Studying the Loss of Life of Natural-Ester-Filled Transformer Insulation: Impact of Moisture on the Aging Rate of Paper Articles uri icon

publication date

  • January 2017

start page

  • 15

end page

  • 23


  • 1


  • 33

International Standard Serial Number (ISSN)

  • 0883-7554


  • Moisture is one of the most harmful agents for transformer solid insulation. The catalyzing effect of moisture on the degradation process of paper and pressboard has been studied by several authors, who developed models which they used to estimate how the aging process would be accelerated in the presence of water [1]-[5]. In [2] and [3] Lelekakis et al. reported the results of an experimental study in which samples with different moisture contents were aged in the presence of mineral oil (MO). In [3] an equation to determine the reduction of service lifetime of insulation subjected to increased temperature and with increased moisture content is proposed.


  • Industrial Engineering
  • Materials science and engineering


  • oil-paper insulation; natural ester; transformer; moisture in paper; accelerated aging; transesterification; hydrolysis; power transformers; oxygen concentration; oil/paper system; part 2; cellulose; degradation; oil