Simulation Study on Ultrasonic Signal Propagation Characteristics of Partial Discharge in Transformers

Abstract

Ultrasonic detection method is widely used to detect partial discharge (PD) in transformers because of its anti-electromagnetic interference and high sensitivity. It is of great significance to understand the sound wave propagation characteristics in transformers for ultrasonic signal detection and sensor arrangement optimization. In this paper, based on the finite element method, the ultrasonic signal propagation characteristics of PD in transformers are numerically studied, and the acoustic wave propagation characteristics in transformers are analyzed. The calculation results show the following facts: the multiple reflections of sound waves have a significant influence on the sound field distribution in transformers, and the sound pressure drops to 40Pa at 2500 μs; The absorption coefficient of the transformers has little influence on sound wave propagation, but when the absorption coefficient of the wall increases from 0.2 to 0.8, the pulse response time of receivers will be less than 1/2 of the original, and the arrival time difference in the area where the direct wave signal cannot be detected will be increased. When optimizing the sensor layout, priority should be given to the position with few obstacles, such as the area facing the winding gap.