Impact of GPS signal quality on the performance of phasor measurements

Wide area measurements are becoming the basis of power system monitoring, protection and control. The frequency disturbance recorder (FDR) is actually a single-phase phasor measurement unit (PMU). It measures the voltage amplitude, angle and frequency from a single-phase 120-V wall outlet. Currently, the accuracy of synchrophasor measurements depends heavily on the precise time signal provided by global position system (GPS). This paper explores the impact of GPS signal loss on the measurement accuracy through a series of tests on FDR units including both regular and high sensitivity GPS receivers. It was shown the phase angle is more sensitive to GPS signal loss than frequency measurements.