The acoustic emission (AE) technique is one of the unconventional methods of partial discharges (PDs) detection. It plays a most important role in oil-filled power transformers diagnostics because it enables the detection and online monitoring of PDs as well compared to the conventional method for PDs detection which are not suitable for on-site measurement due to electrical disturbance. In this paper, the acoustic based on piezoelectric sensor by different material is modelled in order to be able to obtain PDs signal occurred in power transformers. Modelling of a piezoelectric sensor with different material which is PZT-5H, ZnO, and AlN is approached in order to investigate the performance of resonant frequency, electric potential, and the performance in processing in order to match the range of AE detection. Piezoelectric materials have become very useful in processing devices because of their electrical-mechanical mutuality. Study was performed on frequency target of PDs should be higher and in the range of 10 kHz -300 kHz in order to prevent the power transformer from failure or breakdown and it has been found out by proven from analytical and simulation result by using the Finite Element Method (FEM). Based on this information, acoustic sensor is analyses with different types of cantilever beam and piezoelectric material and different length dimension of the beam in order to analyses the performance between them. Based on the result, the piezoelectric material that be chosen in this project is ZnO due to its high piezoelectric coupling and environmental friendly is used in order to support green technology compared to others material discussed which is harmful even though produced high performance. This detection method gave some improvement in monitoring system PD activities in the transformer's tank.
