Application of the online partial discharge monitoring for the EHV XLPE cable system

On-site partial discharge (PD) detection is an important way to assess the insulation conditions of the power cable system in operation. In this paper, three types of PD sensors that are used commonly during on-site detection were compared. The propagation characteristics of the PD pulse along cable system were studied, and the wavelet anti-interference technology was trial applied. The essential database of typical PD fingerprints was established with experimental results obtained from PD detection with typical defects of EHV XLPE cables and joints. Finally, an online PD monitoring system for an EHV XLPE cable system was developed. The data obtained from the system show that it is effective for finding the defects of cables and joints, and early warning can be provided, which is very important to the insulation condition assessment of cables and joints in operation.