Acoustic Monitoring of Partial Discharges: Differentiating Corona and Surface Discharges Using Ultrasonic Methods

Abstract

The measurement and monitoring of partial discharges (PD) have become increasingly important due to the rapid rise of new technologies that increase the frequency of PD occurrences in electrical equipment, where such phenomena were previously absent or limited. This effect directly impacts the lifespan and reliability of devices, raising the need for timely diagnostics for their detection. This study focuses on the detection of partial discharges using acoustic methods, with particular attention given to the use of ultrasonic microphones. The aim of this work was to analyze the acoustic emission signals generated by partial discharges, such as corona and surface discharges, and evaluate how their frequency spectra can be used to distinguish between these types of discharges.For the measurement of partial discharges, an ultrasonic microphone was used to record the acoustic signals generated by discharges in the tested materials. The signal was then processed using FFT analysis. This process provides a detailed overview of the frequency components of the acoustic emissions, which are characteristic of various types of partial discharges, such as corona and surface discharges for different materials. Key frequency bands were identified that correlate with the intensity and type of discharges, enabling their effective differentiation.