What are the effects of polychlorinated biphenyls in transformer oil?

Polychlorinated biphenyls (PCBs) in transformer oil can have several detrimental effects. They can degrade the insulating properties of the transformer oil, leading to increased risk of electrical failure. Additionally, PCBs are toxic and pose environmental hazards, as they can accumulate in the ecosystem. Their presence in transformer oil can also complicate regulatory compliance and necessitate costly remediation efforts, impacting the overall operation and maintenance of power transformers.