Acoustic Emission Properties of Partial Discharges in the time-domain and their applications

Abstract: A partial discharge (PD) is an unwanted phenomenon in electrical equipment. Therefore it is of great importance to identify different types of PD and assess their severity. This thesis investigates the acoustic emissions associated with PD from different types of sources in the time-domain and based on these results a low-cost detection system is designed, built and verified against much more expensive commercially available sensor platforms. The results are promising both for the detection of different types of PD and their classification. The lowcost detection system shows equal usefulness as commercially available systems and the system is also compared against other systems for detection. Also some investigation is carried out concerning the nature of the ultrasounds emitted by PD. The results from these experiments indicate that a description with the classical wave equation is inadequate. In order to explain the frequency content of acoustic PD signals at different distances away from the source, a more complex description in the form of nonlinear acoustic equations may be more accurate.