Abstract
Insulation of transformer windings may shift as a result of short circuit current or impact during transportation. The shift modifies the dielectric space between the layers of the windings and may cause an insulation breakdown, leading to a complete transformer failure. As transformers are very costly to replace, it is important that their condition determined accurately without having to dismantle the apparatus to visually inspect it. Testing of winding insulation is performed by using the standard impulse test, via applying fast Fourier transform (FFT) to analyze the transformer state (healthy or faulty) in the frequency domain, as a Transfer Function (TF). Nonetheless, one of the shortcomings of the FFT is that it cannot be used with nonstationary signals. Voltage and current waveforms in the transformer are treated as nonstationary signals, especially when there is a fault. In addition, FFT does not give any information on the time at which a frequency component occurs. To obtain better signature analysis and to increase the detection sensitivity, this paper suggests a new method using Short Time Fourier Transform (STFT) in the transfer function analysis. It is hoped that this high resolution method will help to reduce the subjective judgments of technicians when making decisions about changes in the winding structure of the transformer.
| Original language | English (US) |
|---|---|
| Title of host publication | 2005 IEEE Power Engineering Society General Meeting |
| Pages | 1855-1862 |
| Number of pages | 8 |
| Volume | 2 |
| State | Published - 2005 |
| Event | 2005 IEEE Power Engineering Society General Meeting - San Francisco, CA, United States Duration: Jun 12 2005 → Jun 16 2005 |
Other
| Other | 2005 IEEE Power Engineering Society General Meeting |
|---|---|
| Country | United States |
| City | San Francisco, CA |
| Period | 6/12/05 → 6/16/05 |
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Keywords
- EMTP
- Faults
- Signature analysis
- Time-frequency representation
- Transformer
ASJC Scopus subject areas
- Engineering(all)
Cite this
Transfer Function analysis using STFT for improvement of the fault detection sensitivity in transformer impulse test. / Al-Ammar, Essam; Karady, George G.
2005 IEEE Power Engineering Society General Meeting. Vol. 2 2005. p. 1855-1862.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Transfer Function analysis using STFT for improvement of the fault detection sensitivity in transformer impulse test
AU - Al-Ammar, Essam
AU - Karady, George G.
PY - 2005
Y1 - 2005
N2 - Insulation of transformer windings may shift as a result of short circuit current or impact during transportation. The shift modifies the dielectric space between the layers of the windings and may cause an insulation breakdown, leading to a complete transformer failure. As transformers are very costly to replace, it is important that their condition determined accurately without having to dismantle the apparatus to visually inspect it. Testing of winding insulation is performed by using the standard impulse test, via applying fast Fourier transform (FFT) to analyze the transformer state (healthy or faulty) in the frequency domain, as a Transfer Function (TF). Nonetheless, one of the shortcomings of the FFT is that it cannot be used with nonstationary signals. Voltage and current waveforms in the transformer are treated as nonstationary signals, especially when there is a fault. In addition, FFT does not give any information on the time at which a frequency component occurs. To obtain better signature analysis and to increase the detection sensitivity, this paper suggests a new method using Short Time Fourier Transform (STFT) in the transfer function analysis. It is hoped that this high resolution method will help to reduce the subjective judgments of technicians when making decisions about changes in the winding structure of the transformer.
AB - Insulation of transformer windings may shift as a result of short circuit current or impact during transportation. The shift modifies the dielectric space between the layers of the windings and may cause an insulation breakdown, leading to a complete transformer failure. As transformers are very costly to replace, it is important that their condition determined accurately without having to dismantle the apparatus to visually inspect it. Testing of winding insulation is performed by using the standard impulse test, via applying fast Fourier transform (FFT) to analyze the transformer state (healthy or faulty) in the frequency domain, as a Transfer Function (TF). Nonetheless, one of the shortcomings of the FFT is that it cannot be used with nonstationary signals. Voltage and current waveforms in the transformer are treated as nonstationary signals, especially when there is a fault. In addition, FFT does not give any information on the time at which a frequency component occurs. To obtain better signature analysis and to increase the detection sensitivity, this paper suggests a new method using Short Time Fourier Transform (STFT) in the transfer function analysis. It is hoped that this high resolution method will help to reduce the subjective judgments of technicians when making decisions about changes in the winding structure of the transformer.
KW - EMTP
KW - Faults
KW - Signature analysis
KW - Time-frequency representation
KW - Transformer
UR - http://www.scopus.com/inward/record.url?scp=27144487426&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=27144487426&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:27144487426
SN - 078039156X
SN - 9780780391567
VL - 2
SP - 1855
EP - 1862
BT - 2005 IEEE Power Engineering Society General Meeting
ER -