Designing Electrical Power Systems for Survivability and Quality of Service

The primary aim of the design of a shipboard electric power system has traditionally been survivability and continuity of the electrical power supply. Survivability relates to the ability of the power system, when damaged by a threat, to support the ship's ability to continue its missions. Power continuity relates to the ability of the power system to reliably provide power to ship systems under normal operations. This paper proposes new metrics for survivability and continuity of service that enable a better definition of power system requirements linked to the operational needs of the ship. For survivability, the threats for which a ship is designed are its design threats, and the required residual capability following damage from a design threat is the design threat outcome. Quality of service serves as a metric of the continuity of the electrical power supply under normal operation. Quality of service is measured in terms of a mean time between service interruption. A service interruption is defined as any interruption in the supply or deviations outside normal bounds of power quality that prevent a load from performing its assigned function.