What is the most commonly used cooling method for transformers?

The most commonly used cooling method for transformers is oil cooling. This method utilizes oil to absorb heat generated during the operation of the transformer. Oil has excellent thermal conductivity, allowing it to efficiently transfer heat away from the transformer's core and windings. Additionally, this cooling method also provides electrical insulation, which is crucial for the safe and efficient operation of transformers.

Oil-filled transformers are prevalent, particularly in large power transformers, because they can handle substantial power loads and prolonged operation without overheating. The oil not only cools the system but also serves as a dielectric, which helps to prevent arcing and maintain electrical integrity.

While air, water, and gas cooling methods are also used in specific applications or for certain types of transformers, they are not as universally adopted for large-scale power transformers as oil cooling is. Air cooling is limited in its capacity to handle high loads, water cooling can introduce risks related to corrosion and environmental concerns, and gas cooling, although effective in certain applications, is not as widely deployed as oil. Thus, oil cooling remains the most common and reliable method for managing the thermal performance of transformers.