Biblio

This paper introduces combined data integrity and availability attacks to expand the attack scenarios against power system state estimation. The goal of the adversary, who uses the combined attack, is to perturb the state estimates while remaining hidden from the observer. We propose security metrics that quantify vulnerability of power grids to combined data attacks under single and multi-path routing communication models. In order to evaluate the proposed security metrics, we formulate them as mixed integer linear programming (MILP) problems. The relation between the security metrics of combined data attacks and pure data integrity attacks is analyzed, based on which we show that, when data availability and data integrity attacks have the same cost, the two metrics coincide. When data availability attacks have a lower cost than data integrity attacks, we show that a combined data attack could be executed with less attack resources compared to pure data integrity attacks. Furthermore, it is shown that combined data attacks would bypass integrity-focused mitigation schemes. These conclusions are supported by the results obtained on a power system model with and without a communication model with single or multi-path routing.

Modern power systems heavily rely on the associated cyber network, and cyber attacks against the control network may cause undesired consequences such as load shedding, equipment damage, and so forth. The behaviors of the attackers can be random, thus it is crucial to develop novel methods to evaluate the adequacy of the power system under probabilistic cyber attacks. In this study, the external and internal cyber structures of the substation are introduced, and possible attack paths against the breakers are analyzed. The attack resources and vulnerability factors of the cyber network are discussed considering their impacts on the success probability of a cyber attack. A procedure integrating the reliability of physical components and the impact of cyber attacks against breakers are proposed considering the behaviors of the physical devices and attackers. Simulations are conducted based on the IEEE RTS79 system. The impact of the attack resources and attack attempt numbers are analyzed for attackers from different threats groups. It is concluded that implementing effective cyber security measures is crucial to the cyber-physical power grids.