Effect of sensor position on the measurement of acoustic wave produced by partial discharges

Abstract

This paper presents the finite element method (FEM) simulation of the propagation, measurement and evaluation of the time of arrival (TOA) of the acoustic wave created by a partial discharge (PD) in a transformer model using COMSOL multiphysics software. This model is a flat tank filled with an insulating liquid. In addition, 8 acoustic probes placed on one of the outer faces of the tank provide information on acoustic pressure levels for specific values of angles of incidence of the acoustic signal. The addition of signal transmission zones for each of the probes makes it possible to define precise paths for the acoustic signal, enabling the TOA of the acoustic wave to be evaluated for each path. The results of this study show that for angular values less than 40°, the error on the TOA is practically zero, but for values greater than 40° this error increases exponentially with the angle. This means that for an angle of 40.41° the error is 6μs, corresponding to 1.7%, and for an angle of 71.70° the error is 332μs, corresponding to 40.3%. This highlights the optimal nature of the choice of sensor position for locating partial discharge.

Keywords

• Partial discharge
• Acoustic wave
• Power transformer
• Finite element method
• COMSOL multiphysics
• Time of arrival