What maintenance practices are required to keep transformer oil in good condition?

Good practices include maintaining seals and breathers, controlling moisture ingress, periodic oil sampling with clean methods, and trending key parameters like DGA, moisture, BDV, acidity, and tan delta. When indicators worsen, utilities use online or offline filtration, vacuum dehydration, or regeneration to remove water, gases, and acids. Cooling system health matters too, because high temperatures accelerate oxidation and sludge formation. Regular inspections of bushings, gaskets, radiators, and oil level instruments help prevent small leaks from turning into major contamination events.