On-Site Measurement of Partial Discharge: Investigating Characteristics through Rise Time Analysis

This paper describes partial discharge (PD) characteristics for on-site measurement based on rise time waveform. The frequency of partial discharges (PD) is a significant factor concerning electrical insulation. The implications of this kind of PD characteristics are becoming increasingly important with the rapid development of the detection of PD signals in medium voltage. The rise times characteristics are used in insulation condition monitoring to keep getting earlier information about the insulation condition of the high voltage or medium voltage equipment. Currently, there is minimal research working on the characteristics especially rise time and due to this, it needs to further develop comprehensive characteristics of PD detection at such extreme conditions. An on-site PD measurement using Rogowski coil (RC) and MATLAB analysis focusing on rise times is presented here. Measurement was set up based on the IEC60270 standard and the circuit in the standard is followed. Insulation used in this work is XLPE type under 11 kV voltage stress and there were eight locations were performed in order to get a clear picture of the pattern. The overall result indicates that the rise times range is between 1.5 and 5 ns. The impact of rise time characteristics on the PD signal based on the real measurement is huge since the maintenance unit can perform measurement in a short time compare to the previous method. Specifically, the total number of PD measurement and severity range were shown with cable length. The rise time pattern always provide different value depending on level severity and frequency. However, when combining the result rise time from 8 substations measured, it provides a significant result. The finding is valuable for future PD measurement and detection at the site when the operator directly focuses on the range value to identify PD signals.