Diagnostics and Condition Monitoring of Power Transformer

There has been growing concern by the utilities on the cost of assets and its replacements particularly those of power transformer. In this context, monitoring and onsite diagnostics are seen as a possible way of optimizing existing assets. The main driving forces are to reduce maintenance cost, to prevent forced outages with related consequential cost and to enable existing equipment work longer. Since the cost of power transformer is very high in power transmission and distribution system; it is important to develop equipment, which could aid in maintenance of power transformers. In other words, it is essential to determine the likely failures which could occur including the causes of failure. Reports available from CIGRE working groups [I] highlights the type of failures and the components involved in failure. Text I gives the components involved in failure of transformers. Failure of windings and terminals contribute to the highest percentage of failure. It is also known that failures due to design, manufacturing and materials represent some percentage of transformer loss.