Flexible microgrids with dynamic boundaries can further improve the resiliency and energy efficiency of microgrids with distributed energy resources (DERs). This paper focuses on optimal operation considering one of the predominant characteristics of microgrids and distribution systems – unbalanced networks and loads.

A microgrid is like a miniaturized, tightly controlled version of a power grid. Each microgrid includes generation, loads, transformers, distribution lines, protective devices, and, typically, energy storage. Several factors combine to make Puerto Rico an ideal place for solar power and microgrids. The island gets abundant sunshine and is vulnerable to destructive storms that interrupt convential electrical service.

Conventional distribution protection strategies based on overcurrent cannot reliably protect microgrids when operating in islanded mode. This article proposes specific hardware modifications to grid-forming inverters to increase their short-circuit current during electrical faults. The second innovation introduces a novel control strategy designed to preserve control stability margins.

To ensure continual power during an outage, communities and local energy planners can install microgrids, which have their own power sources and can deliver renewable energy, like solar, to strengthen community resilience. Now, there is a tool designed to connect and coordinate multiple microgrids to maintain reliable electric service, integrate more solar energy and potentially other types of renewable energy, and reduce the need for backup diesel generators, lowering costs and harmful emissions.

For the cooperative operation of networked microgrids, a distributed energy management considering network operational objectives and constraints is proposed. Considering various ownership and privacy requirements of microgrids, utility directly interfaced distributed energy resources (DERs) and demand response, a distributed optimization is proposed for obtaining optimal network operational objectives with constraints satisfied through iteratively updated price signals.

The resiliency offered by a microgrid may be lost if the microgrid is not properly protected during short-circuit faults inside its boundaries. Many studies conclude that protecting microgrids in islanded mode is very challenging due to the limited short-circuit capability of distributed energy resources (DERs). This paper demonstrates through experimental results that few modifications are required in the inverter to significantly enhance its current contribution.