Diffusion Coefficient in Transformer Pressboard Insulation Part 1: Non Impregnated Pressboard Articles uri icon

publication date

  • February 2014

start page

  • 360

end page

  • 368


  • 1


  • 21

International Standard Serial Number (ISSN)

  • 1070-9878

Electronic International Standard Serial Number (EISSN)

  • 1558-4135


  • Water is harmful for transformers; the dynamic behavior of moisture influences the dielectric integrity and insulation aging in a transformer on operation. In this paper, the determination of the diffusion coefficient of moisture in transformer pressboard is tackled. This work has been focused in analyzing non oil-impregnated pressboard, so the obtained coefficient is useful for studying the processes of transformer drying in factory. Drying experiments were developed in a thermogravimetric analyzer on non-impregnated samples of pressboard subjected to different drying temperatures. The experimental conditions were simulated by means of a diffusion model implemented by means of Finite Element Method. The comparison between estimated and measured values allows drawing conclusions about the accuracy of the proposed coefficient.


  • transformer solid insulation; moisture; moisture dynamics; diffusion coefficient; pressboard