Application of Online PD Monitoring System Based on Large-scale Distributed Detection on High Voltage Cable Line

Online partial discharge (PD) monitoring system for high voltage power cable lines is different from that for other power equipment like GIS or transformer. For cable lines, the PD can be detected at cable joint and termination. Since the PD signal must decay when it propagates along the cable, distributed PD detection can increase the detection sensitivity. PD sensors and local signal processing units must be installed at each cable joint and termination, spreading over the whole cable line of several kilometers or more than ten kilometers. Therefore, all detected signals from each sensor point must be collected to the centric signal processing stage for displaying, analysis, judgment, and alarming via fiber network or wireless communication. The PD online system to operate effectively and reliability for years also required some necessary automatic-measurement functions such as auto-change of different noise filters, synchronous PRPD pattern comparison, PD identification, PD localization, and periodic system self-checking. This paper gives an example to illustrate the practical application of online PD monitoring technology for a large-scale online PD monitoring system installed on a pair of 16km-500kV XLPE cable transmission lines.