Abstract:
Insulation is considered an important and critical part of power and distribution transformers as any weakness of the insulation will result in the failure of these transformers. To ensure reliable operation of transformers in a power system, they are checked for their insulation integrity. For this purpose the transformers are undergone high voltage impulse testing. In this test a standard 1.2/50 µs high-voltage impulse is applied and waveforms of voltage and current are recorded. In case of major faults there will be a considerable deviation between healthy and faulty waveforms so the detection of such faults is an easy task. It can be done by the visual inspection of the time domain waveforms of the impulse voltage and neutral current. But in case of a minor fault e.g., a short circuit between two adjacent turns of the winding, time domain waveform gives no useful information. To enhance the fault-detection sensitivity, impulse waveforms are analyzed in frequency domain. For this purpose many frequency response analysis techniques have been reported in the past few years. Analysis of only applied impulse voltage waveform does not help much in the detection of minor faults. So it is a common practice to analyze the applied impulse voltage along with the resultant current. The fault detection sensitivity increases further if applied impulse voltage is analyzed along with the resultant current on the other side of transformer. In this research work a technique will be developed, based on the analysis of transadmittance (ratio of primary current to secondary voltage in frequency domain), to detect and identify the fault in a distribution transformer.
Page(s):
3-5
DOI:
DOI not available
Published:
Journal: New Horizons: Journal of the Institution of Electrical & Electronics Engineers Pakistan, Volume: 75, Issue: 0, Year: 2012