Distributed Transaction Optimization for Multiple Microgrids in Grid-Connected and Islanded Modes

In this paper, a distributed method is proposed based on the alternating direction multiplier method (ADMM) for energy transaction problems among multiple microgrids (MMGs) under different operating modes. Firstly, a comprehensive transaction framework of microgrid (MG) is formulated that minimizes the operation cost while satisfying various operation constraints in Grid-Connected and Islanded modes. Then, in order to alleviate the communication burdens, the transaction optimization problems are decomposed into regional subproblems, and the global optimal solutions can be obtained by solving the subproblems of each region iteratively. The privacy of individual microgrids (MGs) can be protect well due to the proposed method only need the local computation with neighbor-wise energy exchanging, which conforms to the operating philosophy of multilateral transaction power markets. Finally, simulations of MGs in different operating modes are conducted to demonstrate the underlying benefits of energy transactions for MGs in grid-connected mode.