Formal Synthesis of Trajectories for Unmanned Aerial Vehicles to Perform Resilient Surveillance of Critical Power Transmission Lines

A smart grid is a widely distributed engineering system with overhead transmission lines. Physical damage to these power lines, from natural calamities or technical failures, will disrupt the functional integrity of the grid. To ensure the continuation of the grid's operational flow when those phenomena happen, the grid operator must immediately take steps to nullify the impacts and repair the problems, even if those occur in hardly-reachable remote areas. Emerging unmanned aerial vehicles (UAV s) show great potential to replace traditional human patrols for regularly monitoring critical situations involving the safety of the grid. The critical lines can be monitored by a fleet of UAV s, ensuring resilient surveillance. The proposed approach considers the n-1 contingency analysis to find the criticality of a transmission line. We propose a formal framework that verifies whether a given set of UAV s can perform continuous surveillance of the grid satisfying various requirements, particularly the monitoring and resiliency specifications. The verification process ultimately provides a trajectory plan for the UAV s, including the refueling schedules. The resiliency requirement of inspecting a point on a line is expressed in terms of a k - property specifying that if k UAV s fail or are compromised, there is still a UAV to collect the data on time. We evaluate the proposed framework on synthetic data based on various IEEE test bus systems.