Trajectory Synthesis for a UAV Swarm to Perform Resilient Requirement-Aware Surveillance: A Smart Grid-based Study

Abstract

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 (UAVs) 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 UAVs to ensure a resilient surveillance system. 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 UAVs (i.e., a UAV swarm) 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 UAVs, 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 UAVs fail or compromised still there is a UAV to collect the data at the point within on time. We evaluate the proposed framework on synthetic data based on various IEEE test bus systems.