Onsite non-invasive partial discharge detection and location system for underground cables using customized envelope detection

Abstract

Partial Discharge (PD) can be considered as an insulation defect. Magnitude and frequency of the PDs provide information about the insulation health of the underground cables. Therefore, detection and location of PD are particularly crucial for mission-critical cable feeders. Hence, accurate PD location estimation increases efficiency by reducing repair costs, time spent on operation, and crew dispatching. Commercial PD measurement devices, generally, have high costs and require expert knowledge. Further, signal processing of the raw PD data is not published. This study propose onsite partial discharge detection and location system for underground cables. The raw PD data taken from the HFCTs which connect to the cable sheaths rather than the phase’s. Thus, non-invasive measurements are provided. The magnitude and location of the PDs are obtained by using a complex baseband digital signal processing algorithm with an customized envelope detection technique. The effectiveness of the proposed customized envelope detection technique is demonstrated by simultaneous onsite measurements with a commercial PD test device. The result of the study is compatible with the results obtained with the commercial PD test device. Another important results is that the PD detection and location detection is conducted on relatively longer XLPE cable (2832 meters) compared to the existing literature. Therefore, it can be used for the live PD tests by distribution system operators.