Extended microgrids, including storage

A genuine peer-to-peer, plug-and-play subgrid

As described in a post ('Creating microgrids for connecting DG units'), microgrids can be a way to enable high penetration of Distributed Generation (DG) without the need to completely redesign the distribution grid. Microgrids can even enhance the local level of power quality thanks to DG units.

Another study by IEEE focuses on 'extended microgrids'. An extended microgrid consists of a group of radial feeders, each of which include not only loads and a generation unit, but also a storage device.

The extended microgrid is peer-to-peer; the system can continue operating with the loss of any component or generator. It is also plug-and-play; the unit can be placed at any point on the distribution grid without re-engineering.

The following load diagram shows how an extended microgrid can operate. The load has a typical 24 hour profile with peak demand at 2.5 MW. The dispatched flow from the grid is constant at 1.5 MW. The storage device will charge at night (slanted lines). During daytime, the first 2 MW is provided by the local DG unit, the remaining power required to follow the load will be supplied by the discharging storage device.