• Title, Summary, Keyword: Vegetable insulating oils

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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.

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.

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.

Research of Flow Electrification Phenomena of the used Environment-Friendly Vegetable Insulating Oils (친환경 식물성절연유의 유동대전현상 연구)

  • Choi, Sun-Ho;Huh, Chang-Su
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.4
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    • pp.580-584
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    • 2012
  • The insulating oils perform a cooling and insulation action in electric power transformer. The mineral oil has immanent fire dangerousness and environmental contamination problem. Vegetable insulating oil has higher ignition point, flash point and more excellent biodegradability than conventional mineral oil. In a real oil-filled transformers, some of the power is dissipated in the form of heat. And transformer require the heat to be removed from the winding and insulator by forced convection of the insulating oil. The flow electrification occurs when insulating oil was forced to be circulated. In this paper, influence of temperature, velocity of flow, and insulating pipe and diameter on streaming electrification of vegetable insulating oil was investigated using forced circulation apparatus. Temperature effects were most significant, and it showed a peak in the temperature $30^{\circ}C$ to $35^{\circ}C$ at insulating and copper pipe. The change of flow electrification according to area variety could be checked by change of diameter.

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.

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.

A Study on Corona Inception Voltage and Dielectric Characteristics of Thermally Aged Mineral and Vegetable Insulation Oil in Medium Voltage Power Transformer (식물유 및 광유를 사용한 배전변압기의 열열화에 따른 절연유의 코로나 개시전압 및 전기적 특성에 대한 연구)

  • Jeong, Jung-Il;Huh, Chang-Su
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.12
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    • pp.1745-1750
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    • 2017
  • Starting from the distribution transformer, the insulation oil for the oil immersed power transformer is being used to convert the vegetable oil from the existing mineral oil. Vegetable oil is better in temperature characteristics and insulation performance, is not toxic, and has better biodegradable characteristic than that of mineral oil. In order to investigate the corona inception voltage and dieclectic charateristics of the two insulating oils, three oil immersed transformers using mineral oil and vegetable oil were made and thermal cyclic aged. In this paper, the changes in the corona discharge inception voltage, chemical and electrical properties of the two sampled insulating oils from the transformers had been studied.

Renewable Low-viscosity Dielectrics Based on Vegetable Oil Methyl Esters

  • Yu, Hui;Yu, Ping;Luo, Yunbai
    • Journal of Electrical Engineering and Technology
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    • v.12 no.2
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    • pp.820-829
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    • 2017
  • Vegetable oil dielectrics have been used in transformers as green alternatives to mineral insulating oils for about twenty years, because of their advantages of non-toxic, biodegradability, and renewability. However, the viscosity of vegetable oils is more than 3 times of mineral oils, which means a poor heat dissipation capacity. To get low-viscosity dielectrics, transesterification and purification were performed to prepare vegetable oil methyl esters in this study. Electrical and physical properties were determined to investigate their potential as dielectrics. The results showed that the methyl ester products had good dielectric strengths, high water saturation and enough fire resistance. The viscosities (at $40^{\circ}C$) were 0.2 times less than FR3 fluid, and 0.7 times less than mineral oil, which indicated superior cooling capacity as we expected. With the assistance of 0.5 wt% pour point depressants, canola oil methyl ester exhibited the lowest pour point ($-26^{\circ}C$) among the products which was lower than FR3 fluid ($-21^{\circ}C$) and 25# mineral oil ($-23^{\circ}C$). Thus, canola oil methyl ester was the best candidate as a low-viscosity vegetable oil-based dielectric. The low-viscosity fluid could extend the service life of transformers by its better cooling capacity compared with nature ester dielectrics.

Synthesis of POSS Derived Organic-Inorganic Hybrid Esters for Insulating Oil Applications

  • Choi, Kyeong-Min;Harshavardhan, S.J.;Sridhar, Ch.;Vijaykumar, B.V.D.;Kumar, Deepak;Jang, Kiwan;Lee, Man-Sig;Shin, Dong-Soo
    • Bulletin of the Korean Chemical Society
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    • v.35 no.9
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    • pp.2769-2773
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    • 2014
  • In this work, a new family of polyhedral oligomeric silsesquioxanes (POSS) based esters have been synthesized that consists eight ester functional groups. These are classified into Type-I and Type-II esters based on the starting materials, octakis(3-chloropropyl)silsesquioxane (Cl-POSS) and octakis(3-hydroxypropyldimethylsiloxy) octasilsesquioxane (OHPS) respectively. These new POSS type ester moieties can be used as insulating oils and oil additives in the transformers and also considered to be alternatives to mineral and vegetable oils that are presently used in the insulation system.

Suitability of Palm Based Oil as Dielectric Insulating Fluid in Transformers

  • Azis, Norhafiz;Jasni, Jasronita;Kadir, Mohd Zainal Abidin Ab;Mohtar, Mohd Nazim
    • Journal of Electrical Engineering and Technology
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    • v.9 no.2
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    • pp.662-669
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    • 2014
  • Mineral oil has been widely used as dielectric insulating fluid in transformers due to its excellent performance in-service. However, there are few issues with mineral oil such as it has poor biodegradability and could contaminate the environment if a spillage occurs. With the increasing tight regulation on safety and environment, alternative fluids for mineral oil are currently being investigated and among the suitable candidate is the vegetable oil. There are different types of vegetable oils and one of them is the palm based oil. At the moment, extensive research works are carried out to examine its feasibility to be applied in transformers. This paper will review the previous research works that were carried out to examine the suitability of palm based oil as dielectric insulating fluid in transformers. The physical and chemical properties of palm based oil are studied based on viscosity, acidity, oxidation stability and flash point. Next, the electrical characteristics of palm based oil are examined based on AC breakdown voltage, relative permittivity, dissipation factor and partial discharge.