What is the permissible water content in transformer oil?

The permissible water content in transformer oil is typically less than 30 parts per million (ppm). Maintaining this low level of water content is crucial, as excessive moisture can lead to the degradation of the oil’s insulating properties and promote the formation of acids, which can damage the transformer. Regular testing and monitoring of the water content in transformer oil are essential for ensuring the longevity and reliability of power transformers.