Multi-microgrid Optimal Power Flow Dispatching and Collaborative Optimization Control Strategy

In allusion to the problem existing in multi-microgrid operation, a multi-microgrid power dispatching and optimization control strategy was proposed. In the proposed strategy, a multi-microgrid was divided into two parts, i.e., the microgrid control part and optimal power flow energy dispatching part. The microgrid control part included power optimization module and control module. In power optimization module a concept of dynamic active power reference value, in which the sparse communication network was cooperated with adjacent unit, was put forward, and the consistency algorithm was utilized to perform local calculation to determine equal cost incremental rate of distributed generator (abbr. DG) to obtain the reference value of dynamic active power. The active power of DG output followed the dynamic active power reference value to make the generating cost minimized, meanwhile the frequency deviation was eliminated, and therefore with such a method the additional control of frequency was not needed. Besides, the voltage controller was added in the control module and aiming at voltage inconsistency the compensation factor was added to maintain the voltage at the rated value to ensure the power quality. The optimal power flow was responsible for the power scheduling among sub-microgrids, when the capacity of sub-microgrid was insufficient the mutual aid of power among sub-microgrids could be conducted. Finally, an AC multi-microgrid model was established by MATLAB/SIMULINK, and the simulation results show that using the proposed method both economy and stability of the system were effectively improved.