Transformer frequency response: A new technique to analyze and distinguish the low-frequency band in the frequency response analysis spectrum

Smart monitoring applications in all aspects of power systems are becoming increasingly popular because of the indirect effect on energy management and the smart grid. In this regard, high voltage equipment monitoring and real-time assessment are critical. Among these evaluations, transformer life and condition assessment has been considered for many years [1], [2]. Currently, advanced methods such as transfer function measurement are employed to determine the transformer condition [3]. Transfer function measurement is generally used for black box system identification [4]. This measurement might be implemented in the time domain as an impulse response or in the frequency domain using a swept signal; the latter approach is commonly called frequency response analysis (FRA) [5].