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 (HV) 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 cables sheath when a CB configuration is adopted. The criterion proposed can be applied at different levels of load current. For the application of the criterion, the cable system under evaluation is modeled using the 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 cables sheath, when on-line measurements are performed in monitoring applications