Effect of Hydrostatic Pressure on the Propagation of Partial Discharge Acoustic Signals in Transformer Oil

Abstract

In this research article an attempt is made to investigate the effect of hydrostatic pressure on the propagation behavior of Partial Discharge (PD) Acoustic Emission (AE) signals in a simple experimental tank. A mathematical model has been developed in the form of Partial Differential Equations (PDEs) for PD acoustic wave propagation in transformer oil in a steel tank. A Finite Element Analysis tool (FEMLAB), has been used to simulate the propagation of the acoustic waves. The simulation results show that the speed of the acoustic signal varies with the depth of the source location demonstrating hydrostatic pressure affects AE wave propagation. Furthermore, the effect of hydrostatic pressure was investigated and conformed experimentally. It is concluded that the propagation speed is not constant within the tank and increases with tank depth. If the effect of increased acoustic velocities due to hydrostatic pressure is ignored then the possibility of practical PD location algorithms inferring the incorrect location in high voltage assets, such as oil filled transformers, will be increased significantly.