What is the process of transformer oil re-refining?

The process of transformer oil re-refining involves several stages to restore used transformer oil to its original quality. Initially, the oil is filtered to remove particulate contaminants. Next, it undergoes vacuum distillation to separate lighter fractions and remove moisture. Chemical treatments may be applied to neutralize acids and remove polar compounds. Finally, the re-refined transformer oil is tested for dielectric strength and other properties to ensure it meets industry standards before reuse in power transformers.