Distributed Frequency Control of Heterogeneous Resources-Powered Islanded Microgrid with Enhanced Economic Operation

The dynamic frequency control processes and economic operations of the large-scale power grids are separately applied. However, for the small inertia microgrids (MGs), the operating conditions tend to be more volatile due to relatively more uncontrollable entities being integrated. Hence, the frequency control solution of MGs should take the economic operation of MGs at a time-scale that is much shorter than the traditional economic dispatch of the large power grids. To this end, this paper proposes a two-layer coordinated frequency control strategy for MGs with enhanced economic operation consideration. For the upper optimal power-sharing layer, the distributed bisection algorithm is applied to obtain the optimal power sharing among heterogeneous resources. For the lower control layer, an autonomous control strategy that integrates both primary control and secondary control reference is applied by adopting the event-trigger mechanism. The proposed control approach can realize integrated active power control of MGs by simultaneously taking primary control, secondary control, and economic operation into consideration. Simulation studies with a heterogeneous resources-powered MG demonstrate its effectiveness.