Detection of Irregular Sheath Current Distribution for Diagnosis of Faults in Grounding Systems of Cross-bonded Cables

Sheath currents in high voltage cable circuits have proven to be one of the most convenient indicators for assessing health. The sheath are regularly distributed with fluctuation a certain range under normal conditions, while principle distribution characteristics is still unclear when cross-bonded grounding system circuit abnormal. This paper classifies common defects into three types topologies and analyzes correspondence between conditions currents. A fault diagnosis method proposed detect irregular by quantifying difference each minor sections average loop. Sensitive analyses provided evaluate criteria, clarifying influence resistance defect. results show that can very effective ratio earth less than 7.6 short-circuit defect metallic sheath, or 1.2 ground. performance also shown efficient evaluation data collected on site.