Towards optimal PMU placement against data integrity attacks in smart grid

State estimation plays a critical role in self-detection and control of the smart grid. Data integrity attacks (also known as false data injection attacks) have shown significant potential in undermining the state estimation of power systems, and corresponding countermeasures have drawn increased scholarly interest. In this paper, we consider the existing least-effort attack model that computes the minimum number of sensors that must be compromised in order to manipulate a given number of states, and develop an effective greedy-based algorithm for optimal PMU placement to defend against data integrity attacks. We develop a greedy-based algorithm for optimal PMU placement, which can not only combat data integrity attacks, but also ensure the system observability with low overhead. The experimental data obtained based on IEEE standard systems demonstrates the effectiveness of the proposed defense scheme against data integrity attacks.