What are the advantages and disadvantages of oil cooled transformers?

Advantages include strong insulation performance, efficient cooling, compact high MVA designs, and proven field reliability with established diagnostics like DGA. Disadvantages include spill and fire risk, environmental compliance requirements, the need for oil handling equipment, and maintenance for leaks, breathers, and moisture control. In some indoor settings, oil may be restricted or require costly containment and fire mitigation compared to dry type alternatives.