Resilience Control of DC Shipboard Power Systems

Abstract

Direct current (DC) network has been recognized as a promising technique, especially for shipboard power systems (SPSs). Fast resilience control is required for an SPS to survive after faults. Towards this end, this paper proposes the indices of survivability and functionality, based on which a two-phase resilience control method is derived. The on/off status of loads are determined in the first phase to maximize survivability, while the functionality of supplying loads are maximized in the second phase. Based on a comprehensive model of a DC shipboard power systems (DC-SPS), the two-phase method renders two mixedinteger non-convex problems. To make the problems tractable, we develop second-order-cone-based convex relaxations, thus converting the problems into mixed-integer convex problems. Though this approach does not necessarily guarantee feasible, hence global, solutions to the original non-convex formulations, we provide additional mild assumptions, which ensures that the convex relaxations are exact when line constraints are not binding. In the case of inexactness, we provide a simple heuristic approach to ensure feasible solutions. Numerical tests empirically confirm the efficacy of the proposed method.

Energy Management System for Resilience-Oriented Operation of Ship Power Systems

“…The optimal variables of operation status found by optimization process are converted back to discrete variables using (23), which will be used as the load commands for the discrete loads.…”

“…Optimal power management in [22] performs load shedding and reconfiguration to minimize the impact of fault on ship power systems. A two-phase optimization problem to improve resilience was proposed in [23], in which the first phase of the optimization problem maximizes load survivability, whereas the second phase maximizes the functionality of supplying loads. A graph-theoretic method considering line capacities and load priorities was used in [24] to enhance system resilience against physical attacks on power lines.…”

“…A graph-theoretic method considering line capacities and load priorities was used in [24] to enhance system resilience against physical attacks on power lines. Although ESS are also not involved in [22][23][24], the optimization problems in these studies are still complex and challenging to solve. Thus, constraint relaxation was utilized to formulate a new low-complexity problem that ensures feasible near-optimal solutions.…”