Investigating the Emitted Signals of Partial Discharges for Diagnostic Applications in High Voltage Equipment

The goal of this paper is to present the time and frequency domain behavior of the emitted electromagnetic signals of the three main types of partial discharges (corona, void and surface discharges) in the VHF and partially the UHF range, and to find the characteristic properties of these signals. A noise and interference free environment was used to measure the undistorted emitted signals of the discharge sources. The individual discharge pulses were investigated in both time and frequency domain, followed by the phase resolved investigation of their time domain behavior. A part of these results showed similarities, making it easier to use these properties for creating a universal digital filtering module. The other part of the results showed significant characteristic differences that were in-line with the traditional measurement results of the literature and can be used for signal separation. The results of this paper can be utilized in the development of the signal processing module of an on-site, real-time partial discharge location approximation system.