Which method is not used to cool transformers?

Transformers are critical components in electrical systems, and their operation generates heat that needs to be managed to ensure efficient function and longevity. Various methods are employed to cool transformers to prevent overheating, and these include oil cooling, pumped convection, and forced ventilation.

Oil cooling involves immersing the transformer in oil that absorbs and dissipates heat. The oil's properties allow it to effectively transfer heat away from the internal components. Pumped convection is a method where the oil or coolant is circulated through the transformer using pumps, enhancing the cooling effect by increasing the rate of heat transfer. Forced ventilation involves using fans or blowers to direct air over the transformer's surface, helping to carry away heat generated during operation.

On the other hand, solar heating does not serve as a cooling method; rather, it is a means of harnessing solar energy for heating applications. In the context of transformers, solar heating is not utilized, as it would increase the temperature rather than decrease it. Therefore, recognizing the roles of various cooling techniques clarifies why solar heating is not a method used for cooling transformers.