What type of cooling method is commonly used for large transformers?

Oil immersion cooling is commonly used for large transformers because it provides efficient heat dissipation, is effective at regulating temperature, and protects the electrical components from moisture and contaminants. In large transformers, the oil serves not only as a coolant but also as an insulator, which helps maintain safe operational voltage levels. This method enables large transformers to handle high power levels while effectively managing the heat generated during operation, thus enhancing performance and reliability.

Unlike air cooling, which may not be sufficient for the high temperatures associated with larger units, oil immersion offers a much greater thermal mass and heat transfer capability. Water cooling, while effective in some industrial applications, is generally less common for transformers due to the risk of electrical shorts and the need for additional components to handle water. Natural convection cooling is typically reserved for smaller transformers where less robust cooling requirements exist, as it relies on the natural movement of air to dissipate heat, which may not be adequate for larger units.