ALGORITHMS FOR THE DETECTION OF NOISE FREQUENCIES GENERATED BY HIGH IMPEDANCE FAULTS.

Digital computation techniques are being used increasingly in power distribution systems for purposes of control and protection. One application of these technics involves the detection of high impedance faults. it is believed such faults produce certain characteristic noise frequencies, and that detection of such frequencies may provide a reliable and economic indicator of a faulted line. This paper describes two algorithms which are used in this fault detection: event detection, and the detection of the characteristic noise frequencies. The event detection routine is accomplished by a present-cycle to past-cycle current-comparison technique. When an event is indicated, the characteristic frequency detection routine is initiated. This routine compares the energy in high frequency current noise against the energy contained in the 60 Hz fundamental current and its low order harmonics. This comparison, averaged over a given period of time, provides a basis for the identification of a high impedance fault. This paper also gives background of the nature of high impedance faults as well as describing the microprocessor system which will be used to implement algorithms.

ALGORITHMS FOR THE DETECTION OF NOISE FREQUENCIES GENERATED BY HIGH IMPEDANCE FAULTS. Academic Article