 절연유의 유속과 BTA에 따른 유동대전 현상 연구)

  • Choi, Sun-Ho;Bang, Jeong-Ju;Huh, Chang-Su
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.10
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    • pp.791-797
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    • 2012
  • Mineral insulating oils are an important insulating materials in oil-filled transformer. However, the mineral oil is the cause of the environmental problem. The vegetable oils are substitutes for mineral oil because of its biodegradability characteristic. As large size and high rating of the transformer increases, the losses increase at a faster rate. So insulating oil is forced circulation in the oil-filled transformer by using oil pumps. The flow electrification occurs when insulating oil was forced to be circulated. To check the flow electrification, had conducted experiments varying factors. As a result, the streaming electrification could see the changes according to flow velocity, oil temperature and insulation materials.

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

  • 이인성;신현택;이종필;이수원;홍진웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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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∼100[$^{\circ}C$], we are made researches AC breakdown in the gap of 500∼2,500[$\mu\textrm{m}$]. The classification for the physical properties of oil for oil-immersed transformer by FTH and $^1$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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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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    • 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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Electrical Properties of Transformer Oils (III) (변압기유의 전기적인 특성 (III))

  • 이용우;조돈찬;신성권;이재호;김왕곤;홍진웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.293-297
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    • 1995
  • In order to investigate the electrical properties of Transformer Oils, Volume Resistivity for transformer oils was made researches. in this paper, the specimen was produced by irradiation of electron beam, which is divided by the dose, 12[Mrad], 24[Mrad], 36[Mrad]. By investigating the electrical properties of dielectric liquid due to the difference of electron beam irradiation the effect of electron beam irradiation was studied. To measure the physcial properties of transformer Oils, Fourier transfer infrared spectroscopy was investigated. And the study for the electrical properties of dielectric liquid was made by measuring volume resistivity of specimen. the Electrode for the measuring Volume resistivity is formed coaxial cylindrical shape, and its geometric capacitance is confirmed to 16[pF]. In this experiments, Highmegohm meter which is model VMG-1000, was used for the measuring volume resistivity. the applying voltages were DC 100, 250, 500, 1000[V] in the temperature range of 20∼120[$^{\circ}C$]. By means of the result from this experiment the movement of carrier and the physcial constants to contribute dielectric properties is introduced.

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