What is the appropriate oil grade for power transformers?

The appropriate oil grade for power transformers is typically defined by the IEC 60296 standard, which specifies mineral insulating oils. These oils are classified based on their properties, such as viscosity and flash point. Common grades include mineral oil with a high dielectric strength and low viscosity, ensuring effective insulation and cooling. Additionally, synthetic oils may be used for specific applications requiring enhanced thermal stability and fire resistance.