what is the purpose of breather in oil transformer?

The purpose of a breather in an oil transformer is to maintain the quality of the insulating oil by preventing moisture ingress. It typically contains silica gel, which absorbs moisture from the air entering the transformer as the oil expands and contracts due to temperature changes. This moisture control is crucial, as excess water can degrade the oil’s insulating properties and lead to transformer failure. Thus, the breather helps ensure the longevity and reliability of the transformer.