Recent progress in diagnosis of transformers using non-conventional partial discharge measurements

This paper deals with recent progress in diagnosis of oil-filled transformers using non-conventional partial discharge (PD) measurements; i.e. acoustic signal detection method and electromagnetic wave detection method. To enhance the reliability of the diagnosis, such as precise PD location identification and increase of the PD detection sensitivity, acoustic and electromagnetic signal propagation in a transformer model are investigated using numerical calculation by FEM(finite element method) and FDTD (finite difference time domain) with the transformer internal structure and components considered. From these simulation results on the propagation properties, enhancement of location precision of PD source and detection sensitivity is discussed.