Patent ID: 7945400

Claim:
A system for detecting a high impedance fault in a multi-grounded electrical power distribution system comprising: i) a current acquisition circuit, said current acquisition circuit generating a digital signal reflecting a current present in said multi-grounded electrical power distribution system; and ii) a processor coupled to said current acquisition circuit for executing a high-impedance fault detection algorithm and generating a high-impedance fault signal indicating the absence or presence of a high-impedance fault in said multi-grounded electrical power distribution system, wherein the processor (a) generates a detection signal from said digital signal, (b) conditions said detection signal, (c) generates a first histogram using said conditioned detection signal, (d) calculates a plurality of statistical quantities from said first histogram, (e) generates a threshold at least partially from said statistical quantities, (f) compares said conditioned detection signal to said threshold, and (g) generates said high-impedance fault signal depending on said comparison.