Analysis of partial discharge acoustic wave propagation in a model transformer

The focus of acoustic partial discharge measurements is based on a partial discharge source location, and therefore knowledge of the acoustic signal propagation path is important. Numerical simulation of wave propagation in a model transformer is carried out to aid in the interpretation of the laboratory measurements in as far as the delay time of the various peaks is concerned. The simulated signals and the experimentally measured signals are in good agreement. We are able to determine the signal propagation path and to explain the waveform profile depending on the position of the acoustic emission sensors attached to the model transformer tank wall. The numerical simulation is carried out by solving the three dimensional (3D) wave equation using the finite-difference method. Of particular interest are the boundary conditions and choice of grid size to minimize the dispersion error.