One-Step Insulating Oil Reclamation by PVDF/PTFE Composite Nanofibers

Insulating oil is indispensable cooling impregnation and isolation agent for oil-filled electrical equipment, such as power transformers. The aging byproducts, i.e., water and organic acids, impose a serious threat to these expensive transformers. Insulating oil reclamation is a complicated process. In this article, a polyvinylidene fluoride (PVDF) polymer with polytetrafluoroethylene (PTFE) additive composite nanofiber membrane is synthesized for insulating oil reclamation with high efficiency. The reclamation and dielectric performance of the PVDF/PTFE nanofiber membrane is evaluated by the acid value, microwater (MW) contents, and ac breakdown voltage of the treated oil. The results show that the nanofiber membrane filtration rate toward acetic acid and MW is 69.4% and 76.0%, respectively. Moreover, the dielectric loss factor and relative permittivity of treated oil decrease significantly at low frequencies, and the breakdown voltage is increased from 21.8 to 65.2 kV. The PVDF/PTFE composite nanofiber membrane has removed organic acid and MW effectively, and it provides a more practical method for insulating oil reclamation.