Partial discharge detection and localization in power transformers

Acoustic partial discharge (PD) detection method has been developed as an important non-destructive testing technique adopted for monitoring the material processes and for testing, detection, and characterization of any defect in an electrical apparatus like power transformers. This method has advantages like the placement of several sensors on the outside of the tank allows a localization of PD source and measurements can be performed on-line and on-site. The paper describes a combination of UHF/electrical and acoustic method because combination of methods more increases plausibility of PD activity than pure acoustic method. This method can find PD sources with higher sensitivity especially for hidden PD defects. An experimental validation has been done on the transformer insulation model using an acoustic sensor at first in this paper. The study was complemented with measurements on transformers in test field.