Diagnosis and Location of High-voltage Cable Fault Based on Sheath Current

Using conventional methods, such as bridge method, traveling wave method, etc., it is unlikely to detect the fault location in a short time. A new monitoring and diagnosis method for high-voltage cables based on sheath current is proposed. The sheath current is measured to locate the cross-connected segment of the fault, leading to reduce the maintenance time. Considering the operation mode, cable parameters and line length, the sheath current equivalent circuit model of the cross-connected cable system was established according to the one-line laying type. Then a single-phase short-circuit fault in a cross-connected cable system was simulated. The results show that when the cable fault occurs, the difference of the sheath currents detected in the cross-connected sections are obvious. The grounding resistance, laying distance and cable length have less influence on the fault location. Therefore, based on the comparison among the sheath currents measured at the different minimum cross-section, the single-phase short-circuit fault can be accurately located.