Delcourt, MargueriteShereen, EzzeldinDan, GyorgyLe Boudec, Jean-YvesPaolone, Mario2021-08-092021-08-092021-08-092021-05-0610.1109/TSG.2021.3078104https://infoscience.epfl.ch/handle/20.500.14299/180489Phasor measurement units (PMU) rely on an accurate time-synchronization to phase-align the phasors and timestamp the voltage and current phasor measurements. Among the symmetrical components computed from the phasors in three-phase systems, the standard practice only uses the direct-sequence component for state estimation and bad data detection (BDD). Time-synchronization attacks (TSAs) can compromise the measured phasors and can, thus, significantly alter the state estimate in a manner that is undetectable by widely used power-system BDD algorithms. In this paper we investigate the potential of utilizing the three-phase model instead of the direct-sequence model for mitigating the vulnerability of state estimation to undetectable TSAs. We show analytically that if the power system is unbalanced then the use of the three-phase model as input to BDD algorithms enables to detect attacks that would be undetectable if only the direct-sequence model was used. Simulations performed on the IEEE 39-bus benchmark using real load profiles recorded on the grid of the city of Lausanne confirm our analytical results. Our results provide a new argument for the adoption of three-phase models for BDD, as their use is a simple, yet effective measure for reducing the vulnerability of PMU measurements to TSAs.Phasor measurement unitsTransmission line measurementsState estimationSynchronizationPower systemsPhase measurementMeasurement uncertaintytext::journal::journal article::research article