Network-aware Mitigation of Undetectable PMU Time Synchronization Attacks

Ezzeldin Shereen, György Dán

Abstract: Time synchronization attacks are an emerging threat to many future smart grid applications, their mitigation is thus of utmost importance. In this paper we consider the problem of mitigating attacks that are undetectable by state-of-the-art power system state estimation, in precision time protocol networks. We formulate our problem as an integer linear program and show that it is NP-hard. We then provide a polynomial time approximation algorithm through a reduction from the group Steiner tree problem. We evaluate the performance of the proposed algorithm through extensive simulations compared to a greedy heuristic. Our results show that the approximation algorithm performs within a factor 1.8 of the optimal solution for synthetic topologies, while the greedy algorithm performs even better. On IEEE benchmark power systems the approximation algorithm performs within a factor 1.1 of the optimal solution, as good as the greedy heuristic.