Patent ID: 8355882

Claim:
A method for detecting high impedance faults, comprising: receiving, using a device, an input waveform from a circuit, wherein the circuit is a power distribution network; computing, using the device, a root mean square of the input waveform for each of a plurality of consecutive first time periods; fitting, using the device, a regression line to the root mean squares; computing, using the device, a deviation between the regression line and the root mean squares for each of a plurality of consecutive second time periods; determining, using the device, whether the deviations are above a threshold, wherein determining whether the deviations are above the threshold comprises selecting a continuous number of the second time periods for analysis, computing a mean of the deviations within the selected time period and computing a maximum of the deviations within the selected time period minus the mean, wherein the deviations are above the threshold when the mean exceeds a predetermined percentage of the maximum; and outputting, using the device, a first value indicating that a high impedance fault has occurred in the circuit when the deviation is above the threshold and a second value indicating that a high impedance fault did not occur in the circuit when the deviation is below the threshold, wherein the input waveform is generated without being triggered by the device, and wherein machine code is executed by a processor of the device to compute the deviation between the regression line and the root mean squares for each of the plurality of consecutive second time periods.