A Novel Diagnosis and Location Method of Short-Circuit Grounding High-Impedance Fault for a Mesh Topology Constant Current Remote Power Supply System in Cabled Underwater Information Networks

Cabled underwater information networks (CUINs) have evolved over the last decade to provide abundant power and broad bandwidth communication to enable marine science. To ensure reliable operation of CUINs, it is essential to have the technology for high-impedance fault diagnosis and isolation with high reliability and accuracy. The short-circuit grounding high-impedance fault status of mesh topology constant current remote supply system was diagnosed by analyzing the variation difference of equivalent current in the Laplace transform domain. Shore power feeding equipment (SPFE) supplied the power for underwater system individually from both terminals, and the fault location was located by calculating the shunt loss of the current in the trunk before and after the fault. Thus, the fault was isolated to maintain normal operation of the rest of the system and improve the reliability of CUINs. According to the established typical mesh topology constant current remote supply system circuit model, the fault location scheme was designed to simulate the faults of the cable sections in the different links in the constant current remote supply system, and the changes of current located at the primary nodes (PNs) in the Laplace transform domain before and after the fault were analyzed. The results show that the equivalent current of each PN changes when a fault occurs in the system, and the location of the fault point can be analyzed by comparing the shunt loss of the current in the trunk before and after the fault. The designed method of short-circuit grounding high-impedance fault diagnosis and location for a constant current remote supply system is suitable for the fault monitoring and judgment of CUINs with high feasibility and practicality. Furthermore, it provides technical support for the resulting effective determination of faults, isolation of faults, protection of equipment, and improvement of the system reliability.