Lifetime estimation of cellulosic insulation material in palm fatty acid ester for power transformers

Tokunaga, Junko; Koide, Hidenobu; Mogami, Kenji; Kawanishi, Keizo; Hikosaka, Tomoyuki

doi:10.1109/tdei.2017.005693

Cited by 31 publications

(10 citation statements)

References 13 publications

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“…Therefore, in the process of pyrolysis, the natural ester insulating liquid will strengthen the hydrogen bond network with cellulose and prolong the life of the insulating paper. The results also confirm the experimental results that the dielectric properties and tensile strength of the insulating paper impregnated with natural ester will be relatively improved, and the insulating life will be significantly longer than that of the insulating paper impregnated with mineral oil [7,8,57]. The results also confirm that with ageing, natural ester and other esters insulating dielectric have a better effect on reducing breakdown voltage than mineral insulating oil [58].…”

Section: Hydrogen Bonds Analysis In the Pyrolysis Process Of Rbdposupporting

confidence: 83%

Investigation on micro‐mechanism of palm oil as natural ester insulating oil for overheating thermal fault analysis of transformers

Zheng

Li²,

Feng³

et al. 2021

High Voltage

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In order to explore the pyrolysis mechanism of palm oil as the natural ester insulating liquid from the molecular aspect, the ReaxFF reactive force field was used to simulate the pyrolysis process of palm oil. Firstly, the molecular models of the four main molecules of palm oil—tripalmitin, trilinolein, triolein, and tristearin—are constructed via density functional theory (DFT). Secondly, the vibrational frequencies of the four molecules are calculated, so as to calculate the infrared (IR) spectra. Thirdly, molecular dynamics (MD) simulations employing the ReaxFF method are performed to simulate the pyrolysis reaction of the palm oil system under different temperatures, so as to observe the generation pathways of major products used in the dissolved gas analysis (DGA) in the transformer thermal fault analysis. Finally, hydrogen bonds in the pyrolysis process are counted. It is found that the number of hydrogen bonds gradually increased with the increase of pyrolysis time and pyrolysis temperature. It reveals why the life of the insulating paper immersed with natural esters is prolonged, and why the breakdown voltage is reduced slowly in the actual experiment from another perspective. This study can provide theoretical guidance and effective reference for the thermal fault analysis of an insulating liquid using palm oil as raw material.

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Section: Hydrogen Bonds Analysis In the Pyrolysis Process Of Rbdposupporting

confidence: 83%

Investigation on micro‐mechanism of palm oil as natural ester insulating oil for overheating thermal fault analysis of transformers

Zheng

Li²,

Feng³

et al. 2021

High Voltage

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“…Tokunaga et al investigated the performance and estimated service life of solid insulation in PFAE-filled transformers [30]- [32]. They claimed that the lifetime of solid insulation in PFAE is 7.3 times higher than in mineral oil.…”

Section: A Performance Of Ester Fluids: Recent Progressmentioning

confidence: 99%

Alternative Dielectric Fluids for Transformer Insulation System: Progress, Challenges, and Future Prospects

et al. 2019

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Ester-based dielectric fluids have gained widespread popularity for applications in high voltage apparatus. Synthetic and natural esters have been subjected to research for decades vis-à-vis mineral insulating oils around the world. Although many researchers favor the application of ester fluids, utilities are still uncertain and application of these alternatives remains a challenge. The intent of this survey is to present recent research progress and highlight the state of the art of key aspects that should be emphasized in future research. The contemporary research scenarios pertaining to the performance of ester fluids versus mineral oils, miscibility, and retrofilling of insulating fluids are discussed. In addition, pre-breakdown phenomena, usage of esters in on-load tap changers, environmental and fire resistance properties, and use of esters in cold climates are also discussed. Importantly, challenges and future aspects that should be investigated to improve the existing knowledge of ester dielectric fluids for applications in transformer technology are highlighted.

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“…insulation papers with different kind of dielectric oils. The insulation solids that have been studied up till recently include: Kraft paper [6], aramid paper insulation [7], pressboard materials or even pre-thermally upgraded papers [8]. Paper degradation in all investigations has been analysed through different methods such as: degree of polymerization (DP) [9], mechanical tensile strength [10], infrared spectroscopy (FTIR) or even by differential scanning calorimetry [11], energy dispersive X-ray [12] or breakdown voltage [13], DP and tensile strength being the most common used techniques to evaluate the insulating paper condition.…”

Section: Introductionmentioning

confidence: 99%

Dielectric and Mechanical Assessment of Kraft and Diamond Dotted Paper Aged with Commercial Vegetable Oil

Franquet

Fernández

Ortiz

2020

2020 IEEE 3rd International Conference on Dielectrics (ICD)

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The use of vegetable oil (natural ester) in electrical devices like power transformers is increasing due to their high biodegradability and better safety. The lifespan of power trans-formers is mainly defined by cellulose insulation condition, which usually works together with dielectric oil as electrical insulation and also as mechanical winding protector and compactor. That is why the aim and results of this research shows us not only the dielectric parameters evolution, but also the relationship between the mechanical factors and the moisture content of thermal accelerated ageing processes, with commercial vegetable oil, of Kraft paper and Diamond Dotted Paper (DDP). These are two of the most common insulating materials in electric power transformers. In addition, the new tests have been done by a different method of paper ageing analysis.

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Lifetime estimation of cellulosic insulation material in palm fatty acid ester for power transformers

Cited by 31 publications

References 13 publications

Investigation on micro‐mechanism of palm oil as natural ester insulating oil for overheating thermal fault analysis of transformers

Investigation on micro‐mechanism of palm oil as natural ester insulating oil for overheating thermal fault analysis of transformers

Alternative Dielectric Fluids for Transformer Insulation System: Progress, Challenges, and Future Prospects

Dielectric and Mechanical Assessment of Kraft and Diamond Dotted Paper Aged with Commercial Vegetable Oil

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