On-Line Monitoring and Positioning of Sheath Grounding for High-Voltage Single-Core Cable Based on Pulse Difference Method

The integrity of sheath insulation of high voltage single core cable plays an important role in ensuring the design capacity, operation safety and improving the service life of the cable. The on-line monitoring and positioning of cable sheath insulation is conducive to timely detection of early cable faults, avoiding further deterioration of insulation, and ensuring the reliability of power supply system. In this paper, the existence of multi-point grounding fault is judged by detecting the circulating current of cable sheath, and the fault point is located according to pulse reflection method. In order to solve the problem of confusing fault reflection waveform caused by the reflection of cable intermediate joint, a method of cable sheath grounding fault location based on pulse difference method is proposed. The frequency varying cable model is established in ATP-EMTP, which verifies that the method can quickly and accurately measure the grounding fault distance of cable sheath.