A method for determining transient errors in an unsynchronized, digital current
differential transmission line protection system includes receiving a first current
phasor measurement at a time, t, and receiving a second current phasor measurement
at time t. The second current phasor is adjusted so as to account for a determined
offset between a first sampling clock associated with the first current phasor
measurement and a second sampling clock associated with the second current phasor
measurement, thereby resulting in a rotated second current phasor measurement.
A residual transient error is then obtained from the rotated second current phasor
measurement and the first current phasor measurement.
