Why is mineral oil widely used in transformers?

Mineral oil is widely used because it offers a proven balance of high dielectric strength, effective heat dissipation, chemical stability, availability, and cost efficiency. It is compatible with cellulose insulation, easy to process and regenerate, and well covered by international standards. Utilities value its predictable aging behavior, established maintenance practices, and broad supplier base, making mineral oil the default choice for most power and distribution transformers.