Renewable Low-viscosity Dielectrics Based on Vegetable Oil Methyl Esters

다국어 초록 (Multilingual Abstract)

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℃) 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℃) among the products which was lower than FR3 fluid (-21℃) and 25# mineral oil (-23℃). 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.

목차 (Table of Contents)

• Abstract
• 1. Introduction
• 2. Materials and Methods
• 3. Results and Discussion
• 4. Conclusion
• References

참고문헌 (Reference)

1 C. P. McShane, "Vegetable-oil-based dielectric coolants" 8 (8): 34-41, 2002

2 M. A. G. Martins, "Vegetable oils, an alternative to mineral oil for power transformers-experimental study of paper aging in vegetable oil versus mineral oil" 6 (6): 7-13, 2010

3 T. Oommen, "Vegetable oils for liquid-filled transformers" 18 (18): 6-11, 2002

4 Y. Bertrand, "Vegetable oils as substitute for mineral insulating oils in medium-voltage equipments" CIGRE 2004

5 M. Rafiq, "Use of vegetable oils as transformer oils–a review" 52 : 308-324, 2015

6 A. Srivastava, "Triglycerides-based diesel fuels" 4 (4): 111-133, 2000

7 C. Watkins, "Transforming the transformer industry" 19 (19): 524-526, 2008

8 U. Schuchardt, "Transesterification of vegetable oils : a review" 9 (9): 199-210, 1998

9 D. Martin, "Thermal analysis of two transformers filled with different oils" 1 (1): 39-45, 2014

10 S. Liang, "Thermal aging characteristics of natural ester impregnated Kraft paper and thermally upgraded paper insulation" 2008

11 L. Meher, "Technical aspects of biodiesel production by transesterification — a review" 10 (10): 248-268, 2006

12 Norhafiz Azis, "Suitability of Palm Based Oil as Dielectric Insulating Fluid in Transformers" 대한전기학회 9 (9): 662-669, 2014

13 D. Martin, "Statistical analysis of the AC breakdown voltages of ester based transformer oils" 15 (15): 1044-1050, 2008

14 C. P. McShane, "Relative properties of the new combustion-resist vegetable-oil-based dielectric coolants for distribution and power transformers" 37 (37): 1132-1139, 2001

15 H. Borsi, "Properties of ester liquid Midel 7131 as an alternative liquid to mineral oil for transformers" ICDL 2005

16 X. Wang, "Particle effect on breakdown voltage of mineral and ester based transformer oils" 2008

17 W. Neff, "Oxidative stability of purified canola oil triacylglycerols with altered fatty acid compositions as affected by triacylglycerol composition and structure" 71 (71): 1101-1109, 1994

18 S. Z. Erhan, "Oxidation and low temperature stability of vegetable oil-based lubricants" 24 (24): 292-299, 2006

19 S. C. Cermak, "New crop oils — Properties as potential lubricants" 44 : 232-239, 2013

20 Y. Du, "Moisture solubility for differently conditioned transformer oils" 8 (8): 805-811, 2001

21 T. O. Rouse, "Mineral insulating oil in transformers" 14 (14): 6-16, 1998

22 S. Z. Erhan, "Lubricant basestocks from vegetable oils" 11 (11): 277-282, 2000

23 R. Dunn, "Low-temperature properties of triglyceride-based diesel fuels : transesterified methyl esters and petroleum middle distillate/ester blends" 72 (72): 895-904, 1995

24 M. Amanullah, "Low viscosity vegetable oil-based dielectric fluids"

25 M. Heathcote, "J & P transformer book" Newnes 2011

26 M. J. Ramos, "Influence of fatty acid composition of raw materials on biodiesel properties" 100 (100): 261-268, 2009

27 S. Boyde, "Green lubricants. Environmental benefits and impacts of lubrication" 4 (4): 293-307, 2002

28 D. Martin, "Further studies of a vegetable-oil-filled power transformer" 27 (27): 6-13, 2011

29 M. Shinke, "Fundamental studies on development of environment friendly vegetable oil filled transformer" 123 : 187-193, 2003

30 A. Röttig, "Fatty acid alkyl esters : perspectives for production of alternative biofuels" 85 (85): 1713-1733, 2010

31 A. Tekin, "Factors affecting the electrical resistivity of soybean oil methyl ester" 77 (77): 281-283, 2000

32 Y. Kasahara, "Consideration on the relationship between dielectric breakdown voltage and water content in fatty acid esters" 89 (89): 1223-1229, 2012

33 D. Cao, "Chromatographic analysis and fault diagnosis for transformer oil" China Electric Power Press 2010

34 A. S. Ramadhas, "Biodiesel production from high FFA rubber seed oil" 84 (84): 335-340, 2005

35 F. M. T. Luna, "Assessment of biodegradability and oxidation stability of mineral, vegetable and synthetic oil samples" 33 (33): 579-583, 2011

36 M. Amanullah, "Analyses of physical characteristics of vegetable oils as an alternative source to mineral oil-based dielectric fluid" 2005

37 T. Kanoh, "Analyses of electro-chemical characteristics of palm fatty acid esters as insulating oil" 2008

38 D. Martin, "An overview of the suitability of vegetable oil dielectrics for use in large power transformers" 2006

39 S. Tenbohlen, "Aging performance and moisture solubility of vegetable oils for power transformers" 25 (25): 825-830, 2010

40 C. P. McShane, "Aging of paper insulation in natural ester dielectric fluid" 2001

41 D. Y. Leung, "A review on biodiesel production using catalyzed transesterification" 87 (87): 1083-1095, 2010

42 T. Oommen, "A new vegetable oil based transformer fluid : development and verification" 2000

43 A. Kamal-Eldin, "A multivariate study of the correlation between tocopherol content and fatty acid composition in vegetable oils" 74 (74): 375-380, 1997

44 D. Martin, "A comparative study of the impact of moisture on the dielectric capability of esters for large power transformers" 2006

45 R. Liao, "A comparative study of physicochemical, dielectric and thermal properties of pressboard insulation impregnated with natural ester and mineral oil" 18 (18): 1626-1637, 2011