Technical advancements in the integration of online partial discharge monitoring in distribution cable networks

Online partial discharge (PD) detection and location systems for medium-voltage (MV) cables have been developed over the past years and are currently introduced by utilities on an increasingly large scale. This paper addresses a few of the new challenges related to the integration of these systems in various cable networks. The effect of ring-main-units (RMUs) and substations on the propagation of PD signals is studied to determine feasible options for PD monitoring on two consecutive cables connected through an RMU or a substation. Different algorithms for PD pulse arrival time estimation are analyzed for robustness and PD origin location accuracy. An algorithm based on the signal energy proved to be most suitable for complex circuits where the PD shape is not only distorted by the propagation through the cable, but also by complex impedances in the RMUs along the cable under test and each cable end. Matched filters for PD detection can be improved using measured PD signals. This results in improved detection sensitivity and location accuracy.