Distributed Estimation of Power System Oscillation Modes under Attacks on GPS Clocks

Phasor Measurement Units (PMU) are playing an increasingly important role in wide-area monitoring and control of power systems. PMUs allow synchronous real-time measurements of voltage, phase angle and frequency from multiple remote locations in the grid, enabled by their ability to align to Global Position System (GPS) clocks. Given that this ability is vulnerable to GPS spoofing attacks, which have been confirmed easy to launch, in this paper we propose a distributed real-time wide-area oscillation estimation approach that is robust to GPS spoofing on PMUs and their associated Phasor Data Concentrators (PDCs). The approach employs the idea of checking update consistency with histories and across distributed nodes and can tolerate up to one third of compromised nodes. It can be implemented in a completely decentralized architecture and in a completely asynchronous way. The effectiveness of the approach is confirmed by numerical simulations of the IEEE 68-bus power system models.