ADMM-based optimum power flow in nested microgrids

Nested microgrids is an emerging configuration of microgrids where one microgrid can operate as part of a bigger microgrid to ensure supply and increase reliability. Each microgrid contains dispatchable and non-dispatchable distributed generators (DGs) from renewable energy sources (RES), and loads so it can be optimized to be self-sufficient. Yet, it is given the option to buy power from the upper level to meet its deficit or sell its surplus of power to the lower level. This paper proposed a method to optimize DGs output power and the power trading between upper and lower microgrids with the distributed optimization technique. Using the alternating direction method of multipliers (ADMM) algorithm, each level is optimized in parallel for a day-ahead energy management system (EMS). Then the boundary variables are checked until convergence criteria are met. A case study was executed on IEEE 33-bus system to evaluate the performance of the proposed technique.