Fluorinated and Charged Non-woven Polypropylene Electret Fiber Membrane: A Novel Way in Transformer Oil Regeneration

The regeneration of transformer oil is a trending topic in the dielectric research field. However, the normal way of regeneration requires high cost and complicate process. In this paper, the non-woven polypropylene (PP) electret films were modified by fluorination and corona method to achieve the regeneration function for transformer oil. The results show that the C-H bonds in polypropylene were replaced by C-F bonds during the fluorination process, resulting in the mean diameter of the fibers being decreased to a value of 1.7 μm. The increased roughness of the fibers leads to super hydrophobicity. Further research revealed that the insulation properties of aging oil recovered after filtration by corona charged fluorinated fiber membranes. The result is especially significant for breakdown voltage, the values of which reached half of the original insulating oil. In conclusion, the combination of fluorinating and corona charging method on PP fiber membrane shows great potential for insulation oil regeneration.