DETECTION OF ARCING FAULTS ON DISTRIBUTION FEEDERS.
Academic Article
Overview
Overview
abstract
Some distribution primary faults draw little fault current and are therefore difficult to detect with existing overcurrent protection systems. The problem of detecting high impedance faults is examined from the perspective of current utility protection practices and it is shown why conventional overcurrent protection systems may not detect such faults. Research resulted in the design and testing of a microcomputer-based prototype of an arcing, high impedance fault detector. The detection technique is based on an increase in the high frequency (2-10 kHz) component of distribution feeder current caused by the arcing associated with many high impedance faults. The proposed detection system is explained. The theory is supported by field data measurements and analysis of staged distribution primary faults and normal system conditions. The design and demonstration of the prototype is explained. The device successfully detected many faults of greater than 5-10 A on a typical distribution feeder without false trips. General application of this fault detection technique is considered, particularly with regard to its strengths and limitations.
