A comparison of the formation of bubbles and water droplets in vegetable and mineral oil impregnated transformer paper

Caesar Yudha Perkasa, Nick Lelekakis, Tadeusz Czaszejko, Jaury Adi Wijaya, Daniel David Martin

Research output: Contribution to journalArticleResearchpeer-review

43 Citations (Scopus)


Bubble formation from paper insulation during overload is important to understand because it can cause a transformer to fail. This phenomenon has been investigated in a mineral oil-paper system, but not in vegetable oil. This study investigated bubble formation during overload in a vegetable oil impregnated paper system and the results were compared to a mineral oil (Shell Diala B) which was studied previously using similar test equipment and method. The limiting hot-spot temperatures for bubbles and water droplets in vegetable oil for paper with water content between 1 - 6 % were determined. The water content of paper measurement which is critical when setting the winding temperature limit was evaluated using both a moisture sensor and Karl-Fischer titration method.
Original languageEnglish
Pages (from-to)2111 - 2118
Number of pages8
JournalIEEE Transactions on Dielectrics and Electrical Insulation
Issue number5
Publication statusPublished - 23 Oct 2014


  • power transformer insulation
  • vegetable oil
  • bubble formation
  • Moisture content
  • overload

Cite this