Detection of temporary faults during impulse tests using wavelets

The impulse test on power transformers simulates the conditions that exists in service when a transformer is subjected to an incoming high voltage surge due to lightning or other disturbances on the associated transmission line. There have been several studies on the application of wavelets to identify faults during impulse testing. Most of these studies have utilized simulated waveforms in which the fault is introduced by a suitable mathematical model. In this paper the authors have used a new technique to simulate such faults. Experimentally obtained waveforms are used to investigate the suitability of wavelets to detect faults during impulse testing and this paper presents preliminary results of this research work.