A GPS Spoofing Resilient WAMS for Smart Grid

Smart grids provide efficiency in energy distribution, easy identification of disturbance sources, and fault prediction. To achieve these benefits a continuous monitoring of voltage and current phasors must be performed. Phasor Measurement Units (PMUs) allow measurements of the phasors. A Wide Area Measurement System uses PMUs placed in different locations to assess the status of the power grid. To correctly analyze the phasors provided by PMUs, phasors must refer to the same time. For this reason each PMU uses the clock provided by a GPS receiver. GPS receiver is vulnerable to spoofing attack and it is a single point of failure. In this context we examined Network Time Protocol (NTP) as an alternative time source when the GPS receiver is compromised. In this paper a resilient architecture is proposed that is able to detect and react to the GPS spoofing attack. Experimental tests have shown the effectiveness of our solution