Application research based on modern-technology for transformer Health Index estimation

Diagnosis of power transformers becomes important due to the age of the transformer in service. Diagnosis methods can be separated in integral or differential methods. This paper describes a realistic Health Index formulation method for power transformers using readily available data. The method considers practical limitations on obtaining data, and the possible constraints on the parameters. This Health Index estimation considers not only typical test results such as dissolved gas analysis (DGA), oil quality, furan, and power factor, but also other parameters such as frequency response analysis (FRA), turn ratio, tap changer and bushing condition, physical observations, load history, maintenance work orders, and In-Service age of transformer. The calculation includes condition ratings, weighting factors, and assigned scores for specific condition parameters. By using a multi-criteria analysis approach, the method combines the various factors into a condition-based Health Index.