Power Monitoring Beyond Radial Distribution Networks

Typical “last quarter mile” power distribution employs a radial network of electrical panels, feeders, and subpanels. Monitoring and fault localization on radial grids are relatively straightforward, as feeder connections to a panel provide a convenient single-access point for measuring current, voltage, and aggregate power. When multiple generating sources feed a local grid to provide redundancy or flexibility in the integration of diverse sources, a ring bus may be employed to power a mix of radial subnetworks. Monitoring individual loads from measurements made on a ring bus requires the combination of multiple measurements. These measurements must be precisely synchronized. In many cases, wireless time synchronization may be difficult to transmit, and wired time synchronization may be impractical to retrofit. In these scenarios, the power system itself can be used to align the data. This article introduces practical techniques to time-align measurements collected on a ring bus in order to monitor individual load power consumption. Marine microgrids are used to illustrate the presented time-alignment algorithms, and the results are demonstrated on ring-bus microgrid hardware.