3-D Simulation and Modelling of Acoustic Signals from Partial Discharge Activity

This paper presents a 3D simulation study of the basic propagation of partial discharge (PD) acoustic emission (AE) signals from structures akin to high voltage equipment such as switchgear. Partial differential equations (PDE) describing the signals have been developed and solved using Finite Element Analysis (FEA) rather than Finite Difference Time Domain (FDTD) which has been used by different authors. The study described in this paper helps to investigate the propagation behaviour of the AE waves at the interface of two different media namely oil and steel. Reflection, refraction and scattering of the PD shock waves are simulated and displayed in 3-D model. The results show that the signals can alter significantly based on the location of the PD and also the properties of the oil and steel, particularly temperature. This is a new result and particularly important in relation to the interpretation and understanding of practically measured AE PD signals. The work presented here will therefore assist in PD diagnosis and aid in understanding better the properties and characteristic of acoustic PD activity.