Fault locating in ungrounded and compensated systems

This paper presents new approaches to locating ground faults for ungrounded and Peterson coil grounded systems. The system approach couples information from a relay located at a substation and remote ground-fault detectors to indicate the fault phase, the supply feeder to the fault, an estimate of the fault distance, and the branch circuit with the fault. A diagnostic signal generator that operates at a distinct frequency other than the power-line frequency provides a circuit path and signal to help to locate the ground fault. The remote ground-fault indicator or hand-held detector is a robust device that gives indication of a ground fault on a particular circuit. It is sensitive in detecting small diagnostic currents. The DCHV breaks down the fault point again before injecting the diagnosis signal current into the de-energized system.