Detection and Localization of Defects in Cable Sheath of Cross-Bonding Configuration by Sheath Currents

Nowadays, many researchers are focusing on on-line condition monitoring of high-voltage insulated cable systems to prevent failures. With the aim of reducing the voltage induced in the cable sheaths, cross-bonding (CB) grounding cable systems are used in long distance power transmission land lines. This paper proposes a new criterion for the detection and localization of defects that might occur in the cable sheath when a CB configuration is adopted. The proposed criterion can be applied at different levels of load current. For the application of the criterion, the cable system under evaluation is modeled using the alternative transient program (ATP) software. Various practical cases were studied, showing the effectiveness of the criterion for the detection and localization of different types of defects in simulated cable systems. Furthermore, in order to validate the criteria adopted for the defect detection, based on the ATP model, a real defected case was evaluated. The results obtained proved that this criterion is suitable for the detection and localization of defects in the cable sheaths, when on-line measurements are performed in monitoring applications.