Trends in Power Transformer Diagnostic Techniques

Power transformers are vital in energy delivering and distributing. Their reliability is a significant guarantee for safe and stable operation of any power grid. Any power transformer outage has a dramatic financial consequence not only for utilities but also for interconnected customers. It is therefore of utmost importance to detect incipient failure to avoid catastrophic blackouts. The Achilles’ heel of these important machines is their insulation system, made of oil and cellulosic paper. Since the service reliability of these machines largely depends upon the condition of their internal insulation system, number of methods were developed/improved to understand and monitor their degradation. During the last decades, ways to prevent electrical outages, extend their life expectancy and improve preventive maintenance procedures have become increasingly important. Varieties of electrical and physicochemical diagnostic techniques were developed so far for insulation condition monitoring of power transformers. This lecture presents a comprehensive review of transformers’ insulation condition assessment including both challenges and outlook circa 2021