Nguyen Van Dung, Nguyen Thi Xuan Thi, Le Vinh Truong

Main Article Content

Abstract

This study evaluated the feasibility of using methyl ester prepared from waste cooking oil for electrical insulation in distribution transformers. Methyl ester is produced by a transesterification reaction between waste cooking oil and methanol using sodium hydroxide as a catalyst. The physicochemical parameters and breakdown voltage of the methyl ester were determined. The effects of ageing on breakdown voltage, viscosity and acid value of methyl ester were also investigated. In addition, the breakdown voltage of Kraft paper impregnated with methyl ester was determined. Experimental results showed that methyl ester from waste cooking oil had low viscosity (5.17 cSt) and high breakdown voltage (40.3 kV). Other parameters also meet ASTM D6871 except for the pour and flash points. Ageing insignificantly affected the breakdown voltage of the methyl ester. After ageing, the breakdown voltage of the methyl ester increased to 42.1 kV. However, the viscosity of the methyl ester also increased by 23.5% and the acid value increased by 79.2 times. Finally, the breakdown voltage of Kraft paper impregnated with the methyl ester was about 5-10% lower than that of paper impregnated with the mineral oil. 

Keywords: Methyl ester, waste cooking oil, insulating liquid, transformers.

References

[1] Working Group A2.35, Technical Brochure 436-Experiences in Service with New Insulating Liquids, Cigre, 2010.
[2] M. N. Deraman, N. A. Bakar, N. H. A. Aziz, I. S. Chairul, S. A. Ghani, The Experimental Study on the Potential of Waste Cooking Oil as a New Transformer Insulating Oil, Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, Vol. 69, No. 1, 2020, pp. 74-84, https://doi.org/10.37934/arfmts.69.1.7484.
[3] I. S. Chairul, N. A. Bakar, M. N. Othman, S. A. Ghani, M. N. Deraman, Development of Waste Cooking Oil Methyl Ester as Potential Electrical Insulating Fluid for Power Transformer, ARPN Journal of Engineering and Applied Sciences, Vol. 13, No. 20, 2018, pp. 8154-8162.
[4] M. M. Ghislain, O. B. Gerard, T. N. Emeric, M. I. Adolphe, Improvement of Environmental Characteristics of Natural Monoesters for Use as Insulating Liquid in Power Transformers, Environmental Technology and Innovation, Vol. 27, 2022, pp. 102784, https://doi.org/10.1016/j.eti.2022.102784.
[5] N. V. Dung, H. L. Huong, The Effect of Antioxidants on the Physical and Chemical Properties of Rice Oil, Corn Oil, Peanut Oil and Kraft Paper, IEEE Trans, Dielectr, Electr, Insul, Vol. 27, No. 5, 2020, pp. 1698-1706,
https://doi.org/10.1109/TDEI.2020.008422.
[6] S. Tenbohlen, M. Koch, Ageing Performance and Moisture Solubility of Vegetable Oils for Power Transformers, IEEE Trans, Power, Del, Vol. 25, No. 2, 2010, pp. 825-830, https://doi.org/10.1109/TPWRD.2009.2034747.
[7] H. M. Wilhelm, M. B. C Stocco, L. Tulio, W. Uhren, S. G. Batista, Edible Natural Ester Oils as Potential Insulating Fluids, IEEE Trans. Dielectr, Electr, Insul, Vol. 20, No. 4, 2013, pp. 1395-1401, https://doi.org/10.1109/TDEI.2013.6571461.
[8] L. E. Lundgaard, W. Hansen, S. Ingebrigtsen, Ageing of Mineral Oil Impregnated Cellulose by Acid Catalysis, IEEE Trans, Dielectr, Electr, Insul, Vol. 15, No. 2, 2008, pp. 540-546, https://doi.org/10.1109/TDEI.2008.4483475.
[9] M. Unge, S. Singha, N. V. Dung, D. Linhjell, S. Ingebrigtsen, L. E. Lundgaard, Enhancements in the Lightning Impulse Breakdown Characteristics of Natural Ester Dielectric Liquids, Applied Physics Letters, Vol. 102, No. 17, 2013, pp. 172905, https://doi.org/10.1063/1.4803710.
[10] M. K. Lam, K. T. Lee, Production of Biodiesel Using Palm Oil, Biofuels, 2011, pp. 353-374, https://doi.org/10.1016/B978-0-12-385099-7.00016-4.