Thermal aging test for transformer oil–paper insulation under over-load condition temperature

Thermal aging test for transformer oil–paper insulation under over-load condition temperature

For access to this article, please select a purchase option:

Buy article PDF
(plus tax if applicable)
Buy Knowledge Pack
10 articles for £75.00
(plus taxes if applicable)

IET members benefit from discounts to all IET publications and free access to E&T Magazine. If you are an IET member, log in to your account and the discounts will automatically be applied.

Learn more about IET membership 

Recommend to library

You must fill out fields marked with: *

Librarian details
Your details
Why are you recommending this title?
Select reason:
IET Generation, Transmission & Distribution — Recommend this title to your library

Thank you

Your recommendation has been sent to your librarian.

The accelerated thermal aging test is an effective method to simulate insulation material degradation in oil-immersed transformers. Traditionally, cellulose paper and mineral oil are heated up together at the same temperature when a thermal aging test is conducted. However, variation occurs between laboratory results and field conditions. Temperature gradients exist in real transformers, and each part of the winding is aged under various conditions. In order to rebuild temperature gradients and conduct a thermal aging test under this condition. First, 3D models with designed U-shape wingding which can guarantee different parts aged simultaneously under different temperatures are calculated for temperature field analysis. Then a thermal aging platform with a large current generator is proposed to construct temperature gradients in a thermal aging test. The large current generator helps to heat up the copper winding. Temperature sensors are installed in the aging tank to monitoring winding and oil temperature and control temperature. The aging temperature is selected according to the standard IEC 60076-7 for the over-load condition. The degree of polymerisation of the insulation paper is measured and properties of each layer of the insulation paper are analysed. Other aging products under both traditional test and method in this study are compared.


    1. 1)
      • 1. IEC 60076-7, Loading guide for oil-immersed power transformers, 2005–12.
    2. 2)
      • 2. IEEE Guide for loading mineral-oil-immersed transformers, IEEE Standard C57.91-1995.
    3. 3)
      • H. Rahim .
        3. Rahim, H.: ‘Transformer life assessment-electrical paper insulation degradation study of aged power transformer using furanic compound analysis technique’, 2006.
    4. 4)
      • A.K. Mehta , R. Naresh , S. Chauhan .
        4. Mehta, A.K., Naresh, R., Chauhan, S.: ‘Development of a novel dual temperature model for insulation aging in oil immersed transformers’, IEEE Trans. Dielectr. Electr. Insul., 2015, 22, (5), pp. 27232735.
        . IEEE Trans. Dielectr. Electr. Insul. , 5 , 2723 - 2735
    5. 5)
      • I. Hohlein , A.J. Kachler .
        5. Hohlein, I., Kachler, A.J.: ‘Aging of cellulose at transformer service temperatures. Part 2: Influence of moisture and temperature on degree of polymerization and formation of furanic compounds in free-breathing systems’, Electr. Insul. Mag., 2005, 21, (5), pp. 2024.
        . Electr. Insul. Mag. , 5 , 20 - 24
    6. 6)
      • A.M. Emsley , X. Xiao , R.J. Heywood .
        6. Emsley, A.M., Xiao, X., Heywood, R.J.: ‘Degradation of cellulosic insulation in power transformers: Part 3: Effects of oxygen and water on aging in oil’, IEE Proc. Sci. Meas. Technol., 2000, 147, (3), pp. 115119.
        . IEE Proc. Sci. Meas. Technol. , 3 , 115 - 119
    7. 7)
      • W.U. Guangning .
        7. Guangning, W.U., et al: ‘Experimental study on further thermal aging of transformer oil-paper insulation by organic acid catalysis’, High Voltage Eng., 2015, 41, (3), pp. 832839.
        . High Voltage Eng. , 3 , 832 - 839
    8. 8)
      • L.E. Lundgaard , W. Hansen , D. Linhjell .
        8. Lundgaard, L.E., Hansen, W., Linhjell, D., et al: ‘Aging of oil-impregnated paper in power transformers’, IEEE Trans. Power Deliv., 2004, 19, (1), pp. 230239.
        . IEEE Trans. Power Deliv. , 1 , 230 - 239
    9. 9)
      • Y. Lijun . (2009)
        9. Lijun, Y.: ‘Study on aging characteristics of oil-paper in transformer and its lifetime estimation method’ (Chongqing University, Chongqing, China, 2009).

Related content

This is a required field
Please enter a valid email address