Your browser does not support JavaScript!
http://iet.metastore.ingenta.com
1887

access icon free Understanding the ageing behaviour of transformer oil–paper insulation with ester and mixed dielectric fluids

© The Institution of Engineering and Technology
Received 02/04/2018, Accepted 06/05/2018, Published 16/05/2018

Study of alternate fluids for transformer and their combination with traditional ones is an interesting area of research. The intent of this work is to investigate the thermal ageing performance of ester oils (synthetic and natural), and mixed oil vis-à-vis mineral oil. All the samples were thermally stressed at 110, 140, 160, and 185°C for 2 weeks each. Dissolved decay contents in oil and linear thermal expansion coefficients of solid insulation have been studied using ultraviolet visible infrared spectroscopy and dilatometry analysis, respectively, as per ASTM standards. Change in functional groups of the insulation oils with ageing have been understood by Fourier transform infrared spectroscopy analysis. Additionally, diffusion of oil–moisture mixture into paper with ageing and the corresponding effect on dielectric strength of paper has been also examined using ASTM standards. It is observed that the use of synthetic ester (SE) and addition of SE to mineral insulating oil lead to improved performance of oil–paper insulation system with retarding the rate of degradation of the insulation system.

Inspec keywords: paper; ageing; electric strength; thermal expansion; moisture; infrared spectra; power transformer insulation; insulating oils; thermal stresses; Fourier transform spectra; transformer oil

Other keywords: mixed dielectric fluids; dilatometry analysis; dielectric strength; temperature 185.0 degC; temperature 160.0 degC; alternative fluids; temperature 110.0 degC; time 2.0 week; ultraviolet visible infrared spectroscopy; synthetic oil; ageing behaviour; solid insulation; transformer oil-paper insulation; dissolved decay contents; thermal stress; linear thermal expansion coefficients; ASTM standards; ester oils; oil-moisture mixture; temperature 140.0 degC; mineral insulating oil; natural oil

Subjects: Transformers and reactors; Dielectric materials and properties; Organic insulation

References

    1. 1)
      • 2. Xiao, Y., Wang, Z.D.: ‘Creepage discharge on pressboards in synthetic and natural ester transformer liquids under ac stress’, IET Electr. Power Appl., 2013, 7, (3), pp. 191–198.
    2. 2)
      • 14. Liao, R., Hao, J., Chen, G., et al: Quantitative analysis of aging condition of oil–paper insulation by frequency domain spectroscopy. IEEE Trans. Dielectr. Electr. Insul., 2012, 19, pp. 821–830.
    3. 3)
      • 11. Hamdi, A., Fofana, I., Djillali, M.: ‘Stability of mineral oil and oil–ester mixtures under thermal aging and electrical discharges’, IET Gener. Transm. Distrib., 2017, 11, (9), pp. 2384–2392.
    4. 4)
      • 12. Liao, R., Liu, J., Yang, L., et al: ‘Quantitative analysis of insulation condition of oil–paper insulation based on frequency domain spectroscopy’, IEEE Trans. Dielectr. Electr. Insul., 2015, 22, pp. 322–334.
    5. 5)
      • 22. Fofana, I., Bouaicha, A., Farzaneh, M.: ‘Characterization of aging transformer oil–pressboard insulation using some modern diagnostic techniques’, Euro. Trans. Electr. Power, 2011, 21, (1), pp. 1110–1127.
    6. 6)
      • 17. Ekanayake, C., Gubanski, S.M., Graczkowski, A., et al: ‘Frequency response of oil impregnated pressboard and paper samples for estimating moisture in transformer insulation’, IEEE Trans. Power Deliv., 2006, 21, pp. 1309–1317.
    7. 7)
      • 8. Mohan Rao, U., Sood, Y.R., Jarial, R.K.: ‘Performance analysis of alternate liquid dielectrics for power transformers’, IEEE Trans. Dielectr. Electr. Insul., 2016, 23, (4), pp. 2475–2484.
    8. 8)
      • 18. Saha, T.K., Purkait, P.: ‘Investigation of polarization and depolarization current measurements for the assessment of oil–paper insulation of aged transformers’, IEEE Trans. Dielectr. Electr. Insul., 2004, 11, pp. 144–154.
    9. 9)
      • 26. ‘Standard test method for linear thermal expansion of solid materials with a push-rod dilatometer’, ASTM Standard, ASTM E228-11, 1 April2011.
    10. 10)
      • 19. Linhjell, D., Lundgaard, L.E., Gafvert, U.: ‘Dielectric response of mineral oil impregnated cellulose and the impact of aging’, IEEE Trans. Dielectr. Electr. Insul., 2007, 14, pp. 156–169.
    11. 11)
      • 5. Fofana, I., Wasserberg, V., Borsi, H., et al: ‘Challenge of mixed insulating liquids for use in high-voltage transformers, Part 1: investigation of mixed liquids’, IEEE Electr. Insul. Mag., 2002, 18, (3), pp. 18–31.
    12. 12)
      • 6. Fofana, I., Wasserberg, V., Borsi, H., et al: ‘Challenge of mixed insulating liquids for use in high-voltage transformers, part 2: investigations of mixed liquid impregnated paper insulation’, IEEE Electr. Insul. Mag., 2002, 18, (4), pp. 5–16.
    13. 13)
      • 13. Hadjadj, Y., Meghnefi, F., Fofana, I., et al: On the feasibility of using poles computed from frequency domain spectroscopy to assess oil impregnated paper insulation conditions. Energies, 2013, 6, pp. 2204–2220.
    14. 14)
      • 9. Loiselle, L., Fofana, I., Sabau, J., et al: ‘Comparative studies of the stability of various fluids under electrical discharge and thermal stresses’, IEEE Trans. Dielectr. Electr. Insul., 2015, 22, (5), pp. 2491–2499.
    15. 15)
      • 20. Martin, D., Saha, T.K., Gray, T., et al: ‘Determining water in transformer paper insulation: effect of measuring oil water activity at two different locations’, IEEE Electr. Insul. Mag., 2015, 31, (3), pp. 18–25.
    16. 16)
      • 23. Bandara, K., Ekanayake, C., Saha, T.K.: ‘Understanding the aging aspects of natural ester based insulation liquid in power transformer’, IEEE Trans. Dielectr. Electr. Insul, 2016, 23, (1), pp. 246–257.
    17. 17)
      • 24. ‘Test method for determination of the relative content of dissolved decay products in mineral insulating oils by spectrophotometry’, ASTM Standard, ASTM D6802-02, 10 June2002.
    18. 18)
      • 29. Martin, D., Wang, Z.D.: ‘Statistical analysis of the AC breakdown voltages of ester based transformer oils’, IEEE Trans. Dielectr. Electr. Insul., 2008, 15, (4), pp. 1044–1050.
    19. 19)
      • 16. Zhang, Y., Liu, J., Zheng, H., et al: ‘Study on quantitative correlations between the aging condition of transformer cellulose insulation and the large time constant obtained from the extended Debye model’, Energies, 2017, 10, p. 1842.
    20. 20)
      • 7. Perrier, C., Beroual, A., Bessede, J.L.: ‘Improvement of power transformers by using mixtures of mineral oil with synthetic esters’, IEEE Trans. Dielectr. Electr. Insul., 2006, 13, (3), pp. 556–564.
    21. 21)
      • 28. Abubakar, A.S., Nazri, F., Muhamad, N.A.: ‘Wetting characteristics for kraft paper immersed in mineral and biodegradable insulation oils’. IEEE Int. Power Engineering and Optimization Conf., Langkawi, Malaysia, 2014, pp. 194–198.
    22. 22)
      • 4. Liao, R-.j., Tang, C., Yang, L-.j.: ‘Thermal aging micro-scale analysis of power transformer pressboard’, IEEE Trans. Dielectr. Electr. Insul., 2008, 15, (5), pp. 1281–1287.
    23. 23)
      • 25. Fernández, O.H., Fofana, I., Jalbert, J., et al: ‘Aging characterization of electrical insulation papers impregnated with synthetic ester and mineral oil: correlations between mechanical properties, depolymerization and some chemical markers’, IEEE Trans. Dielectr. Electr. Insul., 2018, 25, (1), pp. 217–227.
    24. 24)
      • 15. Liu, J., Zheng, H., Zhang, Y., et al: ‘Grey relational analysis for insulation condition assessment of power transformers based upon conventional dielectric response measurement’, Energies, 2017, 10, p. 1526.
    25. 25)
      • 21. Martin, D., Saha, T.K., Dee, R., et al: ‘Determining water in transformer paper insulation: analyzing aging transformers’, IEEE Electr. Insul. Mag., 2015, 31, (5), pp. 23–32.
    26. 26)
      • 27. ‘Standard test method for dielectric breakdown voltage and dielectric strength of solid electrical insulating materials at commercial power frequencies’, ASTM Standard, ASTM D149-09, 1 April2013.
    27. 27)
      • 1. Fernandez, I., Ortiz, A., Delgado, F., et al: ‘Comparative evaluation of alternative fluids for power transformers’, Electr. Power Syst. Res., 2013, 98, pp. 58–69.
    28. 28)
      • 3. Abdelmalik, A.A.: ‘Analysis of thermally aged insulation paper in a natural ester-based dielectric fluid’, IEEE Trans. Dielectr. Electr. Insul., 2015, 22, (5), pp. 2408–2414.
    29. 29)
      • 10. Mohan Rao, U., Sood, Y.R., Jarial, R.K.: ‘Oxidation stability enhancement of a blend of mineral and synthetic ester oils’, IEEE Electr. Insul. Mag., 2016, 32, (2), pp. 43–47.
http://iet.metastore.ingenta.com/content/journals/10.1049/iet-smt.2018.0110
Loading

Related content

content/journals/10.1049/iet-smt.2018.0110
pub_keyword,iet_inspecKeyword,pub_concept
6
6
Loading
Print this page
This is a required field
Please enter a valid email address