What maintenance tasks apply to oil filled transformers?

Typical tasks include oil level checks, leak inspections, bushing and gasket inspection, breather maintenance, cooling system checks, temperature indicator verification, and periodic oil sampling for BDV, moisture, acidity, IFT, and DGA. Depending on condition, tasks may include filtration, dehydration, oil regeneration, tightening connections, infrared thermography, and electrical tests. Good records and trend analysis are essential to schedule interventions before failures.