On-Line Monitoring and Diagnosis of Typical HV Cable Sheath Faults

Abstract

The fault diagnosis system is designed and developed based on the change law of the circulating current, which realizes the online accurate identification of all types sheath faults of the high-voltage transmission cable. Firstly, through modeling and simulation, the variation characteristics of circulating current before and after the fault are obtained under the conditions of five types typical sheath defects, including poor grounding, increased single-circuit contact resistance, single-point grounding fault, interphase short circuit, and reverse connection in the cross connection grounding box. And the fault diagnosis method is concluded. Secondly, by compiling programs, designing devices, and setting fault thresholds, a fault diagnosis system for high-voltage cable sheathing is developed. Finally, the function of the device is verified by the tests on operating cables in Chengdu. The actual measurement results show that the online monitoring device can accurately capture the circulating current under fault conditions, and identify the sheath fault according to the set criteria. The defect early warning function of the device has a significant effect on improving the efficiency of sheath defect treatment and the safe operation level of the cable.