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A Smarter Tactical Decision Aid

By LT Gregory Bredariol (USCG, MIT) LT Kevin Stevens (USCG, MIT) Joshua Nation (MIT) Andre Aboulian (MIT) Dr. Peter Lindahl (MIT) Dr. Steven Leeb (MIT)

This paper presents results from a recent installation of Nonintrusive Load Monitoring (NILM) systems aboard two operational US Coast Guard Vessels. These NILM systems analyze ship energy consumption from a single, centralized measurement point in the electric distribution system and leverage current and voltage measurements taken upstream of loads to extract operational information of individual equipment through automated signal processing and transient identification techniques. In contrast to a distributed load sensor network, the NILM allows the low-cost and robust monitoring of the shipboard electrical system and loads. The NILM systems installed feature novel noncontact current and voltage sensors, which allow easy installation on live-feeder cables with no service disruptions while keeping the installing technicians on the “safe-side” of the feeder cable insulation. Data collected by these NILMs while the ships operated at sea were used to develop new techniques and applications in energy scorekeeping, fault detection, and tactical decision-making. Specifically, this paper discusses NILM use in monitoring and analyzing loading demands of the ship’s service diesel generators, updating theoretical EPLA Load factors using the disaggregated load information, and condition-monitoring of the waste-water system via statistical analysis of associated pump operation. This later application serves as a case study showing the merits of NILM in detecting machinery faults that would otherwise go undetected and preventing complete failure of expensive and mission critical components. As a final application, NILM system data is shown to aid in tactical decision-making when the parsed data is correlated to the equipment and operational status of the vessel. Throughout the paper, representative samples of identified load power transients are presented in detail to illustrate NILM techniques and explain the merits of the NILM operation.