A study of partial discharge acoustic signal propagation in a model transformer

Many researchers have studied the partial discharge (PD) source location in transformers using acoustical methods. However, most of these studies have treated the transformer as a homogeneous medium, thus rendering the location of discharges inside the transformer winding difficult. In this paper, the authors present a 3-D computer simulation of the PD acoustic signal propagation path in an attempt to locate the PD source. The computer simulation is in agreement with experimental data obtained from the laboratory. Further, the effect of the real transformer tank on the acoustic signal is studied with an aim of distinguishing the various frequency dependent signal components that are detected by an acoustic emission (AE) sensor. This is particularly important in explaining the acoustic coupling between oil and transformer tank material and for determining the propagation velocities when determining the PD source location