Fundamental study on partial discharge induced acoustic wave propagation in simulated transformer composite insulation system

We aim to establish the advanced diagnostic technique for electric power transformer using online partial discharge measurement. This paper deals with propagation characteristic of acoustic waves emitted by partial discharges, or PDs in a simulated transformer which was composed of pressboard and mineral oil. PDs were generated by a rod-insulator-rod electrode immersed in mineral oil. The acoustic waves were measured with three AE sensors installed on the outside surface of the simulated transformer. PD-induced acoustic waves were also measured through pressboard, with attenuation characteristic of the acoustic waves considered. Numerical simulation allows us to understand the propagation characteristics of acoustic waves.