Current Status and Future Trends in Frequency-Response Analysis With a Transformer in Service

This paper presents the current status and future trends in the application of the frequency-response analysis (FRA) technique with the transformer in service (online) through bibliographic review and analysis. As a result, three basic stages of the online FRA test have been identified and defined: 1) injection and excitation signal measurement; 2) recording, filtering and processing of measured signals; and 3) curve analysis and interpretation. This work presents an overview of the online FRA technique, useful for subsequent research in this area.