On the Range of Influence of Magnetic Core on Frequency Characteristics of Transformers

Abstract

The main problem in interpreting the results of the sweep frequency response analysis (SFRA) diagnostic tests is the lack of measurement information on a specific type of transformer failure. Including therefore the so-called "Fingerprint" method, in which the characteristics of a working device are compared with the tested device data. This way, a possible range of diagnostic changes is obtained, but without a specific location of the damage. Modeling transformers over a wide frequency range can help in this. Measurements with reference coils and transient recovery voltage (TRV) indicator show need of include influence of magnetic core on frequency characteristics. One should also pay attention to the influence of the magnetic core on the obtained transformer frequency characteristics.