Extended Use for the Frequency Response Analysis: Switching Impulse Voltage Based Preliminary Diagnosis of Potential Sources of Partial Discharges in Transformer  
[PERSON]  
1 Department of EEE, School of Electrical & Electronics Engineering, SASTRA Deemed University, Tamilnadu 613401, India; [EMAIL_ADDRESS] (K.A. ); [EMAIL_ADDRESS] (B.M. ); [EMAIL_ADDRESS] (R.R.) [PERSON]  
1 Department of EEE, School of Electrical & Electronics Engineering, SASTRA Deemed University, Tamilnadu 613401, India; [EMAIL_ADDRESS] (K.A. ); [EMAIL_ADDRESS] (B.M. ); [EMAIL_ADDRESS] (R.R.) [PERSON]  
1 Department of Electrical Power Engineering, Faculty of Mechanical and Electrical Engineering, Tishreen University, Lattakia 2230, Syria  
1 Department of Management and Innovation Systems, University of Salerno, 84084 Salerno, Italy  
1 Department of EEE, School of Electrical & Electronics Engineering, SASTRA Deemed University, Tamilnadu 613401, India; [EMAIL_ADDRESS] (K.A. ); [EMAIL_ADDRESS] (B.M. ); [EMAIL_ADDRESS] (R.R.) [PERSON]  
1 Department of EEE, School of Electrical & Electronics Engineering, SASTRA Deemed University, Tamilnadu 613401, India; [EMAIL_ADDRESS] (K.A. ); [EMAIL_ADDRESS] (B.M. ); [EMAIL_ADDRESS] (R.R.) [PERSON]  
1 Department of EEE, School of Electrical & Electronics Engineering, SASTRA Deemed University, Tamilnadu 613401, India; [EMAIL_ADDRESS] (K.A. ); [EMAIL_ADDRESS] (B.M. ); [EMAIL_ADDRESS] (R.R.) [PERSON]  
2 Department of Electrical Power Engineering, Faculty of Mechanical and Electrical Engineering, Tishreen University, Lattakia 2230, Syria  
2 Department of Management and Innovation Systems, University of Salerno, 84084 Salerno, Italy  
2 Department of Electrical Power Engineering, Faculty of Mechanical and Electrical Engineering, Tishreen University, Lattakia 2230, Syria  
2 Department of Management and Innovation Systems, University of Salerno, 84084 Salerno, Italy
interference (EMI) and electromagnetic compatibility (EMC) of DC machines, and demonstrated the usefulness of the frequency domain analysis in performance characteristic analysis [9; 10]. Literature also reports on the factors influencing the sensitivity of FRA, different transfer function approaches, and comparison between Lightning impulse voltage-based Frequency Response Analysis (LFRA) and Sweep sinusoidal voltage-based Frequency Response Analysis (SFRA) [11; 12; 13]. The SFRA approach is standardized, so that most of the recent works were carried out based on the sweep frequency response approach with different transfer functions [14; 15; 16]. However, for Impulse-based Frequency Response Analysis (IFRA), the same methodology and transformer connections can be applied, as explained in literature [14]. The conventional SFRA and LFRA approaches use the test signals of a low magnitude that are found to be sufficient for the diagnosis of mechanical displacement of windings, inter-turn shorts, and magnetic core issues. As per IEC 60270(2000), partial discharge (PD) is a localized electrical discharge that only partially bridges the insulation. In general, Partial discharges are a consequence of local electrical stress concentrations in the insulation [17]. Across a potential source of PD (like Void, air or oil bubble contained inside transformer insulation), a discharge can happen when the potential across the same in the form of alternating/direct/impulse voltage exceeds the discharge inception level. Several literature are available for the diagnosis of PD, such as power frequency-based PD test, the ultrahigh frequency (UHF) method, acoustic emission (AE) method, and dissolved gas analysis (DGA). Most of the conventional tests use power frequency as the test signal. For example, [PERSON] et al. demonstrated the PD diagnosis in insulating oil across needle-plane, plane-plane and wire wire electrodes through frequency analysis of the acoustic signal [18]. However, for the diagnosis of the voltage-dependent problems, like PD, the conventional low magnitude SFRA and LFRA are not suitable.