Preventing Line Faults with Continuous Monitoring Based on Current Traveling Waves

This paper presents a novel method to continuously monitor a power line for fault precursors. Based on a double-ended travelingwave fault-locating method to locate disturbances, the monitoring logic triggers on current traveling waves as small as a few tens of primary amperes. The logic tabulates locations of the detected internal events and alarms if the event count exceeds a userdefined threshold for any location along the line. We expect the line-monitoring logic to detect organic and chemical contamination of insulators, cracked insulators, encroaching vegetation, and other events with accuracy of about 300 m. This paper describes the logic, shares key implementation details, and reports on selected field events captured from the prototype version of a line protective relay with an embedded line-monitoring logic.