Patent ID: 11933834
Assignee: 3M INNOVATIVE PROPERTIES COMPANY
Field: Measurement (Instruments)
Classification: CPC G  H  Y | IPC G  H

Claim 0:
1. A method of detecting self-clearing, sub-cycle faults, comprising:
sensing a current condition and a voltage condition at a location along a power cable;
relaying sensed conditions to an analyzing device, the analyzing device including at least one of a current peak detector, a fast fault detector and high speed sampling;
determining the presence of a measured current value;
if the measured current value is greater than a current threshold value, performing a faulted circuit indicator (FCI) analysis to determine the presence or absence of an FCI fault;
if an FCI fault is absent, performing an incipient fault analysis, wherein the root-mean-square (RMS) current values before and after a threshold event are compared and the voltage total harmonic distortion (THD) before and after the event are compared; and
wherein if the two current values are within a first predetermined percentage and the THD values differ by a second predetermined percentage, then an incipient fault is reported.