Patent ID: 8655608

Claim:
A method for detecting a fault on a conductor by a first intelligent electronic device (IED) monitoring a power system segment having a first IED and a second IED receiving a time signal from a common time reference, comprising: obtaining a first set of current measurements and associated timestamp from a clock in communication with the common time reference; the first IED receiving a second set of current measurements and associated timestamp from a clock in communication with the common time reference, from the second IED; the first IED time aligning the first set of current measurements and the second set of current measurements using the timestamps associated with the first and second sets of current measurements; calculating a first symmetrical component from the time aligned first set of current measurements; calculating a second symmetrical component from the time aligned second set of current measurements; detecting the fault on the conductor using the first and second symmetrical components; and, nullifying the fault detection by not asserting a trip signal when an error in the measurements, clock, or time alignment is detected.