Our microgrid controllers issue discusses several applications. The controllers must flexibly provide service to critical loads under a wide variety of operating conditions, including power transfers to and from the interconnecting utility and self-sufficient operation in isolated mode. Fault detection and isolation schemes must have the ability to function under a wide range of short circuit availability and power flow conditions. The state of the microgrid can be highly variable as a result of configuration changes from forced and maintenance outage conditions, different levels and rate of change of demand, and many output states of supply resources that often include photovoltaics. The physical operation of the microgrid must also respect its business model by minimizing the cost of operation.