Other Articles by Authors

Aminudin S.

Authors and WSEAS

Aminudin S.

WSEAS Transactions on Environment and Development

Print ISSN: 1790-5079
E-ISSN: 2224-3496

Volume 13, 2017

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of WSEAS Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.

Volume 13, 2017

Investigation on Thermal Aging of Ester from Palm Oil and Kraft Paper Composite Insulation System for High Voltage Transformer

AUTHORS: Suwarno, Aminudin S.

Download as PDF

ABSTRACT: Mineral oil is widely being used as insulation for high voltage equipments such as transformer due to its excellent dielectric properties. Recently, due to environment consideration and the long term availability, organic liquid insulations from plantations are being introduced. However, the performance of such insulations in composite with paper should be investigated in order to maintain the performances of high voltage equipments in the electric power system. This paper reports the experimental results on the effects of thermal aging on the properties of natural ester from palm oil and Kraft paper composite insulation.The samples used in these experiments were natural ester from palm oil and kraft paper transformer insulation. The ester samples of 800 ml and 6 gram of kraft insulation paper were put together in heat-resistant hermetic bottles to simulate actual condition of transformator.All samples were subjected to thermal aging condition for duration of 336 hours to 672 hours at 120oC and 150oC in a controllable oven. The properties of new sample as well as thermally aged samples were investigated. Dielectric properties such as breakdown voltage, resistivity, water content were measured and dissolved gas analysis were conducted. The chemical element change was measured using JEOL 6510 EDS (energy dispersive X-ray spectroscopy) with accelerated voltage up to 30 kV. The experimental results showed that thermal aging process greatly affected the breakdown voltage and resistivity. At initial stage of thermal aging application the breakdown voltage increased significantly from 33.2 kV to 43.9 kV due to the reduction of water content. At the later time, however, the breakdown voltage reduced due to the drastic increase of oxidation by product which was indicated by the darker color. Resistivity reduced drastically from 8.5 TΩ.cm to 1.3 TΩ.cm after aging at 150oC for duration of 672 hour. Dissolved gas analysis indicated that thermal aging in ester-paper composite insulation released, CH4 (Methane), C2H6 (ethane), and CO (Carbon Monoxide). The EDS analysis showed that during aging the C element increased while O element decreased. Tensile strength of paper reduced significantly with thermal aging. EDS data of Kraft paper aged at 120oC for a duration of 4 weeks (672 hours) showed that the aged paper consists of 3 elements, C (75.23 %) , O (21.69 % ) and K (3.08%). C was observed at energy of 0.277 keV, O at energy of 0.525 keV while K was observed at energy of 3.312 keV. Experimental results revealed that C increased with aging while O decreased with aging. On the other hand oxygen reduced from 41.17 % to 21.69 % because the oxygen from the paper reacted with oil in an oxidation and release CO gas as confirmed by DGA (dissolved gas analysis). Similar behavior was observed for aging at 150oC.

KEYWORDS: Palm oil, ester, Kraft paper, dielectric properties, tensile strength, thermal aging, high voltage transformer, DGA, EDS


[1] McShane, C.P., Vegetable-Oil-Based Dielectric Coolant, IEEE Industry Applications Magazine,Vol. 3, Issue 3, 2002, pp.34-41.

[2] E. Gockenbach and H. Borsi, 'Performance and new application of ester liquids,' IEEEInternational Conference on Dielectric Liquids, 2002, pp. 203-206.

[3] Z.H. Shah, Q. A. Tahir, “Dielectric properties of Vegetable Oils”. Journal of Scientific Research, Vol. 3 , No. 3, 2011, pp. 481-492.

[4] H. Borsi, 'Dielectric behavior of silicone and ester fluids for use in distribution transformers,' IEEE Transactions on Electrical Insulation, vol. 26, no. 4, 1991, pp. 755-762. 0% 20% 40% 60% 80% 100% Percentage temperature (deg) and aging time (h) K O C

[5] Suwarno, I.S Dharma, “Dielectric Properties of Mixtures between Mineral Oil and Natural Esther from Palm Oil”, WSEAS Transaction on Power System, Vol 3, Issue 2, 20028, pp. 37- 46.

[6] L. Dix; C. P. McShane; H. R. Moore; S. Moore; J. Murphy; T. Prevost; S. D. Smith,“Progress report on natural esters for distribution and power transformers” IEEE/PES Conference and exhibition on Transmission and Distribution, Dallas, Texas, USA, 2006, pp. 15-17.

[7] Suwarno and F. Salim, 'Effects of Electric Arc on The Dielectric Properties of Liquid Dielectrics,' IEEE 8th International Conference on Properties & applications of Dielectric Materials, bali 2006, pp. 482-485.

[8] C. Perrier, A. Beroual, ”Experimental Investigations on Mineral and Ester Oils for Power Transformers” Conf. Rec. IEEE Int. Symp. Electr. Insul., 2008, pp. 178-181.

[9] J. Jung-Il, A. Jung-Sik, and H. Chan-Su, 'Accelerated aging effects of mineral and vegetable transformer oils on medium voltage power transformers,IEEE Transactions on Dielectrics and Electrical Insulation, vol. 19, 2012, pp. 156-161.

[10] Christoph Krause; Uldis Kaminskis; Andreas Wild; Kevin Rapp; Alan Sbravati, Dielectric prototype test of a full-scale 420 kV power transformer HV lead exit insulated with natural ester liquid, IEEE Electrical Insulation Conference (EIC), 2016, pp. 129-133

[11] Norazhar Abu Bakar; A. Abu-Siada; S. Islam, A review of dissolved gas analysis measurement and interpretation techniques, IEEE Electrical Insulation Magazine, Vol. 30, Issue 3, 2014, pp. 39-40

[12] M. Arshad and S. M. Islam, 'Significance of cellulose power transformer condition assessment, IEEE Transactions on Dielectrics and Electrical Insulation, vol. 18, Issue 5,2011, pp. 1591-1598.

[13] Abu-Siada and S. Islam, 'A new approach to identifY power transformer criticality and asset management decision based on dissolved gasin-oil analysis,IEEE Transactions on Dielectrics and Electrical insulation, vol. 19, Isue 3, 2012, pp. 1007-1012.

[14] R. Tamura, H. Anetai, T. Ishii, and T. Kawamura, 'Diagnostic of ageing deterioration of insulating paper,' JIEE Proc Pub A, vol. 101, p. 30, 1981.

[15] G. Zadora, Z. Brozek-Mucha, SEM-EDX, A useful tool for Forensic examinations, Material, chemistry and Physics, Vol. 81, issue 2-3, 2003, pp. 345-348

[16] M. Nusp, W. Wegscheider, J. Angeli, W. Posch, M. Mayr, Qualitative and quantitative determination of micro-inclusions by automated SEM/EDX analys, Analytical and Bioanalytical Chemistry, Vol. 379, Issue 4, 2004, pp 640–645

[17] F. Fay, I. Linossier, V. Langlois, D. Haras SEM and EDX analysis: Two powerful techniques for the study of antifouling paints, Progress in Organic Coatings, Vol. 54, Issue 3, 2005, Pages 216–223

[18] C. P. McShane, K. J. Rapp, J. L. Corkran, G. A. Gauger and J. Luksich, Aging of Kraft paper in natural ester dielectric fluid, IEEE 14th Int'l. Conf on Dielectr. Liquids,Graz 2002, pp. 173- 177.

[19] IEEE 1538-2000, IEEE Guide for Determination of maximum Winding Temperature Rise in Liquid-Filled Transformers

[20] Insulating Liquids-Determination Of The Breakdown Voltage At Power Frequency-Test Method , IEC Standard , No. 60156, 1995,

[21] Insulating liquids - Measurement of relative permittivity, dielectric dissipation factor (tan d) and d.c. resistivity, IEC Standard, No IEC 60247:2004

[22] ASTM-D1533-12 Standard Test Method for Water in Insulating Liquids by Coulometric Karl Fischer Titration

[23] IEEE Guide for the Interpretation of Gases Generated in Oil-Immersed Transformers, IEEE Standard No. C57.104-2008, 2009

[24] Standard Test Method for Analysis of Gases Dissolved in Electrical Insulating Oil by Gas Chromatography, ASTM Standard, No D3612 - 02(2009)

WSEAS Transactions on Environment and Development, ISSN / E-ISSN: 1790-5079 / 2224-3496, Volume 13, 2017, Art. #10, pp. 75-84

Copyright © 2017 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.0

Bulletin Board


The editorial board is accepting papers.

WSEAS Main Site