What are the common cooling methods for oil-immersed transformers?Oil-immersed natural cooling (ONAN)Principle: Relies entirely on natural forces for heat dissipation. After absorbing heat, transformer oil naturally rises, transferring heat to the air through the tank walls and radiators. Natural co

Air coolers on the transformer tankPhysical connection method: The cooler is directly secured to the side or top wall of the transformer tank via bolts or welding. Its heat exchange surface closely adheres to the tank wall (with thermal grease applied in some areas to enhance heat transfer), forming