Online IFRA for Identification of Power Transformer Faults Based on Pulse Compression Method

Abstract—The most accurate method, recommended for the energy transformers diagnostic, is the Frequency Response Analysis (FRA), in the form of two implementations, Impulse-Frequency Response Analysis (IFRA), and Sweep-Frequency Response Analysis (SFRA). Both implementations have their own advantages, as well as difficulties, when applied to a transformer without disconnecting them from the load. Till now, there is no clear consensus which of them is better. However, for the case of the IFRA method applied to distribution transformers, difficulties about signal injection on low voltage side can be easily overcome if the pulse compression method is used for generation of testing excitations. Using pulse compression method, other obstacles connected to high voltage application is avoided, and many signal processing advantages that exist in various system identification methods can be implemented. On that way on-line IFRA can be method of choice for preventive diagnostic of distribution transformers