What are the key differences between oil filled vs dry type transformers?

Oil filled transformers use liquid insulation and cooling, supporting higher voltage and MVA ratings, better heat dissipation, and longer insulation life. Dry type transformers use solid insulation and air cooling, eliminating oil spill risk and simplifying indoor installation. Oil filled units require containment, oil testing, and fire protection, while dry type units need controlled ventilation and may have higher noise. Grid level transmission strongly favors oil filled designs, while dry type units are common in buildings and indoor industrial facilities.