Detection of time spoofing attacks on GPS synchronized phasor measurement units

This paper builds a foundation for detecting spoofed GPS signals through multiple PMU comparison. Frequency measurements from PMUs in ERCOT and the Eastern Grid are used as the basis for calculations and simulated GPS signal time shifts. When PMUs in a single control area are compared, the difference between the individual PMU's frequency-based integrated time error and the average time error between PMUs is small, but when forced by a spoofed time-shifting signal, this difference becomes significant and detectable. Positive and negative phase angle shifts are considered, and an example of calculations during a significant power system transient is shown. The detection of fast or slow time-shifting events is possible by using a sliding averaging window with the frequency measurements.