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

Oil filled transformers use liquid insulation and cooling, with tanks, bushings, conservator systems, and oil treatment needs. They offer higher voltage and MVA capability and better cooling. Dry-type transformers use solid insulation and air cooling, reducing spill and some fire risks, and are often used indoors. Dry-type units can be easier to install where oil containment is difficult, but they may have lower power density and different maintenance issues like dust and ventilation. Choice depends on voltage, environment, and safety policy.