This paper presents a load switching group based energy management system
(LSG-EMS) for operating microgrids on a distribution feeder powered by one or
multiple grid-forming distributed energy resources. Loads on a distribution
feeder are divided into load switching groups that can be remotely switched on
and off. The LSG-EMS algorithm, formulated as a mixed-integer linear
programming (MILP) problem, has an objective function of maximizing the served
loads while minimizing the total number of switching actions. A new set of
topology constraints are developed for allowing multiple microgrids to be
formed on the feeder and selecting the optimal supply path. Customer comfort is
accounted for by maximizing the supply duration in the customer preferred
service period and enforcing a minimum service duration. The proposed method is
demonstrated on a modified IEEE 33-bus system using actual customer data.
Simulation results show that the LSG-EMS successfully coordinates multiple
grid-forming sources by selecting an optimal supply topology that maximizes the
supply period of both the critical and noncritical loads while minimizing
customer service interruptions in the service restoration process.Comment: 5 pages, 7 figures, submitted to 2021 IEEE PES General Meetin