High-impedance fault detection and isolation system

摘要

A high-impedance system that utilizes asynchronous, line-mounted single-phase current and voltage sensors with rolling data logs and a common clock or other event trigger to synchronize the signals to a common time scale whenever a fault event is detected. The use of asynchronous, single-phase current and voltage angle sensors with rolling data logs, along with a common clock to synchronize the signals to common time scale whenever a fault event is detected, avoids the need for simultaneous three-phase current measurement. Integration of information, triggered by the detection of a loss or sufficient change of current on three or four (with a neutral current) devices, is used to determine the presence and direction of high-impedance faults and then report it, typically to a central control center via SCADA or another communication system, which implements fault isolation.

主权项

1. A high-impedance fault detection and response system for a three phase electric power line having three phase conductors, comprising:
a set of three current phase sensors, each electrically coupled to and asynchronously monitoring phase current flowing in an associated phase conductor; each current phase sensor having a data buffer for storing a recent history phase current waveform data file for its associated phase current; an event detector operative for event detection of a potential high-impedance fault on the electric power line; each current phase sensor operative for uploading its recent history phase current waveform data file in response to the event detection; a controller operative for receiving the recent history phase current waveform data files, computationally sequencing the phase current waveforms, and analyzing the sequence currents to verify that a high-impedance fault has occurred and identify a faulted phase involved in the high-impedance fault.